a little unrelated topic, but seek help from u guys

Build a homemade water gun or water balloon launcher and tell us about it.
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pk_volt123
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a little unrelated topic, but seek help from u guys

Post by pk_volt123 » Fri Mar 24, 2006 8:46 am

Hi everyone. I'm not really a super soaker fan or anything, but I wanted to ask you guys for some help.

Firstly, I'm a robotics student at BCIT, and we've stumbled over a big problem with our final project.

Our goal was lto fill up 32 acrylic tubes with hydraulic oil, and then generate a combination of bubbles from teh bottom of each tube using air to form text letters or whatever.

The biggest problem is that if we don't keep generating bubbles, oil will leak down the bottom tube where we supply air, so we need some kind of check valve. Surely there are check valves out there, but they cost too much (15 bucks each). I was wondering if you guys knew any cheaper home-made or off the shelf components you can buy to fix this leakage problem

thanks guys!

here is a few pictures of teh adapter

Image

the white quick connect will be where teh 2 meter long 1/2" acrylic tube will connect to
the other quick connect tube is the plastic hose for air to go into
Last edited by pk_volt123 on Sun Mar 26, 2006 10:57 pm, edited 1 time in total.

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joannaardway
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Post by joannaardway » Fri Mar 24, 2006 4:07 pm

I'm having trouble visualising exactly what you mean.

Living within the UK, I don't know much about US components, but my belief is that there are unlikely to be any cheaper options that would be effective.

I'm not sure that check valves are what you need though.

I have a suggestion and a question.

If sufficent pressure were constantly applied to the feed, such that it matched the force of the oil down it, would that work?

The question is; Why not have the air feed at the top of the chambers? (Probably some obvious reason, but I can't see it at the moment)

I'm sorry if this is total misunderstanding, but a diagram would help people to advise you.
"Over the hills and far away, she prays he will return one day. As sure as the rivers reach the seas, back in his arms again she'll be." - Over the Hills and far away, Gary Moore

"So many people have come and gone, their faces fade as the years go by. Yet I still recall as I wander on, as clear as the sun in the summer sky" - More than a feeling, Boston

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m15399
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Post by m15399 » Fri Mar 24, 2006 5:22 pm

It needs to fill at the bottom so that it can float up and make letters.

You basically solved the problem yourself. A check valve would work perfectly. Isn't it worth 15 bucks to solve your problem?

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joannaardway
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Post by joannaardway » Fri Mar 24, 2006 8:48 pm

15 bucks for each of 32 seperate chambers = $480 total = a bit expensive. Besides the valves would probably be a bit big (am I right?)

I still say a diagram would be helpful - I am completely confused as to how this is intended to work - perhaps you could provide one?
"Over the hills and far away, she prays he will return one day. As sure as the rivers reach the seas, back in his arms again she'll be." - Over the Hills and far away, Gary Moore

"So many people have come and gone, their faces fade as the years go by. Yet I still recall as I wander on, as clear as the sun in the summer sky" - More than a feeling, Boston

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m15399
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Post by m15399 » Fri Mar 24, 2006 10:13 pm

Oh, 32 valves. That's not good. I'm afraid the only way is a check valve, though.

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SSCBen
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Post by SSCBen » Fri Mar 24, 2006 10:30 pm

Welcome to Super Soaker Central pk_volt123!

I don't understand much about your setup, so if you could provide some sort of diagram or better explanation, I might be able to offer an alternative to using a load of check valves. It does sound like a design change might be able to prevent the oil from moving down into the air chambers from what you have explained, but I'd need to see how everything is oriented before I can determine that.

Check valves can be fairly cheap, especially in bulk. Where I live, 1/2" ID PVC check valves are about $5 each - total cost of $192 if the price was a dollar steeper. On McMaster-Carr, they have some cheaper check valves even. Look around and you might find that your best option would be buying a certain type or style of check valve.

Also, construction of a check valve is fairly simple. You can easily make a very cheap one from just a rubber slit, a small spring (preferable one that is not too powerful), two washers that fairly closely into PVC couplers, and two PVC couplers. To keep everything cheaper, use an internal diameter such as 1/2" ID to save a little money. I constructed a check valve for essentially free for a small project using my leftover parts with this method. This method will probably cost less than a dollar for each check valve, but the quality will not be that of a factory-made check valve.

Let me know if you need a diagram or anything because I could draw one up for you. The design is simple, but I can easily see where a diagram may be required.

Good luck with your project! :)

ben@sscentral.org / Please read this before emailing or PMing me

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.

pk_volt123
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Post by pk_volt123 » Sat Mar 25, 2006 8:19 am

First of all, I'd like to thank you guys for offering help. This problem has been holding us back from getting anything done really!

Keep in mind that check valves require opposite pressure to fully seal the valve. Our counter-pressure only involves a bit of oil and the force of gravity acting onto the check valve if we used one.

Anyways, I drew up a simple picture in paint. It's not that great, but it should be adequate for explaining what the situation is.

The water tube is filled with hydraulic oil. the light blue oval shapes in teh tube are bubbles.

as you can see, we apply air where the the description says

The tube is a lot longer than the picture i drew up because we need to prevent any water from reaching into our pneumatic solenoids.

I thought of using a bike tube schrader valve. But the problem is the spring loaded pin you have to overcome before any air can go through it. This can be done by opening up this valve, and removing the spring, but then again, I don't know how well it will seal against water/oil.


here is the picture
http://members.shaw.ca/bokinator/bubble help.jpgImageImage

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joannaardway
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Post by joannaardway » Sat Mar 25, 2006 2:37 pm

Check valves have a spring to provide the opposite pressure, so there are no problems there.

I'm not sure that a bike valve will be easy to disassemble (but then again, I've never done it), and after you have removed the spring there will be a lack of the opposing pressure, so I'd look elsewhere.
"Over the hills and far away, she prays he will return one day. As sure as the rivers reach the seas, back in his arms again she'll be." - Over the Hills and far away, Gary Moore

"So many people have come and gone, their faces fade as the years go by. Yet I still recall as I wander on, as clear as the sun in the summer sky" - More than a feeling, Boston

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m15399
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Post by m15399 » Sat Mar 25, 2006 5:41 pm

I think the only way to get around this is to make a simple homemade check valve. I can think of a few ways to do this, but I would ask Ben, since he's done it before.

pk_volt123
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Post by pk_volt123 » Sat Mar 25, 2006 6:02 pm

i found this site which shows ou what a schrader valve looks like when it's dissasembled
http://www.geocities.com/cyqlist/valve.html

what i was thinking was taking out the existing spring in the shcrader valve and replace it with a ligher spring so that we can apply pressure to overcome the spring instead of needing a needle to push through the spring in order to apply pressure.



yes, we were thinking of making a homemade checkvalve, but with our lack of building experience, we're not quite sure where to start.

A few of our colleagues have suggested this.

Now we do have a workshop at our school along with CNC machines, so I think this would be very possible.

So please shoot away with any possible designs or solutions

thanks !

:D

quick edit: I've snapped a picture of the adapter
I will try to get a full picture of the setup sometime tomorrow
Last edited by pk_volt123 on Sun Mar 26, 2006 10:58 pm, edited 1 time in total.

pk_volt123
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Post by pk_volt123 » Sat Apr 01, 2006 12:45 am

it's been quite a while now and no replie?s?

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joannaardway
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Post by joannaardway » Sat Apr 01, 2006 11:22 am

I'm nowhere near an expert on homemade check valves.

So far, the best form of homemade anything I've done was an extra external pressure chamber for one of my guns.

That incorporated a special hose connector which had check valve qualities, but that wouldn't be an option to you - it required high pressures to actually force it shut.

All I can really do is comment on what others post here.
"Over the hills and far away, she prays he will return one day. As sure as the rivers reach the seas, back in his arms again she'll be." - Over the Hills and far away, Gary Moore

"So many people have come and gone, their faces fade as the years go by. Yet I still recall as I wander on, as clear as the sun in the summer sky" - More than a feeling, Boston

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