The blower include an impeller and a side channel formed with a semi-circular side wall, having an inlet and outlet. As the impeller rotates, the air between the impeller blades is radially and circumferentially accelerated and pushed into the side channel. Here it is rther compressed and forced back towards the impeller blades where the air is rther accelerated. As air is transported along a spiral path through the impeller and side channel, each impeller blade increases the compression and acceleration until the air reaches the point where the side channel is connected to the discharge flange, where it is discharged. This type of blower is also referred to by other names such as Regenerative blower, Ring Compressor, Ring Blower or Vortex Blower.