full-auto system / pneumatic timer circuit / timer valve

[iknowmy3tables]

I like this circut much better then the qev with saftey popoffs, I really didn't dig the uninterrupted input to the pilot, I hope the best

I think the next step would be a fully pneumatic pressure actuated dcv or 3way

[POLAND_SPUD]

I really didn't dig the uninterrupted input to the pilot

hmm now I am lost...

anyway... I think that I could have explained it better back then... so I made this animation of what it looks like in fluidsim (that thing actually simulates it... you can see the direction of flow, pressure and it does a lot more than that)

[iknowmy3tables]

I was referring to qevs with pop offs, man that circuit is kinda confusing, but I already understood it from the description, which is more clear then that diagram

[Simon]

Well, I am curious for changing the valve of the auto timer valve. It can not affect the volt of the timer if modified the timer valve. I also want to modify like in the picture but I am afraid because I don’t know where I start to.

My Sports Timer

[Lockednloaded]

would a system where you use the normal QEV+DCV+Air Cylinder work if you used an electric DCV that is triggered by a pressure switch on the chamber?

[PVC Arsenal 17]

would a system where you use the normal QEV+DCV+Air Cylinder work if you used an electric DCV that is triggered by a pressure switch on the chamber?

That's not a bad suggestion. The switch will turn off more reliably than a pop-off valve which can stay open when air is flowing through, even if at a lower pressure than it's rated for. Still, I think the best possible approach to this is to use a microcontroller and let your code take the b*tchiness and inconsistency out of timers and dedicated circuits and whatnot.

Clippard EVN-3M-6 with pilot manifold attached to a JEV-F2F2:

[LovableAirGuns]

none of the videos work but it looks like it would be a excellent gun

[al-xg]

Same here, Can't see the videos

Grr I want to play with pneumatics again, frustrating.

[POLAND_SPUD]

uhmm that's because I removed them, sorry

would a system where you use the normal QEV+DCV+Air Cylinder work if you used an electric DCV that is triggered by a pressure switch on the chamber?

Yeah, why not but you have to make sure that the switches off with some delay (so that the air cylinder would have time to retract and take the next round from the magazine)

For the before menitoed reason you'd probably need a probably require a timer relay.

What's the point of buying a pressure switch (most of which are expensive) when you can use a timer relay itself to achieve fullauto ?

technically speaking pneumatic timer circuits and valves are pneumatic time relays

[Technician1002]

A simple limit switch on the cylinder can take care of ensuring the cylinder has full stroke cycling. A pair of limit switches on the cylinder and a pressure switch on the chamber should take care of all monitoring needed for full stroke cycling.

It then can operate up to the full speed the air supply will permit.

[POLAND_SPUD]

Yeah, sure... but you might as well get rid of the pressure switch and use two limit switches...

or better yet mechanically link the air cylinder with the stem of a bistable valve in a way that it would switch from one position to the other when the rod reaches fully retracted/extended position

[Technician1002]

Without a pressure switch, the system may still cycle on too low of a pressure resulting in poor operation. A pressure switch ensures operation only when the chamber is up to pressure, not just when the cylinder has returned to the home position.

With a combination of a pressure switch and a limit switch, the next cycle won't start until both the cylinder has returned and the chamber has pressure.

[POLAND_SPUD]

A pressure switch ensures operation only when the chamber is up to pressure, not just when the cylinder has returned to the home position.

It goes without saying.

That and the fact that you can use a one way flow control fitting to slow down the cylinder.

Sure sensing would work but timing would work too. It all comes down to personal preference I guess. I prefer stuff that is adjustable so I choose timing

[POLAND_SPUD]

@ tech sorry for double posting but let me point out that there are switches called reed switches and they can be used with most air cylinders (since most of them have a magnetic insert in the piston)

http://www.about-air-compressors.com/pr ... tches.html

Sure that might not seem as something important but if you consider that reed switches can be gotten for just a couple of $ and they can provide an easy solution for position sensing. Well, at least for me the method seems a lot simpler than limit switches

[Technician1002]

For higher reliability and no contact bounce when using a microprocessor, look into hall sensors. Many come with a switch output and hysteresis so you have no switch bounce. No software de-glitching is required.

Many hall sensors are less expensive than reed switches.