Gate valves are designed to start or stop the flow, and when a straight-line flow of fluid and minimum flow restriction are needed. In service, these valves generally are either fully open or fully closed. They are installed in pipelines as isolating valves and should not control valves. A gate valve consists of a valve body, seat and disc, a spindle, gland, and a wheel for operating the valve.
Gate valves aim to be cheaper than ball valves of the same size and quality. They are slower in actuation than quarter-turn valves and are for applications where valve operation is limited, such as isolating valves. Gate valves should be used either fully open or fully closed, not to regulate flow. Automated gate valves exist with either an electric or pneumatic actuator, but a manual gate valve is cost-effective as they have infrequent usage.
Where are Gate Valves used?
Gate valves are often used when minimum pressure loss and a free bore is needed. When fully open, a typical gate valve has no obstruction in the flow path resulting in a shallow pressure loss, and this design makes it probable to use a pipe-cleaning pig. A gate valve is a multiturn valve meaning that the valve's operation is done utilizing a threaded stem. As the valve has to turn multiple times to open to a closed position, the slow process also prevents water hammer effects.
Gate valves meet most valve requirements in process piping. They are considered one of the most used valves of all the valves employed in refineries, petrochemical, and gas processing plants where pressure remains relatively low, but the temperature may be very high. They are suitable for most fluids, including steam, water, air, and gas.