Check Valve - Need Help Installing on Alkin W31

[pescador775]

No, Hacker, 1/4 NPT used to be pretty common in Germany and was used in the Bauer some years ago. Not sure about current practice. The valve fittings screwed into the secondary coalescers were probably some kind of BSPT or Whitworth. The threaded boss had an extreme taper which locked up abruptly when sealed. There is a BSPT which looks a lot like metric and similiar to ANSI in some sizes. If I remember correctly, the valley angle (notch between thread) of the British pipe thread is 55 deg where metric and US uses 60 deg. I haven't had much luck screwing a 1/4 inch NPT into a Whitworth 1/4 inch size. At least I think that was what I was dealing with. It also could have been one of the Euro 7-1 metric threads. Anyway, I removed the gauge from a DIN tank pressure gauge (tank checker) and tried to install a 1/4 inch NPT fitting into the body and it would only take up a couple turns before it became apparent that it would not fit. I got a machinist to make a fitting that would screw into the gauge body. He had to special order the die. I know the guy has metrics so it was probably British. He said "Whitworth".

 

[realdiver7]

OK everyone, here's an update to my original post with a successful outcome!

The check valve I received was more like 2 inches in length, instead of the 3 inches I was quoted on the phone when I ordered it. I was able to remove the large boss fitting, screw the male end of the check valve directly into the filtration canister, screw the boss fitting into the female end of the check valve, and then screw the coiled tube fitting back into the side of the boss fitting.

I had to use as little teflon thread tape as possible on the male end of the check valve when screwing it into the canister, and I had to seat the check valve as far in as possible into the canister. I also had to rotate the canister just a little on the bottom canister bracket. With all of these minor and tight adjustments, I only had to bend the coiled tubing just a little to make the fitting at the end go back into the side of the boss fitting. The final steps were to leak-test all fittings that were involved in the installation with a thick solution of dish detergent and a little water, run the compressor, and then check for pressurization in the filtration canister once the compressor was shut down. Everything seems to work perfectly!

The above method eliminated having to bend the coiled tubing much, it (barely) allowed just enough clearance for me to place the wooden compressor cover over the compressor, and it eliminated the need for using one or two male/female elbow fittings. I must admit I held my breath as I was tightening the check valve as deep as I could into the filtration canister, as this step had the potential for creating the most severe problems if the valve was overtightened. I also had to be careful not to overtighten the boss fitting on the female end of the check valve, as I had to line up the fitting horizontally to accept the coiled tubing.

In retrospect, I should have waited to receive the check valve before I posted this thread asking for help, but I still appreciate all of the replies and I have learned a great deal from everyone. I have posted pictures of the final installation in my next post below.

Thanks to everyone!

 

[oxyhacker]

I said whitworth threadform, not whitworth thread, that is to say, the 55 degree, radiused peaks and valleys, but not necessarily the thread count that you would find on a whitworth fastener of similar size - the 1/4 BSPT is 19 tpi, while the 1/4" NPT is 18. Pretty close, especially considering they are tapered, so the ham handed machanic will just assume any mismatch is the taper kicking in and never know the difference (unless it leaks, which is where the sealant comes in). Bauers also use BSPP (parallel) threads for most of their relief valves, making BSPP F-to-NPT M adaptors a big seller for Bauer dealers.

A lot of mechanics call any English thread Whitworth, but there are a lot of them which use the whitworth threadform aren't properly speaking whitworth. And the BSP family has been adopted into the metric system as ISO 7-1, so any resemblence is more than coincidental!

No, Hacker, 1/4 NPT used to be pretty common in Germany and was used in the Bauer some years ago.

 

[pescador775]

Realdiver, welcome to my world, seat of the pants flying, LOL.
Pesky

 

[Waterskier1]

OK everyone, here's an update to my original post with a successful outcome!

Please post a pic of your solution

 

[realdiver7]

Waterski1.....in my previous post you'll see that I promised to post pics later today when I got home from work. Well, I'm home from work now and have added the pics below for your viewing pleasure!

Hope this helps others who may want to try this, but please go very slowly and be very careful!

 

[realdiver7]

Realdiver, welcome to my world, seat of the pants flying, LOL.
Pesky

Pesky....yep, it was definitely by the seat of the pants flying!

Thanks for your input!

 

[Hoosier]

Just out of curiosity, the PO filtration is your only filtration appliance. You don't have an extra/additional filtration chamber after the compressor?

 

[realdiver7]

Just out of curiosity, the PO filtration is your only filtration appliance. You don't have an extra/additional filtration chamber after the compressor?

Hoosier....I've researched this subject quite a bit and that is a very good question. I have discovered there are many varying opinions, but the bottom line is that I was told by reliable sources that by using continuous blending (never partial pressure), keeping a close eye on the moisture/CO monitor, and repacking the filtration canister correctly and in a timely manner, that the W31 produces air quality that is OK for blending Nitrox mixes up to 40%. I blend mixtures of 32%-34% normally, but keep it closer to 32% most of the time to reduce wear on the compressor and conserve my O2 supply. So far everything has worked out fine, but I am obsessive about constant monitoring. I'm always open to hear about others' experiences as I am rather new to the home compressor world.

 

[Hoosier]

As you may know, I also have an Alkin AD model with Cbing. However, based on my experience, PO filtration on Alkin doesn't last long. In my case, one repacking filtration only lasts 10 hrs and even a moisture sensor was soaked with more than 20 hrs.

I got the compressor first and added up the extra filtration later (time interval). Before adding up the extra filtration, I have experienced the wet fills many many time. It tells you when you have next VIP, specially on your steel tanks. In addition, For the 2nd example, I have used the chrome plated and brass fittings on the outlet line (after compressor). One of fittings was 90 degree elbow adapter that gives a nice hose routing. When I disassemble all fittings (after compressor) to build the permanent extra filtration (2nd chamber), I was shocked at how much dirty moisture stuff was trapped on the elbow and other fittings (i.e. T fitting). So, immediately I added up the micron filter right after the compressor first. Recently, I switched all fittings between the compressor and 2nd filtration to SS and could see how much the inside fitting is different between before and after 2nd filtration (used more than year).

I can see your intension why you wanted to pressurize the PO though. There is an argument that PO chamber should be unpressurized before the compressor starts. I am NOT a compressor expert, so I don't know the detail mechanism. However, IMHO I don't see any big advantage of pressurizing the PO chamber BECAUSE

1. PO capacity is very minimal so that the pressurizing chamber doesn't give that much extension of filtration life (maybe 1~2 hrs at most).
2. As you know, it takes a very short time to fill PO filtration unlike 16" or 32" chamber. So, you can't save an air on PO. It is a big factor on the bigger chamber.
3. Even though you have PV somewhere, it eventually leaks over time (i.e. 1000 psi drop over one week). My compressor and all chambers (2nd and 3rd chambers) are pressurized and can see the pressure change through each gauge over time (I also asked about this leaking, but it is pretty normal as I got the feedback from the board members).


I don't know your local weather environment, so YMMV though.


Just my 2 bar...