Scubapro chrome plated brass regulators...

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Never mind the tank pressure. Adjust the cracking effort of the second stage at the highest IP of the first stage.
Yes but what I’m finding lets say I adjust the cracking effort to 1 with a tank @ 1000 psi and then install a tank @ 3000 psi and recheck the Ip it will be at .7. Static Ip lockup is fairly consistent @ varying tank pressures but IP recovery after the valve opens is lower (with low tank pressure) and this changes the measured effort in this case .7.

what am I missing? Pulling my hair out... oh wait I have no hair. Lol
 
The next item to plumb into the system will be a vacuum accumulator-probably a wine bottle with a t-fitting in the stopper
I think you need a SUPER accumulator. Say, nine wine bottles in parallel.

Oh, look! I just happen to have that many empties lying around my lockdown lair! I'll send 'em to ya, @couv . I'm just that kind of friend.
 
I think you need a SUPER accumulator. Say, nine wine bottles in parallel.

Oh, look! I just happen to have that many empties lying around my lockdown lair! I'll send 'em to ya, @couv . I'm just that kind of friend.
You guys are fancy, I buy wine by the box.
 
Well you could configure the wine bag inside the box for the accumulator bladder. :)
In the presence of vacuum the bags volume may prove insufficient
 
Yes but what I’m finding lets say I adjust the cracking effort to 1 with a tank @ 1000 psi and then install a tank @ 3000 psi and recheck the Ip it will be at .7. Static Ip lockup is fairly consistent @ varying tank pressures but IP recovery after the valve opens is lower (with low tank pressure) and this changes the measured effort in this case .7.

what am I missing? Pulling my hair out... oh wait I have no hair. Lol

I’m guessing this is no longer a static cracking effort test now were measure dynamic flow effort on a small scale. My set up is a duplicate of my airflow analyzer on a small scale.

So is it best to make the effort adjustment after first ip recovery or first in dip (like the traditional static test). I get a consistent reading after the first ip recovery at even with varying tank pressures. If on the second dip where the ip will eventually settle based on tank pressure effort will change by a few points. I believe in the book static cracking effort is taken as soon as you see the needle move.
 
Yes but what I’m finding lets say I adjust the cracking effort to 1 with a tank @ 1000 psi and then install a tank @ 3000 psi and recheck the Ip it will be at .7. Static Ip lockup is fairly consistent @ varying tank pressures but IP recovery after the valve opens is lower (with low tank pressure) and this changes the measured effort in this case .7. what am I missing? Pulling my hair out... oh wait I have no hair. Lol

Let's review:
The Intermediate Pressure (IP) is the pressure available at the second stage. (It also closes the first stage valve-but that is not relevant here.)

The second stage does not care about the tank pressure-only that it receives usable and steady IP. Some first stages have greater IP at lower tank pressure-some have greater IP at higher tank pressure. If I'm going to sell a second stage separate from a first stage, I tune it to an IP of 135 psi as that splits the usual tolerances. If I'm selling a second stage with a first stage, I adjust the cracking effort when the IP from the first stage is at it's greatest pressure.

Cracking Effort is altogether different. Cracking effort is the amount of pressure differential it takes to open the second stage demand valve. This pressure differential is usually measured in inches of water. Put simply, it is the amount of vacuum inside the second stage case applied when the demand valve opens. We only observe the IP drop as an indication of when both the first stage and second stage demand valves open.
 
Let's review:
The Intermediate Pressure (IP) is the pressure available at the second stage. (It also closes the first stage valve-but that is not relevant here.)

The second stage does not care about the tank pressure-only that it receives usable and steady IP. Some first stages have greater IP at lower tank pressure-some have higher IP at higher tank pressure. If I'm going to sell a second stage separate from a first stage, I tune it to an IP of 135 psi as that splits the usual tolerances. If I'm selling a second stage with a first stage, I adjust the cracking effort when the IP from the first stage is at it's greatest pressure.
Yep I get all that... but it’s different now that we are Continuously flowing the second stage isn’t it?. First stage locked up valve closed IP 135. Second stage sees the 135 with its valve closed. It’s been adjusted so the 135 and spring tension balance to keep the valve closed. Now we turn up the flow to create the vacuum needed to open up the second stage valve. Now the second stage is flowing. First stage valve opens and IP is no longer 135, unless you measure effort as soon as it cracks open your measuring for the most part the effort at 135. Now it’s trying to maintain +or- 10 psi in my case tank pressure makes a different where the IP ends up while it’s flowing. And the small downward change in IP means I need more effort to keep the valve opened at the same micro flow rate (5CFH) right? My 1st stage regulators when flowing at reduced tank pressure won’t regulate @ the original IP when the valve was closed. or just cracked, and this I find effects inhalation effort on the meter anyway, I see this in reg Savvy book page 175 at different flow rates the effort increases when the venture is set to min, and sense were flowing so little there is no venturing I’m guessing. So I’m sure at higher flow rates the effort goes up because it takes increased effort to compress the spring to further open the valve , but I’m thinking the small changes in IP also effects effort and with this small micro pump we’re seeing this where we weren’t able to see before with traditional cracking effort tests. I included a few picture above two different seconds same first stage at different tank pressures. Just playing and learning from you guys while cooped up in the house.

Maybe my explanation isn't very good or I’m not good at explaining what I’m thinking. but I’m trying. Lol

Thanks for all your help. And everyone’s input on this thread.
 
https://www.shearwater.com/products/perdix-ai/

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