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How would I make a bidirectional hand pump like an air mattress pump? Answered

I'm looking for a resistance machine like a pneumatic  air mattress pump; two types. One pump could handle maybe 120 pounds pressure. The other would be for about 80 pounds.


I took apart an air mattress pump.
4 valves like you mention frollard. 2 air intake on either ends and 2 valves allowing air into pump handle and out.
Do you think ball bearings would work rickharris instead of rubber valves?

Now I need a place to fabricate the pump case; one about 24 inches long and one about 36 inches long.

Any ideas on where?
Thank you for your feedback.

Ball valves will work if you make them well. IF you try - When you have drilled the ball seat put in a ball bearing and with a suitable punch give it a god tap to bed down the seating of the valve and make it fit the ball profile better - then change the ball for a new one.

No idea where you are so no idea where you might make it - I would do it in my garage. all you need is hand tools.

PS you don't tell us what the pump is for so we have only answered your direct question - More information may result in better suggestions.

Do you need to pump pressure or volume.

EG. You can buy electric pumps that work from a car battery at moderate pressures but low volume.

Something like this - The pump pumps on the up and down stroke. This could be made from drainage pipe and the valves made from flaps of leather.

air pump.jpg

+1, except it will need an 'in' valve on the bottom of the main cylinder or you can't lift the piston.

If you want to get very techi you can make ball valves like this - all you need is a suitable bolt and ball bearing and 2 different sized drills.

bolt valve.jpg

it's gonna be a cylinder with 4 valves, 2 'in' valves on either end of the cylinder allowing air to access either side of the plunger as you do the down press on the other direction; and 2 'out' valves that allow air from both sides of the piston to exit via the hollow stem that you use to pump.

A bicycle pump would work well if modified to have the extra valves, because it can handle the high psi.

Then on the output you have a regulator that prevents air from escaping the system unless a certain pressure is reached - this would provide your resistance.