| 摘要 |
A packingless gate valve is disclosed which includes a housing (11) having opposed similar housing halves (30,32) with primary resilient sleeve units (53,54) which compressibly engage each other in the valve open condition and engage opposite sides of the gate in the valve closed condition. A secondary resilient seal unit (80) is positioned above the primary sleeve units (53,54) within the housing (11) and is secured between the housing halves (30,32). The secondary seal unit (80) engages the gate (14) during the opening and closing cycles and prevents any discharge seeping between the primary sleeves from leaking to the atmosphere around the gate (14) or on the actuator end of the valve. An enlarged clean out area (70) cast into the housing (11) extends circumferentially around the primary sleeve units (53,54) in one embodiment so as to provide containment for any discharge during an actuating cycle. The housing (11) is further provided with flush ports in fluid communication with the clean out area (70) to allow controlled draining or flushing of the contained slurry. The gate valve construction of the present invention results in no leakage to the outside when the valve is fully open and no leakage to the outside or past the gate (14) internally when the valve is fully closed. <IMAGE> |
