Propane Manifold


With the banjo fittings done, I was able to proceed with the mounting of the propane manifold. This combines a solenoid valve with outlets for both the normal propane feed of the gas gennie and a takeoff feed for the pressure switch used to turn on the oil pump.

  The first step was to decide where to put the darned thing! Space is at a premium in and around the intake area of the turbine. I decided to set the body of the solenoid valve parallel to the turbine case outer. The output was then routed to the propane port on the face via a brass tube. You can see clearly here one of the completed banjo fittings to the right side of the manifold.
To route pressure to the pressure switch, I needed to "tap" the manifold. The pressure switch is located below and to the left of the turboprop when viewed from the rear. I could have simply cross-drilled and soldered a tube in place, but decided a more elegant solution was to have a rotating sleeve, sealed by o-rings. This setup will become clear as we proceed. The first step was to turn 2 o-ring grooves in the manifold body, as well as cross-drill the manifold.
The area around the cross-drilling was relieved a bit, and a brass sleeve was turned to seal this area. Here, the sleeve is slid a ways up the manifold to show the o-rings. A hole as drilled in the sleeve, and a correct tube was soldered in place.

Why such a torturous method? The sleeve can slide a bit longitudinally, as well as rotate, making final fitting very easy.

This is what it looks like mounted on the gas gennie! At the bottom of the picture is the connection to the pressure switch on the oil pump pack.

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