Pressure control system

Claim 2

A pressure control system for a fluid system under pressure comprising a pressure responsive pilot valve, means connecting the pilot valve to a fluid system to be controlled for delivering fluid under pressure from said fluid system to said pilot valve, said pilot valve including means for presetting a preselected pressure condition at which said pilot valve responds by discharging said fluid under pressure, an activator, a control valve, said activator being mechanically interconnected to said control valve and being responsive to fluid pressures, means connecting said pilot valve to said activator to supply and vent said fluid under pressure discharged therefrom to said activator, a safety device having a pressure responsive actuator, means supplying actuating fluid under pressure to said control valve, means connecting said control valve to said safety device actuator to control the delivery of actuating fluid to said safety device actuator whereby on occurrence of said preselected pressure condition in said fluid system said safety device is actuated to control pressure in said fluid system, said activator including a body defining a central bore and end bores of reduced diameter communicating with said central bore, a piston movably positioned within said bores, and means providing communication into said central bore on opposite sides of said piston, said piston including a connecting rod extending through one of said end bores and adapted to connect to said control valve, said piston havIng three effective pressure areas with two of said areas being opposed to the third of said areas, the effective pressure areas on said piston urging said piston towards shutdown direction being greater than the effective pressure areas on said piston urging said piston in the opposite direction.

Claim 3

A pressure control system according to claim 1 wherein said safety device is a shut-down valve connected to said fluid system whereby actuation thereof causes said fluid system to be shut down.

Claim 4

A pressure control system according to claim 1 wherein said pilot valve is connected to said activator to reset said activator and said control valve responsive to fluid system pressures returning to normal.

Claim 5

A pressure control system according to claim 1, wherein said activator and said control valve are only reset manually.

Claim 6

A pressure control system for a fluid system under pressure comprising a pressure responsive pilot valve, means connecting the pilot valve to a fluid system to be controlled for delivering fluid under pressure from said fluid system to said pilot valve, said pilot valve including means for presetting a preselected pressure condition at which said pilot valve responds by discharging said fluid under pressure, an activator, a control valve, said activator being mechanically interconnected to said control valve and being responsive to fluid pressures, means connecting said pilot valve to said activator to supply and vent said fluid under pressure discharged therefrom to said activator, a safety device having a pressure responsive actuator, means supplying actuating fluid under pressure to said control valve, means connecting said control valve to said safety device actuator to control the delivery of actuating fluid to said safety device actuator whereby on occurrence of said preselected pressure condition in said fluid system said safety device is actuated to control pressure in said fluid system, said activator including a body defining a central bore and end bores of reduced diameter communicating with said central bore, a piston movably positioned within said bores, and means providing communication into said central bore on opposite sides of said piston, said piston including a connecting rod extending through one of said end bores and adapted to connect to said control valve, said piston having an effective pressure area in the other of said end bores smaller than its effective pressure areas in said central bore, the effective pressure areas of said piston in said central bore being equal.

Claim 7

A pressure control system for a fluid system under pressure comprising a pressure responsive pilot valve, means connecting the pilot valve to a fluid system to be controlled for delivering fluid under pressure from said fluid system to said pilot valve, said pilot valve including means for presetting a preselected pressure condition at which said pilot valve responds by discharging said fluid under pressure, an activator, a control valve, said activator being mechanically interconnected to said control valve and being responsive to fluid pressures, means connecting said pilot valve to said activator to supply and vent said fluid under pressure discharged therefrom to said activator, a safety device having a pressure responsive actuator, means supplying actuating fluid under pressure to said control valve, means connecting said control valve to said safety device actuator to control the delivery of actuating fluid to said safety device actuator whereby on occurrence of said preselected pressure condition in said fluid system said safety device is actuated to control pressure in said fluid system, said activator including a body defining a central bore and end bores of reduced diameter communicating with said central bore, a piston movably positioned within said bores, and means providing communication into said central bore on opposite sides of said piston, said piston including a connecting rod extending through one of said end bores and adapted to connect to said control valve, said piston having an effective pressure area in the other of said end bores smaller than its effective pressure areas in said central bore, the effective pressure areas of said piston in said central bore being equal.

Claim 8

A pressure control system according to claim 5, including an override passage defined in said activator body in communication with the central bore of said body, an override piston positioned within said override passage and adapted to engage said activator piston to retain said piston in normal position, means exposing the side of said override piston away from said activator piston to the venting through said pilot to activate said override piston out of engagement with said activator piston responsive to a pressure differential when said pilot senses and responds to the preselected pressure condition, and means on the exterior of said activator body for directly moving said override piston into engagement with said activator piston.

Claim 9

A pressure control system for a fluid system under pressure comprising a pilot valve having a pair of control pressure connections, a supply pressure connection and a vent, means for connecting said pilot valve to a fluid system to be controlled for delivering fluid under pressure from said fluid system to said pilot valve, said pilot valve being responsive to a preselected high pressure and a preselected low pressure in said fluid system to provide a control pressure of said fluid under pressure at one of said control pressure connections with fluid pressuRe within said fluid system between said preselected limits, said pilot valve venting control pressure from said one of control pressure connections with fluid pressure within said fluid system being outside one of said preselected limits and said pilot valve supplying control pressure to the other of said control pressure connections with fluid pressure within said system being outside the other of said preselected limits, a control valve, an activator mechanically connected to operate said control valve and being responsive to fluid pressures, a shutdown valve connected to said fluid system, means supplying actuating fluid to said control valve, means for connecting the control pressure connections of said pilot valve to said activator to bias said activator toward normal position responsive to normal fluid pressure within said fluid system, the venting of one of said control pressure connections and pressurizing the other of such control pressure connections resulting in actuation of said activator to move said control valve to shutdown position, means connecting said control valve to said shutdown valve to deliver said actuating fluid to said shutdown valve with the control valve in shutdown position, said activator including a body defining a central bore and end bores of reduced diameter communicating with said central bore, a piston movably positioned within said bores, and means providing communication into said central bore on opposite sides of said piston, said piston including a connecting rod extending through one of said end bores and adapted to connect to said control valve, said piston having an effective pressure area in the other of said end bores smaller than its effective pressure areas in said central bore, the effective pressure areas of said piston in said central bore being equal.

Claim 10

A pressure control system for a fluid system under pressure comprising a pilot valve having a pair of control pressure connections, a supply pressure connection and a vent, means for connecting said pilot valve to a fluid system to be controlled for delivering fluid under pressure from said fluid system to said pilot valve, said pilot valve being responsive to a preselected high pressure and a preselected low pressure in said fluid system to provide a control pressure of said fluid under pressure at one of said control pressure connections with fluid pressuRe within said fluid system between said preselected limits, said pilot valve venting control pressure from said one of control pressure connections with fluid pressure within said fluid system being outside one of said preselected limits and said pilot valve supplying control pressure to the other of said control pressure connections with fluid pressure within said system being outside the other of said preselected limits, a control valve, an activator mechanically connected to operate said control valve and being responsive to fluid pressures, a shutdown valve connected to said fluid system, means supplying actuating fluid to said control valve, means for connecting the control pressure connections of said pilot valve to said activator to bias said activator toward normal position responsive to normal fluid pressure within said fluid system, the venting of one of said control pressure connections and pressurizing the other of such control pressure connections resulting in actuation of said activator to move said control valve to shutdown position, means connecting said control valve to said shutdown valve to deliver said actuating fluid to said shutdown valve with the control valve in shutdown position, said activator including a body defining a central bore and end bores of reduced diameter communicating with said central bore, a piston movably positioned within said bores, and means providing communication into said central bore on opposite sides of said piston, said piston including a connecting rod extending through one of said end bores and adapted to connect to said control valve, said piston having an effective pressure area in the other of said end bores smaller than its effective pressure areas in said central bore, the effective pressure areas of said piston in said central bore being equal.