Problems with Metal Seated Gate Valves on Steam Application

[JohnMack30]

Does anyone experience problems with Metal Seated Gate Valves seizing or leaking excessively on Steam Application? Is there another style of valve that is more reliable anyone can recommend that I investigate.

 

[ricklts]

we use a lot of metal seated ball valves, but most of the gate valves we use are slab gate design. contact bel valves in the UK and ask. they are the best.

good luck,
Rick

 

[bcd]

Metal seated gates are commonly used in steam. So are soft and metal seated ball, butterfly, and globe valves. Choice depends upon size, pressure/temperature, end connection, and lots of other factors. Lots of different types of steam systems. Big difference between main steam isolation and throttling in a Nuclear power system versus an industrial steam heating system.


Gate valves can stick, especially with solid wedges and thermal cycling. Packing is more likely to leak versus rotary motion ball and butterfly becuase of the amount and direction of stem movement through the packing as wel as thermal gradients along the stem. But that is offset by them being about as inexpensive a metal seated high temperature valve one can purchase.

 

[steamdog]

We supply steam PRV equipment and although the gate valves are the least expensive alternative they are used extensively. We have had more success for critical applications using metal seated high performance butterfly valves and soft seated ball valves (with the correct seats for pressure/temperature). You did not mention the pressure/temperature of your steam, as this will limit the selection as well

 

[gerhardl]

If constructed for steam use and used correctly, any valve will function without problems for a long time. This is however only if the piping is laid out properly and the valves are used correctly. (On-off valves must be closed and opened 100%, and not be used as regulating valves, if not constructed for the purpose.)

For most systems lay-out, use and maitenance will not score at the very top of the scale. The result is that unproper drainage, inside impurities and not properly or already damaged sealing surfaces, will give haircracks and increasing leakage and cavitation over the valves. Possibly also waterhammer by upstart.

In my general experience some choices might give longer-lasting valves: globe-valves with protecting skirts for sealing surfaces, or globevalves moderated for regulating but used as on/off, bellow sealed stems, or ballvalves with carbon-reinforced seat-sealing rings Also some 'upper class' metal- seated butterfly valves with special construction and/or double eccentric construction might be a sensible choice.

For drainage steamtraps,vacuum-breakers, regulating valves/stations,safetyvalves specialists must be contacted for proper lay-out and selection of components.

Your problem indicates that there is a general potential for improvement in your system by checking all layout and components, not only the valves.