Waterjet pumps are specified in either horsepower (HP) or kilowatts (kW) to indicate the size of the electric motor that creates the force to pressurize the water. Engineers will size the hydraulic motor depending upon the water pressure and water output they are trying to achieve.

The most common pumps seen on the market today are intensifier style pumps. A simplified diagram of the intensifier concept is shown below. The pumps use hydraulics to apply a certain amount of oil pressure on one side of a piston of a certain diameter. On the water side of the pump, the diameter of the piston is much smaller. The difference in the surface area between the hydraulic side and the water side gives a multiplication factor, or intensification, to the pressure from the oil side. Most intensifier pumps have an intensification ratio of 20 times. This design will be explained in more detail in the “How it Works” chapter.

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<img class="size-full wp-image-2849 aligncenter" src="http://www.wardjet.com/wp-content/uploads/2021/10/Waterjet-University_Nozzle-n-Orifice-Intensifier-Pump-Chart.jpg" alt="Waterjet University_Nozzle n Orifice Intensifier Pump Chart" width="645" height="284" />