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Subject: 
Re: Home-made One-way valve
Newsgroups: 
lugnet.robotics, lugnet.technic
Date: 
Tue, 18 Dec 2001 22:32:27 GMT
Viewed: 
1155 times
  
In lugnet.robotics, Mario Ferrari writes:
"Steve Baker" <lego-robotics@crynwr.com> wrote:
Jared wrote:

you can store the vacuum in the LEGO tank or any other tank for that • matter,

...the whole concept of "storing vacuum" is a little disturbing.  :-)

Perhaps "lowering the air pressure" in the tank would be a little more
reasonable!

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 there are no conceptual differences between the two cases.
The problem in using tanks for low pressures doesn't come from the tank
itself, but rather from the Lego pump, which is much less efficient in
lowering the air pressure than in increasing it. I suspect that the reason
is because the gasket (hope this is the right term) of the piston tend to
expand under higher pressures, becoming more air-tight, while this doesn't
happen when lowering the pressure.

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 strong tank can potentially store a much higher pressure
differential when storing high pressure than low pressure.

ROSCO



Message is in Reply To:
  Re: Home-made One-way valve
 
(...) 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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