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)).
Drawings
The drawings are objected to under 37 CFR § 1.84 in view of the following deficiencies that require correction:
The reference characters and lines forming the Figures 1-10 are of poor quality (not uniformly thick and well-defined - 37 CFR 1.84(l): 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.
Figure 1 should be designated by a legend such as --Prior Art-- because only that which is old is illustrated. See MPEP § 608.02(g).
The drawings contain improper sectional/directional 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 4 should be a sectional view taken along line 4-4 in Figure 2 (not nearly illegible sectional line A-A). All sectional views should be corrected in accordance with 37 CFR 1.84(h)(3).
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.
Applicant should thus verify that (1) all reference characters in the drawings are described in the detailed description portion of the specification and (2) all reference characters mentioned in the specification are included in the appropriate drawing Figure(s) as required by 37 CFR 1.84(p)(5).
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 abstract is acceptable.
The title is acceptable.
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 1-10 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.
Claim 1, line 4: ”the inner cylinder” lacks antecedent basis; in line 5: are the “auxiliary blades” related to the auxiliary blades recited in line 1?; in line 7: “the screw passage space” lacks antecedent basis.
Claim 2: “the root of the auxiliary blade”, “the outer peripheral surface of the inner cylinder”, and “the screw blade” all lack antecedent basis. Note “the screw blade” in claim 2 does not correspond to “screw blades” recited in claim 1.
Claim 5: “the curved surface of the curved surface” is redundant and lacks antecedent basis; “the rotary drum” lacks antecedent basis.
Claim 6: “the included angle α” and “the included angle β” lack antecedent basis.
Claim 7: “the discharge hole” lacks antecedent basis.
Claim 8: “the adjacent two blades” and “the sde welding positions” lack antecedent basis.
Claim 9: “the solid phase end” and “the liquid phase end”.
Claim 10: “the outer cylinder” lacks antecedent basis.
The use of a confusing variety of terms for the same thing should not be permitted - MPEP 608.01(o). Such as “”hollow internal cylinder” vs. “inner cylinder”, etc.
Also see 37 CFR 1.121(e) Disclosure consistency. The disclosure must be amended, when required by the Office, to correct inaccuracies of description and definition, and to secure substantial correspondence between the claims, the remainder of the specification, and the drawings.
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, 4, 6, 7, 8, and 10 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by KR 10-1490746 that shows in Figures 2-5b a screw conveyor 20 having auxiliary blades 30, a hollow internal cylinder 20 is provided with a tapered section and a straight section (Figure 5a); a feed hole 24 is arranged on the tube wall near the tapered section, and screw blades 23 are arranged on the outer periphery of the inner cylinder 20; a plurality of the auxiliary blades 30 are arranged between the screw blades 23, the width of the auxiliary blades 30 is smaller than the pitch of the screw blades 23, and two adjacent auxiliary blades 30 are alternately arranged in the screw passage space to form a zigzag flow passage (Figures 2-5b);
the root of the auxiliary blade 30 is welded to the outer peripheral surface of the inner cylinder 20, one side is welded to the screw blade 23 on one side of the screw passage, and the other side is a certain distance from the screw blade 23 on the other side of the screw passage (Figures 2-5b and per the machine translation reproduced below);
said distance t is 20% to 80% of the screw pitch (Figures 2-5b);
the auxiliary blades 30 are planar straight blades or curved blades (Figures 2-5b);
the included angle between the auxiliary blades 30 and the central axis of the rotary drum 10 is 0 to 45 degrees or the included angle between the auxiliary blade 30 and the diameter of the rotary drum 10 is 0 to 90 degrees;
the auxiliary blade 30 is arranged in a screw passage behind the discharge hole 24 (Figures 2-5b);
the auxiliary blades 30 are evenly distributed within each screw pitch, the adjacent two blades 30 are arranged in parallel or staggered, and the side welding positions of the two auxiliary blades 30 on both sides of the screw blades 23 are staggered (Figures 2-5b);
a screw conveyor 20 having auxiliary blades 30 is arranged in the outer cylinder/drum 10.
More specifically, KR 10-1490746 (from said machine translation) discloses a centrifugal dehydrator having the improved dehydration performance, which comprises outer cylinder including a slope part having the diameter become wider from the front end where the sludge flows in, and a cylinder part having a cylindrical shape; an inner screw including multiple screw blades formed inside the outer cylinder, consisting of a cone formed on a straight part and a slope part, and formed between the outer cylinder, an outlet formed between the straight part and cone and have a deposited sludge be discharged, and multiple guide vanes formed on the screw blades of the cone; a separation solution outlet formed on the back end between the outer cylinder and the inner screw and having a separation solution be discharged; and a cake disperser formed on the front end between the outer cylinder and the screw and having a deposited solid be discharged. According to the present invention, the effect of improving the dehydration performance by causing the discharge of gap solution in a solid is obtained by adding the crushing function to make the discharge of the solution in the solid be smooth by the guide vanes.
The present invention relates to a centrifugal dehydrator, and more particularly, to a centrifugal dehydrator having a plurality of guide vanes in a screw vane to improve dehydration performance.
Generally, in the process of treating various wastes in treatment facilities such as sedimentation basin, sludge is formed by aggregating suspended solids in wastewater by adding an inorganic control agent such as ash, iron chloride or a polymerization coagulant to the sludge, However, in recent years, in the case of sludge treatment by landfill, various kinds of contamination are generated, and therefore, an incineration treatment method is mainly used.
In this incineration treatment method, since the sludge collected from the ordinary treatment facilities is at least 90% of the weight of the sludge, water is required to be dewatered using the dewatering device for incineration treatment. If the sludge having less dewatering is incinerated, A large amount of heat energy is required for evaporation, and since the combustion efficiency is lowered and pollutants are generated, dehydration is desirably carried out as appropriate for incineration as possible.
As a device for dewatering such sludge, a centrifugal dehydrator having an excellent water content is mainly used. As a conventional centrifugal dehydrator, a "centrifugal dehydrator" (Registration Practical Utility Model No. 20-0407420) is disclosed. 1 shows a centrifugal dehydrator according to the prior art. As shown in Fig. 1, this conventional technique includes a cylinder 10 formed of a cylindrical portion and a conical portion, a supply pipe 16 for supplying sludge in the cylinder, a screw 11 for transferring sludge around the cylinder, A bowl 12 having a water outlet 17 for discharging water to one side of the screw around the screw and a sludge outlet 18 at the other side of the bowl. Here, reference numerals related to FIG. 1 are for explanation of a centrifugal dehydrator according to the prior art, and are not related to the reference numerals according to the present invention described below.
In the cylindrical part of the cylinder, the liquid and solids due to the difference in density are separated mainly from the dehydration function, and the separated sludge is mainly subjected to the centrifugal force, so that complete dehydration is not achieved. Thereafter, the sludge is conveyed to the conical portion by riding on the front wall surface of the screw blade. The sludge is stagnated due to the centrifugal force and the slipping phenomenon of the additional sludge.
On the other hand, such a centrifugal dehydrator has changed the screw shape of the cone portion, that is, the cone portion, as a technique for improving the dewatering performance. For example, a technique of reducing the pitch of the screw blade to the cylindrical portion, that is, the straight portion, or lengthening the dewatering region by lengthening the cone portion relatively is used. However, in this method, a certain amount of accumulated sludge is required to produce a compaction force, and there is a limit to the effect of increasing the water content in terms of function, and when the concentration of the inflow sludge is low, the effect is extremely poor, have.
Hereinafter, a centrifugal dehydrator with improved dehydration performance according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 2 is a cross-sectional view of a centrifugal dehydrator with improved dewatering performance according to the present invention, and FIG. 3 is an enlarged sectional view of an outer cylinder and an inner screw of the centrifugal dehydrator with improved dewatering performance according to the present invention. 4A to 4C are enlarged views of a cone and a guide vane of an inner screw of a centrifugal dehydrator with improved dewatering performance according to the present invention. FIGS. 5A and 5B are views showing the inner and outer surfaces of a centrifugal dehydrator FIG. 5 is an enlarged perspective view of a cone and guide vanes of a screw.
FIG. 2 to 5 show a centrifugal dehydrator 100 having improved dewatering performance according to the present invention includes an outer cylinder 10, an inner screw 20, a desorbing liquid outlet 40, and a cake outlet 50. The outer cylinder (10) is constituted by an inclined portion (11) and a cylindrical portion (12). The inclined portion 11 gradually increases in diameter from the front end into which the sludge flows, and the cylindrical portion 12 is a cylindrical portion. A feed pipe (13) is fixed to the front end of the outer cylinder (10), and the sludge is introduced through the feed pipe (13). The inner screw (20) is provided inside the outer cylinder (10). The inner screw 20 is composed of a cone 21 provided in a portion of the inclined portion 11 of the outer cylinder 10 and a straight portion 22 provided in the cylindrical portion 12. In the straight portion 22, separation of liquid and solids due to density difference is performed rather than dehydration function. Here, the separated sludge is mainly subjected to centrifugal force, and complete dehydration is not achieved. Thereafter, the front wall surface of the screw blade 23 is conveyed to the cone 21, and the conveyed sludge solid is subjected to a stagnation phenomenon due to the centrifugal force and the slipping phenomenon of the additional sludge. As a result, . Here, in addition to dewatering due to the compression effect by the above-mentioned consolidation force, the present invention adds the function of the crushing effect by the guide vane 30 to smooth liquid discharge between the solids.
The inner screw 20 includes a screw vane 23, an outlet 24, and a guide vane 30. The screw vane 23 is formed between the inner screw 20 and the outer cylinder 10 and rotates, and a plurality of screw vanes 23 are provided. The screw blade 23 is thermally sprayed or tiled to prevent wear and is formed integrally with the inner screw 20.
The discharge port 24 is formed at a portion between the cone 21 and the straight portion 22 of the inner screw 20 to discharge the settled sludge. That is, the sludge passes through the cone 21 of the inner screw 20, and a vortex is generated, so that the particles of a large size or density contained in the raw material, that is, the settled sludge, are collected by the centrifugal force while being rotated by the centrifugal force. This settled sludge is discharged through the outlet 24. Most of the liquid in the sludge collects in the central portion of the cone 21 accompanied by particles of a small size or density depending on the conditions to form a swirling vortex and flows into the straight portion 22.
The guide vane 30 is formed in the screw blade 23 of the cone 21 of the inner screw 20, and a plurality of guide vanes 30 are provided. The shape of the guide vane 30 is shown in detail in Figs. 4A to 4C, 5A and 5B. The guide vane 30 is inclined at an angle of, for example, 30 to 60 degrees as shown in FIG. 4B. The guide vane 30 is provided to have a height B of 2/3 of the height of the screw vane 23, as shown in Fig. 5B. The guide vane 30 is provided to have a length C of 1/2 of the pitch P of the screw blades 23 as shown in Figs. 4A and 5B. The sludge is crushed by the guide vane 30 and the squeezing effect of the sludge on the guide vane 30 between the outer one end of the guide vane 30 and the inner wall of the outer cylinder 10 is suitably adjusted And the sludge can be prevented from becoming stagnant.
As shown in FIG. 4A, the guide vane 30 is provided so that the interval between the outer one end and the inner wall of the outer cylinder 10 is 5 to 10 mm. A space may be formed through which the remaining sludge other than the amount of sludge on the guide vane 30 is smoothly moved along the lower screw vane 23. As shown in FIG. 4B, a plurality of guide vanes 30 are provided at predetermined intervals so as to be inclined in the rightward direction, or a plurality of guide vanes 30 are provided at predetermined intervals so as to be inclined in the leftward direction, as shown in FIG. 4C. The guide vane 30 is sprayed or tiled to prevent wear and is formed integrally with the inner screw 20 through bolts or welding.
The desorption liquid outlet (40) is formed at the rear end between the outer cylinder (10) and the inner screw (20), and the desorption liquid is discharged. The introduced sludge is separated into solid and liquid by the difference in density through the above-described structures, and the desorbing liquid, which is a relatively light liquid, is discharged through the inner screw vane 34 to the desorbing liquid outlet 40 having a low pressure.
The cake outlet 50 is formed at the front end between the outer cylinder 10 and the inner screw 20 to discharge the precipitated solid matter. The cake, which is a solid component separated by the difference in density, is discharged through the screw blade (23) to the cake discharge opening (50). In order to smoothly discharge the cake, the cake is formed so as to be inclined from the discharge port (24) to the cake discharge port (50).
KR ‘746 thus discloses an outer cylinder made up of an inclined portion having an inner diameter gradually widened from a front end to which sludge flows and a cylindrical portion having a cylindrical shape; a plurality of screw vanes provided in the outer cylinder and composed of a straight portion provided in the cylindrical portion and a cone provided in the inclined portion and rotated and formed between the outer cylinder passes, An outlet for discharging sedimented sludge formed in the cone portion, and an outlet for discharging the sedimented sludge at an angle of 30 to 60 degrees to the screw blade of the cone, a height of 2/3 of the height of the screw blade and a length of 1/2 of the pitch of the screw blade An inner screw having a guide vane having a gap of 5 to 10 mm between the outer end and the inner wall of the outer cylinder and having a plurality of guide vanes inclined rightward or leftward; a desorption liquid outlet formed at the rear end between the outer cylinder and the inner screw to discharge the desorption liquid; and a cake discharging opening formed at a front end between the outer cylinder and the inner screw to discharge the precipitated solid matter.
Claims 1, 4, 5, 6, 7, 8, 9, and 10 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by HRUSCHKA et al. (US 6908423 B2) that shows in Figures 1-3 a screw conveyor 3 having auxiliary blades 29, a hollow internal cylinder is provided with a tapered section 11 and a straight section 9 (Figures 1 and 3); a feed hole 17 is arranged on the tube wall near the tapered section, and screw blades 5 are arranged on the outer periphery of the inner cylinder; a plurality of the auxiliary blades 29 are arranged between the screw blades 5, the width of the auxiliary blades 29 is smaller than the pitch of the screw blades 5, and two adjacent auxiliary blades 29 are alternately arranged in the screw passage space to form a zigzag flow passage (Figures 1-3);
the auxiliary blades 29 are planar straight blades or curved blades (Figures 1-3);
the curved surface of the curved surface of the auxiliary blades 29 is convex in a direction consistent with the rotational direction of the rotary drum 21 (Figures 1-3);
the included angle between the auxiliary blades 29 and the central axis of the rotary drum 21 is 0 to 45 degrees or the included angle between the auxiliary blade 29 and the diameter of the rotary drum 21 is 0 to 90 degrees;
the auxiliary blade 29 is arranged in a screw passage behind the discharge hole 17 (Figure 3);
the auxiliary blades 29 are evenly distributed within each screw pitch, the adjacent two blades 29 are arranged in parallel or staggered, and the side welding positions of the two auxiliary blades 29 on both sides of the screw blades 5 are staggered (Figures 1-3);
the height of the auxiliary blades 29 is not higher than the height of the screw blades 5, and the height is equal or the height increases sequentially from the solid phase end to the liquid phase end (Figure 2b);
and a screw conveyor 3 having auxiliary blades 29 is arranged in the outer cylinder/drum 21.
More specifically, HRUSCHKA et al. discloses a screw for a solid-bowl screw-type centrifuge, comprising: a screw body having a circumference, a cylindrical section and a conical section; at least one screw blade surrounding the screw body several times and forming several screw spirals; a delivery path for conveying material to be centrifuged formed between the screw spirals; blade segments arranged in the delivery path between adjacent screw spirals only in a portion of the cylindrical section; and recesses in the at least one screw blade, the recesses constructed only in a portion of the cylindrical section and constructed such that the material to be centrifuged can flow through between adjacent screw spirals. A method for extracting oil in a two- and three-phase separation process using the screw of the present invention.
The invention relates to a screw for a solid-bowl screw-type centrifuge and to a method of extracting oil by means of a solid-bowl screw-type centrifuge via a screw or kneading screw for a solid-bowl screw-type centrifuge which has at least one screw blade and at least one screw blade segment in a delivery path in sections or areas between adjacent screw spirals. In addition, the at least one screw blade is preferably provided with recesses which are constructed such that centrifuged material can flow through between adjacent screw spirals.
With respect to the method of separating or extracting oil, it was found to be particularly favorable for the oil, as a liquid phase, to be extracted directly in a two-phase separating process. The oil is extracted as a liquid or first phase from a second or mixed phase which may include a mixture of water and solids. Thus, seeds or reduced fruit, such as olives or avocados, are first guided into a solid-bowl screw-type centrifuge through a first portion of a separating zone having at least one screw blade with one or more screw spirals in a cylindrical section of the centrifuge. The at least one screw blade is preferably constructed without any recesses in a delivery path area between the screw spirals and, preferably, no blade segments are constructed in the delivery path. Subsequently, a passing takes place into a second portion of the separating zone in which recesses are constructed in the at least one screw blade, and blade segments are constructed the delivery path. Then the solids and the water are conveyed past a retarding plate or disk, which acts as a barrier to the oil, from the separating zone into a conically tapering section or dry zone of the screw and then out of the centrifuge. The oil is conveyed in an opposite direction out of the centrifuge.
Also, by use of the screw according to the present invention, a three-phase oil extraction process, which is still occasionally used, can be improved. In this case, oil is separated or extracted as a liquid or first phase, in a three-phase separating process, from a second phase comprising water and a third phase comprising solids. The process occurs as follows: the reduced fruit, such as olives or avocados or seeds are first guided into a solid-bowl screw-type centrifuge through a first portion of a separating zone having at least one screw blade with one or more screw spirals in a cylindrical section of the centrifuge. The at least one screw blade is preferably constructed without recesses, and preferably with no blade segments constructed in the delivery path between the screw spirals, then, a passing takes place into a second portion of the separating zone, in which recesses are constructed in the at least one screw blade and blade segments are constructed in the delivery path, then the three phases, water, solids and oil are guided/delivered out of the centrifuge essentially separately. The water and oil may exit at different levels toward a cylindrical end of the centrifuge and the solids may exit toward a conical end of the centrifuge.
By use of the screw according to the present invention, the economic efficiency of the oil extraction can be increased considerably. In this regard, reference is particularly made to tests explained herein and whose results are shown in FIGS. 4 and 5. The screw of the present invention can also be retrofitted without any problem into existing centrifuges. The screw according to the present invention is particularly suitable for an application in a process for extracting oil from fruit and seeds and for a better draining of water and/or separating of oil from mashes of organic materials (such as seed mash, fruit flesh mash, animal tissue, such as fish, egg, fatty tissue cells).
A combination of recesses and blade segments are provided. The blade segments and the recesses preferably are constructed such in the axial direction that the recesses each form ducts extending in the axial direction (and/or at an angle or in a zigzag-type manner with respect to the center axis y), in which ducts the blade segments stand.
Also according to the present invention, the blade segments and the recesses may be constructed only in the cylindrical section of the screw body and a retarding disk may be provided in the conical section of the screw, particularly in the two-phase separation.
The blade segments in the delivery path may be constructed such that they extend into an area where solids are present, such as a solids area. However, there is an exterior area of, for example, approximately 25 mm that is preferably not reached by the blade segments, because relatively completely de-oiled solids and permanently discharged solids are already present in this exterior area.
Measuring results indicate that the screw according to the present invention leaves approximately 1 to 1.5% less oil in a discharged solids sludge. During an olive oil extraction campaign, this corresponds to a financial savings of approximately DM 300,000.00 to 500,000.00 per centrifuge machine.
The screw of the present invention may operate in an area of moist orujo or rape, because in that area a special separation of oil can be achieved by means of the blade segments. By use of the present invention, a solids mash can be fed into a bowl or drum preferably by way of a rectangular tube. The rectangular tube must be so long that the entering mass or mash to be centrifuged is charged or forced through an oil layer while being protected in order not to mix with the oil layer at a later time. In a filled centrifuge machine, an oil separation area may occur rather close to the screw body, for instance, at a distance of approximately 10, 20 . . . , to 40 to 50 mm. Fresh oil, as a distinct phase, can generally be recognized approximately in the range of 20 to 30 mm outside or away from the screw body. A distinct separating line usually exists here. The range of the oil separation area may vary with different centrifuges.
Charged solids, as part of a fed suspension, will therefore fill the centrifuge to such an extent that the latter is filled to the oil separation area (approximately 10-50 mm outside the screw body) with solids suspensions. The reason is that, as a rule, only so little water is in the orujo or rape mass that no water or only an extremely small layer of free water is formed between the oil and the solids suspension. In this case, the solids are dryer on the outside than on the inside or, in other words, a fraction of dry substance on the drum side is much higher than a fraction of dry substance toward the interior.
In the area of the recesses and blade segments, the solids suspension, just like the oil and an emulsion situated in-between, experiences three axial speeds particularly in a kneading area of the blade segments, from the screw body to an outside radial end of the blade segment.
Thus, a normal axial speed exists in the area of residual wall pieces or sections of the screw spirals. In contrast, in the area of the recesses, the axial speed is essentially zero. However, the axial speed in the area of the actual blade segments in the delivery path may amount to five times the normal speed. As a result, an elastoviscous sludge is deformed, compressed and relaxed in a standing solids area adjacent a surface of the drum.
In the area of the leading blade segments, for example x+1, x+2, x+3, x+4, the solids are additionally axially compressed. In the area of the recesses, they are then relaxed. This has the effect of pressure increases and relaxations. A setting-free or separation of the oil essentially takes place in a relaxation area and the extraction of oil is therefore more effective than without such relaxation areas.
In a rearward area, the screw body preferably has a cylindrical section and, in its adjoining forward section, a section which tapers essentially conically in a uniform or non-uniform--for example, stepped manner. The recesses and blade segments are constructed only in the area of the cylindrical section.
In the cylindrical section, the screw body preferably first has at least one screw spiral which is constructed without recesses as well as without blade segments and which is followed by additional screw spirals which are provided with the recesses and blade segments. It is also conceivable that optional oil drainage ducts are constructed preferably in the first screw spiral. The recesses preferably have a residual section of the screw blade on the circumference of the screw body. Relative to one or several screw spirals, the blade segments may be uniformly, or may be non-uniformly, distributed on the circumference of the screw body. The area of the recesses may amount to approximately 25-60%, preferably approximately 40-50% of the screw spiral area. The recesses in the screw blades may be constructed such that they radially project at least beyond the solids area (for example, 70-95%, preferably 70-100% of the screw blade height). The height of the blade segments may be approximately 0-30% lower than the height of the screw blade. The blade segments may be constructed as rectangular metal plates. Trapezoidal, rounded elements and/or elements shaped to be tapering or widening and extending from the screw body radially outward or to the outside are also conceivable.
FIG. 1 illustrates a screw 1 for a solid-bowl screw-type centrifuge 50 (see FIG. 3), the screw 1 having a screw body 3 as well as, in this case, a screw blade 5 which surrounds the screw body 3 several times and forms several screw spirals (for example x, x+1, x+2, etc.). A delivery path 7 for delivering/conveying a material to be centrifuged is formed between the screw spirals x, x+1, . . . .
In a rearward area 40 the screw body 3 has a cylindrical section 9 and, in an adjoining forward area 45, the screw body 3 has a dry zone 33 or conically tapering section 11 that is essentially conical, uniformly or non-uniformly. In a transition area 43 between the cylindrical section 9 and the conical section 11, a retarder or disk 13 is placed on the screw body 3. This placement was found to be successful particularly in a two-phase separation process separating material into an oil phase and a water/solids phase. Such placement may not be required in a three-phase separation process when separating material into oil, water and solids phases. The two phase separation process is shown in FIG. 3. The three-phase separator process is not shown in the Figures.
The operation of a solid-bowl screw-type centrifuge 50 with screw 1, among other components, is as follows: As shown in FIG. 3 material S to be centrifuged is fed or guided through a centrally arranged, adjustable inlet tube 14 into an inlet chamber 15. From there material S may go through openings 17 into drum space 19. Drum 21 surrounds the screw 1. Inlet chambers 15 and openings 17, or special distributors, may be arranged toward the rearward end or area 40 of the cylindrical section 3 (see FIG. 1).
In the drum space 19, the material S to be centrifuged is accelerated to a rotational operating speed. Under the effect of the force of gravity, solids particles will be deposited on a wall of drum 21 within a very short time. The screw 1 may rotate at a slightly lower or higher speed than the drum 21 and may deliver centrifuged solids F toward the conical section 11 out of the drum 21 to the solids discharge 23.
In contrast, liquid L may flow to a larger drum diameter area at the rearward end or area 40 of the drum 21 and may be discharged at overflow 25. In a two-phase extraction process, liquid L may represent the presence of oil. In a three-phase extraction process, liquid L may represent the presence of oil and water. From a second screw spiral (x+1) to a fifth screw spiral (x+4), the screw 1 has recesses 27 in the screw blade 5.
In the embodiment of FIG. 1, these recesses 27 are constructed such that one or more axial ducts 28 may be formed in an axial direction which may extend, for example, from a second to a fifth screw blade 5. The ducts 28 may also be formed in a zigzag type manner or angularly with respect to a center axis y of the screw. An individual screw spiral x+1 etc. with recesses 27 and blade segments 29 is also conceivable.
In addition, blade segments 29 are arranged in the delivery path 7 formed between the screw spirals x+1, x+2 . . . of the screw blade 5. Blade segments 29 may be constructed as metal strips and which may have a trapezoidal shape which widens radially from an outer circumference of the screw body 3.
Blade segments 29 may be constructed during the cutting-off of material for forming the recesses 27. The blade segments may be placed in the delivery path 7 and may be fastened in the path 7 by welding or by an equivalent means.
The cutting-off of the blade sections or segments 29 may take place such that the screw blade 5 is cut out to the circumference of the screw body 3. However, as an alternative, a residual section 30 of the screw blade 5 may also remain standing at or on the circumference of the screw body 3. If the cutting-out takes place essentially radially with respect to the drum 21 and screw axis y, trapezoidal blade segments 29 are obtained. The screw blades 5 may also be constructed as rectangular or rounded elements or be shaped as tapering or widening elements extending from the screw body 3 radially outward. By a combination of recesses 27 and blade segments 29 in the delivery path 7, the efficiency of some centrifugal separating processes can surprisingly be increased.
A screw 1 construction with recesses 27 and blade segments 29 has been particularly successful in the field of olive oil extraction. A two-phase separation process in which the oil is separated directly from a solids/water mixture, had been particularly successful in the extraction of olive oil. Such a process is described in European Patent Document EP 557 758. The efficiency of this already excellent process can be increased by using the screw 1 of the present invention, to (see FIGS. 1 and 3): separate the oil as a liquid or first phase directly in a two-phase separating process from a second phase mixture of water and solids, reduced fruit, such as olives and avocados, are first guided in a solid-bowl screw-type centrifuge 50 through a first portion 31a of a separating zone 31 with one or several screw spirals x-1, x, . . . , in which the screw blade 5 has no recesses 27 and in which no blade segments 29 are formed in the delivery path 7, then, in a second portion 31b of separating zone 31, there is a passing through a screw area in which the recesses 27 are constructed in the screw blade 5 and the blade segments 29 are constructed in the delivery path 7, then the solids and the water are conveyed past the retarding disk 13 out of the separating zone 31 into a conically tapering section 11 or dry zone 33 of the screw 1 and out of the centrifuge 50 at discharge 23.
Different dimensions as well as alignments and arrangements of the recesses 27 and of the blade segments 29 were found to be particularly successful in practice. By the variation of these parameters, the mixing effects between the screw spirals x, x+1 . . . can also be varied, which has a direct influence on the efficiency of the separating process. These parameters are described below with reference to FIGS. 1, 2a and 2b as is the preferred position of the recesses 27 and the blade segments 29.
For discussion, the screw 1, as shown in FIG. 1, is viewed from the rearward area 40 of cylindrical section 9 toward the front area 45 of the conical section 11. The screw 1 has several screw spirals, for example x-1, x, in first portion 31a, and screw blades 5 are constructed to be continuous or free of recesses 27. Preferably, one or more screw spirals x-1, x . . . are constructed to be continuous. In this area 31a, no blade segments 29 are provided in the delivery path 7.
This first portion 31a of the separation zone 31 zone is followed by a second portion 31b where, for example, several screw spirals x+1, x+2, . . . x+4 are provided with recesses 27 and in whose spaces or in whose delivery paths 7, the blade segments 29 are in each case constructed or erected. The blade segments 29 may be welded on the screw body 3 or attached by other equivalent means.
The cylindrical section 9 extends maximally to a beginning of the conical section 11 of the screw 1. In the transition area 43, between the cylindrical section 9 and the conical section 11, the retarding disk 13 is arranged. In the conical section 11, the screw 1 may be constructed to be free of recesses 27 and no additional blade segments 29 may be arranged in the delivery path 7.
For each screw spiral x+1, x+2 . . . in the cylindrical section 9, there may be approximately 2-6, and preferably 4, recesses 27. Correspondingly, for each screw spiral x+1, x+2 . . . in the delivery path 7, there may be approximately 2 to 6, and preferably 4, blade segments 29. The blade segments 29 are preferably distributed uniformly on the circumference of the screw body 3 but may be distributed non-uniformly.
Relative to the center axis or the axis of symmetry y of the screw 1, the screw spirals x, x+1 . . . are each arranged at an angle or form an angle .alpha. with the center axis y (see FIG. 2a). The magnitude of the angle .alpha. (measured at a lower edge 75 of the screw blade 5) is approximately between 60 and 85 degrees.
In contrast, as shown in FIG. 2a, the blade segments 29 enclose an angle .delta. with the center axis or axis of symmetry y, which may be smaller than angle .alpha.. The angle .delta. is approximately between 40 and 70 degrees, and preferably approximately 50 to 55 degrees. It is recommended to align, in the last screw spiral, for instance, x+5 . . . of the cylindrical section 9 before the retarding disk 13, the blade segments 29 essentially parallel to the screw blade 5. The maximal differential between angles .alpha. and .delta., may be preferably approximately 10 to 11 degrees.
The recesses 27 each have an area and the sum of those areas is a total recess area. The screw spirals x, x+1 . . . each have a surface area and the sum of those areas is a total screw spiral surface area. The total recess area of the recesses 27 may amount to approximately 25-60% of the total screw spiral surface area, and preferably 40-50%.
As shown in FIG. 2a, angle .delta. may be defined or determined such that a distance d (viewed as an axial extension of edges) between a blade segment edge 76 and a recess edge 77 is approximately 0 to 5 mm, and preferably approximately 2 to 3 mm. The distance d viewed from the screw body 3 becomes smaller with an increasing height of the blade segment. In the case of a trapezoidal shape of the blade segments 29, the size of any distances "d" as measured from the screw body 3, varies radially away from axis y and screw body 3 toward an outside position nearer a wall (not shown) of the drum 21. Distance "d" becomes, for example, larger toward the outside position.
Furthermore, angle may be defined or determined such that a distance A (see FIGS. 2a, 2b) viewed as an orthogonal extension of edges, between a longitudinal edge 78 of the screw blade 5 and the edge 77 of the recess 27 amounts to approximately 0 to 28%, and preferably 15 to 25%, of a distance z (See FIG. 2a) between an adjacent pair of screw spirals, for example x+2 and x+3, preferably viewed at the low end of the screw (inside), as a function of the shape.
According to an embodiment of the present invention, the blade segment 29 may be arranged in the delivery path 7 such that center axis M (see FIG. 2a) is situated precisely in the center of the delivery path 7, as well as preferably also in the center of a connection line C, having segments C/2, of the apothem of the recesses 27 at a crossing point of opposite recess edges (not defined).
As an alternative, it is also possible to shift the center axis or center point M of the blade segments 29 with respect to the preferable position as stated above.
A height h (see FIG. 2b) of the blade segments 29 (measured from the outer circumference of the screw body 3) is particularly decisive for the efficiency of the present invention.
According to the present invention, the height h of the blade segments 29 may be selected such that the segments 29 extend into an area where solids are present, or solids area 47, during centrifugal separation. Correspondingly, the screw blades 5 should have recesses 27 which radially project at least above the area of the solids area 47.
For example, in a case of centrifugal separation, solids are deposited relatively far to an outside or solids area 47 in the drum 21. If the blade segments or paddles 29 do not at least extend into this solids area 47, their efficiency remains low. A mixing effect of the recesses 27 and of the blade segments 29 in this solids 47 area clearly increases the efficiency of the centrifugal separation during the extraction of oil.
In practice, the height h (see FIG. 2b) is selected to be approximately 0-30% lower than a screw blade height k. Thus, a radial course (not shown) of the recesses 27, or, in effect, height h, amounts to approximately 70-100% of the height k. In addition, the screw blade 5 encloses an angle gamma with a circumferential wall 79 of the screw body 3, as shown in FIG. 2b. This angle gamma is preferably smaller than an angle at which the blade segment 29 forms with the screw body 3.
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 screw conveyors in centrifuges.
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