BLOWER

摘要

The present invention is equipped with: a first impeller (5) provided to the apical end of a drive axis (2); a second impeller (7) provided closer towards the axis-direction base end of the drive axis (2) than the first impeller (5); a first casing (4) that rotatably houses the first impeller (5); and a second casing (6) that rotatably houses the second impeller (7). The size and/or shape of the casings (4) (6) that respectively house each impeller (5)(7) are differentiated so as to make the inner pressure (P1) of the first casing (4) and the inner pressure (P2) of the second casing (6) different. When a mixed gas of air and a combustible gas are passed through the first casing (4) and only air is passed through the second casing (6), the inner pressure (P2) of the second casing (6) surpasses the inner pressure (P1) of the first casing (4).