| 摘要 |
A valve shutoff mechanism for automatically operating a gas valve, a liquid valve or the like to shut off the flow of fluid in a pipeline in response to an earthquake, temperature changes and/or an electrical or mechanical signal generated by an associated mechanism. The housing, formed of complementary, symmetric half portions, encloses a spring bias motor, a torque arm assembly coupled to the spring motor for rotation about a first axis, a latch assembly for normally preventing rotation of the torque arm assembly, and a triggerable catch assembly for normally maintaining the latch assembly in contact with the torque arm assembly and for enabling the latch assembly to disengage the torque arm assembly in response to seismic vibrations of predetermined magnitude and acceleration, an externally generated electrical signal, temperature changes of predetermined magnitude or a combination thereof. The triggerable catch means includes a triggering device for releasing the latch assembly which in turn releases the torque arm assembly for rotation, the trigger device comprising a ball weight connected to or supported by the free end of the trigger arm, a compression spring bearing on the free end of the trigger arm, an electrically operable solenoid coupled to the trigger arm, a temperature sensitive switch element coupled to the trigger arm or combination thereof.
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