Normally I do not write about the toys that have found the way to my office or home through a simple purchase. This is different as I think it may be of interest to some the damned fools who dive rebreathers and are even more foolish to compress oxygen. I do not recommend that anyone do either of these dangerous activities, sending usefull parts of your body to the red bag waste at your local hospital or leave your family without benefit of your important presence. Is this the only booster pump?...no...is it the best booster pump?....probably for me because of the simplicity.

Ever since I discovered Airspeed Press books on Oxygen systems and booster pumps, I had a little itch in the back of my head to bring my oxygen tanks up to 200 BAR rather than the 150 BAR or less from my cascade. This would be especially important for my little .8 liter RGU tank. At 200 BAR it holds 160 liters of oxygen good for a couple of hours (with a safety factor) while at 150 BAR (when the top tank of the cascade is full) it only holds 120 liters of oxygen. I considered building a booster...with the help of a couple of great mechanics who work for me. Instead, I just went with a larger tank. Then I went to DEMA and fell in love with the RIX Compressor little booster the MICROBOST 115. At 49 pounds, with an ac power cord and simple operation, AMX card out, I was ready to spring for the unit, at the show. Then I learned the sad truth...the unit is not designated for 200 BAR in the US but only 150 BAR or so. What could be the difference between the units? Inquiring minds wanted to know.

Polite and persistent inquiries dredged up the rumor that the only real differences between the European unit and the one at DEMA are the 1/4 inch NPT outlet and inlet fittings, 110 volt motor, and the setting on a pressure switch tucked inside the base. RIX does not currently certify or recommend the use of the unit to 200 BAR in the US. Did I plan to cheat, invalidate the warranty, and take my life in my hands? Of course not. I really only wanted to make sure that I got the full 150 BAR on my tanks....

Mine arrived last week and I started to play. Having spent $2500 on the compressor (I do not know if that was a show special, a high price,or a low price) I had some additional parts and pieces to add that cost less than $100.

The first step was to attach an adaptor to each of the 1/4 inch npt fittings at the end of the system. I decided to use a 1/4 inch plastic tubing for the low pressure side so I added an elbow nylon NPT to barbed fitting and attached some tygon tubing to the barbed side. To eliminate the need for multiple whips I decided to add a scuba block to the compressor. It took a little offsetting with a union and nipple from the fitting boxes, but only a few minutes after I found the one I wanted and cleaned it with simple green. Rix suggests that you flush the plastic inlet tubing with pure oxygen. Now with the plastic tubing connected to a regulator set at 20 psi (the max is 25) and the high pressure system attached to the tank to be filled, I was ready to go.

As I gaze across the room at the little RGU tank and the oxygen cleaned 200 BAR Catalina Pony Bottle that fits my new smaller chestpack I just made, I am tempted to open the base of the booster by removing the little rubber feet...what the hell, I only want to look at the pressure switch. Mankind is a naturally curious animal...that is why we came down out of the trees.

I won't change anything.......I promise....