Air Valve Isolation

[HydroJo]

Some air valve models have a built in isolation valve, like a plug valve in the base of the bowl. This is inplace of a separate gate valve or butterly valve fitted betwee the pipe T and the air valve.
Such integral isolation valve would possibly permit the valve bonnet to be open for inspection of the floats - BUT not permit removal of the whole AV without dewatering the pipeline.
Does anyone have experience of successful operation of such air valves in maintenance situations?

 

[PUMPDESIGNER]

We recommend a separate ball or butterfly valve (depending on size), isolating the air valve from the line for maintenance or replacement.

PUMPDESIGNER

 

[stanier]

If the air valve is in a pit and you are limited in space you could use a knife agte valve. However these need regular maintenance as they can leak at the seal.