For truck-mounted hydraulic systems, the most common design in use may be the gear pump. This design can be characterized as having fewer shifting parts, being simple to program, more tolerant of contamination than additional designs and relatively inexpensive. Gear pumps are fixed displacement, also called positive displacement, pumps. This means the same volume of movement is created with each rotation of the pump’s shaft. Gear pumps are rated in conditions of the pump’s optimum pressure rating, cubic inch displacement and maximum input speed limitation.
Generally, gear pumps are used in open center hydraulic systems. Gear pumps trap essential oil in the areas between your tooth of the pump’s two gears and your body of the pump, transportation it around the circumference of the apparatus cavity and then drive it through the outlet slot as the gears mesh. 
Behind the brass alloy thrust plates, or use plates, a small amount of pressurized oil pushes the plates Gear Pump china tightly against the apparatus ends to improve pump efficiency.