The advantage of gate valves using a flexible wedge for mounting from the pipeline from aoaltwar's blog

A Gate valve is often a linear motion on-off or shut-off valve. The gate-valve consists of 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 involving the upstream flow direction and downstream side of wedge causes the wedge or disc to push against the downstream seat creating more effective sealing about the downstream side with the wedge. Gate valve just sits there to regulate flow as erosion of disc and seat might result in leakage. A gate valve in partially open or closed position can also be susceptible to vibration.

The shut-off part in the gate valve is created in the form of any wedge, which is often flexible, with multiple plates or rigid.

Let us check out each with the subcategories:
Rigid wedge
To ensure a higher hermiticity of gate valves, experts recommend to choose a stiff wedge. In this case, you should pay attention to your accuracy of wedge processing, that enables to coordinate the seat angle using the wedge angle without obstacles. In addition to that, rigid wedge application could cause dangerous events like gate jamming, or there is problems using the opening of gate valves in case there is temperature fluctuations, corrosion build-up or sealing damages.

Wedge with 2 plates
The wedge is made up of several plates which can be securely certain to each other and so are situated with an angle. Thanks to self-adjustment, the problem on the gate hermiticity inside the closed position might be avoided.

Flexible wedge
Connected through an elastic part, the plates can clamp down and increase the sealing tightness in closed position. The advantage of gate valves which has a flexible wedge for mounting inside the pipeline is the fact there is no need of the complex adjustment in the valve body.

The kinds of rising-stem gate valve may be divided into wedge disc gate valve and parallel disc gate valve in line with the sealing surface configuration. Wedge disc gate valve might be 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 on the thread position with the valve stem, it might be divided into rising-stem gate valve and non rising-stem gate valve.

When the rising-stem gate valve is closed, the sealing surface could only rely for the medium pressure to seal, that may be, only rely around the medium pressure to press the sealing surface with the disc on the valve seat for the other side so that the sealing with the sealing surface, that is self-sealing. Most gate valves adopt forced sealing valve, that may be, if your valve is closed, the disc has to be forced on the valve seat by external force so that the tightness from the sealing surface.