high pressure hoses

[cclark]

I'm setting up an high pressure fill and O2 transfer station, and sent out a request for quote for some high-pressure (5000 PSI) hose assemblies. They were available at around $65 ea.

I can get 5000 PSI neoprene hydraulic hoses for about $10. Neoprene is rated as a"prefered" material for O2 use at

http://www.efunda.com/designstandards/oring/oring_chemical.cfm?SM=none&SC=Oxygen, Cold

.

So, will someone please tell me why I should pay 650% more for a hose from a dive equipment supplier? (Naturally, the hydraulic hose assemblies would require careful cleaning).

 

[roakey]

Hydraulic hoses are typically porous to gas, they're only "liquid-tight".

Roak

 

[omar]

One of the most common cause of hose failure is misapplication.

This is comparable to using a garden hose for a snorkle.

omar

 

[cclark]

Thanks for your input on this matter.

I'll be buying hoses which are sold as air fill hoses (since my original post I got another quote for $45, which I don't choke on), and also some hydraulic hoses to test roakey's conjecture that they are "porous to gas", which I DO have a bit of a hard time swallowing. I'm also getting some quickcouplers rated for high pressure air and some rated for hydraulic to compare their construction and behavior with gas (again at about a 5 to 1 price ratio). I will report in this thread as to the regimen and outcome of these tests.

Omar's statement

"This is comparable to using a garden hose for a snorkle"

brought back memories of the time when, after a long work day, I drove out to an isolated beach for a snorkel, only to find my snorkel had somehow disappeared from its customary spot in my truck. Fortunately, I had a roll of 1/2 ENT (Electrical Nonmetallic Tubing, a type of semiflexible pipe used in construction wiring) along, which I quickly bent into an "emergency" snorkel. It wasn't ready for prime time, but sure filled the bill that day!!!

The point being that cross-application is not always "misapplication". Often it's a solution with distinct advantages.


Yrs,

Chris

 

[roakey]

cclark once bubbled...
...and also some hydraulic hoses to test roakey's conjecture that they are "porous to gas", which I DO have a bit of a hard time swallowing.

One of the shops here in town has a bank that's located in a trailer in the parking lot (so they can take the bank on the road) with a fairly long (50') hose run into the shop. When they got their hoses replaced about a year ago the vendor replaced the hose with a hydraulic hose. It hissed along its entire length.

Hydraulic fluid is much more viscous than gas, on the order of magnitudes. The hoses can be made out of a more porous material and not leak hydraulic fluid.

Roak

 

[joens]

I am at work right now at the shop and I am looking at the Caterpillar hydraulic hose compatability guide It indicates that the standard hoses are not compatable with air they do make some hoses that will work with air but you need to request those particular hoses . the standard hose you will get if you ask for a Hydraulic hose is not recommended for compressed air. none of them are recommended fo oxygen. Do not waste your time and money buying a standard hydraulic hose intending to use it for air.Any place that sells Hydraulic hoses SHOULD have a chart comparing the compatability of different hoses .If you are going to go that route at least get a hydraulic hose that says it will work for air .Also the hose seeping air may not be easily noticable at first but then you may see a bubble start to form as air leaks through the inner layers but not the outer layer..
another problem is that some of the hoses that will work with air arent rated for high enough pressures .
joens

 

[joens]

I just thought of something else .most all places that make hydraulic hoses lubricate the end of the hose before sliding the fitting on [it is a tight fit] .I have seen them do everthing from spray WD-40 in the end to dip the entire end of the hose 6" deep in a bucket of hydraulic oil . definately not oxygen compatable and I wouldnt want a slug of oil shot into the first tank I filled.If you are still thinking of trying a hydraulic hose .try to get them to make it without oiling the ends .
joens

P.S. let us know which of the 2 failure modes you experience hissing the entire length of the hose or bubbling and popping the outer layer of hose

 

[omar]

all right a better analogy...

It is like using garden hose for an automobile radiator hose.

omar

 

[nickjb]

omar once bubbled...
all right a better analogy...

It is like using garden hose for an automobile radiator hose.

omar

Ooh... I've done that. Sorry, I'm not helping , am I?

 

[roakey]

The hydraulic hose that the dive shop got had perferations in the outer jacket so it didn't bubble. Why the outer jacket had perforations I don't know, but it was a regular pattern so obviously part of the design.


Roak