When I was a diver I never really gave much thought to Oxygen Regulators. Most of the regulators we had were 2 stage and I like everyone else thought if a single stage is good then a 2 stage is twice as good. I never questioned what we were using because we have been doing it like this for years so this must be the best tool for the job...

After I went to Oxylance to develope and manufacture the AQUA EXO and AQUALANCE underwater cutting rods I became involved in all of the products that Oxylance produced. We build a burning bar that is a giant model of a wire filled underwater cutting rod. These rods range from .675" od to 1.05" od and are 10'6" long. They require from 35 to 100 cubic feet of oxygen per minute or 2000 to 6000 cubic feet per hour. Our customers were using standard oxygen regulators with 3/8" hose and in most cases they were not getting the required flow of oxygen. We began a series of burning test with different regulators to determine which regulators worked best and what could we do to improve Oxygen flow.

We found a regulator manufacturer that was willing to work with us to determine what could be done to improve oxygen flow. The first thing we found while working with the regulator manufacturer was that for high flow situations a single stage regulator out performes a 2 stage regulator. The engineer that we were working with explained it to me in lot of technical terms but I can break it down into a very simple explanation. The first stage reduces the pressure down from the supply pressure to about 500 psi, the second stage reduces it down to the desired pressure setting. Because of the size of the orifice between the first stage and second stage it creates a huge restriction thus reducing the volume of gas that the regulator can flow.

After showing the engineers our burning bars and what flow we needed they designed a regulator for us that had very large ports inside a single stage regulator and they designed it with a 1/2" port on the outlet side so we could go up to 1/2" hose. The results was a single stage regulator that supplies 11,000 cubic feet per hour through a 1/2" hose at up to 250 psi. During the testing they showed me all of their flow benches and I asked a simple question. You are flowing oxygen against atmospheric pressure, what happens when you flow pressure against pressure. I explained the situation with underwater cutting where you had to set the regulator at 100 psi over bottom pressure and all about the pressure changes as a diver goes deeper.

The engineer who was doing all of the flow test developed a flow bench where he could set back pressure to duplicate what the regulator would be working against at various depths. We tested several regulators that are common to the commercial diving industry and found that at depths as shallow as one atmosphere, 33 fsw the flow rate of the regulators being used by divers was reduced. At depths over 150 feet one 4500 cfh regulator would only flow 2400 cfh and at 300 feet it was down to under 1100 cfh. Most of these regulators have a 1/4" outlet port feeding a 3/8" hose which is a huge restriction right from the start.

We then designed a regulator for the underwater market. Starting with the same body used for our topside regulator with 1/2" ports they worked on a diaphram and springs to push the regulator out to 500 psi. When completed the testing showed that this regulator was capable of pushing 7000 cubic feet of oxygen per hour with a back pressure equal to 700 fsw. On the surface flowing against atmospheric pressure it will flow 12,000 cfh. We have now been selling this regulator for several years and everyone who has tried it are amazed at the flow rate and the price. This regulator sells for around $300.00 where other companies charge over $450.00 for a regulator that flows about 1/3 of the volume this one produces.

This regulator is available from our distributor Bay Tech Industries. The part number is REG-5-500.

Greg Cain aka Papa Smurf