Externally adjustable/serviceable regulator

[sb327]

I have thrown this design together to test. Bob explained in another topic how a knife edge type regulator works. This is just a knife edge with the internals turned inside out with two points needing atmosphere.

Dave

[rsterne]

The design looks promising, but the lower photo appears to show the seat (which I assume is the white plastic disc) a separate part from the regulator body.... with no method of sealing it to the body.... HPA could easily leak around the edges of that disc to the LP side, and the regulator would bypass....

If the seat was made thicker, with an o-ring groove around the outer edge to seal it inside the body, it would probably work as intended....

Bob

[sb327]

It is actually sealed by the large thimble to the far left. The passage hole drilled into it is stepped. This should allow the pressure difference you mentioned in a previous thread.

That large thimble holds it (the wafer) to the bottom of the knife seat and seals it (the wafer). The thimble design was used as a safety measure in case the center shaft failed. It will contain the hp side piston.

The seal area on the large thimble also has a small step that actually does the sealing towards the center. I didn’t want to curl the disk by needing too much torque for it to seal.


Dave

[rsterne]

I guess I don't understand, because that disc is not shown in your drawing.... I do understand that the movable knife edge on the HP piston seals against that disc.... Are you saying that the "thimble" on the HP side is not as drawn, and has a second knife edge that tightens against the disc as well?....

Bob

[sb327]

That’s correct. The drawing is just as a basic conceptual drawing. I’ll try to sketch up something that shows it as built.

Dave

[sb327]

This is the as built relationship of the parts on the hp side only.

Dave

[rsterne]

Yep, that should work OK....

Bob

[happymecanic]

Very nice work Dave!

[sb327]

Thanks.

 It holds pressure and does regulate/respond to adjusting. I have not got to try it on a plenum of size and I have not tested stability/recovery  in shooting. I will also need to determine what swing it has as input pressure changes.

I’m hoping to be able to use this as my inline tethering regulator and if the design proves itself, use it in an upcoming build.

Obviously the adjustment side will end up shorter but I wanted some extra room there in development so I could see how tall my Belleville stack needed to be.

Dave