GB628867A - A new or improved apparatus by which fluid supplied under pressure is controlled to impart a series of impulses - Google Patents

Abstract

628,867. Valves controlled by auxiliary valves. MACTAGGART, SCOTT, & CO., Ltd., and RUSSELL, R. C. April 14, 1947, No. 9851. [Class 135] An apparatus for imparting a series of impulses to fluid supplied under pressure comprises a control valve body a having ports c, f<SP>1</SP>, for connection to pressure and exhaust lines respectively, a main valve d controlling flow between the ports c, f, a spring-loaded pilot valve g within the main valve, having restricted passages h whereby pressure fluid entering at the port c and passing to an annulus b can act on the upper ends of both valves to maintain them closed. A pilot valve actuating-device consists of a stem p<SP>1</SP> interconnected by a spring q with a cylindrical member c itself loaded by a spring p and actuated by a ram m<SP>1</SP> connected by a conduit l with the low-pressure side of a relief valve i loaded by an adjustable spring j and whose inlet is connected by conduits i<SP>1</SP>, i<SP>2</SP> with the annulus b. Also connected with the low-pressure side of the relief valve is a valve body s having a ball-valve s<SP>2</SP> acted upon by a plunger s<SP>1</SP> subject to the pressure in the conduit i<SP>1</SP>, the valve s<SP>2</SP>, when open, permitting the escape of fluid from the ram cylinder, through an adjustable throttle t and a conduit t<SP>1</SP> to the exhaust line. In operation, fluid pressure builds up in the port c and in the conduits i<SP>1</SP>, i<SP>2</SP> until it overcomes the loading of the relief valve i and passes to the ram, the valve s<SP>2</SP> being held in its closed position by pressure on the plunger s<SP>1</SP>. The ram raises the member o, compressing both the springs p, q, until a rod r carried by the member o engages the stem p<SP>1</SP>, which then opens the pilot valve, the spring q extending as the pilot valve is opened, to cause full opening thereof. The release of pressure above the main valve caused by the opening of the pilot valve allows the former to be opened by the pressure in the annulus b, thereby placing the port c in communication with the exhaust and causing a fall in the pressure supplied to the control valve. This fall in pressure allows the valve i to close and the valve s<SP>2</SP> to open and exhaust the ram at a rate determined by the setting of the throttle t, the pilot and main valves then closing and the cycle being repeated.