Patent GB-731042-A (GB)
Title: Improved freezing apparatus for making ice blocks
IPC: F25C1/06
Filed: 1953-09-18
Abstract: 731,042. Ice-making. GRASSO'S MACHINEFABRIEKEN N. V. Sept. 18, 1953 [Oct. 7, 1952], No. 25870/53. Class 29. An ice-mould 1 having an evaporator jacket 15 is closed at its upper end and dips into a water tank 2, the water being drawn into the mould by suction applied through a pipe 7. Beneath the jacket 15 is an annulas of heat insulation 49 or a heated jacket to prevent the formation of ice' in the bottom of the mould. The water may be precooled in tank 2 by an evaporator coil. Refrigerant circuit. Refrigerant from the compressor 17 passes through pipe 19 to the condenser 20 and then through a pipe 21 to a coil 22 located in a separator 23 so that the refrigerant is precooled. It then passes through expansion valve 25, which may be actuated by a float responsive to the liquid level in the separator, and a pipe 26 to an evaporator 16 extending down the centre of the mould. Mixed liquid and vapour from the evaporator 16 passes through pipe 29 to the separator 23. Liquid refrigerant flows from the separator to evaporator 15 through pipe 27, the vapour returning through pipe 28. The separator is connected to the compressor suction through a pipe 18.  Ice-freeing. When freezing is complete, expansion valve 25 and a valve 30 in suction pipe 18 are closed and valves 31, 36 respectively in pipes 32, 24 are opened. Hot gas then passes from the compressor exhaust through valve 31 to the separator and to the evaporators. The increase in'pressure forces liquid refrigerant in evaporator 16 back through pipe 26 and valve 36 to pipe 27 leading to storage vessel 33. Refrigerant is also forced from separator 23 and evaporator 15 into pipe 27 and the storage vessel. When the ice-bond has been broken, the block drops into the tank 2 into a gripping device which is then manipulated from above to remove the block. The block has a central vesting the water freezing due to the block being aperture which is filled with water after harsupercooled. Air-circuits. Suction pipe 7 is connected through a valve 11 and a reservoir 8 to an exhauster 9 discharging into a second reservoir 40 from which compressed air passes through pipe 46 to a nozzle 48 which bubbles air up through. the mould to ensure the formation of clear ice The degree of vacuum and pressure can be regulated by valves 10, 41 in reservoirs 8, 40. When harvesting is required, a valve 47 in pipe 46 and the valve 11 are closed and a valve 43 in a pipe 42 is opened to admit pressure air from reservoir 40 to the top of the mould. Alternatively a valve 44 may be opened to vent the top of the mould to atmosphere through a pipe 45. Modifications. The suction pipe 7 may be connected directly to the exhauster 9 and, instead of entering the mould, enters a chamber communicating by a stand pipe with the tank 2 and with the mould top by a pipe above the desired liquid level. A float is responsive to the liquid level in the chamber to close the pipe 7 when the liquid reaches the desired level. In another form, the exhauster 9 is replaced by a self-priming rotary pump and the open end of pipe 7 is disposed at the desired liquid level. This arrangement provides a continuous flow of water upwardly in the mould to assist the formation of clear ice. Specification 662,415 is referred to.