| 摘要 |
There is disclosed a gate valve having a cast body which is of sufficiently low height that the upper end of the gate remains partially within a cavity in the bonnet connected to the body as it moves between opened and closed positions. Guide surfaces are formed in the open end of the bonnet cavity for guiding the side edges of the gate as it is so moved. The stem is of a non-rising type having a ring mounted for rotation without reciprocation between upper and lower axial thrust bearings in the bonnet and connected to a one-piece stem by means of a pin which is adapted to shear in response to a predictable axial load on the stem.
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