My first regulator.... that really works

[lloyd-ss]

I took the reg apart and and lightly sanded them with some 1000 grit I had handy.  I was doing this on some white paper and  noticed that there were some very tiny metal flecks imbedded in the surface of some of the Bellville washers.  The flecks all came off. The washed with 409, hot water, dried on white paper.  Checked under a lighted magnifier. Sanded the bore of the tube a little, too, until it felt nice and smooth. Then, using some nitrile gloves I have for nasty stuff, smeared the tiniest amount of moly on all the surfaces and reassembled. 
The recovery speed is a little faster,  but I think the return to the set point is more consistent.
Thanks for that tip.
Lloyd-ss

[rsterne]

I did the same thing with 800 grit and found no difference.... I only sanded the top and bottom edges....

Bob

[QVTom]

How does the Ninja deal with the stiction issue Don't they use an AL housing?
Tom

[rsterne]

The belleville washers dont touch the housing (AFAIK), they only touch the piston and each other.... If the washers are in a single stack, only the edges of the washers touch.... If they are doubled up, then each pair of washers have one entire surface in contact.... I think that slows the response time as I've never really seen the problem before doing that....

Bob

[ichsan]

It works, but still need fine tuning. First i used POM/DELRIN for the valveseat but half the time it didn't close before the pressure was about 25 bars higher than setpoint. After changing to PTFE,  which are a litttle softer it's maybe one of ten where it goes 15-20 bars to high. Haven't had time since I made it, but I think I polished/rounded the valvepibe to much... I made it just 3 weeks ago, and Christmas and familytime is rated higher right now... 
The O-rings are 11,28x1.18(the same as I use for the portpart on my HW100), so it's a tight fit, and the little hanging could also come from this. Even if everything got a little molykote, wiped dry afterwards.

Bent... I have DIY regulator project for my gun. it's 27 mm inner diameter titanium cylinder. So far seems it's work, I mean i can set the regulated pressure on firing chamber from 800 psi to 2000 psi by turning the screw in front the body. The problem is when i pull the the trigger ( i set for 2000 psi) regulated pressure goes to 1800 psi, it should be directly back to 2000 psi but my reg need 20 second to reach 2000 psi again. I have tried to adjust the inlet air on piston from 1,5 mm to 4 mm, it doesn't work..still 20 second to reach set-point pressure. Do you think this because hard plastic seatvalve..? Any suggestion..?

I dont know how to attach the pic of my reg..

[rsterne]

That is basically what I was finding as well.... a quick surge to nearly setpoint, and then several seconds to get to the ultimate pressure.... It seems worse with paired (doubled) washers than what you get with single (heavier) bellevilles.... I think the friction between the entire face of the paired washers is an issue....

Bob

[ichsan]

That is basically what I was finding as well.... a quick surge to nearly setpoint, and then several seconds to get to the ultimate pressure.... It seems worse with paired (doubled) washers than what you get with single (heavier) bellevilles.... I think the friction between the entire face of the paired washers is an issue....

Bob

I have used 2 different type of spring (disc spring & coil spring). Both have same symptom, several second to reach ultimate pressure.

[rsterne]

Just thinking about this in a different way.... If the spring rate is very high, then the piston only moves a tiny amount after a shot for a given pressure drop.... That means that the seat is barely uncovered and the flow rate is very low.... so the recovery time is long.... You need a given force to balance the reg at whatever the setpoint pressure is.... but that can be achieved by a high spring rate and a small travel, or by a lower spring rate and a longer travel.... If the rate is lower, the regulator will open further for a given pressure drop, and the flow rate should be higher.... and the recovery faster.... Just a thought....

Bob

[TimmyMac1]

Consistency of recovery pressure obtained and the sensitivity to adjustments can make heavy preloaded arrangements with little travel more problematic. It seems the makers don't double up the washers but go thicker when possible.
All the tanks I test seem to slightly overcharge the after reg chamber when filled so the first few shots can't be trusted. The bigger the chamber the more shots it takes. 5 is plenty to get the Ninja Tank Output stabilized on my rigs.
For those that want to avoid the inevitable Price increase it would be wise to get your tanks and Regs soon as a price increase is gauranteed in the next few weeks. Ninja is considering the purchase of 22 ci tanks from cliff div if the Airgunners support that move with adequate demand. The numbers have to be large to make it happen. Catalina sells vessels but it would be great if Ninja had them in stock with regs.

Only on the GTA.
TimmyMac1

[lloyd-ss]

It seems that we are all seeing the same pattern of operation with these high pressure regulators.  I agree that most of the lag time issue is due to the miniscule flow as the set point is approached.
But I still believe that the change in the o-ring dynamics during a refill situation, or change of set-point causes the inconsistency in the first few shots.  O-rings often misbehave in reciprocating/reversal applications where fine control is required.  Changes in gland depth (deeper) and width (narrower) and material (harder) are usually needed to control the shifting/extrusion of the o-ring in the gland that can be greater than the tolerance of the desired output pressure change  in the regulator. A diaphragm style that eliminates the o-ring movement would behave better, but getting adequate movement in a  diaphragm usually means a larger diameter, and more bulk, plus high cost at the pressures we are dealing with. 
Back to my original regulator, I have milled a 1/8 slot lengthwise to expose the edges of the Belville washers, and it is quite interesting to see their behavior in operation.  It makes it painfully obvious that at the set point, with each shot, there is basically no "observable" movement of main piston as the low pressure reservoir refills after each shot.  That last little bit of re-fill (and over-re-fill) has more do with the elasticity and creep of the inlet sealing seat and o-rings than any movement of the Belvilles.
Just my observations.
Lloyd-ss

[rsterne]

If there is "no observable movement", even with the very long stack of Bellevilles in your regulator, the it would appear that the hardest possible seat material for the HP inlet that will still seal would be better.... ANY extrusion of the seat into the (tiny) inlet port would drastically affect the flow....

I wonder about copper on steel?.... can we get pure copper BB's ?

Bob

[lloyd-ss]

Good thought, Bob. Just for clarification, by no observable movement, I meant with the unaided eye.

Another thought.  In normal operation, the piston reaches an equilibrium point and applies only enough pressure to the HPA inlet seat as is required to stop the flow of air. Depending on the seat material, that might be a few pounds, or several. And it will keep leaking, and therefor building up excess pressure, until the shutoff is 100%.  That creep to 100% shutoff is what we are seeing on the pressure gauge and stop watch.  The sealing interface must be perfect.  (*** another thought-- you shoot the bottle down to 2000 psi and the seal at the inlet orifice is fine.  Then you refill to 3000 psi.  I t probably takes a little more force on the seat to to get it to seal at the new 3000 psi.***)
Looking at my design, I see a problem with the adjustable nature of it.  When I make an adjustment, it actually twists the inlet orifice against the sealing seat, which could damage, or at least wear, the seat.  When increasing the pressure set point, this is not too big of a deal because I am backing the pressure off the seat.  But when DECREASING the pressure, unless I bleed the low pressure reservoir first, then tightening the adjustment screw inward will apply a LOT of force to the sealing seat.  I am going to see how to make that inlet orifice non-rotating to eliminate that problem.  There are a couple of other things I don't like about the whole inlet end of the reg that I ought to re-design.  I had resisted, but it is the right thing to do.
Lloyd-ss

[rsterne]

My design has a rotating seat as well.... It's denting the Delrin face on the bottom of the piston, you can see a "bump" in the middle of the donut shaped depression where it is extruding into the hole in the center of the inlet port.... I think in my case a small copper disc replacing the Delrin might be the answer.... I always bleed the regulator no matter which way i'm adjusting it.... I'm afraid of it wearing/tearing the Delrin otherwise....

Bob

[ichsan]

Another thought.  In normal operation, the piston reaches an equilibrium point and applies only enough pressure to the HPA inlet seat as is required to stop the flow of air. Depending on the seat material, that might be a few pounds, or several. And it will keep leaking, and therefor building up excess pressure, until the shutoff is 100%.  That creep to 100% shutoff is what we are seeing on the pressure gauge and stop watch.  The sealing interface must be perfect. 

yes.. I agree the creep to 100% shutoff caused by the leak, the sealing interface not 100% perfect. It's not easy to make a perfect
shutoff valve, because we deal with 200 bar HPA, in another hand piston (seat valve) has no significant force when he hit feed orifice. Yes.. piston is pushed by air pressure in the firing chamber, but the force from disc spring against it.

This is my thought....to reach set point, let says 135 bar
a. Using hard spring means short piston travel to hit feed orifice.
b. Using softer spring means longer piston travel to hit feed orifice.
At point b, after seat valve hit feed orifice, it is easier/faster to have 100% shutoff because with same "creep" of air pressure, piston/seatvalve has more force to make perfect shutoff than point a.  At point a, the force of "creep" will be used against the stronger spring force.

I will try to use softer spring, my reg now has 2 mm piston's travel to hit inlet orifice

I wish you guys.. know what i mean (sorry for my English)

Looking at my design, I see a problem with the adjustable nature of it.  When I make an adjustment, it actually twists the inlet orifice against the sealing seat, which could damage, or at least wear, the seat.  When increasing the pressure set point, this is not too big of a deal because I am backing the pressure off the seat.  But when DECREASING the pressure, unless I bleed the low pressure reservoir first, then tightening the adjustment screw inward will apply a LOT of force to the sealing seat.  I am going to see how to make that inlet orifice non-rotating to eliminate that problem.
Lloyd-ss

I choose to bleed my firing chamber rather than to fix the damage seatvalve

[lloyd-ss]

Ichsan,
Yes, I understand what you are saying. Making regulators that repeat within 2 or 3% is difficult and I have much to learn, but there are so many different approaches..  Your comment about bleeding the air pressure before making adjustments is good, I think.

Here is a website that has lots of drawings of regulators.  Very good reference.
http://www.zdspb.com/tech/misc/maxflo.html