For truck-mounted hydraulic systems, the most typical design in use is the equipment pump. This design is definitely characterized as having fewer shifting parts, being simple to services, more tolerant of contamination than other designs and relatively inexpensive. Gear pumps are set 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 when it comes to the pump’s optimum pressure rating, cubic inch displacement and maximum input speed limitation.
Generally, gear pumps are found in open center hydraulic systems. Gear pumps trap oil 
in the areas between the the teeth of the pump’s two gears and the body of the pump, transport it around the circumference of the apparatus cavity and then drive it through the store slot as the gears mesh. Behind the brass alloy thrust plates, or put on plates, a small amount of pressurized essential oil pushes the plates tightly Gear Pump china against the gear ends to improve pump efficiency.