So this is kind of like a stirling engine. Would this work?

A box that has a crankshaft, and two connecting rods that is under a vacuum (with no air inside of it.) The connecting rods are facing opposite each other and attached to the crankshaft on one end and then to a diaphragm on the other end which is part of the side of the box. The connecting rods are oriented such that when one connecting rod is fully extended it pushes the diaphragm outwards whilst the other connecting rod pulls its diaphragm it’s connected to inwards towards the inside of the box. The flexibility of the diaphragms and the outside atmospheric pressure and vacuum on the inside causes the reciprocating between the two. I am sure a better material could be used but to visualize the concept imagine the diaphragms are both made of rubber.

not trying to make a perpetual motion machine


I know atmospheric pressure difference wouldn’t provide a ton of power in this setup.

Final thot of night

  • $\begingroup$ Sounds like it will find an equilibrium position and stop. $\endgroup$ – Solar Mike Aug 3 '19 at 4:56
  • $\begingroup$ I think you will see things totally differently if you think a bit before asking a question like this. $\endgroup$ – kamran Aug 3 '19 at 10:21

It would stop with the crankshaft in the middle position: connecting rods angled sideways most, meaning distance between diaphragms shortest - least volume of vacuum.

There's nothing providing work.

Let's reduce the complexity to show how it does nothing.

First, remove the crankshaft, just connect the diaphragms with a single connecting shaft. Should work even better, not bending the connecting shafts sideways, right? No way to transfer work outside, but by itself, should move? If we want to limit the range of motion, we can add a spring at one end.

Next replace diaphragms with piston heads. An equivalent function mechanical component. You have vacuum between the pistons, air outside, the piston heads connected by a shaft.

Next, since they are connected to each other rigidly, but may leak air through gaps in the sides, let's replace the shaft with a pipe the diameter of the pistons, protecting our precious vacuum inside, the pipe sliding against the walls of full metal chassis.

Now we want to expose more surface or the piston to air, so we reduce the size of the chassis, leaving more of the piston exposed... until we've removed the entire chassis, the pressure in the middle of the piston equalized between top and bottom.

And you're left with a plain vacuum tank hanging on a spring. Why would it move again?

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