GB2035939A - A system for conveying goods into and out from a freezing chamber - Google Patents

Abstract

A system for continually conveying goods into and out from a freezing chamber 1 of the type having a stack of horizontal plates 2 movable vertically to bring each plate in turn to a transfer position adjacent an inlet to the chamber includes a loading station for depositing unfrozen goods on trays 5 on a continuously moving conveyor 4 for transfer to a feed conveyor 6 which conveys them at a constant rate to a feed position 7 adjacent the inlet. A pusher device pushes successive bunches of trays bunched at the feed position on to a plate 2 at the transfer position so as to fill each successive plate, each bunch of trays simultaneously pushing a bunch of trays carrying goods frozen in the chamber out on to a discharge conveyor 8 which preferably returns them, via an unloading position and a washing station for the trays, to the loading station. The system is characterised in that the time taken for accumulating a bunch of trays at the feed position 7 is substantially equal to or greater than the time required for lowering the stack of plates from the upper to the lower part of the chamber to return the uppermost plate to the transfer position so as to allow the pusher device to be operated at a constant rate. <IMAGE>

Description

SPECIFICATION A system for conveying goods into and out from a freezing chamber The present invention relates to a conveyor system for conveying goods into and out from a freezing chamber.

In a known type of freezing chamber, packaged goods to be frozen are pushed on to one of a plurality of plates at a transfer position within the chamber, the filled plate then being moved upwardly and an empty plate being brought into the transfer position. When all the plates have been filled they are moved downwardly to bring the uppermost plate, which was filled first, back to the transfer position for unloading of the goods, which have been frozen during their period in the freezing chamber, the plates being moved upwardly in steps for successive unloading.

In this type of chamber, unloading of the goods may take place simultaneously with refilling of the plates, each plate, when brought to the transfer position being unloaded and refilled such that loading, freezing and unloading takes place in a continuous cycle. At present the loading and unloading is effected by a conveyor system which feeds a line of packaged goods to a feed position adjacent an elongate inlet in one side of the chamber and a pusher device which pushes the line of packages through the opening in a direction perpendicular to the feed direction, on to a plate at the transfer position within the chamber.A further line of packages is then fed to the feed position and pushed on to the plate, simultaneously pushing the previous line already on the plate further into the chamber, this system being continued until the plate is full and subsequent plate is moved up into the transfer position. If the plate is already full of frozen goods, the pushing of a line of unfrozen packages on to a plate simultaneously pushes a line of frozen packages, at the far side of the chamber from the inlet, out on to a discharge conveyor.

The above, known loading system for such a freezing chamber has several disadvantages.

Firstly, since the unfrozen goods are pushed against each other and against the frozen foods during the loading and discharge cycles, the system can only be used for packaged goods and, even so, a breaking stroke is required to free the frozen goods from the plates before the unfrozen goods are pushed against them in order to avoid deformation of the unfrozen packages.

Secondly, a greater time elapses during the lowering of all the plates from the upper to the lower part of the chamber than during the raising of the plates through one step. The otherwise regular feed of lines of packages into the chamber must therefore be halted during the lowering stage, resulting in a build up of packages at the feed position and a need for complex timing controls for coordinating the movement of the pusher device with that of the plates.

The object of the present invention is to provide a conveying system which can convey unpackaged goods into a freezing chamber of the type described above and which employs a simpler timing system for the feed mechanisms.

According to the present invention, there is provided a continuous system for conveying goods into and discharging them from a freezing chamber of the above type, including a plurality of trays for carrying the goods, a feed conveyor for conveying the trays to, and bunching them at a feed position adjacent an inlet to the freezing chamber, transfer means for moving each successive bunch of trays from the feed position on to each successive plate at the transfer position in the freezing chamber, the said group of trays simultaneously pushing a group of trays on the said plate through an outlet in a wall of the freezing chamber opposite the inlet, in use of the system, and a discharge conveyor for receiving trays discharged through the outlet and conveying them to an unloading position where the frozen goods are removed, characterised in that the feed conveyor delivers the trays at a constant rate, in use, such that the time taken for accumulating a bunch of trays at the feed position is substantially equal to or greater than the time required for lowering the plates from the upper to the lower part of the chamber, the transfer device also operating at a constant rate to move the successive bunches of trays onto the plates.

The freezing chamber is preferably of the type having a refrigerant fluid fed to internal cavities in the plates to effect freezing, but freezing may be carried out by any convenient means, such as a flow of cold air through the chamber.

The use of trays for carrying the goods in the present invention allows unpackaged goods to be fed into such a freezing chamber to be frozen and also allows a greater quantity of goods to be accumulated at the feed position for loading into the chamber with one movement of the transfer device than was previously possible. This reduces the number of movements of the transfer device required to fill a plate and hence increases the time interval between these movements while allowing the overall time for rolling the plate to be maintained substantially the same as required by the previous method.The time interval between movements of the transfer device is in fact increased to be substantially equal to the time required for lowering all the plates so that there is no need for any change in this time interval during the operation of the freezing chamber, thus simplifying the timing control of the feed mechanism.

The use of trays also obviates the necessity for a breaking stroke in the feed cycle since it is the trays and not the goods which are pushed against each other and no damage occurs when trays carrying unfrozen goods are pushed against those carrying frozen goods to release the trays and discharge them from the chamber. A breaking stroke may, however, still be employed.

The feed conveyor preferably feeds the trays to the feed position in a direction perpendicular to the direction of movement of the trays into the chamber, the transfer device preferably comprising a pusher device. The trays are preferably elongate in their direction of movement into the chamber and are bunched such that longitudinal edges of adjacent trays touch.

The conveyor system of the present invention preferably also has a loading station at which empty trays are loaded with goods to be frozen in the freezing chamber. In a preferred embodiment of the invention the loading station is located in the path of an auxiliary conveyor which receives empty trays coming from the discharge conveyor, after unloading of goods frozen in the freezing chamber, and transfers the trays, after loading, on to the feed conveyor. The loading station preferably has a deposit head which deposits unfrozen, unwrapped goods such as icecream blocks, on to the trays.

The discharge conveyor may convey the unloaded trays to a station remote from the freezing chamber, for example, for washing, the trays being returned to the auxiliary conveyor by a further conveyor. Preferably, however, the discharge conveyor returns the trays directly to the auxiliary conveyor, any additional station, for washing or other processes, being provided in the path of the conveyor.

The system of the present invention can thus accommodate all the necessary operations for the feed cycle for the freezing chamber in a relatively compact space around the chamber.

Preferably the feed, discharge and auxiliary conveyors are driven by a common drive unit, the auxiliary conveyor preferably being driven for continuous movement, and the feed discharge conveyors being driven for regular, intermittent movement, the respective movements being controlled from a common control console to coordinate the conveyance of the trays with the movement of the plates within the freezing chamber. The conveyance of the trays is preferably by a positive drive mechanism, that is, the plates preferably have elements engageable with cooperating elements of the conveyors to be carried thereby.

One embodiment of the invention will now be more particularly described, by way of example, with reference to the accompanying purely diagrammatic drawings, in which: Figure 1 is a perspective view of a conveyor system according to the invention shown in use for conveying goods into and out from a freezing chamber; and Figure 2 is a plan view of the system of Fig.

1.

Referring to the drawings, a freezing chamber is shown generally indicated 1 and contains seven, rectangular, internally-cooled freezing plates 2, mounted one above the other, and displaceable verticaily by conventional means (not shown).

A conveyor system for conveying goods 3a to be frozen in the chamber 1 is also shown and includes a continuously moving conveyor 4 which carries elongate, rectangular, stainless steel trays 5 for receiving the goods 3ato be frozen, a feed conveyor 6 which receives the loaded trays 5 and feeds them to a feed position 7 adjacent the freezing chamber 1 and a discharge conveyor 8 which receives the trays 5 carrying goods 3b frozen in, and discharged from the chamber 1 and carries them to an unloading station 9. The discharge conveyor 8 also conveys the unloaded trays 5 back to the conveyor 4.

In further detail, the conveyor 4 extends along one side of the chamber 1, beneath the discharge head 10 of a conventional depositor which extrudes blocks of icecream, comprising the goods 3a, on to the trays 5 which are arranged with their longitudinal axes aligned with the feed direction of the conveyor 4.

Each tray receives six blocks 3 a as it passes beneath the head 10. The conveyor 4 deposits the trays 5 successively on the feed conveyor 6 which extends perpendicularly to the conveyor 4 and is operated discontinuously, that is, it is maintained stationary while each successive tray 5 is deposited at a respective receiving location thereon and then conveys the trays towards the feed position 7, in a direction perpendicular to the longitudinal axis of the tray, to bring each successive receiving location into the position for receiving a tray from the conveyor 4. The receiving locations are defined by elements (not shown) which engage upstanding, shorter end walls II of the trays 5 to provide a positive drive for the trays.

The feed conveyor 6 feeds the trays 5 to the feed position 7 where they are bunched together against a stop 12. When seven trays 5 have been accumulated at the feed position they are pushed by a conventional pusher 13, in a direction perpendicular to the feed direction, through an inlet slit 14 in the adjacent chamber wall and on to a plate 2 located at a transfer position within the chamber 1, at the same height as the feed conveyor 6.

The pusher 1 3 then withdraws to its rest position to allow a further seven trays to be accumulated at the feed position, this bunch being pushed on to the same plate 2 as the previous bunch of trays and simultaneously pushing the said previous bunch to the centre of the plate 2 to the position shown in Fig. 1.

A plate 2 can accommodate three bunches of seven trays, the third bunch pushing both previous bunches already on the plate, across the plate substantially to fill it.

Once a plate 2 at the transfer position has been filled, all the plates 2 are moved upwardly one step to bring the plate 2 immediately therebeneath into the transfer position to be filled in its turn. The time taken for the upward movement is considerably less than the time required to accumulate a further bunch of trays at the feed position such that each successive plate to be filled is brought to the transfer position ready to receive a bunch of trays from the feed position at the next stroke of the pusher 13.

The loading of the plates is continued in this way until all seven plates have been filled and are located in the upper part of the chamber 1. During the whole loading process, refrigerant is passed through internal spaces of the plates to freeze the icecream blocks and, by the time the lowermost plate 2 has been filled, the icecream blocks on the first tray 5 fed into the chamber have been frozen to the required temperature. The plates are therefore lowered immediately to bring the uppermost plate, which was filled first, back to the transfer position for unloading, the time taken for this lowering being substantially the same as, but slightly less than, the time required to accumulate a further bunch of trays 5 at the feed position 7.

The pusher 1 3 now operates to push this further bunch of trays 5 on to the uppermost plate, the trays pushing against those already on the plate to eject one bunch carrying frozen icecream blocks 3 b through an outlet slit 1 5 in the wall opposite the inlet slit 14.

Although those trays carrying frozen goods are themselves frozen to the plates 2, no breaking stroke is required to release the frozen trays since the warmer trays engage the frozen trays by their respective upstanding end walls 11 such that sufficient force is applied to the frozen trays to release them and move then at a single stroke of the pusher.

The feed of bunches of trays to the plates 2, and pushing on to the successive plates 2 continues as described above, each bunch of trays 5 carrying unfrozen icecream blocks 3a effecting discharge of one bunch of trays 5 carrying frozen icecream blocks 3b such that the loading, freezing and unloading occurs in a continuous cycle.

The bunches of trays 5 pushed through the outlet 1 5 are received on the discharge conveyor 8 which also has elements which engage the end walls 11 of the trays to provide a positive drive. The discharge conveyor, like the feed conveyor 6, moves intermittently, being held stationary to receive each successive bunch of trays 5, and moving the bunches in a direction perpendicular to the direction of feed on to the conveyor 8, in the same sense as the conveyor 6.

At this stage the icecream blocks 3b are frozen to the trays 5 and are carried over the end of the discharge conveyor 8 to the unloading station 9 beneath the conveyor. Here the blocks 3b are released from the trays 5 by a heater 17, or alternatively by a vibrator, and fall on to a further conveyor 18 which conveys them to further stages of the manufacturing process. The conveyor 1 8 may be arranged to transport the blocks 3b in a direction perpendicular to their movement on the conveyor 8, as shown in Fig. 2, such that the blocks are discharged in a single line. Alternatively the conveyor 1 8 may be arranged as shown in Fig. 2, to convey the blocks 3b in rows in a direction parallel to the movement of the conveyor 8.

The unloaded trays 5 are carried beneath the conveyor 8 past a washing station 19, where they are cleaned ready for receiving further goods, to a transfer station 20, adjacent the continuously moving conveyor 4, where they are transferred by conventional means (not shown) on to the conveyor 4 to be fed under the discharge head 10 once more to complete their cycle through the conveying system and freezing chamber.

The conveyors 4, 6 and 8 are driven by a common drrive mechanism located in a housing 21 beneath the conveyor 4 and controlled from a control consul 22. The timing of the pusher 13, the feed of the deposit head 10 and the movement of the conveyor 1 8 are all synchronised with the movements of the conveyors 4, 6 and 8 from the control consul 22.

Although the trays 5 shown in the diagrams are of such a size that three bunches of seven trays can be accommodated on each plate 2, the trays may be of any suitable size, the feed rate of the conveyors 4, 6, 8 and the timing of the pusher 1 3 being regulated from the control consul 22 to ensure that appropriate bunches are accumulated at the feed position 7 for feeding to the plates 2 in time with the movements of the latter. Any convenient number of blocks 3a may also be deposited on a tray 5.

In the embodiment shown, rectangular blocks of icecream 3a are deposited on the trays 5 but the blocks may be of any desired shape or the trays may be formed with generally cup-shaped moulds into which a mixture of creamy consistency is poured. Any suitable apparatus for, for example, inserting sticks into icecream blocks or forming decorations on the surface of the blocks may be located between the deposit head 10 and the conveyor 6 to perform the desired operation on the blocks 3a before they are frozen. Alternatively, wrapped goods may be deposited on the trays 5.

Although the above system has been described in relation to icecream products it may be used for conveying any suitable type of goods into and out from chamber having a moving plate system as described.

Claims (14)

1. A system for the continuous conveyance of goods into and discharge of the goods from a freezing chamber of the type having a plurality of horizontal plates arranged in a vertical stack which is movable, in a continuous cycle, from a position in which the upper most plate is supported at a transfer position adjacent an inlet to the chamber, upwardly to bring each successive plate to the transfer position, and downwardly to return the uppermost plate to the transfer position, the system including a plurality of trays for carrying the goods, a feed conveyor for conveying the trays to, and bunching them at a feed position adjacent the inlet to the freezing chamber, transfer means for moving each successive bunch of trays from the feed position on to a plate at the transfer position in the freezing chamber so as to fill each successive plate, each bunch of trays simultaneously pushing a bunch of trays on the said plate through an outlet in a wall of the freezing chamber opposite the inlet, and a discharge conveyor for receiving trays discharged through the outlet and conveying them to an unloading position where the frozen goods are removed, and in which the feed conveyor delivers the trays at a constant rate, in use, such that the time taken for accumulating a bunch of trays at the feed position is substantially equal to or greater than the time required for lowering the plates from the upper to the lower part of the chamber, the transfer device also operating at a constant rate to move the successive bunches of trays on to the plates.

2. A system as claimed in Claim 1, in which the feed conveyor is arranged to feed the trays to the feed position in a direction perpendicular to the direction of movement of the trays into the chamber.

3. A system as claimed in Claim 2, in which the trays are elongate in their direction of movement into the chamber and are bunched with longitudinal edges of adjacent trays touching.

4. A system as claimed in Claim 1, Claim 2 or Claim 3, further including a loading station for the loading of empty trays with goods to be frozen in the chamber, in use of the system, and means for conveying empty trays from the unloading position to the loading station.

5. A system as claimed in Claim 4, in which the loading station is located in the path of an auxiliary conveyor arranged to receive empty trays directly from the discharge conveyor and to transfer the trays, after loading, on to the feed conveyor.

6. A system as claimed in Claim 5 as dependent on Claim 3, in which the feed conveyor and the discharge conveyor are arranged to convey the trays in respective directions perpendicular to the direction of movement of the trays into and out from the chamber and in which auxiliary transfer means are provided for transferring individual trays successively from the discharge conveyor on to the auxiliary conveyor and from the auxiliary conveyor on to the feed conveyor in directions perpendicular to their directions of movement on the discharge and feed conveyors.

7. A system as claimed in Claim 4, Claim 5 or Claim 6, in which the loading station has a deposit head for depositing unfrozen, unwrapped goods on the trays.

8. A system as claimed in Claim 7, in which the trays are substantially planar and the loading head is arranged to deposit blocks of unfrozen goods on the trays.

9. A system as claimed in Claim 7, in which the trays have recesses for receiving unfrozen goods.

10. A system as claimed in Claim 7, Claim 8 or Claim 9, as dependent on Claim 5 or Claim 6, in which a washing station for washing the trays is provided in the path of the discharge conveyor between the unloading position and the position for the transfer of the trays on to the auxiliary conveyor.

11. A system as claimed in any preceding claim, in which each tray has elements engageable with cooperating elements of each conveyor to receive drive therefrom.

1 2. A system as claimed in Claim 11, in which the elements comprise upstanding walls at the front and rear end of each tray with respect to the direction of motion of the trays into the freezing chamber.

1 3. A system as claimed in any preceding claim, in which the transfer means for transferring the trays from the feed position into the chamber comprise a pusher device.

14. A system as claimed in any preceding claim, including a common drive unit for driving the movements of each of the conveyors.

1 5. A freezing chamber of the type having a plurality of horizontal plates arranged in a vertical stack which is movable, in a continuous cycle, from a position in which the uppermost plate is supported at a transfer position adjacent an inlet to the chamber, upwardly to bring each successive plate to the transfer position, and downwardly to return the uppermost plate to the transfer position, and a system for the continuous conveyance of goods into and discharge of the goods from the freezing chamber as claimed in Claim 14, including a control unit for controlling the drive unit to drive the feed and discharge conveyors for regular intermittent movements and also for controlling the movements of the stack of plates within the freezer in synchronism with the movements of the conveyors such that the feed conveyor, the plates and the discharge conveyor are held stationary during transfer of a bunch of trays from the feed conveyor on to a plate and simultaneous pushing of a bunch of trays from that plate on to the discharge conveyor, the stack of plates being moved upwardly or downwardly during bunching of trays at the feed position.

1 6. A freezing chamber and a system as claimed in Claim 1 5 as dependent on Claim 5, in which the control unit controls the drive unit to drive the auxiliary conveyor continuously and to hold the feed conveyor stationary during transfer thereto of a tray from the auxiliary conveyor and to hold the discharge conveyor stationary during transfer therefrom of a tray to the auxiliary conveyor.

1 7. A system for the continuous conveyance of goods into and discharge of the goods from a freezing chamber of the type having a plurality of horizontal plates arranged in a vertical stack which is movable, in a continuous cycle, from a position in which the uppermost plate is supported at a transfer position adjacent an inlet to the chamber, upwardly to bring each successive plate to the transfer position, and downwardly to return the uppermost plate to the transfer position, substantially as herein described with reference to, and as shown in the accompanying drawings.

1 8. A method of conveying goods continuously into and discharging them from a freezing chamber of the type having a plurality of horizontal plates arranged in a vertical stack which is movable, in a continuous cycle, from a position in which the uppermost plate is supported at a transfer position adjacent an inlet to the chamber, upwardly to bring each successive plate to the transfer position, and downwardly to return the uppermost plate to the transfer position, in which the goods are loaded on to trays and conveyed by a feed conveyor which delivers them at a constant rate to a feed position adjacent the inlet to the freezing chamber, the trays being bunched at the feed position, each successive bunch of trays is transferred from the feed position on to a plate at the transfer position in the chamber, the bunched trays being transferred so as to fill each plate successively with trays of unfrozen goods and so as simultaneously to push a bunch of trays carrying frozen goods through an outlet in a wall of the freezing chamber opposite the inlet on to a discharge conveyor which conveys them to an unloading station, the time taken for accummulating a bunch of trays at the feed position being substantially equal to or greater than the time required for lowering the plates from the upper to the lower part of the chamber.