CA1110491A - Fat recovery system - Google Patents

Abstract

ABSTRACT OF DISCLOSURE
A fat recovery system for hide fleshings and trimmings is disclosed having a grinder for comminuting the fleshings and trimmings, the same being oriented to deliver its parts into a cooker having a steam jacket tube with an interior screw conveyor.
After the particulate material has passed through the cooker, a drum type rotary screen is provided from which fat will drop, and the particulate materials pass into a press. Thereafter the solid particulates are removed and the liquid products are delivered into a settling vessel which is heated by steam pipes.
Optionally, a drying tank may also be provided. The method of the subject invention essentially includes comminuting the fleshings and trimmings, passing the same through a confined passageway, and agitating the same simultaneously to prevent the particles from coalescing. Thereafter, the particles are screened, and the remaining solids passed into means for pressing the same. Subsequently, all of the output is passed into means for retaining the same, and heating the same, while introducing water or other fluid on which the fat will float in order to separate the fat form the particles. Thereafter, the fat product may be dried in an additional step,

Description

22 `
23 I FIELD OF INVENTION , , _ 24 The present invention relates generally tfO systems and methods for rendering fat ~rom the fleshings and trimimings of 26 hldes whether hog hides, steer hides, or any other type hide, a 27 slgnlflcant portion of such fleshings and trimmings containing 28 entrapped fat to be recovered.

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''' ~3Lh~491 l cooking in heatea vessels, with some agitation in order to promote

2 the separation of the fat ~rom the fleshings or tris~nings. The

3 particulate residue is then screened, sieved, or otherwise

4 physically xemoved from the rendered fat, and thereafter the fat is combined with water in order to stratify the sasne for separa-6 tion. In such methods or systems, there is a distinct possibi-7 lity that the particula-te ma-terial will coalesce, and form 8 larger clods of solids. The larger -the particle of solid, parti-9 cularly if much more than 3/8" -to l/2", the more fat remains en-trapped, and the more difficult it is to remove the fa-t by applyiny heat. At temperatures sigrlificclrltly above that of 12 boiling water, thc fat may change l.n its consi.stcncy, or composi-13 tion, and the particulatc soJ.i~s tend to cook alld b~lrn, tilUs 14 contaminating the pure at.

16 SUMM~RY
17 A fat recovery system and method is disclosed in which 18 the fleshings and -trimmings are first co~ninuted by a grinder, 19 preerably to a si~e approximating 3/8". Thereafter the same are passod throucJsl a cooker ha~incJ at least one steam jacketed tube 21 with an interior scr~w conveyor, the purpose oE the la-tter being 22 to move the particulate material through the cooker and at the 23 same time agitate the particulate material to an extent that 24 coalescence is significantly reduced, and the particulate inte-grity of the ground fleshings and trisl~lnys is main-tained.
26 Thereafter the particulate material is separated fr.om the fat 27 by delivering the output of the cooker to a screen, preferably 28 a cylindrical rotary screen. The fat drops into a collec-tor, and 29 the par-t~ulate mat~rialin-to a press, with -the liquid output oE -the press being delivered in-to the fat conduit and -the same conveyed ~-i49~L

l to a settling tank. The settling tank is heated, while water is 2 introduced, to maintain the fat ln a floating condition above 3 the water while the particulate material settles. Thereafter 4 means may be provided for draining the water and remaining parti-culate material, and optionally transferring the fat to a further 6 receptacle for drying. The method comprises essentially the 7 steps of fat recovery from fleshings and trimmings which included 8 comminuting the same to a particle size, preferably 3/8", cooking g the same while agitating in a longitudinal path to maintain the particulate integrity of the fleshings and trimmings, and there-ll after screening or sieving the particulate material into a press, 12 and diverting the fat to a conduit. Subsequent1y,most o~ the par-13 ticulat~ material is removed Erom the press ancl the fclt produced ~4 by pressing is delivered to a settlincJ area, heated, ~ncl mixed with water so that the fat will float. Subsequently the fat is 16 removed and dried for storage and shipment, and the remaining par-17 ticulate material may be recycled, or dried and disposed of as 18 protein.
19 It is a principal object of the present invention to provide a Ea-t recovery system and method which removes essent~ly 21 all o~ the ~at ~rom ~leshings and trimmings, and in addition, driec 22 the remaining particulate rnaterial to the end that it can be 23 processed for use a~ a source of pro-tein, or otherwise disposed of 24 A related object of the present invention is to provide a fat recovery system including a plurality of tubular cookers -26 having logitudinal conveyors which maintain -the particulate 27 inteyrity of the fleshings and trimmings while the same is cooked 28 to remove the fat.
29 Still another object of the present invention is to provide a fat recovery sys-tem and method which reduces any .' . . ' ~ ~ G / / 1.) / ~) G ~

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1 tendency to produce noxious odors and fumes, and at the same 2 time results in an economical recovery oE the fat product, as well as the particulate material.
4 Still another object of the present invention is to provide a fat recovery sytem for hide fleshings and trimmings 6 which is economical to construct, simple -to monitor in its opera-tion, and readily controllable with simple instrumentation, and 8 routine observation by an operator.
9 Yet another object of the present invention is to provide a fat recovery system and me-thod which is susceptible of batch r 11 operation, and in which the start-up and operating expenses are 12 minimized due to the utili~ation o.E steam, and electrica:L motors 13 ~s thé sole ~ource o~ indeperldent app:Lied ellercJy.
1~ Yet another objec;t o the present invention is to provide a fat recovery system for hide fleshings and -trimmin~s, the 16 operation and use of.which produces.a..fat which has not.been sub-.
17 jected to unduly elevated -tem~eratures.,..and.thus pure in form, and 18 similarly produces a concentrated pro-tein form of fleshings and r 19 trimminys which are readily marketable 20 Y~t another important object o~ the present .inven-tion ~1 is to provide a ~at recove.ry syst~ln an~ metllod which involves a 22 minimal arnount of Eine tolerances, thereby permitting the trans-23 port and the settling of dirt, oEal, and other contaminants at 24 the settling terminus of the system and method to thereby cleanse the ultimate fat product.

28 F.urther objects and advantages of the present invention 2~ will become apparent as -the following descrip-ki.on of an iIlus-trative embodiment proceeds, taken in conjuncti.on with the ~ o / J ~ u / J ~ ~

1 accompanying drawings in which:
2 FIG . 1 is a flow sheet showing the sequential elements 3 employed in the system and the steps embodied in the method.

DESCRIPTION OF PR~FERRE D SYST~M
. - - _ 6 The subject recovery system 10, as shown in its entirety 7 diagrammatically in FIG. 1, presupposes a hide from which the 8 flesh and trimmings have been collected. This may be accomplished 9 in standard scraping, skinniny, and other techniques. The hides may be fresh or cured. The recovery system 10 beg:ins with a 1 grinder 11, having a yrinder hopper 12 in-to which the fleshings 12 and tril~lincJC; are irltroduc~d. ~rlle grirlcler i.s selectcd from that 13 typ~ o~ grincler availabl~ to insurc that the l~arti.culate si~e o~
1~ the EleshincJs or tri~nings is :reducecl to 3/~" or less prior to delivering the same into the output. A typical grinder motor 14 16 and grinder pump 15 drive the unit, with the exhaust or discharge 17 portion of the grinder 11 dropping into a pump hopper 19.
18 ~hereafter the pump motor 18 and grinder pump 15 drives the 19 discharyed~material through the particulate conduit 16, and towards the cooker 20. A steam inlet 21 is provided in the 21 particulate conduit 16 on the ~ischarge sicle of th~ cJrinder 22 pump 15~ Generally a 1~2" or 3/4" stem inlet pipe is sufficient 23 however, the size and number of steam inlets is dependent upon 24 the distance and quantity oE the material to be pumped. The steam inlet is injected at substantially a 45 angle with the 26 particulate conduit 16 so that the steam will assist in driving 27 the particulate raw material to the cooker 20 as well as 28 preheating the same.
29 The cooker 20, as noted in the upper left hand portion o~ FIG. 1, is shown as comprising an upper steam tube 25, a .

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l middle steam tube 26, and a lower ~team tube 27. Interiorly of 2 each of the steam tubes 25, 26, 27, a half pi-tch screw conveyor 3 28 is positioned, having its own screw conveyor drive 29. The 4 half pitch screw conveyors or augers are commercially available as manufactured by Screw Conveyor Pacific Co., Visalia,California.
6 Steam jackets 30 are provided in surrounding cylindrical relation-7 ship to the interior portion of the steam tubes 25, 26, 27, said 8 steam jackets normally carrying a dry steam from a conventional g boiler at approximately 90 psig and 320F. A pressure relief valve and condensate drain (no-t shown) is also normally provided. The ll pressure and temperature o~ the stearn can ~c var.ied such that 12 proper cookiny o the particu:Late material occurs witllout undue 13 waste of steam. ~rhe ~team jacket and tube~: arc col~unerc.i~l:ly avcliL-14 able as manufactured by Canal Boiler Works, Seattle, Washington.
A clearance is provided between the half pitch screw conveyor 28 16 and the interior of the steam tube to permit relief for the 17 passaye of contaminants such as sand, clay, ofal, residual hair, 18 and the like. A screw conveyor drive 29 is provided at the end of 19 each o the half pitch screw conveyors 28 so that the s~le are driven at substalltially the same speed o~ rotakion.
21 To be noted is the provision oE an upper transEer tube 31 22 from the upper steam tube 25 tothe middle steam tube 26. The 23 upper transfer tube 81 conveys the cooked material from the upper 24 steam tube 25 into the middle steam tube 26. In the middle steam tube 26, the particulate material is continually cooked 26 but moves in a direc-tion contra to the direction of the upper 27 steam tube 25. After passing through the middle steam tube 26, 28 a lower transfer tube 32 is encountered which drops the thus 29 cooked product into the lower steam tube 27. Because -the upper, middle, and lower steam tubes 25, 26, 27 are oriented in vertical l~/ j 4-21- /~ 19~
"'",.,~ ' 1 fashion, a single exhaust manifold 35 is provided in coupled 2 relationship to each of the steam tubes 25, 26, 27 to vent the 3 interior to atmosphere. By the time the particulate has passed 4 through the three steam tubes 25, 26, 27, the same is discharged by fluid gravitation flow through the discharge tube 34 into the 6 rotary screen 40. Prior to the discharge, it will be noted that 7 the lower exhaust feed 36 is adjacent the discharye tube 34 and 8 immediately thereabove, leading into the exhaust manifold 35.
9 In addition, a middle exhaust feed 38, and upper exhaust-feed 39, are provided at ends o~ the respective steam tubes 25, 26, 27.
r 11 Preferably the exhaus-t feeds 36, 38, 39 are provided at the dis-12 charge portion oE the steam tubes 25, 26, ~7 so thclt they do not 13 lnk~r~ere with tlle eed tube to ~he par~icu:lar st~am tube.
14 The rotary screerl 40 is driven b~ means Oe the screen lS drive 41, and posi-tioned to rotate along a genera~ly horizontal 16 axis, with the axis sloping downwardly at an accute angle with 17 the horizontal to the end that the particulate material will be 18 transported across the rotary screen 40. The size of the ro-tary r screen 40 varies with the desired production. A standard ! 20 commercially available size is lSI' diame-ter, 48" long and 21 12-15 mesh. A vibrating screen with 50-~0 mesh and 48" diameter 22 could also be used, wllich is commercially available from Sweco 23 Manufacturing, Los ~ngeles, California. The fat which drains 24 drops into the screen hopper 42. At the lower portion of the screen hopper 42, provision is made for a screen hopper fat dis-26 charge 44 which connects at a fat connector 52 to the mixed 27 discharge conduit 54. The balance of the partic~llate matter 28 passing through the rotary screen 40 drops into -the press hopper 29 22. The press 45 has an in-terior press auger 46 with a decreasing pitch diameter, and optionally a decreasing pitch. The same ~ 9L9~L

1 is driven by a press auger drive 48 to carry the particulate 2 material through the press. The fat and water is extruded 3 through slots in a cone 47 which encompases the auger 46. The slots are approximately .003" wide, 1/2" long, 3/8" apart, and cover the entire cone. The cone is yeneral~y made of 3~16"
6 stainless steel; however, other materials could be used. The 7 solids are conveyed to the end of the press and are dischar~ed 8 at a press solid discharge point 53. The tapered auger Elights 9 49, as commented upon, have a decreasing pitch diameter and optionally a decreasing flight proportion. The fat and water 11 extruded by the press ~5 -then drops down throucJh the liquid 12 pres~ discharge 50 in~o a prcss discllarcJe condult 51 and tl-ence 13 to the ~at coll~ecto~ 52 allc-l ollwE~rdly tllroucJII thc mi.xed cll.scl~alc 1~ conduit 5~ to the discllarcJ~ pump 55. rl'he disc~larc~e pump 55 carries the combination of remaining solids, Eat and water 16 con-tinuing throuyh the mixed clischarye conduit 54 into the 17 ¦ settling tank 56. ThereaE-ter the product can be transferred 18 ¦ into the drying tank 58 as will be described hereinafter.
19 ¦ ~ preferably convoluted steam coil 60 ls positioned ¦ int~riorly oE the settLiny tallk 56, and heated -to a temperature 21 ¦ somewhere between 180F an~ 200L~'. In this mclnn~r the settlincJ
22 ¦ tank 56 is heated as it is beincJ filled. :[E s~paration of the 23 ¦ fat and water has taken place, the steam coil 60 is turned 24 ¦ off. If separation has not yet taken place, the steam coil 60 ¦ is left on until it does. The steam coil 60 thus maintains the 2~ ¦ fat in a liquid condition, and thereafter as water is intro-27 ¦ duced in-to the settling tank 56, the par-ticulate ma-terial 28 ¦ will drop to the lower portion where i-t can be removed at the 29 ¦ settliny tank discharge 65, and in the meantime the fat separates ¦ and floats above the water ~t -the lower portion of the settling ~ /J ~ G - ~ L l~
''''.,' 1 tank 56. The particulate material removed at the settling tank 2 discharge 65 are recycled by being mixed with the raw materials 3 going into the cooker.
4 Once the fat has adequately se-ttled from the particulate material and floa-ted upon the wa-ter, a fa-t -transfer tube 61 is lowered into the settling tank 56, and the fat transfer pump 62 activated to transfer the fat throuyh the fat transEer discharge 8 64 into the drying tank 58. The drying tank 58 may be optionally g heated by an additional steam coil as with the steam coil 60 in the settling -tank 56, or otherwise ayitated or trea-ted to 11 remove residual water from the fat. The purpose of the drying 12 tank 58 is tQ remove any excess moisture throucJh evaporation.
13 Tllcrea~ ter tllc Eat contain~d in the dryincJ tcll~k 5~ is div~rt~d ~y 14 moans o th~ fat ~i~char~Je 66 into permanent s~orage, or p~ckacJ-ing, or other containerizatiorl for shipment, or op-tionally for 16 further processing.
17 The process is desiyned to be most efficiently opera-ted 18 as a con-tinuous process up to the se-ttling tanks where some ;
19 retention time is required to allow the par-ticula-tes -to settle from the fat and water. The system can be designed for any 21 desired capacity by increasincJ the equipmcnt or adding equipment 22 to an existiny system.
23 A -typical system using -three s-team tubes, each 10" in 24 diameter by 10 feet long,will handle 7,000 to 8,000 pounds per hour of raw material. This amount of raw material would yield 26 approximately 1,300 pounds of fat and 700 pounds of solids 27 (wet bases) per hour. The amounts vary as they are dependent 28 on the size, type of hides, and the amoun-t of Eleshings on the 29 hides. The quality of the finished fat one could expect is basically-.
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1 F.A.C. COLOR: 3-5 2 Titre: 37C
3 Free Fatty Aclds: .005%
4 .
S THE METi~OD
6 The method of the present invention contemplates first 7 removing fleshing and -trimmings from a cured or fresh hide. The 8 fleshings are then comminuted into a size less than l/2", pre-9 ferably 1/8". The means for comminuting are confined in such a fashion that any fat which is pressed from the particulate 11 material at the time is conEined and conveyed.
12 ThereaEter, the particulate mater.ial. is introduccd into 13 a cooker provid:iny a~ollcJitudinal or horizontal passageway in 14 constant acJitation, ~ubject to a temperature apl~roximatinc~ that o~ live steam. The confinemen-t, however, is provided with a 16 further step in venting the same to atmosphere to prevent 17 pressure build-up, or pressure cooking. Irhereafter~ the 18 particulate ma-terial is separated from the thus rendered fat, 19 and the particulate ma-terial further pressed -to remove residual entrained fat.
21 A Einal step contemplates the transfer of the combined 22 ~at and particul.ate material into mearls for separating the same 23 by water floatation, with the further imposed ste~ of maintaining 24 the fat portion at the upper portion of the settling means at a temperature between 180F and 200F to promote the settling, and 26 to maintain the fat in -the fluid state. Thereaf-ter, the fat is 27 transferred to a further confined area for drying, while the 28 particulate material is removed by discharging the same with the : 2~ water.
In review it will be seen tha-t a :Eat recovery system has 11~9~

1 been shown and described for fleshings and trimmings of cured 2 and fresh hides which constantly agitates particulate material 3 to the end that a total cooking takes place removing the 4 majori.ty of the fat from the particulate material. In addition, however,. the particulate material is further pressed to remove 6 residual fat. Therea~ter, a settling means separates the fat 7 from the par-ticulate material prior to final processing.
8 ~lthough particular embodiments of the invention have 9 been shown and described in full here, there is no intention to thereby limit the invention to the details of such e~bodi-11 ments. On the.contrary, the intention is to coVer all modifi-12 cations, alternativcs, embod:irnellts~ USa(JeS alld equ:i.valents of 13 a l.at recovery sy~tem .IS .I.clll withill tlle spiri~ and scoue o~

th~ inventioll, sp~ci.~icatiorl and thc apperl~ed cla:im~;~
16 _ 17 _ 18 _ f~ lg _ r~ 20 _ _ 26 _ 27 _ 28 _ _

Claims (18)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A fat recovery system for hide fleshings and trimmings comprising, in combination, a grinder for comminuting material of fleshings and trimmings to a pre-determined particulate size maximum, a cooker having at least one steam jacketed tube with an interior screw conveyor, means for transferring the comminuted material of particulate fleshings and trimmings from the grinder to the cooker, means for driving the screw conveyor to pass the material particulates through the steam jacketed tube while heating the same, discharge means for the comminuted material and separated fat from the steam jacketed tube, a screen receiving the discharged material and fat from the tube, fat collecting means to receive fat passed through the screen, a continuous screw press receiving the material particulates not falling through the screen to further press the particulates to further remove the fat into a common conduit with the fat discharged from the fat collecting means, a discharge means at substantially the end of the press to remove the residue particulates and a heated settling reservoir receiving the fat and residue particulates, whereby water may be introduced into the settling reservoir to float the fat on top and wash the particulates to a lower portion of the settling reservoir.

2. A system as claimed in Claim 1, comprising at least three such steam jacketed tubes connected in series.

3. A system as claimed in Claim 2, said tubes being horizontally disposed in a vertical tier to provide for passage of the particulates being cooked from top to bottom.

4. A system as claimed in Claims 1, 2 or 3, wherein said screen is a driven rotary cylindrical member driven along an axis at an acute angle with the horizontal.

5. A system as claimed in Claims 1, 2 or 3 comprising a drying tank and means for transferring fat from the upper portion of the setting reservoir to the drying tank.

6. A system as claimed in Claims 1, 2 or 3, further comprising exhaust means coupled to said jacketed tube whereby the interior of the tube is vented to the atmos-phere while cooking and particulate transfer proceeds.

7. A system as claimed in Claims 1, 2 or 3 comprising a steam inlet in open communication with said means for transferring the comminuted material.

8. A system as claimed in any one of Claims 1, 2 or 3 wherein said press has a decreasing pitch auger and a taper-ing mating side wall portion.

9. A system as claimed in Claims 1, 2, or 3 further comprising means for recirculating the fines from the settling reservoir back into the cooker to further separate the fat from the other materials in the fines.

10. A system as claimed in Claims 1, 2 or 3 further comprising means for recirculating through the system the fines from the settling reservoir whereby further fat may be separated from the fines.

11. A system as claimed in Claims 1, 2 or 3 wherein the steam is introduced into the comminuted material in the direction of flow of said comminuted material and further assists in transferring said material from the grinder to the cooker.

12. A fat recovery system for hide fleshings and trimmings comprising in combination, a grinder for comminuting material of fleshings and trimmings to a predetermined par-ticulate size maximum, a cooker having at least one steam jacketed tube with an interior screw conveyor means for transferring the comminuted material of particulate fleshings and trimmings from the grinder to the cooker, said means comprising an inlet for introducing steam in the direction of flow to preheat and to assist in transferring said material from the grinder to the cooker, means for driving the screw conveyor to pass the material particulates through the steam jacketed tube while heating the same, discharge means for the comminuted material and separated fat from the steam jacketed tube, a moving screen receiving the discharged material and fat from the tube and permitting water and other fluids to pass directly into the settling reservoir, a press receiving the material particulates not falling through the screen to further press the particulates to separate fat from the same, a discharge means at substantially the end of the press to remove the residue particulates, a heated settling reservoir receiving the fat and residue particulates whereby water may be introduced into the settling reservoir to float the fat on top and wash particulates to a lower portion of the settling reservoir and further including means for recirculating the fines from the settling tank, whereby further fat may be separated from the fines and the polluting effect from disposing of such fines in minimized as the same will ultimately separate into fat and particulate material, the latter being processed by the press.

13. In the system of Claim 12, said screen being a driven rotary cylindrical member driven along an axis at an acute angle with the horizontal.

14. In the system of claim 12 or 13, a drying tank, and means for transferring fat from the upper portion of the settling tank to the drying tank.

15. In the system of Claim 12, 13 or 14, exhaust means coupled to said jacketed tube whereby the interior of the tube is vented to the atmosphere while cooking and particulate transfer proceeds.

16. A method of fat recovery from hide fleshings and trimmings comprising the steps of, comminuting the fleshings and trimmings material to a size less than 1/2" confining and cooking the thus comminuted fleshings and trimmings material while transporting the same in constant agitation in an atmospherically vented pathway, screening the fat and the residual particulate material after cooking, collecting the fat separated by screening, pressing the remaining particulate material in a zone in fluid communication with the separated fat, removing pressed particulate material, combining the fat collected from the pressed particulate material with the fat separated by screening and diverting the combined fats into a settling area, heating the settling area after and during passing water into the same to a temperature between 180°F and 200°F, and thereafter removing the thus separated Eat from the settling area.

17. A method according to Claim 16, comprising the additional step of passing the material through three separate cookers, sequentially and in vertical orientation.

18. A method according to Claim 16, or Claim 17, comprising the step of transferring the fat from the settling area into a drying area and the further step of drying the fat in the drying area.