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Post by sitkadiver on May 22, 2013 9:12:35 GMT -8
Bob, the Hydro Twin is also a balanced first stage. The Duel Air, with the tilt valve, will look a lot different than a Hydro Twin for the second stage lever. The tilt valve is a bent rod-shaped device for the Duel Air. John John, This is where things get confusing to me. I was under the impression that the Hydro Twin has the same as a Dual Air, but the downstream 2nd was used instead of a tilt-valve. Meaning the Hydro Twin was unbalanced, and the balanced 1st stage came along with the Hydro Twin II. My NED reg is a Hydro Twin, and the IP changes with tank pressure, so I don't think it's balanced, but I get confused when I read things about the Master Diver 1st Stage, being converted to a non-blanced reg for the DH application. Do you know what was changed inside the 1st stage of the Master Diver to make it unbalanced?
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Post by SeaRat on May 22, 2013 9:26:44 GMT -8
Dave,
I'll have to look at my Hydro Twin. But I'm pretty sure it is balanced. I'll look at Basic Scuba to see what it says about the Master Diver too.
John
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Post by SeaRat on May 22, 2013 18:45:32 GMT -8
Dave, The best way to envision the Hydro Twin is to look at this parts diagram. If you look at the HP side, and the high pressure seat, you will see that there is a new piece, numbers 47-50, which produce a balance chamber for the balanced first stage. Concerning the Master Diver, there were two models. The 1960 and 1961 models were an unbalanced diaphragm stage. The 1962 Master Diver was, according to Fred Roberts in Basic Scuba, "Single Hose; Two Stage: High Pressure Stage--Spring Biased Diaphragm, Balanced Type; Demand Stage--Upstream Tilt Valve Type" (Page 161). Fred Roberts put a note into the text, saying: I will scan the diagram in the beginning of Fred's book to show how the balancing is accomplished by Sportsways. John
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Post by SeaRat on May 23, 2013 13:00:09 GMT -8
Here is the picture I promised which shows how the Sportsways Master Diver/Hydronaut/Hydro Twin first stage achieves its balanced properties. Here is what Fred Roberts wrote on page 52 of Basic Scuba: Figure 3-2(b) is the same configuration as the Hydro Twin and Hydro Twin II. John
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Post by sitkadiver on May 23, 2013 18:53:54 GMT -8
Thanks John, That was a lot of leg work. Are you getting this from a 3rd edition of Basic Scuba? I have the 2nd edition and those figures are not there. In fact, my version states the following: (from the thread above) According to Fred Roberts in Basic Scuba 2nd ed., pp. 164, "The operation of the first stage is similar to the 1962 Master Diver except the high pressure seat(20) is not balanced." Read more: vintagescuba.proboards.com/thread/3077/sportsways-hydro-twin?page=3#page=2#ixzz2UAtUzQiPSo I just don't know. Could Basic Scuba be calling a Hydro Twin II a Hydro Twin? John, What if I hook both my NED reg and my Hydro Twin up to various tanks of various pressures.... If I do get different IP's, then will that determine if my regs are not balanced. That has always been my assumption..... I may try it tonight, if just to keep the kids busy..... I have a tank at home at 500 psi, one at 1500 psi and several full tanks..... Maybe use four: 500, 1500, 2400 and 3000?
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Post by SeaRat on May 23, 2013 21:13:40 GMT -8
Dave, I wasn't able to get the entire post posted. I had hoped to include the diagram, but that did not "take" either. I'll try again below.
Your tests should tell you what you want to know without going into the first stage and looking. I'm looking forward to hearing about your tests.
Concerning the Hydro Twin, that was not discussed. I think I have the second edition, which only includes the Duel Air. But the Master Diver was discussed, and the balancing concepts. I'll finish my post, and let you take a look a bit later tonight.
John
PS, I was able to edit the above post and put that diagram up on the board.
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Post by sitkadiver on May 29, 2013 10:09:58 GMT -8
John, Hopefully this will shed a bit of light on things. According to Fred Roberts in Basic Scuba 2nd ed., pp. 164, "The operation of the first stage is similar to the 1962 Master Diver except the high pressure seat(20) is not balanced." Read more: vintagescuba.proboards.com/thread/3077/sportsways-hydro-twin?page=3#page=2#ixzz2UhliMWQHHow, exactly, you "unbalance" a reg is beyond me. But I did the experiment we diuscussed and I think you will find this interesting. I used three tanks with respective PSI's; 450psi, 1500psi and 2800psi as a starting point. I then ran three different regs through 3 breath cycles on each tank. The regs were the Hydro Twin, a DA Aqua Master and a Royal Master(balanced). I did not use any modern regs and I used the same IP guage for each test. I did not re-test the tank pressure after each 3 breathe cycle and assumed the pressure drop would be negligible. I also tested the known balanced reg last, so I could minimize the effects of pressure differencees. Here are the tanks. Lower pressure, 450psi on the left, 1500 psi in center and 2800psi on the right: The Hydro Twin was up first. This reg surprised me. I didn't think it was balanced, and this test confirmed it is not. But what was surprising, was the change in IP between the 450 psi and 2800psi tanks. At 450 psi supply pressure, my IP was 135, at 1500psi supply pressure, the reg's IP was 110. A drop of 25 psi! At 2800 psi supply pressure, the Hydro Twin was showing an IP of 80 psi..... That's right 80 psi.... Up next, was a DA Aqua Master; An unbalanced 2 stage regulator. This reg also had a good change in IP, but not as much as the Hydro Twin. At 450psi supply pressure, the Aqua Master was showing an IP of 115psi. At 1500 psi, it was 100 psi of IP and at 2800psi supply pressure it was the same IP as the Hydro Twin, 80 psi. Lastly, I tested a Royal Master, that was original inside and did not have a captured o-ring like the RAM, but since it had a fresh rebuild, I thought I could trust it. The IP held steady at 115psi with 450 and 1500 psi of supply pressure, however, my IP jumped 5psi on the full tank!!! Was hoping for a rock solid IP, but I can live with a 5psi change on a tank that's close to 3,000psi. Here's the Royal Master on a 2800 psi tank..... This will probably be easier to read in a table format. I'll try to get on done today...
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Post by sitkadiver on May 29, 2013 10:12:09 GMT -8
TANK PRESSURE HYDRO TWIN I.P. AQUA MASTER I.P. ROYAL MASTER I.P. 450 psi 135 psi 115 psi 115 psi 1500 psi 110 psi 100 psi 115 psi 2800 psi 80 psi 80 psi 120 psi
Sorry folks, don't know why I'm having trouble cutting and pasting from Excel.....
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Post by Linda on May 29, 2013 12:53:47 GMT -8
You can format a table in the reply window, but it still took forever to transfer the info into the table. If there's better way, I couldn't find it... TANK PRESSURE | HYDRO TWIN I.P. | AQUA MASTER I.P. | ROYAL MASTER I.P. | 450 psi | 135 psi | 115 psi | 115 psi | 1500 psi | 110 psi | 100 psi | 115 psi | 2800 psi | 80 psi | 80 psi | 120 psi |
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Post by sitkadiver on May 29, 2013 13:32:41 GMT -8
Thank You Linda. I tried the table button, but then couldn't see an easy way to add the information. Sorry to bug you with this.
Table looks perfect BTW - Thank You.
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Post by Linda on May 29, 2013 18:07:02 GMT -8
No bother, I was hoping to find an easy way for you to do this, but I had the same rotten luck.
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Post by SeaRat on May 30, 2013 7:48:14 GMT -8
Dave, that's really interesting. Now, I'm going to have to try that on mine. I was going to wait until I dove it, and I did pull apart two of my Sportsways single stage regs to show the difference in the balanced and unbalanced designs. Here are the two different designs for the Sportsways Sport Diver regulators, one balanced and one not balanced: Below are details of the first stages: Now, from the parts diagram I have of the Hydro Twin, it has the balanced first stage. But I need to look at mine to see. I'll do that, then propose a reason for Dave's to be unbalanced. If you'll notice the balanced design, you cannot see the stem of the seat, but it is hollow, with a hole running all the way through the seat longitudinally. This pressurizes the top portion, and should make for a balanced design. But if that hole is blocked by corrosion, it could probably become unbalanced. Later today I'll take my Hydro Twin first stage apart to see the innerds and confirm whether it is balanced or not. John
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Post by CG-45.com on May 30, 2013 8:14:47 GMT -8
Thanks for sharing all pics and informations...I'm learning a lot here!!!
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Post by nikeajax on May 30, 2013 11:11:51 GMT -8
I'm a wee-bit-confused; so the Navy-Unit is unbalanced? DAVE... you gave me an unbalance reg?!?!?! SNORT!!!! Gosh, I was under the impression it was balanced--so now I know! One-a these days I gotta get me a coupl'a second stages fer that thing... Jaybird
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Post by SeaRat on May 30, 2013 11:14:11 GMT -8
Dave, I was hoping to test the intermediate pressures of my Hydro Twin, but my gauge is missing (we are doing some remodeling, so my space is a mess). So I popped off the end cap of my first stage. My Hydro Twin is definitely a balanced first stage; the mechanism is there. I'll try to get some photos later today. It is as depicted in the drawings above, but not the same as the Sport Diver balancing mechanism. The balance chamber has a hole in the threads of the body itself that puts the pressure into the other side of the shaft.
I do have a feeling that either your regulator has some corrosion blocking this hole, or the mechanism is entirely different. This has become quite interesting.
John
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