A Gate valve is really a linear motion on-off or shut-off valve. The gate-valve covers a disc or wedge having two seating surfaces that will in contact while using valve seats to create a seal for stopping the flow check here. The pressure differential between upstream flow direction and downstream side of wedge causes the wedge or disc to push against the downstream seat creating more effective sealing around the downstream side with the wedge. Gate valve sits dormant to regulate flow as erosion of disc and seat might cause leakage. A gate valve in partially open or closed position is additionally susceptible to vibration.
The shut-off part on the gate valve is created in the form of your wedge, which is often flexible, with multiple plates or rigid.
Let us look into each on the subcategories:
Rigid wedge
To ensure an increased hermiticity of gate valves, it is strongly recommended to choose a stiff wedge. In this case, you will need to pay attention towards the accuracy of wedge processing, that allows to coordinate the seat angle while using wedge angle without obstacles. In addition to that, rigid wedge application might result in dangerous events like gate jamming, or there is problems using the opening of gate valves in the event of temperature fluctuations, corrosion build-up or sealing damages.
Wedge with 2 plates
The wedge includes several plates that are securely certain to each other and are also situated with an angle. Thanks to self-adjustment, the problem on the gate hermiticity inside the closed position is usually avoided.
Flexible wedge
Connected with the elastic part, the plates can clamp down and enhance the sealing tightness in closed position. The advantage of gate valves having a flexible wedge for mounting within the pipeline is the fact there is no need of your complex adjustment from the valve body.
The varieties of rising-stem gate valve may be divided into wedge disc gate valve and parallel disc gate valve based on the sealing surface configuration. Wedge disc gate valve is usually divided into: single disc type, double disc type and elastic disc type; parallel disc Type gate valve may be divided into single disc type and double disc type. According towards the thread position from the valve stem, it may be divided into rising-stem gate valve and non rising-stem gate valve.
When the rising-stem gate valve is closed, the sealing surface is only able to rely around the medium pressure to seal, that's, only rely within the medium pressure to press the sealing surface in the disc towards the valve seat for the other side so that the sealing from the sealing surface, and that is self-sealing. Most gate valves adopt forced sealing valve, that's, if your valve is closed, the disc need to be forced for the valve seat by external force to guarantee the tightness from the sealing surface.
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