Hydraulic Piston Pumps vs. Hydraulic Gear Pumps
17## October 2016
Hydraulic pumps come in different forms to accommodate a range of application requirements, from industrial die presses to heavy-duty off road equipment. One hydraulic system can vary greatly from another. For one system, a hydraulic piston pump may be the best solution, while a hydraulic gear pump may be better suited for a different one.
White House Products, Ltd. offers both types and can help find or design a hydraulic pump for your application; here’s a closer look at each:
What Is a Hydraulic Piston Pump?
Powered by a hydraulic drive, a piston pump has a reciprocating positive displacement design to manage fluid flow. Pistons, or cylindrical elements within a cylinder block, create a vacuum, generated by a drive mechanism, that draws in fluid. The cylindrical chamber is pressurised by distributing energy into the fluid, compressing and forcing it towards the pump’s outlet.
Basic designs can generate about 4,000 psi, but pumps with up to 14,500 psi operating pressure are available. There are many different models that can displace a specific amount of fluid. Some allow you to adjust the displacement per revolution, which can make them more energy efficient. Piston pumps are relatively complex in design and expensive, but practical in energy-efficient applications that require high pressures and effective oil flow control.
What Is a Hydraulic Gear Pump?
A hydraulic gear pump is a lower-cost option, but it is quite durable, with many options available. The typical pressure rating is about 3,000 psi, but many displacement sizes and pressures can be found. Some gear pumps are rated as high as 4,500 psi, although additional valves will be needed in systems that require regular flow adjustments.
Gear pumps function by drawing fluid between their meshing gears. The adjacent gear teeth form chambers that are enclosed within the housing and pressure plates. A partial vacuum forms at the inlet where the gear teeth unmesh, allowing fluid to fill the space and be moved along the outer edge of the gears; as the gear teeth mesh again, fluid is forced out of the pump.
Both pumps use hydraulic fluid to transfer energy or generate mechanical force. Hydraulic piston pumps rely on reciprocating motion. Rotational forces are generated along an axis. Fixed and variable displacement pumps are available, as are different types, including axial, inline, bent-axis, plunger, and radial pumps, each with its own unique method of pushing fluid.
On the other hand, gear pumps move fluid via tightly aligned cogs that create suction to draw in and discharge fluid. Pumps with internal or external gears can be used, depending on the application requirements. Lobe, screw, and vane pumps are just some available types. A downside of using gear pumps is that additional devices are needed to control the desired amount of displacement, as they operate on fixed displacement only.
While gear pumps are available in a wide range of displacement sizes and pressures, and they suit various machinery applications, piston pumps offer the benefits of higher pressure ratings and are variable displacement and energy efficient. Rapid cooling means each pump is ready for the next operating cycle and can be serviced soon after shut-off.
Gear pumps typically don’t move more than 50 gallons per minute of fluid. On the other hand, some piston pumps can move hundreds of gallons per minute. Either one has advantages, depending on your hydraulic application.
Choosing the Right Pump for You
Hydraulic pumps are available in different types, sizes, pressure ratings, and other specifications. It is important to choose the right pump for your hydraulic system. Gear pumps are suited for various types of machinery. Piston pumps are often found in oil field and agricultural applications, as well as in heavy-duty construction equipment. They are reliable and efficient, and they resist leakage at high speeds and pressures.
White House Products, Ltd. supplies, repairs, and maintains hydraulic gear pumps and hydraulic piston pumps from leading manufacturers. We can assist you in choosing a pump that meets your application requirements. Start browsing our catalog or register/login to view prices/availability and place an order. Contact us at +44 (0)1475 742500 for more information.
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