The air supply for the Kilgen organ at the Lakeview Congregational Church is provided by this 5 HP Spencer blower. It is a two-stage machine, meaning that it has two impellers mounted on the motor shaft. The output of the first stage is fed to the iput of the second stage for a further increase in pressure. The air is delivered to the organ at a pressure of 16 inches of water. The highest pressure that the organ uses is 12" water. Pressure regulators in the instrument drop the blower pressure and hold it steady at the design pressure.

Blower pressure is determined by the diameter of the impellers and their rotating speed, and also by the number of impeller stages. The machine is a typical centrifugal blower, with the impellers consisting of steel discs with radial blades attached. The impeller design causes the mass of air in the blower housing to rotate, the resulting centrifugal force (and also the velocity) of the air determine the output pressure.