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 Statement filed 6 JUNE 2023.
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 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).
Claim Rejections - 35 USC § 102
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 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). "A claim is anticipated only if each and every element as set forth in the claim is found, either expressly or inherently described, in a single prior art reference." Verdegaal Bros. Inc. v. Union Oil Co. of California, 814 F.2d 628, 631 (Fed. Cir. 1987).
The express, implicit, and inherent disclosures of a prior art reference may be relied upon in the rejection of claims under 35 U.S.C. 102 or 103. "The inherent teaching of a prior art reference, a question of fact, arises both in the context of anticipation and obviousness." In re Napier, 55 F.3d 610, 613, 34 USPQ2d 1782, 1784 (Fed. Cir. 1995) (affirmed a 35 U.S.C. 103 rejection based in part on inherent disclosure in one of the references). See also In re Grasselli, 713 F.2d 731, 739, 218 USPQ 769, 775 (Fed. Cir. 1983). See MPEP 2112.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless—
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1, 2, 3, 17, 18, and 19 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by WO 95/33608 that discloses the broadly recited screw element, namely an element 21 or 22 for a co-rotating twin screw processor 20, the element 21 or 22 having an axial bore (proximate 30) for mounting on a screw shaft 31 or 32 of the processor (each non-symmetrical modular mixing element 51, 52, 53 or 54 has an axial bore 56 for mounting on a shaft 30. The transport screw elements 45, 46 and 48 have bores and keyways (not shown) similar to those shown in Fig. 2 for the modular mixing elements) - page 14, lines 16-19 and Figure 2; the element comprising a continuous self-wiping flight 47, 49, or 60 helically formed thereon (page 21, second full paragraph), the element comprising a plurality of segments 45, 46, 48, 51-54, wherein the flight has a different lead in at least two segments of the plurality of segments:
Each round screw shaft 30 includes one or more keyways 40 (Fig. 2) extending longitudinally of the respective shaft parallel with the respective axis 31 or 32 for receiving keys 42 engaging in corresponding keyways 44 in the elements mounted on the shaft for providing a positive rotational drive connection between each round screw shaft 30 and the elements removably mounted thereon. In the region of the inlet opening 25 (Fig. 1) , each screw 21 and 22 includes a plurality of intermeshing co-rotating transport screw elements 45 and 46 mounted end-to-end on and keyed to their respective shafts. It is noted that the transport screw elements 46 are longer than screw elements 45, and the helical screw flights 49 of elements 46 have a proportionately longer lead than the helical screw flights 47 of elements 45 for rapidly transporting infed materials 27 downstream away from the inlet 25. Each of the transport screw elements 45 and 46 is shown having two helical screw flights 47 or 49, respectively. Each such flight extends around its respective screw axis 31 or 32 for one complete turn, i.e. 360°. (page 7, last paragraph).
The infed materials 27 include suitable plastic material and suitable additives to be compounded and mixed in the machine 20. Transport screw elements 45 and 46 in the respective screws 21 and 22 convey these materials to be processed to a first set 50-1 of modular mixing elements 51 and 52 mounted end-to-end on their respective shafts 30. Such a mixing set 50-1 as shown includes an RH-twist non-symmetrical modular mixing element 51 contiguous with and positioned immediately upstream from an LH-twist non- symmetrical modular mixing element 52. It is noted, as seen most clearly in Fig. 1A, that the two helical screw flights 47 of the transport screw element 45 which is positioned immediately upstream of the modular mixing element 51 are aligned with respective wing tips 60 (Figs. 2, 4A and 4B) of wings 62 (Figs. 2, 4A and 4B) of this mixing element 51. Thus, the two wing tips 60 of the mixing element 51 effectively form downstream continuations of the two helical screw flights 47, but the helix angle and lead of the wing tips 60 are different from the helix angle and lead of the screw flights 47. In other words, there is a sharp change (decrease) in helical twist at the junctures where the respective helical screw flights 47 are met by the respective wing tips 60 - page 8, second full paragraph.
Between the second mixing set 50-2 and the extruder outlet 38 is a final sequence of screw transport elements comprising in sequence: two screw elements 45, two longer screw elements 46 with flights 49 of lower helical pitch and longer lead located near the vent 36 and seven more screw elements 45. This final sequence of seven screw elements 45 serves for building pressure to expel the extrudate 39 through a die (not shown) at the outlet mouth 38. The longer screw elements 46 with their longer lead normally provide increased speed of downstream conveyance for preventing complete filling of the barrels near vent 36 for facilitating release of volatiles 37. It is noted that each shaft end 33 includes suitable fastening means for example such as a retainer nut, with a washer, threaded onto the shaft end for capturing and holding the string of assembled elements 45, 46, 51, 52, 45, 48, 53, 54, 45, 46 and 45 mounted on their respective shafts 30 for forming the screws 21 and 22. In each screw 21 and 22, the two flights 47 of the transport element 45 positioned immediately downstream from the modular mixing element 54 of the second mixing set 50-2, as seen more clearly in Fig. IB, are aligned with the tips 60 of wings 68 (Figs. 7A and 7B) of this mixing element effectively forming downstream continuations of the wing tips 60 of wings 68. There is a sharp reversal in helical twist at the juncture where each downstream-transporting screw flight 47 meets each upstream-pumping wing tip 60 of the modular mixing element 54 - page 9, last paragraph.
Figs. 7A and 7B show end elevational and side elevational views of non-symmetrical LH-twist modular mixing element 54 of 90° twist. This mixing element 54 is seen also in Figs. 1 and 1B. It has an axial length of two-thirds L and is similar to the mixing element 53, except that their helical twists are of equal pitch but opposite senses. Thus, mounted end-to-end in a set of 50-2 as shown in Fig. IB they form a cusp 106 which has a steeper V-shape than cusp 104 (Fig. 1A) since their axial lengths are shorter, thereby creating a larger helix angle (shorter lead) in their wing tips 60 than the helix angle for the wing tips 60 of the longer mixing elements 51 and 52 - page 21, first full paragraph.
wherein the flight has a different lead in two adjacent segments of the plurality of segments, such as the flights in segments 45 and 46, 48 and 53, 45 and 54, 45 and 51, and/or 45 and 52;
wherein the flight has a different lead in every segment of the plurality of segments, such as the flight in one each of the segments 45, 46, 48, 51, 52, 53;
wherein at least two segments 45, 46 may form a group of segments that repeats itself as a group along the length of the element 21 or 22 - Figures 1-1B;
wherein the group of segments 45 and 46 repeats itself along 30 to 90 percent of the length of the element 21 or 22 - Figure 1;
wherein each of the segments 45 or 46 is of equal length - Figures 1-1B.
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.
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).
Claims 1-19 are rejected under 35 U.S.C. 103 as being unpatentable over PADMANABAHN (US 2016/0279828 A1) in view of WO 95/33608.
PADMANABAHN ‘828 discloses the broadly recited screw element, namely an element for a co-rotating twin screw twin screw processor (abstract), the element having an axial bore for mounting on a screw shaft of the processor (Figs. 1a, 2a and 3), the element comprising a continuous self-wiping flight helically formed thereon (col. 1, lines 39-30 and lines 49-50), the element comprising a plurality of segments with a flight (Figs. 1a-3, col. 2, lines 31-34); and disclosing flights taking the form of an integer lobe flight, non-integer lobe flight, fractional lobe flight, a transition or transforming flight or combinations thereof as outlined below in the disclosure of PADMANABAHN ‘828:
An element for a co-rotating twin screw processor, the element having a lead ‘L’ and at least one continuous flight helically formed thereon and, wherein the flight transforms at least once from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead ‘L’ and transforms back to the first non-integer lobe flight in a fraction of the lead ‘L’ in the field of twin screw processors. More particularly, the disclosure relates to an element for a twin screw processor.
An element for a co-rotating twin screw processor is disclosed. The element has a lead ‘L’ and at least one continuous flight helically formed thereon and, wherein the flight transforms at least once from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead ‘L’ and transforms back to the first non-integer lobe flight in a fraction of the lead ‘L’.
In another aspect, an element for a co-rotating twin screw processor, the element having a lead ‘L’ and at least one continuous flight helically formed thereon and, wherein the flight transforms at least once from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead ‘L’ and transforms from the second non-integer lobe flight to a third non-integer lobe flight in a fraction of the lead is disclosed.
In another aspect, a twin screw processor is disclosed. The twin screw processor comprising a housing having at least two cylindrical housing bores, each housing bore having an axis disposed parallel to the other axis; at least a first screw shaft and a second screw shaft being disposed in the first and second housing bores; the first and second screw shaft being provided with elements defining a mixing zone; wherein at least one element has a lead ‘L’ and at least one continuous flight helically formed thereon and the flight transforms at least once from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead ‘L’ and transforms back to the first non-integer lobe flight in a fraction of the lead ‘L’.
FIG. 3 illustrates a co-rotating twin screw processor (100) comprising a housing (102) having two cylindrical housing bores (104A, 104B), each housing bore (104A, 104B) having an axis (108A and 108B respectively) disposed parallel to the other axis. A first screw shaft (106A) and a second screw shaft (106B) are disposed in the first and second housing bores (104A, 104B) respectively. Processing elements (10) or ‘elements’ are mounted on the first and second screw shafts (106A, 106B) and define a mixing zone within the processor (100). The elements (10) may comprise of a grooved axial bore in which splines of the screw shaft are engaged or other means for mounting on the screw shaft.
An element has one or more lobes that form a flight on the element. The number of lobes has conventionally been an integer and typically varies between one to three lobes. Such elements are referred to as “integer lobe element” in this disclosure. The number of lobes may also be a non-integer and such elements are referred to as “non-integer lobe element” or elements having a non-integer lobe flight.
A non-integer lobe element may be a fractional lobed element. A fractional lobed element is an element intermediate a first integer element (n) and a second integer element (N) by a predefined fraction, such that N/n is an integer and the fraction determines the degree of transition between the first integer and the second integer. A single flight lobe and a bi-lobe can form fractional lobes such as 1.2.xx, where xx can be any number from 1 to 99. The numbers 1 to 99 define whether the fractional lobe will look more like a single flight element or a bi-lobed element. The numbers 1 and 2 in the notation 1.2.xx represent the lobe element intermediate a single flight element (1) and a bi-lobe element respectively
An element (10) for a co-rotating twin screw processor (100) is disclosed. The element (10) has a lead and has at least one flight (12) helically formed thereon. The flight formed is continuous without any breaks or interruptions. The flight transforms at least once from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead and transforms back to the first non-integer lobe flight in a fraction of the lead ‘L’.
The first non-integer lobe flight may be a fractional lobe flight. The second non-integer lobe flight may be a fractional lobe flight. In other embodiments, the first non-integer lobe flight may be an irrational number lobe flight and the second non-integer lobe flight may an irrational number lobe flight. In other embodiments, both the first non-integer lobe flight and the second non-integer lobe flight may be fractional lobe flights. In other embodiments, both the first non-integer lobe flight and the second non-integer lobe flight may be irrational number lobe flights.
Referring to FIG. 1a, a front view of an element (10) in accordance with an embodiment of the present disclosure is illustrated. FIG. 1b shows the top view of the element (10) in FIG. 1a. The length of the element (10) may be equal to the lead of the element (10). In other embodiments, the length of the element (10) may be different than the lead ‘L’ of the element (10). The element (10) has a length of 200 mm and a lead ‘L’ also of 200 mm. At point A, the profile of the element (10) is a first fractional lobe element, i.e. 1.3.80 in the example illustrated. At point B, the profile of the element is a second fractional lobe element, i.e. 1.3.20. At point C, the profile of the element is again the first fractional lobe element, i.e. 1.3.80. The element (10) transforms from profile A to profile B to profile C. The transformation of the element (10) from profile A to profile B, takes place within a fraction of the lead ‘L’, 5 mm in the embodiment disclosed. The element (10) now transforms from profile B to profile C over the next 5 mm.
In the embodiment of FIG. 1b, the transformation from a first fractional lobe flight into second fractional lobe flight as well as the transformation from the second fractional lobe flight into the first fractional lobe flight takes place in 10 mm or within a fraction of the lead ‘L’.
In other embodiments, the flight transforms a plurality of times from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead ‘L’ and transforms back to the first non-integer lobe flight in a fraction of the lead ‘L.’ By way of example, the transformation from a first fractional lobe flight into second fractional lobe flight and back to first fractional lobe flight, or vice versa, may take place a plurality of times. In the embodiment of FIG. 1b transformation from a first fractional lobe flight into second fractional lobe flight and back to first fractional lobe flight is repeated twenty times along the length of the element (10) to obtain the 200 mm element.
In accordance with an embodiment, the first non-integer lobe flights for the plurality of transformations along the lead of the element (10) are the same. In other embodiments, the second non-integer lobe flights for the plurality of transformations along the lead of the element (10) are the same.
Referring now to FIG. 2a, a front view of an element (10) in accordance with another embodiment of the present disclosure is illustrated. FIG. 2b shows the top view of the element (10) of FIG. 2a. The element has a length of 150 mm and a lead also of 150 mm. At point A, the profile of the element is a first fractional lobe element, i.e. 1.3.80 in the example illustrated. At point B, the profile of the element is a second fractional lobe element, i.e. 1.3.20. At point C, the profile of the element is again the first fractional lobe element, i.e. 1.3.80. The element transforms from profile A to profile B to profile C. The transformation of the element from profile A to profile B, takes place within a fraction of the lead ‘L’, 5 mm in the embodiment disclosed. The element now transforms from profile B to profile C over the next 5 mm.
In the embodiment of FIG. 2b, the transformation from a first fractional lobe flight into second fractional lobe flight and back to first fractional lobe flight is repeated fifteen times along the length of the element (10) to obtain the 150 mm element.
The element (10) may have multiple continuous flights formed thereon. In an embodiment, each flight transforms at least once from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead ‘L’ and transforms back to the first non-integer lobe flight in a fraction of the lead ‘L’. The first non-integer lobe flights for each flight may be the same. The second non-integer lobe flights for each flight may be the same. The element (10) of FIG. 1a has several continuous helical flights formed thereon (12, 14 16).
In other embodiments, the flight transforms at least once from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead ‘L’ and transforms from the second non-integer lobe flight to a third non-integer lobe flight in a fraction of the lead ‘L’. By way of example, the flight transforms from a first fractional lobe flight to a second fractional lobe flight within a fraction of the lead ‘L’ and from the second fractional lobe flight to a third fractional lobe flight within a fraction of the lead L. The first non-integer lobe flight, the second non-integer lobe flight and the third non-integer lobe flight may be fractional lobe flights. In other embodiments, the first non-integer lobe flight, the second non-integer lobe flight and the third non-integer lobe flight may be irrational number lobe flights.
An element for a co-rotating twin screw processor, the element having a lead ‘L’ and at least one continuous flight helically formed thereon and, wherein the flight transforms at least once from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead ‘L’ and transforms back to the first non-integer lobe flight in a fraction of the lead ‘L’. Such element(s), wherein the first non-integer lobe flight is a fractional lobe flight. Such element(s), wherein the second non-integer lobe flight is a fractional lobe flight. Such element(s), wherein the first non-integer lobe flight is an irrational number lobe flight. Such element(s), wherein the second non-integer lobe flight is an irrational number lobe flight. Such element(s), having multiple continuous flights, each flight transforms at least once from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead ‘L’ and transforms back to the first non-integer lobe flight in a fraction of the lead ‘L’. Such element(s), wherein the first non-integer lobe flight for each flight is the same. Such element(s), wherein the second non-integer lobe flight for each flight is the same. Such element(s), wherein the flight transforms a plurality of times from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead ‘L’ and transforms back to the first non-integer lobe flight in a fraction of the lead ‘L’. Such element(s), wherein the first non-integer lobe flights for the plurality of transformations are the same. Such element(s), wherein the second non-integer lobe flights for the plurality of transformations are the same. Such element(s), wherein the length of the element is equal to the lead ‘L’.
An element for a co-rotating twin screw processor, the element having a lead ‘L’ and at least one continuous flight helically formed thereon and, wherein the flight transforms at least once from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead ‘L’ and transforms from the second non-integer lobe flight to a third non-integer lobe flight in a fraction of the lead ‘L’. Such element(s), wherein the first non-integer lobe flight, second non-integer lobe flight and the third non-integer lobe flight are fractional lobe flights. Such element(s), wherein the first non-integer lobe flight, second non-integer lobe flight and the third non-integer lobe flight are irrational number lobe flights.
A twin screw processor comprising a housing having at least two cylindrical housing bores, each housing bore having an axis disposed parallel to the other axis; at least a first screw shaft and a second screw shaft being disposed in the first and second housing bores; the first and second screw shaft being provided with elements defining a mixing zone; wherein at least one element has a lead ‘L’ and at least one continuous flight helically formed thereon and the flight transforms at least once from a first non-integer lobe flight into a second non-integer lobe flight in a fraction of the lead ‘L’ and transforms back to the first non-integer lobe flight in a fraction of the lead ‘L’. The length of the element can be equal to the lead ‘L.’
The element (10) as taught by the disclosure is an element suitable for use in co-rotating twin screw processors. The co-rotating twin screw processor may be a co-rotating twin screw extruder. The element is suitable for achieving a homogeneous melt mix and reducing material degradation by excessive shear. These elements prevent fatigue and thus prevent breakage in the elements or the shaft of the processor. The disclosed element (10) creates turbulence in the melt flow without stagnation. The disclosed element (10) does not provide any right angled face to the flow of material.
The disclosed element (10) provides for improved reliability, reduced wear and increased uniformity of melting and mixing. The element is effective in creating uniform shear, hence intensifying the shear effect. This enhances the melting efficiency and also the overall efficiency of the extruder to a great extent. It also prevents degradation of the material during melting.
PADMANABAHN ‘828 does not disclose the flight having a different lead in the segments. WO 95/33608 that discloses an element 21 or 22 for a co-rotating twin screw processor 20, the element 21 or 22 having an axial bore (proximate 30) for mounting on a screw shaft 31 or 32 of the processor (each non-symmetrical modular mixing element 51, 52, 53 or 54 has an axial bore 56 for mounting on a shaft 30. The transport screw elements 45, 46 and 48 have bores and keyways (not shown) similar to those shown in Fig. 2 for the modular mixing elements) - page 14, lines 16-19 and Figure 2; the element comprising a continuous self-wiping flight 47, 49, or 60 helically formed thereon (page 21, second full paragraph), the element comprising a plurality of segments 45, 46, 48, 51-54, wherein the flight has a different lead in at least two segments of the plurality of segments as outlined above; wherein the flight has a different lead in two adjacent segments of the plurality of segments, such as the flights in segments 45 and 46, 48 and 53, 45 and 54, 45 and 51, and/or 45 and 52; wherein the flight has a different lead in every segment of the plurality of segments, such as the flight in one each of the segments 45, 46, 48, 51, 52, 53; wherein at least two segments 45, 46 may form a group of segments that repeats itself as a group along the length of the element 21 or 22 - Figures 1-1B; wherein the group of segments 45 and 46 repeats itself along 30 to 90 percent of the length of the element 21 or 22 - Figure 1; and wherein each of the segments 45 or 46 is of equal length - Figures 1-1B.
It would have been obvious to one skilled in the art before the effective filing date of the invention to have provided PADMANABAHN ‘828 with the flight having a different lead in the segments for the purposes of rapidly transporting infed materials downstream away from the inlet, for building pressure to expel the extrudate through a die at the outlet of the processor, and to provide increased speed of downstream conveyance for preventing complete filling of the barrels near a vent for facilitating release of volatiles from the vent - per page 7, last paragraph and page 9, last paragraph of WO 95/33608.
Claims 1-19 are rejected under 35 U.S.C. 103 as being unpatentable over PADMANABAHN (US 2014/0036614 A1) in view of WO 95/33608.
PADMANABAHN ‘614 discloses the broadly recited screw element, namely an element for a co-rotating twin screw processor (abstract), the element having an axial bore for mounting on a screw shaft of the processor (Figs. 2 and 3), the element comprising a continuous self-wiping flight helically formed thereon ([0047), the element comprising a plurality of segments with a flight ([0021] -[0023]); and disclosing flights taking the form of an integer lobe flight, non-integer lobe flight, fractional lobe flight, a transition or transforming flight or combinations thereof as outlined below in the disclosure of PADMANABAHN ‘614:
A dispersive mixing element for co-rotating twin screw extruder is disclosed. The element for co-rotating twin screw extruder comprises of a continuous flight helically formed thereon having a lead `L`, wherein either the flight transforms at least once from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforms back to an integer lobe flight in a fraction of the lead `L` or the flight transforms at least once from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L` and transforms back to a non-integer lobe flight in a fraction of the lead `L`. The invention relates to a screw element for extruders. Specifically, the invention relates to a mixing element for co-rotating twin screw extruders.
Co-rotating twin screw extruders are widely used not only for production, compounding and processing of plastics but also in other industries such as rubber, food, paint and pharmaceutical processing. Co-rotating extruders are built today in a modular manner with different processing elements mounted on screw shafts that allow the extruder to be adapted to different processing requirements. As opposed to single screw machines where the screw flight scrapes the inside of the housing (with clearance), an essential aspect of closely intermeshing co-rotating extruders is that the flights mesh tightly, except for the necessary clearance, and the screws are considered as "self-wiping" or "self-cleaning" with the flights designed to clean each other. The evolution, principles of operation and design principles of co-rotating twin screw extruders are well known. The invention is an extruder element for co-rotating extruders that eliminates or reduces the peak shear experienced by material, increases distributive mixing for more homogeneous mixing and better melt temperature control and also maintains the self-wiping ability of the extruder.
An element for co-rotating twin screw extruder is disclosed. The element for co-rotating twin screw extruder comprises of a continuous flight helically formed thereon having a lead `L`, wherein either the flight transforms at least once from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforms back to an integer lobe flight in a fraction of the lead `L` or the flight transforms at least once from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L` and transforms back to a non-integer lobe flight in a fraction of the lead `L`.
A co-rotating extruder comprises a housing having two cylindrical housing bores, each housing bore having an axis disposed parallel to the other axis. A first screw shaft and a second screw shaft are disposed in the first and second housing bores respectively. Extruder processing elements are mounted on the first and second screw shaft and define a mixing zone within the extruder. The extruder element may comprise of a grooved axial bore in which splines of the screw shaft are engaged or other means for mounting on the screw shaft.
An extruder element has one or more lobes that form a flight on the element. The number of lobes has conventionally been an integer and typically varies between one to three lobes. Such extruder elements are referred to as "integer lobe element" in this disclosure. The number of lobes may also be a non-integer and such elements are referred to as "non-integer lobe element" or transitional lobe element.
An element for a co-rotating twin screw extruder is disclosed. The element has a lead `L` and has a flight helically formed thereon. The flight formed is continuous without any breaks or interruptions. The flight transforms at least once from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforms back to an integer lobe flight in a fraction of the lead `L` or the flight transforms at least once from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L,` and transforms back to a non-integer lobe flight in a fraction of the lead `L` . This transformation of the element profile forms at least one pin or one groove or both on the element such that on assembly of a pair of elements, the pin profile of one element engages the groove profile on the other element.
Referring to FIG. 1 (a), a pair of co-rotating extruder elements in accordance with an embodiment of the invention, in assembly, is illustrated. Each element has a length of 40 mm and a lead `L` also of 40 mm. At point A, the profile of the element is an integer lobe element, bi lobe in the example illustrated. The profile of the element at point A is illustrated in FIG. 1 (b) as profile 1. Profiles 2 to 40 are non-integer lobe profiles. The element transforms from profile 1 to profile 2 and so on successively till profile 40. The transformation of the element from profile 1, an integer lobe element profile, to profile 40, a non-integer lobe element profile, takes place within a fraction of the lead `L`, 5 mm in the embodiment disclosed. The element now transforms back from profile 40 to profile 1 over the next 5 mm. The transformation of the element from profile 40 to profile 1 results in the non-integer lobe element profile to transform into an integer lobe element profile within a fraction of the lead `L`. In the embodiment of FIG. 1, profile 1 is a bi-lobe element while profile 40 is a 1:2:50 fractional lobe element.
In the embodiment of FIG. 1, the transformation from an integer lobe flight into a non-integer lobe flight as well as the transformation from a non-integer lobe flight into an integer lobe flight takes place in 10 mm or within a fraction of the lead `L`.
Furthermore, in accordance with an embodiment the transformation from an integer lobe flight into a non-integer lobe flight and back or vice versa may take place a plurality of times. In the embodiment of FIG. 1, the transformation from an integer lobe flight into a non-integer lobe flight and back is repeated four times along the length of the element to obtain the 40 mm element.
While the embodiment of FIG. 1 illustrates a transformation from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and back in a fraction of the lead `L,`, the element can equally transform from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L` and back to a non-integer lobe flight in a fraction of the lead `L`.
In accordance with an embodiment, the element has multiple flights and a lead `L`. At least one flight either transforms from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforms back to a integer lobe flight in a fraction of the lead `L` or the flight transforms at least once from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L` and transforms back to a non-integer lobe flight in a fraction of the lead `L`. In accordance with an alternate embodiment, the element has multiple flights and a lead `L` with each flight either transforms from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforms back to a integer lobe flight in a fraction of the lead `L` or the flight transforms at least once from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L` and transforms back to a non-integer lobe flight in a fraction of the lead `L`.
A non-integer lobe element may be a fractional lobed element. A fractional lobed element is an element intermediate a first integer element (n) and a second integer element (N) by a predefined fraction, such that N/n is an integer and the fraction determines the degree of transition between the first integer and the second integer. A single flight lobe and a bi-lobe can form fractional lobes such as 1.2.xx, where xx an be any number from 1 to 99. The numbers 1 to 99 define whether the fractional lobe will look more like a single flight element or a bi-lobed element. The numbers 1 and 2 in the notation 1.2.xx represent the lobe element intermediate a single flight element (1) and a bi-lobe element respectively (2). Examples of a fractional lobe element formed from a single lobe and a bi-lobe element are illustrated in FIG. 1 and more completely described in U.S. Pat. No. 6,783,270.
A single flight element and a four lobe element can also form a fractional element designated by 1.4.xx, where xx could be any number from 1 to 99. Thus a fractional lobe element represented as 1.4.50 represents an element mid-way between a single flight and a four lobe element. Similarly, a single lobe element and a tri-lobe element [1.3.xx] or a bi-lobe and a four lobe element [2.4.xx] may also be combined. These combinations result in a large number of fractional lobe elements.
A non-integer lobe element may be an irrational number lobed element. Irrational number lobed elements are known. The element as taught by this disclosure may therefore transform from a regular or integer lobe flight to a fractional lobe flight in a fraction of the lead "L` and back or may transform from a from a regular or integer lobe flight to an irrational number lobe flight in a fraction of the lead "L` and back.
Referring to FIGS. 2 to 9, different views of an element (100) in accordance with an embodiment of the invention are illustrated. FIGS. 2 and 3 illustrate solid isometric views of the element (100) having a central bore (101) with splines formed thereon for mounting the element on a screw shaft of an extruder. The central bore extends along element axis X1-X2. While FIG. 2 views the element from the end X2 of the element axis, FIG. 3 views the element from the end X1 of the element axis. The element transforms from an integer lobe element into a non-integer lobe element, fractional lobe element with the fraction 1:2:50, and back to an integer lobe element four times along the axis X1-X2. Pins (102) and grooves are (103) are formed on the element.
FIG. 4 illustrates an isometric line drawing of the element of FIGS. 2 and 3 along element axis X1-X2. FIG. 5 illustrates the left side view or the view from side A of the cross sectional axis A-B of FIG. 4 while FIG. 6 illustrates the right side view or the view from side B of the cross sectional axis A-B of FIG. 4.
FIG. 7 illustrates the element as seen from side B of the cross sectional axis A-B of FIG. 4 by rotating the element anti-clockwise along axis X1-X2. FIG. 8 also illustrates the element as seen from side B of the cross sectional axis A-B of FIG. 4 by rotating the element anti-clockwise along axis X1-X2, and as seen from end X2 of the elemental axis X1-X2. FIG. 9 is the solid elemental view of the element of FIG. 8.
FIGS. 10 and 11 illustrate the front and back views of the element of FIG. 4. As seen from the front and back view the element is a two lobe element at the ends and transforms into a non-integer element and back along the elemental axis X1-X2.
An element for co-rotating twin screw extruder is disclosed. The element for co-rotating twin screw extruder comprises of a continuous flight helically formed thereon having a lead `L`, wherein either the flight transforms at least once from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforms back to an integer lobe flight in a fraction of the lead `L` or the flight transforms at least once from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L` and transforms back to a non-integer lobe flight in a fraction of the lead `L`. Such element(s) for co-rotating twin screw extruder wherein the non-integer lobe flight is a fractional lobe flight. Such element(s) for co-rotating twin screw extruder wherein the non-integer lobe flight is an irrational number lobe flight. Such element(s) for co-rotating twin screw extruder wherein the transformation of the flight from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforming back to an integer lobe flight in a fraction of the lead `L` or the transformation of the flight from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L` and transforming back to a non-integer lobe flight in a fraction of the lead `L` forms a pin and groove on the element. Such element(s) for co-rotating twin screw extruder wherein the element has multiple flights and a lead `L` with at least one flight either transforms from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforms back to a integer lobe flight in a fraction of the lead `L` or the flight transforms at least once from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L` and transforms back to a non-integer lobe flight in a fraction of the lead `L`. Such element(s) for co-rotating twin screw extruder wherein the element has multiple flights and a lead `L` with each flight either transforms from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforms back to a integer lobe flight in a fraction of the lead `L` or the flight transforms at least once from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L` and transforms back to a non-integer lobe flight in a fraction of the lead `L`. Such element(s) for co-rotating twin screw extruder wherein the flight transforms a plurality of times from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforms back to an integer lobed flight in a fraction of the lead `L`.Such element(s) for co-rotating twin screw extruder wherein the flight transforms from an integer lobe flight into a non-integer lobe flight and transforms back to a integer lobe flight in a fraction of the lead `L`.
The element as taught by the disclosure is a mixing element suitable for use in co-rotating twin screw extruders. The element is suitable for achieving a homogeneous melt mix and reducing material degradation by excessive shear. The element as taught also does not compromise on the self-wiping ability of the co-rotating extruder.
Theinvention thus discloses an element for a co-rotating twin screw extruder comprising a continuous flight helically formed thereon having a lead `L`, wherein either the flight transforms at least once from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforms back to an integer lobe flight in a fraction of the lead `L` or the flight transforms at least once from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L` and transforms back to a non-integer lobe flight in a fraction of the lead `L`; wherein the non-integer lobe flight is a fractional lobe flight; wherein the non-integer lobe flight is an irrational number lobe flight; wherein the transformation of the flight from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforming back to an integer lobe flight in a fraction of the lead `L` or the transformation of the flight from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L` and transforming back to a non-integer lobe flight in a fraction of the lead `L` forms a pin and groove on the element; wherein the element has multiple flights and a lead `L` with at least one flight either transforms from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforms back to a integer lobe flight in a fraction of the lead `L` or the flight transforms at least once from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L` and transforms back to a non-integer lobe flight in a fraction of the lead `L`; wherein the element has multiple flights and a lead `L` with each flight either transforms from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforms back to a integer lobe flight in a fraction of the lead `L` or the flight transforms at least once from a non-integer lobe flight into an integer lobe flight in a fraction of the lead `L` and transforms back to a non-integer lobe flight in a fraction of the lead `L`; wherein the flight transforms a plurality of times from an integer lobe flight into a non-integer lobe flight in a fraction of the lead `L` and transforms back to an integer lobed flight in a fraction of the lead `L`; and wherein the flight transforms from an integer lobe flight into a non-integer lobe flight and transforms back to a integer lobe flight in a fraction of the lead `L`.
PADMANABAHN ‘614 does not disclose the flight having a different lead in the segments. WO 95/33608 that discloses an element 21 or 22 for a co-rotating twin screw processor 20, the element 21 or 22 having an axial bore (proximate 30) for mounting on a screw shaft 31 or 32 of the processor (each non-symmetrical modular mixing element 51, 52, 53 or 54 has an axial bore 56 for mounting on a shaft 30. The transport screw elements 45, 46 and 48 have bores and keyways (not shown) similar to those shown in Fig. 2 for the modular mixing elements) - page 14, lines 16-19 and Figure 2; the element comprising a continuous self-wiping flight 47, 49, or 60 helically formed thereon (page 21, second full paragraph), the element comprising a plurality of segments 45, 46, 48, 51-54, wherein the flight has a different lead in at least two segments of the plurality of segments as outlined above; wherein the flight has a different lead in two adjacent segments of the plurality of segments, such as the flights in segments 45 and 46, 48 and 53, 45 and 54, 45 and 51, and/or 45 and 52; wherein the flight has a different lead in every segment of the plurality of segments, such as the flight in one each of the segments 45, 46, 48, 51, 52, 53; wherein at least two segments 45, 46 may form a group of segments that repeats itself as a group along the length of the element 21 or 22 - Figures 1-1B; wherein the group of segments 45 and 46 repeats itself along 30 to 90 percent of the length of the element 21 or 22 - Figure 1; and wherein each of the segments 45 or 46 is of equal length - Figures 1-1B.
It would have been obvious to one skilled in the art before the effective filing date of the invention to have provided PADMANABAHN ‘614 with the flight having a different lead in the segments for the purposes of rapidly transporting infed materials downstream away from the inlet, for building pressure to expel the extrudate through a die at the outlet of the processor, and to provide increased speed of downstream conveyance for preventing complete filling of the barrels near a vent for facilitating release of volatiles from the vent - per page 7, last paragraph and page 9, last paragraph of WO 95/33608.
Allowable Subject Matter
No claims stand allowed.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. The cited prior art discloses elements for screws used in extruders.
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/CHARLES COOLEY/
Examiner, Art Unit 1774
DATED: 2 MARCH 2026