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Bellows sealed plug valve

A bellows sealed plug valve includes a valve body having an inlet passage and an outlet passage, a valve chamber between the inlet and outlet passages. A valve plug has substantially the same shape as the valve chamber and is rotatably disposed therein. A shaft is movable linearly in response to a signal from a valve actuator. A bellows is sealingly disposed between the valve chamber and the valve actuator and means are located between the bellows and the valve plug for converting linear movement of the shaft connected to the valve actuator to rotational movement of the plug. Various means are disclosed including helical thread mechanism, clevis mechanism and rack and pinion mechanism, all for converting linear motion to rotational motion. An improved 1/4 turn operator valve including a valve body having an inlet passage and an outlet passage, a valve chamber between said inlet and outlet passages, a valve plug having substantially the same shape as said valve chamber and being rotatably disposed therein, said valve plug having a flow passage disposed therethrough, said flow passage disposed such that with said valve plug in a first position said flow passage is in alignment with said inlet and said outlet passages and provides fluid communication therebetween, and with said valve plug in a second position said flow passage is out of alignment with said inlet and outlet passages and said valve plug interrupts fluid communication therebetween, a shaft connected to a valve actuator movable linearly in response to a signal from said valve actuator, wherein the improvement comprises: a cap assembly, an actuator shaft passing through said cap assembly, a secondary sealing member encircling said actuator shaft, a collar assembly in contact with said actuator shaft and responsive to linear motion of said actuator shaft, an operator shaft adapted to receive a torsional force from said collar assembly, a bellows cooperating with said collar assembly and said cap assembly to form a primary sealing assembly isolating said valve chamber from said actuator shaft to prevent fluids from passing between said collar assembly and said bellows, a valve plug connected to said operator shaft and a return position spring encircling said operator shaft; said collar assembly includes a cylindrical member encircling said operator shaft and a flange member attached to said cylindrical member and said bellows, and wherein said torsional force is provided by helical threads on said cylindrical member and said operator shaft causing rotation of said valve plug upon linear reciprocal movement of said actuator shaft; and wherein said cap assembly includes sealing flange, and sealing means thereby effecting a fluid tight seal between said valve body and said sealing flange.

                                                                                            Shanghai Remy Valve Manufacturing Co., Ltd

2012-01-09 06:20

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