Help identifying Poseidon first stages

[stiebs]

In the lead up to taking @rsingler 's Regulator Technician's course I picked myself up a couple of Poseidon regs 2 first stages and 4 Jetstreams. Having never used Poseidon's before, it's been a learning curve even figuring out their model numbers, and @rsingler has been very generous with his knowledge and wisdom as well!

So now that I've pulled apart both of my first stages, one of them matches perfectly with the service manual for the 2962 first stage, as expected.
The other one matches reasonably close, but in my pictures below I've highlighted some differences. The second one (with the parts circled in white) appears to be a 2962 that's been Frankensteined with parts from a 3790?

I'm not sure if it makes a difference, but one of them (the pure 2962) has a polished sheen, whereas the other has more of a matt finish.

Does anyone else have a take on this?



The differences I've noticed between the two are:

1. Adjusting screw - 2962 is raised, Frankenstein is flat
2. Spring - 2962 has an inner and outer spring, Frank has a single spring (as per 3790 diagram)
2a. (not circled) Diaphragm centres match the single/dual spring
3. Spring guide - 2962 has one, Frank has a piece that looks like the part of the 3790 safety valve.
4. Pressure spring - 2962 is wide enough to fit over the spring guide, Frank's is narrower
5. Locking screw -2962 is longer
6. 2962 has an o-ring that goes around the filter. Frank has a spring
7. Filter - 2962 filter is shorter. Frank's was installed upside down (pointy end toward the first stage)

You can see that two of Frank's orings are split (not circled). Both these orings are very hard and brittle, and have a squared profile. Almost like a plastic bushing rather than an oring. But I'll put that down to age deterioration.

 

[Bigbella]

I seriously doubt that anything was particularly "Frankensteined" in either regulator (there's little room for it), though I am currently seeing it on a dinky screen; and that that matte finish that you mentioned is somewhat common -- even one of my older Xstreams has that "satin" appearance: cosmetic, nothing more.

Was either one just sold for parts?

There was a significant overlap, in terms of parts, with some earlier first stages, over the years, which can even be traced back to the last model of the old Cyklon 300 line, the 2940, which shared the same cover for the valve housing and its adjusting screw -- and was carried through, to all of the later 2900 and 3900 models; and only ended with the development of the Xstream.

Many internal components were also common among some first stages -- seats, pistons, sintered filters, springs, etc, with only the 3950-60 first stages, possessing the integral OPVs, within their base . . .

Good luck with your class; you're in good hands . . .