I haven't had a chance to make any real progress this week, so I'll post some photos of the first stage workings. There is a surprising mechanism within the first stage that operates the first stage poppet, unlike anything I have seen before in a regulator. I'll show that later, but first things first.
Here's a look at the first segment of the first stage, with some explanations below the photo.
24.1st stg orifice + bypass.JPG
The first stage air inlet orifice is found in the small aluminum body with the manual bypass mechanism. The HP poppet is the light colored object that looks a lot like a miniature revolver cylinder. It has six holes that are are just air passages. The red valve knob allows user to bypass air around the seat mechanism in the event of some malfunction there. It allows fine tuning of a constant flow of air (from very slight to fairly heavy flow) which might be of some use to a diver if exertion requires greater volume than the demand functions can provide. The pick is pointed to one of the free flow orifices bypassing the brass volcano orifice and poppet, also bypassing the 2nd stage demand valve, and leading directly into the main regulator body. Four of the other holes are for the machine screws that hold this mechanism in place on the main body. Sort of comforting to know you have a straightforward source of air in case the first or second stage goes kaput, so I'm leaving it intact and functional.
23.first stage nozzle + seat.JPG
Here the poppet is shown in position. The small brass screw and nut is the contact point for the activating mechanism of the 1st stage. It is adjustable, but otherwise just performs the same function as the pin in a diaphragm type first stage. But, this sophisticated regulator does not have a diaphragm, or type of spring that we are familiar with. The unique pressure sensing mechanism pushes a lever that pushes against the poppet screw, thereby pushing the seat against the brass volcano orifice, and shutting of the HP air when there is no demand for air. When user inhales the second stage opens, intermediate pressure drops allowing the poppet seat to open and provide air flow. So it acts like any other first stage, but it's not.
26.bellows 1st.JPG
In this photo the rest of the first stage is shown with its relief valve/cover removed, revealing a sealed air filled brass bellows. When the surrounding chamber fills to proper pressure the bellows is compressed in length, pulling down on the lever attached at its top end. The other end of that lever pushes the poppet into the closed position until the pressure drops upon the next inhalation. The small hole in the side of that first stage chamber leads to the second stage. When the second stage lever is pulled down upon inhalation the air flows to left, into white tube that I added. That connects to the brass tube that is aimed directly at the inhalation hose opening.
I hope to have some time this weekend to reconfigure the hoses in a manner that does not allow exhaled air to enter the regulator body.
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