Flow valves control the flow or pressure of the fluid and are useful in varied applications. They are usually fitted with actuators and positioner, for the purpose of regulating the flow of any medium. They can also be used to control the speed of the actuator. These valves are less expensive and easier to control.

Excess flow valves:

Excess flow valves are self activating valves that close automatically, when the gas or fluid flow exceeds the specified level. These valves help to reduce the chance of blowing gas due to pipe line breaks, which are caused by natural disaster or thirty party damages. These flow valves are ideal for fuel lines, gas and hydraulic lines, petroleum installations, chemical processing, pollution control and many other applications.

How excess flow valves work:

The excess flow valve has a spring that pushes it open against the oncoming flow of gas. When more and more gas flows, the spring makes the valve seal to shut and thereby stops the flow of gas. If the lines in your gas system are repaired, the valve automatically resets itself.

Types of flow valves:

Flow valves come in different types; out of them needle valve is the simplest type. It has a small, needle like plunger, which helps the system to control the flow. It is advantageous to use the needle valve.

• Needle valve is perfect for flow metering applications.
• It is very easy to shut off the valves completely, by simply giving finger tight pressure.
• Needle valves are often used in hot water heating applications

Flow Check valves:

Check valve is one of the important types of flow valves, which allows the fluid to flow through the valve in one direction. These valves are often used in pumps, including piston driven, diaphragm pumps and chromatography pumps. These valves resemble small cylinder like structure and they are also used in fluid systems like those in chemical and power plants.

The flow check valves are especially useful in situations, where multiple gases are required to be mixed into a single gas stream. These valves assure the purity of the gas cylinders and are therefore nonflammable.