Plumbing assistance please

[Doc Harry]

Gentle with me please, it's my first time.

My compressor arrives on Friday: Alkin W31 with LF 32-inch filter. Also got 3 x 440 cubic-foot bank bottles.

I'm been trying to plan the plumbing. Maybe the answers to my question will be self-evident once the compressor is unpacked.

I understand that you want to keep the filter towers pressurized so that you don't have to repressurize them every time you turn on the compressor. Sooooo.....

How do you keep pressure on the filter towers when you turn off the compressor?

How do you keep pressure on the filters when you bleed off the whips?

 

[Doc Harry]

How do you keep pressure on the filter towers when you turn off the compressor?

How do you keep pressure on the filters when you bleed off the whips?

PRIORITY VALVE???

 

[CraigAClark]

If you use the machine on a daily basis, the pmv will keep pressure in the tower. They sort of act like a shut-off valve. AE's pmv will eventually leak out if there is no back pressure down stream. LF's, in my experience, are "no loss" and I use them with our RH monitor. So far with excellent results. You can also put a shut-off valve down stream and close it when you are done filling.

Your machine's filtration should already be equipped with a pmv at the outlet.

Are you setting the storage up as a cascade or bulk? If they are HC-4500 bottles, do you have a regulator down stream to prevent over filling should your attention be drawn away?

Craig

 

[Doc Harry]

If you use the machine on a daily basis, the pmv will keep pressure in the tower. They sort of act like a shut-off valve. AE's pmv will eventually leak out if there is no back pressure down stream. LF's, in my experience, are "no loss" and I use them with our RH monitor. So far with excellent results. You can also put a shut-off valve down stream and close it when you are done filling.

Your machine's filtration should already be equipped with a pmv at the outlet.

Are you setting the storage up as a cascade or bulk? If they are HC-4500 bottles, do you have a regulator down stream to prevent over filling should your attention be drawn away?

Craig

I was wondering how to prevent overfilling. How do I prevent overfilling? I plan to be there at all times anyway since I will be doing continous blends.

 

[JBRES1]

You would use a pressure regulator and a pressure gauge You set the maximum pressure you want to go out to your dive cylinder, and fill away.
Here is a link.
Adjustable Regulator [ REG-6000 ] - August Industries for Bauer Compressors, Davey and Worthington parts and supplies

Jim Breslin

 

[Doc Harry]

You would use a pressure regulator and a pressure gauge You set the maximum pressure you want to go out to your dive cylinder, and fill away.
Here is a link.
Adjustable Regulator [ REG-6000 ] - August Industries for Bauer Compressors, Davey and Worthington parts and supplies

Jim Breslin

THAT'S what I've been looking for. I used one in Florida, didn't know what it was called.

 

[rjack321]

You need alot more than just a regulator to not overfill unattended tanks.

If you are continuous blending you will need to add a magnetic starter to be sure if there is a power hiccup that the compressor does not restart. If it does it will go boom with the 100% O2 which has filled the mixing stick.

You also need autodrains.

Really you should not continuous blend unattended. I walk away for brief periods (3-5 mins) to go get a drink, pee, or roll the garbage down the driveway. But that's about as long as you want to leave something like this operating IMO.

 

[pescador775]

Harry, I don't have much to add. Make sure your new Alkin is equipped with back pressure valve, some aren't. The BP (PMV) valves that I use also act as check valves so if yours is similar it should prevent back flow from the tower into the compressor filter. I wouldn't depend on a BP valve to prevent leak down at the output. Tighten the valve on the fill armature, and the big tower should hold pressure well enough. As to the pressure regulator, a nice addition but not absolutely necessary. If it gives some assurance of safety go ahead and get one. An alternative would be installation of a small, adjustable relief valve to the fill device but operation might not be as convenient in your setup. I use a lot of custom stuff made from military surplus equipment. So, for purposes of filling (boosting) oxygen tanks I drilled and tapped the fill manifold and added a small Kidde relief valve set to 2400 psi. This just acts like a compressor relief except the valve is easily adjusted if needed. My old Bauer doesn't have the mojo to over fill HP tanks and when filling LP's I just keep an eye on it. A storage cylinder is different, higher flow rate and all so maybe you do need some kind of safety. A flow restrictor might be nice. Basically, this is a metal disc with a small hole, like #68 drill size placed in line. If the high pressure regulator or tower is flow restricted you are already there, probably. I don't know much about HP regulators. You would need to consult with somebody on that one, eg if flow restriction is built in. The actual flow depends on head pressure and tank pressure and that would figure in.

If you pump a lot of gas a few bucks could be saved by self packing the big tower. However, then it would also be good practice to install an in-line micronic filter. These cost about $70. The reason has to do with filter media dust. Some sticklers hold that this dust has to be essentially eliminated. Dacron pads do a good job but there is the assurance thing. Plastic cartridges usually include a micronic element of some kind so no device in-line needed.

 

[Scuba Duck]

I make an auto shut-off valve you can wire into your compressor. It only opens when the compressor is running, and secures the flow of oxygen to your blender when the compressor turns off. Pictures and schematic of how it incorporates into the system is available here:

Rubber Duckie Designs Nitrox Safety Valve

 

[pescador775]

A couple years ago, I disassembled a common single stage oxygen regulator. This is a chrome plated medical type I bought on EBay. I put the body in a drill press and drilled/tapped a 1/4 NPT into the bottom, opposite the flow gauge. Into this hole was installed a pressure relief valve, the kind that are used on air tool type shop compressors, you know, the Sears & Roebuck kind. Originally, the valve was set for 100 psi. I adjusted it much lower to correspond with the oxygen regulator's internal pressure that would produce a flow rate corresponding to 40% oxygen content (EAN) with my compressor. Later, I decided that the vent rate was a little slow so I scrounged up a softer spring and installed in the relief valve. Now, when the O2 goes above 40%, this little relief valve blows off the excess oxygen with authority.

Why this? Well, if uncle Verne happens to turn the oxygen regulator too high, the relief prevents hazardous levels of oxygen from entering the stik. It also protects against consequences of regulator failure.

It works because the "flow" gauge on the regulator is really a pressure gauge which operates in the range of 0-60 psi or 100 psi depending on model. Installing a pressure relief valve in the same circuit is a no brainer at 10 bucks total cost. If my regulator was the 100 psi type instead of 60 psi, that softer spring would not even have been necessary.

There is a discussion here:http://www.scubaboard.com/forums/do-yourself-diy/111955-oxygen-regulator-safety.html