Constant flow pumps are used to pressurize pressure vessels uncontrolled. This means that the speed of building up a certain pressure in a vessel depends on the vessel volume and the capacity of the pump.
Pumps with a constant flow rate are powered by an oil pump with a constant delivery. By this the intensifier operates with a constant number of cycles per minute and delivers a flow rate which also is almost constant over the total range of the discharge pressure.
Depending on the delivery volume of the pump, gear pumps or axial piston pumps are used. These pumps are carefully selected to withstand the strong variation of load during each cycle of the intensifier.
The oil pump either can be submerged in the tank or mounted to the top of the oil tank. Submerging the oil pump in the tank results in a lower noise level, but may make maintenance of the pump itself more complicated.
An optional feature allows to stop the intensifier for a certain time, while the electric motor continuous running. The intensifier then again can be started against full discharge pressure.