| 摘要 |
A gate valve assembly having: a flowway; a cavity intersecting the flowway; a slab gate movable within the cavity between an open position, a closed position, and a relief position such that the open position allows fluid flow through the flowway, the closed position restricts fluid flow through the flowway, and the relief position allows fluid flow between the cavity and the flowway; a stem in mechanical communication with the slab gate so as to move the slab gate between the open position and the closed position; a retainer in mechanical communication with the slab gate so as to control movement of the slab gate between the closed position and the relief position, the retainer changing from a solid to one of a liquid or gas in the presence of heat; and a biaser of the slab gate toward the relief position.
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