OFFICE ACTION
This application has been assigned or remains assigned to Technology Center 1700, Art Unit 1774 and the following will apply for this application:
Please direct all written correspondence with the correct application serial number for this application to Art Unit 1774.
Telephone inquiries regarding this application should be directed to the Electronic Business Center (EBC) at http://www.uspto.gov/ebc/index.html or 1-866-217-9197 or to the Examiner at (571) 272-1139. All official facsimiles should be transmitted to the centralized fax receiving number (571)-273-8300.
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Priority
Acknowledgment is made of a claim for foreign priority under 35 U.S.C. § 119(a)-(d). All of the CERTIFIED copies of the priority documents have been received in this national stage application from the International Bureau (PCT Rule 17.2(a)).
Information Disclosure Statement
Note the attached PTO-1449 forms submitted with the Information Disclosure Statements.
Drawings
The drawings filed 5 DEC 2022 are objected to under 37 CFR § 1.84 in view of the following deficiencies that require correction:
The apparently handwritten reference characters forming the Figures are of inadequate clarity (not uniformly thick and well-defined - 37 CFR 1.84(l)) and too small as noted below: All drawings must be made by a process which will give them satisfactory reproduction characteristics. Every line, number, and letter must be durable, clean, black (except for color drawings), sufficiently dense and dark, and uniformly thick and well-defined. The weight of all lines and letters must be heavy enough to permit adequate reproduction. This requirement applies to all lines however fine, to shading, and to lines representing cut surfaces in sectional views. For example, reference character “29” in certain Figures appears to be the letter "g” - thus at least this reference character is not well-defined and contributes to confusion and/or contradiction with the written specification.
The drawings contain improper sectional views. The plane upon which a sectional view is taken should be indicated on the view from which the section is cut by a broken line. The ends of the broken line should be designated by Arabic or Roman numerals corresponding to the view number of the sectional view, and should have arrows to indicate the direction of sight (37 CFR 1.84(h)(3)). For example, Figure 5 should be a sectional view taken along line 5-5 in Figure 4 (not sectional line A-A). All sectional views should be corrected in accordance with 37 CFR 1.84(h)(3).
The reference characters are also too small. Numbers, letters, and reference characters must measure at least (1/8 inch) in height - 37 CFR 1.84(p).
Applicant should review the specification and drawing Figures to ensure a proper one-to-one correspondence between the specification and drawings in accordance with MPEP 608.01(g) and 37 CFR 1.84(f). The brief description of the drawings and the descriptive portion of the specification will require revision in accordance with any drawing objections listed herein or those noticed by Applicant during said review.
From MPEP 608.01(g): The reference characters must be properly applied, no single reference character being used for two different parts or for a given part and a modification of such part. See 37 CFR 1.84(p). Every feature specified in the claims must be illustrated, but there should be no superfluous illustrations.
INFORMATION ON HOW TO EFFECT DRAWING CHANGES
Replacement Drawing Sheets
Drawing changes must be made by presenting replacement figures which incorporate the desired changes and which comply with 37 CFR 1.84. An explanation of the changes made must be presented either in the drawing amendments, or remarks, section of the amendment. Any replacement drawing sheet must be identified in the top margin as “Replacement Sheet” (37 CFR 1.121(d)) and include all of the figures appearing on the immediate prior version of the sheet, even though only one figure may be amended. The figure or figure number of the amended drawing(s) must not be labeled as “amended.” If the changes to the drawing figure(s) are not accepted by the examiner, applicant will be notified of any required corrective action in the next Office action. No further drawing submission will be required, unless applicant is notified.
Identifying indicia, if provided, should include the title of the invention, inventor’s name, and application number, or docket number (if any) if an application number has not been assigned to the application. If this information is provided, it must be placed on the front of each sheet and centered within the top margin.
Annotated Drawing Sheets
A marked-up copy of any amended drawing figure, including annotations indicating the changes made, may be submitted or required by the examiner. The annotated drawing sheets must be clearly labeled as “Annotated Marked-up Drawings” and accompany the replacement sheets.
Timing of Corrections
Applicant is required to submit acceptable corrected drawings within the time period set in the Office action. See 37 CFR 1.85(a). Failure to take corrective action within the set period will result in ABANDONMENT of the application.
If corrected drawings are required in a Notice of Allowability (PTOL-37), the new drawings MUST be filed within the THREE MONTH shortened statutory period set for reply in the “Notice of Allowability.” Extensions of time may NOT be obtained under the provisions of 37 CFR 1.136 for filing the corrected drawings after the mailing of a Notice of Allowability.
Specification
The specification has not been checked to the extent necessary to determine the presence of all possible minor errors. Applicant's cooperation is requested in correcting any errors of which applicant may become aware in the specification.
The substitute abstract is acceptable.
The title of the invention is not descriptive. A new title is required that is clearly indicative of the invention to which the claims are directed (MPEP 606.01) by mentioning the seal with a throttle gap.
Claim Rejections - 35 U.S.C. § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
The inquiry during examination is patentability of the invention as the inventor or a joint inventor regards such invention. If the claims do not particularly point out and distinctly claim that which the inventor or a joint inventor regards as his or her invention, the appropriate action by the examiner is to reject the claims under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph. In re Zletz, 893 F.2d 319, 13 USPQ2d 1320 (Fed. Cir. 1989).
Claims 1-17 are rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or joint inventor regards as the invention.
One of the purposes of 35 U.S.C. § 112(b) “is to provide those who would endeavor, in future enterprise, to approach the area circumscribed by the claims of a patent, with adequate notice demanded by due process of law, so that they may more readily and accurately determine the boundaries of protection involved and evaluate the possibility of infringement and dominance.” In re Hammack, supra. As set forth in Amgen Inc. v. Chugai Pharmaceutical Co., Ltd., 927 F.2d 1200, 1217, 18 USPQ2d 1016, 1030 (Fed. Cir. 1991).
The statute requires that “[t]he specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.” A decision as to whether a claim is invalid under this provision requires a determination whether those skilled in the art would understand what is claimed. See Shatterproof Glass Corp. v. Libbey-Owens Ford Co., 758 F.2d 613, 624, 225 USPQ 634, 641 (Fed. Cir. 1985) (claims must “reasonably apprise those skilled in the art” as to their scope and be “as precise as the subject matter permits.”).
Moreover, 35 U.S.C. § 112(b) requires a claim to particularly point out and distinctly claim the subject matter which applicant regards as the invention. Under In re Hammack, 427 F.2d 1378, 166 USPQ 204 (CCPA 1970) and In re Moore, 169 USPQ 236 (CCPA 1971), claims must be analyzed to determine their metes and bounds so that it is clear from the claim language what subject matter the claims encompass. This analysis must be performed in light of the applicable prior art and the disclosure. The definiteness of the claims is important to allow others who wish to enter the market place to ascertain the boundaries of protection that are provided by the claims. Ex parte Kristensen, 10 USPQ 2d 1701, 1703 (BPAI 1989).
NOTE: Per 37 CFR 1.75(c), dependent claims shall be construed to include all the limitations of the claim incorporated by reference into the dependent claim. Accordingly, by definition, any claims that depend from a claim that is deemed indefinite under 35 USC 112(b) will also be considered indefinite and identified in the list of rejected claims above, even if such claims are themselves free of indefiniteness under § 112(b).
The pending claims fail to particularly point out and distinctly claim the subject matter which applicant regards as the invention and are therefore of indeterminate scope for the following reasons:
A broad range or limitation together with a narrow range or limitation that falls within the broad range or limitation (in the same claim) is considered indefinite, since the resulting claim does not clearly set forth the metes and bounds of the patent protection desired. See MPEP § 2173.05(c). Note the explanation given by the Board of Patent Appeals and Interferences in Ex parte Wu, 10 USPQ2d 2031, 2033 (Bd. Pat. App. & Inter. 1989), as to where broad language is followed by "such as" and then narrow language. The Board stated that this can render a claim indefinite by raising a question or doubt as to whether the feature introduced by such language is (a) merely exemplary of the remainder of the claim, and therefore not required, or (b) a required feature of the claims. Note also, for example, the decisions of Ex parte Steigewald, 131 USPQ 74 (Bd. App. 1961); Ex parte Hall, 83 USPQ 38 (Bd. App. 1948); and Ex parte Hasche, 86 USPQ 481 (Bd. App. 1949). In the present instance, claim 2 recites the broad recitation “wherein the cylindrical length (L) of the throttle gap is equal to at least 2/3 of the diameter of the plunger” and the claim also recites “and ideally corresponds at least to the entire diameter of the plunger” which is the narrower statement of the range/limitation.
Claims 1-17: all occurrences of “the plunger shaft”, “the housing”, and “the housing portion” in these claims lack antecedent basis.
Claim 4, line 3: “the inner enclosing surface of the bushing” lacks antecedent basis.
Claim 4: the phrase "preferably as a flat bevel with a bevel angle of 30 degrees or less” in line 4 renders the claim indefinite because it is unclear whether the limitations following the word “preferably” are part of the claimed invention. See MPEP § 2173.05(d).
Claim 5, line 6: : the phrase "which preferably forms approximately a bevel angle of 45 degrees to the longitudinal axis of the bushing” in line 6 renders the claim indefinite because it is unclear whether the limitations following the word “preferably” are part of the claimed invention. See MPEP § 2173.05(d). Moreover, the claim terms “steeper” and “flatter” are potentially indefinite relative terms which require references to the angles “45 degrees” and “30 degrees or less” in the claim for proper context and definiteness. Thus, any revised version of claim 5 must include these angles in conjunction with the “steeper” and “flatter” terms when addressing the “preferably” issue.
Claim 9: “the drive piston” lacks antecedent basis.
Claim 10: all occurrences of “the drive piston” lack antecedent basis. This claim is worded in an awkward, fragmented, and confusing manner - the hyphens should be removed to improve clarity.
Claim 11: “the drive piston” lacks antecedent basis. The language “wherein the bushing is held in the radial direction more than to an insignificant extent in the housing portion surrounding it” is of indeterminate scope - the metes and bounds of “an insignificant extent” is unknown.
Claim 12: “the drive side” lacks antecedent basis. It is unclear what elements the vague term “them” is referencing.
Claim 13: The language “numerous parts“” is of indeterminate scope - the metes and bounds of “numerous” is unknown.
Claim 13: the phrase "ideally of three” in line 3 renders the claim indefinite because it is unclear whether the limitations following the word “ideally” are part of the claimed invention. See MPEP § 2173.05(d).
Claim 14 is grossly indefinite since “preferably by being equipped on its outer enclosure - at least in part, better completely - with a bearing sleeve (42) made of more than only insignificantly compressible material, ideally of a soft elastomer or rubber” and “preferably having a bearing sleeve (42) made of more than insignificantly compressible material on its outer periphery - at least partly, better completely” renders the claim indefinite because it is unclear whether the limitations following the words “preferably”, “ideally” and “at least in part, better completely” are part of the claimed invention. See MPEP § 2173.05(d). Moreover, “at least in part, better completely” and “at least in partly, better completely” are considered gibberish lacking any fragment of clarity.
Claim 14: The occurrences of ”more than only insignificantly compressible material” is of indeterminate scope - the metes and bounds of such material is unknown. The recitation of “the rings” lacks antecedent basis. This claim is worded in an awkward, fragmented, and confusing manner - the hyphens should be removed to improve clarity.
Claim 15: “the outer enclosing surface” lacks antecedent basis.
Claim 16: the phrase "which preferably forms approximately a bevel angle of 45 degrees to the longitudinal axis of the bushing” renders the claim indefinite because it is unclear whether the limitations following the word “preferably” are part of the claimed invention. See MPEP § 2173.05(d).
Claim 16: the phrase “in particular to its temperature-dependent viscosity and/or to the particles carried by the fluid” renders the claim indefinite because it is unclear whether the limitations following the word “preferably” are part of the claimed invention. See MPEP § 2173.05(d).
Claim 16, last line” “the same identifying name” lacks antecedent basis and is of indeterminate scope.
Claim 17, line 3: do the “bushings” have any relationship to the bushing recited in claim 1? The recitations of “the framework”, “the prescribed operation”, “the thermal conduct modifications”, and “the current assignment or process” all lack antecedent basis.
Claim Rejections - 35 USC § 103
The terms used in this respect are given their broadest reasonable interpretation in their ordinary usage in context as they would be understood by one of ordinary skill in the art, in light of the written description in the specification, including the drawings, without reading into the claim any disclosed limitation or particular embodiment. See, e.g., In re Am. Acad. of Sci. Tech. Ctr., 367 F.3d 1359, 1364 (Fed. Cir. 2004); In re Hyatt, 211 F.3d 1367, 1372 (Fed. Cir. 2000); In re Morris, 127 F.3d 1048, 1054-55 (Fed. Cir. 1997); In re Zletz, 893 F.2d 319, 321-22 (Fed. Cir. 1989). The Examiner interprets claims as broadly as reasonable in view of the specification, but does not read limitations from the specification into a claim. Elekta Instr. S.A.v.O.U.R. Sci. Int'l, Inc., 214 F.3d 1302, 1307 (Fed. Cir. 2000).
To determine whether subject matter would have been obvious, "the scope and content of the prior art are to be determined; differences between the prior art and the claims at issue are to be ascertained; and the level of ordinary skill in the pertinent art resolved .... Such secondary considerations as commercial success, long felt but unsolved needs, failure of others, etc., might be utilized to give light to the circumstances surrounding the origin of the subject matter sought to be patented." Graham v. John Deere Co. of Kansas City, 383 U.S. 1, 17-18 (1966).
The Supreme Court has noted:
Often, it will be necessary for a court to look to interrelated teachings of multiple patents; the effects of demands known to the design community or present in the marketplace; and the background knowledge possessed by a person having ordinary skill in the art, all in order to determine whether there was an apparent reason to combine the known elements in the fashion claimed by the patent at issue.
KSR Int'l Co. v. Teleflex Inc., 127 S.Ct. 1727, 1740-41 (2007). "Under the correct analysis, any need or problem known in the field of endeavor at the time of invention and addressed by the patent can provide a reason for combining the elements in the manner claimed." (Id. at 1742).
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
The instant office action conforms to the policies articulated in the Federal Register notice titled “Updated Guidance for Making a Proper Determination of Obviousness” at 89 Fed. Reg. 14449, February 27, 2024, wherein the Supreme Court’s directive to employ a flexible approach to understanding the scope of prior art is reflected in the frequently quoted sentence, ‘‘A person of ordinary skill is also a person of ordinary creativity, not an automaton.’’ Id. at 421, 127 S. Ct. at 1742. In this section of the KSR decision, the Supreme Court instructed the Federal Circuit that persons having ordinary skill in the art (PHOSITAs) also have common sense, which may be used to glean suggestions from the prior art that go beyond the primary purpose for which that prior art was produced. Id. at 421–22, 127 S. Ct. at 1742. Thus, the Supreme Court taught that a proper understanding of the prior art extends to all that the art reasonably suggests, and is not limited to its articulated teachings regarding how to solve the particular technological problem with which the art was primarily concerned. Id. at 418, 127 S. Ct. at 1741 (‘‘As our precedents make clear, however, the analysis need not seek out precise teachings directed to the specific subject matter of the challenged claim, for a court can take account of the inferences and creative steps that a person of ordinary skill in the art would employ.’’). ‘‘The obviousness analysis cannot be confined . . . by overemphasis on the importance of published articles and the explicit content of issued patents.’’ Id. at 419, 127 S. Ct. at 1741. Federal Circuit case law since KSR follows the mandate of the Supreme Court to understand the prior art— including combinations of the prior art—in a flexible manner that credits the common sense and common knowledge of a PHOSITA. The Federal Circuit has made it clear that a narrow or rigid reading of prior art that does not recognize reasonable inferences that a PHOSITA would have drawn is inappropriate. An argument that the prior art lacks a specific teaching will not be sufficient to overcome an obviousness rejection when the allegedly missing teaching would have been understood by a PHOSITA—by way of common sense, common knowledge generally, or common knowledge in the relevant art. For example, in Randall Mfg. v. Rea, 733 F.3d 1355 (Fed. Cir. 2013), the Federal Circuit vacated a determination of nonobviousness by the Patent Trial and Appeal Board (PTAB or Board) because it had not properly considered a PHOSITA’s perspective on the prior art. Id. at 1364. The Randall court recalled KSR’s criticism of an overly rigid approach to obviousness that has ‘‘little recourse to the knowledge, creativity, and common sense that an ordinarily skilled artisan would have brought to bear when considering combinations or modifications.’’ Id. at 1362, citing KSR, 550 U.S. at 415–22, 127 S. Ct. at 1727. In reaching its decision to vacate, the Federal Circuit stated that by ignoring evidence showing ‘‘the knowledge and perspective of one of ordinary skill in the art, the Board failed to account for critical background information that could easily explain why an ordinarily skilled artisan would have been motivated to combine or modify the cited references to arrive at the claimed inventions.’’ Id.
From Norgren Inc. v. Int’l Trade Comm’n, 699 F.3d 1317, 1322 (Fed. Cir. 2012) (‘‘A flexible teaching, suggestion, or motivation test can be useful to prevent hindsight when determining whether a combination of elements known in the art would have been obvious.’’); Outdry Techs. Corp. v. Geox S.p.A., 859 F.3d 1364, 1370–71 (Fed. Cir. 2017) (‘‘Any motivation to combine references, whether articulated in the references themselves or supported by evidence of the knowledge of a skilled artisan, is sufficient to combine those references to arrive at the claimed process.’’). In keeping with this flexible approach to providing a rationale for obviousness, the Federal Circuit has echoed KSR in identifying numerous possible sources that may, either implicitly or explicitly, provide reasons to combine or modify the prior art to determine that a claimed invention would have been obvious. These include ‘‘market forces; design incentives; the ‘interrelated teachings of multiple patents’; ‘any need or problem known in the field of endeavor at the time of invention and addressed by the patent’; and the background knowledge, creativity, and common sense of the person of ordinary skill.’’ Plantronics, Inc. v. Aliph, Inc., 724 F.3d 1343, 1354 (Fed. Cir. 2013), quoting KSR, 550 U.S. at 418–21, 127 S. Ct. at 1741–42.
The Federal Circuit has also clarified that a proposed reason to combine the teachings of prior art disclosures may be proper, even when the problem addressed by the combination might have been more advantageously addressed in another way. PAR Pharm., Inc. v. TWI Pharms., Inc., 773 F.3d 1186, 1197–98 (Fed. Cir. 2014) (‘‘Our precedent, however, does not require that the motivation be the best option, only that it be a suitable option from which the prior art did not teach away.’’) (emphasis in original). One aspect of the flexible approach to explaining a reason to modify the prior art is demonstrated in the Federal Circuit’s decision in Intel Corp. v. Qualcomm Inc., 21 F.4th 784, 796 (Fed. Cir. 2021), which confirms that a proposed reason is not insufficient simply because it has broad applicability. Patent challenger Intel had argued in an inter partes review before the Board that some of Qualcomm’s claims were unpatentable because a PHOSITA would have been able to modify the prior art, with a reasonable expectation of success, for the purpose of increasing energy efficiency. Id. at 796–97. The Federal Circuit explained that ‘‘[s]uch a rationale is not inherently suspect merely because it’s generic in the sense of having broad applicability or appeal.’’ Id. The Federal Circuit further pointed out its pre-KSR holding ‘‘that because such improvements are ‘technology independent,’ ‘universal,’ and ‘even common-sensical,’ ‘there exists in these situations a motivation to combine prior art references even absent any hint of suggestion in the references themselves.’ ’’ Id., quoting DyStar Textilfarben GmbH v. C.H. Patrick Co., 464 F.3d 1356, 1368 (Fed. Cir. 2006) (emphasis added by the Federal Circuit in Intel). When formulating an obviousness rejection, the PTO may use any clearly articulated line of reasoning that would have allowed a PHOSITA to draw the conclusion that a claimed invention would have been obvious in view of the facts. MPEP 2143, subsection I, and MPEP 2144. Acknowledging that, in view of KSR, there are ‘‘many potential rationales that could make a modification or combination of prior art references obvious to a skilled artisan,’’ the Federal Circuit has also pointed to MPEP 2143, which provides several examples of rationales gleaned from KSR. Unwired Planet, 841 F.3d at 1003.
When considering the prior art in its entirety, note Allied Erecting v. Genesis Attachments, 825 F.3d 1373, 1381, 119 USPQ2d 1132, 1138 (Fed. Cir. 2016) ("Although modification of the movable blades may impede the quick change functionality disclosed by Caterpillar, ‘[a] given course of action often has simultaneous advantages and disadvantages, and this does not necessarily obviate motivation to combine.’" (quoting Medichem, S.A. v. Rolabo, S.L., 437 F.3d 1157, 1165, 77 USPQ2d 1865, 1870 (Fed Cir. 2006) (citation omitted))). However, "the prior art’s mere disclosure of more than one alternative does not constitute a teaching away from any of these alternatives because such disclosure does not criticize, discredit, or otherwise discourage the solution claimed…." In re Fulton, 391 F.3d 1195, 1201, 73 USPQ2d 1141, 1146 (Fed. Cir. 2004).
The pending claims are treated on the merits below to the extent they are understood and considered definite.
Claims 1, 2, 3, 6, 7, 8, 9, 10, 11, and 12 are rejected under 35 U.S.C. 103 as being unpatentable over DE 102014104050 A1 in view of WITTKOP et al. (US 5131818).
DE 102014104050 discloses a high pressure homogenizer (2, see figure 1) for free-flowing substances loaded with particles, with a high pressure chamber (14), and a homogenizing unit (76) which is connected fluidically downstream thereof and expands the fluid to be homogenized, which fluid has previously been brought to a high pressure in the high pressure chamber (14}, with swirling of the fluid, and a plunger pump (4) which is assigned to the homogenizing unit (16) and the plunger (28) of which pressurizes the high pressure chamber (14), wherein the high pressure homogenizer (2) has a low pressure chamber (12) for cooling the plunger (28), which low pressure chamber (12) surrounds the plunger shaft and has a lower operating pressure, wherein the low pressure chamber (12) and the high pressure chamber (14) are separated from one another by a seal (18) which is penetrated by the plunger (28). DE ‘050 does not necessarily disclose that the seal is a throttle gap which is configured between the plunger shaft (6) and a bushing (9) which does not make contact with the plunger shaft and the recited S/L ratio to provide a suitable gap between the plunger and bushing.
More specifically, DE ‘050 discloses a homogenizing device for fluid substances with at least one homogenizing unit (16) and a piston pump device associated with the homogenizing unit (16) is intended to enable a particularly reliable operation of the device. For this purpose, the invention provides that the piston pump device has a high-pressure chamber (14) and a low-pressure chamber (12), wherein the high pressure chamber (14) for an operating pressure of PH> 100 bar and the low pressure chamber (12) is provided for an operating pressure of PN <PH and wherein the low-pressure chamber (12) is assigned as a cooling device to the piston (28) of the piston pump device. The invention relates to a homogenizing device for fluid substances with at least one homogenizing unit and a piston pump device associated with the homogenizing unit, as well as a piston pump device with a sealing arrangement and a cooling system for a homogenizer.
When homogenizing, the size of the drops in an emulsion or the particles in a suspension is reduced in order to make them as homogeneous as possible or equal to each other. For this purpose, the homogenizing device comprises a homogenizing unit and a pump device. The product to be homogenized is pressurized by means of the pumping device and transported through a nozzle or a small opening or gap where it impinges on an opposite surface at high speed. The occurring impact and shear forces essentially cause the homogenization process achieved.
As pump devices usually one or more piston pumps are used during homogenization. These have a high-pressure chamber can flow into the product, which is again pressed out by a pump piston under high pressure from the high pressure chamber. In order to prevent product escaping from the high-pressure chamber into the pump housing, a high-pressure seal is arranged between the pump piston and the pump housing. From the prior art pump devices are known in which a plurality of piston pumps are interconnected to increase the power.
For an effective homogenization process, it is necessary that always a sufficiently high operating pressure is generated and made available. Since, during operation of the pump device, generally the heating of the pump and in particular of the pump piston occurs, there is the risk that components of the pump overheat, thereby reducing the performance of the pump device. Also, any leakage occurring in the area of the high-pressure seal can adversely affect the performance of the pump by passing product into the pump housing outside the high-pressure chamber. It would therefore be desirable to have a pumping device in which a heating of the pump piston is counteracted in a suitable manner and cannot lead to an impairment of the pump performance in the event of any leaking product.
The homogenizer is associated with a piston pump device having a high pressure and a low-pressure chamber, wherein the high pressure chamber for an operating pressure of > 100 bar and the low pressure chamber for an operating lower pressure and wherein the low-pressure chamber is assigned as a cooling device to the piston of the piston pump device. The operating pressure is to be understood as meaning a homogenizing pressure prevailing in the high-pressure chamber when the product is ejected.
By cooling the pump device, the homogenization process can be improved and the cooling fluid could fulfill an additional cleaning function by a suitable flow on the pump piston. On the other hand, however, the cooling should also take place via a closed cooling circuit, so that the cooling fluid does not simply drain off and has to be collected in a complex manner, as usual in practice. In the homogenization of liquids but could also be used for this purpose, the starting material as a coolant. Cooling is achieved by cooling the pump piston with the aid of the low-pressure chamber, whereby the power does not change significantly during the operation of the pump due to the occurrence of heat generation, since heat is removed from the pump piston by flowing a cooling fluid through the low-pressure chamber. The low-pressure chamber is preferably arranged near the high-pressure chamber. Characterized in that the pressure in the high-pressure chamber is greater than the pressure in the low-pressure chamber, contamination of the product by the cooling fluid can be prevented. Maybe in the low-pressure chamber penetrating product is transported away with the coolant and thus occurs as far as possible no contamination of the piston pump device.
A high-pressure sealing arrangement is provided for a spatial separation of the high-pressure and the low-pressure chamber, and the low-pressure chamber also has a low-pressure sealing arrangement delimiting it. The low-pressure chamber is characterized as seen in the axial direction in its length by the high-pressure sealing arrangement on the one hand and the low-pressure seal arrangement on the other hand, with the low-pressure chamber connects directly to the high-pressure chamber and both chambers are hermetically separated by the high-pressure sealing arrangement. For a particularly effective cooling, the low-pressure chamber encloses the piston of the piston pump device, in particular the low-pressure chamber is essentially formed by the pump housing surrounded by the pump piston and the pump piston. This ensures that the cooling fluid is in direct contact with the pump piston, whereby the cooling and cleaning effect can be improved.
In a piston pump device having a plurality of piston pumps, for a simple construction, the low-pressure chambers may be connected in parallel or in series.
Preferably, the pump housing is designed in several parts and the pump piston has a reduced diameter piston end, wherein at least one housing part on the connection side has an open recess for receiving a high pressure seal arrangement whose opening is equal to or greater than the high pressure seal assembly, in particular equal to or greater dimensioned a nominal diameter of the high pressure seal arrangement and a housing part is associated with a low-pressure seal, which defines a cooling chamber designed as a low-pressure chamber between the pump housing and the pump piston together with the high-pressure seal in the axial direction.
By the pump housing is formed in several parts, preferably in two parts, the high-pressure seal assembly can be inserted into the recess provided, characterized in that the recess is introduced at a separation point and has an extended opening for easy installation of the seal assembly. The recess may be incorporated in only one housing part or in both housing parts at the separation point. Due to the extended opening at the separation point assembly of the high-pressure seal assembly without deformation of the sealing elements is particularly easy.
Preferably, the pump piston is made of a ceramic material, more preferably of a ceramic material having a high thermal conductivity. The resulting during operation of the piston pump device heat can be dissipated even better.
In order to prevent any product from entering the low-pressure chamber, the surface of the pump piston preferably has a low roughness, in particular a low core roughness. Due to the low roughness, less product can deposit on the surface of the pump piston in depots, whereby less product is transported from the high-pressure chamber in the low-pressure chamber, which can dissolve there again from the pump piston and lead to contamination. Preferably, the pump piston may be polished.
In another preferred embodiment, the surface of the recess for the high-pressure seal assembly is hardened or provided with a wear resistant surface and polished. This ensures that, in particular, the sealing elements of the high-pressure sealing arrangement do not damage the surface of the recess by a reciprocating movement. This movement can be caused by the movement of the pump piston, which is in contact with the at least one sealing element or by the pressure differences between the high pressure and the low-pressure chamber.
For sealing the high-pressure chamber, preferably a sealing arrangement is used, with at least one radially sealing U-ring and an axially adjoining high-pressure-side sealing element, wherein the U-ring for receiving a radially acting spring element is open to the high-pressure side sealing element. The U-ring forms two sealing edges, which are pressed by means of the spring element against the surface of the recess and the piston and thus the high-pressure chamber is sealed product side. By using the spring element, it is not necessary in particular that the sealing groove ring is permanently elastic.
The high-pressure-side sealing element is formed from an elastic material or a spring with a low axial rigidity relative to the grooved ring. Occurring movements of the sealing elements are reduced by the high-pressure side sealing element is preferably under axial bias. It is proposed that the high-pressure side sealing element be designed in such a way that contact with the radially acting spring element is avoided. For example, by the high-pressure side sealing element is annular and the annular cross-section is small enough not to collide with the spring element. With a larger annular cross section, the high-pressure side sealing element may be provided for this purpose with a recess. Preferably, the sealing element is an axial spring, in particular a sinusoidal spring.
The high-pressure side sealing element is designed and configured such that its axially acting support force is greater than an axial force acting on the sealing arrangement on the low pressure side and preferably also greater than an axial friction force acting through the pump piston or the sum of the two forces. Movements of the seal assembly by pressure and friction and thus a local adverse change in the surface of the formed as a seal receiving recess, in particular in the region of the sealing edge, can be counteracted. The support effect is created by the high-pressure side sealing element is axially biased and the U-ring can be supported on this sealing element.
For cooling the piston pump device, for example, a cooling system with a closed cooling circuit is proposed, in which the cooling takes place via a cooling chamber, wherein the coolant pressure is lower than the homogenization pressure. On the one hand, this prevents that cooling fluid from the cooling circuit can enter the product circuit and, on the other hand, in addition to a high-pressure seal arrangement which seals the high-pressure chamber with respect to the low-pressure chamber, a relatively inexpensive seal can be used on the low-pressure side.
Basically, a feed device and/or a throttle arrangement is proposed for the promotion of the product in the high pressure chambers, in which a feed pressure for the high pressure chamber is generated, which should not be smaller than the refrigerant pressure in the low pressure chamber. The feed pressure should in particular be such that the pressure in the low-pressure chamber is always less than or equal to a pressure prevailing in the high-pressure chamber. As a result, it can be effectively prevented that, when the pump piston is driven back, coolant can penetrate into the pump housing, in particular into the high-pressure chamber. This is important, for example, when cooling with a separate coolant and not with the product. A cooling system has proved to be advantageous in which the cooling takes place by means of a product flow in that the piston pump device has at least one low-pressure and one high-pressure chamber and in which the cooling takes place by means of product flow as the coolant, the pressure chambers being coupled to one another.
For example, the product is taken from a product supply and fed via a pump preferably first low pressure chamber of the piston pump device. Subsequently, the product is conveyed into the high-pressure chambers and homogenized in the homogenizing unit. Conversely, the product as coolant can first be supplied to the high-pressure chamber and then only to the low-pressure chamber. A disadvantage of this design, however, is a heating of the product and thus the coolant, which is why a low-pressure chambers upstream cooling device may be required. In a preferred variant, the product is taken from a product supply and fed via the pump at least partially parallel to the high-pressure chamber of the low-pressure chamber.
It is further preferred to provide a cooling system with two adjacent low-pressure chambers, wherein the first low-pressure chamber for the coolant flow and a second low-pressure chamber for flowing through with a cleaning agent is provided. This ensures that on the one hand the cooling of the piston pump device can be done in a simple manner by means of product cooling and on the other hand counteracted by the cleaning process of a deposition of product. The pump piston is additionally cooled by the cleaning fluid.
The homogenizer according to the invention, which has a high-pressure chamber and a low-pressure chamber as cooling chambers, is suitable for allowing a leakage flow. This is made possible by a product cooling through the low-pressure chamber, since it is only supplied with additional product in the event of leakage and is thus collected. In the case of cooling with a product as coolant, not only can a comparatively high leakage flow be tolerated, it is also possible to configure the high-pressure seal arrangement such that a relatively high leakage flow is permitted. In this embodiment, it is considered advantageous that an additional cooling effect occurring thereby occurs, as a result of which the pump piston can be cooled even more effectively. Another associated advantage is a possible use of materials for the pump piston with a high degree of hardness and a comparatively low thermal conductivity. For example, materials such as zirconia, silicon nitride, silicon-aluminum oxynitride, cermet, yttria (Y2O3), mullite ceramics (Al6Si2O13), forsterite (Mg2SiO4), cordierite / iolite [(Mg, Fe) 2Al4Si5O18] or soapstone may be substantially disregarded their heat conduction properties are used for the manufacture or coating of the pump piston.
According to a preferred development, the homogenizing device, in particular the high-pressure sealing arrangement of a piston pump, is configured such that a leakage flow of 0.5 to 500 ml / h per piston pump is made possible. For example, a certain leakage flow can be adjusted by the design of the sealing elements takes place in dependence on the leakage current to be achieved.
A method for cooling a homogenizer, which has at least one piston pump with a high-pressure chamber and at least one designed as a cooling chamber low-pressure chamber, proposed via a closed cooling circuit, wherein the cooling of the pump piston in the low-pressure chamber by means of a fluid coolant takes place and a lipophilic emulsion or suspension is fed via the high-pressure chamber of a homogenizer unit as a product and cooled with a compatible with the product refrigerant. In the method of cooling, the refrigerant is compatible with the product up to 50% of the refrigerant in the product, or conversely up to 50% of the product in the refrigerant. Up to this mixing ratio, no reaction of the two substances should occur. In particular, no demixing, agglomeration or coalescence of the product and / or the coolant should occur. The coolant should not react with the product. It is proposed, especially when processing product in the non-aqueous solvent range, a coolant that forms no compounds together with the product used and to be homogenized, as this may damage the seals, for example. Particularly preferred is the use of ethanol as coolants since, as can be seen from the table, ethanol is compatible with all other listed substances. In addition, ethanol is relatively inexpensive, has a disinfecting effect and is basically non-toxic.
The advantages achieved by the invention are in particular that the reliability and reliability of the homogenizer can be improved by the inventive cooling of the piston pump device, characterized in that during operation of the device effectively dissipates heat while preventing contamination of the piston pump device by the product or at least is minimized.
Figure 1 shows a cooling system 2 for a piston pump 4 a homogenizer, which a product reservoir 6 for a fluid starting product and a product collecting container 8th for the final product, wherein the starting product by means of a feed pump 10 to the piston pump 4 is transported and first by a designed as a cooling device low-pressure chamber 12 then flows around a high pressure chamber 14 to be fed. About the high pressure chamber 14 the starting material to be homogenized flows into a homogenizing unit 16 and flows into the product catcher.
The piston pump 4 is formed of a two-part housing, wherein the housing division at the location of a high-pressure sealing arrangement 18 is executed. The housing parts 20 , 22 are detachably connected together so that the high-pressure seal arrangement 18 in disassembled state of the piston pump 4 can be used. For this purpose, the housing part 20 for the high-pressure chamber 14 a recess 24 with an expanded opening, not shown here. At the opposite end of the housing part 22 is for the low-pressure chamber 12 a low-pressure seal 26 arranged, which is the low-pressure chamber 12 together with the high-pressure seal assembly 18 axially limited. The low-pressure chamber 12 is essentially through the housing part 22 and a pump piston 28 educated. The piston pump 4 has an inlet valve 30 and an exhaust valve 32 for the high-pressure chamber 14 and the pump piston 28 has a reduced diameter piston end portion 34 which is in the high-pressure chamber 14 protrudes. The pump piston 28 leads during operation of the piston pump 4 by means of a drive device, not shown here, a linear movement, whereby the starting product under high pressure of a homogenizing unit 16 is supplied.
To achieve a high thermal conductivity and a low wear, there is the pump piston 28 from the ceramic material SISIC. This material consists of about 85 to 94% of SiC (silicon carbide) and 15 to 6% of metallic silicon.
A section of a piston pump 4 with a multi-part pump housing without illustrated high-pressure chamber housing is in 2 shown. In the area of the high pressure sealing arrangement, not shown in this figure, the housing is divided, which together with the low pressure seal also not shown here and the pump piston 28 the low pressure chamber 12 forms. The housing part for the high-pressure sealing arrangement is provided with a recess 24 provided, which has an extended opening. After insertion of the high-pressure seal arrangement in the recess formed as a seal receiver 24 , the housing part ( 22 ), which with a recess 36 for the low-pressure seal is fitted accurately. The housing parts 20 . 22 are by means of a ring seal 38 radial sealed. This causes the ends of the pump piston 28 with a chamfer 39 are provided, thereby reducing the diameter end, the piston 28 be particularly easily introduced into the two-piece pump housing, without damaging the high-pressure seal assembly.
In the low-pressure chamber 12 open an inlet channel 40 and an exhaust duct 42, via the inlet E, so the coolant in the low-pressure chamber 12 along the pump piston 28 flow and exit via the outlet A again. The distance between the pump housing 22 and the piston 28 is kept low, creating a cooling chamber volume 44 , in particular a flow cross-section of the low-pressure chamber 12 , is reduced. This increases the flow velocity, which results in a turbulent flow and, for example, leads to an improved cooling effect. A section of the piston pump 4 with a high-pressure seal arrangement 18 in a sectional view. In the recess 24 for the seal arrangement 18 is a guide bush 46 arranged and as a sealing element a U-ring 48 with one as ring 50 formed radially acting spring element, which is a high-pressure side sealing element 52 is open. The guide bush 46 consists of the high-performance plastic polyetheretherketone (PEEK) with a high radial stiffness and has comb-like depressions on the piston side 53 in which abrasion can accumulate. To the guide bush 46 closes the U-ring 48 made of polytetrafluoroethylene (PTFE), which in each case has a sealing edge 54 to the housing 20 and pump piston 28 axially seals. This is in the groove of the rings 48 the spring ring 50 used the sealing edges 54 pushes radially outwards and ensures a reliable seal. Finally, the high-pressure side is designed as an axial spring sealing element 52 polyurethane (PU) arranged with one opposite the U-ring 48 lower axial stiffness. The axial spring 52 is dimensioned so that the spring ring 50 not with the axial spring 52 collided. The entire high pressure seal arrangement 18 sits axially biased in the recess 24 of the housing part 20 , causing axial movements of the sealing elements 48, 50, 52 be reduced and thereby the life of the high-pressure seal assembly 18 elevated.
A multi-part piston pump device with three parallel piston pumps 4 shown at the low-pressure chambers 12 in a separate cooling circuit 55 are connected in series. The low-pressure chambers 12 are like in 2 represented by two housing parts 20 . 22 formed, wherein the separation of the housing in the region of the high-pressure seal arrangement 18 , between the low-pressure chamber 12 and the high-pressure chamber 14 is done so that in a first housing 20 the high-pressure seal arrangement 18 and in a second housing 22 the low pressure seal 26 is introduced.
The housing parts 20, 22 are on a third common housing part 56 mounted, causing the high-pressure chambers 14 the pump device are formed. In the high-pressure chambers 14 each lead to a product inlet channel 58 and a product outlet channel 60 with an inlet valve 30 and an exhaust valve 32 , The product is introduced via an inlet E of the piston pump device by means of a feed pump 62 in the high-pressure chambers 14 promoted and then under high pressure from where it then exits through an outlet A from the device again.
The cooling circuit 55 includes a feed pump 10 for a cooling fluid as a coolant, an adjustable throttle 64 and a refrigerated coolant tank 66 , The setting of a volume flow is basically only possible by a controllable or controllable feed pump without throttle. The coolant is added to the tank 66 , which also serves as a heat sink, by means of the feed pump 62 taken and through the low-pressure chambers 12 promoted.
A piston pump device analogous to 4 comprising three parallel piston pumps 4 each with a low-pressure chamber 12 , which are coupled in series with a product stream, is in 5 shown. The cooling of the piston pumps 4 takes place in this embodiment but by means of the product stream. The product flow is first through the high-pressure chambers 14 and then via the low-pressure chambers 12 guided. The pump device also includes a feed pump in this cooling system 62 for the high-pressure area and a feed pump 10 for the low-pressure area. In this embodiment, it is considered advantageous that already homogenized product is used for cooling, since the size of the particles in the coolant is smaller than in the starting product. Because the product heats up as a result of the homogenization process, the coolant cooling circuit is a cooler 68 provided as a heat sink. As with the in 4 shown embodiment, for an advantageous pressure adjustment in the low-pressure chambers 12 , the cooling circuit an adjustable or controllable throttle (not shown) associated with this cooling system 2 the low-pressure chambers 12 can be advanced or downstream.
Figure 6 shows a piston pump device as an embodiment with a cooling system 2 shown, in which the cooling takes place by means of product comprising three parallel piston pumps 4 each having a low pressure chamber, which are coupled in series with a product stream, wherein the product flow is first passed through the high pressure chambers and then via the low pressure chambers and a cooling volume flow via throttles 64a, b is adjustable. In an alternative variant, but also only one throttle 64a, b be designed as an adjustable throttle to adjust the cooling flow rate can.
Another variant of product cooling shows both product flow first via the low-pressure chambers 12 and then over the high-pressure chambers 14 is guided. The cooling system 2 has only one feed pump 10 for product promotion, with the product being the refrigerant first, the low-pressure chambers 12 flows through and then into the high-pressure chambers 14 is encouraged. The low-pressure area and the high-pressure area are connected in series and between the areas is an adjustable throttle 64 for pressure adjustment in the low-pressure chambers 12 arranged.
A cooling system 2 in which the cooling also takes place by means of a product stream 8th , wherein the product is additionally conveyed via a bypass in the high-pressure chambers. In this embodiment, the flow rate for the cooling of the pump piston 28 over the throttle 64a be set. The advantage here is that regardless of the supply of high-pressure chambers 14 over the throttle 64b can be adjusted.
The piston pump device in 9 corresponds to the structure of the pump device as in the 4 to 7 shown and the cooling of the piston pumps 4 takes place analogously 5 to 7 exclusively about the product. The high pressure area and low pressure area are connected in parallel and the cooling system 2 includes only one feed pump 10 as well as an adjustable throttle 64 for flow regulation in the low-pressure chambers 12 , The product is made by means of the feed pump 10 at the same time in the high-pressure chambers 14 and in the low-pressure chambers 12 promoted, which also serves as a coolant product after passing through the low-pressure chambers 12 is directed back into a product reservoir (not shown). The reservoir with the starting product serves as a heat sink for the cooling circuit 2 ,
The device is specifically designed for effective cooling of the pump device of a homogenizer. The cooling system 2 enables low-wear operation of the device by selecting suitable materials, surfaces and the design of the piston pumps 4 , In addition, due to the closed cooling circuit 2 or the use of product for cooling, which improves hygiene and reduces maintenance. By the construction according to the invention of the piston pump device with a high-pressure sealing arrangement 18 from the high-pressure chamber 14 spatially separated low pressure chamber 12 will provide effective cooling of the pump piston 28 permitting a permissible leakage flow through the high-pressure seal assembly 18 can further improve the cooling effect.
WITTKOP et al. discloses a high-pressure pump with a plunger 4 movable within a bushing 2; a sealing arrangement including a throttle gap “d” between the plunger 4 and the bushing 2 of the recited size (col. 7, lines 51-55); the bushing 2 does not contact the plunger 4 by virtue of the throttle gap “d”. Seals of this type are suitable for high pressure pumps, since a part of the displaced liquid is pressed as cooling medium into the gap (column 4, lines 12-42); wherein the cylindrical length of the throttle gap “d” is equal to at least ⅔ of the diameter of the plunger and ideally corresponds at least to the entire diameter of the plunger 4 - Figure 2; wherein the annular gap height “d” of the throttle gap is equal to a maximum of 0.03 mm (col. 7, lines 51-55); wherein the bushing 2 and the plunger 4 are constructed of materials with different heat expansion coefficients (col. 4, lines 12-55); wherein the material of the bushing (thermoplastic synthetic resin” is softer than the material of the plunger (formed of metal) - col. 6, lines 12-66; wherein the plunger 4 is configured in such a way that the longitudinal axes of the bushing 2 and of the plunger 4 moving back and forth in the bushing 2 are consistently aligned parallel or preferably coaxially, wherein the plunger 4 at the same time is a movable drive piston - Figure 2; the bushing 2 is held in the radial direction essentially rigid in the housing portion 1, 3 surrounding it and the plunger—by means of a radially flexible coupling 19 that is capable of preventing transmission of pivotal motions; wherein the bushing 2 is held in the radial direction more than to an insignificant extent in the housing portion 1, 3 surrounding it and the plunger 4 in a radial direction is connected rigidly with the drive piston 20 that powers it; wherein the front end of the drive piston 20 transmitting drive pressure forces onto them has a surface that is curved convexly (Figure 1).
More specifically, WITTKOP et al. discloses a high-pressure water pump of the reciprocating piston type has its metal piston reciprocatable in a cylinder bushing composed of PEEK base high-strength thermoplastic synthetic resin and constructed so as to define a cooling clearance between the piston and the cylinder designed to prevent the temperature of the bushing on continuous operation from rising above 100.degree. C. The piston shoe and the slide bearing for the eccentric shaft should also be a PEEK based resin which can have a filler of carbon fibers, PTFE, glass fibers and/or mineral. A high-pressure water pump of the type in which a metallic piston is reciprocated in a cylinder by an eccentric on an eccentric shaft journaled in the cylinder housing and of the type in which the water is drawn into the pump through an inlet to an eccentric chamber in which the eccentric is rotated, is supplied from the chamber to the cylinder compartment between the piston and the cylinder head, and is displaced past a discharge valve to an outlet port on the housing.
High-pressure water pumps which utilize piston and cylinder arrangements are known and the type of high-pressure water pump with which the present invention is concerned comprises at least one cylinder, a cylinder bushing or sleeve within this cylinder, a cylinder head, a metal piston reciprocatable in the cylinder bushing and a piston shoe on the piston and engageable with an eccentric carried by an eccentric shaft journaled in an eccentric shaft housing.
The pump further comprises intake and outlet valves with valve closure members and the piston guide shoe operatively connects the piston with the eccentric so that upon rotation of the eccentric shaft, the eccentric will reciprocate the piston to alternately expand and contract the cylinder compartment or chamber defined between the piston and the cylinder head in the cylinder bushing During an intake stroke, corresponding to expansion of the cylinder chamber, a low pressure is developed in the cylinder chamber and water is drawn from the eccentric shaft compartment into the cylinder chamber During the succeeding stroke, namely the discharge stroke, the volume of the cylinder chamber is contracted and the water is forced under high pressure from the cylinder chamber.
To supply the water, a low-pressure reservoir is generally provided and can be connected to the housing by an appropriate flange communicating between the eccentric shaft compartment and the low-pressure water reservoir. For the purposes of this application, low pressure means a water pressure of 10 bar or less. The water is drawn out of the eccentric shaft compartment via at least one intake valve during the intake stroke into the cylinder chamber. The intake valve opens when the water pressure in the cylinder chamber is below the low pressure of the reservoir by a predetermined low-pressure threshold. If the pressure difference is smaller than the low pressure threshold or with an opposite sign, the suction valve is closed. During the displacement stroke, the water in the cylinder chamber is compressed at high pressure. For the purposes of this application, the term high pressure means a water pressure of, for example, 60 bar to 450 bar. The outlet valve opens as a rule at a selectable high-pressure threshold of the water pressure, which corresponds to the desired minimum high-pressure level. Below this high-pressure threshold, the outlet valve is closed. Upon exceeding the high-pressure threshold during the displacement stroke, the outlet valve opens to permit the displaced water to flow to the outlet port of the housing under high pressure.
The kinematics of the piston movement is such that the piston has a so-called upper dead point and so-called lower dead point The stroke of the piston is established by the rotation of the eccentric which is coupled to the piston by the piston guide shoe which pushes the piston toward the upper dead point position or allows the movement of the piston, e.g. under spring force, into the lower dead point position. A spring can therefore retain the shoe of the piston against the eccentric.
The piston can be guided, in its lower dead point position, over its entire length in the cylinder bushing or can have a portion of the piston turned toward the eccentric shaft which is withdrawn from the cylinder bushing in its lower dead point position. If the piston and cylinder bushing are of the same length, the piston in its lower dead point position is guided in the cylinder bushing over a length which is equal about to the difference between the length of the cylinder bushing and the piston stroke. In any event, the piston and cylinder bushing should be dimensioned with respect to their lengths and the stroke such that detrimental canting of the piston does not occur in operation.
In high-pressure pumps, both the piston and the cylinder bushing were composed of metallic materials. A clearance was frequently defined between the piston and cylinder bushing which would allow sliding of the piston in the cylinder bushing at the operating temperature range. In other words at the operating temperature, with thermal expansion, the tolerance was such that the piston was not permitted to seize in the cylinder. The length over which the piston is guided in the cylinder could be defined as the gap length.
In high-pressure water pumps, the water which is displaced has functional significance for the operation of the pump. On the one hand, the high-pressure pump is continuously cooled by the water flow through it. On the other hand, the displaced water also performed a lubricating function since it generally carried a lubricant along with it. Free slidable surfaces of the pump were continuously wetted with the lubricant carried by the water. Indeed, lubricant content of the water could be as much as 5%, although lesser lubricant contents could be used.
When both the piston and the cylinder bushing were composed of metal, a minimum lubrication was essential. Should the supply of lubricant to these surfaces be reduced below the necessary minimum, the temperature of the cylinder bushing and the piston would rise because of increased friction and in spite of the above-mentioned cooling effect. With increased friction, there was increased wear of material from the piston and/or the bushing which resulted in increasing detriment to the function of the high-pressure water pump. In practice it was found that the conventional high-pressure water pumps, operated without the addition of lubricant to the water, had a relatively short life and rapidly deteriorated for the reasons given above. However, the lubricants used were detrimental to the environment if the displaced water was not conducted in a closed path.
When high-pressure water is used, a closed path for the water is impossible or, at best, is extremely expensive. In other words, lubricant addition is undesirable on environmental grounds but is a practical necessity on technological grounds for effective operation of the high-pressure water pump. Provided is a high-pressure water pump of the type generally described above but which has an improved useful life even with continuous operation and which can be operated without the addition of lubricants to the water, i.e. for the displacement of pure water if desired.
The cylinder bushing is of a material selected from the group of high-strength thermoplastic synthetic resins on a polyetheretherketone basis, and further such that the all-around clearance or gap between the piston and the cylinder bushing is dimensioned to form a cooling gap through which a portion of the displaced water is forced as a cooling medium The gap is dimensioned so that this by-passed portion of the flow serving as the cooling medium for the gap, in continuous operation of the pump prevents the temperature of the cylinder bushing from exceeding 100.degree. C. and most preferably, from exceeding 50.degree. C.
The high-pressure water pump of the invention can comprise a housing defining an eccentric-shaft compartment, a cylinder and a cylinder head; an eccentric shaft journaled in the housing and having an eccentric in the compartment; a cylinder bushing composed of a high-strength polyetheretherketone thermoplastic synthetic resin in the cylinder; a metal piston slidable in the cylinder bushing; a piston-displacement shoe operatively connected to the piston and engaging the eccentric whereby the piston is reciprocated in the cylinder bushing upon rotation of the eccentric shaft; and intake and outlet valves enabling water to be drawn in an intake stroke of the piston into a cylinder chamber defined in the bushing between the head and the piston from the compartment and water to be driven from the pump at high pressure from the cylinder chamber in a discharge stroke of the piston, the piston defining an all-around clearance with the cylinder bushing through which a portion of water driven from the chamber is forced as a cooling medium, the all-around clearance having a gap width selected to define a minimum volume rate of flow of the cooling medium sufficient to maintain a maximum temperature of the cylinder bushing of 100.degree. C. in continuous operation.
Lubricant-free water is water that need not have lubricants added to it for the purposes of lubricating the pump. Slight contamination of the water can occur, for example, via units provided upstream of the high-pressure water pump and which cannot be avoided. Nevertheless the pump permits water with a high degree of purity to be displaced and it permits the system to be used for monitoring purity of water if desired or in conjunction with a system for monitoring the purity of the water.
The combination of metal with a high-strength thermoplastic polyetheretherketone based synthetic resin for the piston and cylinder bushing allows continuous operation in a lubricant-free manner in the high-pressure pump when the clearance, tolerance or gap is provided as a coolant flow gap through with a portion of the displaced water can flow as a cooling medium. The advantages of the material pair in the tribological sense are utilized while the drawback of the low thermal conductivity of the nonmetallic body is overcome by augmenting the heat transfer by forcing a partial stream of water through the gap. High-strength thermoplastic materials of the polyetheretherketone type satisfy the mechanical requirements.
The cooling efficiency which is determined by the size of the clearance and thus the volume rate of flow of the water through it is a function of the pressure difference between the water pressure in the cylinder chamber and the water pressure in the eccentric shaft compartment, the width of the gap and the length of the gap. The gap length is usually determined by structural considerations. The gap width, therefore, can be adjusted so that a maximum permitted temperature developed at the bushing is 100.degree. C. In practice it turns out that the amount of high-pressure water which is by-passed as the cooling stream is so small that the pump function of the high-pressure pump is not detrimentally effected.
While the cylinder bushing can be composed of a high-strength thermoplastic synthetic resin of the polyetheretherketone (PEEK) type without a filler, in a preferred embodiment of the invention, the cylinder bushing is composed of the PEEK-containing carbon fibers as a filler. Carbon fibers form a reinforcement of the material in the structural sense and improve the mechanical properties. The thermal conductivity is increased by the presence of the carbon fibers as well, thereby permitting the partial flow of cooling water to pass through the cooling gap to be reduced or minimized. Carbon fibers also have a graphitic structure in a microscopic sense and thus the graphite simultaneously contributes lubricating characteristics to the bushing or sleeve. The PEEK based high-strength thermoplastic synthetic resin can contain in addition or alternatively, polytetrafluoroethylene as a filler contributing lubricating properties. It is also possible to incorporate glass fibers or mineral fibers or both in the high-strength PEEK based material It should also be mentioned that with all embodiments, the high-strength thermoplastic PEEK based synthetic resin, with respect to its macroscopic properties, should have an isotropic appearance. According to a further feature of the invention, the material of the bushing is a high-strength thermoplastic PEEK based synthetic resin with a hardness of at least 110 on the Rockwell "M" scale. A higher hardness will reduce the rate of wear and ensure good dimensional stability of the cylinder bushing even with continued operation for length performance of time. The material of the bushing should have a thermal conductivity of at least 0.80 W/mK. Higher thermal conductivities reduce the volume rate of flow of the cooling medium which is required in the cooling gap to prevent the maximum temperature of the bushing to rising above 100.degree. C.
For optimum results, the ratio of the throttling gap width to gap length should be in the range of 0.0005 to 0.0007, when the ratio of the by-passed cooling medium flow to the total pump intake is 0.0002 volume % to 0.0003 volume %. It also has been found to be advantageous to provide the piston guide shoe of a high-strength thermoplastic PEEK base synthetic resin and to journal the eccentric shaft in slide bearing shells of this material and/or to provide this material as the material for the valve closure elements. The bearing shells can be formed in one piece as bushings or sleeves or they can be assembled from segments, i.e. multipartite shells. Of course, the materials used for the bearing shells, the valve members and the piston shoes can include fillers as described.
The high-pressure water pump of the invention can provide a plurality of cylinders in a row and the cylinders can be arrayed in a radial plane or in an axial plane. Other embodiments are conceivable as well in which a plurality of cylinders is provided although the pump can have a single cylinder if desired.
The high-pressure water pump of the invention has been illustrated in the form of a radial piston pump in FIG. 1 and in FIG. 1, a single cylinder 1 has been illustrated, and in FIG. 4, two cylinders 1 and 1' are shown to be provided in angularly-spaced relationship about the eccentric shaft whose eccentric is represented at 20. In the embodiment of FIG. 5, the two cylinders 1 and 1' have been shown to be axially spaced apart and each cooperates with a respective eccentric 20 and 20' on the common eccentric shaft.
It will be apparent from FIGS. 4 and 5 that any number of cylinders can be angularly spaced in a common radial plane (FIG. 4) or axially spaced in a common axial plane (FIG. 5) or that various arrangements can be provided in which cylinders and respective pistons are both axially and angularly spaced from one another about the axis of the eccentric shaft. The same principles as will be developed below apply to all such arrangements.
As can be seen from FIG. 1, each cylinder 1 (or 1') can receive a cylinder bushing 2 which is composed of a material from the group of high-strength thermoplastic synthetic resin of a polyetheretherketone base, i.e. a PEEK resin.
As is apparent from FIG. 3, the cylinder bushing 2 is cemented via an adhesive layer 2a in the cylinder 1. The cylinder is closed by a cylinder head 3 forming part of a pump housing to be described in greater detail hereinafter.
In the cylinder bushing 2, a piston 4 of metallic material is radially reciprocatable. The piston 4 is urged by a compression spring 19 in the direction of its lower dead point position. The compression spring 14 holds the piston 4 against a piston guide shoe 5 and the piston guide shoe 5, in turn, against a respective eccentric 20. The piston guide shoe is also composed of a material which is a high-strength thermoplastic PEEK based synthetic resin. The eccentric [drive piston] 20 forms part of an eccentric shaft 6. On both sides of the eccentric 20, the eccentric shaft is journaled in one piece bearing shells 7, i.e. so-called slide bearing or plain bearing shells which are composed of high-strength thermoplastic PEEK based synthetic resin. The bearing shells 7 journal the eccentric shaft in the eccentric shaft housing 8 which defines eccentric shaft compartment 14 surrounding the eccentric 20. The piston 4 defines with the cylinder head 3 within the cylinder bushing 2 a cylinder chamber 13. Between the piston 4 and the cylinder bushing 2, an all-around clearance 15 is provided with a gap width d (FIG. 3) and a gap length 1 (FIG. 1).
In the region of the cylinder head 3, an intake valve 9 is provided, this valve being constituted as a ring 11 of the high-strength PEEK-based synthetic resin which overlies a plurality of passages 30 connected via a space 31 surrounding the cylinder 1 with the eccentric compartment 14. The eccentric compartment 14 is connected via a port 16 in a flange 32 affixed to the housing 8 by bolts 33 and connected with a source of the water to be pumped.
Also in the region of the cylinder head 3, an outlet valve 10 is provided which includes a valve member 12 of the high-strength thermoplastic PEEK based synthetic resin, the latter being biased into a closed position via a spring 34. The valve members 11 and 12 are actuated by pressure differential during the intake and displacement strokes of the piston 4.
The discharge valve 10 opens into a passage 35 in a cylinder-defining portion 37 of the housing which is affixed to the housing part 8 having the passages 38 communicating with a passage 39 in the flange 32 with which, in turn, an outlet 17 communicates. Ports 40 can represent connections to other cylinders angularly spaced about the eccentric shaft.
During the intake stroke of the piston 4, i.e. the stroke in which the piston is biased radially inwardly by its spring 19 as the eccentric shaft 6 is rotated, the pressure in the chamber 13 falls below the pressure in the compartment 14 and water passes via the passages 13 and the valve 9 into the chamber 13. During the compression stroke, i.e. the stroke during which the piston 40 displaced radially outwardly by the eccentric 20, the valve 9 is closed by the increased pressure in the chamber 13 and valve 10 is forced open to drive the water at high pressure to the outlet 17. The valve 10 is closed during the intake stroke and valve 9 is closed during the discharge stroke. The valve 10 opens when the water pressure in the cylinder chamber 13 exceeds a high-pressure threshold as mentioned previously. The piston 4 and the eccentric shaft 6 can be formed with passages 21 and cooling bores at which these passages open toward the sliding surfaces of the shoe 5 and the bearing shells 7 to effect cooling of these regions.
The ratio d:l should be 0.0005 to 0.0007, the gap width d should be such that approximately 0.0002 to 0.0003 volume percent of the water displaced by the pump passes through the gap 15 as cooling water to maintain the temperature of the bushing 2 below 50 degrees C. The PEEK based material used can contain carbon fiber, PTFE, glass fiber, and/or mineral filler.
Accordingly, in view of the prior art teachings and 103 guidance above, it would have been prima facie obvious to one skilled in the art before the effective filing date of the invention to have provided the pump of DE ‘050 with the recited throttling gap and other related elements of WITTKOP et al. for the purposes of providing effective cooling of the internal components of the pump (plunger, bushing, etc.) to a desired temperature as explained above.
Claims 4, 13, 14, and 17 are rejected under 35 U.S.C. 103 as being unpatentable over DE 102014104050 A1 in view of WITTKOP et al. (US 5131818) as applied to claim 1 above and further in view of DE 2336147 A1.
Modified DE 102014104050 A1 does not disclose the bevel on the bushing, the bushing rings of different materials, and the bushing components are floating. DE 2336147 A1 discloses a high-pressure pump having a housing 10; a movable plunger 16 surrounded by a bushing configured as rings 8, 19, 20, 21, 22 that are arranged in a floating manner (per paragraph [0021] of the translation of record); the rings being formed of different materials per the different cross-hatching in Figure 1. The rings 19 and 20 have the recited end bevel 35 or 36 as seen in Figure 2.
It would have been obvious to one skilled in the art before the effective filing date of the invention to have modified the pump of DE ‘050 to include a plunger bushing in the form of floating rings and with a bevel on the bushing rings and the bushing rings formed of different materials as taught by DE ‘147 for the purposes of the sealing bushings being arranged floating on the piston, so that they exclusively fulfill a sealing function and have no guiding function for the piston and because the sealing sleeve can float freely on the piston, which can be facilitated by conical bevel surfaces at both ends of the sealing sleeve, very small sealing gaps can be achieved without the risk of the piston getting stuck in the sealing sleeves [0021] and such that a lubricating film is promoted in the throttling gap 31 for the piston/plunger [0059].
More specifically, DE ‘147 discloses a device for hydraulic piston sealing in high-pressure piston pumps, namely a device for hydraulic piston sealing in high-pressure piston pumps by a hydraulic piston sealing in high-pressure piston pumps that provides good sealing of the pistons even at high operating temperatures and a high piston movement frequency, even with low-viscosity liquids. A sealing bushing is arranged to float on the piston as a sealing body. Its inner side forms a sealing gap surface, for which a leakage rate is obtained. The leakage rate is proportional to the pressure, that the sealing gap width enters the equation to the third power, and that the leakage rate is inversely proportional to the length of the seal. The decisive criterion is therefore the width of the sealing gap, which must be chosen to be as small as possible and be able to maintain this small value. In the case of gap seals with fixed sealing elements, for example sealing elements clamped on one side, which are also used to support the piston, this requirement cannot be met, since the sealing surface of these sealing elements is exposed to wear from the piston.
In the device according to the invention, the sealing bushings are arranged floating on the piston, so that they exclusively fulfill a sealing function and have no guiding function for the piston. Because the sealing sleeve can float freely on the piston, which can be facilitated by conical surfaces at both ends of the sealing sleeve, very small sealing gaps can be achieved without the risk of the piston getting stuck in the sealing sleeves. A secure seal can be further improved by dividing the entire sealing body into several axially successive sealing bushings, all of which can adjust themselves radially to float on the piston. In this way, relatively long gap seals can also be produced, in which a uniform and small gap width can be maintained.
For high medium pressures, the sealing bushings can be advantageously exposed to the pressure of the operating medium from the outside, at least in sections.
This prevents the sealing bushings from swelling with a corresponding increase in gap height, and the sealing bushings can even be subjected to an external overpressure with a tendency towards a narrowing of the sealing gap. In this context, the sealing bushings can advantageously be pushed onto the piston with the surrounding cylinder housing, forming an outer annular gap accessible to the operating medium, and can also be expediently provided with a step on each end face, forming a radial annular gap communicating with the outer annular gap. This gradation achieves a partial compensation of the axial pressure acting on the sealing bushings, thereby further facilitating the radial adjustability of the sealing bushings. At the same time, the contact surfaces of the successive sealing bushings are reduced, which with their end-
surfaces or other external surfaces that are appropriately perpendicular to their longitudinal direction can create an axial seal, thereby eliminating the risk of the bushings tilting when the guide surface planes are not aligned.
A further advantageous embodiment of a piston sealing device designed according to the invention can be achieved by having at least one of the lateral sealing rings, between which the sealing bushing or the set of sealing bushings is arranged, rest on its side facing away from the sealing bushing against an intermediate body which consists of a material that swells under the influence of the operating medium.
This intermediate body automatically ensures a certain axial pressure during pump operation, which keeps the sealing bushing in contact with adjacent sealing bushings or the subsequent sealing rings. This intermediate body also facilitates the installation of the seals, as during installation only care needs to be taken to ensure that the sealing bushings are arranged with minimal axial play. This axial play is eliminated by the swelling intermediate body when the device is put into operation. Therefore, the sealing bushings will be pulled out of alignment by applying one-sided axial pressure during the installation of the seal. This is avoided, and the sealing bushings can adjust themselves smoothly on the piston. The swellable intermediate body can be assembled and dimensioned in such a way that a precisely predictable axial preload is achieved during commissioning.
At very high pressures, it is also advantageous to design the device according to the invention such that the swellable intermediate body is arranged between the closing ring and a closure ring body, which has both an inner and an outer circumferential groove for collecting leakage fluid and whose two circumferential grooves communicate with each other and with a drain channel leading to the suction side of the pumps.
This prevents leakage fluid from flowing outwards and returns the leakage fluid to the suction side of the cylinder/piston assembly. This also makes it easier to seal the entire cylinder unit against the unwanted ingress of air.
Fig. 1 shows in a schematic arrangement a section 10 of the cylinder part of a high-pressure piston pump with an intake channel 11 and a pressure channel 12, which are connected to a cylinder bore 15 via a suction valve 13 and a pressure valve 14 respectively. The rod-shaped piston/plunger 16 is mounted in the cylinder bore 15 and performs a reciprocating longitudinal displacement indicated by the double arrow 17. The piston is mounted in the area of its front end in a ring 18, which is inserted into the enlarged rear part of the cylinder bore 15 with a stop against the bore shoulder 19.
The device for sealing the piston/plunger 16 is also housed in this extended rear part of the cylinder bore 15. It consists of two identical sealing bushings 19 and 20, which are pushed one behind the other onto the piston 16, the construction of which is explained in more detail in conjunction with Fig. 2. The first sealing bushing 19 abuts with one end face against the bearing ring 18. The other sealing sleeve 20 is followed in an axial direction by a closing ring 21, which is followed by a closure ring body 22. The entire sealing device is held in the enlarged part of the cylinder bore 15 by means of a end plate 23 screwed to the cylinder part of the pump. On the closure ring body 22, an annular intermediate body 24 is arranged in conjunction with the closing ring 21. This intermediate body consists of a material that swells upon contact with the liquid operating medium and thereby automatically creates a certain axial preload in the cylinder bore, which holds the individual parts against each other and prevents axial movement.
A sealing sleeve 25 is inserted into the outer end face of the locking ring body 22, which prevents the ingress of air from the outside into the sealing device is prevented.
The escape of leakage fluid to the outside is prevented by an outer circumferential groove 26 and an inner circumferential groove 27 of the sealing ring body, which are connected to each other by transverse channels 28 and which communicate with a drain channel 29 formed in the cylinder part of the pump, which opens into the intake channel 11. The leakage fluid is drained away via these annular grooves 26 and 27 and the drainage channel 29.
As can be seen from the sectional view of Fig. 2, the sealing bushings 19 and 20, with their inner surface 30, define a narrow throttling sealing gap 31 with the piston 16.
On the end faces of the sealing bushings 19 and 20, the inner surface 30 transitions into a conical shell surface/bevel 35 or 36, which promotes the formation of a lubricating film in the throttling sealing gap 31 during the reciprocating movement of the piston/plunger 16. The sealing bushings 19 and 20 are provided on their end faces with a step 37 or 38 on the outside, by which the stop area 39 or 40 of the end faces is limited to a relatively narrow ring area with the advantages already mentioned at the beginning.
At the same time, radial annular gaps 41 are formed by these steps 37 or 38, which, according to Fig. 1, have circumferential annular gaps 42 are connected, which exist between the outer surface 43 of the sealing bushings 19 and 20 and the wall of the enlarged part of the cylinder bore and into which the pressure medium can enter, forming a partial pressure equalization.
Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over DE 102014104050 A1 in view of WITTKOP et al. (US 5131818) as applied to claim 1 above and further in view of BREIT (US 3902404).
Modified DE 102014104050 A1 does not disclose an outer enclosing surface of the bushing being spherical. BREIT discloses a high-pressure pump having a housing 11; a movable plunger 15 surrounded by a bushing 19 with a throttling gap 21 therebetween; the outer enclosing surface/sleeve 18 of the bushing 19 presenting a thickened spherical part at 18c - Figure 6.
It would have been obvious to one skilled in the art before the effective filing date of the invention to have provided the outer enclosing surface of the bushing in DE ‘050 alternatively with a spherical surface as taught by BREIT for the purpose of preventing compression of the sleeve to an extent such that no metallic contact between the relatively movable surfaces of sleeve 18 and of piston/plunger 15 can occur.
More specifically, the modification of FIG. 6 corresponds to the construction shown in FIG. 1, and corresponding parts are indicated by corresponding primed reference numerals. The cylinder block 11' has a bore 24' in which the piston means 15' is located. In a cylindrical recess 11a of the cylinder block 11', the sealing sleeve 18' with a bushing 19' is inserted in such a manner that the piston means 15' passes through sleeve 18', 19' in axial direction, while radially outward of sleeve 18' a control chamber 22' is formed in the recess 11a. The sealing gap 21' has, when there is no load on the machine, the same radial width along its length, which is preferably between 100mm. and several hundredth millimeters. The sealing sleeve 18' is fixedly inserted into the cylinder housing block 11', a sealing means 27 being provided for sealing the control chamber 22' at the end remote from the high pressure chamber. A screw cap 31' secures the sleeve 18' in axial direction.
In the same manner as described with reference to FIG. 1, the sealing gap 21' communicates through the bore 24' with the pump chamber, and by means of grooves 25' with the control chamber 22'. On the low pressure end, the sealing gap 21' is connected with outlet means 28', 29', which may freely open into the atmosphere, or connect with an air reservoir.
The sealing means 30' performs a stripping function and abuts without or with a low pressure, against the piston means 15'. The sealing means 30' may also be omitted if discharge of leakage fluid through the axial bore 28a is of no importance, and the leakage flow can be discharged instead of through the outlet 28, through the axial bore 28a.
The piston means 15' has an abutment member 36' with a spherical abutment face 37' which abuts, preferably with some axial play a, on a correspondingly shaped spherical seat 28a which is mounted on the drive member 16', for example, a cross head, for radial movement in all directions. Preferably the space 40' in which the abutment member 36' abuts the seat 38a, is filled with oil so that the parts can move with little friction relative to each other.
In order to further reduce the friction, the seat disc 38a can be mounted by means of balls or rollers 38b on a face of the cross head 16'.
It has been found that for obtaining the most favorable shape of the gap 21, the sleeve 18 must be formed in accordance with the prevailing pressure conditions. The constricted sealing sleeve 18 shown in FIG. 1 is suitable for comparatively low pressures, up to about 500 atms. When the pressure is higher, the depth of the constriction may be reduced, and when the pressure becomes very high, the sealing sleeve 18' may have a central portion, preferably closer to the low-pressure end, which is thicker than the end of the sleeve in the region of the high pressure chamber 13.
FIG. 8 shows schematically the profile outline of several modified sleeves. At low pressures, up to 500 atms., the sealing sleeve 18 has preferably a constriction 18a. At average pressure, between 500 and 1000 atms., the profile 18b is suitable, and the sleeve may be of uniform thickness or cross section, or approach such a shape.
For machines operating at very high pressure above 1000 atms. up to 1500 atms., the sealing sleeve 18 is formed with a thickened portion as shown in FIG. 6 and at 18c in FIG. 8. Due to the thicker part of the sleeve, the high pressure in the control chamber 22' near the low-pressure end cannot compress the sleeve 18 too much so that no metallic contact between the relatively movable surfaces of sleeve 18 and of piston means 15 can occur.
It is evident that the given ranges for shaping the profile of the sealing sleeve depending on the pressure on the high pressure end, may be varied, and depend on the dimentions of the sealing sleeve 18, including the dimensions of a bushing 19, on the elasticity and resilience of the material of the sleeve, and on the initial width of the gap 21.
Allowable Subject Matter
Claim 16 would be conditionally allowable if rewritten or amended to overcome the rejection(s) under 35 U.S.C. § 112(b).
Claim 5 would be conditionally allowable if rewritten to overcome the rejection under 35 U.S.C. § 112(b) and to include all of the limitations of the base claim and any intervening claims.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. The cited prior art discloses pumps and/or homogenizing devices.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CHARLES COOLEY whose telephone number is (571) 272-1139. The examiner can normally be reached M-F 9:30 AM - 6:00 PM.
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/CHARLES COOLEY/
Examiner, Art Unit 1774
DATED: 26 NOV 2025
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