When to apply gland steam sealing ??

[Yobbo]

L.S.,

I am not very familiar with the principle of gland steam sealing. What I do know, is that gland steam is applied, when at the process side there's only low pressure steam and the other side there is a possibility of in leaking air. Gland steam will prevent air from leaking, but will leak into the system itself.
Now I am confronted with a question to extend the use of gland steam seals to two HP steam valves in order to prevent leaking in of ambient air. This procedure will be solved by the valve supplier I suppose, but what I need to find out is what amount of extra consumption that will require. Are there any guidelines in general to find out this? Or is this a question for the valve supplier as well?

Another, maybe even more interesting, issue is how to establish whether we really need to switch over from a stuffingbox seal to a gland steam seal? I suppose medium pressure and temperature and valve size are important factors to consider. I can't find anything usefull on the internet though.

You can help me with literature reference, applicable internet sites or reference to expert suppliers.



Karel Postulart, The Netherlands
Nuon Power Generation

 

[rmw]

I remember some Copes Vulcan valves that had gland sealing on them (remember them because the sealing steam was off and they leaked air into the condenser). I googled "copes vulcan gland steam" and got a few interesting hits. I also googled "Leslie gland steam" and most of the hits had to do with their famous gland seal steam control valve. Still there may be something in some of those links for you.

rmw