Woo Vacuum Pump!

[trebuchet03]

So I just aquired a vacuum pump from a friend... on loan

It's a rotary vane type pump that will pull 20"Hg or 25"Hg intermittently.

So, I don't want to fry this pump while vacuum bagging. Therefore, I need a vacuum limit switch. Having very little budget to do this, I'm posting this question to everyone. Any solutions?

Here's the one I came up with... And I do recognize the Rube Goldbergian properties of it. Hook up a syringe to the vacuum lines and on the plunger, hang a weight. Below the weight, place a micro switch. When there's vacuum, the weight hangs above the switch and the pump is off. If the system loses vacuum, the weight falls the switch is closed. This will cost me about $5 (10 cents for syringe and ~$4 for switch), $10 at the most including electrical components.

Diagram



Thoughts, suggestions, alternatives? Anything blatantly obvious I'm missing?

[Mike]

I applaud your art.

[trebuchet03]

Originally Posted by Mike

I applaud your art.

Should I frame it?

[Ryland]

a spring, and a screw would do the same thing as a weight, and could easly be adjusted.

[Silveredwings]

Don't fry the pump, that would suck. oh wait...

but seriously, you could obviously calibrate it by varying the weight. I'd be concerned about the friction of the syringe plunger. Maybe a lubricant would help as long as it doesn't attack the rubber seal.

[Mike]

Originally Posted by trebuchet03

Should I frame it?

I think it belongs on the fridge door.