200 psi IP

[ofg-1]

OK you regulator guys

I need to modify a Conshelf 14 first stage to try to get about 200psi of IP, maybe a bit more. Why, you ask? I want to be able to service the landing gear struts on my airplane without paying a A&P $100 an hour.

I am thinking of putting another main spring inside of the original spring. I know I will need a custom hose. I have a overpressure valve, but am not sure if it will go that high.

Thoughts?

 

[GF99/99]

I am not very familiar with the Conshelf but if I am not mistaken this reg does have an adjustable IP. Have you not just tried cranking down on the IP adjustment screw. I would think you should be able to get up to 200psi.

 

[grantctobin]

XS Scuba/Highland Adjustable OPV cranked tight
Stronger spring

If you send dimensions to Martin at Tecme he might be able to make one. You’ll need a stronger spring. Worst case, Fathom has parts readily available to allow this on an ApeksDS4. Piranha has some LP hoses w higher working pressure.

 

[ofg-1]

I can't get the existing adjustment up to more than about 170 psi. I could also cut a few threads off the adjustment screw to allow it to go in further, but I am not sure if thats a good idea.

I will look at the adjustable OPV.

 

[Couv]

@Luis H ,was telling me and a few others just last night that a spring within a spring might be a workable idea. As @marsh9077 suggested, have you first attempted to crank down on the IP adjustment screw? (Edit: I see you answered that question as I was typing.) If you cannot then get the IP where you want it you can try shimming the spring. If still no joy then try the addition of another spring.

Now, as an A&P I hope you are using Nitrogen* in your landing gear struts. If so, why doesn't the nitrogen bottle have a regulator that you can CONTROL the exact amount of pressure going into the strut?

*I concede scuba tank air should be dry enough and can serve as a reasonable alternative, but if this is something you are going to equip yourself to do rather than modifying a scuba regulator to service your struts, why not modify an adjustable regulator to fit your scuba tank instead?
McMaster-Carr

 

[GF99/99]

I can't get the existing adjustment up to more than about 170 psi. I could also cut a few threads off the adjustment screw to allow it to go in further, but I am not sure if thats a good idea.

I will look at the adjustable OPV.

Have you tried stacking some small washers under the spring to take up more space?

for OPV check Grainger or McMaster they should have lots with all different ranges

 

[kelemvor]

Now, as an A&P I hope you are using Nitrogen* in your landing gear struts. If so, why doesn't the nitrogen bottle have a regulator that you can CONTROL the exact amount of pressure going into the strut?

Exactly what I was thinking. You can get a nitrogen reg on amazon for $65 (less if you search) https://www.amazon.com/Uniweld-RHP400-Nitrogen-Regulator-Connection/dp/B008HQ6GXO then go to airgas or whoever your local supplier is and buy yourself a bottle of nitrogen.

 

[axxel57]

I had a discussion in another forum about rising IP possibly opening the valve of an SP inflator.
I took a Conshelf and screwed the adjustment screw to about 350psi, the valve wouldn't open.
So adjustment to 200psi IP is technically also without modification no problem at all......

 

[GF99/99]

I had a discussion in another forum about rising IP possibly opening the valve of an SP inflator.
I took a Conshelf and screwed the adjustment screw to about 350psi, the valve wouldn't open.
So adjustment to 200psi IP is technically also without modification no problem at all......

I know in the previous post it was stated that he can only get it up to 170psi but I am surprised too that he can not just crank down on the screw and get it up to 200psi. I know on my Apeks regs this is very easily achievable. I actually run the ds4 on my Triton at 11.5 bar (about 170psi) as per the manufactures spec. And the dil side US4 on my JJ I run at 10 bar about (150psi) and there is still plenty of of turns left on the adjustment cap and a little 1/8th or even 1/16th of a turn really makes a big change on the IP. I can image if I did a full revolution I'm sure I could get it way up there!

 

[rjack321]

I know in the previous post it was stated that he can only get it up to 170psi but I am surprised too that he can not just crank down on the screw and get it up to 200psi. I know on my Apeks regs this is very easily achievable. I actually run the ds4 on my Triton at 11.5 bar (about 170psi) as per the manufactures spec. And the dil side US4 on my JJ I run at 10 bar about (150psi) and there is still plenty of of turns left on the adjustment cap and a little 1/8th or even 1/16th of a turn really makes a big change on the IP. I can image if I did a full revolution I'm sure I could get it way up there!

My DS4 got unstable around 170psi. It required a stronger spring to get to 200psi. I'm not surprised the OP can't get over 170ish on his. Stronger spring or shims/washers should help though