Why ball valves over sprinkler valves?

Build a homemade water gun or water balloon launcher and tell us about it.
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Titan
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Why ball valves over sprinkler valves?

Post by Titan » Thu Jul 15, 2010 6:52 pm

Why does everyone use ball valves in thier homemades?

Ball valves may have a more direct flow when fully open that allows a better stream of water, but it seems that a lot of people have spend a lot of time and effort to create trigger systems for these, also ball valves are super cheap

Sprinkler valves open in no time and can be easily converted to pnumatic actuation, making a trigger out of a simple air nozzle is much easier than working with springs and wire etc

Just starting a topic for discussion, I could be completely wrong here but I want to get your thoughts

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cantab
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Re: Why ball valves over sprinkler valves?

Post by cantab » Thu Jul 15, 2010 6:56 pm

Possibly because most homemades are primarily built for power, and ergonomics are a secondary consideration.
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Titan
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Re: Why ball valves over sprinkler valves?

Post by Titan » Thu Jul 15, 2010 7:09 pm

If a valve opens faster it's more powerful is it not? (assuming we're talking 2 valves that can each handle the same amount of pressure behind them)

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cantab
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Re: Why ball valves over sprinkler valves?

Post by cantab » Thu Jul 15, 2010 7:40 pm

Opening speed isn't too relevant. Flow rate is what matters, and sprinkler valves tend to be quite narrow inside, restricting the flow. As a rule of thumb, the nozzle should be not more than half the diameter of the narrowest point in the pipework, or performance suffers.
I work on Windows. My toolbox is Linux.
Arsenal:
Super Soaker: XP215, 2xXP220, Liquidator, Aquashock Secret Strike M(odded), Arctic Blast M, CPS1200, CPS2100, SC Power Pak, 3l aquapack, 1.5l aquapack
Water Warriors: Jet, Sting Ray M, Shark, Argon M, Tiger Shark, PulseMaster
Others: Waterbolt, The Blaster, Storm 500, Shield Blaster 2000, generic PR gun, generic backpack piston pumper (broken), 3l garden sprayer M, 10l water carrier:

Titan
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Re: Why ball valves over sprinkler valves?

Post by Titan » Thu Jul 15, 2010 7:47 pm

so basically the issue is the zig-zag that the water has to pass thru, whereas in spudguns the faster opening valve produces a better initial burst of speed, I can deffinately see a water gun losing power after this initial burst due to the flow

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SSCBen
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Re: Why ball valves over sprinkler valves?

Post by SSCBen » Thu Jul 15, 2010 8:04 pm

Opening time is nowhere near as valuable in water guns. When your shot usually lasts several seconds, why bother?

I can see benefit coming from using a faster opening valve for very short duration shots, but there's the other problem.

Ball valves are more direct, reducing energy loss through the valve and forming a more coherent stream as has been explained and this will increase performance. Hasbro noticed this and they call it "Max-D" technology.

There are many possibilities for valve actuation, but I haven't seen many people attempt ideas other than actuating a ball valve in some fashion.

As for why sprinkler valves aren't used... how are you going to refill the pilot chamber? I actually looked into this, but I concluded that unless you have a very large system, one will lose too much air venting the pilot valve for it to be practical.

If you have any ideas to address any shortcomings in any system, I'd be interested in seeing them. :)

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Titan
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Re: Why ball valves over sprinkler valves?

Post by Titan » Thu Jul 15, 2010 8:34 pm

my only reference for this is my use in spud guns, air is obviously going to "reset" a sprinkler valve much faster, I can't help but wonder if we can somehow bore out the ports to the side with the release valve to allow faster resets

this will not solve the directional flow issues at all, even my homemade piston valves would have this issue, so maybe I'm deadended at this point :p

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cantab
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Re: Why ball valves over sprinkler valves?

Post by cantab » Thu Jul 15, 2010 9:06 pm

Aren't sprinkler valves by default electrically operated? I think normally they want 24 volts, but maybe you could make it run off a 9volt battery somehow?
I work on Windows. My toolbox is Linux.
Arsenal:
Super Soaker: XP215, 2xXP220, Liquidator, Aquashock Secret Strike M(odded), Arctic Blast M, CPS1200, CPS2100, SC Power Pak, 3l aquapack, 1.5l aquapack
Water Warriors: Jet, Sting Ray M, Shark, Argon M, Tiger Shark, PulseMaster
Others: Waterbolt, The Blaster, Storm 500, Shield Blaster 2000, generic PR gun, generic backpack piston pumper (broken), 3l garden sprayer M, 10l water carrier:

Titan
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Re: Why ball valves over sprinkler valves?

Post by Titan » Thu Jul 15, 2010 10:34 pm

yes, I ran my last spud gun off 3 - 9v batteries

before converting to pnumatic

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zeda.beta
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Re: Why ball valves over sprinkler valves?

Post by zeda.beta » Fri Jul 16, 2010 4:04 am

Spud guns get their velocity from acceleration down a barrel, water guns get it from the pressure created when the PC is pressurized.
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SSCBen
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Re: Why ball valves over sprinkler valves?

Post by SSCBen » Fri Jul 16, 2010 4:07 am

cantab wrote:Aren't sprinkler valves by default electrically operated? I think normally they want 24 volts, but maybe you could make it run off a 9volt battery somehow?
You could run off 9 volt batteries as Titan said, and I suppose my post didn't consider the possibility. I think electricity should be avoided in water guns unless it's used for the propulsion, though. But it does get around the pilot gas issue.

I was actually thinking about using a QEV before, not a sprinkler valve, as sprinkler valves aren't designed for high flow. I actually don't know what's different about their operation or even if the pilot chamber needs to be refilled.

Ball valves actuated with an air cylinder are one possibility. It has been done before, and I think it would be useful for a weird water gun design I thought of a year(ish) ago. I'll investigate.

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Do not ask me water gun questions by email or PM. Please post the question at the forum. Private questions and suggestions are welcome by PM and email. Also, I do not sell or buy water guns online.

Titan
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Re: Why ball valves over sprinkler valves?

Post by Titan » Fri Jul 16, 2010 1:59 pm

a QEV is basically the same thing as a piston valve and works on the same principles as a sprinkler valve

in this type of valve, water/air is allowed into both chambers of the valve to equalize pressure, the only thing that keeps the valve closed is a small amount of pressure provided by a spring

they don't have to have the pilot chamber "reset" persay, as soon as whatever is allowing the side with the spring to vent is closed it starts to return to the closed position, how long this takes I'm not sure

I think it is possible to make a water gun with a piston style valve or sprinkler valve but the best case scenario the water still has to go from the PC around a 90 degree bend to the barrel

it might be worth $10 to me just to try it out, I had a modified valve sitting around for a while and now I can't find the diaphram for it :p

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