Explain construction and working of gear pump.

It consists of a pump housing in which a pair of precisely machined meshing gears runs with minimal radial and axial clearance as shown in fig. One of the gears, called a driver, is driven by a prime mover. The driver drives another gear called a follower. As the teeth of the two gears separate, the fluid from the pump inlet gets trapped between the rotating gear cavities and pump housing. The trapped fluid is then carried around the periphery of the pump casing and delivered to outlet port. The teeth of precisely meshed gears provide almost a perfect seal between the pump inlet and the pump outlet. When the driver is rotated by prime mover and driven will also rotate. Thus partial vacuum is created at the inlet of the pump. Fluid is forced to enter into the pump at atmospheric pressure. Fluid is trapped in the pockets between teeth and the casing and carried towards the outlet port.