| 摘要 |
A fluid pressure actuated valve wherein a relatively low powered analog electrical signal accurately controls the position of the output member of a fluid pressure powered actuator which in turn can be used to exert mechanical forces or operate mechanical devices such as fluid pumps, motors or valves. Inlet and outlet passages communicate a pressure chamber to high and low pressures respectively. A control element totally within the chamber so as to have balanced pressure forces thereon and made of a magnetically sensitive material is moved to a fixed position in the chamber proportional to the strength of an externally generated magnetic field. At least one of the passages moves with the output member so as to be opened or closed by the control element relative to the other passage. The output member follows the control element automatically varying the pressure in the chamber to compensate for any variations in the external forces thereon. The output member includes a rod like element having a port in its side for one of the passages and the control element is a sleeve surrounding the rod and can be moved by any externally controlled means including the magnetic field or an external mechanical interconnection, various internal friction reducing arrangements are provided.
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