Valves and Valve Equipment

Steam Valves: Types, Features and Choosing the Right Valve

Compare the design, advantages and typical duties of globe, piston, gate, metal bellows and bronze steam valves, and learn the key criteria for choosing the right one.

ORFA Technical TeamUpdated: Oct 30, 20263 min read

Steam lines are a demanding environment for valves because of high temperature, pressure and condensate. A poorly chosen valve can cause leaks, energy losses and safety risks. Steam valves are designed with materials and sealing arrangements that withstand these conditions and are offered in different types, such as globe, piston, gate, metal bellows and bronze valves, according to their duty.

This article covers the common types of steam valves, their key features, the duties they suit and the basic criteria for correct selection.

Types of Steam Valves

Globe Valves

In a globe valve the disc closes onto a seat perpendicular to the flow. This allows precise flow regulation (throttling) as well as reliable shut-off. Because the flow path is tortuous, pressure loss is higher than in a gate valve.

Piston Valves

In piston valves, sealing is achieved by a piston sliding between two sealing rings. As the piston moves it wipes the sealing surfaces, giving a self-cleaning design that resists deposits. The sealing rings can be replaced without removing the valve from the line, making maintenance easy.

Gate Valves

Gate valves do not restrict the bore when fully open and offer low pressure loss. In steam lines they are used for isolation (on/off); leaving them partly open for throttling causes wear on the gate and seat.

Metal Bellows Valves

In metal bellows valves the stem is sealed by a stainless steel bellows. This prevents gland leakage, making them the choice for steam, thermal oil and other services where leakage is unacceptable.

Bronze Valves

These have bronze bodies and usually threaded ends. Thanks to their corrosion resistance and compact design they are used in small-bore steam, hot water and marine lines; their allowable pressure and temperature are lower than those of steel valves.

Comparison of Types

Valve type	Main duty	Key feature
Globe	Regulation (throttling) and shut-off	Precise flow control
Piston	Shut-off	Self-cleaning seal, in-line maintenance
Gate	Isolation (on/off)	Low pressure loss
Metal bellows	Shut-off and regulation	Stem seal without gland leakage
Bronze	Shut-off and regulation in small sizes	Corrosion resistance, threaded ends

What to Expect from a Quality Steam Valve

Reliable sealing: No leakage at the seat or the stem; steam leakage is a direct energy loss.
Suitable materials: Body and internals must suit the pressure and temperature of the line.
Long life and low maintenance: Durable internals and easily replaceable seals reduce operating costs.
Design suited to the duty: Use globe valves where regulation is needed, gate or piston valves for isolation, and metal bellows valves where leakage is critical.

Applications

Steam valves are used primarily in industrial steam and condensate systems. Depending on type and material, they may also be used for hot and cold water, compressed air, thermal oil and some process media; for each application, check the valve’s suitability for the medium and operating conditions in the product catalogue.

Tip: When bringing a cold steam line into service, open the main valve slowly and make sure condensate in the line is drained. Opening suddenly can drive accumulated water at high velocity and cause water hammer.

Frequently Asked Questions

Which valve should be used for flow regulation in a steam line?

Use a globe valve or a control valve wherever regulation (throttling) is needed. Gate valves are designed to operate only fully open or fully closed.

When is a metal bellows valve preferred?

Where stem leakage is unacceptable, maintenance access is difficult, or leakage of media such as thermal oil or steam would mean energy loss or a safety risk.

What is the advantage of a piston valve?

Sealing is achieved by the piston sliding within sealing rings; this design is self-cleaning against deposits, and the sealing rings can be replaced without removing the valve from the line.

Conclusion

Steam valve selection should consider the valve’s duty (regulation, isolation or leak sensitivity) together with the pressure, temperature and size of the line. A valve of the right type and material prevents energy losses, lowers maintenance costs and improves operating safety. You can explore all valve types in our valves and valve equipment product group.

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