Selecting the Right Gate Valves
As a China Gate Valve manufacture,I will share it with you.
The most popular style of valve in the world of flow control is the gate valve. They are the on/off switches of the fluid control industry and they are found in every refinery, chemical plant, power plant and industrial facility. Gate valves exist for one primary purpose- to stop flow. The chief advantage of a gate valve is that it offers virtually no resistance to flow in the open position.
Positives for gate valves:
When fully open, there is low resistance to fluid flow. The opening in the valve tends to mimic the cross sectional characteristics of connected piping and fluid can flow through the valve without a directional change.
Changing the gate position (opening or closing the valve) does not require as much force or power as some other valve types, due to the gate movement being perpendicular to the flow direction.
Gate valves work in both directions. The flow in the connected line can be reversed and the valve function is unimpaired.
The gate valve assembly tends to be shorter in length along the path of flow than some other designs.The rate of closure is generally slow, providing a graduated reduction in fluid movement and reduced physical shock to the piping system.
Materials of Construction for Gate Valves:
Gate valves are manufactured in virtually every metal from Aluminum to Zirconium. They are also manufactured in a variety of engineering plastics. The most common materials however, are steel, iron and bronze.
Bronze offers the greatest machinability and the lowest manufacturing cost. The features that make bronze easy to machine, its lower strength and softness, also make the valve only suitable for lower pressure applications. The predominant service for bronze valves is on water and utility lines where pressures are lower than about 300 psi.
Iron valves are in between bronze and steel as far as strength goes. The iron is slightly harder to machine, but the iron castings are relatively easy to pour. Iron for valves is commonly two types; grey or cast iron and malleable iron. In refinery and petrochemical service iron valves are usually restricted to low pressure water lines. The high carbon content and better rust resistance of iron valves makes them more suitable for buried service than steel valves.
For industrial valves, steel is the material of choice. A broad spectrum of steels are utilized for valve construction, from the lowest grade WCB, to the chrome/moly's. Unlike the brasses, bronzes and irons, most steels and low alloys are readily weldable, which makes them easier to modify, repair and in some cases even easier to manufacture. Gate valves are also manufactured in a number of exotic alloys from Titanium to Zirconium.
There are certainly more elements involved in proper valve selection than are shown here, but this quick check may help you focus on gate valves or another technology for further consideration.For more information and help, please contact us.