Multi-Shot Cannon - Questions on valves and Gauges

[csgunner]

I haven't tried to make a multi-shot cannon before, and i have some questions.

First off, would this design work? I would close the valve to the barrel, opent the valve to the main air champer, and pressurize the "dead space" Then close the valve to the air chamber and fire by opening the valve to the barrel.

Second, do I need a pressure gauge on both chambers or just one? If just one, which one?

Here's a diagram

[potatoflinger]

The design will work, but probably won't have very much power since it uses a ball valve as a main firing valve.

You only need one pressure gauge, and it could be in either location, since the pressure will equalize and be the same in both chambers.

[jonnyboy]

You should change the ball valve by the barrel to a sprinkler or change the design a little to allow for a piston or qev.

[jimmy101]

In the drawing, both gauges will always read the same thing.

I think you meant to switch the position of the lower gauge and lower ball valve. One gauge reads the main chamber and one reads the working chamber.

Like potatoflinger said, no need for two valves, regardless of where you locate them. One valve on the main resevoir is all you need.

[MaxuS the 2nd]

Like potatoflinger said, no need for two valves, regardless of where you locate them. One valve on the main resevoir is all you need.

You do mean pressure gauges?

[starman]

The second gauge is a little redundant but it might be nice to know if you had a charged shooting chamber or not, independant of tank pressure.

Also you'll need to be sure to always remember to close the tank valve before shooting.

For a real multishot, go for a High Pressure tank and regulator. Everything else can stay the same if you keep shooting pressures reasonable.

[Hubb]

After each shot, you're going to loose power. You see, as pressure equalizes in both chambers after a shot, the pressure is going to be slightly smaller each time. That is, unless, you hook it constantly to a compressor or air source.

As far as the gauge goes, I'd leave it on the main chamber. That way you will be able to read it with the valve open or closed.

[jimmy101]

Like potatoflinger said, no need for two valves, regardless of where you locate them. One valve on the main resevoir is all you need.

You do mean pressure gauges?

ooops

Like potatoflinger said, no need for two gauges, regardless of where you locate them. One gauge on the main resevoir is all you need.

[splttingatms]

For a real multishot, go for a High Pressure tank and regulator. Everything else can stay the same if you keep shooting pressures reasonable.

What are the best materials for a high pressure tank? Could PVC pipe work? And where would you put the regulator?

[starman]

For a real multishot, go for a High Pressure tank and regulator. Everything else can stay the same if you keep shooting pressures reasonable.

What are the best materials for a high pressure tank? Could PVC pipe work? And where would you put the regulator?

I was referring to a CO2 or HPA setup that's common in paintball.

[john bunsenburner]

I highly recomend you invest into a QEV or piston valve if you are going to bother with HP.

@hubb(ster): Well you could have a large piston at the end of you chamber which is connected to a spring which has the same force per unit of area as the air you are using. Like that you will always have the same pressure. But that is very complicated and not worth the trouble