Blowers come in a number of forms of which the most common is the squirrel cage blower.  The common factor is the air is moving perpendicular to the axis of the part that is moving the air.  Typically, the air is drawn in through the side of the unit, turns at low speed to encounter the inside of a spinning cylinder with ribs or vanes around the wall of the cylinder which fling the air out and away where it is captured and aimed through an outlet much smaller than the inlet.  Think of taking an open tin can, drilling a hole in the center of the bottom to take a bolt as an axle and cutting slots up the sides, bending the material of the slots in, then spinning it with a drill.  A variation looks like a plate with ribs running from the center and increasing in height toward the rim, the air being thrown off the rim.   The name squirrel cage comes from the appearance like the tread wheel small rodents use for exercise - I suspect it is not called a hamster tread wheel because that is too precise - or childish. Blowers can have higher output pressures, but not a lot higher and they lose capacity rapidly with increasing pressure.