Ice making machine

Abstract

 An ice making machine of the type comprising a water tank (13) and freezing surfaces (18) such as fingers which are periodically contacted with water in the tank (13) to generate nodules of ice thereon includes an openable closure (17) on a side of the water tank (13) interposable under the ice on the freezing surfaces (18). Periodically, the freezing process is stopped, the water level in the tank (13) is lowered, the side closure (17) of the tank is opened and positioned under the ice on the freezing surfaces, the ice falling from the freezing surfaces (18) and being guided to a storage compartment (2) by the side closure (17).

Description

[0001] The present invention relates to an ice making machine and in particular to an ice making machine which operates on a continuous cycle.

[0002] Ice making machines are known in which projections such as fingers through which a liquid refrigerant is circulated are surrounded with water so that ice forms on the outer surfaces of the projections. At intervals the water is removed and the ice which remains on the projections can then be removed, usually by moving the row of fingers with ice thereon to a collecting area. The present invention is intended to provide an improved ice making machine using this system.

[0003] The present invention provides an ice making machine comprising a water tank, at least one localised freezing surface in the water tank capable of generating a nodule of ice upon contact with water, means for cooling said freezing surface to a freezing temperature, means for filling the tank with water to a first level at which the freezing surface contacts the water and for lowering the level periodically to a second level below any ice formed on the freezing surface, an ice storage receptable accessible by hand, an openable closure on a side of the water tank and a movable guide surface interposable under the ice when the water is at the second level and the said closure is open to guide ice falling from the freezing surface to the receptacle through the said closure, the machine being arranged to operate in successive freezing cycles with intermittent thawing periods during which the ice is guided to the receptacle.

[0004] Preferably the moveable guide surface also constitutes the closure. The guide surface is preferably a panel pivotally mounted along the bottom edge of the side opening in the tank so as to pivot between an upright position in which it closes the side opening and a sloping position in which it forms a chute for ice falling from the freezing surface. The panel is preferably arranged to be thrust upwardly by water pumped into the tank, and held there by the pressure of the water, and preferably comprises a hollow body so that it is held also by bouyancy in its upright position when the water is at the upper level but which falls under the influence of gravity to its sloping position when the water falls to its lower level. The water is preferably circulated into and out of the water tank by a pump. The freezing surface is preferably formed on a plurality of projections such as elongate fingers, through which a fluid refrigerant can be circulated. The device preferably includes means for warming the freezing surface(s) to release the ice nodules.

[0005] A preferred embodiment of the present invention will now be described with reference to the accompanying drawings wherein:

Figure 1 is a perspective view of an ice making machine embodying the present invention, the top of the machine being removed;

Figure 2 is a vertical cross-section on the line 2-2 in Figure 1;

Figure 3 is an enlarged view of a part of the apparatus of Figure 2;

Figure 4 is a perspective view of the upper part of the water tank of the apparatus of Figures 1 to 3;

Figure 5 shows the freezing finger unit of the device of Figures 1 to 4;

Figure 6 is a detailed view of one freezing finger and an ice sensing device and

Figure 7 is a schematic diagram showing the cooling and pumping circuits of the device.

[0006] Referring first to Figure 1, an ice making machine comprises a housing 1 in which is located a storage compartment 2 for ice. This compartment has an insulated wall 11 as shown in Figure 2. This insulating wall may for example comprise a vacuum jacket. On the bottom of the tank are a drain-hole 32 and a raise stainless steel floor 33 to prevent ice from blocking the drain-hole. At the front of the housing 1 is a rectangular opening normally kept closed by a flap 3 mounted on the housing 1 by a hinge 5 along its bottom edge. The flap 3 can be biased towards its vertical closed position. A handle 4 is provided for opening the flap.

[0007] In the top of the housing 1 there are provided a condenser 6 and pump 8, both comprising part of a liquid coolant refrigeration system 6 of a generally known type which is shown schematically in Figure 7 and also includes a capillary 45 an evaporation chamber 46 and a freezer manifold 19. The condenser and the pump are both ventilated to the atmosphere through louvres 7.

[0008] The housing 1 may suitably be made of sheet metal such as steel or aluminium. On the front of the housing inside the flap is provided a control panel 10.

[0009] Referring to Figures 2 and 3, a water storage tank 12 and a water circulating pump 14 are supported by a metal supporting frame 27. The storage tank can for example be supplied from the main, a solenoid valve being provided to switch the supply on when a float in the tank falls below a predetermined level. Above the water storage tank 12 is an ice making tank 13. In use, water is pumped from the storage tank 12 through a pipe 15 to the pump 14 and thence through a pipe 16 to the ice making tank 13. A hollow flap 17 is pivotally mounted on the ice making tank 13 by hinges 20. The inside of the flap 17 is made water-tight so that as the level of water rises in the tank 13 the flap 17 pivots upwardly, under its own bouyancy, from a position B (as in Fig.2 and as shown in broken lines in Fig.3) to a position A (as shown in Fig.3) in which it closes off a rectangular opening 28 in a front wall 29 of the tank 13. A rubber sealing strip is positioned along the lower inside edge of the front wall 29 above the opening 28. The water is thus able to rise to the level C shown as a broken line in Fig.3 before flowing over the top of the wall 29 at the front of the tank and back down into a silt trap 21 and thence back into the water storage tank 12. A siphoning pipe 22 is provided for removing silt from the silt trap 21. An elongate metal guide strip in front of the wall 29 prevents the overflowing water from entering the ice storage compartment.

[0010] A flap 60, pivotally mounted at 61 on the wall 23 of the tank, overlies the flap 17 in its position B (shown in dotted lines) and, when the flap 17 rises to position A, is lifted by flap 17 to the position shown in full lines in Fig.3. The flap 60 is perforated to allow water to pass through it, but any ice which might accidentally fall from one of the fingers when flaps 17,60 are up, will be caught by the flap 60 and guided into the storage compartment when the flaps next fall to position B. Flap 60 could alternatively be pivoted along the free edge of flap 17, its own free edge resting on an enlarged wall 23 of the tank.

[0011] At the top of the tank 13 are provided three rows of hollow cooling fingers 18 the upper ends of which are connected to manifolds 19 through which is circulated a coolant from the refrigeration unit 6 by the pump 8. When the water is at its upper level C as shown in Fig.3, a substantial part of each finger is immersed in the water. The circulating coolant causes the temperature of the outer surfaces of the fingers 18 to fall below 0°C so that ice begins to collect along the fingers as shown at 26 in Fig.3.

[0012] The arrangement of the manifolds 19 is shown in Fig.5. A fluid refrigerant such as FREON 12 (FREON is a Registered Trade Mark) passes through each of the manifolds 19 in turn from an inlet pipe 38 to an outlet pipe 39. As can be seen in Fig.6., the fluid is guided into each finger by a baffle strip 37 extending from the top of the manifold 19 towards the bottom of the finger 18. The fluid passes under the bottom edge of the baffle plate and back up to the manifold. The fingers on adjacent manifold are in staggered formation to prevent ice noduels interfering with one another.

[0013] Adacent one of the fingers 18 (see Fig.6) is a sensing element 40 which is connected to a similar element 49 placed elsewhere in the tank at a fixed position which is below the level of water during the freezing cycle, via a conductivity measuring device 48 (see Fig.7) which measures the electrical conductivity between the two sensing elements. The element 40 comprises a metal electrode 42 (of known type) which faces the finger and is set in an insulating block 43. When an ice nodule of the desired size builds up on the finger, the ice covers the surface of the electrode 43 thus altering the measured conductivity, in response to which the pump 14 is stopped.

[0014] The automatic control of the machine works as follows. An appropriate voltage is supplied from a power supply unit P (Fig.7). When the formations of ice on the fingers 18 have reached a desired size, the reduction in the measured conductivity causes the pump 14 to be stopped and the water runs back through the pump from the ice making tank 13 to the storage tank 22. The signal from the conductivity measuring unit 48 also actuates a timing device 50 which restarts the pump after a predetermined time interval. As the level of water in the tank 13 falls the flap 17, being no longer supported by the water, falls back to the position B under the influence of gravity. As it falls, it triggers a microswitch 41 (best seen in Fig.4). This actuates a 3-way valve 44 (for example a solenoid valve) which causes the circulation of coolant fluid to bypass the capillary 45 and evaporation chamber 46 of the refrigeration unit 6 so that instead of passing through the fingers as a cold gas it passes through a conduit 47 and through the fingers in the form of a relatively warm liquid. The temperature of the fingers 18 beings to rise and the ice formations 26 begin to melt so as to loosen and fall. The ice falls off the fingers 18 onto a rear sloping surface 23 of the tank or onto the sloping upper surface of the flap 17 and slides forward over the lower edge of the flap 17 into the storage compartment 2.

[0015] After a predetermined time delay sufficient to allow all the ice to fall off the fingers, the pump is started again to re-fill the tank and lift the flap 17. As this rises it releases the microswitch 41 to send the coolant fluid through the condenser again to cool the fingers.

[0016] As can be seen in Figures 3 and 4, the ice making tank 13 comprises side walls 24, upper and lower rear walls 25 and 30 joined by a sloping wall 23, upper and lower front walls 29 and 31 and a bottom wall 32. When the tank is filled, the flap 17 acts as part of the front wall. The flap 17 is shown in Fig.3 to be pivotally mounted on the lower front wall 31, but it could for example be mounted on the side walls 24. Rubber sealing strips 35 are provided inside the vertical edges of the aperture 28 against which the flap 17 abuts.

[0017] The flap 17 could be arranged to be moved by means other than water pressure or its own bouyancy for example by electromagnets arranged to operate in conjunction with the switching on and off of the pump 14 and the refrigeration circuit in timed system.

[0018] The device shown in the drawings would be particularly suitable as a small ice making machine for example in a bar. However, the invention could be applied equally well to larger scale machines, for example for use in industry or in laboratories.

Claims

1. An ice making machine comprising a water tank, at least one localised freezing surface in the water tank capable of generating a nodule of ice upon contact with water, means for cooling said freezing surface to a freezing temperature, means for filling the tank with water to a first level at which the freezing surface contacts the water and for lowering the level to a second level below any ice formed on the freezing surface, an ice storage receptacle accessible by hand, an openable closure on a side of the water tank and a movable guide surface interposable under the ice when the water is at the second level and the said closure is open to guide ice falling from the freezing surface to the receptacle through the closure, the machine being arranged to operate in successive freezing cycles with intermittent thawing periods during which the ice is guided to the receptacle.

2. An ice making machine according to claim 1 wherein the freezing surface comprises one or more fingers which can be cooled below 0°C.

3. An ice making machine according to claim 1 or claim 2 wherein the freezing surface is cooled by means of a fluid refrigerant.

4. An ice making machine according to any preceding claim wherein the guide surface also constitutes the closure.

5. An ice making machine according to claim 4 wherein the guide surface is a panel pivotally mounted along the bottom edge of the side opening in the tank and arranged to pivot between an upright position in which it closes the side opening and a sloping position in which it forms a chute for ice falling from the freezing surface.

6. An ice making machine according to claim 5 wherein the panel is arranged to be thrust upwardly by water entering the tank and held there by the pressure of the water.

7. An ice making machine according to claim 5 or claim 6 wherein the panel comprises a hollow body which is held by bouyancy in its upright position when the water is at the upper level but which falls under the influence of gravity to its sloping position when the water falls to its lower level.

8. A machine according to any preceding claim wherein the water is circulated into and out of the water tank by a pump.

9. An ice making machine according to any preceding claim which includes means for supplying heat to the freezing surface during the thawing period to release the ice therefrom.

10. An ice making machine according to any preceding claim which includes sensing means which detect the build up of ice on at least one freezing surface and respond to initiate a thawing period when the build up of ice has reached a predetermined level.

11. An ice making machine according to claim 10 wherein the sensing means comprises an electrical sensor positioned adjacent the freezing surface and means for detecting the electrical conductivity between the said sensor and another sensor positioned elsewhere in the tank, the said means being arranged, when the conductivity is altered by ice collecting on the sensor, to initiate the thawing period.

12. An ice making machine according to any preceding claim wherein the movement of the guide surface to its position below the freezing surface stops the cooling of the freezing surface to allow ice to form from the freezing surface.

13. An ice making machine according to any preceding claim wherein the thawing period is controlled by a time switch.

Drawing