Gate valves mustn't be used in the regulation or throttling of flow because accurate control isn't likely. Furthermore, high-flow velocity in partially opened valves could cause erosion from the discs and seating surfaces. Vibration may also result in chattering from the partially opened valve disc. An exception towards the above are engineered gate valves which are used for low-velocity throttling; for instance, guillotine gate valves for pulp stock.
There are four primary designs for gate valve – a slab gate, an expanding gate, a wedge valve plus a knife gate valve.
Slab gate valves are comprised of your single gate unit which raises and lowers between two seat rings and are also primarily used by transporting crude oil and NGLs. The Cameron GROVE G4N fabricated gate valve and WKM Saf-T-Seal gate valve are perfect choices for this application.
In the 1800s, intensive continuing development of gate valves moved quickly forward this can increasing use within industrial operations. Over time the types of materials involved in their manufacture were improved and modified to accommodate different applications.A hollow wedge is often a variation of solid wedge excluding a hole inside center. The hollow wedge travels on the stem once the threaded stem is rotated, thus opening or closing the valve port.
The flexible wedge is usually one-piece construction such as a solid wedge, but areas behind the seating surfaces are hole to provide flexibility. This construction compensates for modifications to seat alignment for improved seating and the strength of a good wedge within the middle. This design offers better leak tightness and improved performance in situations with possibility of thermal binding.