Q: Downstream Sampling Requlator

[cyoung]

The local LDS is coming up with a dedicated nitrox compressor.
I just finished making the motor mount for the compressor and its up and running.

Now we need to look at downstream analyzing of the mixture. Being downstream obviously means high pressure (HP), thus needing to reduce the sampling flow to a lower pressure.

Rather than buy a high dollar HP regulator, has anyone used a 1st stage scuba regulator converted/modified it to be used on the downstream side (to lower the press) to analyze the misture.

If so, how do you accomplish this, what modification was made, and how was it attached, etc.

I am a machinist by occupation and have at home 2 lathes and a small mill. So machining won't be a problem, even if I need bigger machines - I got access to 'em at work.

Thanks.......carl

 

[omar]

Make sure you take the air sample after the moisture separator. (I sample mine after filtration). An inexpensive ($55) pressure reducer that will take the pressure down to 150 psi can be found here: http://www.scubacompressor.com/shop...d/172?osCsid=9d8de4b8d20615dde6faa6d7ef3bcb4c

You can put a needle valve on this and then run it to the analyzer.

 

[pescador775]

Forget the scuba regulator. You should get a miniature oxygen regulator or something else old fashioned with modular fittings, not the type made with a single complex forging. For example, I bought a used 8 lpm MADA regulator, removed the oxygen yoke and installed a 1/4 inch coupling. In fact, I used the original (chrome) part from the regulator and machined one end. (The other end was already 1/4). Using the brass 1/4 inch npt coupling I screwed the regulator into a T connection on the final filter. The MADA is constant pressure and has a built in needle valve and gauge which I set to 2 lpm with a turn of the knob. The O2 is fed to an analyzer. It is good to 3500 psi but not sure about higher pressures. Fun to play with and necessary for the beginner. I paid 10 bucks for the reg on EBay.

Edit: I looked at the compressor and realized that a coupling was not used; that was for another project, a Scuba tank sampler. For the attachment from the reg to the compressor filter output the only thing that was necessary was a T fitting. The fitting is 1/4 male/male with a male AN-4 (JIC4) leg for the whip.