WO1999007228A1

WO1999007228A1 - A method in mechanical treatment of fish or meat fillets or pieces, respectively, and arrangements in a machine for such processing

Info

Publication number: WO1999007228A1
Application number: PCT/NO1998/000235
Authority: WO
Inventors: Ragnar Eide; Oddmund Haugland
Original assignee: Trio Industrier AS
Current assignee: Trio Industrier AS
Priority date: 1997-08-12
Filing date: 1998-08-10
Publication date: 1999-02-18
Anticipated expiration: 2000-02-12
Also published as: NO306143B1; NO973716L; NO973716D0; AU8564798A

Abstract

An account has been given for a method and a machine for use in or relating to the treatment/processing of fish fillets/pieces of meat, where the work piece from a supply conveyor (12) is delivered to a rotary freezing drum (14) and, during the processing thereof, is kept firmly to the circumferential face thereof through freezing. One or more processing tools may be placed along the periphery of the freezing drum, immediately outside the same, including a cutoff knife (20) constituting the only or last processing tool. According to the invention, the supply conveyor's (12) downstream delivery end (12'') for the respective work piece is positioned within an upper area of the 360° rotational path of the freezing drum (14), so that the transfer of the work piece takes place through the force of gravity, simultaneously as ample space is created between this delivery place and the cutoff knife (20) for possibly further, preferably non-withdrawable, but possibly adjustable processing tools, so that the work piece can be completely processed, inclusive cut loose in processed condition from the freezing drum (14), in the course of less than one drum rotation.

Description

A METHOD IN MECHANICAL TREATMENT OF FISH OR MEAT FILLETS OR PIECES, RESPECTIVELY, AND ARRANGEMENTS IN A MACHINE FOR SUCH PROCESSING

The invention relates to a method in mechanical treatment of work pieces in the form of fish fillets/ meat pieces or the like, where the work pieces by means of a supply conveyor are brought into contact with a rotary freezing drum, known per se, having a substantially horizontal rotational axis and, on the circumferential face thereof, the work piece is firmly frozen in order to, thereupon, be kept in position during the subsequent processing comprising that it at least is cut off from the freezing drum (for fish fillets in connection with a skinning/skin removal operation) by means of a cutoff knife, whereupon the layer of the work piece frozen firmly to the drum's circumferential face (the fish skin of fish fillet) is removed from the drum's circumferential face in a subsequent operation, preferably a scraping operation.

Likewise, the invention relates to arrangements in a machine for processing work pieces in the form of fish fillets/meat pieces and the like, comprising an upstream supply conveyor mounted on a machine frame and adapted to be capable of bringing the work pieces in contact with a downstream freezing drum, known per se, rotatably supported on the machine frame about a substantially horizontal rotational axis, wherein a work piece delivered to the freezing drum freezes firmly to the circumferential face thereof, and wherein, at the periphery of the freezing drum is disposed a cutoff knife, e.g. in the form of a movable knife band, the operable cutting edge thereof being spaced from the freezing drum circumference, situated at a short distance therefrom, said cutoff knife being adapted to cut the respective work piece off from the freezing drum, e.g. in connection with a skinning operation (for fish fillets) , and wherein the downstream cutoff knife may be assigned scraping means for scraping off more or less firmly frozen, remaining fish skin, meat or frozen liquid, respectively.

Said movable band knife is a well known component in skinning machines of the general kind concerned, wherein the cutting edge of the band knife device is spaced shortly from the freezing drum circumferential face. Besides for the purpose of skinning fish fillets, such a knife band may likewise be used for the purpose of cutting up a piece of meat, and the slight spacing of the cutting edge from the drum circumferential face secures that only quite unessential amounts of meat have to be scraped off from the freezing face of the drum.

A processing machine having a freezing drum of the kind defined is shown and described in Norwegian Laying-out publication No. 178,781, constituting only one example of a fish fillet cutting machine in connection with skinning (skin removal) , in association with which the present invention could be used advantageously. Thus, flesh of fish and other flesh in the form of fillets or fillet-like pieces is subjected to a mechanical cutting treatment which, in addition to a finishing cutting off operation (skinning in connection with the partition of fish fillet) , can take place parallel with the main faces (top and bottom faces) of the fillet/piece, perpendicularly to these faces, etc. The result may be very thin fish fillet slices, e.g. for salting and smoking in this form; cutting of meat into strips, cubes, etc.

For the advantageous utilization of the present invention, it is a supposition that the mechanical treatment of the piece of meat/fish fillet, etc. comprises delivery of the work piece onto a rotary freezing drum by means of a conveyor, firmly freezing the work piece to the rotary freezing drum, and wherein the work piece at least is subjected to being cut off from the freezing drum. For processing fish fillets, the method then exclusively consists in skinning (skin removal) , and the machine is a skinning machine. However, the work piece may, within the scope of the invention, in addition to the cutting off from the freezing drum, be subjected to at least one further working operation, usually one or more cutting operations, by means of working means disposed at the freezing drum circumference within an area of the rotational path of the freezing drum situated between the delivery place of the work piece and the place of the cutting device (the driven endless band knife) effecting the finishing cutting off operation.

According to known technique, e.g. Norwegian Laying-out publication No. 178,781, work pieces of flesh of fish or other flesh or meat are passed, lying on a conveyor, e.g. in the form of a conveying belt, in beneath a freezing drum onto which they successively freeze firmly as the opposing face (e.g. the skin face of fish fillet) comes into contact with the circumferential face of the freezing drum. The freezing drum rotating synchronously with said supply conveyor for work pieces, lifts the work piece up from the conveyor as a result of the freezing action, and tools placed at the periphery of the drum may work the work piece as the drum is rotated. When the work piece is worked and finished and cut off by means of the knife band, the remaining, firmly frozen layer of meat is loosened from the freezing drum through a scraping effect in the boundary layer between freezing drum circumferential face and inner meat/skin face.

The delivery of the work pieces to the freezing drum from a lower position during lifting involves various disadvantages according to known technique. First, this upwardly transfer makes it very difficult to cause the fillet skin face/the meat piece face to spread evenly and bear tightly on the circumferential face of the freezing drum, and this may easily result in that e.g. skin portions or other waste that should have been pressed into contact with said circumferential face, now project outside this face and, thus, accompany the processed work piece out of the machine.

Another disadvantage is the orientation of the fish fillets/meat pieces during the forward transport toward the freezing drum. This applies especially to fish fillets which must be placed with the skin side facing upwardly. The opposite side, the ''flesh side¹¹, becomes then resting against the conveyor which, moreover, extends in the longitudinal direction of the machine. ''The flesh side''.is more sensitive than the skin side to the influences of bacteria in meat remnants on the conveyor.

Primarily, the object of the invention has been to offer favourable conditions for an advantageous transfer of the work pieces onto the circumference face of the freezing drum from an upstream supply conveyor. In accordance with the invention, this has been achieved in that one proceeds according to the specifically defined delivery step as set forth in the characterizing clause of claim 1.

According to the invention, a method of the kind defined introductorily is characterized in that a respective work piece in the form of a fish fillet, a piece of meat and the like, by means of said supply conveyor, is delivered onto the rotary freezing drum in an upper area of the rotational path thereof. Similarly, the machine for carrying out this method is characterized in that said supply conveyor for work pieces, e.g. in the form of a driven, endless conveying band having a downstream delivery end situated in the upper area of the rotational path of the freezing drum, and scraping means for frost and firmly frozen waste may be disposed downstream the cutoff knife. Skinning machines have been known for 40-50 years. The supply conveyor for unskinned fillets has in all that time had a course situated below the lowermost area of the freezing drum's rotational path.

According to the invention and for the very first time in connection with such processing machines, the weight of the work piece has been utilized in order to obtain an advantageous, tight-fitting rest between fish skin (or meat face) and circumferential face, so that the contact face becomes coherent. According to the invention, e.g. fish fillets with skin are conveyed to the freezing drum, skin side facing down and lying on the conveyor; an orientation of the work piece that is advantageous due to the bacterium attack from meat remnants on the conveyor face. For the last- mentioned object, it is likewise an advantage that the delivery end of supply conveyor is terminated upstream the location for the rotational axis of the freezing drum. For processed work pieces, a special outlet conveyor can be disposed. Two conveyors are considered to be far more advantageous than one through-going conveyor (known technique) in respect of the spreading of bacteria, i.e. that the tendency for bacterium spreading is much less with two individual conveyors than with one conveyor.

According to known technique, fish fillets are orientated on said supply conveyor with the skin facing upwardly, so that it is the skin that is frozen firmly to the freezing drum where the conveyor passes in beneath the drum (see Norwegian Laying-out publication No. 178,781). Treating fish fillet having skin thereon, the removal of the skin in a finishing cutting operation is normally a part of the mechanical treatment of the work pieces. The cutting edge of the knife band which, usually, is adjustable in relation to the freezing drum circumference, is spaced at a small distance therefrom. As the drum rotates and the fillet frozen thereto through the skin or the remaining fillet portion, respectively, passes the knife band, the fillet is cut off from the adhering skin. Thereupon, the skin is scraped off from the drum as it with the skin adhering to the drum circumference passes a scraping means.

In order to utilize the work piece as good as possible, it is desirable to be able to adjust the knife band so close as possible to the drum circumference face, in order to, generally, reduce the amount of scraped off waste and, upon the processing of fish fillets, the cutting edge of the knife band must not be situated so close to the drum circumference face that it can cut into the fish skin. It is, therefore, important that the entire external fish skin face is brought and kept into contact with the freezing drum's circumferential face. In order to obtain this in previously known and conventional processing machines for e.g. fillets, it was, at the underlying delivery place in relation to the freezing drum, necessary to let the conveyor press the work piece evenly up towards the drum circumference face. In known processing machines having a freezing drum, conveyors consisting of a plurality of parallel strings have, advantageously, replaced conveying bands.

In known processing machines for work pieces of the kind concerned, the positioning of the knife band in combination with the delivery place for the work pieces in an underlying area of the freezing drum's rotational path represent considerable disadvantages besides the already mentioned ones. All of these are results of the far too short rotational path stretch (30-40°) thus originating between the delivery place for the fillet and the knife band following the former immediately in the rotational direction of the freezing drum, for cutting off the fillet, the skin thereof scarcely having reached to be properly frozen to the drum's circumferential face.

In a machine for a more advanced treatment of fillets/ pieces of flesh of fish and other flesh or meat, the terminating cut off tool, the knife band, constitute the last one of two or more processing tools.

In known technique it may, in addition to the skinning knife, be disposed e.g. a portioning tool (for dividing fillet into portion pieces) or a tool for making strips (for dividing meat into strips, cubes, etc.). Due to the lack of space along the rotational path of the freezing drum between the delivery place and the cutoff knife's attacking edge, as measured along said rotational path in the freezing drum's rotational direction counterclockwise, the portioning tool must be positioned downstream the cutoff knife band, and the fillet must follow the freezing drum more than one rotation (namely twice past the cutoff knife band) , and it will likewise have to, during the first rotation thereof, pass a scraping tool which, together with the cutoff knife band, must be withdrawable and, thus, made inoperative in relation to the fillet during the first rotation thereof on the freezing drum and processing by means of said portioning tool and/or other tool(s). As soon as the ''portioned'' fillet has passed the cutoff knife band and the freezing drum starts its second rotation in order to be brought into contact with the scraping tool, the portioning tool must be withdrawn from the drum's circumferential face. During these movements to and fro it is more difficult to establish and maintain precision distances between cutting edge and circumferential face.

Such a solution is complex and expensive, and it is clear that the repeated withdrawals and forward movements of the processing tools, as well as the fact that the fillet has to accompany the freezing drum around more than one rotation, will reduce the capacity considerably. According to the present invention, one has therefore also aimed at remedying the disadvantages, deficiencies and restrictions of use pointed out. However, for the time being, this is considered to constitute subordinate objects, unless it is achieved simultaneously in connection with the already defined solutions, wherein the special delivery of the work pieces from above-downwardly from the supply conveyor to the freezing drum constitutes the essence of the invention.

The firmly frozen fish fillet in the upper rotational path area will, thus, have e.g. 90° arced stretch of this rotational path for the freezing drum to run through before it arrives at the cutoff knife, and along this 90° rotational path arc, further processing tools, e.g. knives or cutting devices, can be distributed and will find space, one after the other, so that the cutoff knife becomes the last processing tool when the freezing drum rotates only one time

360°. After the cutoff knife, scraping means will follow.

As mentioned, the work piece at the upper delivery place in relation to the below rotating freezing drum where it shall freeze firmly, will move to rest against the drum through gravity. In order to possibly achieve an even better contact between the work piece, e,g, the fish fillet at the skin side, and the drum, it might, at a processing machine of the kind concerned, in accordance with the invention, be disposed a pressing device acting from above-downwardly and operable in the delivery area of the work piece. The pressing device may have the form of a conveyor, possibly built up of parallel strings which are tangent to or substantially tangent to the freezing drum's circumference at a circumferential face portion of the rotating freezing drum passing an uppermost point at any time.

A non-restricting exemplary embodiment is explained in the following, reference being made to the accompanying greatly simplified and diagrammatic drawing figure showing a side elevational view of a machine for carrying out the method according to the invention, wherein also a special arrangement in the machine constitutes subject matter of the present invention.

From the left hand side of a machine frame 10 extends a supply conveyor 12 for work pieces (not shown) , e.g. in the form of fish fillet with skin, the flesh side facing upwardly, or in the form of a corresponding piece of meat.

The supply conveyor 12 for the work pieces has an upper operative part 12' moving from left to right. According to the present invention, the delivery end 12'' of the conveyor

12 is positioned in the upper area of the 360° rotational path for a freezing drum 14 rotatably mounted on the machine frame 10 and of well known structure and function. The substantially horizontal rotational axis of the freezing drum 14 is denoted at 14 ' . The freezing drum 14 is rotated from a motor 16 through a transmission 18. The rotational direction is clockwise (contrary to the counterclockwise rotation in known machines where the work pieces are delivered to the freezing drum in a lower area of said rotational path) . It is the movement direction of the work pieces at the moment of delivery that decides the rotational direction of the freezing drum 14.

Because the work piece is delivered to the freezing drum in the upper rotational path area thereof in accordance with the present invention, the work piece will move to rest tightly and evenly against the freezing drum's circumferential face through gravity and freeze firmly to the drum across a relatively smooth face layer (e.g. the fish skin) so that the firmly frozen fish skin will have as little as possible extent (thickness) in the radial direction of the freezing drum. A driven endless band knife is diagrammatically indicated at 20 and serves as cutoff knife for fish fillet/piece of meat in the last processing operation. The cutting edge thereof which, for the removal of the cut off fillet/meat piece during the cutting loose thereof from firmly frozen fish skin/meat layer, should take place by means of gravity, is placed at a lower level than the rotational axis 14* of the freezing drum. The cutoff knife 20 is set and adjusted for cutting off minimum waste material, as this is possible because of the tight and even boundary layer/face between the freezing layer of the work piece and the circumferential face of the freezing drum.

In order to improve the tight, even rest between the face of the work piece and the opposing face of the freezing drum's circumference in a brief freezing period, a down-pressing device 22 may be disposed above the supply conveyor's delivery end 10' '. Said device 22 may have the form of a conveyor of band or parallel strings in touching contact with the circumferential face of the freezing drum 14. This pressing conveyor 22 may, advantageously, slope slightly in the longitudinal direction of the machine and covers the freezing drum's upper rotational path area on both sides of the vertical symmetry plane of the drum. 24 denotes a skin scraping means, 26 denoting a frost scraping means.

Processing tools other than the cutoff knife 20 are not shown, but there is ample space for stationary, e.g. non- withdrawable tools in the form of knives and cutting means between the upper rotational path area of the freezing drum 14 (e.g. the zone covered by the down pressing conveyor 22) and the cutting edge of the cutoff knife 20, corresponding to an arc along the circumference of the freezing drum 14 of e.g. 80° (about 30° in known technique) . A so elongated stretch from the delivery place of the work piece to the operative cutting edge of the cutoff knife 20 will allow stationary, preferably non-withdrawable mounting of tools for those processing operations which are actual in connection with work pieces of the kind concerned and with association to a rotary freezing drum assigned a cutoff knife 20 effecting the last processing step. Following scraping means for skin and frost are here not considered as processing tools, because they do not process the work pieces, but rather the more or less firmly frozen waste products thereof.

An outlet conveyor is denoted at the reference numeral 28.

Claims

C l a i m s

1. A method in mechanical treatment of work pieces in the form of fish fillets/pieces of meat and the like, wherein the work pieces by means of a supply conveyor (12) are brought into contact with a rotary freezing drum (14) known per se and having a substantially horizontal rotational axis (14'), on the circumferential face thereof the work piece freezes firmly and is thereupon kept in position during the subsequent processing, which comprises at least a cutting off thereof from the freezing drum (14) (for fish fillets in connection with a skinning operation) by means of a cutoff knife (20) , whereupon the work piece layer firmly frozen to the drum circumference face (fish fillet: the fish skin) is removed from the drum's circumferential face in a subsequent operation, preferably a scraping operation, c h a r a c t e r i z e d i n that the respective work piece in the form of a fish fillet, a piece of meat and the like, by means of said supply conveyor, (12) is delivered to the rotary freezing drum (14) in an upper area of the rotational path thereof.

2. A method as set forth in claim 1, c h a r a c t e r i z e d i n that the work piece during the delivery from the supply conveyor (12) to the freezing drum's circumferential face in the upper area of the rotational path, in addition to the gravity effect, wherein the work piece's own weight contributes to substantially tight positioning thereof on the circumferential face of the freezing drum (14) , is subjected to a pressing action substantially directed downwardly from above in order to, if necessary, to press the downward facing face of the work piece further evenly into contact with said circumferential face, so that the firmly frozen face layer, e.g. the skin on a fish fillet, thereafter projects minimum outside the circumferential face in the radial direction of the freezing drum (14) .

3. Arrangements in a machine for treating/processing work pieces in the form of fish fillets/pieces of meat and the like, comprising an upstream supply conveyor (12) mounted on a machine frame (10) and adapted to bring the work pieces into contact with a downstream freezing drum (14 known per se and rotatably mounted on the machine frame (10) about a substantially horizontal rotational axis (14'), where a work piece delivered to the freezing drum (14) is frozen firmly to the circumferential face thereof, and where, at the periphery of the freezing drum (14) , a cutoff knife (20) is disposed, e.g. in the form of a movable knife band, the operative cutting edge thereof being spaced shortly from the freezing drum circumference, said cutoff knife (20) being adapted to cut the respective work piece off from the freezing drum (14), e.g. in connection with a skinning operation (fish fillets) , and where, downstream the cutoff knife (20) , scraping means (24, 26) might be disposed, for scraping away more or less firmly frozen fish skin remnants/remnants of meat or frozen liquid, respectively, c h a r a c t e r i z e d i n that said supply conveyor (12) for work pieces, e.g. in the form of a driven, endless conveying band, has a downstream delivery end (12'') situated in the upper area of the rotational path of the rotary freezing drum (14), and that scraping means (24, 26) for frost and firmly frozen waste may be disposed downstream the cutoff knife (20) .

4. Arrangements as set forth in claim 3 , c h a r a c t e r i z e d i n that the supply conveyor's operative, upper band or string conveyor part (12') extends substantially horizontally or slopes slightly upwardly from the upstream end to the downstream delivery end (12'*), and that a turning roller/ member at the delivery end (12'') has the smallest possible diameter.

5. Arrangements as set forth in claim 3 or 4, c h a r a c t e r i z e d i n that the delivery end (12*') of the supply conveyor (12) is positioned within 60° of the uppermost arc of the rotational path of the freezing drum (14) having a horizontal axis (14').

6. Arrangements as set forth in claim 5, c h a r a c t e r i z e d i n that the arc-shaped stretch of said rotational path between the delivery end (12'') of the supply conveyor (12) and said cutoff knife's (20) operative cutting edge amounts to between 70 and 95°.

7. Arrangements as set forth in any one of the claims 3 - 6, c h a r a c t e r i z e d i n that within said delivery area for the work piece from the supply conveyor's (12) delivery end (12'') to the circumferential face of the freezing drum (14), above said delivery end (12*'), a pressing means has been disposed, for pressing the delivered work piece downward in order to establish and maintain tight and evenly distributed facial contact with the cold circumferential face of the freezing drum (14) .

8. Arrangements as set forth in claim 7, c h a r a c t e r i z e d i n that the pressing means has the form of a conveyor (22) having an endless conveying band, possibly formed by parallel strings extending in the conveying direction, substantially resting against the circumferential face of the freezing drum (14) in the uppermost arc-shaped area of the rotational path thereof.

9. Arrangements as set forth in claim 8, c h a r a c t e r i z e d i n that the pressing conveyor (22) is pivotally disposed at its upstream end about a substantially horizontal axis and, in other respects, has a cantilever course, having an outer, free downstream end.

10. Arrangements as set forth in claim 3, c h a r a c t e r i z e d i n that the upper, operative part (12') of the supply conveyor (12) has a course in the longitudinal direction of the machine which corresponds to the feeding direction of the work piece, the latter direction extending approximately as a tangent to the circumferential face of the freezing drum (14) .

11. Arrangement as set forth in claim 3, c h a r a c t e r i z e d b y an outlet conveyor (28) extending, preferably slopingly upwardly, from an upstream place at the downstream area for the rotational path of the freezing drum (14) , and out from the machine, so that the work pieces in this machine are assigned two conveyors extending approximately in the continuation of each other, a supply conveyor (12) for untreated work pieces and an outlet conveyor (28) for treated work pieces.