metal to metal

[pvvgnl]

Hello,

I want to know please if the metal to metal seat / ball ( ball valve) is suitable for gas service.
thanks

 

[gerhardl]

Depends on requirement for thightness (allowable leakage, and required tests for this leakage), if if the ball valve is of a construction and the application of such type that this requirement can be expected for the duration of the expected or required lifetime for the application.

A combination or laminated seat might be more what you are looking for. Firesfae certification?

 

[pvvgnl]

Thanks you for your answer, gerhardl. The valve is not TSO, we thing to change it from soft seat to metal to metal. with the soft seat the valve become passing because of black powder in the gas stream.
Also I want to know please if the sealant injetion will be dangerouse one we have metal to metal valve.
Thanks

 

[hsbcn]

What is pressure-temperature for this application?

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[ballvalveguy]

Hi PVVGNI,

There would be two reasons to go to metal seats on this application:

1). It is very abrasive (although there are some instances where you could use a "soft" abrasion resistant seat.

2). The temperature is above about 500F.

What is the gas? What is the pressure? What is the temperature?

 

[pvvgnl]

the gas is natural gas.
operating temp is 62 C.
Operating pressure 101 barg.
Thank you in advance

 

[ballvalveguy]

If the problem is abrasives in the natural gas (black powder), there are soft seats that are far more abrasion resistant than Teflon. I would look at Devlon or even UHMWPE. Both are much less expensive than metal seats. Check out

http://www.goscovalves.com,

http://www.mogas.com

or

http://www.valv.com

All these companies make metal seated valves with a class VI shut off, and should be able to provide soft seats in the materials above as well. None of these companies are the cheapest out there, but they will all be able to solve your problem.

 

[NGiLuzzu]

pvvgnl,
is the valve type (i.e. ball) a mandatory requirement?

If not, maybe you can switch to a "lighter" design (e.g. triple-offset butterfly) keeping the metal seating with the relevant abrasion resistance, while saving total metal weight in the meantime...(?)

Hope this helps, 'NGL