Differences in Waterjet Pump Technology

11 Mar 2014

Waterjet cutting systems are extremely versatile, able to produce high precision parts at high production speeds and capable of machining both hard materials—such as granite—and soft materials—like rubber—with equal accuracy using the same cutting process.

Waterjet systems rely on ultra high pressure water (up to 60,000 PSI) to cut the material at hand. To achieve this pressure, one of several different water pump technologies may be used.

Crankshaft Pumps

Crankshaft water pumps, also known as direct drive pumps, use alternating pistons to pressurize water. These pistons are connected to a crankshaft, which is itself connected to an electric motor via a belt. Ultimately, this type of pressure pump operates like an extremely high-powered version of a standard pressure washer.

 

Though they are the least expensive style of pump available for waterjet cutting, crankshaft pumps do present several shortcomings. Among them, the pumps cannot be deadheaded—i.e., a continuous flow of high pressure water from the pump is required to prevent system failure. Because of this, these systems require complex plumbing systems with additional high pressure valves to shunt water flow into the cutting tank when the cutting head is disengaged. Additionally, crankshaft pumps generally require more frequent and more extensive maintenance than other pump technologies.

Inline Hydraulic Intensifier Pumps

Inline hydraulic intensifier water pumps utilize hydraulically powered pistons to compress water to the required pressure levels. These pistons oscillate back and forth, controlled by either mechanical or electrical switching mechanisms. A restriction to the water flow—in this case, the cutting head of the waterjet system—ultimately generates the pressure. Pump cycle rates vary depending on the size of the orifice in the cutting head; the larger the orifice, the faster the pump must work to maintain pressure. A holding tank, also known as an attenuator, is also necessary on the output end to reduce pressure variations.

In most models, the hydraulic pump that runs the intensifier device itself is powered by an electric motor, typically ranging from 15 to 150 horsepower. Inline hydraulic intensifier pumps are not as mechanically efficient as crankshaft pumps, but they are generally far more reliable and require less maintenance.

Parallel Hydraulic Intensifier Pumps

These water pumps generate pressure through the same method as their inline counterparts. However, parallel hydraulic intensifier pumps, pioneered by CMS Tecnocut, offer a number of performance advantages. With multiple hydraulic cylinders operating in a parallel fashion, one cylinder is always in compression mode. This minimizes pressure fluctuations and completely eliminates the need for an attenuator vessel. It also greatly improves pump efficiency and reliability.

To learn more about our innovative waterjet cutting systems, or our parallel hydraulic intensifier pump technology, contact CMS North America today!