The valve takes care for the air flow to the flutes. This happens as follows:
An organ role is sliding over the key*, as a result of which the the holes in the key are closed. Because there are holes in the organ roll, air can escape on these places through the key.
1. A hole in the music roll ensure that air can escape through the key.
2. Because of this the valve goes up.
3. As a result of which air can flow in the flute and a sound can be produced.