Patent GB-185607-A (GB)
Title: Process and machine for refrigeration
IPC: F25C1/16
Filed: 1921-08-11
Abstract: 185,607. Stewart, W. Aug. 11, 1921. Paraffin wax, extracting.-A process for icemaking or precipitating solids from liquids, such as paraffin from oil, by freezing, consists in spraying the liquid upwardly on to the walls of an open-bottom mould or container surrounded by a refrigerant, the interior of the container being actuated by a steam-ejector or other vacuumproducing means. The vapour from the spray may be congealed on cooling surfaces, and the ejector may discharge into a jet condenser to obtain a high vacuum. The apparatus described comprises a series of conical moulds 3 arranged in a. closed vacuum-jacketed refrigerating tank 5 and a movable table or platform 24 formed with a water chamber communicating with spray nozzles 60 projecting up into the moulds. When the moulds are full of ice a thawing-medium is circulated around them to free the ice, and the table is lowered by screw and nut gearing 37, 38 to remove the blocks. The refrigerant is circulated bv an impeller 6 driven from a bevel wheel 13 at the top of the apparatus, and after passing around the moulds is circulated through coils 100 upon which the vapour from the spray congeals. The congealed matter is continuously removed by spraying the coils with the liquid to be frozen, which is led from the chamber in the table through a telescopic pipe 58 to spraying devices 110. A pump 50 in a chamber carried by the table draws the liquid from a supply pipe 59 and from an overflow chamber below the nozzles and forces it into the chamber supplying the nozzles. The table is mounted on springs around the screws 37 to avoid shock when it is raised into operative position, and an airtight joint with the wall 23 of the tank is formed by a pneumatic tube 27. Fig. 8, forcing a ring 26 into contact with the table, and a liquid seal 30. The upper ends of the moulds are fitted with baffles 98, and, to equalize the pressure, the upper and lower parts of the casing communicate through passages 92 located between the moulds and through external valved pipes 93. The vacuum jacket communicates with the casing by a pipe 96 and is ex. hausted by the means employed to create the vacuum in the tank, which may be a steamoperated ejector 121. The moulds have external angularly disposed corrugations 3<1>, Fig. 4, to deflect air bubbles and to give a continuous flow to the refrigerant. The spraying nozzles, Fig. 5, are carried by tubes 62 from the top plate 21 of the table, and comprise a grooved member 65, and a screw-adjusted valve member 69, the stem 70 of which is carried through a stuffing-box 73 to a hand-wheel. The setting of the valve is indicated by a pointer 78 on a bracket 77. A rod 81 is carried through the nozzle and may be manipulated by a handle 83 at the bottom to ascertain the thickness of the ice formed. A series of smaller spray nozzles 111 are provided to increase the cooling by evaporation at the beginning of the operation. In the fractional freezing of oils &c., the coils 100 serve for freezing out the water, the wax is deposited in the moulds, and the more volatile products are carried off by a vacuum pump.