GB2484572A

GB2484572A - Liquid bath polygonal drum

Info

Publication number: GB2484572A
Application number: GB1116460.5A
Authority: GB
Inventors: Stephen Manson; Ian Jones; David Alan Norris
Original assignee: DC Norris and Co Engineering Ltd
Current assignee: DC Norris and Co Engineering Ltd
Priority date: 2010-10-13
Filing date: 2011-09-22
Publication date: 2012-04-18
Also published as: GB201116460D0; GB201108379D0

Abstract

Apparatus to heat, reheat or chill foodstuffs having a casing for retaining a bath of liquid and heating elements to heat the liquid bath. The foodstuff is introduced into the drum by way of an access opening. The drum 16 (Fig 1) has a polygonal cross section and is supported within the casing for rotation about a horizontal axis; the peripheral wall of the drum is formed of a plurality of planar sides , each disposed at an angle to sides adjacent to it. A plurality of the planar sides of the drum are formed from one metallic sheet. The peripheral wall of the drum is provided with means to allow liquid to pass therethrough into the interior of the drum. The access opening when the apparatus is in operation is provided with a protrusion 30 for promoting tumbling of the foodstuffs. The access opening may comprise a flap 26 which may be hingedly connected to the drum. The drum may be hexagonal in cross section. Releasable fastenings 28 may be used to hold the flap in a closed position.

Description

FOOD PROCESSING APPARATUS

Industrially pre-cooked food products may be packed in plastics bags immediately after cooking. In preparation for storage or transportation, the bags, which may each weigh seven kilograms for example, may be chilled to a temperature of or about 4 degrees Celsius.

Our patent specifications GB-2 419 396 and GB-2 419 397 relate to a chiller which incorporates a casing for containing a water bath. A drum having a perforated peripheral wall is supported within the casing for rotation about a slightly inclined axis. At the commencement of a chilling operation bags of food product are loaded into the drum and the water bath maintained at a temperature of substantially zero degrees Celsius while the drum is driven in rotation. The bags tumble in the water which circulates through the drum. Chillers made to this design have proved to be very effective in use, but are relatively large in size.

There is, consequently, a need for a chiller of more compact construction.

Following storage or transportation, the temperature of the bags generally needs to be raised to ambient if further processing is to take place. As yet, there is no wholly satisfactory apparatus available for this purpose, and it would be beneficial for an apparatus capable of reheating the bags to be made available to the food processing industry. The industry would also benefit from an apparatus which is capable of chilling or reheating such bags, depending upon the need at hand. Apparatus for heating bags of food product to a temperature above ambient would also bc of use in connection with in-bag cooking.

It is known from US 2004/022 1725 Al (Wong) to cook food products within a perforated drum which rotates about a horizontal axis. The bottom of the drum is immersed in a hot cooking liquid which flows into the drum through perforations in the drum wall, so that the food products S tumble into and out of the cooking liquid as the drum rotates.

In all of the above-mentioned instances the perforated drum is of a substantially circular éross-section, which presents manufacturing difficulties. In the case of US 2004/0221725 Al, these difficulties are exacerbated by the fact that the peripheral surface of the drum has to be formed with ridges and channels which extend parallel to the axis of the drum, such ridges being intended alternately to trap and release food products as the drum rotates, with the intention of promoting their agitation and cooking. The metallic sheet used to form the drum has, therefore, to be stamped into a "wavy" shape before being bent into a cylinder of substantially circular cross-section.

Having regard to the foregoing there is consequently a need for apparatus for chilling, heating or re-heating bags of food product which is less djfflcult to manufacture, and it is an object of this invention to provide apparatus which overcomes the above-mentioned problems.

According to the invention an improved food processing apparatus comprises a casing for retaining a liquid bath, means for heating and/or cooling the liquid thereof depending upon the purpose of the apparatus, a drum for containing bags to be heated or chilled and having a peripheral wall adapted to allow liquid to pass therethrough, the drum being supported at least partially within the casing for rotation about an axis which is horizontal or inclined to the horizontal, and means for driving the drum in rotation, the drum being of polygonal cross-section so that its peripheral wall is characterised by a multiplicity of planar sides, each of / which is disposed at an angle to the sides adjacent to it and all but one of * which sides is constituted by a respective portion of a length of metallic sheet bent to shape, the remaining side incorporating a frame defining an access opening into the drum and provided with a closure member for the access opening.

The closure member may conveniently take the form of a flap which covers the access opening in order to close it. However, the closure member may take any convenient form. The closure member is provided ith a protrusion which, when the closure member is in its closed position, projects into the interior of the drum. In the case where the closure member is formed by a flap the protrusion may project through is the access opening as described hereinafter. In an alternative, in which tkie closure member is arranged to fit door-like within the access opening in order to close it, the protrusion would be located within the drum in its entirety. The protrusion may be constructed by pressing it out of the closure member and serves to displace the bags as the drum rotates. 20!

The manufacture of a drum with polygonal sides is much simpler than that associated with a drum which is of substantially circular cross-section as disclosed in the patent specifications referred to above.

Because the drum of the invention has a plurality of straight sides the shaping of the drum is readily carried out using readily availablepress tools, and without the need for special jigs.

Moreover, it is much simpler to provide the closure member with a protrusion which is positioned within the drum when the apparatus is in use, compared to stamping the drum into a "wavy" shape as proposed in Us 2004/0221725 Al.

Preferably the drum is of a regular polygonal cross-section, and in the form of a regular hexagon.

Any one embodiment of apparatus in accordance with the invention may be adapted solely for chilling the contents of the drum, or solely for heating those contents. Alternatively the apparatus may be adapted so as to be capable of performing both functions separately, being provided or associated with both heating means and chilling means.

The closure member may, as mentioned above, take the form of a flap and be hingedly connected to the frame. A releasable fastening, such as a conventional catch or latch may be provided for holding the flap in a closed position so as to prevent bags falling out of the drum into the casing when the drum is in motion. One end of the metallic sheet may be attached to one axially extending side of the frame, extend in a hexagonally shaped arc away therefrom, and be attached to the opposite axially extending side of the frame.

The protrusion is adapted to displace bags being tumbled in the drum during its rotation, thereby promoting chilling, heating or cooking as the case may be. The protrusion may be formed by depressing a central portion of the flap, or may be a separate component attached to the flap.

The drum and casing for containing a liquid bath may be supported within a housing which may be provided with a hinged cover so that the drum may be brought to a halt and the cover and flap raised to enable bags to be introduced into, or removed from, the drum.

Polygonal end-pieces may be fitted to the ends of the drum, and be provided at their centres with bearings for receiving stub shafts supported by the housing or other support structure of the apparatus. An electric motor may be coupled to the drum by way of gearing. In the alternative, the end pieces may be provided with stub shafts received in bearings supported by the housing or a support structure of the apparatus. to

Conveniently the liquid bath consists of water, although other liquids may be used if the apparatus is used to perform a cooking operation.

When the invention is embodied in an apparatus for heating or reheating bags of previously chilled food product, one or more heating elements may be provided and extend into the casing and be arranged at such a height that they lie below the level of the surface of the liquid bath.

Alternatively liquid circulated through the apparatus may be pumped into the apparatus from an external heat exchanger.

When the invention is embodied in a chiller the liquid bath may be chilled by means of a refrigerant using the system disclosed in our above-mentioned patent specifications. Alternatively cooling liquid may be circulated through the apparatus and pumped from an external heat exchanger.

In the drawings:

S

Figure 1 is an isometric view of an embodiment of apparatus in accordance with the invention, Figure 2 is a diagrammatic end view of the apparatus shown in Figure 1, Figure 3 is a side view of the apparatus shown in Figure 2, Figure 4 is an isometric view of an embodiment of the drum forming part of the apparatus shown in the foregoing figures, Figure 5 is a plan view of a length of perforated metallic sheet for use in constructing a drum shown in Figure 4, Figure 6 illustrates the sheet folded into a configuration in readiness for attachment to the frame, and Figure 7 is a plan view of an end piece.

Referring to Figures 1 to 3 of the drawings, apparatus in accordance with the invention comprises art outer housing 2 within which is mounted an open-topped casing 4 adapted to retain a water bath. A tap 6, or other inlet, serves to supply water to the water bath. A drain pipe 8 is connected to the casing 4 and is provided with a valve 10 which may be opened by a lever 11 to drain the water bath.

A drum 16 is supported for rotation within the housing upon bearings 18 and at such a height that its lower part is received within the casing 4.

The water bath is maintained at such a level that the bearings and components of the drive system for the drum are not immersed in the water. The drum is drivable in rotation by an electric motor 15 rotflhti5nally connected to the drum by way of gearing I 5A. The motor, giig and certain other electrical components and circuitry may be housed within an enclosure 14 at the right-hand end of the apparatus as vievedinFigurel.

The dram 16 is of hexagonal cross-section, its peripheral wall having six planar sides, five of which consist of rectangular sheet steel sections 17 with arrays of perforations throughout. The remaining side is formed by a frame 23 which bounds an access opening into the interior of the drum.

The frame is provided with a closure member in the form of a flap 26 movable between a position in which the access opening is closed and a position in which is open. The access opening, being concealed by the flap, is not visible in the drawings.

The drum is constructed in part from a length of stainless steel sheet S which has been cut to the shape depicted in Figure 5 and provided with perforations P throughout. The sheet is dimensioned such that five rectangular sections are defmed by four transversely extending fold lines F together with the endmost transverse edges E of the sheet.

The perforated sheet is initially formed into a structure T having the shape shown in Figure 6 by using a suitable press tool to fold the sheet along each of the fold lines F. Meanwhile a pair of end pieces 27 are cut from stainless steel sheet so as to have the substantially hexagonal shape shown in Figure 7, the edges of which may serve as tabs, including those indicated at 27A, 27B and 27C. The frame 23 and the end pieces 27 are offered up to the structure T, and the tabs 27A folded over and welded or otherwise secured to the edges 23A of the frame. The remaining tabs are folded over and welded or otherwise secured to edge portions of the sheet so as to complete the assembly of the drum. The end pieces are ufficiently rigid as to support the peripheral wall of the drum without it or the endpieces distorting. Formed in the end pieces adjacent the roots of the tabs (other than tab 27A) are slots 27D dimensioned to receive corresponding projections 16A appropriately positioned along the longitudinal sides of the sheet. Welding the tabs to the frame and sheet S may be unnecessary provided that the projections and slots establish sufficiently firm joints between end pieces and sections of the sheet 5, and the frame is similarly held in place.

The perforations with which the sections are pierced (other than that constituted by the frame), enable water to circulate between the water bath within the casing and the interior of the drum. The closure member in the form of rectangular flap 26 is attached by hinges 39 to one axially extending side member of the frame 23 and may be fixed in place to the parallel side member by a latch 28.

The flap 26 has an open position not shown in the drawings in which access to the interior of the drum may be gained by way of the access opening through the frame 23, and a closed position as shown iii which it overlies the access opening and in which it may be secured by the latch 28, components of which are provided on the longer, free edge of the flap and on the adjacent longer edge of frame 23 The flap 26 has a pressed-out protrusion 30 which extends substantially the length of the flap and projects into the drum through the access opening when the flap 26 occupies its closed position. In Figure 3 the protrusion 30 is shown in the position which it occupies when the flap is closed and the drum has been rotated in the clockwise direction by 60 degrees.

A lid 32 is hinged to the outer housing and has an open position as shown in the drawings in which it is tilted to the rear and allows access to be gained to the drum, and in particular to the access opening in the drum.

The lid may be tilted forwardly into a closed position in which it encloses the drum. Five thermostatically controlled electrical heating elements 20 extend into the casing 4 in the region of its base. Of course the apparatus may be provided with more or fewer heating elements.

In operation as a re-heater or a heater for cooking purposes, water is admitted to the casing 4 in a quantity necessary to bring the water bath to a level just below that of the drum axis, or thereabouts, so that the bearings are not immersed in the water. The lid 32 and flap 26 are moved into their open positions and bags of chilled food product introduced into the drum by way of the access opening 25. The flap 26 is moved into its closed position and latched in place, and lid 32 closed to seal the apparatus.

Current is supplied to the heating elements 20 so as to heat the water in the casing. The motor 15 is started and the drum rotated. The bags are subjected to a tumbling action and are heated by contact with the water within the drum. The use of a polygonal drum achieves an improved effect in comparison with a drum of circular cross-section because the profile of the drum tends to lift the bags out of the water and then drop them back into it.. As the protrusion 30 circulates through the water bath, passing through the surface of the water as it does so, it serves to turn the bags over and enhance the tumbling effect and heat transfer. Water flows continuously between the interior and exterior of the drum by way of the perforations.

When the lid 32 is closed it is impossible for the rotating drum to cause water to splash out of the apparatus. The apparatus may be brought to a halt from time to time, the lid 32 and flap 26 opened, and the temperature of a sample bag checked. At the completion of the operating cycle, water may be drained from the drum and casing, the flap and lid opened and the reheated bags removed using a mechanical gripper.

To enable the apparatus to be used as a chiller, either solely as such or alternately as a chiller and heater, the lower part of the casing 4 may be formed on each of its lateral sides and on its underside by a cooling jacket which defines a passageway through which refrigerant, for example ethylene glycol, is passed when the chiller is in use. The refrigerant is supplied to the upper region of the jacket through an inlet (not shown) on one side of the casing, and flows through the jacket to an outlet (also not shown) on the other side of the casing.

A circuit between the outlet and inlet includes a pump for circulating the refrigerant and a heat exchanger for extracting heat from the refrigerant.

A more complete explanation of the cooling system may be found in our patent specifications referred to above. If the apparatus is to be used both as a heater and chiller it is provided with both heaters and a refrigerant system. Operation takes place as described above, but with the bags being chilled or heated as the case may be. I0

As illustrated, all of the sections formed from the metallic sheet are provided with perforations. It falls within the scope of the invention for one or some only of such sections to be perforated.

The drum may have more or fewer sections so that end pieces having the shape of polygons other than hexagons may be employed. It is preferred for the drum to have the shape of a regular polygon, although it may be of irregular polygonal shape It falls within the scope of the invention for the peripheral wall of the drum to be made water permeable in some way other than by punching perforations into it as described above, such as by forming the wall from metal mesh. Liquids other than water, for example brine, may be used to extract heat from the bags, or impart heat to them. Preferably the drum rotates about a horizontal axis, but it falls within the scope of the invention for it to rotate about an inclined axis.

As described above and shown in the drawings, the tabs used to weld the end pieces to the sheet which forms the peripheral wall of the drum are provided on the end pieces. Alternatively the tabs could be provided on the edges of the sheet and frames, and folded over the end pieces.

It may be possible to dispense with welding the folded-over tabs and depend solely upon inter-engagement of the projections with the slots in the end pieces.

Although the apparatus has been described an illustrated to have a closure member in the form of a flap which overlies the frame, so that the protrusion extends through the access opening into the interior of the

II

drum, it will be understood that the closure member may take any convenient form and may seat within the access opening in the nature of a door, such that the protrusion is positioned wholly within the drum when the closure member is in its closed position. Such an arrangement is intended to fall within the scope of the invention. References to the "frame" in the claims which follow are also to be understood in a general sense and to comprehend any arrangement capable of performing the function of the frame explained above, namely providing a connection between the ends E of the length of sheet steel and supporting the closure member. Similarly, although intended for the processing of bags of food product the apparatus disclosed herein may be used in connection with other containers of food product, or other food related articles, and such usage is to be understood to fall within the scope of the invention.

Also within the scope of the invention is an apparatus in which all of the sides of a polygonal drum are formed from a length of metallic sheet and one àf said sides is provided with an access opening therein, and the closure member is mounted on that side. Reinforcement of such a side proiided with an access opening may be necessary depending on the thickness of the sheet.

As shown in Figure 1 in particular the drum projects above the level of the casing 4 which contains the water bath. This facilitates the introduction and removal of the bags to chilled or heated. However, the drum may be housed entirely within the casing.

Claims

CLAIMS1. Food processing apparatus comprising a casing for retaining a liquid bath, means for heatirig and/or cooling the liquid thereof depending upon the intended purpose of the apparatus, a drum for containing bags of food product to be heated or chilled as the case may be, the drum having a peripheral wall adapted at least in part to allow liquid to pass theréthrough, the drum being supported at least partially within the casing fçr rotation about an axis which is horizontal or inclined to the horizontal, and means for driving the drum in rotation, the drum being of polygonal cross-section so that its peripheral wall is characterised by a multiplicity of planar sides, each of which is disposed at an angle to the sides adjacent to it, at least some of said sides being constituted by respective portions of an undivided length of metallic sheet, one of said sides having assoàiated therewith an access opening into the interior of the drum and a clOsure member movable between a first position in which the access * opening it obstructed and a second position in which the access opening is unobstructed, the closure member being provided with a protrusion whièh, when the closure member is in its first position, is located at least partly within the drum so as to be capable of deflecting or otherwise acting on bags within the drum during its rotation.
2. Apparatus as claimed in claim 1, wherein the access opening is provided in a frame.
3. Apparatus as claimed in claim 2, wherein the closure member is formed by a flap which overlies the frame in its first position.

*
4. Apparatus as claimed in any preceding claim, wherein a lid hingedly connected to an outer housing of the apparatus is displaceable to allow access to the drum and to the access opening therein.
5" Apparatus as claimed in any preceding claim, wherein the drum is hexagonal in cross-section.
6. Food processing apparatus comprising:-a) a casing for containing a liquid bath, b) means for heating andlor cooling the liquid of said bath depending upon the purpose of the apparatus, c) a drum disposed at least partially within the casing for rotation about an axis which is horizontal or inclined to the horizontal, d) means for driving the drum in rotation, wherein: e) the drum is of polygonal cross-section such that its peripheral wall is characterised by a multiplicity of contiguous planar and rectangular sides, separated one from another by transversely extending folds, each side being disposed at an angle to the sides next adjacent to it, f) each of all but one of the sides of the drum is constituted by a respective portion of an elongate metallic sheet which is perf&ated or oierwise capable of permitting the passage of liquid therethrough, S g)' a further side of the drum is constituted by a frame bounding an access opening into the drum, one end of the metallic sheet being attached to a first side member of the frame, and the other end of the metallic sheet being attached to a second side member of the frame spaced from the first side member, h) a closure member is provided on the frame and is movable between a first position in which the access opening is obstructed and a second position in which the access opening is unobstructed, releasable fastenings being provided for holding the closure member in its closed position, i) a protrusion is provided on the closure member and is arranged to be located within the interior of the drum when the closure member is in its first position, and j) polygonal end-pieces are fined to the edges of the drum, and supported for rotation.
7. A method of manufacturing apparatus for use in food processing, including constructing a drum by means of the following steps carried out in the order hereunder given or in any other convenient order:- (a) forming multiple perforations in an elongate metallic sheet, (b) folding the sheet along a series of transversely extending foidlines so as to form a drum-like structure conforming to the shape of polygonal end pieces, and so that the periphery of the structure is characterised by a plurality of planar sections, (c) one side of the periphery of said structure being characterised by a gap located between the ends of said sheet, (d) securing a frame in said gap, said frame defining an access opening into the drum, (e) securing the edges of the sheet to said polygonally-shaped end pieces, and (1) wherein before or after said frame is secured in place in the gap it is provided with a closure member movable to open or close the space within said frame, the closure member being provided with a protrusion..
8. Apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.