GB442775A - Improvements in or relating to air pumps, superchargers and the like - Google Patents

Abstract

442,775. Air compressors; superchargers ; valves. AMERY, G., 3, Greville Road, Kilburn, London. June 13, 1934, Nos. 17498 /34 and 13533/35. [Class 8 (i)] [See also Groups XXVII and XXIX] In arrangements for compressing gaseous fluids to a desired pressure independently of variations of the supply pressure of the fluids so that, for example air can be supplied to an aeroplane engine at normal atmospheric pressure, the receiver supplying air to the compressor or to the cylinders of the engine is regulated by a relief valve which is controlled by the pressure of gaseous fluid in a chamber maintained at a constant temperature by an automatic temperature-responsive device. In Fig. 1 which shows a twostage compressor with first-stage double acting pistons on the left-hand side, air entering the inlet 37 compressed during the inward stroke of the piston is supplied past the spring- loaded valve 36 to the receiver 34 which is controlled by the automatic valve to be subsequently described. During the inward stroke of the piston, air is also drawn through the main inlet 30 controlled by the valve 31. Should the charge above the piston be at less than atmospheric pressure, the deficiency is made up from the receiver 34 through the inlet 38 which opens to the cylinder at the end of the inward stroke of the piston. The charge compressed during the outward stroke passes the delivery valve 33 into the second stage of the compressor. The automatic relief valve 40, Fig. 2, by means of which the fluid in the receiver 34 is maintained at constant pressure is in communication with a chamber 54 containing a quantity of gas which is maintained at a constant temperature by fluid circulated through the pipe 55. Should the pressure in the receiver 34 rise above normal atmospheric, the valve opens and the excess is discharged through the vent 53. The arrangement for maintaining constant temperature in the chamber 54 is shown in Fig. 4 and comprises a bi-metallic strip 86 linked up to the butterfly valve 82 which controls the supply of heating-fluid passing through the pipe 55. In a modification, increase of temperature in the chamber causes displacement of a pressuresensitive element and consequent control of supply of the heating medium. In a further modification the valve 63, Fig. 3, controlling the receiver 60 has a piston 67 opening into the chamber 68 and a shoulder 70, exposed to atmosphere through the duct 71. The space 72 beneath the shoulder is connected to vacuum through the pipe 73. In this case, the lower the atmospheric pressure, the higher will be the pressure maintained in the receiver 60. The air from the receiver 60 may be supplied directly to the cylinders of an internal-combustion engine. Specifications 14695/15,106,635, and 128,668, [all in Class 7 (iii)], are referred to.