| 摘要 |
1,089,641. Fluid-pressure servomotor systems. C.A. PARSONS & CO. Ltd. May 24, 1965 [June 5, 1964], No.23494/64. Heading G3P. The stop valve of a steam turbine is actuated by hydraulic pressure controlled by a speed governor valve 4 while valves 6, 7 responding to changes in condenser and stop valve pressure, respectively, automatically adjust the governor setting to correspond to reductions in turbine load. The pressure controlled by the valve 4 acts on the stop valve and on one side of a differential pressure gauge 26 in parallel with a non-return valve 29, the other side of the gauge and valve being subjected to the pressure controlled by the valves 6 and 7. The gauge controls a switch 27 for resetting the governor motor which due to the valve 29 maintaining a pressure differential, remains at the reduced load setting after the valves 6 and 7 have returned to their original positions, the governor being reset manually to restore the load on the turbine. Actuating pressure for the valve 7 is obtained from a point between a pair of orifice plates in the steam line while the valve 6 incorporates a valve which closes the connection to drain when the hydraulic pressure falls to a predetermined minimum value. In a modified system the governor valve controls a fire-resistant fluid which in turn controls the fluid for actuating the stop valve through a relay (34 Fig. 2, not shown), the relay containing two pairs of opposed bellows for actuating the relay valve (39) and a valve (45) providing accelerated response to rapid falls in governor controlled pressure |
