Boosting

[john j]

Regarding the failures on the baby booster.  The first failure I had was a worn our check valve.  I had spare parts and fixed that easily in a few minutes.  The second problem I had was that the pump locked up.  I sent it back and they had to replace the piston, cylinder sleeve and all the valves.  For some reason, it just jammed up and severly damaged itself.  I filter the gas going in, so I don't think I got a piece of sand or other particle in there.  I have no explanation for that problem.  The total bill for that repair including shipping from Canada was only about $130.00, which I thought was quite reasonable considering that they replaced almost all of the internal components of the pump.

Regarding fill whips, I avoid buying fittings and hoses from diving places whenever possible because they are too expensive and many times inferior quality to what I can get for industrial applications.  Some things like yoke and DIN fittings are only sold through dive shops, so you have to go that route on those.  However, many of the fill whips sold through dive shops have carbon steel ends.  These always rust inside and are thus a major oxygen fire hazard because they send rust particles through all your valves and fittings.  For whips, I use electrically conductive CNG (compressed natural gas)  hose with stainless steel ends.  I get that through a local Parker distributor called Quest Engineering.  This hose is custom made with whatever ends you ask for.  I get stainless steel 1/4 male NPT ends with strain releif.  However, you must special order such that they do not use any lubricant when they make up your hose assemblies.  They will gladly do that but you have to ask for it specifically.  If you do not ask for that, they will use hydrocarbon oil as a lubricant when they make up your hoses and there will be lubricant trapped on the barb inside the hose fitting.  You will find that unpleasant when you pump oxygen through it.  The CNG hose is super tuff and lasts for years-it absolutely blows away anything I have ever seen from the dive industry and Parker Engineers approved it for my application, so I trust that it is OK for what I am doing.

For things like gauges and pipe thread fittings, I also get them from Parker via Quest Engineering.  I like brass fittings because stainless steel threaded to another stainless steel fitting tends to gall during assembly if it has been cleaned for oxygen service.  What I mean by "gall" is that the threads cold-weld together and you can't ever get them apart again.  I have tried to find an effective oxygen compatible anti-galling agent but I don't think there is one.  I dont really like pipe threads becasue they are hard to get gas tight and they always create metal shavings when they are assembled (not the best for oxygen applications), but they are so much cheaper than the alternatives, that I give in and use them. 

I don't have part numbers with me right now, but if you want more detail, I would be glad to provide it.