摘要 |
Fluid pressure above a predetermined limit in a fluid pressure system is reduced by operating a relief valve, having its inlet port connected with the system, in a throttling action. A normally seated valve member is maintained in relief valve closed position by pneumatic pressure on a piston in a chamber of the relief valve. A fluid pressure sensor communicating with the inlet port generates a signal in response to fluid pressure above a predetermined limit received by a sensor signal processor energized by a source of electrical energy which releases pneumatic pressure in the chamber for a predetermined time interval allowing system fluid pressure to unseat the valve member and exhaust fluid pressure through the relief valve outlet port.
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