Gear pump uses the meshing of gears to pump fluid by displacement. They are one of the most common types of pumps for hydraulic fluid power applications. Gear pumps are also widely used in chemical installations to pump fluid with a certain viscosity. There are two main variations external gear pumps which use two external spur gears and internal gear pumps which use an external and an internal spur gear. Gear pumps are fixed displacement, meaning they pump a constant amount of fluid for each revolution. Some gear pumps are designed to function as either a motor or pump. For those applications which require precise flow rate control or those which demand higher flow rates than are practical with piston metering products of stainless gear pump systems. It has high precision, reliability and simplicity, their unique design offers virtually pulse less flow. Extremely close tolerances are held, minimizing internal clearances. The pumps are constructed primarily from stainless steel and the positive displacement metering ensures consistent performance.