| 摘要 |
A diagnostic system comprises a displacement transducer and means to connect this to a valve to measure its displacement, means to select and apply a pre-determined pressure to a valve or means to detect a pressure resulting from the valve's operation and means, for example a PC, to receive and record valve displacement as a function of pressure applied or resultant. The system may be used with apparatus comprising three solenoid operated valves, the outlet of a first on/off valve 76 being connected to the inlet of a second on/off valve 80 and to the inlet of a third, flow-control needle valve 82. The outlet from the valve 80 is connected to atmosphere, while the outlet from the needle valve leads to an outlet 77 for connection to the equipment under test. The valve member of the needle valve 82 may be set in an open, closed or any intermediate position, this position being sensed by a position transducer. Displacement transducers sense slamshut valve and regulator displacements within the equipment, while a pressure transducer and a differential pressure transducer are each connected to the equipment. The apparatus may include further solenoid operated valves in the form of an on/off ball valve 86 and a second on/off venting valve 90 arranged in parallel with the valves 76,80,82.
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