I didn't know where else to put this but, I started watching this video and started wondering how exactly they work.
I understand that its a diaphragm pump, so the in and out motion of the spring causes the pumping actions, but what makes the spring move? There's nothing electrical on these small pumps, which means that its got to be activated by some other mechanical means. I'm going to assume that this is somehow tied into the vacuum created by the cylinders, is that correct? Cylinder comes down, creates pressure, compresses the spring moving the diaphragm?