Demand valves on eBay

[CHfather]

I just posted this in a message to Vickle, but just in case . . .

I see that there are 9 used demand valves for sale at ebay.  It looks sketchy -- sold as is, no returns.  $100 plus $10 for regular shipping.  Can't say if it's a worthwhile risk or not.  (If you go this way, you'll need to have a DISS fitting on your regulator. See below)  http://www.ebay.com/itm/Used-LIFE-SUPPORT-PRODUCTS-INC-DEMAND-VALVE-SWITCH-L063-05R-WITH-HOSE-AND-MASK/161085791809?_trksid=p2045573.m2042&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D27%26meid%3D1468536138082648837%26pid%3D100033%26prg%3D1011%26rk%3D2%26rkt%3D3%26sd%3D300946941177%26

[alleyoop]

Good find CHf!

[diamondmaker]

They certainly look well used...

I found some specs, they are 40 lpm output and retail for over $250.

[ThatHurtsMyHead]

Good find!

Looks like a high pressure flare fitting on the hose.  It takes a special 1st stage regulator that mounts on the tank to fit it.  Just want to make sure anyone buying one knows it won't fit a regular O2 Medical tank (without the additional regulator).

[CHfather]

Jeff, can you say more about that special regulator?  What it's called; where to get one; etc?  Thanks.

[diamondmaker]

Just a regulator with a DISS valve.

Edit: To clarify, regulators reduce the 2500-3000psi down to a usable... say 200psi. When you turn the knob it restricts that 200 psi to the flow you want. The DISS connection should not be governed by the knob... it should deliver the full 200psi directly.

[diamondmaker]

This one does both:

http://www.amazon.com/REGULATOR-Closeout-Compare-SuperFast-Shipping-really/dp/B004SBSMYI/ref=sr_1_57?ie=UTF8&qid=1379973336&sr=8-57&keywords=oxygen+regulators+medical

This one only does the demand valve:

http://www.amazon.com/Oxygen-Pressure-Regulator-Medical-Valves/dp/B006O8MBAO/ref=sr_1_50?ie=UTF8&qid=1379973464&sr=8-50&keywords=oxygen+regulators+medical

You will need caps to plug any unused high pressure DISS connectors if it doesn't come with any. (again easy to find).

[ThatHurtsMyHead]

Spot on DM!

That first one in your post looks like a really good deal.  Paired with the demand regulator it could make O2 go a little further.

[Racer1_NC]

You will need caps to plug any unused high pressure DISS connectors if it doesn't come with any. (again easy to find).

I never have had problems with them uncapped. YMMV

[diamondmaker]

Actually I just read an add for one that said the DISS valves self seal... just trying to cover all the bases.

[CHfather]

Thanks, guys.

[Marc]

Just a regulator with a DISS valve.

Edit: To clarify, regulators reduce the 2500-3000psi down to a usable... say 200psi. When you turn the knob it restricts that 200 psi to the flow you want. The DISS connection should not be governed by the knob... it should deliver the full 200psi directly.

I would add that standardized DSS port output is 50 psi.

Marc

[Professor_Tanaka]

I buy demand valves off ebay regularly.  They range from great shape to train wrecks, with most being in the middle or lower end.  Most need the exhalation valve replaced at a minimum.

The most common issue is that many are really noisy... annoyingly noisy... due to wear on some internal parts.

One issue with the 40LPM variants... that is 40LPM when constantly on, which is not how a demand valve works.  In other words they deliver less than the 25LPM touted as being the CH need when breathing from it regularly (say 50% cycle). 

It is easily fixed... the intake fitting is where the 40LPM limit is.  You take it off, drill it out slightly (it is very soft metal), clean it up and replace.

[Professor_Tanaka]

On a side note, scuba second-stages perform basically the same function as demand valves, and are plentiful and cheap on ebay. 

Perhaps I will look into the pressures involved at each stage.  If they look compatible I might figure out the fitting adapters needed to hook these up to a medical O2 regulator. 

[diamondmaker]

I researched scuba equipment a while back and it seems that special regulators are used for high O2 concentrations. They need to be O2 compatible for reasons like (I am guessing) oil used in assembly and other possibly flamable components when pure oxygen is used. They are available, but more expensive. On the other hand, I have seen reports of people using the standard regulators without a problem? Gonna take more research for sure.

[Marc]

For a low budget, reliable solution, the welding O2 regulator is hard to beat. Yes, it fits on all welding tanks and all large medical O2 tanks with a standard CGA-540 fitting. You can also get an adapter to use your welding regulator on a little medical "E" tank with the CGA-870 "yolk" fitting.

A welding regulator can easily outrun the maximum breathing rate of several people at the same time. I found that I need 45-60 lpm for the first 30-90 seconds in order to get the shortest possible abort time. Once I understood how to breath that fast and deep, I cut my abort times in half and never had a real headbanger again. THAT is worth gold to me.

Some folks claim that a demand valve uses less oxygen than a conventional regulator. This is not true. If you adjust the regulator output so that you have the O2 you need when you breath in, and the bag doesn't over inflate when you exhale, there is no waste. You can't save anything if it isn't being wasted.

I'm not against demand valves. They are indeed convenient - just expensive for some of us.

Just my 2 cents in our world where pennies are worthless.

Marc

[Vickle]

They won't ship it to me in Canada.  lol 

[CHfather]

Finally set up and tested the demand valve I bought from the eBay site at the top of this thread.  Worked great. I suppose that's no assurance that the other ones will -- there are still 6 available -- or that it will continue to do so, but I see that the seller has 100% satisfaction ratings at eBay.  The mask is really comfortable, too.

http://www.ebay.com/itm/Used-LIFE-SUPPORT-PRODUCTS-INC-DEMAND-VALVE-SWITCH-L063-05R-WITH-HOSE-AND-MASK/161085791809?_trksid=p2045573.m2042&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D27%26meid%3D1468536138082648837%26pid%3D100033%26prg%3D1011%26rk%3D2%26rkt%3D3%26sd%3D300946941177%26

[Bejeeber]

COOL.  [smiley=thumbup.gif]  8-)