| 摘要 |
<p>892,729. Hydraulic turbines. ALLIS-CHALMERS MANUFACTURING CO. May 20, 1960, No. 17972/60. Class 110 (3). [Also in Group XXIX] An hydraulic turbine having blades 8 adjustable by a fluid-pressure servomotor 12 under the control of a valve 56 which is actuated by a turbine-driven governor 38 so that the pitch of the blades is decreased as the speed increases and vice versa has an overspeed governor 90 operating a valve 96 which controls an intercept valve 66 in the conduits 52, 54 between the valve 56 and the servomotor whereby on overspeeding of the turbine, resulting in venting of a chamber 80 and consequent downward movement of the intercept valve member, the portions 52b, 54b of the conduits 52, 54 are interconnected with each other to equalize the pressures on the two sides of the servomotor piston so that the blades, which are so arranged that the water pressure constantly urges them towards their coarse pitch positions, take up these positions in which the runaway speed is lowest. Under overspeed conditions the control valve 56 will be in its lowest position so that servo fluid from an inlet 50 will be acting through the conduit 52 on differential areas 68, 70 of the intercept valve to assist a spring 86 in lowering the intercept valve member. At the same time the conduit 54 will be vented to an outlet 62 so that the interconnected conduit portions 52b, 54b are also vented through the conduit 54. The valve 96, which is continuously rotated to ensure freedom of operation, is adjustably loaded by a spring 150. A follow-up arrangement is stated to be provided between the blades and the control valve 56.</p> |
