The most frequent form of valve used in a process plant is a gate valve. It is a linear motion valve that allows or prevents fluid flow. These valves are either fully open or totally closed while in use. The disk of the gate valve is totally disengaged from the flow when the gate valve is fully open. When the gate is lowered into the housing, it contacts the seal which prevents fluid from flowing through the valve when it is not activated.
There are two types of gate valves commonly used in industry today: balanced and unbalanced. With balanced gates, both sides of the valve operate equally when opened or closed. This means that the force required to open or close the valve is the same on either side. Unbalanced gates contain different amounts of pressure on each side when opened or closed. Thus, they require more effort to operate than balanced ones.
Gate valves are available in several sizes based on the diameter of the opening being controlled by the valve. Standard size gate valves have openings between one and four feet in length. Longer lengths can be obtained by combining multiple plates together. Gates can also be made out of other materials such as rubber or polyurethane. They tend to be heavier duty versions of standard plate valves.
Valves are one of the most important components in any system because they control the flow of material through a pipeline. A valve controls the flow of material by either allowing it to pass or preventing it from passing.
Valves and meters In general, a gate valve is used to totally shut off fluid flow or, when fully open, to provide full flow in a pipeline. As a result, it may be utilized in either the fully closed or fully open position. A gate valve is usually designed with a hinge or mechanism that allows it to be turned on its axis so that it can be opened from the outside of the pipe.
They are commonly used in gas pipelines to control the flow of fluid (gas) into or out of tanks or storage facilities. The term "gate" refers to the fact that when the valve is open, it forms an opening through which water, for example, can pass but not oil. When the valve is closed, there is no passage through which water can pass.
The most common type of gate valve used in industrial applications is the butterfly valve. This valve has two parts: a disk-shaped plate called a "butterfly" and a housing around the plate's edge. When the valve is in the closed position, the butterfly blocks the flow path through the center of the valve. But when the valve is in the open position, it leaves a hole through which fluid can flow.
Butterfly valves are typically used in applications where fluid flow needs to be controlled with minimal loss over a wide range of pressures and temperatures.
Gate valves operate by putting a rectangular gate or wedge into the flow channel of a fluid. They are controlled via a threaded stem that links the actuator (often a hand wheel or motor) to the gate stem. A gate valve has no restriction in the flow stream when completely open, resulting in a very low pressure drop. When closed, the gate creates a tight seal which prevents leakage while allowing fluid to be moved in either direction. The stem must be rotated in order to move the gate between open and closed positions.
Motorized gate valves are designed to reduce operating costs by eliminating the need for manual operation. These valves use electric motors instead of people to turn the handle or push button that operates the valve. Electric motors can run continuously without stopping to allow water to drain or refill tanks, reducing energy consumption and replacement costs. Motorized gate valves also provide additional safety features not found in manually operated versions. For example, if someone were to get their hand caught in the opening of the valve body, the risk of injury is reduced because the gate will close automatically.
Motorized gate valves are more expensive than standard gate valves because they require special components that are both durable and reliable. Also, since they do not have rigid parts such as handles or levers which can be broken, they must use electromagnets or other types of actuators instead.
Standard gate valves are still used in conjunction with motorized gates as backup mechanisms in case of failure of the electrical system.