Roots blower for near field cooling

For air to be delivered through a tube to a 3D printer nozzle needs more pressure than available from an axial or centrifugal fan, but not as much as would be delivered by a piston or diaphragm pump. This simple Roots blower design works well in this application and is able to deliver 15l/min to a nozzle through 1 meter of 8mm bore silicone tubing.