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Post by Michel on Jun 6, 2004 17:47:46 GMT -8
I'm just finishing building a test pressure gauge for
calibrating the LP 2nd stage on the DAs like the original
USD tool #1116-00 and #1125-00. I'm using top of the line s.s. Swagelok gauge, t fitting and bleed screw, a U.S. high end precision fittings company. However, I'm
stumped on the adaptor end which screws into the LP
port, it does not seem to be standard and has a very shallow(flat) thread, almost a common pipe thread? Is the adaptor still available or does anybody know the exact adaptor size and thread if they have one or have had one machined? Thanks for any help, Michel A.
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Post by BLT on Jun 6, 2004 18:38:44 GMT -8
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Post by Captain on Jun 7, 2004 10:47:02 GMT -8
The thread size for the LP nozzle on the DA Navy is 9/16 X 18. Some 3/8 tubing compression fittings use this size. You could take the body to a hardware store and try to find one that fits. Also one could be made from a 9/16 x 18 NF bolt by cutting the head off of the bolt, drill a 1/8" hole through it and threading the the other end 1/4 X 18 pipe thread.
I think the easiest way is to find a 3/8 tubing to 1/4 pipe compression adapter with the 9/16 X 18 thread on the tubing end. You will need to use some type of gasket to get a seal.
This is for the DA Navy that uses the horseshoe with the LP seat on it not the DA AquaMaster. The easy way with the AquaMaster is to took up to the hooka port with a B oxygen hose fitting found at a welding supply store
Captain
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Post by Michel on Jun 7, 2004 13:03:06 GMT -8
Thanks guys, but you know if you use the hookah port
you still have the lp port semi-exposed even when the
seat assembly is in and closed not allowing you to pro-perly calibrate the pressure at that port within specs.
It has to be done by the book and somebody must know the measurements for the adaptor. I may have to
get pushy with AquaLung again, like a New York client I
once had , the sqeaky wheel gets the oil! and I'm not
going away, even if I have to hire an engineering firm!
Michel A. (psychotic).
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Post by Bryan on Jun 7, 2004 13:21:48 GMT -8
So are you saying that if I attach a gauge to the hookah port and adjust the LP pressure to spec and then I put my gauge directly on the LP port itself that there will be a difference in pressure ?
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Post by Captain on Jun 7, 2004 13:50:06 GMT -8
I don't think so. Navy non-magnetic DA's had no hooka port so they had to use the adapter. Or you put it on a tank with 500 psi and crank up the IP until it starts to free flow and than back it off until it stops. Done deal.
Bryan, I see you survived Florida or is it vice versa.
Tom
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Post by Bryan on Jun 7, 2004 14:28:10 GMT -8
You are 100% right as usual Tom!
I survived Florida and I'm warming up for our adventure at Toledo Bend!! I think I'll have the Spiro operational by then.
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Post by Michel on Jun 7, 2004 18:30:00 GMT -8
Some of you are missing the point. Yes you can adjust
the LP port pressure using hookah port but only assuming you have a properly seated 2nd stage seat
assembly. If you are rebuilding the reg or replacing the
2nd stage seat and/or cleaning it you must follow proper test procedure not test thru hookah which must
also be checked for leakage after.No USD repair manual
from the late fifties to the seventies suggests the hookah port as a short cut, not even the last '70's Royal
DA rated at 3500psi! I think the factory had good reason for this, maybe Dan Barringer could settle this
point for us, Dan I'd really like to know? Michel A.
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Post by Captain on Jun 7, 2004 19:45:04 GMT -8
I understand your concern however you need to correct any leaks in the second stage seat before the final setting of the IP. With the gauge on the hooka connection you can apply finger pressure on the second stage seat, if the IP rises when you do this the second stage seat is leaking. Generally with a good second stage seat it takes an IP of around 150 pounds before it will start to freeflow. Once the seat is leak free and the IP where you want it then ajust horseshoe height with pressure on the regulator. If the horseshoe is too high it will start leaking when the diaphragm is put on. All I can say is that there is probably over 100 years of collective experience between the people on this board with the Aqua Master. I myself have been working on Aqua Masters for over 30 years. You can do it any way you want but what is being said works. Sugested reading. vintagescuba.proboards2.com/index.cgi?board=general&action=display&n=1&thread=182Tom |
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Post by Michel on Jun 9, 2004 7:08:20 GMT -8
Thanks Tom, you know I never looked at it that way!
I think your procedure may actually be more versatile
in fine tunning my DAs. But why would the factory never
suggest it, maybe they just did not want non-tech types
to fiddle with the regs in the field!? I really appreciate
your explainations and come to think of it finding the proper connector to the hookah is much easier than getting the darn USD adaptor for every diff. model DA.
What does Dan think of all this or is he keeping all his
secrets? Thanks again Tom for the heads up, Michel A.
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Post by Bryan on Jun 9, 2004 8:04:08 GMT -8
A possible reason that U.S. Divers continued to attach the pressure gauge to the 2nd stage seat orifice is due to the fact that it was that way on the original Aqua-Lung and the DA Navy series of regulator. It was the ONLY place you could attach a gauge to adjust the IP pressure. They could use the same gauge assembly and simply put a different end on it for the DA Aqua-Master series of regulators. Plus the people servicing the regulators were already used to doing it this way. This is just a guess on my part…..
I'm not going to speak for Dan but I'll give you my 2 cents on this . In the past 6 months I have serviced 19 DA Aqua-Master series of regulator.. Every one of them I have set the IP pressure by attaching a gauge to the hookah port. I have yet to have any returned to me or a complaint of leaking through the 2nd stage.
The only regulator in the Aqua-Master series that you must attache the gauge to the 2nd stage seat orifice to set the IP pressure on are the Non Magnetic regulators as they have no hookah port on them.
Another plus to having a gauge attached to the hookah port while you operate and adjust the 2nd stage lever and seat is that you can see how quickly your IP pressure rebounds after you depress and release the lever. I think you will find that you have to make many adjustments to get it just right.
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Post by Michel on Jun 9, 2004 12:34:15 GMT -8
No question Brian, I think your way is the most versatile.
It only makes sense and saves you the trouble of re-attaching the test tool to the 2nd stage port assembly to fine tune the horseshoe operation. I guess I just put to much faith in the 'oracle' (US Divers Co.) I also appreciate Brian's test work , what is the best calibration psi for deep work? is it from a 500psi tank or
2250psi, from Brian's work it would seem almost that it's personal preferance which system you choose? Thanks again everyone, I really think these adjustments are important. Michel A.
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Post by admin on Jun 9, 2004 17:24:05 GMT -8
I agree with Tom and Bryan- the hookah port on the DA's and Royals is the fastest and easiest way to check the IP pressure. Yes, you definitely have to have good LP and HP seats before you check it but the pressure from the hookah port is always identical to the pressure from the LP seat holder port/nozzle.
If you're doing a first generation AquaLung, then you need the nozzle gauge or do as Tom suggests and adjust the IP pressure until it leaks at 500 psi tank pressure, then back it off. It seems to me that the higher the IP pressure- the better breathing the reg. The only concern is that it doesn't freeflow at the low tank pressures.
Dan
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