Threaded connections for Automatic air vent and Pressure Relief valves for Jet fuel service
Threaded connections for Automatic air vent and Pressure Relief valves for Jet fuel service
(OP)
I have the filter water separator and the Filter monitor vessels for the Jet fuel service and they have the threaded connections at the top of these vessels for air vent and the Pressure relief valves. Our client is having a concern that for the jet fuel service we need to avoid the threaded connections and also while removing the air vent valve for any maintenance and fixing back the threads may get damaged and insisting to give flanged connections.
Vendor refuses to comply with this as this is their standard design and cannot change it. I have also checked all other suppliers of similar aviation fuel service filters and monitors and there also it is threaded connection only.
The vendor is not able to give any technical reason why it should be threaded connection and my query is why all the vendors have such air vent valves in threaded connection?
Thanks to reason it out and reply
Vendor refuses to comply with this as this is their standard design and cannot change it. I have also checked all other suppliers of similar aviation fuel service filters and monitors and there also it is threaded connection only.
The vendor is not able to give any technical reason why it should be threaded connection and my query is why all the vendors have such air vent valves in threaded connection?
Thanks to reason it out and reply





RE: Threaded connections for Automatic air vent and Pressure Relief valves for Jet fuel service
There is no particular issue over the fact that it is jet fuel service for threaded connections and I have seen many small bore these connections in this service as they are much easier to instal and have much less weight, which is a primary concern of the vendor, especially on relatively thin vessels and small bore connections. I wouldn't normally recommend anything less than a 2" connection, reducing to a1"flange for strength reasons if there was a flanged connection due to the extra weight.
I would suggest a compromise along the lines of a screwed pipe into the vessel (maybe even seal welded if the client insists) and then either a flange on that pipe (maybe a bit heavy for the threaded connection) or a split connection (threaded connection) or screwed coupler which allows the valve to be removed easily and if they mess the threads up when they put it back then they can easily replace it. The client has the operating experience and in the past has probably had a vessel go out of service for a long time because a fitter broke the threads during maintainence.
Good luck as it sounds as if you're being squeezed from both sides...
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Threaded connections for Automatic air vent and Pressure Relief valves for Jet fuel service