scubapeter
Lung Diver
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Joined: Fri Oct 01, 2010 12:31 pm
First Name: peter
Location: Macedon NY

HPR second stage for hookah diving!?!?

Mon Sep 19, 2022 5:37 pm

I have used surface supplied (hookah) gear, in one form or another for many years. Until recently, I had never attempted to use an aquamaster via the hookah port. I did some informal (and highly subjective) tests using a industrial breathing air regulator for my supplied air. I opted to use an unbalanced aquamaster since utilizing the hookah port provides the intermediate pressure. The advantage of the large industrial regulator is that the IP can be fine tuned over a very broad range of pressures. I tried two regulators, one with a standard second stage and another with an HPR second.

I found that the HPR provided much better breathing characteristics across the board. This difference was quite apparent at lower pressures. I found that the HPR equipped regulator breathed acceptably well below 70 psi. Again, these were just my observations and by no means a conclusive test.

Btw, Simon beans still makes the excellent hookah harness!

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luis
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First Name: Luis
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Re: HPR second stage for hookah diving!?!?

Tue Sep 20, 2022 1:00 am

I am glad you like it. :)

There is a reason why I called the second stage HPR (High Performance Regulator). 8)


With the HPR you have the ability of making three independent adjustments: the lever height, the spring tension (which can control cracking effort), and the amount of venturi assistance.

I am just about to write some more details on how to adjust all three, but here is a little advance information. I have shared most of it in other posts, but I will add more.
Note: I just designed a new flow diverter for my DSV design, that allows me to take full advantage of the maximum venturi flow.

1) The lever height adjustment is kind of intuitive. You use the nut on the seat carrier to adjust it.

2) The spring tension can be reduced by backing (unscrewing) the HPR body in increments of half turns (180 degrees). Cracking effort is fine-tuned by balancing the spring pressure against the IP.

3) The venturi flow can be adjusted, by changing the ratio, of the amount of air in the jet pointing down the horn, to the amount of bleed air going into the can. The adjustment is done by blocking the side bleed air ports to the desired amount. I will expand on this.


From the early design stages I tried to make the HPR a very adjustable second stage with ability to push the performance...
Luis

Buceador con escafandra autónoma clásica.

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simonbeans
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First Name: Allan
Location: Rochester NY

Re: HPR second stage for hookah diving!?!?

Tue Sep 20, 2022 9:03 am

Pete,
I humbly thank you. It took a while to figure out the design of the hookah harness. And I am sorry that I don't recall who provided me with a drawing or photo of the original harness that USD used in the 1950s or 1960s. It was a simple and very efficient design that makes it so nice.
Allan

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Check out my website: www.vintagescubastuff.com

scubapeter
Lung Diver
Posts: 60
Joined: Fri Oct 01, 2010 12:31 pm
First Name: peter
Location: Macedon NY

Re: HPR second stage for hookah diving!?!?

Fri Sep 23, 2022 11:41 pm

Luis, what would be an ideal incoming intermediate pressure for the HPR?

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luis
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First Name: Luis
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Re: HPR second stage for hookah diving!?!?

Sat Sep 24, 2022 4:10 pm

When I am using the HPR on an Argonaut/ Kraken or with a Phoenix first stage (or for that mater a RAM or similar) I tent to adjust the IP (intermediate pressure) between 120 PSI to 130 PSI.

The maximum IP (or 130 PSI) is mostly driven by the heavy spring in those first stages. If you adjust the IP above 130 psi the 1st stage spring becomes almost totally compressed and it behaves erratically (it is not in its linear compression range).

I like to keep the lower limit to at least 120 PSI since it provides good performance. But the HPR seems to perform well even at lower IP. With the mechanical advantage of the large diaphragm and the HPR lever, the HPR has a low cracking effort over a large range of IP.

One of the features of the HPR is that you can adjust the spring tension to accommodate a very large IP range. If needed (very unlikely), the spring tension can be increased by adding a plastic washer under the spring.

To reduce the spring tension in the HPR (to accommodate very low IP) is a lot easier. Just unscrew the HPR by 180 degrees (half a turn) at a time until the desired spring tension/ IP combination is reached.

When unscrewing the HPR, remember to always lift the lever (turn it up vertically), to lift the seat carrier, so that the seat is not cut or damaged. If you forget to lift the seat, the volcano orifice can cut the seat when turning it.

When using the HPR in an Aqua Master (or RAM), in a hookah rig, you will have a very large IP air volume in the long hose. This will act as a gas accumulator which will tend help keep a constant IP. The constant IP helps with performance.
Luis

Buceador con escafandra autónoma clásica.

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