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Subject: 
Re: Pneumatic Questions
Newsgroups: 
lugnet.technic
Date: 
Fri, 18 Nov 2005 23:47:48 GMT
Viewed: 
4496 times
  
In lugnet.technic, Andrew Meyer wrote: “...if you set up a system in which one tank was pressure and one was vacuum, and applied both to a... 90d phase shift 2 cyl engine... so that when one side of a cylinder had pressure applied, the other would be connected to vacuum... this would involve two switches per cyl, instead of one...”

In lugnet.technic, Chio Siong Soh replied: “...if you study how the LEGO pneumatic valve is built you know it’s not going to work... else compressed air and vacuum (?) would be leaking from the tanks all the time.”

Thank you Dr. Soh. I started drawing various diagrams of this hypothetical circuit, and quickly found that it was becoming a perpetual motion machine. Not, or course, in design or mechanics, but in impossibility. I was chasing a chimera. The faster I drew new ideas, the faster they refuted themselves. It was a nice dream, but it requires things that Lego just doesn’t have, namely the sealed switch that has been longed for previously on this site. Thank you, everybody, for your ideas on this mind exercise.

Andrew Meyer



Message has 4 Replies:
  Re: Pneumatic Questions
 
(...) I'm glad if I saved you some bucks. The fourth exhaust port is a necessity (for the cylinders to work) and a nuisance (being inaccessible). I first learned about it from Erik Brok's site. In real-life pneumatics, this port would be brought out (...) (19 years ago, 19-Nov-05, to lugnet.technic)
  Re: Pneumatic Questions
 
(...) It is possible to combine multiple switches into a release-free switch, but they would probably be more load than a single switch used on dual ported piston. Kevin (...) (19 years ago, 19-Nov-05, to lugnet.technic, FTX)
  Re: Pneumatic Questions
 
(...) Hi Andrew, Here is a schematic for an engine that combines pressure and vaccume on both piston faces. (URL) uses the four port switch I described in this thread: (URL) The image shows a compressor and air tanks for having pressure and vaccume (...) (19 years ago, 20-Nov-05, to lugnet.technic, FTX)
  Re: Pneumatic Questions
 
(...) Andrew, It is so interesting that you broached the topic of vaacume/pressure pressure at the same time as the hydraulic question. In many ways they are the same problem. Containment. With vaccume/pressure you need a switch with containable (...) (19 years ago, 21-Nov-05, to lugnet.technic, FTX)

Message is in Reply To:
  Re: Pneumatic Questions
 
(...) Sort of like a DPDT reversing switch arrangement? However, if you study how the LEGO pneumatic valve is built you know it's not going to work. Namely, it has a fourth exhaust port that's inaccessible. You'll have to plug up this port for your (...) (19 years ago, 18-Nov-05, to lugnet.technic, FTX)

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