| 摘要 |
A tripping control system for e.g. turbines includes a block circuit A having two or more blocking valves 440, 470 in series for blocking a pressure supply line 150a-150b with redundancy and a bleed circuit B having pairs of series mounted bleed valves 230,280 240,260 250, 270 connected in parallel between the supply line and a return line to bleed pressure from the supply line. The bleed valves are operated in non-series pairs by control valves 292-294 to provide voting redundancy under control of a safety controller which initiates a trip by performing a bleed function which causes the block function to operate. Pressure sensors 300, 310, 320, 480 provide feedback and allow the controller to test the valves which are connected such that any one parallel pair can be tested without causing a turbine trip and without preventing the turbine from being tripped.
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