Gate valve, one of the most widely applied valves, is a valve that opens by lifting a gate/wedge out of the path of the fluid. The gate faces of gate valve could be a wedge shape or be parallel. Gate valves are not suitable for regulating flow, having been designed to be fully opened or closed. When fully open, the gate valve has no obstruction in the flow path, resulting in very high flow coefficient.
Gate valves have either a rising stem or a non-rising stem. Rising stem provide a visual indication of valve position. Non-rising stem is used where vertical space is limited or underground.
Kolink gate valves are supplied with three basic type of body-bonnet closures: bolted bonnet, welded bonnet and pressure seal bonnet. Bolted bonnet, the seal depends on the body-bonnet bolt preload to maintain sufficient compressive force, bolted bonnet is widely used for valves on various pressure ratings and sizes. Welded bonnet is mainly applied for small-size forged steel gate valves, suitable for applications requiring zero leakage on body-bonnet joint when carrying hazardous system fluids. Pressure seal bonnet is adopted for valves for high pressure service, typically in excess of 15 MPa (2250 psi). The body-bonnet joint seals improves as the internal pressure in the valve increases, compared to other constructions where the increase in internal pressure tends to create leaks in the body-bonnet joint.
Kolink gate valves are with flanged ends, butt weld ends, socket weld ends and screwed ends, and are constructed with various materials of cast carbon steel, stainless steel, alloy steels, and forged steels.
Various combinations of seating and stem materials are available to meet specific customer requirements.