The gate valve, alternatively known as a sluice valve, is a valve that opens by lifting a round or rectangular gate/wedge out of the path of the fluid. The distinct feature of a gate valve is that the sealing surfaces between the gate and seats are planar. The gate faces can form a wedge shape or they can be parallel. Gate valves are primarily used to permit or prevent the flow of liquids, but typical gate valves shouldn’t be used for regulating flow, unless they are specifically designed for that purpose. For very viscous fluids, or with abrasive particles and properties a specialty valve known as a knife valve is used and which can cut through these particles.
On opening the gate valve, the flow path is enlarged in a highly nonlinear manner with respect to percent of opening. This means that flow rate does not change evenly with stem travel. Also, a partially open gate disk tends to vibrate from the fluid flow. Most of the flow change occurs near shutoff with a relatively high fluid velocity causing disk and seat wear and eventual leakage if used to regulate flow. Typical gate valves are designed to be fully opened or closed. When fully open, the typical gate valve has little or no obstruction in the flow path, resulting in very low friction loss.
Gate valves have either a rising or a non-rising stem. Rising stems provide a visual indication of valve position because the stem is attached to the gate such that the gate and stem rise and lower together as the valve is operated. Nonrising stem valves may have a pointer threaded onto the upper end of the stem to indicate valve position, since the gate travels up or down the stem on the threads without raising or lowering the stem. Nonrising stems are used underground or where vertical space is limited. They are also generally preferred in the water industry as the sealing mechanism around the stem is easier to achieve.
Listed below are the types of gate valves we specialize in. If you would like more information or want to know specifically which valve you should use in your system, get in touch through our contact page.
- API Gate valves up to ANSI Class 2500
- RSV Gate valves – all formats and up to PN25
- Wedge Gate Valves for the water industry up to PN100
- Knife Gate valves in many different formats