300 bar to 200 bar DIN adaptor?
- Thread starter Rhone Man
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OK, egg-on-my-face. Turns out I'm am not trying to connect a 232 BAR regulator DIN (male) to a 300 BAR DIN tank (female). All of my 4 DIN regulators have 7 thread "300 BAR DIN" connectors. 2 of the regulators connect leak free "as is", and 2 leak. One of the leaking ones (the XS Scuba Sea Air) is all factory spec and dive shop installed. So I've come to the conclusion that all "300 BAR" are not the same.
Yes I did consider and discard that as a valid concern. The regulator is held in by the fully inserted DIN screws and an o-ring failure only decreases the risk of the regulator launching itself at my head (leaky o-ring = less pressure on the connector) and if the o-ring does leak the DIN valves all have a air pressure relief hole that points to the side - and that is where the air is going when they do leak. If the o-ring goes it will be very noisy until I close the valve and then I use my alternative tank to calmly and slowly abort my dive.
Yes I did consider and discard that as a valid concern. The regulator is held in by the fully inserted DIN screws and an o-ring failure only decreases the risk of the regulator launching itself at my head (leaky o-ring = less pressure on the connector) and if the o-ring does leak the DIN valves all have a air pressure relief hole that points to the side - and that is where the air is going when they do leak. If the o-ring goes it will be very noisy until I close the valve and then I use my alternative tank to calmly and slowly abort my dive.
Can we see pictures of the end of the DIN fitting (into the valve) for all of the regulators? I am not aware of any difference between 300 BAR regulator DIN fittings (or 232 BAR DIN except the extra threads on 300 BAR which will not create a leak) so I am now curious. I assume you have checked the O rings to ensure they are all ok and all the same size (perhaps 2 regs have incorrect O rings, sorry for telling you how to suck eggs)
The only fittings I am aware of in 300 BAR that are different are DIN filling fittings (for a compressor) as compared to 300 BAR regulator fittings. The compressor fill fittings have longer fittings in the end to prevent them from being used onto a 232 BAR tank thus potentially filling it to 300 BAR. The extra length means they will only seal on a 300BAR valve and not a 232 BAR valve.
Peter69_56, Yes I can send pictures, and those are good thoughts. Awap had a great link (above) that explains the differences between the 232 and 300 BAR fittings. Since it turns out mine are all 300 BAR I don't have a physical example to compare the two. Might be a day or two before the regs and my camera have a chance to meet :-D
halocline
Contributor
This is hilarious. It takes quite an imagination to compare a space ship with a scuba tank. Well, I guess they're both cylindrical....
---------- Post added November 20th, 2014 at 10:09 PM ----------
The only DIN fill whips that I've seen look exactly like the DIN fittings on regulators, which makes sense because they mate with the valve exactly like regulators. These fittings are the 300 bar length (7 thread) and fit both the 200 and 300 bar valves. So are you talking about a different kind of fill whip? I'd like to see a photo of what you are talking about if you can find one.
Did some measurements and experiments and where (but not why) the problem is. I took the Sea Air DIN kit off the regulator.
and inserted part 37 with o-ring 36 into the tank valve. It seemed to seat well. I then screwed in part 33 until it was as far in as it would go. At this point I could move part 37/36 about a millimeter in and out. Which incidentally coincided with some earlier measurements. I then took a suitable o-ring (about a 116 or so) and slide it on the part 37 before sliding part 33 over 37 and screwing it back into the valve. Snug as a bug in a rug. Next was to re-install 37/36/33 and the extraneous o-ring to the regulator and pressure test. Perfect!
So why is the brand new 300 BAR male DIN assembly a millimeter too short for the older 300 BAR female tank valve??? Easy enough to fix, now all I need is to find a brass spacer to fit where I have the extraneous o-ring. It isn't an airtight connection, just a mechanical spacer. My original 'fix' involved both an extra airtight seal and a mechanical spacer. This is so much cleaner and not in a place it can fall out and get lost. Just using the o-ring as the spacer would probably work, but that even makes me a little nervous.
This is the ScubaPro universal kit. It is the one that sealed "as is", but it is marked to show where I added the spacer.
and inserted part 37 with o-ring 36 into the tank valve. It seemed to seat well. I then screwed in part 33 until it was as far in as it would go. At this point I could move part 37/36 about a millimeter in and out. Which incidentally coincided with some earlier measurements. I then took a suitable o-ring (about a 116 or so) and slide it on the part 37 before sliding part 33 over 37 and screwing it back into the valve. Snug as a bug in a rug. Next was to re-install 37/36/33 and the extraneous o-ring to the regulator and pressure test. Perfect!
So why is the brand new 300 BAR male DIN assembly a millimeter too short for the older 300 BAR female tank valve??? Easy enough to fix, now all I need is to find a brass spacer to fit where I have the extraneous o-ring. It isn't an airtight connection, just a mechanical spacer. My original 'fix' involved both an extra airtight seal and a mechanical spacer. This is so much cleaner and not in a place it can fall out and get lost. Just using the o-ring as the spacer would probably work, but that even makes me a little nervous.
This is the ScubaPro universal kit. It is the one that sealed "as is", but it is marked to show where I added the spacer.
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This is hilarious. It takes quite an imagination to compare a space ship with a scuba tank. Well, I guess they're both cylindrical....
---------- Post added November 20th, 2014 at 10:09 PM ----------
The only DIN fill whips that I've seen look exactly like the DIN fittings on regulators, which makes sense because they mate with the valve exactly like regulators. These fittings are the 300 bar length (7 thread) and fit both the 200 and 300 bar valves. So are you talking about a different kind of fill whip? I'd like to see a photo of what you are talking about if you can find one.
This link will show the difference. DIN Scuba Fittings
The first pic below is a proper 300 BAR fill whip which will only fit a 300 BAR valve as the head pin is too long for a 232 BAR valve (and yes they are a pain) which prevents using a 300BAR compressor on a 232 BAR tank. The second picture is a 300 BAR DIN regulator which will fit a 300 BAR valve or a 232 BAR valve. Clearly most dive shops use a 300 BAR whip designed to be used for regulators but allow filling of both 232 BAR tanks and 300 BAR tanks (and is sort of safe as long as you watch the tank fill 100% of the time so you do not exceed the pressure). If you buy a transfill whip (used for transferring air from one tank to another) it usually has the 300 BAR "reg" fittings thus allows supply or filling of either 300 or 232 BAR tanks.
Looking at your pictures, when you screw the reg to the valve, is it running out of thread so you cannot screw it in far enough? If its a true 300 BAR reg DIN fitting it should have heaps of thread to allow the fitting to seat in the valve with some left over. Incidentally, the reg shown was a K valve reg and I converted it (and 3 others) to 300 BAR DIN which the reg body shows it is actually rated for.
I will try and take some measurements of the DIN fitting if that helps you analyse the issue, the head pin is 2.7 mm and 10 mm diameter, the non threaded head piece is 7 mm and 20 mm diameter, thread section from thread face to inside of the section you use to screw it 18.3 mm. Sorry for the metric.
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This is hilarious. It takes quite an imagination to compare a space ship with a scuba tank. Well, I guess they're both cylindrical....
---------- Post added November 20th, 2014 at 10:09 PM ----------
The only DIN fill whips that I've seen look exactly like the DIN fittings on regulators, which makes sense because they mate with the valve exactly like regulators. These fittings are the 300 bar length (7 thread) and fit both the 200 and 300 bar valves. So are you talking about a different kind of fill whip? I'd like to see a photo of what you are talking about if you can find one.
The reason I quoted the space shuttle is the relationship between accepted practice and then deviating from it and then over time accepting that the deviation is OK in the main because of no recorded incidents in that time. There was a presentation on it by an astronaut (Mike Mullane) called "Normalised Deviation". In it he shows where NASA allowed themselves to deviate from safety standards that would normally stop a flight, on the basis that after 40 flights with one damaged O ring (of 2), nothing untoward happened. They normalised their deviation and made it accepted practice even though at the start it was considered dangerous. Then on one cold night, the inevitable happened. See the link Public Safety Education Network its well worth watching and very much applies to diving
There are threads left on the outside and room between the DIN wheel and the valve. So I don't know why the DIN wheel and threads aren't going deep enough on some of the systems. No visible reason why they shouldn't. All the DIN systems (on the regulators) measure the same (by metric ruler and eyeball) so it may be some subtle irregularities in the threads. I AM NOT going to take a tap to the valve threads to clean them up, nor is it worth my money to buy a new tank valve (assuming I can find one and that it might have the same problem), since I can use things 'as is' by shifting which regulators I use where.
I am enjoying the back and forth in this whole thought process, and even did appreciate your space shuttle reference as a normalization of deviation example. That phenomenon is a real problem in all areas of safety systems work. The level of consequences however were a little over the top.
BTW the o-ring spacer is very solid. I bang and rock the regulator every time I pass it and not a psi (millibar LOL) lost.
R
redacted
Guest
In the seaair kit, where is spacer (#35) installed?
I don't recognize the din wheel on your 2nd pic of the Scubapro din that is working. Mine are either metal or look like this: ScubaPro "300 bar" (4350 psi) DIN Conversion Kit at LeisurePro. It would not take much of a difference in lengths to cause a problem, even with 7 threads. Regardless, the small spacer between the wheel and the retainer looks like a reasonable solution.
Also, I was was comparing the 4 din regs I have (all 300 bar, 2 x Mk5s, a Mk10 and a Mk20) and a few spare din fittings (various, unknown brands) I found in the bottom of a drawer; and I think I am seeing some small differences in the length of the shoulder the din wheel presses against. They look to all be about 7mm with maybe as much as .5 mm variance. Since the wheels can be swapped around pretty easily (from various manufacturers) that may be the source of your problem.
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