Diaphragm pumps
I try once something technical.
In the home aquarium diaphragm pumps are used. (Brummer)
Construction:
An electromagnet, U-core. Before the ends of the iron core is a permanent magnet. It covers the open side of the magnetic circuit.
The permanent magnet mounted on a movable lever. He can not touch the iron core, but it moves to the right and left by electrically changing the direction of current (AC, 50 Hz)
Half the length of this lever is the pump body is fastened inside the housing.
The membrane is like a rubber cap. In the middle it has a stylus. Which is connected to the lever.
When the lever is moved, the space changes under the cap.
In the pump are two very simple valves. (A small rubber piece is over a small hole in the ground and is clamped at one end with a rubber stopper.) In the interior of the cap, the inletvalve When the space becomes larger, it opens, and air from the outside flows.
The exhaust valve is under the bottom of the pump. The same valve. If space is limited, it opened and air can into the tube.
The valve rubber are very thin. They shall be easily, or they can not follow the rapid movement. Bicycle tube is too thick. I suppose the rubber glove. (About 8 mm long, 4 mm wide, oval, 0.2 mm thick.)
Other things:
Diaphragm pumps should always be placed above the water level. Because power failure can not occur a water return pulse.
It's good to hang these pumps elastic. Then you do not have the sound transmission.
The air flow is very reduced, when the pressure increases. (The amplitude of the lever is smaller)
Therefore, if a plurality of outputs are connected to a pump and an air comes too little, the other not made narrow. This increases the pressure.
The clogged vents must be freed. New clean air stone ..