| 摘要 |
875,174. Fluid-pressure servomotor control systems. GRATZMULLER, J. L. Dec. 17, 1958 [Dec. 18,1957; Dec. 2,1958], No. 40703/58. Class 135. A pressure fluid control maintaining the pressure in a chamber 4 within a narrow range, for operating pneumatic circuit breakers, comprises a high flow-rate valve 8 between the pressure source 7 and the chamber, and a system compensating small chamber pressure variations -e.g. due to leakage and temperature fluctuation-including a low flow-rate inlet valve 9 and an outlet 12 controlled by a valve 11 for keeping the chamber pressure below the upper limit, and means 20 responsive to chamber pressure to open the low-rate valve when chamber pressure falls to a predetermined value superior to the lower limit and to open the highrate valve when chamber pressure falls to the lower limit. Chamber pressure increase is detected via pipe 21 by spring-loaded diaphragm 25 to raise plunger 22 and tilt a triangular plate 32 whereby firstly a switch 1 breaks to deenergize an inhibition device 17 which then allows the circuit breaker to be operated and to close solenoid supply valve 13 and open an exhaust valve 43 whereby diaphragm 48 moves down and allows inlet pressure to close the highrate valve. Fluid continues to be supplied to the chamber through the low rate valve and check valve 18, which prevents reverse flow and chamber pressure leakage past the low-rate solenoid valve actuating-stem 40. As chamber pressure reaches its upper limit, switch 2 is broken to close the low-rate valve. Should the chamber pressure go above the upper limit, switch 3 makes and opens low-rate solenoid exhaust valve 11. Relief valve 19 opens if the chamber pressure continues to rise. In an alternative embodiment the two closures of valve 13 are separately operated by solenoids in parallel, one closure being a loose ball, and check valve 18 is opened by a solenoid in parallel with that of valve 9. The switches are operated in reverse order if the chamber pressure falls. |
