Pressure relieving system

Claim 2

A pressure relieving system for a fluid pressure container comprising: a main relieving valve; said main valve having an inlet connected to the fluid pressure container to be protected, an outlet and pressure responsive means for controlling flow between said inlet and said outlet; a pilot valve; means supplying control pressure fluid to said pilot valve from said fluid pressure container; said pilot valve having an output of control pressure fluid (pressure) responsive to the pressure in said fluid pressure containers; a fluid flow switching device connected (to) between said pressure responsive means of said main valve and said outlet of said main valve and between said main valve pressure responsive means and said pilot valve control pressure fluid outlet to deliver the greater of fluid pressure to said pressure responsive means from said pilot valve output and from the outlet of said main valve; and said pilot valve being preset to relieve control pressure fluid from the pressure responsive means of said main valve when the container fluid pressure reaches a preselected desired maximum whereby the fluid pressure in said container is relieved

Claim 3

A pressure relieving system according to claim 1, including; a check valve in said pilot valve to prevent reverse flow of fluid through said pressure fluid supplying means.

Claim 4

A pressure relieving system for a fluid pressure container comprising; a main relieving valve; said main valve having an inlet connected to a fluid pressure container, an outlet and pressure responsive means for controlling flow between said inlet and said outlet; a pilot valve; means supplying control pressure fluid to said pilot valve from said fluid pressure container; said pilot valve having an output of control pressure fluid (pressure) responsive to the pressure in said fluid pressure container; means connecting said pilot valve to said pressure responsive means of said main Valve to control the flow through said main valve responsive to the control pressure fluid from (output of )said pilot valve; means connecting said outlet of said main valve to said pressure responsive means of said main valve whereby said main valve is held in closed position by fluid pressure in said outlet in excess of the fluid pressure at said inlet; a back flow preventer connected between said pressure responsive means and each of said pilot valve connecting means and said outlet connecting means; and said back flow preventer having a pressure responsive valve member being actuated to move responsive to the pressure in each of said connecting means to close communication between said pressure responsive means and the one of said connecting means having the lowest fluid pressure whereby said pressure responsive means is maintained in communication with the one of said connecting means having the highest fluid pressure.

Claim 5

A pressure relieving system for a fluid pressure container comprising; a main relieving valve; said main valve having an inlet connected to a fluid pressure container, an outlet and pressure responsive means for controlling flow between said inlet and said outlet; a pilot valve; means supplying control pressure fluid to said pilot valve from said fluid pressure container; said pilot valve having an output of control pressure fluid (pressure) responsive to the pressure in said fluid pressure container; means connecting said pilot valve to said pressure responsive means of said main Valve to control the flow through said main valve responsive to the control pressure fluid from (output of )said pilot valve; means connecting said outlet of said main valve to said pressure responsive means of said main valve whereby said main valve is held in closed position by fluid pressure in said outlet in excess of the fluid pressure at said inlet; a back flow preventer connected between said pressure responsive means and each of said pilot valve connecting means and said outlet connecting means; and said back flow preventer having a pressure responsive valve member being actuated to move responsive to the pressure in each of said connecting means to close communication between said pressure responsive means and the one of said connecting means having the lowest fluid pressure whereby said pressure responsive means is maintained in communication with the one of said connecting means having the highest fluid pressure.

Claim 6

A pressure relieving system for a fluid pressure container comprising: a main relieving valve; said main valve having an inlet connected to the fluid pressure container to be protected, an outlet and pressure responsive means for controlling flow between a said inlet and said outlet; (a pilot valve having an inlet valve and a vent valve, means supplying pressure fluid to said pilot valve from said fluid pressure container;) a pilot valve having an inlet, a control port, a vent outlet, a vent valve controlling flow from said control port to said vent outlet, and an inlet valve seating in response to flow from said inlet to said control port upon opening of said vent valve; means for supplying pressure fluid to said pilot valve inlet from said fluid pressure container; said pilot valve having (an) a control port output of fluid pressure responsive to the pressure in said fluid pressure container; said pilot valve also having a connection means for the connection of a test line therein; a valve connected to said pilot valve in said test line; a test pressure source; opening of said valve-delivering pressure fluid from said test pressure source to said pilot valve to test the setting of said vent valve; and said pilot valve inlet having a back flow valve seat coacting with said inlet valve whereby pressure fluid from said test pressure source is prevented from flowing through said supply means to said fluid pressure container.

Claim 7

A pressure relieving system for a fluid pressure container comprising: a main relieving valve; said main valve having an inlet connected to the fluid pressure container to be protected, an outlet and pressure responsive means for controlling flow between a said inlet and said outlet; (a pilot valve having an inlet valve and a vent valve, means supplying pressure fluid to said pilot valve from said fluid pressure container;) a pilot valve having an inlet, a control port, a vent outlet, a vent valve controlling flow from said control port to said vent outlet, and an inlet valve seating in response to flow from said inlet to said control port upon opening of said vent valve; means for supplying pressure fluid to said pilot valve inlet from said fluid pressure container; said pilot valve having (an) a control port output of fluid pressure responsive to the pressure in said fluid pressure container; said pilot valve also having a connection means for the connection of a test line therein; a valve connected to said pilot valve in said test line; a test pressure source; opening of said valve-delivering pressure fluid from said test pressure source to said pilot valve to test the setting of said vent valve; and said pilot valve inlet having a back flow valve seat coacting with said inlet valve whereby pressure fluid from said test pressure source is prevented from flowing through said supply means to said fluid pressure container.