Maintenance of VA19 Valve When the GTG Is Running


Thread Starter


Is it possible to transfer all the equipment on the purge control valve, out of the turbine compartment?

The equipment includes: stone filter, pressure switch and the control valve (VA19) Subduct the equipment means that access for repairs VA19 even when the turbine is in service, to be provided. On both sides of the VA19 valve and stone filter, two isolation valves be installed.

By closing valves to isolate the path,
open the bypass valves
and repair the VA19 or clean the stone filter.
Bypass path without control valve and stone filter.

Gas turbine Model is:

Please help me.

Thanks a lot for reply

I've worked on a LOT of dual fuel machines and I can never remember every having to perform maintenance on VA19-1--ever. I did hear of one VA19-1 actuator diaphragm that ruptured, but that was because of a failure of the pressure regulator, and I would consider that a repair not maintenance.

What kinds of failures/problems is the site experiencing with VA19-1?

How often does the site run on liquid fuel?

How often does the unit start and stop (daily; weekly; once or twice a month)?

Sure, it would be possible to locate VA19-1 outside the turbine compartment. But in my personal opinion I would rather understand what the failures/problems being experienced by VA19-1 and work on resolving the cause of those.

If the site is a combined cycle power plant where there is a source of dry instrument air I would also suggest using the plant instrument air to operate VA19-1. That would eliminate the poro-stone filter, and using dry instrument air would be much more preferable to using compressor discharge extraction air. Also, the vessel the poro-stone filter is in is usually cast steel and rusts, and the low-point drain usually becomes plugged and that allows moisture to get to the actuator of VA19-1 and cause problems with the actuator--and the pressure regulator, because no one ever checks the liquid detector of the pressure regulator because of its location. (It's also a good idea to use dry instrument air for the compressor bleed valve actuators, also--if it's available. For the same reasons.)

But, if you can tell us what problems are being experienced we might be able to help with a solution that would prevent moving the valve and components outside the turbine compartment. The piping will be hot and will have to be insulated, and the valve body will also have to be insulated, or some kind of barrier to prevent people from getting burned will need to be erected around the valve. And, putting manual valves in this kind of application is just begging for a valve or both to be left in the wrong place at some point, leading to knock-on problems.

Please write back with more information, and we can try to offer some suggestions.