Patent GB-245124-A (GB)
Title: Improvements in evaporators for refrigerating apparatus
IPC: F25B17/00
Filed: 1925-12-19
Abstract: 245,124. Otto, S., (Assignee of Jankus, J. C.). Dec. 19, 1924, [Convention date]. Refrigerating, absorption machines for. - The. evaporator of a machine working on the reversing system, particularly one for domestic use, is provided with a sump in which absorbent liquid carried over during the generating period is collected and from which the liquid is returned automatically to the generator-absorber at the beginning of each absorption period. The evaporator preferably comprises an upper header or chamber 10 containing an open cup-shaped vessel 12, a series of upright tubes 15, or a sinuous tube, and a lower header 18 in open communication with the annular jacket 16 of a freezing-chamber 17 set at right angles to the general plane of the evaporator. The sump 14 in which the absorbent liquid is collected is arranged below the jacket 16 and communicates therewith through a fine opening 19, which may be provided in a removable plug. A draining plug 30 is provided in the sump. The liquefied refrigerant is delivered from the condenser through a pipe 25 leading to the bottom of the cup 12, and overflows the cup or passes' through an aperture 26 therein into the top header 10, the tubes 15 and lower header. The cup is supported by a tube 23 opening at its lower and into the upper part of the jacket 16 but closed at its upper end and provided with an opening 24 to the header 10 some distance below its end. A fine tube 21 extends through the tube 23 from the bottom of the sump to the interior of the cup 12, with which it communicates through a small opening 22. The upper part of the sump communicates by a tube 20 with a closed chamber 11, which may be separate from or form one end closure of the header 10. During the generation-condensation period the whole of the evaporator may become substantially filled with liquefied refrigerant, and any absorbent liquid carried over sinks into the sump 14 and rises up the tube 20. At the beginning of the absorption-evaporation period the vapour pressure in the closed chamber 11 becomes superior to that in the header 10 and forces the absorbent liquid up the fine tube 21 to the cup 12, from which it is sucked back through the pipe 25 into the generator-absorber. As soon as the pressures in the chamber 11 and evaporator are equalized, the return of absorbent will be stopped, and only vapour arising from normal evaporation during the cooling period will flow through the pipe 25 back to the generator-absorber. Any vapour arising from ebullition in the large tube 23 will pass into the header 10. while the contents of the fine tube 21 will thereby be kept sufficiently cool to prevent evaporation. The evaporator may be used with a machine such as is shown in Fig. 6. comprising a generator-absorber vessel 36 divided by a partition 38 into vapour and liquor chambers. The vessel may be heated by an annular burner 41 and cooled by a coil 42. A rectifier 45 is provided between the vapour space of the generator and the main part 44 of the double-tube condenser, the condensed absorbent being returned from the rectifier to the generator by a pipe 48. A separate pressure pipe 34, Fig. 1, may be used to connect the condenser outlet with the bottom of the evaporator, the pipe 25 then serving solely as the return or suction pipe. Where a single pressure and return pipe 25 is employed, the pipe 34 may be used for the occasional return of liquid from the evaporator, for instance after the apparatus has been accidentally inverted during shipment &c. In such a case the pipe 34 is connected to a three-way cock on the generator side of the condenser, so that the passage to the condenser may be closed and the pressure in the evaporator may be utilized to force all of the liquid back through the pipe 34 into the generator absorber. Refrigerators, domestic and like.-The evaporator may be placed flat against the back of a refrigerating chamber, with the open end of the freezing chamber 17 projecting forwards. Upper and lower doors are fitted to the chamber.