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Subject: 
Re: Analogue Control of Pneumatics
Newsgroups: 
lugnet.build, lugnet.general, lugnet.technic
Date: 
Wed, 21 Mar 2001 14:22:45 GMT
Viewed: 
193 times
  
In real life pneumatic is not used where more than two position is accuired,
and when it is done ither more pneumatic cylinders are placed after each
other to make more fixed positions.
Or there is placed an hydraulic brake on the cylinder to holde it in place.
(an hydraulic brake is bacicly an hydraulic cylinder where an valve either
allow free passage ore close the connection between the two chambers).

The solution my be to make lego hydraulic, by placing the air pump in water
(warning after placing pneumatic elements in water they will not be able to
hold air presure again!)
This will make the movement of the cylinder much slower and when the valve
is turned in middle position it will stop and hold its position.

As Mario typed liquid is not able to compress, whitch means that you either
have to pump all the time or store the pressure somehow. This can be done by
filling an tank halfway up with liquid and halfway air, when pressure is
applied the air will compress, and in that way store the pressure.
I used an lego air tank for this, and since there is no moving parts in the
tank it can be used for air again after it has dryed.

Some other observasions:

  The return air is released in the valve, so when using water the water is
  comming out the same way, meaning something under the valve have to catch
  the water.

The air pump take in air from the middle so it is not enought to put the end
in water.

Pipes, t-joint and air tank can be dryed and used for air again.

Pump, cylinder and valve can't, so be sure to put an mark on them, and store
them for other creations that accuire hydralic control.

If the pipes used are air proof there should not be any danger of leaking
water around the cylinder.

Liqiud are harder to pump than air so an electric pump have to be geared
more down.

And at the end: none of the electric parts are water proof so make sure
there are no leak before putting in the electric, and don't put to much
presure on since the pipes will then jump off.



Message has 2 Replies:
  Re: Analogue Control of Pneumatics
 
This is really interesting. There are definite differences between pneumatic and hydraulic systems. I dreamed of Lego hydraulic systems before, but I have never anything of it. Could you please give more info on what you did with you Lego hydraulic (...) (24 years ago, 21-Mar-01, to lugnet.build, lugnet.general, lugnet.technic)
  Re: Analogue Control of Pneumatics
 
To make LEGO properly hydraulic, some kind of real hydraulic fluid pumping system would be needed. And it would have to take either water or a special hydraulic fluid. I believe it may be possible to achieve control with airflow alone. But I would (...) (24 years ago, 22-Mar-01, to lugnet.build, lugnet.general, lugnet.technic)

Message is in Reply To:
  Re: Analogue Control of Pneumatics
 
"Alvin Telanco" <78of560001@sneakemail.com> wrote (...) like (...) Hi Al, what you ask is not possible because the Lego pneumatic system is, precisely, *pneumatic*. In real life cylinders that are designed for position control are hydraulic and not (...) (24 years ago, 21-Mar-01, to lugnet.build, lugnet.general, lugnet.technic)

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