Regulator modifications (pressure range)

[Breakdown]

Does pressure range scale direction with spring rate? I.e. if I want to double what pressure range a regulator works at, does the spring rate need to double? Or is it a non-linear relationship?

[latches109]

Which regulator? there are a lot of variables. is it moving base? Schrader valve style? but generally spring force is related to the displacement of the moving base. F=k*x + friction - where x is displacement and k is the spring constant - for a simplified version. Springs don't behave perfectly linear, especially at large deflections

[Breakdown]

Exactly

F=k*x amd F=psi*piston area... so psi*piston area=k*x. piston size and displacement are fixed. So it seems like that would reduce to psi=k from a ratio

Its an Ion reg that I want to bump from 200. i measured the factory spring and came up with something in the 220lb/in range. I found a similar size spring in the 560in/lb range

[flyweightnate]

In theory, not a bad approach. Might need to go for a harder elastomer, too, though. Piston o-rings might extrude, and seats might get "punched". A90 might be a good durometer to switch to for the typical A70 o-rings if you notice issues.

Century Spring and a few others also let you measure a spring (diameter, wire size, pitch) to calculate spring rate, which might be a little more accurate; then you can select one with a higher rate. Interestingly, almost all steel spring materials have very similar rates, even though some last much longer, so physical measurements can be very handy ways to spec a spring.

Can't hurt too bad to try. If it were Belleville stacks, it would be a much more complicated proposition.

[latches109]

Credit: zdspb.com
ion regulator

[Breakdown]

Yup! I've looked at that website more than once! I had not considered uppting the durometer on sealing o-rings though

[tyronejk]

I don't think the reg seat should not see any different forces at different pressures. I agree higher durometer orings may be needed to avoid extrusion. I would take some measurements and find some reference info online on that though. I think it's possible you'll be ok with the stock orings.

Friction should not matter and doubling the spring rate to double the output pressure should work, though I'd double check the minimum compressed length of your new spring to make sure it has enough travel for the reg seat to actually seal when the spring is compressed.

[latches109]

Exactly

F=k*x amd F=psi*piston area... so psi*piston area=k*x. piston size and displacement are fixed. So it seems like that would reduce to psi=k from a ratio

Its an Ion reg that I want to bump from 200. i measured the factory spring and came up with something in the 220lb/in range. I found a similar size spring in the 560in/lb range

Those equations would only simplify like that if displacement was fixed, but ignores the change in displacement to function as a regulator.

Shim it. Add a washer to the spring to increase preload, that should get you over 200psi. I doubt you need to buy a new spring.

[markdem]

Yes. Twice the spring pressure = twice the air pressure