Belleville washers orientation and adjustment screw

[Wokdaf]

All,

I’m trying it understand Belleville washers in general. For instance, are they and the way they are positioned, the component that is most directly involved in the psi you set in a regulator. How does their positioning increase or decrease the ability to set the psi you want and how does that work.

For example, if you set the washers like this

)()()()()()( what is the expected outcome on a 4500 psi tank?

Or if you have ))(())(())(())(( or )))((()))((()))?

Does it allow for you to set the psi higher because it’s stronger and won’t collapse from the air in the plenum pushing it back to close the air between the regulator and tank?

I’m still not sure, if just single discs does this mean u can’t set the psi too high because it’ll flatten at lower psi and thus close the regulator air pathway? Is this setup then good for if u want a low psi setup for each shot. And the screw adjustment, how does that impact the Belleville washers? Lastly, if you don’t use enough or too many Belleville washers, what happens? Thanks I know that’s a lot, I just want to understand.

 

[nervoustrig]

A parallel aka nested pair (( has the travel of a single but twice the stiffness.

A series pair () has the travel of two but the stiffness of one.

These concepts can be used in combination to achieve whatever blend of stiffness and travel is needed. So how do you apply this knowledge? Well in the simplest terms, stiffness correlates to the maximum achievable pressure...akin to what you noted about making sure the stack doesn't squeeze completely flat. If that happens, the regulator ceases to function and it simply passes input pressure to the output.

And travel correlates to repeatability / consistency. How is that? Well, consider that each of the following arrangements will support the same maximum pressure before they squeeze flat:
)
()()()()()
But the second one has 10x the available travel which is beneficial in two respects. The first is that each time the regulator cycles, the piston will lift off the valve seat by a generous amount to permit air to flow in and replenish the plenum. The second is that it is far less susceptible to a number of variables that would conspire to produce an inconsistent pressure each time the regulator cycles. Meaning things like thermal expansion/contraction of the materials making up the various parts of the regulator, mechanical tolerances / fit, and compression set and wear of the seat material over time.

Regarding how to determine what Belleville ratings you would need for a particular pressure, it is a pretty straightforward calculation involving the force operating against the small end of the piston versus the force operating against the large end of the piston. If you're interested, I went into this subject in detail in a prior discussion and shared a little spreadsheet you can use to run the numbers.

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www.airgunnation.com

 

[Wokdaf]

A parallel aka nested pair (( has the travel of a single but twice the stiffness.

A series pair () has the travel of two but the stiffness of one.

Thank you for the explanation. So that leads me to my problem of sorts. So what I noticed about the aea standard regulator?? It just doesn't seem to work. NO matter what you set the screw to, air just passes through. THAT's why I'm trying to understand the washers. I've made a crude drawing of the regulator. IF it gets crushed flat and the Probe part is long enough, it presses onto that hard plastic part on the "Screw". If that happens then the regulator WOULD be working right? However, if they're all flattened and the probe doesn't have enough travel to get "plugged up" then air just passes through, correct? So my question is, at 4500psi the washers SHOULD flatten right? they come set up like this )))(())(())(())((. Could it be that even though they are flatten, the prob doesn't get far enough to get plugged in? Or are they too rigid and can't plug it in? Because if it DOES plug in, the regulator SHOULD then be working?? Correct? AT this point I"m still a bit lost on how air moves from tank to plenum. The screw that screws into the regulator portion is the only way i see air moving in. Any explanation as to why the regulator isn't working would be greatly appreciated.

 

[Wokdaf]

Anothet question? So if I wanted to set this for say 14-1500 psi, I would want just single discs right? )()()()()()()(? If I want to be able to set higher pressure, double or even triple?? ))(())(()(())(( or heck )))((()))((()))(((?

 

[nervoustrig]

Your thinking is on the right track. If it is operating in bypass (output pressure = input pressure), the cause may be one of the following:

1. The stack is squeezing flat before the piston can reach the valve seat.
2. The piston is reaching the valve seat but the valve seat is damaged (e.g. badly worn) and therefore will not seal to halt the flow of air.
3. The O-ring on the adjuster is bad, allowing air to bypass the valve seat.

Number 3 is pretty common so I would say look there first. But also inspect the condition of the plastic seal of the valve seat. If it is badly indented, the regulator likely will not work well after you’ve replaced the adjuster O-ring. Note that if indeed the adjuster O-ring was the culprit, the seat is likely to have experienced a brutal squeeze resulting from the overpressure condition, in which case it will need to be either replaced or wet sanded flat and smooth.

 

[nervoustrig]

So if I wanted to set this for say 14-1500 psi, I would want just single discs right? )()()()()()()(? If I want to be able to set higher pressure, double or even triple?? ))(())(()(())(( or heck )))((()))((()))(((?

As mentioned previously, you can calculate it from the diameter at each end of the piston. To get some idea of what your Bellevilles are rated, you can measure one with calipers and see if you can match it up to one on McMaster-Carr.

 

[Wokdaf]

Thank you sir! Yes there’s quite a big indention in the valve seat, now granted it’s by design? These are 2 new regs I just bought and both aren’t regulating. With all this in mind, I do have to take into account t that although () might not withstand as much as this, a series of ()()() is the same as (()) to a certain degree? Meaning it’s like 30 twigs are similar in strength to 1 solid twig that has same diameter, possibly correct? Although it may be more, the 30 twigs that almost make up the same size is at least relatively close strength wise?

In short, the goal is to always have hollow piston end always able to push to the screw/harden plastic area at rhst er psi u set and u have to have Belleviews able to support that

 

[nervoustrig]

Hmm, okay yeah it seems unlikely that you would end up with two new regulators, neither of which seems to regulate. Not out of the realm of possibility but it would imply both are defective or built incorrectly _and_ no testing was performed at the factory to check that they work. Other possibilities? Any chance you are accidentally installing them backwards?