GB557188A - Improvements in, or relating to, devices for controlling fluid pressures - Google Patents

Abstract

557,188. Relief valves. BELTON, C. M. D., and BOTT, H. May 12, 1942, No. 6396. [Class 135] A pressure relieving device comprises a main valve actuated by a diaphagm under the control of a diaphragm-actuated relay valve itself controlled by a presure-actuated weight-loaded control valve. The main valve 27 is formed with a pocket 36 adapted to receive a part-spherical head 35 on a spindle 34 secured to a diaphragm 8. This diaphragm is subject on one side to the pressure in the main inlet 9 and on the other side to the pressure in a chamber 7 connected to atmosphere through restricted passages 15 and to the main inlet through pipes 13, 14 controlled by the relay valve 24. This valve is guided by a spindle 40 with flats 43 engaging a bore 42 and is carried by a diaphragm 4 loaded by a dead weight 23. Fluid from the main inlet acts on the underside of the diaphragm and is supplied to a chamber 2 above the diaphragm through a pipe 11 fitted with a restriction 12 and is exhausted when the pressure is sufficient to lift a weightloaded valve 17, through passage 42 and atmosphere vents 19. The diaphragm is lifted to open the valve 24 and admit pressure to the chamber 7 either by a sudden increase of pressure below the diaphragm or by venting the chamber above. The admission of pressure to the chamber 7 balances the pressures acting on the diaphragm and permits conduit pressure to open the valve 27 and allow the escape of fluid to reduce the conduit pressure to the desired value. The valve 27 is loaded by a spring 28 bearing against a bridge 29 which also carries an adjustable stop 30 for limiting the lift of the valve.