Today, two types of intensifier pumps are used in waterjet cutting: linear intensifier pumps and rotary direct drive pumps. Both intensifier and direct drive pumps are capable of reliably delivering ultra-high pressure water, and both have been used successfully in the industry. These two pumps have certain things in common. They both have motors, water filters, control systems, and sensors, among other similarities.
Before we start looking at these two pumps separately, let's look at the differences in how the industry defines pressure levels. Note that the pressure ranges follow typical high-pressure pipeline runs (transmission lines, T-shaped, elbows, etc.).
-Low pressure is below 10,000 psi ( 69 MPa ).
-Medium pressure is between 10,000 and 15,000 psi ( 69 to 103 MPa ).
-High pressure is between 15,000 and 40,000 psi ( 103 to 276 MPa ).
-UHP between 40,000 psi and 75,000 psi ( 276 to 517 MPa ) and for waterjet cutting, most pumps between 55-60,000 psi ( 379 to 413 MPa ).
Rotary direct drive pumps
Rotary direct drive pumps were first used for paint removal, mining, and industrial cleaning field applications. Direct drive pumps are used in about 20% of water spray systems installed worldwide. Today, this pump technology is also used in plant cutting and field cleaning applications. Unlike intensifier-based pumps, direct-drive rotary pumps do not have a hydraulic pump. Sometimes called a triplex pump, an electric motor rotates a crank with three pistons to produce ultra-high-pressure water. If you are at all familiar with a pressure washer that is used to clean chewing gum off sidewalks or to wash houses down before painting, consider it the same type of pump.
The main components of the rotary direct drive pump package system are as follows:
-Inlet water treatment to prepare ordinary tap water for the pump.
-A control system to control the pump start/stop, water pressure output, and monitoring the pump integrity by sensors.
- An electric motor between 25 and 500 hp ( 18 and 370 kW ). For waterjet cutting applications, 30 hp ( 22.4 kW ) is the most common.
The power unit, including crankcase (usually with gearbox) and triplex ultra-high pressure fluid end.
Linear intensifier pumps are the original technology used for waterjet cutting and are the most common. intensifier pumps use the elegant "intensifier principle" to pressurize water. Let's look at how this theory works.
Hydraulic oil is pressurized to a pressure of 3,000 psi (in this example). The low-pressure oil is pushed into the piston cookie, which has a surface area 20 times larger than the high-pressure plunger pushed into the water. Therefore, the 3,000 psi oil pressure is "enhanced" by a factor of twenty to produce 60,000 psi of water pressure. The "intensification principle" or ratio uses the difference in plunger area to intensify or increase pressure.
The main components of a linear intensifier pump package system are as follows:
- Electric motors between 25 and 200 hp ( 18 and 150 kW ). For water jet cutting applications, the most common is 50hp ( 37 kW ).
-The intensifier, which uses the principle of pressurization (as described above) to transfer the energy of the oil to the water.
-A hydraulic pump is connected to the motor, which sends the hydraulic oil to the intensifier.
-A control system to control the pump start/stop, the water pressure output, and the monitoring of the pump integrity through sensors.
-Inlet water treatment to prepare ordinary tap water for the pump.
The real comparison should be left to the expert who sits down with you to review your application. I will provide only a few - general, high-level opinions.
-The intensifier is better suited for applications where the cutting head has many on/off cycles.
-intensifier pumps can provide higher pressures than direct drive pumps.
-Direct drive has higher electrical efficiency. The intensifier has longer maintenance intervals. -The direct drive is smaller in size.
Most importantly, there are advantages and disadvantages to each of these two pump technologies. The purpose of this article is to give you the basics of these pump technologies. When you're ready to add a waterjet, it's best to discuss your specific needs with an expert who has experience with both pump technologies in your application. We are a waterjet intensifier pump supplier, so please feel free to contact us to help you find the right fit for your application and the way it works.
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