| 摘要 |
An elastomeric sleeve is placed under axial compression in a pinch valve assembly. The axial compression of the sleeve eliminates any crevices with end members that engage opposed end walls of the valve body. Further, axial compression extends cycle life of the valve by maintaining the sleeve in a non-tensile relationship. Mechanical gripping of enlarged flanges defined at opposed ends of the sleeve is also enhanced through axial compression of the sleeve. A positive, visual indication of valve open and closed positions is provided by an indicator stem extending outwardly from an actuator body. In an alternate embodiment, the flanges are reinforced. Additionally, a casing member is interposed between the valve body and sleeve for ease of replacement and maintenance. In still another embodiment, a vent opening in the valve body eliminates pneumatic closure forces on the elastomeric sleeve that can arise when the pinch valve is heated. The vent opening can also be connected to a valve to provide selective venting of the valve body.
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