GB2093331A

GB2093331A - Method and apparatus for press-separating foodstuffs

Info

Publication number: GB2093331A
Application number: GB8204001A
Authority: GB
Original assignee: Nordischer Maschinenbau Rud Baader GmbH and Co KG
Current assignee: Nordischer Maschinenbau Rud Baader GmbH and Co KG
Priority date: 1981-02-25
Filing date: 1982-02-11
Publication date: 1982-09-02
Also published as: RO88676A; AU8044882A; BR8200927A; NL8200568A; DD205604A5; BE892192A; JPS57155940A; FR2500366A1; PL235213A1; DE3106992A1

Abstract

A method and apparatus for separating the fat and protein constituents of the flesh of warm- blooded animals and fish from non- edible parts such as sinews, skin and bones comprises passing the flesh between an endlessly rotating, highly elastic pressure belt (4) and a rotating perforated drum (1), the pressure being varied during the passage as the studs (9) on the belt are narrower than the grooves (7) on pressure roller (5) causing increased pressure at back surface of the studs and decreased pressure at front of the grooves. Pressure between belt and drum can be varied by altering axis (6) of the rotating roller (5). <IMAGE>

Description

SPECIFICATION Method and apparatus for press-separating foodstuffs The invention concerns a method and an apparatus for separating closely attached firm and flowable parts or constituents of a mixture, especially the fat and protein parts of the flesh of warm-blooded animals or of fish from inedible parts such as sinews, skin and bones.

A press separating machine for separating fish flesh is known (see NO Patent 60 653) which uses a perforated drum, part of its periphery being embraced by a flexible belt. The belt conveys the fish to be separated and for this purpose is provided with a roughening increasing the skid resisting properties on its outer surface facing the perforated drum. The pressure of the belt against the perforated drum results from the traction tension of the belt as well as from the radial rhythmic movement of a number of hammers against the perforated drum, the hammers supporting themselves by their working surfaces adapted to the curvature of the perforated drum against the inner surface of the belt turned away from the perforated drum. The hammers are driven by a crank mechanism in such a way that the hammers touch the empty running belt at their closest approach to the perforated drum.

After its entry into the entry gap between the perforated drum and the belt, the fish to be press separated causes the belt two be lifted so that the inner surface of the belt enters the effective area of the hammers, whereby the fish having reached the area of the hammers comes under the influence of a sinusoidally increasing pressure which effects the flowing off of the muscle flesh into the perforated drum. When the maximum pressure of the hammers in the arrest point of the crank mechanism has been exceeded, there is a release of pressure down to the residual pressure caused by the tensile stress of the belt, after which a new pressure cycle is started which reaches its maximum when the progressive movement of the belt has led the piece which was pressed in the previous cycle out of the effective area of the hammers.

The known device shows some deficiencies which are caused by the method which is used.

The reason for the - in practice -- unsatisfactory results lies in that the buildup of pressure occurs in a relatively short time up to a maximum pressure which is only effective for a short while.which prevents a complete flowing off of the flesh. In order to increase the durability of the belt, additionally an adjustment is carried out which only creates a moderate final pressure and further worsens the yield. The mentioned deficiencies are also responsible for the unsatisfactory quality of the forcemeat (farce) manufactured by the known device. The toughness of the fish flesh has the effect that the flowing off of the flesh only occurs very slowiy which results in the fish flesh being put under increased shear stress.This brings about a destruction of the fibre structure so that the achieved forcemeat tends to jelly. Further disadvantages based on the device lie in the difficulty of vibration damping and limiting the noise level as well as in the fact that the separation of the flesh of warm-blooded animals is not possible.

It is therefore an object of the invention to provide for a press separating method whose use gives-an essentially improved yield with extreme conservation of the fibre structure of the flesh also in the processing of flesh of warm-blooded animals. Further an apparatus for carrying out this method is proposed which can be manufactured with little effort, has a long life and emits minimal noise.

This object is achieved according to the invention by passing the mixture to be press separated through a pressure zone formed by pressing an endlessly running highly flexible pressure belt against the periphery of a perforated drum and by subjecting the material to be separated to an irregularly increasing pressure.

The advantages achieved by this method lie especially in that flesh treated in this way is carefully separated from the parts of firmer consistency, the irregular increase of pressure preventing the possible formation of balls of solid matter obstructing the flow-off of the flesh through the holes in the perforated drum so that a higher yield is guaranteed.

The apparatus which is particularly suitable for carrying out the method according to the invention comprises at least one driven pressure roller pressing an endlessly running highly flexible pressure belt against the periphery of a perforated drum to form a pressure zone within which the separation is formed, wherein the pressure belt has studs of triangular or trapezoidal cross section in the manner of a toothed belt on its inner surface turned away from the perforated drum. In this way a pressure belt of continually varying strength enters the pressure zone, the pressure belt producing a correspondingly irregularly increasing pressure in the pressure zone.

In order to achieve a positive drive of the pressure belt by positive engagement with the pressure roller, the latter can be provided at its periphery with grooves corresponding to the cross section of the studs, the pitch of the grooves corresponding to that of the studs.

If the dimensioning of the grooves of the pressure roller is such that e.g. the width of the studs and/or their height is smaller than the width of the grooves resp. their depth, the characteristic of the buildup of pressure in the pressure zone can be influenced since the grooves can only partially be filled by the studs.

The tendency of the flowable parts of the material to be separated to flow off sideways through the gap between the perforated drum and the pressure belt which exists as a result of the pressure in the pressure zone can be defeated in that the pressure belt is provided with a rotating marginal bead in the region of the edges of its working surface facing the perforated drum, this marginal bead having an almost vertical shoulder facing the longitudinal centre of the pressure belt.

The perforated drum may at the same time be provided with corresponding track grooves which receive the marginal beads of the pressure belt.

In order to reach a good self-cleaning and thereby prevent the material to be separated from sticking in this area, the marginal beads can be designed as declining outwardly from the shoulders, and, therein, e.g. having triangular cross section with a corresponding arrangement of the track grooves in the perforated drum. This effect can be increased further if the perforated drum is provided with holes in the region of the shoulders of the marginal beads.

In order to increase the tensile strength of the pressure belt and thus the pitch accuracy of the track grooves the pressure belt can be armoured with endless or quasi endless e.g. helically wound traction members which touch the bottom of the groove between each two studs and which are arranged adjacent over the whole width of the pressure belt. At the same time the specific compression can be reduced in that the traction members are made of strip steel, the distance between each two neighbouring traction members being greater than their width.

The effect of an increase in tensile strength can also -- however to a smaller degree - be achieved in that the pressure belt comprises at least two closely connected layers of the same material of different Shore hardness, the harder adjustment resp. layer forming the area of the studs.

An example of a device for carrying out the method according to the invention is illustrated schematically in the accompanying drawings, in which: Figure í is a general view of the device by way of a longitudinal cross section; Figure 2 shows an enlarged detailed representation of the pressure zone; Figure 3 shows a pressure-travel diagram of the pressure zone; and, Figure 4 shows a partial cross section through the pressure zone along a generating line of the perforated drum.

A perforated drum 1 driven in a suitable manner is mounted in a not illustrated frame of a separating machine whose casing 2 has a plurality of holes or passages 3. An endless pressure belt 4 made of an elastomer or rubber passes around part of the periphery of the perforated drum 1 and deflects about three deflection pulleys of which one lies closely to the perforated drum 1 and is designed as a pressure roller 5 driven at nearly the speed of the perforated drum 1. The distance between the pressure roller 5 and the perforated drum 1 is adjustable. To this end the pressure roller 5 is arranged rotatabiy around an eccentrically mounted shaft 6. The pressure roller 5 is provided on its circumference with grooves 7 of triangular or trapezoidal cross section extending along generating lines.Corresponding studs 9 of corresponding cross section formed on an inner surface 8 of the pressure belt 4 turned away from the perforated drum 1 engage the grooves 7. The pressure belt 4 is roughened on its working surface 10 facing the working surface e.g. by a knurl-profile contour 11 which is sealed off to the margins by means of marginal beads 13 running parallel to the edges 12 over the whole length.

The beads preferably have triangular cross section and are provided with a vertical shoulder 1 4 facing the longitudinal centre of the pressure belt 4.

Endless or quasi endless traction members 17 which touch the bottom of a groove 1 6 to be found between each two studs 9 are enclosed in the cross section of the pressure belt 4 and extend over the whole length. The traction members 1 7 are designed preferably as belts of synthetic material or metal and can be arranged either parailelly adjacent in the running direction or helically wound so that except for the gaps between them they cover almost the whole width of the pressure belt. The traction members 1 7 are closely connected to the material around them and arranged adjacent to each other in such a way that they do not touch.

According to the schematically produced pressure-travel diagram of Figure 3 when a stud 9 runs onto the pressure roller 5 adjusted in its pressure position to the perforated drum 1 there occurs an increased pressure of the pressure belt 4 against the perforated drum 1 which will be excessive when the following groove 1 6 has reached the region of the pressure zone.

Immediately before the change from first to second state, however, a zone of the pressure belt resulting from the width of the studs 9 which is smaller than that of the groove 7 of the pressure roller 5 arrives in the pressure zone and is not supported by the pressure roller 5. The pressure of the pressure belt 4 on the perforated drum 1 is therefore smaller in this area. This effect can be increased if the height of the studs 9 is smaller than the depth of the grooves 7 so that the back surfaces of the studs 9 are only supported by the pressure roller 5 when the pressure belt 4 is deformed more strongly.

Claims

1. A method for separating closely attached firm and flowable constituents of a mixture, especially the fat and protein parts of the flesh of warm-blooded animals or of fish from inedible parts such as sinews, skin and bones by passing the mixture through a pressure zone formed by pressing an endlessly running highly flexible pressure belt against the periphery of a perforated drum, wherein the material to be separated is subjected to irregularly increasing pressure.

2. An apparatus for separating closely attached firm and flowable parts of a mixture, especially the fat and protein parts of the flesh of warm-blooded animals or of fish from inedible parts such as sinews, skin and bones, the apparatus comprising at least one driven pressure roller pressing an endlessly running highly flexible pressure belt against the periphery of a perforated drum to form a pressure zone within which the separation is performed, wherein the pressure belt has studs of triangular or trapezoid cross section in the manner of a toothed belt on its inner surface turned away from the perforated drum.

3. An apparatus according to claim 2, wherein the pressure roller is provided along its periphery with grooves corresponding to the cross sectional form of the studs, the pitch of the grooves corresponding to that of the studs.

4. An apparatus according to claim 3, wherein the width of the studs is smaller than that of the grooves.

5. An apparatus according to any one of claims 2 to 4, wherein the height of the studs is smaller than the depth of the grooves.

6. An apparatus according to any one of claims 2 to 5, wherein the pressure belt is provided in the area of the margins of its working area facing the perforated drum with a running marginal bead which has an essentially vertical shoulder facing the longitudinal centre of the pressure belt.

7. An apparatus according to claim 6, wherein the perforated drum is provided with track grooves rotating in its marginal zones and receiving the marginal beads of the pressure belt.

8. An apparatus according to claim 6 or 7, wherein the marginal beads decline outwardly from the shoulders.

9. An apparatus according to any one of claims 6 to 8, wherein the perforated drum is provided with holes in the area of the shoulders of the marginal beads.

10. An apparatus according to any one of claims 2, 4, 5, 6 and 8, wherein the pressure belt is armoured with endless or quasi endless traction members which touch the bottom of the groove between each two studs and which are arranged adjacent to each other over the whole width of the pressure belt.

11. An apparatus according to claim 10, wherein the traction members are made of strip steel, the distance between each two adjacent traction members being greater than their width.

12. An apparatus according to any one of claims 2 to 11, wherein the pressure belt comprises at least two closely joined layers of the same material of different Shore hardness, the harder layer forming the area of the studs.

13. A method for press separating foodstuffs substantially as specifically described by way of example with reference to the accompanying drawings.

14. An apparatus for press-separating foodstuffs substantially as specifically described by way of example with reference to the accompanying drawings.