Process for de-boning meat or fish

Abstract

material obtained from animals, poultry, or fish and containing edible flesh along with normally inedible relatively hard or tough components, such as bone, gristle, tendons, etc., is fed in ground condition into one end of a perforated conduit that has a conveyor screw therein which progressively decreases in conveying capacity from the feed end of the conduit to an imperforate discharge end thereof. Such inedible components are compacted within the imperforate discharge end of the conduit by an extension of the conveyor screw prior to discharge following build-up and conveyance along the interior surface of the perforate portion of the conduit as a filter mat through which edible flesh is forced toward and through the perforations of the conduit to provide a substantially bonefree edible product. The discharge passage surrounding the extension of the conveyor screw can be varied in size, preferably by a tapered ring that is movable back and forth axially of the conveyor screw extension, and preferably the spacing between conveyor screw and conduit is variable. The forward faces of the conveyor screw flights are preferably concave to provide a forwardly projecting circumferential overhang that tends to keep particles of bone near the axis of the screw, and the conduit wall thickness is unusually thick so as to withstand high pressures. Unusually high production rates can be obtained by feeding finely ground material into the conduit by means of a high pressure pump. The discharged and normally inedible components can be slurried in a digestant liquid and the digested material recovered as a food product by the application of centrifugal force. In instances where some minute particles of bone are discharged with the fleshy components, they can be homogenized by subjecting such flesh fleshy components to an attrition operation.

Description

RELATED APPLICATIONS

The present embodiment apparatus embodiments of the invention. Circumferential flanges 19c are preferably provided at opposite ends, respectively, of the perforated area as guides for the extruded meat product.

Both conduit 19 and its coacting compression screw 16 are preferably tapered from feed end to discharge end, as just indicated, to provide for positioned adjustment of such screw in the conduit to compensate for wear and to provide variations in spacing from conduit wall surface as may be desired. The taper may be slight, e.g. from 5 to 10%, or may be great so that the configuration is more conical than it is cylindrical. In any event, the spiral valleys 16b between flights 16c of such screw 16 become progressively more shallow, so the screw progressively decreases in conveying capacity and acts with increasing force to press the conveyed material outwardly against the perforate wall of conduit 19.

As soon as the feed material from grinder 10 enters the smaller diameter de-boning conduit 19 in ground condition, it is pressed outwardly under moderate pressure. The material emerging from perforated cutter plate 17 into the feed end of perforated conduit 19 is under pressure, which, contrary to the case of a conveying scew (like 12) alone, without a cutter plate, is maintained within conduit 19 because of the confining nature of such cutter plate relative to back pressure within the conduit. Such pressure progressively increases as the material travels along the length of screw 16. The pressure causes fibrous boney bony material to mat, albeit thinly, at the inner wall of conudit 19 and across perforations 22 before any significant quantity of the relatively soft meat material can escape, and thereby immediately commences to filter boney bony material from such soft meat material as the latter is squeezed from the valleys 16b through the mat and thence through the perforations 22. The mat progressively increases in thickness along the length of the screw and is carried along by the screw to the discharge end of the separation chamber, where it is forced into and through the previously mentioned discharged valve arrangement 23.

Such valve arrangement comprises a tapered discharge extrusion extension 16d of compression screw 16 that projects beyond perforated conduit 19 and extends along the passage formed by the imperforate discharge end 19b of perforate conduit 19 and by the telescoped discharge ring 21. Between such elements 19b and 21 and the tapered discharge extension 16d of compression screw 16 is formed a restricted, annular, discharge passage 24, through which the final mat of boney bony material passes in discharging from the machine.

Discharge ring 21 has an interior taper that is slightly greater than the taper of discharge extension 16d of screw 16, so that, as the end 21a of the ring is screwed farther into the imperforate discharge end 19b of conduit 19, the size of the annular discharge passage 24 of valve 23 is decreased. This passage thus provides a variable restriction to flow of the mat of boney bony material circumferentially of the discharge end of conduit 19. The pressure in the separating chamber will be dependent upon the size of this discharge passage 24 as determined by the position of discharge ring 21. Thus, it is apparent that both the edible meat components and the normally inedible boney bony material components are separately extruded from the machine under the control of ring 21 serving as an adjustable discharge valve element.

Extension 16d, as illustrated, FIG. 2, advantageously has a smooth outer face and channels 23a extending longitudinally to form screw flights and valleys therebetween for the elongate, annular, discharge passage 24 of the valve. Such passage 24, as indicated, preferably has an initial chamber portion 24a that feeds into the portion defined by the discharge ring 21 by way of an abrupt annular shoulder 21b, thereby establishing an elastic ring or choke of boney bony material in such chamber portion 24a that tends to compensate for variations in percentage of boney bony components in the material being de-boned.

A reversible ratchet is advantageously employed to screw discharge ring 21 farther into or farther out of conduit 19. For this purpose, such ring 21 is formed as a ratchet wheel with notches 25 about its exterior periphery. An operating ring 26 fits around dicharge discharge ring 21 and is rotatable relative thereto by means of a handle 26a. Resiliently biased in conventional manner within a knob member 26b of such operating ring 26 is a pawl 27. To reverse the pawl so that discharge ring 21 can be screwed in a reverse direction, it is only necessary to turn knob member 26b, as is customary in ratchet construction of this type, there being no need to go into further detail in view of the well known nature of this mechanism.

For both journaling the discharge end of compression screw 16 and enabling its position within conduit 19 to be adjusted to compensate for wear or to increase or decrease the spacing between conveyor screw and conduit, a plate 28 equipped with a central bearing 29 is rigidly supported in fixed spaced relationship with discharge ring 21 by means of pins 30 extending longitudinally from fixed securement in flange 19c of conduit 19. The discharge end of extension 16d of compression screw 16 is reduced in diameter and provided with a stub shaft extension 31, FIG. 2, having a journal portion flanked by threaded portions on which are respective adjusting nuts 32 and 33. These nuts are normally cinched tightly against bearing 29 to prevent axial movement of compression screw 16, but when wear of the flights 16c has increased the desirable tolerance between screw and conduit it is only necessary to loosen nut 33 and tighten nut 32 to effect the adjustment. This arrangement also permits such tolerance to be increased or decreased as may be desired.

Often fleshy muscle material passing through perforations 22 of conduit 19 is fibrous and exerts a strong drag on the material being transported axially of compression screw 16 toward discharge passage 24. In order to eliminate or significantly ease this drag and so increase throughput capacity of the machine, it is sometimes advantageous to position one or more knife blades across the flights of the screw, so as to extend axially of the screw at the outer periphery of such flights. Thus, as shown in FIGS. 8 and 9, knives 34 and 35 are freely inset into receiving notches 36 in the flights 16c of the compression screw 16 of this alternative embodiment of the debonding machine with the back of each knife abutting the back 36a of its notch, the blade resting on the upwardly sloping bottom 36b of the notch, and the sharp edge bearing lightly against the inner wall of the conduit 19 in shearing relationship with the edges of perforation 22. The shearing angle should be small to prevent or minimize scoring of such inner wall of conduit 19.

In operation, the knives 34 will cut the fibers that create drag, but will not destroy the filter mat that covers the perforations exposed to the valleys 16b between flights.

In this connection, attention is called to the double meat grinder of Ardrey U.S. Pat. No. 2,841,197, which has a somewhat similar construction, but is not intended nor adapted for the de-boning of meat that is ground together with boney bony components.

In accordance with the process of the invention as depicted diagrammatically in the flow sheet of FIG. 10, raw carcass material is ground before being fed into the de-boning machine, which separates a high proportion of the relatively soft fleshy components from the harder boney bony components. The former constitute a finished meat product; the latter, in matted form, can be used for both stock or animal feed or can be processed further, as indicated by broken lines, by digestion of protein constituents through the addition of a protein digestant and by passage through a centrifuge to eliminate undigested boney bony components.

In instances where higher de-boning pressures are used, by setting of the discharge valve of the de-boring de-deboning machine to narrow the discharge passage 24, so that more bone particles pass through the filter mat than can be tolerated in a commercial meat product, the resulting inferior meat product is passed through a colloid mill or other apparatus for effecting homogenization by attrition to produce a stabilized colloidal meat emulsion in which the bone particles have been so disintegrated as to be harmless.

It has been found that enormously increased throughput, without significant decrease in de-boning effectiveness, can be achieved by forced feed of finely ground meat or fish materials into the de-boning conduit under pressure, usually accomplished by means of a pump, and that other features to be described improve the effectiveness of the machine.

In the embodiment of FIGS. 11-14 a slurry of meat or fish material ground in standard equipment, e.g. a high extrusion type grinder whose extrusion passages are each five-sixteenths or three-eighths of an inch in diameter, is run into a hopper 40 equipped with double mixing screws 41 and 41a to keep the solids in suspension. The lower screw 41a feeds the slurry into the intake end of any suitable pump 42, for example a rotary vane, stainless steel, pet food pump as marketed by Auto Equipment Company, Astoria, Oregon, having its working parts specially hardened against bone abrasiveness. A conduit 42a conducts pump dicharge into the feed end of de-boning conduit 43, see especially FIG. 13, under pressure that may vary between about 5 to 250 lbs/sq. in., depending upon volume and character of feed and speed of rotation of the conveyor compression screw.

The conveyor compression screw 44 is similar to the corresponding screw 16 in the previous embodiments, but its stub shaft portion 44a is journaled in an imperforate entry section 45 of the perforated de-boning conduit 43 and connects with drive means 46 housed below hopper 40; also, the forward faces of its flights are made concave, as at 44b, to provide respective over hanging, forwardly facing, peripheral members 44c that tend to force fragments of boney material toward the axis of the screw. Perforated conduit 43 corresponds to conduit 19 of the previous embodiments, as do other components of the de-boning mechanism; including the dicharge discharge ring 47 and ratchet ring and handle 48 of the discharge valve. However, the compression-screw-journaling plate 49, and longitudinally extending supporting members 50, and imperforate discharge end 51 of conduit 43 are preferably made as a single casting, as shown, rather than separately as in the previous embodiments and are secured to the end of conduit 43 as by means of screw 52. Moreover, the attenuate pins of the previous embodiments have been replaced by the relatively wide members 50 to provide increased strength.

In order to enable precise adjustment of the discharge valve opening of conduit 43, a scale 53 is marked circumferentially around a rearwardly extending rim 47a of discharge ring 47 and a correlated scale 54 is marked longitudinally along one of the stationary supporting members 50.

The several new features noted for the embodiments of FIGS. 11-14 can be incorporated in the embodiments of FIGS. 1-13 if desired.

Whereas this invention is here described and illustrated with respect to certain preferred forms thereof, it is to be understood that many variations are possible without departing from the inventive concepts particularly pointed out in the claims.

Claims

1. A process for de-boning ground meat or fish material containing soft fleshy matter and boney bony components, comprising the steps of introducing under pressure such a material into the feed end of a perforated de-boning conduit of circular cross-section and open for discharge of material at the opposite end, said conduit containing a rotary compression screw extending along its length and through the open discharge end thereof; conveying said material toward said discharge end of the conduit by means of said screw while maintaining said pressure, so as to compress said material within said conduit, whereby boney bony components are retained in and passed along said conduit as a filter mat through which soft fleshy matter is forced toward and expelled through the perforations of the conduit; maintaining sufficient clearance between said screw and said perforated conduit to maintain a thin coating of said bony components on the inner wall portions of said conduit between said screw and said conduit; selectively restricting said flow from the discharge end of the conduit circumferentially of and around the discharge end of said screw to increase the pressure within said conduit; and positively passing said filter mat through said open discharge end of said conduit circumferentially of and by means of said discharge end of the screw for discharge from the conduit.

2. A process according to claim 1, wherein the material is introduced into the conduit under pressure by means of a meat or fish grinder.

3. A process according to claim 1, wherein the material is introduced into the conduit under pressure by means of a pump.

4. A process according to claim 1, including the additional step of varying the extent of restriction of the discharge of the boney bony components from the conduit.

5. A process for de-boning ground meat or fish material containing soft fleshy matter and bony components, comprising the steps of introducing under pressure such a material into the feed end of a perforated de-boning conduit of circular cross-section and open for discharge of material at the opposite end, said conduit containing a rotary compression screw extending along its length and through the open discharge end thereof; conveying said material toward said discharge end of the conduit by means of said screw while maintaining said pressure, so as to compress said material within said conduit, whereby bony components are retained in and passed along said conduit as a filter mat through which soft fleshy matter is forced toward and expelled through the perforations of the conduit; maintaining sufficient clearance between said screw and said perforated conduit to maintain a thin coating of said bony components on the inner wall portions of said conduit between said screw and said conduit; said coating constituting a portion of said filter mat; said clearance being maintained on the order of four one-thousandths of an inch; selectively restricting flow from the discharge end of the conduit circumferentially of and around the discharge end of said screw to increase the pressure within said conduit; and positively passing said filter mat through said open discharge end of said conduit circumferentially of and by means of said discharge end of the screw for discharge from the conduit. 6. A process for de-boning ground meat or fish material containing soft fleshy matter and bony components, comprising the steps of introducing under pressure such a material into the feed end of a perforated de-boning conduit of circular cross-section and open for discharge of material at the opposite end, said conduit containing a rotary compression screw extending along its length and through the open discharge end thereof; conveying said material toward said discharge end of the conduit by means of said screw while maintaining said pressure, so as to compress said material within said conduit, whereby bony components are retained in and passed along said conduit as a filter mat through which soft fleshy matter is forced toward and expelled through the perforations of the conduit; maintaining sufficient clearance about four one-thousandths of an inch between said perforated conduit and the flights of said screw to maintain a thin coating of said bony components on the inner wall portions of said conduit between said conduit and said flights of said screw; said coating constituting a portion of said filter mat; selectively restricting flow from the discharge end of the conduit circumferentially of and around the discharge end of said screw to increase the pressure within said conduit; and positively passing said filter mat through said open discharge end of said conduit circumferentially of and by means of said discharge end of the screw for

discharge from the conduit. 7. A process for de-boning ground meat or fish material containing soft fleshy matter and bony components, comprising the steps of introducing such a material under pressure between about 5 to 250 pounds per square inch into the feed end of a perforated de-boning conduit of circular cross-section and open for discharge of material at the opposite end, said conduit containing a rotary compression screw extending along its length and through the open discharge end thereof; conveying said material toward said discharge end of the conduit by means of said screw while maintaining said pressure, so as to compress said material within said conduit, whereby bony components are retained in and passed along said conduit as a filter mat through which soft fleshy matter is forced toward and expelled through the perforations of the conduit; maintaining sufficient clearance between said perforated conduit and the flights of said screw to maintain a thin coating of said bony components on the inner wall portions of said conduit between said conduit and said flights of said screw; said coating constituting a portion of said filter mat; selectively restricting flow from the discharge end of the conduit circumferentially of and around the discharge end of said screw to increase the pressure within said conduit; and positively passing said filter mat through said open discharge end of said conduit circumferentially of and by means of said discharge end of the screw for discharge from the conduit.