GB2186674A - A horizontal plate freezer - Google Patents

Abstract

A horizontal plate freezer has a stack of freezer plates comprising an upper group and a lower group of plates. An upper pressure frame 12 overlies the upper group and a lower pressure frame 11 lies between the groups. Hydraulic piston and cylinder arrangments 22, 23 engage the upper frame 12 to lift it sufficiently to move the plates of the upper group relative to each other to an open place spacing in which products can be loaded and unloaded in the space between adjacent plates. In the first condition with all plates in closed spacing for freezing product, the stack has a first height, which will increase to accommodate the opening of the upper group of plates to the open spacing condition. Hydraulic piston and cylinder arrangements housed in guides 17, 18 engage the lower frame 11 to move the plates of the lower group to open space condition and close the upper group to closed spacing, in so doing the lower frame 11 raising the lowermost plate of the lower group from its initial position and closing the upper group to closed spacing. Raising the lower frame does not increase the stack height. Lowering of the lower frame will return the plates of the lower group to the intitial condition in closed spacing and lowering the upper frame returns the upper group to closed spacing, and the stack height to the first height. <IMAGE>

Description

SPECIFICATION Horizontal plate freezers This invention is concerned with horizontal plate freezers. Such freezers comprise a stack of superposed horizontal freezer plates which can be moved relative to one another by a lifting device which acts to raise the uppermost plate and through that plate each of the plates beneath, to position the plates at a first or open inter plate spacing for loading and unloading product into and out of the space between each pair of adjacent plates, commonly referred to as a station, the product usually being on trays.Lowering of the uppermost plate will then allow all the plates again to move relative to one another to reduce the inter place spacing to a second or closed inter plate spacing for the cooling cycle to occur, the product in each station then being in contact with the plate on which it was placed during loading and in close proximity to the plate above it for efficient heat extraction from the product by the plates defining that station.

Horizontal plate freezers are often located, particularly on board ship, in areas where there is a height restraint, while as many stations as possible are required within that height constraint. As one result the lowest stations are near floor level. Product to be handled is usually in elements of 10 to 20 kgs which makes handling of product at the lowest stations difficult.

In a known arrangement for providing a plate loading and unloading height which is common to all plates and at a suitable height above floor level, there is provided a first frame which can be raised hydraulically which, starting with the plates in closed inter plate spacing, will raise the uppermost plate until all the plates are suspended from it in open plate spacing. In so doing, if the uppermost plate is initially at a suitable height for unloading by an operator, which will be called the operating height, that plate and each of a number of the upper plates immediately following the uppermost can be unloaded on reaching the operating height. When the frame has all of the trays suspended, a second lifting device operates to raise the plate now at the operating height.The effect of this is to close the upper plates which were unloaded, and sequentially present the next succeeding group of plates to the operating height. When the lowest of those has been unloaded, a third hydraulic lifting device will raise the plate now at the operating height and sequentially present the lowermost group of plates sequentially to the operating height. When these plates have been unloaded the operation can be reversed with each plate being loaded as it reaches the operating height, until all of the plates are loaded and have, on completion of the lowering of the frame, returned to the closed spacing for the next cooling cycle. It will be seen that the height required for such a freezer is that necessary to accommodate all of the plates in open plate spacing.

According to the present invention there is provided a horizontal plate freezer comprising a stack of freezer plates including an upper group of freezer plates and a lower group of freezer plates, which stack in the freezing cycle has adjacent plates in a closed spacing and the stack having a first height, means to move the upper group of plates to an open spacing while the lower group remain in the closed spacing, at which state the stack has an increased height accommodating the upper group in open spacing and the lower group in closed spacing, means to move the lower group to an open spacing, to raise the lowermost plate of the lower group above its initial position and to move the upper group of plates to closed spacing while the increased stack height remains unchanged.

In order that the invention may be well understood, there will now be described an embodiment thereof, given by way of example only, reference being made to the accompanying drawings in which, Figs. 1, 2 and 3 show schematically the presently preferred embodiment of the invention in different stages of operation, all of the views being end elevations, and Figs. 4 and 5 are respectively a perspective view with one corner cut away and a plan view of the preferred embodiment showing the lifting and lowering cylinders and frames.

Referring to Figs. 1 to 3 there are two moving frames E and F. The upper moving frame E will support an upper group of plate, in fact the majority, whilst the lower frame F will support a lower group of 4-5 plates.

Starting with the elements of product loaded in the stations i.e. between all plates and the plates in the closed freezing inter plate spacing, the stack has a first height with all plates at minimum spacing. To unload the freezer the upper frame E Fig. 1 is raised to move the plates of the upper group to open inter plate spacing, suspended from each other and from frame E. The stations of the upper group are unloaded. When the upper group of stations has been unloaded the upper moving frame E is in its upper position, and the stack has an increased height with the upper plates at open spacing and the lower plates at closed spacing. The lower moving frame F can now be raised to its upper position as shown in Fig. 3 with the lower group of plates suspended from each other and from plate F at the open inter plate spacing.In this condition the lowest station is presented to the operator at a convenient unloading height above floor level indicated by arrow G, which is above the level of the lowest plate of the lower group in the freezing lower position of the lower group.

The lower moving frame F may be used to close up the upper group plates after the product has been removed from the upper stations but the stack height remains unchanged.

When reloading the freezer the lower stations are loaded first and then the frame F is lowered to lower the lower group to the lower freezing closed inter plate spacing. Lowering frame F may be used to open the upper stations for loading.

When the lower stations have been closed and the upper stations loaded, frame E lowers the upper stations to their lower position in the closed inter plate spacing for freezing.

The control and synchronisation of the moving frames can be carried out by hydraulic or mechanical means.

It will be appreciated that the plate stack height requirement is the height required for the upper group of plates to be suspended in open plate spacing plus the height of the lower group in closed plate spacing and only two lifting means are required. The arrangement provides a position for every plate at which it can be loaded and unloaded conveniently by an operator.

Referring now to Figs. 4 and 5, three main horizontal frames 10, 11 and 12 are shown, frame 10 being fixed, frame 11 being a lower pressure frame and frame 12 an upper pressure frame. Frames 11 and 12 have oppositely directed end guides of which one, 13, can be seen and 15, 16 respectively. Guides 13 and 15 are movable along vertical guide member 17, while the oppositely directed guides of which one, 16 can be seen, engage guide 18. A head frame 19 spans guides 17, 18. A pair of hydraulic cylinders is provided for each pressure frame, cylinder 20 located in guide 1 7 and another not shown but located in guide 18, operate the lower pressure frame 11 while cylinders 22, 23 operate upper pressure frame 12. Cylinders 20, 21 are symmetrically ppsitioned relative to the guide members while cylinders 22, 23 are located on the opposite sides of the guide members.

The freezer is shown in Fig. 4 in the freezing closed spacing of the plates, corner 24 having been cut away to reveal the furthermost cylinder 23.

Suspension bolts 25 can be seen, each of which passes through a pair of adjacent plates, each bolt head 26 resting on the upper plate of the pair and a bolt lifting stop, not shown, lying beneath and spaced from the under face of the lower plate of the pair.

In operation, starting with the closed spacing, upper pressure frame 12 is raised by cylinders 22, 23 causing lifting bolts in the upper pressure plate to raise the top freezer plate, spacing the top plate from frozen product and then will lift that next plate through the bolt lifting stops.

This continues until the plates above the lower pressure frame have all been spaced and unloaded. The unloading of the frozen product from between the uppermost pair of the plates can be effected at the starting level of the lower plate of the top pair or at any level of that lower plate to the upper limit of its travel.

The lower pressure frame is raised when the plates above it have been unloaded and the operation is repeated for the plates below the lower pressure frame whose upper limit of travel is dictated by the bunching by it of the plates above it. This may be limited by stops which are provided between adjacent plates to prevent crushing of product when plates are loaded and are moved to the closed spacing to bring the lowermost freezer plate up to a level which will be then at a height more convenient to the operator than floor level.

To load the freezer, the operation described above is reversed until the original closed spacing of all plates with product between adjacent plates is resumed.

Claims (6)

1. A horizontal plate freezer comprising a stack of freezer plates including an upper group of freezer plates and a lower group of freezer plates, which stack in the freezing cycle has adjacent plates in a closed spacing and the stack having a first height, means to move the upper group of plates to an open spacing while the lower group remain in the closed spacing, at which state the stack has an increased height accommodating the upper group in open spacing and the lower group in closed spacing, means to move the lower group to an open spacing, to raise the lowermost plate of the lower group above its initial position and to move the upper group of plates to closed spacing while the increased stack height remains unchanged.

2. A freezer according to claim 1 in which the upper group of plates is movable to open spacing by hydraulic cylinders and the lower group is moved to open spacing and the lowermost plate raised by means of hydraulic cylinders.

3. A freezer according to claim 2 in which each group includes a pressure frame operable to raise the plates of that group to open spacing, the lower group frame also serving to raise the lowermost plate, each pressure frame including a pair of oppositely projecting guide means, like directed guide means engaging one of a pair of guide members.

4. A freezer according to claim 3 in which a pair of hydraulic cylinders is provided for one pressure frame, one cylinder of the pair engaging one guide means of that frame to one side of the related guide member and the qther cylinder of the pair engaging the other guide means on the opposite side of the other guide member.

5. A freezer according to claim 4 in which a pair of hydraulic cylinders is provided for the other pressure frame, each cylinder being coupled to one of the guide members and being symmetrically positioned relative to the guide members.

6. A horizontal plate freezer substantially as herein described with reference to the accompanying drawings.