QEV Cascade
Anyone ever tried cascading 2 or 3 QEVs in a series? It seems to me like it would be useful for piloting a large area with a very small (or slow) valve. I know that using a setup like this would not allow the final pilot volume to be exhausted any faster than with a single properly piloted QEV. So there's no potential for increasing valve speed, but it does seem like it would work very well for minimizing the size (flow) of the valve needed to pilot the entire system. Anyone tried this or have anything to say about it?
- jackssmirkingrevenge
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If the flow is limited, then a slight difference in valve speed isn't really going to make much of a difference in the valve being piloted. A 1" pilot opened at the same speed as a 1/2" pilot will dump air 4 times faster than the smaller valve. You might be able to improve the opening time on the 1/2" by using another QEV to pilot it but the flow restriction remains.
hectmarr wrote:You have to make many weapons, because this field is long and short life
- potatoflinger
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I did something similar a few months ago. My golf ball cannon uses a 1/4" QEV to pilot two 3/4" QEVs that both vent to the barrel. It didn't make a noticeable difference in performance so I wound up just replacing the pilot QEV with a ball valve so that I could use the QEV for something else.
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I think you may have misunderstood, or maybe I'm misunderstanding you.jackssmirkingrevenge wrote:If the flow is limited, then a slight difference in valve speed isn't really going to make much of a difference in the valve being piloted. A 1" pilot opened at the same speed as a 1/2" pilot will dump air 4 times faster than the smaller valve. You might be able to improve the opening time on the 1/2" by using another QEV to pilot it but the flow restriction remains.
I'm not looking to improve opening time or flow, I'm talking about using a smaller QEV to pilot a larger one. And maybe even pilotting the smaller QEV with an even smaller QEV
eg.
Large volume that > 3/4" QEV > 3/8" QEV > 1/8" QEV > Small(Flow restricted) valve
needs pilotted
It seems like a setup like this would allow you to pilot a large volume using a small, low flow valve
- POLAND_SPUD
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yeah I did something like that a couple of days ago... I normally pilot a 1/2" QEV with a 1/8" 3 way valve and there is some noticeable drop in performance when I squeeze the rigger rather than pull it
so I attached the 3 way valve to a 1/8" QEV and that to the main QEV...
and damn it seemed that I gained a few J with this... and the gun seemed more consistent too
I still have to find a good place where I can put the 3 way valve on the gun... the place where it was when attached directly the the piloting side of the QEV was almost ideal
so I attached the 3 way valve to a 1/8" QEV and that to the main QEV...
and damn it seemed that I gained a few J with this... and the gun seemed more consistent too
I still have to find a good place where I can put the 3 way valve on the gun... the place where it was when attached directly the the piloting side of the QEV was almost ideal
Children are the future
unless we stop them now
unless we stop them now
- jackssmirkingrevenge
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What I was saying is that this example:
Or was it a spelling mistake and slavery has not been outlawed in Poland
would not be significantly more powerful than:Large volume > 3/4" QEV > 3/8" QEV > 1/8" QEV > Small(Flow restricted)
Large volume > 3/4" QEV > blowgun
You have this little guy on your launcher?POLAND_SPUD wrote:when I squeeze the rigger
Or was it a spelling mistake and slavery has not been outlawed in Poland
hectmarr wrote:You have to make many weapons, because this field is long and short life
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lol it could have been worse ('N' not 'R')
but blowguns are not 3 way valves... and it's simpler to increase flow of a 3 way valve with the use of a small QEV than to mod a blowgun to act as a 3 way valvewould not be significantly more powerful than:
Large volume > 3/4" QEV > blowgun
Children are the future
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unless we stop them now
- jackssmirkingrevenge
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Hence:POLAND_SPUD wrote:lol it could have been worse ('N' not 'R')
jackssmirkingrevenge wrote:Or was it a spelling mistake and slavery has not been outlawed in Poland
hectmarr wrote:You have to make many weapons, because this field is long and short life
- Brian the brain
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Oh come on JSR..
You squeeze your rigger on a regular basis.
A large QEV piloted by a smaller one piloted by a blowgun
well it works...even when battling constant flow coming in.
More than 2 is not neccesary..picking the right sizes is.
The secondary pilot QEV is usually only added when a larger pilot volume is created in order to place the blowgun in a particular position ( extra plumbing) or when additional systems are attached.
You squeeze your rigger on a regular basis.
A large QEV piloted by a smaller one piloted by a blowgun
well it works...even when battling constant flow coming in.
More than 2 is not neccesary..picking the right sizes is.
The secondary pilot QEV is usually only added when a larger pilot volume is created in order to place the blowgun in a particular position ( extra plumbing) or when additional systems are attached.
Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!
Can't ask for a better compliment!!
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!
Can't ask for a better compliment!!
- jackssmirkingrevenge
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rather than pull it, of courseBrian the brain wrote:You squeeze your rigger on a regular basis
hectmarr wrote:You have to make many weapons, because this field is long and short life
- D_Hall
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You've got more steps in there than you really need, but the general concept of a QEV being used to pilot another QEV which is in turn piloted in any number of ways is not only common around here, it's also done on commercial valves. For example: An Asco 1.5" QEV actually is two valves in one. The 1.5" QEV, obviously, and a 3/8" QEV. All built into the same housing. How you open the 3/8" QEV is up to you, but by design the 1.5" valve is opened by the 3/8" valve.Slauma wrote:eg.
Large volume that > 3/4" QEV > 3/8" QEV > 1/8" QEV > Small(Flow restricted) valve needs pilotted
It seems like a setup like this would allow you to pilot a large volume using a small, low flow valve
I understand that this wouldn't allow for any performance increase. I've never actually been able to pilot a 3/4" QEV with a blowgun though. I've only tried one of those cheap generic ones, but even after modding it for better flow it still wasn't enough to pilot the QEV.jackssmirkingrevenge wrote:What I was saying is that this example:
would not be significantly more powerful than:Large volume > 3/4" QEV > 3/8" QEV > 1/8" QEV > Small(Flow restricted)
Large volume > 3/4" QEV > blowgun
That's exactly the issue I'm having. All the configurations I've tried either work well for piloting but not aesthetically or work aesthetically but have too much plumbing and too much volume to pilot the QEV. Stacking QEVs seemed like it would be a good way to allow some extra plumbing to be added or a smaller pilot to be used without affecting the final performance of the valveBrian the Brain wrote:The secondary pilot QEV is usually only added when a larger pilot volume is created in order to place the blowgun in a particular position ( extra plumbing) or when additional systems are attached.
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What are you doing?? I've had zero problems piloting 3/4" QEVs with off-the-shelf blowguns. Zero modifications beyond throwing the blowgun's flow restrictor away (but I hardly count that as a mod).Slauma wrote:I understand that this wouldn't allow for any performance increase. I've never actually been able to pilot a 3/4" QEV with a blowgun though. I've only tried one of those cheap generic ones, but even after modding it for better flow it still wasn't enough to pilot the QEV.
I wish I had my camera so I could upload a video.
I use the 3/4" QEV to pilot a 2" piston valve (PVC tee). The blowgun is not enough to pilot it with a 3/4"x1/4" adapter connected to a 1/4" tee with the blowgun on one side and a schrader on the other. Do you think this could happen because of lower pressures? I typically only operate it at 20-40 psi.
I use the 3/4" QEV to pilot a 2" piston valve (PVC tee). The blowgun is not enough to pilot it with a 3/4"x1/4" adapter connected to a 1/4" tee with the blowgun on one side and a schrader on the other. Do you think this could happen because of lower pressures? I typically only operate it at 20-40 psi.