Stainless steel gate valves

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. Because of their ability to cut through liquids, gate valves are often used in the petroleum industry. For extremely thick fluids, a specialty valve often known as a knife Gate Valve is used to cut through the liquid.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 tends to vibrate from the fluid flow.

Working principle of the gate valve

Gate valves are actuated by a threaded stem which connects the actuator (e.g. handwheel or motor) to the gate. They are characterised as having either a rising or a nonrising stem, depending on which end of the stem is threaded. Rising stems are fixed to the gate and rise and lower together as the valve is operated, providing a visual indication of valve position. The actuator takes the form of a nut which is rotated around the threaded stem to move it. Nonrising stem valves are fixed to, and rotate with, the actuator, and are threaded into the gate. They may have a pointer threaded onto the upper end of the stem to indicate valve position, since the gate's motion is concealed inside the valve. Nonrising stems are used underground or where vertical space is limited.

Bonnets provide leakproof closure for the valve body. Gate valves may have a screw-in, union, or bolted bonnet. Screw-in bonnet is the simplest, offering a durable, pressure-tight seal. Union bonnet is suitable for applications requiring frequent inspection and cleaning. It also gives the body added strength. Bolted bonnet is used for larger valves and higher pressure applications.

Another type of bonnet construction in a gate valve is pressure seal bonnet. This construction is adopted for valves for high pressure service, typically in excess of 2250 psi (15 MPa). The unique feature of the pressure seal bonnet is that the bonnet ends in a downward-facing cup which fits inside the body of the valve. As the internal pressure in the valve increases, the sides of the cup are forced outward. improving the body-bonnet seal. Other constructions where the seal is provided by external clamping pressure tend to create leaks in the body-bonnet joint.

Gate valves may have flanged ends which are drilled according to pipeline compatible flange dimensional standards. Gate valves are typically constructed from cast iron, ductile iron, cast carbon steel, gun metal, stainless steel, alloy steels, and forged steels.

All-metal gate valves are typically used in ultra-high vacuum chambers to isolate regions of the chamber

Materials
All fabricated steelwork used in the construction will be to manufacturing standard of normal or classification society.
All materials proposed will be selected to comply with the latest Health and Safety Rules.
Paint systems for hull protection will be of the highest quality (Hempel, Inter, Sigma, Jotun)

Welding
All welding will be performed in accordance with drawing and order and UniSite experience and all welding will be continuous and full penetration.

Workmanship
The workmanship have good marine practice. Care are taken to ensure fair lines, smooth surfaces and neat welding.

Photos of our Stainless steel gate valves

Our service
Besides above the general specifications, we can also supply some specific dredge valve gate and other similar steel structure as clients' requirements.

Package and shipping
bulk package and bulk vessel transportation
container package and container transportation

How to contact us?

Send your Inquiry Details in the Below, Click "Send" Now!

Contact us if you need more details on High Pressure Gate Valve. We are ready to answer your questions on packaging, logistics, certification or any other aspects about Stainless Steel Gate Valves、Pressure Seal Gates Valve. If these products fail to match your need, please contact us and we would like to provide relevant information.

Product Categories : Steel Structures > Gate Valve