Importance

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Abstract

A control-reliable lockout valve system has an inlet port for coupling to a source of pressurized fluid and an outlet port for coupling to a downstream fluid-actuated device. A double valve unit includes a pair of valve elements each controllably moving between a respective actuated position and a deactuated position to control a first flow path between the inlet port and the outlet port in response to a pilot pressure applied to the valve elements. The first flow path provides the pressurized fluid to the outlet port only if both of the valve elements are in the respective actuated positions. The double valve unit further includes an exhaust port, and the valve elements control a second flow path for coupling the outlet port to the exhaust port unless both of the valve elements are in the respective actuated positions. A pilot supply valve is provided having an inlet for coupling to the source of pressurized fluid, an outlet coupled to the double valve unit, and a manually actuated valve element for selectably applying the pilot pressure to the valve elements of the double valve unit, whereby the manually actuated valve element can be closed to isolate the valve elements of the double valve unit from the pilot pressure to lockout the valve system in a control-reliable manner.

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First Claim