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About:
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Gate and segment
There are four primary designs for gate valves.
Slab gate valves comprise a single gate unit that raises and lowers between two seat rings and are primarily used for transporting crude oil and NGLs. The G4N fabricated gate valve in the GROVE valves portfolio and the WKM Saf-T-Seal slab gate valve are ideal choices for this application.
Expanding gate valves include two units—a gate and segment—in contrast with slab gate valves, which have one unit. The gate and segment units collapse against each other for travel and separate when the valve is fully opened or fully closed to affect a mechanical seal.
Wedge gate valves are engineered with a tapered gate with metal-to-metal sealing. In contrast with a slab or expanding gate valve, wedge gate valves are not piggable because of the void that is left in the bottom of the valve body when the valve is open. These valves do not have a bore through the gate itself; instead, the gate retracts into the valve body when open, which saves height space.
Knife gate valves are used to cut through extremely thick fluids and dry bulk solids. The design of this valve makes it inherently self cleaning because the knife is cleared of abrasives with each stroke as it passes the seat rings and skirts. The gate unit of this type of valve is thin compared with other gate valve types and is guided in place by the water-type body that sandwiches the gate.
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