Steam Valves Key Terms

Understand steam valves key terms to make smarter choices

By Howard Robertson

A steam valve is an important component of a steam system. Steam valves come in different types and you must understand which type of steam valve best suits your application requirements. In addition, you will also need to know some technical language. A valve supplier might ask you about your requirement for flow coefficient (Cs) of the steam valve. This guide intends to introduce some of the steam valve key terms that you will hear from the professionals in the valve industry.

Control valve

As the name indicates, a control valve regulates the flow of fluid passing through the valve. Depending on the application requirements, a control valve can be mechanically operated, electrically operated or hydraulically operated.
Try: Emerson Electric, a supplier of industrial valves and accessories, has extensive information on control valves.

Ball valve

A ball valve is a valve with a spherical closure member. Although they are reliable, fixing ball valves is a time-consuming task. Generally, a metal ball valve is more durable than a plastic ball valve.
Try: Specialty Valve & Fitting, a supplier of valves, provides a definition of ball valves.

Butterfly valves

These valves are suitable for controlling the flow in a steam system. A butterfly valve has a circular disc or vane with its pivot axes at right angles to the direction of the steam flow. When rotated on a shaft, the circular disc seals against the seat in the valve body and restricts the steam flow.
Try: At Global Spec, you can read through basic information about butterfly valves.

Safety-relief valve

A safety-relief valve (sometimes referred to as a relief valve) is necessary for the safe operation of a steam system.
Try: Visit PDH Online for more information.

Gate valve

A gate valve has a gate that moves perpendicularly to the flow of the steam. Gate valves are an on/off type of valve.
Try: Crane Supply, a distributor of valves, fittings and piping accessories, provides a glossary for various key terms, including gate valves.

Solenoid valve

A solenoid valve is a control valve with a solenoid actuation mechanism. This actuation mechanism can be electric, electro-hydraulic, electro-pneumatic or pneumatic.
Try: Valve World, a magazine for the valve industry, provides a glossary for various key terms, such as solenoid valve. You can also read through the glossary at Shippensburg Pump Co., a supplier of parts for boiler steam systems.

Flow coefficient (Cs)

This term is also known as the steam-valve-sizing coefficient. At low operating pressures, there is a relationship between this coefficient and the gas-sizing coefficient.
Try: Fisher Controls, an Emerson group company, provides a glossary, including the definition of flow coefficient.