Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 55 users online :: 2 registered, 0 hidden and 53 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Moding a QEV

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
Sponsored 
  • Author
    Message

Moding a QEV

Unread postAuthor: irisher » Tue Apr 27, 2010 5:40 pm

For a repeating pneumatic I plan on using a QEV. I have heard that for them to repeat a hole on the piston/diaphragm and a spring is required. I think I have the spring part down but, I'm having trouble getting my head around the need for the hole. I would appreciate it if someone would explain the purpose . (I'm using a 1/2" deltrol diaphragm QEV from McMaster Link)
  • 0

Last edited by irisher on Tue Apr 27, 2010 6:00 pm, edited 1 time in total.
User avatar
irisher
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 420
Joined: Mon Dec 29, 2008 2:53 am
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Tue Apr 27, 2010 5:44 pm

If you're filling from the pilot side, you don't need an equalisation hole, but if the air is coming from the chamber side, you need a hole to let air get in behind the piston/diaphragm, and the spring allows this to happen without it firing.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: irisher » Tue Apr 27, 2010 6:00 pm

So if I am filling through pilot I need no modifications?
  • 0

User avatar
irisher
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 420
Joined: Mon Dec 29, 2008 2:53 am
Reputation: 0

Unread postAuthor: Gun Freak » Tue Apr 27, 2010 6:05 pm

Well, almost everybody fills through the pilot, and nobody mods it, so if you gonna fill through pilot, no.
  • 0

OG Anti-Hybrid
One man's trash is a true Spudder's treasure!
Golf Ball Cannon "Superna"M16 BBMGPengunHammer Valve Airsoft SniperHigh Pressure .22 Coax
Holy Shat!
User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Unread postAuthor: jackssmirkingrevenge » Tue Apr 27, 2010 6:07 pm

irisher wrote:So if I am filling through pilot I need no modifications?


Just make sure that your pilot valve has a much better flow than the connection you're feeding through, otherwise it will never fire...
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: Technician1002 » Tue Apr 27, 2010 6:41 pm

To prevent messing up a good QEV, use and aquarium or other needle valve and place this external to the QEV. The advantage is it is adjustable unlike a hole in the piston.
  • 0

User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: irisher » Tue Apr 27, 2010 8:38 pm

Assuming a fire extinguisher is serving as chamber, will a QEV with spring and no hole in the diaphragm achieve multiple shots from the tank if the pilot is only momentary open?
  • 0

User avatar
irisher
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 420
Joined: Mon Dec 29, 2008 2:53 am
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: twizi » Tue Apr 27, 2010 8:45 pm

with a hammer valve yes blow gun no
  • 0

dont play with airsofter with 1000$ gun and play with a 5 dollar pair of glasses
User avatar
twizi
Colonel
Colonel
 
Posts: 511
Joined: Thu Nov 27, 2008 9:04 pm
Location: up yours
Reputation: 0

Unread postAuthor: irisher » Tue Apr 27, 2010 8:46 pm

twizi wrote:with a hammer valve yes blow gun no

How about with a 1/4" direct acting solenoid 3-way valve?
  • 0

User avatar
irisher
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 420
Joined: Mon Dec 29, 2008 2:53 am
Reputation: 0

Unread postAuthor: Crna Legija » Tue Apr 27, 2010 11:23 pm

if your making it like polands gun thay you dont need to mod it at all
  • 0

'' To alcohol... The cause of, and solution to, all of life's problems.”
--Homer Simpson

Add me on ps3: wannafuk, 8/11/11 cant wait
User avatar
Crna Legija
Major General
Major General
 
Posts: 2333
Joined: Sun Jul 20, 2008 5:14 am
Location: australia
Reputation: 0

Unread postAuthor: iknowmy3tables » Wed Apr 28, 2010 6:06 am

so you have an external airsource?
  • 0


iknowmy3tables
Major General
Major General
 
Posts: 1558
Joined: Fri Dec 15, 2006 3:57 pm
Location: maryland
Country: United States (us)
Reputation: 0

Unread postAuthor: irisher » Wed Apr 28, 2010 7:20 am

It has a large onboard air tank that will be replenished from an outside airsource.The problem is, if the entire tank is dumped each shot then I will not have enough flow to fill it up before the next shot. If I can not get a QEV to repeat with the 3-way and pilot side filling then my design needs some serious revision.
  • 0

User avatar
irisher
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 420
Joined: Mon Dec 29, 2008 2:53 am
Reputation: 0

Unread postAuthor: Crna Legija » Wed Apr 28, 2010 7:38 am

a QEV + 3way will work and you will not need to mod it at all.
that is why poland like the 3 way idea no need to mess around with your QEV and its more air efficient than a QEV+pop off
  • 0

'' To alcohol... The cause of, and solution to, all of life's problems.”
--Homer Simpson

Add me on ps3: wannafuk, 8/11/11 cant wait
User avatar
Crna Legija
Major General
Major General
 
Posts: 2333
Joined: Sun Jul 20, 2008 5:14 am
Location: australia
Reputation: 0

Unread postAuthor: POLAND_SPUD » Wed Apr 28, 2010 10:23 am

I just want to stress the fact that in real life QEVs are normally used with 3 way valves... QEV stands for Quick Exhaust Valve

they are used to speed up return spreed of a single acting air cylinder... single air cylinders are normally controlled with a 3 way valve.. so in other words:
QEVs were designed to be used with 3 ways

if the entire tank is dumped each shot then I will not have enough flow to fill it up before the next shot.
what sort of pressures and volumes are we talking about ??
you can calculate how much time it takes to fill the chamebr to x pressure if you know the flow of the valve you want to use...

unless you want to build a fullauto gun that uses a lot of air for each shot this shouldn't be a problem
  • 0

Children are the future

unless we stop them now
User avatar
POLAND_SPUD
Chief of Staff
Chief of Staff
 
Posts: 5405
Joined: Sat Oct 13, 2007 4:43 pm
Country: Israel (il)
Reputation: 10

Unread postAuthor: irisher » Wed Apr 28, 2010 4:06 pm

what sort of pressures and volumes are we talking about ??

I plan on Co2/HPA system but, it would be nice for it to work on a fridgy or normal air compressor.Image Here is my setup with AA for size comparison.


unless you want to build a fullauto gun that uses a lot of air for each shot this shouldn't be a problem

Problem is I want a full-auto gun. Although I don't mind having low amounts of air per shot.
  • 0

User avatar
irisher
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 420
Joined: Mon Dec 29, 2008 2:53 am
Reputation: 0

Next

Return to Pneumatic Cannon Discussion

Who is online

Registered users: Bing [Bot], Yahoo [Bot]

Reputation System ©'