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For those who are willing to dismember their Legos, here's how to make your own one-way valve from the hand pump: (URL) designed by Christophe Masclet from France. To be sure, Chris has some more home-made pneumatics stuff coming up. Btw, the (...) (23 years ago, 16-Dec-99, to lugnet.robotics, lugnet.technic, lugnet.build)
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| | Re: Home-made One-way valve
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(...) stuff. You say it is not possible to use an air tank in the old style circuit, but would it work with two air tanks, one on the high pressure hose and the other on the vaccuum hose, between the pneumatic "diode" and valve? Jennifer (23 years ago, 16-Dec-01, to lugnet.robotics, lugnet.technic, lugnet.build)
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| | Re: Home-made One-way valve
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(...) Difficult to regulate though - as the same pump affects both. When the high pressure one is full & low pressure one needs pumping, it'll keep adding pressure to both (one outside, one inside). You'd have to have some kind of pressure release (...) (23 years ago, 17-Dec-01, to lugnet.robotics, lugnet.technic, lugnet.build)
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| | Re: Home-made One-way valve
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(...) Alas it doesn't work that way at all. The air tanks will definitely not work with the old style pneumatics whatever way you try to incorporate them in (yep, I spent a good hour checking). Now as I understand it, the air tank is meant to store (...) (23 years ago, 18-Dec-01, to lugnet.robotics, lugnet.technic, lugnet.build)
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| | Re: Home-made One-way valve
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(...) you can store the vacuum in the LEGO tank or any other tank for that matter, but the technic pumps will not work for this unless you do a bit of work to figure this out: if you hook an old style pump straight to a valve (dont know which pin (...) (23 years ago, 18-Dec-01, to lugnet.robotics, lugnet.technic, lugnet.build)
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| | Re: Home-made One-way valve
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(...) made (...) hose (...) You store it the same way. A tank can store a vacuum as well as pressure - it's basically equivalent to increasing the pressure outside. This principal was used on many steam trains (and some diesels?), which use vacuum (...) (23 years ago, 18-Dec-01, to lugnet.robotics, lugnet.technic, lugnet.build)
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| | Re: Home-made One-way valve
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(...) ...the whole concept of "storing vacuum" is a little disturbing. :-) Perhaps "lowering the air pressure" in the tank would be a little more reasonable! ---...--- Steve Baker ---...--- Mail : <sjbaker1@airmail.net> WorkMail: <sjbaker@link.com> (...) (23 years ago, 18-Dec-01, to lugnet.robotics)
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| | Re: Home-made One-way valve
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(...) matter, (...) Well said, Steve, I agree. A tank is simply a container whose inner gas (air in this case) can have a different pressure from the one outside. This pressure can be higher or lower than the one of the air in the environment, but (...) (23 years ago, 18-Dec-01, to lugnet.robotics)
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| | Re: Home-made One-way valve
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Instead of pushing a pneumatic switch back and forth, you can use the old non-return valve: (URL) the pump to the middle hole, connect the air tank to the left hole and leave the right hole free. The old style pump will pull air out of the tank and (...) (23 years ago, 18-Dec-01, to lugnet.robotics, lugnet.technic, lugnet.build)
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| | Re: Home-made One-way valve
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(...) Also, the external pressure is usually fairly fixed (atmospheric pressure) and there's a lower limit to the internal pressure (absolute vacuum), but no intrinsic upper limit (though it is limited by the strength of the tank). Therefore a (...) (23 years ago, 18-Dec-01, to lugnet.robotics, lugnet.technic)
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| | Re: Home-made One-way valve
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(...) Yes, you can store vacuum. But all you can store is 1 atmosphere. So a little blue tank with 4 atmospheres has a lot more storage than one with negative 1 atmosphere! Also, it's real hard to make vacuum, in the real world. I once built a (...) (23 years ago, 18-Dec-01, to lugnet.robotics)
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| | Re: Home-made One-way valve
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Alternativeley you can continue using the valve with the old style pump and have an air tank (if you own two) on each side i.e. one that holds the vaccum and one that holds the pressureized air. but... theres still the problem of flipping the valve (...) (23 years ago, 19-Dec-01, to lugnet.robotics, lugnet.technic, lugnet.build)
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| | Re: Home-made One-way valve
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(...) Somehow I'm a bit queasy about this business of "storing vacuum" in a tank. So I checked with the local supplier of industrial gases. If you need a tank of compressed air, that's no problem. But a tankful of vacuum, er that's not listed in the (...) (23 years ago, 20-Dec-01, to lugnet.robotics, lugnet.technic, lugnet.build)
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| | Re: Home-made One-way valve
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(...) I think the reason for that is simply that you can't store very much "vacuum" in a tank. While you can pressurize a tank to several hundred PSI or better, for vacuum you're limited to completely (well, OK, nearly completely) evacuating it--a (...) (23 years ago, 20-Dec-01, to lugnet.robotics)
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c s soh <cssoh@singnet.com.sg> wrote in message news:3C213F4F.CC899E....com.sg... (...) and (...) How about a vacuum flask (thermos), domestic lightbulb, or even CRT (cathode ray tube such) as in your TV or monitor. These all rely on a stored (...) (23 years ago, 20-Dec-01, to lugnet.robotics, lugnet.technic, lugnet.build)
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| | Re: Home-made One-way valve
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(...) Argh! <rant> It's been a long time since domestic lightbulbs were even partially evacuated - these days they are filled with some kind of relatively inert gas. Back in the 1940's and 50's they were partially evacuated - and on some old movies (...) (23 years ago, 20-Dec-01, to lugnet.robotics)
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| | Re: Home-made One-way valve
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In lugnet.robotics, sjbaker1@airmail.net writes: [snipped rant about light-bulbs] (...) Well, since a perfect vacuum has never (AFAIK) been shown to exist anyware (even in space), I guess you're right. However a partial vacuum is easy to "store" and (...) (23 years ago, 20-Dec-01, to lugnet.robotics)
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| | Re: Home-made One-way valve
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(...) a (...) tanks (...) own (...) So, define vacuum as an area of lower pressure than the surrounding environment. I think that satisfies most if not all of your requirements, and is what most people seem to think of when they mention vacuum. Andy (23 years ago, 20-Dec-01, to lugnet.robotics)
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(...) If you had a 1 atmosphere vacuum in a blue LEGO tank and you took it to the bottom of the Mariana Trench you would have about 13,000 atmospheres of vacuum in it. And if you took it out into space you would have *no* atmospheres in it. All this (...) (23 years ago, 20-Dec-01, to lugnet.robotics)
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(...) So you are happy to say that you can increase the amount of vacuum in a sealed tank by placing it at the bottom of a bucket of water? Mmm'K. ---...--- Steve Baker ---...--- Mail : <sjbaker1@airmail.net> WorkMail: <sjbaker@link.com> URLs : (8 (...) (23 years ago, 20-Dec-01, to lugnet.robotics)
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| | Re: Home-made One-way valve
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If the surrounding environment is the same as what should be in the tank if not for the vacuum - since all are partial anyway - the the vacuum doesn't increase. The matter has to be the same. Andy ----- Original Message ----- From: "Steve Baker" (...) (23 years ago, 21-Dec-01, to lugnet.robotics)
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| | Re: motorized pnuematic valve
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Hi, this is my first post on a LEGO newsgroup, so.. ah... I'm a newbie I guess :) (...) (URL) (file size ~ 2 mb) That was my biggest obstacle making this little motorized pump. The parts used to connect the motor to the valve are kind of (...) (22 years ago, 3-Jan-02, to lugnet.robotics, lugnet.technic, lugnet.build)
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| | Re: motorized pnuematic valve
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Sounds interesting, but the link didn't work for me : ( (22 years ago, 5-Jan-02, to lugnet.robotics, lugnet.technic, lugnet.build)
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