Originally Posted by
Viper1GJ
Hi Oli,
Ref your statement above: The plastic push-to-connect fittings most people and manufacturers use ( QStype Festos fittings) are not designed to be used with fuels.
All of the turbines I have ever owned have festo fittings for fuel input. Is this a problem over time on the engines themselves? I have never had an issue but am surprised the turbine mfg. use them based on your statement.
Gary
Not entirely. The Festo fittings are designed to work with petroleum based lubricants that are used to lubricate air cylinders and keep seals from drying out. If we had used pure kerosene which depolymerizes many plastics and rubbers then maybe. But we run oil as well. The 2 main issues are the fact that the inward pressure from the retaining barbs and low pressure does not mach the design intent of positive pressure which allows the seal to collapse. They are perfectly OK for handling pressure up to 10 Bar (145psi). Also the seal in not an o-ring but a flanged seal, certainly not suitable for negative pressure at all.