[PSUBS-MAILIST] air compensation

Thu Aug 3 13:07:16 EDT 2023

Hi David
Been following the thread and the first stage regulator will freeze up from the outside moisture.  We use environmental kits on our first stages , the rubber boot/bladder, that are filled with vodka 😂. (Gray Goose). This keeps the external parts from contact with water.  The air I have here is very dry as I have special filters . Last test was -61F.
The first stage regs are not intended to have continuous hi rate flows because of the expansion cooling .
[image0.jpeg][image1.jpeg][image2.jpeg]
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On Aug 3, 2023, at 11:46 AM, Bernie Hellstrom via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

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On Aug 2, 2023, at 10:40 PM, Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Let us know what you find.

Best

On Wednesday, August 2, 2023 at 09:24:18 PM CDT, David Colombo via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Cliff, something I experienced at Charlevoix, was the first stage regulator in the VAST was going into a freeze cycle when dumping air into the ballast tanks when we were getting the ballast corrected with multiple short dive attempts and then back to the surface. It now has me wondering whether the air we got from Bernie moist, or the formation of ice crystals on the outside of the regulator was from the air coming from the hp vs lp port. I need to look at the regulator tonight to think this thru.

Best Regards,
David Colombo
[http://static.squarespace.com/static/533310a9e4b0fba62008a464/t/5339c1f2e4b041bac4e25d1b/1396294132055/?format=500w]
804 College Ave
Santa Rosa, CA. 95404
(707) 536-1424
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On Wed, Aug 2, 2023 at 4:36 PM Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org<mailto:personal_submersibles at psubs.org>> wrote:

Alec, I setup a spreadsheet to analyze the following setup.

 A scuba tank has a 1st stage regulator attached.  A Tescom 44-4069 pressure reducing regulator with venting is attached and tubing is connected from the HP port to a set of Minn-Kota 101 motors.  The question is can the small orifice in the HP port pass sufficient air to handle the demand for air in thrusters to keep the pressure a fixed differential pressure above ambient water pressure.

The calculation indicates this arrangement will work.  If anyone wants a copy of the spreadsheet, please email me your email address and I will send.

The calculation indicates the HP port could be used for this.  Having said that, yes, this a simple clean setup but so is connecting to a spare LP port.  The advantage of the LP port is that pressure rating of the regulator body can be less so less 316 stainless and less cost.  Would be good to spec a regulator like the Tescom 44-4069 regulator with its venting capacity but for pressures one would expect from the LP port.

Cliff

PS: Hope you got your Land Rover back from the shop.

On Tuesday, August 1, 2023 at 04:09:41 PM CDT, Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org<mailto:personal_submersibles at psubs.org>> wrote:

Hi Cliff,

"The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input port of Tescom 44-4069 regulator."

There's a little problem with this plan, though easy to work around. The HP ports on regulators have a tiny orifice, in order to prevent rapid loss of air if a hose or SPG fails. These ports cannot provide the sort of flow you would want.

Best,
Alec

On Tue, Aug 1, 2023 at 12:17 PM Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org<mailto:personal_submersibles at psubs.org>> wrote:
Sean, the specs do look good on this unit.  To me the issue is going to be the cost.  As background, the Parker regulator that Hugh, Alec and I have used for this application is the 364-02BSS/M1 Parker Watts Pneumatic Regulator.

https://store.livhaven.com/r364-02bss-m1-watts-fluidair-pneumatic-regulator at $217.51.  I purchased mine off ebay for a fraction of this.

When I had the Parker 364-02BSS/M1 installed for pressure compensating for my four MK 101s, it was connected to the LP port from my AquaLung Titan balanced diaphragm first stage regulator. I had the Parker 364-02BSS/M1 adjusted to give about 2 psi over ambient.  I had the first stage set to 50 psi over ambient water pressure.  I use this for BIBBS and blowing the MBTs.

The Tescom 44-4069 regulator would run directly off the HP air tank pressure then output go directly to thrusters.  It would be interesting to compare the Cv's for both regulators to get a feel on how much air flow rate they can provide to the thrusters descending and venting when ascending.

The Tescom 44-4069 regulator would be a clean installation with just a single 1/4 SS tubing run from the HP port of the 1st stage regulator to the input port of Tescom 44-4069 regulator.  From the output port of the Tescom 44-4069 a single 1/4 SS tubing to a Swagelok Tee that branched off to two more "T"s to give four 1/4 SS tubing runs to the thrusters.

We need to get a RFQ on one of these regulators.  Do you have a preferred supplier?

Cliff

On Monday, July 31, 2023 at 09:47:29 PM CDT, Sean T. Stevenson via Personal_Submersibles <personal_submersibles at psubs.org<mailto:personal_submersibles at psubs.org>> wrote:

I would be inclined to use a Tescom 44-4069 regulator for this purpose. Not sure what these sell for.

Sean

-------- Original Message --------
On Jul. 31, 2023, 20:37, Cliff Redus via Personal_Submersibles < personal_submersibles at psubs.org<mailto:personal_submersibles at psubs.org>> wrote:

My original air competition for the R300 used the regulator that Hugh Fulton has on QSub.  These are pricey new but you can get them used on eBay.  I was operating all four of my Minn kotas 101 off this single regulator.  It was a special ss pressure reducing/pressure releasing regulator.  I had it installed on my last Florida dive which I went down about 100 ft .  Unit worked fine.  My first failure was on Flathead lake expedition in which one of my aft thrusters flooded.  After that I switched to oil compensation.  Alec is using same regular on his articulated arm and not the thrusters. He felt issue with the regulator was that the port for releasing pressure on ascent was too small.  I believe he has addressed this by adding a pressure release valve or OP valve.  He can elaborate more on his current strategy.

Cliff

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On Jul 31, 2023, at 9:14 PM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org<mailto:personal_submersibles at psubs.org>> wrote:

John,
I am happy with both air & oil.
Am intending to fill my thrusters with oil, but have the oil pressurized off my air comp system. This will reduce air use to just whats in the lines.
My electric manipulator will be air compensated off the same unit. Putting oil in it adds another layer of complexity.
I think I need to put out a long video once I've finished this
air compensator.
From what I am hearing from Cliff, he didn't get enough air delivery from the single regulator he was using. However I thought this was the same unit that Alec is using & was now happy with.
Alan

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On Tue, 1 Aug 2023 at 1:29 pm, Jon Wallace via Personal_Submersibles
<personal_submersibles at psubs.org<mailto:personal_submersibles at psubs.org>> wrote:
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