Water Valves

[igpay]

Hi,
I was looking to make something like this, http://www.youtube.com/watch?v=CDDI5h8JQE0 But im not sure which type of valve to use. I was thinking of using a pneumatic, but i'm not sure if they work with water. Oh, and i was also wondering if you could hook up multiple pneumatics to a single blowgun so i could trigger them at the same time.
Thanks!

oops, i probably should have put this in the off-topic category, sorry!

[jrrdw]

oops, i probably should have put this in the off-topic category, sorry!

Spudfiles does not have a "off-topic category", there is a non spudgun related section, but no off=topic.

I can't view youtube, my guess would be use a sprinkler valve. They are made for water usage.

Triggering more then one cannon at once can be done, if you can move the volume of air that needs to be moved.

I'll move this thread to the non spudgun related section for you. Wait a second, it's fine here since you talked about a pneumatic cannon.

[rcman50166]

Uhh.. I hope you have a lot of money. I've looked into those things. The valves used on those are custom made. They are typically spring assisted butterfly valves designed to hold the temperature and pressure created by one of those monsters. There is a main valve that propels it and there is a initiating valve that starts the flash boil reaction. I've seen water rocket dragsters that use over 10,000 PSIG @ 900 degrees fareinheit. Dangerous stuff. Be careful.

[daxspudder]

well using something like the video is pointless... the whole key to spudding is to release all the pressure in a very short time, thereby pushing the ammo out of the barrel after all the force behind it is expended... with something like that your ammo will be projected well before most of the power will be spent... unless you use a really really long barrel... btw most guns on this site use parts made for water use... aka sprinkler(as in sprinkles water) valves, and a piston can theoretically be used with water also...

[STHORNE]

you would need some type of remote actuating regulator (unless you want your hand blown off) and some dangerously high pressures to accomplish something like that.

good luck though :thumbup:

[Lentamentalisk]

well using something like the video is pointless... the whole key to spudding is to release all the pressure in a very short time, thereby pushing the ammo out of the barrel after all the force behind it is expended... with something like that your ammo will be projected well before most of the power will be spent... unless you use a really really long barrel... btw most guns on this site use parts made for water use... aka sprinkler(as in sprinkles water) valves, and a piston can theoretically be used with water also...

Ok, wrong...
A) If this is being used as a sort of car propulsion, which it sounds like he wants, then a long "burn" is good.
B) If not, then all you need to do is lower the amount of water there is in there, and it will flash-boil much faster.

[igpay]

Holy Jeezcats Batman!!!

Sorry, i dont think i explained this very well, i wasnt planning on spending thousands on one of those things, i was thinking more like, umm... 2 liter bottles and schrader valves to bring them up to pressur?
I'm fairly light so i thought that i might be able to gain some distance using like, 5 bottles @ 90 PSI maybe?(I'm not trying to get up to 340 Kmph if thats what you were thinking) Oh, and i only suggested Pneumatic valves because i thought i could trigger them all at the same time, so if any other valves would be better, let me know.

[Lentamentalisk]

No, the way that car works is this:
The water gets superheated, to 700+ degrees, and the pressure gets to at least 1000psi generally more in the 5,000-10,000psi range though. When the valve is opened, the water instantly boils, and the flying steam rushes out of the chamber at supersonic speeds.
There is no way to do this with anything but super high rated forged steel or stronger, and we don't have a way of venting it safely on this site, unless you have unlimited access to a very well equipped machine shop.
Superheated water is not something to mess around with either. We have several threads here discussing it, (feel free to search them up) but it is very dangerous. Mythbusters once plugged up a water heater and turned the burner on full blast. After a few minutes the thing shot straight up into the air and had a ridiculous hang time, completely flattening the model house that they built around it. If the tank on that race car were to fail, the driver would die. Make sure to research what ever you do a lot, but I suggest that given you have no clue what you are doing here, you don't attempt it.

[clide]

Sorry, i dont think i explained this very well, i wasnt planning on spending thousands on one of those things, i was thinking more like, umm... 2 liter bottles and schrader valves to bring them up to pressur?

Sounds like you are just trying to make a sideways water rocket. There is a lot of information on the web on how to make water rockets. Google is your friend.

[igpay]

Sounds like you are just trying to make a sideways water rocket. There is a lot of information on the web on how to make water rockets. Google is your friend.

I know that i could find the info about the water rockets on google, but the point is, im trying to figure out which valve to use.

[Lentamentalisk]

a cork will do fine. As stated above, you can't do anything at all alike that car, as it requires very high temperatures and pressures, and not giving a s#!t about your life, so just take a rubber cork, and poke a tiny hole all the way through it, and put a ball pump nozzle through it. Pump it up and you are good.

[socoj2]

Brass ball valve..

but you, are not going to make a Rocket car to MOVE YOU in YOUR garage.. more then like 6-7 feet anyway.

[DYI]

The design in the first post looks doable, and it is a very simple system really. The pressure release valve wouldn't need to take the full steam explosion pressure, and the actual firing valve could be a burst disk triggered by the steam explosion on release of the pressure through the trigger valve.

Actually, this seems like a great propulsion system for the rocket powered Go-kart we're designing

[Lentamentalisk]

...and you guys were worried about the dangers of a tiny little steam cannon?

[igpay]

Ok, one more time...
I DONT want to make some sort of flash-steam monster super rocket thingy. I DO want to make something like this.
Now, usually these types of water rockets are launched off of a stand on the ground, but i was thinking of using them to obtain something like, 500 times less powerful than what was in that video.

Sorry if i didnt explain that well enough before.