What is the best valve system to use? I'v built several potato luanchers already and i'm wanting to upgrade to a pneumatic cannon.
I'm basically needing a valve that will open and release about 100lb of pressure very quickly the larger the volume the better of course. I'm not going to use pvc pipe but metal piping instead.
The last cannon i made was a bit over sized and blow the end caps off several times and shattered a few. I didnt appreciate this much so i'm moving to metal pipes.
Valve system?
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boilingleadbath
- Staff Sergeant 2
- Posts: 1635
- Joined: Sat Mar 12, 2005 10:35 pm
- Location: Pennsylvania, USA
*exasperated*
Ok, your endcaps where failing because... cleanout plugs are not pressure rated, and infact, are often weakly made. Use something pressure rated - These will be marked with a little "nsf-PW", and sometimes "nsf-61".
(yeah, yeah... nsf-61 doesn't acctually mean it's pressure rated, and is acctually only a water purity standard. They are well built, and nearly identical to nsf-pw fittings - which means "potable water" anyway.)
As to the valve, I'd recomend:
If you don't want to build your own valve; the largest sprinkler valve you can afford, up to about twice the diameter of the barrel you want to use. (they don't have very good flow, so a 1" valve acctually only provides full flow to a 9/16" pipe.)
Or as supha valve... probably equivilent to a 2.5-3" sprinkler, and acctually intended to open fast, unlike sprinklers. (100$ from spudtech.com [don't search for them elsewear - you won't find them, as they are built only by the owner of that site])
Or maybe even a spring-acctuated ball valve. (although you can't acctualy use it out of the box - you'll have to rig up the spring system yourself.)
If you want to build your own valve, I'd reccomend a diaphram or piston valve. A desciption and how they work can be peiced together or found on both this site, and the spudtech forums. A ball valve will work as an exaust.
A very accurate simulator for pnematic cannons can be found <a href="http://www1.iwvisp.com/thehalls/ggdt/">here</a>
Ok, your endcaps where failing because... cleanout plugs are not pressure rated, and infact, are often weakly made. Use something pressure rated - These will be marked with a little "nsf-PW", and sometimes "nsf-61".
(yeah, yeah... nsf-61 doesn't acctually mean it's pressure rated, and is acctually only a water purity standard. They are well built, and nearly identical to nsf-pw fittings - which means "potable water" anyway.)
As to the valve, I'd recomend:
If you don't want to build your own valve; the largest sprinkler valve you can afford, up to about twice the diameter of the barrel you want to use. (they don't have very good flow, so a 1" valve acctually only provides full flow to a 9/16" pipe.)
Or as supha valve... probably equivilent to a 2.5-3" sprinkler, and acctually intended to open fast, unlike sprinklers. (100$ from spudtech.com [don't search for them elsewear - you won't find them, as they are built only by the owner of that site])
Or maybe even a spring-acctuated ball valve. (although you can't acctualy use it out of the box - you'll have to rig up the spring system yourself.)
If you want to build your own valve, I'd reccomend a diaphram or piston valve. A desciption and how they work can be peiced together or found on both this site, and the spudtech forums. A ball valve will work as an exaust.
A very accurate simulator for pnematic cannons can be found <a href="http://www1.iwvisp.com/thehalls/ggdt/">here</a>
I wouldnt recomend makeing a piston valve for your first cannon because they are hard to make and a selenoid would be much easier.
I recomend a 1in in line lawn genie sprinkler valve. You can mod it if you want but i just electric start mine and it will shoot a spud through a 1/4 in piece of pressure treated plywood.
I recomend a 1in in line lawn genie sprinkler valve. You can mod it if you want but i just electric start mine and it will shoot a spud through a 1/4 in piece of pressure treated plywood.
Laz91 have you ever used a sprinkler or piston valve? Proably not the reason I ask is because if you have you will notice a huge difference in performance. They are capable of realesing more air then a ball vavle so therefor they work better becasue the way to improve performance on a pneumatic is to realse the most air at once.
piston valves are easy to make, a barrel sealing valve is even easier, also noone mentioned modding. edit sorry i didnt see the dates sorry.kevl12377 wrote:I wouldnt recomend makeing a piston valve for your first cannon because they are hard to make and a selenoid would be much easier.
I recomend a 1in in line lawn genie sprinkler valve. You can mod it if you want but i just electric start mine and it will shoot a spud through a 1/4 in piece of pressure treated plywood.
