What is the function of those Belleville washers?

[seamaster]

What is the function of those Belleville Spring washers inside the LP10 regulator?

To spring what ? Why?

[SlartyBartFast]

To spring what ? Why?

Not familiar with the LP10, but just looked at a parts diagram. It's the spring that sets the cut-off pressure in any regulator.

Those washers IMO are what controls the pressure delivered by the regulator.

[j-team]

To spring what ? Why?

Not familiar with the LP10, but just looked at a parts diagram. It's the spring that sets the cut-off pressure in any regulator.

Those washers IMO are what controls the pressure delivered by the regulator.

100% correct. And its the lower pressure on the big end being able to overcome the higher pressure on the small end that make sit shut off at the preset pressure.

[SlartyBartFast]

This is still my favorite regulator/bolt combination:


With a very good animation:
http://www.zdspb.com/media/tech/animati ... 2_6fps.gif

10m air pistols don't need the same rate of fire though. ;)

[seamaster]

http://www.pilkguns.com/wp-content/uplo ... 10_man.pdf

Are you saying 29.1 Piston assy which has two o-rings on each end is moving inside those spring washers?

Then those 0 rings won't be long lasting then?

[SlartyBartFast]

Are you saying 29.1 Piston assy which has two o-rings on each end is moving inside those spring washers?

There will be very little movement.

From a quick read, the washers are around the shaft of the piston assembly at all times.

[seamaster]

Still don't quite understand why those spring washers are doing there?

If the piston assembly is pinioned by those two o-rings on either end, and not "pistoning" or moving back and fro, why use those spring washers. Or why not just stack those curved washers into same direction? If the function is just to hold piston assembly in place and not exerting any spring tension?

[Gwhite]

Belleville washers provide a tunable spring tension, which allows them to set the low pressure that gets released to fire the pellet. If you stack them up all the same way (>>>>>>) you get an extremely stiff spring. If you alternate them (><><><><) you get a much softer spring. If you mix them you get something in between. I'm not familiar with the exact inner workings of the Steyr regulator, but I know Benelli uses the same Belleville spring set up in the Kites, and I believe other pistols do as well. Another advantage of Belleville springs is that they can provide quite a bit of force in a small space.

The idea is that the spring sets the pressure where the regulator valve opens and closes to control the pressure on the low pressure side. Once the desired pressure is achieved, the combination of that pressure (usually acting on a piston) and the spring force from the Bellevilles closes the valve. The actual motion involved in opening & closing the valve is pretty small, just enough to allow air through.

[SlartyBartFast]

Semester, the pistol only has to move enough to open the orifice and let high pressure gas pass through.

[10M_Stan]

The spring washers are part of the pressure regulator (part 29 - Pressure reducing valve LP-1). From basic hydraulics: a larger area piston at a lower pressure will balance a smaller area piston at a higher pressure - pneumatics operates on the same principle. The Bellville springs are used to tune the regulator, move a very small amount, and provided the air supply is clean and moisture free, will last a very long time along with the o-rings. Steyr has done this before.

[Gwhite]

One thing we discovered with Benelli Kites is that the Belleville springs they use are plain spring steel, and not stainless steel. Somewhere in our team's travels, we must have gotten some moist air, because an overhaul of a few early Kites for a failed seal problem showed rust on the Belleville springs. We normally get our air from a SCUBA shop, and it should be dry enough not to do that...

[seamaster]

http://www.pilkguns.com/wp-content/uplo ... 10_man.pdf

I am still at lost with this pressure decreasing valve.

I can understand trigger release pushing # 18 valve assy pin in, releasing chamber pressure/air. Spring then push the Valve assy back, stopping pressure release.

But I am totally lost with previous posts mentioning pressure decreasing piston assy valve closure. What valve closure? Where does the back up pressure come from to cause this valve closure?

When I tighten the pressure adjusting screw #29.4 into contact with #29.1 piston assy, if the screw is tight, there was not flow of air across. I had to back up just a little bit ("just a few angstroms") to have air flow through that pin hole, then down the two hole on the side of the piston. Does this pressure adjusting screw changes my final velocity? Seems like if I tighten the screw, the pallet chronoed velocity decreases. If I loosen up that screw, velocity seems to increase.

Coming back to my no-understanding of Belleville washers. Are those washers function to keep piston assy and pressure adjusting screw distance constant? In other words, the piston assy position is not constant? Why is it not constant? What is keeping it not constant?

Previous posts talked about pressure decreasing "valve" opening and closing, what valve are you talking about? Please tell the parts on the Steyr diagram. I don't see any valve in the pressure regulator. I see #18 valve assy, but that is way distant down from pressure regulator.

Pressure decreasing regulator has "valve"?

[j-team]

I am still at lost with this pressure decreasing valve.

Then best not loose any sleep over it, just shoot and enjoy.

[SlartyBartFast]

I am still at lost with this pressure decreasing valve.

The washers are springs. The spring force, adjustment screw setting, and the different diameters on the piston determine the gas pressure differential required to push the regulator valve open.

Maybe just accept it works and enjoy shooting.

[ShootingSight]

The dual diameter piston does move back/forth between the o-rings, and is set up so the bellville springs, are pushing the valve open, while low gas pressure acting on the large diameter is pushing the valve shut. In a balanced piston design, the system is set up so that high pressure is pushing equally in both directions on the valve, so this force is cancelled out. This way you get no effect on diminishing cylinder pressure. In a moving base style regulator, the surface that the high pressure is working against is just kept small, to minimize the effect of diminishing cylinder pressure.

Int he attached GIF file, you see the spring (bellville washers) are pushing the valve open, while the intermediate pressure is pushing the valve closed. So the tension on these washers/springs (bellville washers, when stacked accordion style, act as springs, albeit with very little travel) is what regulates the intermediate pressure. It is not a balanced piston design, but it is conceptually easier to understand.

Especially in low-flow situations, the degree of movement of the piston is negligible.

[seamaster]

Thanks, NOW I am losing much less sleep after understanding this.

The question now is how tightly or how loosely should I turn that pressure adjusting screw into the piston end. Enough to allow air to enter piston, but not so far out that screw and piston would not close.

So screw in until screw touching piston, then anti clockwise 1 turn?

And also, the regulator two dot cover, how tightly do I tighten that cover onto regulator?
Tight (sunken slightly into regulator tip) or loosely making it flat on tip of regulator?

[wasatch]

Why do you want to change the regulator setting? Did you disassemble it?

In general, without a regulator tester or having noted the number of turns in on the adjusting screw you'll have a fun time getting it set correctly.
Iirc the regulator set point on pistols is 90-95 bar. Does that sound correct?
Then final velocity is adjusted via hammer spring tension.
Regulator and hammer spring are typically set in a balanced manner resulting in the desired velocity with best efficiency and lowest shot to shot speed variation.

[j-team]

Steyr regulators are not adjustable.

I think you are looking at the velocity adjusting screw which has nothing to do with the regulator.

The pressure is reduced by the regulator and is held in a second "chamber", the striker hits the valve stem allowing some of the reduced pressure air out of that chamber to the barrel (and as that drops the pressure in that chamber the regulator opens to re fill it). The velocity adjuster just make that striker hit the valve stem harder therefore letting more air out. It does not change the preset pressure that the regulator delivers, that pressure is set by the stack of washers that you first asked about.

You need a chronograph it you want to mess with the velocity sucessfully. Or just go ahead and fiddle.