Gear Pumps are comprised of a fixed casing two (2) or more meshing gears of equal size. Normally one gear is coupled to the drive shaft while the other rums as an idler. The inderaction of the meshing gears and close tolarance of the casing, create the vacuum and the pressure which carry the fluid through the pump. Gear pump are usually bidirectional an produce no pulsation. The fluid being pumped lubricates the close tolerance wear surfaces, therefore this unit should not be allowed to run dr yor be used with abrasive laden liquids.