GE Frame 9FB Air Intake


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Our project consist of (2 x 9FB)+(D11 ST), gas turbines will be equipped with Donaldson pulse filtration system. Filtration is in three stages and the first two stages are installed on the inlet hood (coalescing and course filter). I have just noticed on the P&ID that the filter house will contain inlet hood bypass system, activated by differential pressure and allow air to bypass directly to downstream high efficiency cartridge filters. This system allows on-line replacement of filters on the hood.

Spending 20 years in this field and experienced on varying filtration systems, I have never seen such a system on other projects. I have google it and managed to find only patent documents with recent dates detailing the hood bypass.

Can anybody share experience on "Inlet Hood Bypass" system?

This sounds relatively new, indeed. It's long been a source of frustration for many owners/operators that they have to shut down to change inlet air filters. This sounds like a method for changing coarse filters without having to shut down.

Have you tried contacting Donaldson and identifying yourself as owner:representative or operations department and asking for more information? If you have turbine serial numbers one would think they would be willing to share information. They've alwa been very helpful whenever I've contacted them for information or assistance in the past.

Please write back to let us know what you learn!
Thanks, CSA

It appears a very effective system that eliminates long unnecessary shutdowns in today's harsh power market conditions. We have already conveyed our concerns to GE and awaiting response, as they are the equipment supplier. We just want to be ensured that this system is not a prototype and has proven track record in service.

If anyone is interested to get informed, just google the patent number; US 2014/0123621A. You can find detailed step by step explanation with drawings.