GB2419396A

GB2419396A - Tumble chillers

Info

Publication number: GB2419396A
Application number: GB0521388A
Authority: GB
Inventors: David Alan Norris
Original assignee: DC Norris and Co Engineering Ltd
Current assignee: DC Norris and Co Engineering Ltd
Priority date: 2004-10-21
Filing date: 2005-10-20
Publication date: 2006-04-26
Anticipated expiration: 2025-10-20
Also published as: GB201017018D0; GB2419397A; GB2419397B; GB2471242B; GB0521389D0; GB2419396B; GB0521388D0; GB2471242A; GB0423420D0

Abstract

A tumble chiller comprises a housing (2, Fig 1) provided with a door (4, Fig 1) which incorporates a chute (6) to allow bags of hot food products to be introduced into the chiller. Located within the housing is a drum (8) having a perforated peripheral wall (10). The drum is partially immersed in a bath of cooling liquid. The drum is supported for rotation at each of its ends by a pair of laterally spaced rollers (12a 12b) which engage the inner sides of cylindrical flanges (14a, 14b fixed to the front and rear ends of the drum (8). The axis of the drum maybe inclined to the horizontal. The drum maybe driven by a sprocket (20) which meshes with a roller chain (22). The bearings of the support and drive arrangements are located above the level of water in the drum. The drum is housed in a trough-like inner casing (28) which is positioned within a trough-like outer casing (26). In use water finds a level determined by a series of four slots (30) positioned on opposite walls of the inner casing (28). The water flows through the perforations (10) in the drum wall and into an inner passageway (44) formed between the drum and the inner casing (28). Scoops (40) cause water to flow through the series of slots (30) into an outer passageway (46) formed between a cooling jacket (32) and the outer casing (26), re-entering the inner passageway (46) through the slots (30) on the opposite side of the drum. The lower part of the inner casing (28) is formed by the cooling jacket (32) through which a coolant, such as ethylene glycol may flow via an inlet duct (54, Fig 3) and an outlet duct (56, Fig 3).

Description

24 1 9396 P26694GB-02

IMPROVEMENTS IN OR RELATING TO CHILLERS

This invention relates to chillers, particularly but not exclusively for bagged food products.

Industrially cooked food products may be packed in plastics bags immediately after cooking. In preparation for storage or transportation, the bags, which may be weigh seven kilogrammes for example, need to be cooled from a temperature of say 85 C to 4 C. A tumble chiller is known for this purpose which includes a drum rotatable within a cylindrical casing. The drum has a perforated circumferential wall so that cooling water supplied to the casing may flow through the drum in which the bags are tumbled during rotation of the drum. A circuit for the cooling water includes a pump, a filter and a heat exchanger in which ethylene glycol may be used to reduce the temperature of the water to slightly above freezing.

The drum is supported by a cantilevered drive shaft which extends from its base through an end wall of the casing, and is coupled to a drive motor. A problem with this arrangement is that the bearings of the drive shaft are below the water level in the drum and its casing. In the event that the seals for the bearings become worn, water may seep into the bearings and corrode them.

In order to overcome this problem the invention provides a chiller for articles, particularly in the form of bagged food products, comprising a casing and a drum supported within the casing for rotation about an axis which is horizontal or inclined to the horizontal, the casing being adapted to contain a bath of cooling liquid for articles deposited within the drum, wherein rotary drive means for the drum is positioned above the axis of the drum and spaced therefrom.

Drive may be transmitted to the drum by a pinion and ring gear mechanism. The pinion may be arranged above the level of the cooling liquid, even though the ring gear is partially immersed in the liquid. However, any corrosion of the ring gear which may take place has no adverse consequences for the proposed chiller, unlike in the case of the conventional chiller in which corrosion of the drive shaft bearings may result in the chiller - 2 having to be shut down.

In the drawings: Figure 1 is an external view of a chiller embodying the invention; Figure 2 is a plan view of the chiller; Figure 3 is a cross section taken on line lll-lil in Figure 4; Figure 4 is a longitudinal section taken on line IV-IV in Figure 2; Figure 5 is a cross section through a fragment of the cooling jacket to an enlarged scale; Figure 6 is a section taken on the line VI-VI in Figure 4; Figure 7 is a perspective view of the support and drive system for the drum, Figure 8 illustrates one side of casings or tanks enclosing the drum.

Referring to the drawings, a tumble chiller has a box-like outer cladding or housing 2 assembled from panels and carried by a support structure or frame. The cladding is provided with a door 4 in its front wall. The door incorporates a chute 6 to allow bags of hot food product to be introduced into the chiller. Following cooling, the door may be opened and the bags removed by hand.

Located within the cladding is a drum 8 having a perforated peripheral wall 10. The drum is partially immersed in a bath of cooling liquid conveniently water or brine referred to herein as "water". Systems are provided for circulating the water, through the drum and driving the drum in rotation, so that the bags tumble in the water and are cooled from, say, 85 C to about 4 C.

In the above respects, the chiller does not differ substantially from the prior art. In accordance with one aspect of the invention, however, the drum is supported for rotation at each of its ends by a pair of laterally spaced, rubber-tyred rollers 12a and 12b which engage the radially inner sides of cylindrical flanges 14a and 14b respectively, fixed to the front and rear ends of the drum at its periphery. Only one roller in each pair is shown in Figure 4, both rollers 12b being shown in Figure 7.

The rollers 12b for supporting the rear end of the drum are mounted on a support plate - 3 16 bolted to the support structure of the chiller in the region of the upper extremity of the drum. It will be noted from Figure 4 that the axis of the drum is inclined to the horizontal at an angle of substantially 10 , sloping down from its forward end so that the axes of the rollers are similarly inclined. The rollers at the front end of the drum will necessarily be positioned higher than those at the rear end.

Unless prevented, the inclination of the drum leads to a tendency for the drum to slide rearwardly and its rear wall to bind against the faces of the rollers 12b. To resist this tendency, a pair of laterally spaced rollers 18 are mounted in brackets on the plate 16 to bear against the end wall of the drum, as shown in Figure 7.

As remarked above, the conventional tumble chiller is supported in a cantilevered fashion on a shaft fast with the centre of its rear end wall. Demounting of the conventional drum for repair necessarily involves extracting the shaft from its bearings and removing the drum from the front of its cladding. With the arrangement provided by the present invention, it is a relatively simple matter to remove the top panel of the cladding and shift one pair of rollers to disengage from their associated flange, and then lift the drum out of its housing. The support plate 16 may be mounted in such a way that it can be removed or displaced for this purpose.

In accordance with another aspect of the invention, drive for the drum is provided by a sprocket 20, the shaft of which is journalled in bearings mounted in the plate 16 midway between the rollers 12b. The sprocket 20 meshes with a conventional roller chain 22 welded or otherwise secured to the flange 14 at the rear of the drum, axially inwardly of the track for the rollers 12b. The use of a sprocket and roller chain system for driving the drum allows of a simple construction with readily available components. The sprocket is driven from an electric motor 24 through a transmission system 25, the motor and transmission system being mounted on the opposite side of the support plate 16, as shown in Figure 7.

A purpose made pinion and internally toothed ring gear arrangement may be used instead of the sprocket and chain, and for present purposes the sprocket and chain arrangement described herein are to be regarded as a pinion and ring gear. As illustrated, the chain is welded to the radially inner side of the flange but it could be - 4 mounted on the radially outer side.

It will be appreciated that at least the bearings of the support and drive arrangements described above are located well above the level of water in the drum so that there is no risk of corrosion of the bearings from direct contact with the water. Preferably, of course, the sprocket 20 and the rollers 12a 12b and 18 are disposed in their entirety above the water level.

A system for extracting heat from the water and maintaining it at a desired low temperature forms the subject matter of co-pending application No. (Serial No. ) and will now be described.

The drum is housed within a trough-like inner casing 28 of U-shaped cross section. A trough-like outer casing 26 of U-shaped cross-section encloses the lower part of the casing 28, the arcuate portions of both casings being concentric. An inner passageway is formed between the drum and inner casing on the one hand, and an outer passageway is formed between the inner and outer casings, on the other. Water is supplied to the chiller by way of a pipe 61 and the level maintained by an overflow 62.

The casing 28 has a series of four slots 30 disposed in a horizontal row in each of its side walls slightly below the level of the overflow. The two rows of slots are arranged at the same level. A horizontal flange 42 extends inwardly from each of the upper edges of the casing 26 and is welded to the inner casing 28. A series of openings 43 is provided in each of the flanges to allow the space between the two casings to be cleaned, for example by hosing water through them.

The lower part of the inner casing 28 is formed by a cooling jacket 32 within which is provided a semi-annular passageway through which a coolant, for example ethylene glycol, may be passed. Coolant is supplied to upper region of the jacket on one side through a Inlet duct 54. The coolant flows through the jacket, following an arcuate path, to an outlet duct 56 arranged to permit the escape of coolant from the upper region of the other side of the jacket. The jacket is of the dimpled type, as depicted in Figure 5, in which the plates making up the inner and outer skins of the jacket are spot-welded together at longitudinal and transverse intervals to form dimples to enhance the cooling effect. A circuit between outlet duct 56 and inlet duct 54 includes a pump for circulating - 5 the coolant and a heat exchanger for extracting heat from the coolant. An inlet 58 allows steam to be injected into the water within the chiller after operation so as to cause the water to boil and promote cleaning. An outlet 60 allows the chiller to be drained.

The peripheral wall of the drum has projections 40 in the nature of scoops formed on its sides which run along the length of the drum. The drum is also provided with internal paddles 41 to promote agitation of the liquid within it.

In use, water is admitted to the system and finds a level determined by the overflow and substantially that of the slots 30. The water fills the drum and the spaces within the outer casing 26. When bags have been placed within the drum the motor is started and rotates the drum to tumble the bags. Water may flow through the perforations in the drum between the drum interior and its exterior. The scoops 40 cause water in the inner passageway 44 formed between the drum and the inner casing to circulate in the clockwise direction as viewed in Figure 6 and to pass through the slots 30 into the outer passageway 46 between the cooling jacket and outer casing, as indicated by the arrow A. In the outer passageway the water follows a path around the underside of the drum, to re-enter the inner passageway through the slots on the opposite side of the drum, as indicated by the arrow B. A continual flow of water therefore takes place through the drum and around both sides of the cooling jacket, thereby enhancing the cooling effect achieved by the coolant, in comparison with an arrangement in which only one side of the jacket is utilised. During operation of the chiller, heat is extracted from the bagged food product by the water, and then extracted from the water by the ethyl glycol.

Because the cooling jacket has a substantial area, embracing over one half of the surface area of the drum, and the inner and outer passageways for the flow of water are substantially co-extensive with the jacket, there is no risk of flow becoming blocked following breakage of a bag or localised freezing. The cooling effect provided by the jacket is capable of maintaining the water at a low temperature consistent with reducing the temperatures of the bags to the desired level. In the event that the water becomes polluted it is a simple matter to drain the chiller, so that no filter is needed.

Modifications may be made to the chiller described above. For example, instead of the drum having a perforated peripheral wall it may be adapted in any practicable way to be - 6 liquid permeable. The drive and support arrangement may be used in conjunction with known systems for circulating liquid through it through the chiller. The drive may be transmitted to the drum by rollers which engage frictionally with tracks on the drum.

By inclining the axis of rotation of the drum downwards from its forward end to its rearward end, a greater depth of water is found at the rearward end, away from the door and where the bags tend to accumulate. Within the scope of the invention the axis of rotation of the drum may be horizontal. In any case, the drive system could be provided at the forward end of the drum, provided that space is made available under the top panel of the cladding, especially if an externally toothed ring gear is used so as to avoid obstructing the open end of the drum.

Provided that use is made of an externally toothed ring gear or chainwheel, and a cylindrical ring is provided on the drum to mount the chainwheel, and sufficient headroom is provided to accommodate the motor, the drive system may be provided at any position along the length of the drum. Also, within the scope of the invention, a drive system may be provided at both ends of the drum.

Notwithstanding the various alternatives discussed above, the illustrated embodiment Is to be preferred because of the constructional and operational advantages it offers. - 7

Claims

CLAII\IIS 1. A chiller for articles, particularly in the form of bagged

food products, including a casing and a drum supported within the casing for rotation about an axis which is horizontal or inclined to the horizontal, the casing being adapted to contain a bath of cooling liquid for articles deposited within the drum, wherein rotary drive means for the drum are positioned above the axis of the drum and spaced 1 0 therefrom.
2. A chiller for articles, particularly in the form of bagged food products, including a trough-like casing and a drum supported within the casing for rotation about an axis which is horizontal or inclined to the horizontal, the casing being adapted to contain a bath of cooling liquid and the peripheral wall of the drum being adapted to allow liquid to pass therethrough, rotary drive and support means being spaced from and above the axis of the drum and the liquid level, the drive means being coupled to rotary driven means associated with the drum and at least partially immersed in the liquid.
3. A chiller as claimed in Claim 2, wherein the drum has a forward open end through which the articles are to be introduced, and the drive means for the drum is associated with the rearward end of the drum.
4. A chiller as claimed in Claim 2 or Claim 3, wherein the drive means includes a pinion which is supported by a support structure of the chiller and drivable by a motor, the pinion meshing with a driven means comprising a ring gear fast with the rearward end of the drum.
5. A chiller as claimed in Claim 4, wherein the axes of the pinion and the drum both lie in the same vertical plane.
6. A chiller as claimed in Claim 4 or Claim 5, wherein the ring gear is mounted on the radially inner side of an axially projecting cylindrical flange forming part of or - 8 associated with the drum.
7. A chiller as claimed in any of Claims 4 to 6, wherein support means for the rearward end of the drum comprises a pair of rollers, the axes of which are disposed one on each side of the vertical plane in which lies the axis of the drum.
8. A chiller as claimed in Claim 7, wherein the rollers bear against the radially inner side of the flange.
9. A chiller as claimed in Claim 7 or Claim 8, wherein shafts of the pinion and rollers are mounted in a support plate carried by the support structure of the chiller.
10. A chiller as claimed in Claim 9, wherein a motor for driving the pinion is mounted on the support plate, and a second pair of rollers mounted on the plate bear against an annular track provided on the rearward end wall of the drum.
11. A chiller as claimed in Claim 10, wherein the motor is mounted on of the opposite side of the plate to the pinion.
12. A chiller as claimed in any of Claims 2 to 11, wherein the axis of the drum is inclined downwards from its forward end.
13. A chiller as claimed in any of Claims 2 to 12, wherein support means for the forward end of the drum comprises a pair of rollers bearing on the radially inner side of a cylindrical flange forming part of or associated with the forward end of the drum, the axes of the rollers being disposed one on each side of the vertical plane in which lies the axis of the drum.
14. A chiller as claimed in ay of Claim 2, wherein the drive means for the drum comprises a sprocket drivable by a motor and engaging with a chain extending around and fast with the rearward end of the drum or a part associated with the rearward end of the drum.
15. A chiller as claimed in Claim 14, wherein the chain is rigid with the radially inner - 9 - side of a cylindrical flange forming part of or associated with the rearward end of the drum.
16. A chiller as claimed in any of Claims 2 to 15, in which the drum is removable from within the casing by raising the drum vertically after removing or displacing support means at the forward end of the drum or both support and drive means at the rearward end of the drum.
17. A chiller including a drum for tumbling articles to be cooled in a bath of liquid, the drum being drivable in rotation by a mechanism comprising a ring gear associated with the drum and a pinion meshing with the ring gear, the pinion being coupled to drive means, the level of liquid in the bath being such that the ring gear is immersed in the liquid but at least the bearings of the pinion are disposed above the liquid level.
18. A tumble chiller as claimed in Claim 17, wherein rollers supporting the drum for rotation are arranged above the liquid level.
19. A tumble chiller as claimed in Claim 18, wherein rollers engaging the drum so as to limit movement in the direction parallel to its axis are arranged above the liquid level.
20. A chiller as claimed in Claim 18 or Claim 19, wherein the drum is supported by laterally spaced rollers engaging the radially inner sides of flanges at front and rear ends of the drum.
21. A chiller as claimed in any of Claims 17 to 20, wherein the ring gear is constituted by a roller chain and the pinion by a sprocket.
22. A chiller as claimed in Claim 20, wherein the rollers at one end of the drum are movable to allow the drum to be Remounted.
23. A chiller as claimed in any preceding claim wherein the drum is enclosed by a cooling jacket and the drum is provided with means for causing cooling liquid in - 10 which the drum is immersed to be passed across the surface of the jacket, and means for circulating coolant through the jacket.
24. A chiller as claimed in Claim 23, wherein passageways for conducting cooling liquid are arranged beside both major surfaces of the jacket.
25. A chiller as claimed in Claim 23 or Claim 24, wherein the cooling jacket constitutes a lower part of an inner casing for the drum, slots extending through the casing in the vicinity of the liquid level, and wherein the inner casing is enclosed by an outer casing so as to form an outer passageway for cooling liquid, the drum being adapted to cause liquid to circulate through the outer passageway.
26. A chiller as claimed in Claim 1, wherein a cooling jacket is interposed between the drum and the casing and means is provided to cause coolant to be passed through the cooling jacket, the drum being adapted to cause liquid to flow through a first passageway between the drum and the cooling jacket into a second passageway between the cooling jacket and the casing, such that cooling liquid enters the second passageway on one side of the drum and flows therethrough in contact with the cooling jacket to return into the first passageway on the opposite side of the drum.
27. A chiller as claimed in any of Claims 23 to 26, wherein the drum is provided with projections to promote circulation of cooling liquid.
28. A chiller as claimed in Claim 27, wherein the projections have the form of scoops.
29. A chiller for articles, particularly in the form of bagged food products, including a casing and a drum supported within the casing for rotation about an axis which is horizontal or inclined to the horizontal, the casing being adapted to contain a bath of cooling liquid for articles deposited within the drum, the drum being adapted to permit the passage of cooling liquid therethrough, the drum having peripheral flanges at its forward and rearward ends, support means for the drum comprising rollers engaging the flanges in an upper region of the drum above the level of the - 11 cooling liquid, and means for driving the drum in rotation.