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Post by nikeajax on Aug 28, 2012 15:09:28 GMT -8
I was looking at my Healthways tank valve and it looks like it has a HP outlet that you could put an SPG on: am I mistaken? And no, I'm not talking about the burst-disc either because that's on the other side. I think one of my USD valves is like this too. What's the deal with the Healthways Airflo reg? www.vintagescuba.com/hw/hwairflo1.htmlIs this an early DIN: sorry I know NOTHING about them. It strikes me as odd, that it's a SH with no SPG port: their Scubair is older and it has one... Thanks, Jaybird |
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Post by duckbill on Aug 28, 2012 16:27:58 GMT -8
Yes, you have it. That port is for a SPG.
The Airflow was their attempt to make a single hose reg as small and streamlined as possible. It also made it mandatory to use their proprietary cylinder valve. As you can see in the photos on that site, the 1st stage screwed directly into the valve, but the valve is also usable with standard yokes, unlike a DIN valve. I have the valve on some of my tanks (the twin 50s in my avatar has just such an outlet), but haven't landed an Airflow yet. Not a priority at this point.
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Post by nikeajax on Aug 28, 2012 16:52:38 GMT -8
Excellent, thanks buddy; I'll be using that with my Scuba Deluxe then  On a side note; I was playing around with my Scubair-300 and thought I had a back-up for it with a Scubastar that Dave gave me--DOH! That's a NO-GO! Scubastars are tilt-valves... I have ZERO desire to learn what happens when you combine those two. I remember John saying never to do that, and, well, his word is more than good enough for me... Jaybird |
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Post by SeaRat on Aug 28, 2012 18:38:45 GMT -8
Jaybird, it's not that you cannot combine the tilt valve with a Scubair 300, because it can and has been done. What I was saying is that if you put a tilt valve second stage on a first stage, you need some kind of overpressure relief valve in the system; otherwise there is no way to vent pressure if the first stage malfunctions. The Scabair 300 downstream second stage will also act as that kind of overpressure relief valve, so the two can be combined. It's just that you need to know the reason why there could be a problem.
John
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Post by sitkadiver on Aug 29, 2012 9:03:41 GMT -8
So here is a random question....
Can you put a splitter on the LP port, run the reg off of one splitter port and put the over pressure releif valve in another. Shout leave you with a 3rd port for a bc or octo if you wanted.
And I am asking this on the assumption, that your 300 has only 1 lp port and 1 HP port....
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Post by nikeajax on Aug 29, 2012 9:20:12 GMT -8
More futsing this morning... I thought I'd see if any of my LP diaphragms fit my Healthways, nuttin', but I did find that a USD Calypso will drop right into a Dacor Olympic though.
Question: how critical is diaphragm height? The USD diaphragm rests right on top of the levers on the Olympic, whereas the Dacor has a definite gap, I could tap it and hear it hitting/making contact, then spring back up. It seems to me that eliminating the gap would make it breath better, more sensitive--right?
Jaybird
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Post by duckbill on Aug 29, 2012 13:42:36 GMT -8
Question: how critical is diaphragm height?......It seems to me that eliminating the gap would make it breath better, more sensitive--right? Jaybird Kind of two separate questions. A diaphragm with a higher dome shape may be worse than one with less of a dome shape, but a slight dome shape may be better than a flat diaphragm. Then there are bellows, and materials, and.... But, I think I understand what you are asking by the second part. My answer would be, "Yes, but most likely not noticeably so." The reason being that it usually takes very little water pressure to close up the gap. Of course, the larger the diaphragm (as in most double hose regulators) the better in this regard, all else being equal. As soon as you submerge, the diaphragm will be touching the lever. |
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Post by nikeajax on Aug 29, 2012 16:14:32 GMT -8
DB, thanks for elaborating on that, so... since the second stage needs to be adjusted anyway, I don't see why the USD diaphragm can't be used instead of the Dacor if an when the old one goes bad...
I've been doing some research as to how to make stuff out of silicone, molding... I think I need to make a dummy out of hard plastic to spec first, then create a resin mold from that and that way it can't lose shape...
Jaybird
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Post by nikeajax on Jan 2, 2013 9:25:20 GMT -8
Does anyone know the IP for the Scubair? I understand that you use shims to adjust the IP: just out of curiosity, how many PSI does each shim ad? What would be the max IP I would want to use?
Jaybird
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Post by SeaRat on Jan 2, 2013 10:28:02 GMT -8
Jaybird, it depends...
Why? Because it depends upon which Scubair your are talking about. The original Scubair is a tilt-valve second stage. I have reviewed Fred Roberts book, Basic Scuba[/B], and he does not mention the interstage pressure for the Scubair. He does discuss the overpressure relief valve, and it's setting is either 110 psig (Scubair) or 1/4 turn below a leakage of 200 psig (Scuba Star; this should also be around 110 psig). My thought is that the tilt valve interstage pressure is between 90 psi and 110 psi.
Realize that this is an unbalanced system, and there will be a difference in the interstage pressure due to the cylinder pressure fluctuation. If my memory is correct, the interstage pressure on an unbalanced piston first stage varies from high to low as the tank pressure varies from high to low. So at full tank pressure of 2250 psig, you will probably have around 110 psi interstage pressure while at 500 psig (low cylinder pressure) you will have about 90-100 psig interstage pressure. You can check this out with your regulator pretty easily. This is the opposite of a diaphragm spring-biased first stage such as the Dacor Dart or the DA Aquamaster, which have the higher interstage pressure at lower cylinder pressures.
Concerning the use of shims, this may not be an advantage because it boosts the interstage pressure. If you have a tilt valve, boosting the interstage pressure may make the regulator harder to breath. Usually on a tilt valve, there is very little venturi action, and the higher interstage pressure will make the cracking effort higher, because of the upstream valve design. As I recall, the shims are about 5 psig boosts, and I use three of them on my Scubapro flow-through balanced piston design. But the Healthways piston is unbalanced, and use of shims will cause the range to shift up 5 psig or so. So making the interstage pressure higher may or may not help. It depends upon the second stage design, and if it is post 1961 or so and has a downstream design, it may help.
'Hope this makes sense.
John
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Post by nikeajax on Jan 2, 2013 12:15:28 GMT -8
John, yes, that made a lot of sense  It'll be a while probably 'til I can get my Scubair-300 in the water, but I just thought I should ask while it was on my mind... Gosh, it's a good thing I asked, as I thought it should be higher--YIKES! A while back while browsing ebait, I saw a Scubair, but it was a tilt-valve  I was under the impression that as soon as they changed the name from Scubastar to Scubair, they were no longer tilt-valves: could this have been two of them cobbled together? Jaybird |
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Post by nikeajax on Jan 2, 2013 15:19:50 GMT -8
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Post by SeaRat on Jan 2, 2013 16:37:02 GMT -8
Jaybird, no it wasn't until about 1962 that Healthways started making their downstream second stages, and that covered all the line. The Healthways Scubair actually went through a number of changes, and started out as a diaphragm first stage with a tilt-valve second stage if my memory is correct. It then progressed to the first stage being a piston type, but having a bypass that allowed a constant reserve mechanism or no reserve, based upon the restrictor orifice. If you get a later Healthways, with a rubber exhaust tee and the nylon clip that holds the cover plate on, it will be a downstream second stage with a much-improved diaphragm. I got one simply for the diaphragm, and when I put it on my Scuba Star tilt valve, it breathed a whole lot better. Here's an example: www.ebay.com/itm/Vintage-ScubAir-300-Healthways-Scuba-Regulator-Set-Lot-1-of-2-/190777329050?pt=LH_DefaultDomain_0&hash=item2c6b37059aJohn |
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Post by sharkskin on Jan 2, 2013 21:10:38 GMT -8
Hey, thank you all guys, especially Jaybird and John for bringing this kind of regulator talk to the surface. I have always wonder how these Healthways single hose regulators perform and you're surely clarifying some of my questions. Are they good breathers overall?? easy maintenance?? Can you use them with 3000psi? I know! Rookie questions but...  Thanks all! Harry |
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Post by SeaRat on Jan 2, 2013 22:33:22 GMT -8
Sharkskin, the Healthways regulators were extremely easy to maintain. The later models (1970+, with a downstream second stage) could be used on 3000 psig tanks, and the U.S. Navy tested them in 1975. Unfortunately for Healthways, they did not pass the Naval Experimental Diving Unit (NEDU) tests, and were not approved for U.S. Navy use. They had below average inhalation resistance, just meeting the Navy requirements at 1400 psig (Scubair II) and meeting the inhalation specs pretty well (Scubair 300), but way out of specs at 200 psig and out of spec for exhalation resistance. Here are the results: archive.rubicon-foundation.org/xmlui/handle/123456789/3435 archive.rubicon-foundation.org/xmlui/bitstream/handle/123456789/3435/NEDU_1975_05.pdf?sequence=1I started out with a Healthways Scuba Star (my second regulator, ever), and then switched to an AMF Voit Fifty Fathom single hose regulator (the equivalent of U.S. Divers Company orginal Calypso regulator). I stayed with USD regs thereafter, until I got interested in the history of these Healthways regulators. I now have a collection of them. Their exhalation valve opening was small, and that kept them from any possibility of U.S. Navy approval. Their diaphragms were indestructible, but also not too flexible. This meant that while these were fairly cheap, dependable regulators, they were not the best breathing regulators. If you want to see other regulator tests, do a search in the search box on the first link above. The NEDU produced a number of very interesting tests. John |
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It'll be a while probably 'til I can get my Scubair-300 in the water, but I just thought I should ask while it was on my mind... Gosh, it's a good thing I asked, as I thought it should be higher--YIKES!
I was under the impression that as soon as they changed the name from Scubastar to Scubair, they were no longer tilt-valves: could this have been two of them cobbled together?
