Gate Valve Gate valves has served more then 150 years in virtually every refinery, chemical plant and industrial facility in the world.Gate valves are the most common valves used in on-off services. They are used where stop valves are required and will stop flow in either directions, i.e., they are "bidirectional". They are often used as isolation valves,also called block valves. Gate valves are manufactured in sizes ranging from 1/2 inch to approximately 36 inch.Gate valves are manufactured in a wide range of sizes- from ¼” through 144”. Gate valves should be used either fully closed or fully open; never in a throttling position. Gate valves should be used either fully closed or fully open; never in a throttling position.
They offer low resistance to flow and cause low pressure drop.Only a full port ball valve can equal the gate valve’s flow characteristics.It is not recommended to operate gate valves in the partially open position, or to use them in throttling service. When a gate valve is partially open, it closure element (disc or wedge) can vibrate against the seats and become scratched causing them to lose their seating integrity.
From the outside, most gate valves look somewhat similar. However, inside there are a host of different design possibilities. Most gate valves consist of a body and bonnet that contains a closure element, called a disc or a gate. The closure element is attached to a stem that passes through the bonnet of the valve, ultimately interfacing with a handwheel or other device to operate the stem. Pressure around the stem is contained through the use of packing material which is compressed into a packing area or chamber.