Working with pneumatics

Anyone know how to setup a simple air system? I have a pneumatic air cylinder with dual 1/4 inch NPT threads and a 6 inch throw. Ultimately I would like to have the cylinder extend when I flip one switch and release/contract under weight when I flip another switch. Think automotive airbag systems. Anyone know how to wire or plumb something like this up? Ultimately a compressor only option is what I'm looking for as a air tank would add too much weight. Any help would be greatly appreciated! Thanks

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lemonie9 years ago
Automotive 'air' bag systems use metal azides, i.e. they're nitrogen bags. L
I thought they used pellet explosives to detonate them?
Yea, azide pellets I believe. L
NachoMahma9 years ago
. You will need a 3-way solenoid. Pipe it so that the cylinder is vented in the "off" position and pressure is sent to the cylinder in the "on" position (IIRC, that's air to port 1, vent port 2, and cylinder to port 3). Pipe the solenoid to the cylinder port away from the ram and put some kind of filter on the port at the ram end. Without a load, it will probably only need 5-10psig and even that little may produce dangerous operation (put it in a vise before pressuring up and stay out of the way of the ram).
. For the relatively small volume that your cylinder has, just about any source of clean, dry air will work. The pressure you need will depend on how much force you need to produce.
. If you know the ID (inside diameter) of the cylinder, you can compute the force that will be produced - PSI * cross-sectional area (in square inches).