What is gate valve
    A Gate Valve, or Sluice Valve, as it is sometimes known, 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 valve is 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 sometimes used for regulating flow, but many are not suited for that purpose, having been designed to be fully opened or closed.When fully open, the typical gate valve has no obstruction in the flow path, resulting in very low friction loss. Gate valves are characterised as having either a rising or a nonrising stem. Rising stems provide a visual indication of valve position. Nonrising stems are used where vertical space is limited or underground. Bonnets provide leakproof closure for the valve body. Gate valves are typically constructed from cast carbon steel valve, gun metal valve, stainless steel valve, alloy steels, and forged steel valve.
How to install forged steel Valve
    Always follow standard safety procedures when working on a forged steel valve. The forged steel valve should be welded onto the line with the wedge in the fully closed position. Leaving the valve even partially open can cause distortion and leaking. Verify the drawings to make sure that the forged steel valve has bi-directional sealing capability. If the forged steel valve only has unidirectional sealing capability, make sure it is installed into the pipeline in the correct orientation. Single direction sealing gate valves have a nameplate on the side of the valve that has a relief hole or pressure equalizer. This should be the high pressure side when the forged steel valve is closed.