SpudFiles

This is a design i am currently working on for nerf/ paintball wars at my house. I have all my parts, but i still have some questions. The lower ball valve is to block off air to the pump, which tends to leak at high pressure. The second ball valve fills the equilization chamber (the area in front of the sprinkler valve), so that i can have multiple shots. I have never tried this before, but i thought that the equilization idea might work. Does anyone have any suggestions? The main chamber is 3" PVC, the equilization chamber is 1" PVC, and the rest is 1/2" PVC. This gun will have interchangeable barrels of 1/2" CPVC and 3/4" CPVC. Thanks in advance for anyone's help!

It's gona take you a while to pump up that chamber with a nerf pump...unless of course your pump on the diagram is a bike pump...

Yes it is a bike pump, and i think it is a pretty good one. I know it might take a while to fill the chamber, but the equilization concept should keep me going for a while before refilling. btw: the only part of this gun related to nerf is the dart in the barrel.

Alright, I get it now...ya this seems like a pretty good idea can't wait to see it finished...

Anyone have any comments about my equilization idea? I know that the pressure will drop with each shot, but i hope that it will stay powerful enough for 5-6 shots before refilling.

That sounds like it would work, ive been toying around with an idea like that for about a month now. and from what i can see it should work

There are several examples of guns on here using a system to meter out the air from a larger chamber to get more shots. In fact I'm pretty sure I've seen a gun virtually identical to yours on another site that a guy made for "office wars". I'm not sure if it had the smaller chamber to fire it though.

Well the only problem with equalization is the fact that you'll have consecutively weaker shots.Meaning, you'll only get two maybe three shots before you'll have to pump the gun up again.I don't know how that works with your playing style but I'd consider a regulator setup.

I don't know what your chamber dimensions are, so I'm just going to provide you with the relevent equations:

PSI_new = (PSI_old + 15) * (Vol_main-chamber / (Vol_main-chamber + Vol_{second-chamber})) - 15

Pressures in PSIG

This gives you the pressure that you'll fill your small chamber to, as well as the pressure remaining in your main chamber after filling it.

You mean like if he put a regulator on the big chamber and then kept the equalization chamber. that would be cool. and that would probably work really well

It wouldn't work connected to the big chamber because for a regulator to work the feed source needs to be at a higher pressure than the part being fed.It works for high pressure tanks but, the bike pump isn't capable of creating the pressure needed.
I was advocating connecting some higher pressure tank.Say a Co2 tank or what not.Still leaving the large resevoir in place.This will eliminate the valve honking when being filled.

pvcmaster wrote:This is a design i am currently working on for nerf/ paintball wars at my house. I have all my parts, but i still have some questions. The lower ball valve is to block off air to the pump, which tends to leak at high pressure. The second ball valve fills the equilization chamber (the area in front of the sprinkler valve), so that i can have multiple shots. I have never tried this before, but i thought that the equilization idea might work. Does anyone have any suggestions? The main chamber is 3" PVC, the equilization chamber is 1" PVC, and the rest is 1/2" PVC. This gun will have interchangeable barrels of 1/2" CPVC and 3/4" CPVC. Thanks in advance for anyone's help!

What troubles me is the air hose (yellow) leeding to the trigger is not blocked off from the pump by the lower ball valve.

Wont the sprinkler valves pilot chamber leak out through the bike pump? Causeing a mis fire. The sprinkler valve will have the same amount of pressure as the main chamber.

Sorry, I should have clarified that. The yellow hose is connected to the sprinkler valve only, and is in no way connected to the bike pump setup(goes behind the gun).

And boilingleadbath, thank you for that equation, i was looking for something like that.

I am going for a simple setup, and i am perfectly fine without a regulator, especially because the pump is mounted on the gun.

Thanks for all your help!

btw: is the second chamber large enough to fire a nerf dart or paintball with sufficient velocity? (5-6" of 1" pvc, at about 50-70 psi)

A nerf dart, probably, with a paintball you'll probably only get about 50 feet maximum.

that is not really sufficient for me. I am looking more around 100-110 ft, so what are some of the changes i could make to accomplish this? Should i increase the pressure, or the secondary chamber?