GB579473A - Improvements relating to fluid pressure power supply systems - Google Patents

Abstract

579,473. Pneumatic power transmission. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd. (Bendix-Westinghouse Automotive Air Brake Co.). April 20, 1944, No. 7321. [Class 8 (ii)] A compressor 10 initially charges the high and low pressure reservoirs of a pneumatic circuit in parallel till a certain pressure is reached; the compressor normally forms part of the closed circuit; automatic pressure regulating means are provided. Fig. 1 shows a circuit including low- and high-pressure reservoirs 6, 7 initially charged in parallel by the compressor delivering through a pipe 15 and a control valve 17, and a pipe 18 with a check valve, and drawing from atmosphere through a check valve 13. The valve mechanism 17 comprises diaphragms which respectively carry the stem of a valve 26 and a rod 39; the reservoirs are each connected with one side of the diaphragm by pipes such as pipe 44 having valve 42 which opens pipe 44 to atmosphere so long as pressure in reservoir 6 is less than a set value. At filling below this pressure reservoir 6 is supplied through the open lower valve seat until its pressure acts on the diaphragm causing the valve 26 to close this seat and open the upper seat through which the reservoir pressure feeds the compressor to feed the highpressure reservoir. The pressure in reservoir 6 thus falls again reversing valve 26 causing the compressor to draw again from atmosphere to fill the reservoirs. This continues till pressure in high-pressure reservoir 7 acts on the lower diaphragm to cause its rod to hold the valve off the lower seat, the compressor then circulating air idly. Fall of pressure due to leakage in either reservoir automatically actuates the valve mechanism to restore the pressure. The system operates a brake, the cylinder 48 of which is connected to a valve device 51 actuated by a lever so that the brake may be actuated by air from the high-pressure reservoir 6 and may exhaust into the low-pressure reservoir. In another form the rod 39 and the high-pressure diaphragm and its associated valve 42 are omitted; the highpressure reservoir is connected with the lowpressure reservoir through a pipe which joins the exhaust pipe from the brake valve and contains air adjustable relief valve permitting flow of air between the reservoirs only when their pressure difference is sufficient.