what type of hydraulic pump is most efficient manufacturer
The goal of a hydraulic pump is to move hydraulic fluid through a hydraulic system, acting much like the beating heart of the system. There are two things that all hydraulic pumps have in common: (1) they provide hydraulic flow to other components (e.g., rams, hydraulic motors, cylinder) within a hydraulic system, and (2) they produce flow which in turn generates pressure when there is a resistance to flow. In addition, most hydraulic pumps are motor-driven and include a pressure relief valve as a type of overpressure protection. The three most common types of hydraulic pumps currently in use are gear, piston, and vane pumps.
In a gear pump, hydraulic fluid is trapped between the body of the pump and the areas between the teeth of the pump’s two meshing gears. The driveshaft is used to power one gear while the other remains idle until it meshes with the driving gear. These pumps are what is known as fixed displacement or positive displacement because each rotation of the shaft displaces the same amount of hydraulic fluid at the same pressure. There are two basic types of gear pumps, external and internal, which will be discussed in a moment.
Gear pumps are compact, making them ideal for applications that involve limited space. They are also simple in design, making them easier to repair and maintain. Note that gear pumps usually exhibit the highest efficiency when running at their maximum speed. In general, external gear pumps can produce higher levels of pressure (up to 3,000 psi) and greater throughput than vane pumps.
External gear pumps are often found in close-coupled designs where the gear pump and the hydraulic motor share the same mounting and the same shaft. In an external gear pump, fluid flow occurs around the outside of a pair of meshed external spur gears. The hydraulic fluid moves between the housing of the pump and the gears to create the alternating suction and discharge needed for fluid flow.
External gear pumps can provide very high pressures (up to 3,000 psi), operate at high speeds (3,000 rpm), and run more quietly than internal gear pumps. When gear pumps are designed to handle even higher pressures and speeds, however, they will be very noisy and there may be special precautions that must be made.
External gear pumps are often used in powerlifting applications, as well as areas where electrical equipment would be either too bulky, inconvenient, or costly. External gear pumps can also be found on some agricultural and construction equipment to power their hydraulic systems.
In an internal gear pump, the meshing action of external and internal gears works with a crescent-shaped sector element to generate fluid flow. The outer gear has teeth pointing inwards and the inner gear has teeth pointing outward. As these gears rotate and come in and out of mesh, they create suction and discharge zones with the sector acting as a barrier between these zones. A gerotor is a special type of internal gear pump that eliminates the need for a sector element by using trochoidal gears to create suction and discharge zones.
Unlike external gear pumps, internal gear pumps are not meant for high-pressure applications; however, they do generate flow with very little pulsation present. They are not as widely used in hydraulics as external gear pumps; however, they are used with lube oils and fuel oils and work well for metering applications.
In a piston pump, reciprocating pistons are used to alternately generate suction and discharge. There are two different ways to categorize piston pumps: whether their piston is axially or radially mounted and whether their displacement is fixed or variable.
Piston pumps can handle higher pressures than gear or vane pumps even with comparable displacements, but they tend to be more expensive in terms of the initial cost. They are also more sensitive to contamination, but following strict hydraulic cleanliness guidelines and filtering any hydraulic fluid added to the system can address most contamination issues.
In an axial piston pump, sometimes called an inline axial pump, the pistons are aligned with the axis of the pump and arranged within a circular cylinder block. On one side of the cylinder block are the inlet and outlet ports, while an angled swashplate lies on the other side. As the cylinder block rotates, the pistons move in and out of the cylinder block, thus creating alternating suction and discharge of hydraulic fluid.
Axial piston pumps are ideal for high-pressure, high-volume applications and can often be found powering mission-critical hydraulic systems such as those of jet aircraft.
In a bent-axis piston pump (which many consider a subtype of the axial piston pump), the pump is made up of two sides that meet at an angle. On one side, the drive shaft turns the cylinder block that contains the pistons which match up to bores on the other side of the pump. As the cylinder block rotates, the distances between the pistons and the valving surface vary, thus achieving the necessary suction and discharge.
In a radial piston pump, the pistons lie perpendicular to the axis of the pump and are arranged radially like spokes on a wheel around an eccentrically placed cam. When the drive shaft rotates, the cam moves and pushes the spring-loaded pistons inward as it passes them. Each of these pistons has its own inlet and outlet ports that lead to a chamber. Within this chamber are valves that control the release and intake of hydraulic fluid.
In a fixed displacement pump, the amount of fluid discharged in each reciprocation is the same volume. However, in a variable displacement pump, a change to the angle of the adjustable swashplate can increase or reduce the volume of fluid discharged. This design allows you to vary system speed without having to change engine speed.
When the input shaft of a vane pump rotates, rigid vanes mounted on an eccentric rotor pick up hydraulic fluid and transport it to the outlet of the pump. The area between the vanes increases on the inlet side as hydraulic fluid is drawn inside the pump and decreases on the outlet side to expel the hydraulic fluid through the output port. Vane pumps can be either fixed or variable displacement, as discussed for piston pumps.
Vane pumps are used in utility vehicles (such as those with aerial ladders or buckets) but are not as common today, having been replaced by gear pumps. This does not mean, however, that they are not still in use. They are not designed to handle high pressures but they can generate a good vacuum and even run dry for short periods of time.
There are other key aspects to choosing the right hydraulic pump that goes beyond deciding what type is best adapted to your application. These pump characteristics include the following:
Selecting a pump can be very challenging, but a good place to start is looking at the type of pump that you need. Vane pumps have been largely replaced by compact, durable gear pumps, with external gear pumps working best for high pressure and operating speeds while internal gear pumps are able to generate flow with very little pulsation. However, vane pumps are still good for creating an effective vacuum and can run even when dry for short periods of time. Piston pumps in general are more powerful but, at the same time, more susceptible to contamination.
Whether the pump is needed for the rugged world of mining, the sterile world of food and beverage processing, or the mission-critical aerospace industry, MAC Hydraulics can assist you with selecting, installing, maintaining, and repairing the right pump to meet the needs of your hydraulic system. In the event of a breakdown, our highly skilled technicians can troubleshoot and repair your pump — no matter who the manufacturer happens to be. We also offer on-site services that include common repairs, preventative maintenance, lubrication, cleaning, pressure testing, and setting.
Gear pumps have very few moving parts. They consist of two intermeshing gears. These pumps have a constant flow rate. They operate at pressures generally between 50 and 210 bar. Gear pumps operate at the highest speeds of any pumps at up to 3000-6000 rpm.
In an external-gear pump, only one of the gear wheels, the drive gear, is connected to the drive. The other gear wheel, the driven gear, rotates in the opposite direction, so that the teeth of the rotating gear wheels interlock.
There are also double external-gear pumps, which combine two gear pumps driven by the same coupling shaft. A double external-gear pump has the advantage of supplying two independent hydraulic circuits, and also provides more flow to one circuit.
Which pump you choose for your power unit affects the nature of your HPU builds. Pump choice usually depends on cost, complexity, and performance. There are three major types of pumps to select from: the gear pump, the piston pump, and the vane pump. Below, we’ll get into the specifics of each pump to help you make the best decision for your system.
Gear pumps are usually very economical but hold lower efficiency values. Their efficiency typically drops over time. However, they are quite durable. A pump’s job is to convert incoming mechanical energy into hydraulic energy. The more efficient the pump, the smaller the motor you can choose. Efficiency saves you the most money over time. Traditional spur gear pumps an average of about 80% efficiency, which puts you at a disadvantage over time.
Vane pumps fall between gear pumps and piston pumps when it comes to practicality. They’re more efficient than gear pumps but less efficient than piston pumps. Vane pumps are known for being very quiet, making them ideal for industrial applications. They’re also available with a myriad of control options, like pressure compensation, displacement control, and load sensing. However, Vane pumps usually can’t handle high-pressure circuits.
Piston pumps account for the premium end of the range. These pumps are capable of supporting very high pressure and have infinite methods of control, including pressure compensation, servo control, load sensing, horsepower control, and more. Piston pumps are also incredibly efficient, with many designs being capable of 95% efficiency. The biggest downside to choosing a piston pump is cost. The initial investment will be pricey, and service or repair can be costly as well.
If you’d like more information about choosing the best pump for your HPU design, contact GCC, Inc. today! Our team of experts is ready to help you find a pump that suits your needs.
If you want to offer the best pipe bursting services to your customers, you need the right equipment to power the job. A hydraulic pump is a necessary tool for pipe bursting and your company should have the most powerful lateral bursting system available. Investing in the best hydraulic pump for your company will help you complete jobs in a timely manner and offer dependable power no matter the scope of work.
California-based TRIC Tools is an innovative and leading expert in the trenchless pipe repair and replacement industry. The company specializes in what they refer to as the TRIC formula: simple, modular, compact, and adaptable, and the industry leaders showcase the formula in their line of hydraulic pumps. The TRIC Tools hydraulic pumps are designed for small residential projects or major municipality repairs. When you need to power your pipe bursting job, TRIC Tools has the hydraulic pump to fit your needs.
Hammerhead Trenchless offers three models featuring 3.75 ton, 12 tons and 22 tons of pulling power to handle a wide range of jobs from 1 to 30 inches in diameter. Currently headquartered in Lake Mills, Wisconsin, the trenchless equipment company focuses on installation, repair and replacement of fiber, communication, water, sewer and gas underground infrastructure.
Hydraulic pumps from Power Team come in a wide range of sizes and power. Power Team is a product brand of SPX FLOW Inc., based in Charlotte, North Carolina. The Model 5.5 - Hydraulic Pump is one of the most popular choices when more speed is needed for your lateral system.
TT Technologies is another strong option for hydraulic pumps. The brand’s products are designed for pulling CIPP liners, fold and form liners, conventional and specialty sliplining, CCTV, and cable through innerduct. TT Technologies’ Grundoburst system calls for less power than tradition pipe bursting, as the technology uses a static pipe bursting tool.
Pow-R Mole Trenchless Solutions offers hydraulic power units for residential, commercial, municipalities, and utility applications. Choose from the mini power unit to the diesel power unit, based on the needs of your company.
In a condition-based maintenance environment, the decision to change out a hydraulic pump or motor is usually based on remaining bearing life or deteriorating efficiency, whichever occurs first.
Despite recent advances in predictive maintenance technologies, the maintenance professional’s ability to determine the remaining bearing life of a pump or motor, with a high degree of accuracy, remains elusive.
Deteriorating efficiency on the other hand is easy to detect, because it typically shows itself through increased cycle times. In other words, the machine slows down. When this occurs, quantification of the efficiency loss isn’t always necessary. If the machine slows to the point where its cycle time is unacceptably slow, the pump or motor is replaced. End of story.
In certain situations, however, it can be helpful, even necessary, to quantify the pump or motor’s actual efficiency and compare it to the component’s native efficiency. For this, an understanding of hydraulic pump and motor efficiency ratings is essential.
There are three categories of efficiency used to describe hydraulic pumps (and motors): volumetric efficiency, mechanical/hydraulic efficiency and overall efficiency.
Volumetric efficiency is determined by dividing the actual flow delivered by a pump at a given pressure by its theoretical flow. Theoreticalflow is calculated by multiplying the pump’s displacement per revolution by its driven speed. So if the pump has a displacement of 100 cc/rev and is being driven at 1000 RPM, its theoretical flow is 100 liters/minute.
Actualflow has to be measured using a flow meter. If when tested, the above pump had an actual flow of 90 liters/minute at 207 bar (3000 PSI), we can say the pump has a volumetric efficiency of 90% at 207 bar (90 / 100 x 100 = 90%).
Its volumetric efficiency used most in the field to determine the condition of a hydraulic pump - based on its increase in internal leakage through wear or damage. But without reference to theoretical flow, the actual flow measured by the flow meter would be meaningless.
A pump’s mechanical/hydraulic efficiency is determined by dividing thetheoretical torque required to drive it by the actual torque required to drive it. A mechanical/hydraulic efficiency of 100 percent would mean if the pump was delivering flow at zero pressure, no force or torque would be required to drive it. Intuitively, we know this is not possible, due to mechanical and fluid friction.
Table 1. The typical overall efficiencies of hydraulic pumps, as shown above, are simply the product of volumetric and mechanical/hydraulic efficiency.Source: Bosch Rexroth
Like theoretical flow, theoretical drive torque can be calculated. For the above pump, in SI units: 100 cc/rev x 207 bar / 20 x p = 329 Newton meters. But like actual flow, actual drive torque must be measured and this requires the use of a dynamometer. Not something we can - or need - to do in the field. For the purposes of this example though, assume the actual drive torque was 360 Nm. Mechanical efficiency would be 91% (329 / 360 x 100 = 91%).
Overall efficiency is simply the product of volumetric and mechanical/hydraulic efficiency. Continuing with the above example, the overall efficiency of the pump is 0.9 x 0.91 x 100 = 82%. Typical overall efficiencies for different types of hydraulic pumps are shown in the Table 1.
System designers use the pump manufacturers’ volumetric efficiency value to calculate the actual flow a pump of a given displacement, operating at a particular pressure, will deliver.
As already mentioned, volumetric efficiency is used in the field to assess the condition of a pump, based on the increase in internal leakage due to wear or damage.
When calculating volumetric efficiency based on actual flow testing, it’s important to be aware that the various leakage paths within the pump are usually constant. This means if pump flow is tested at less than full displacement (or maximum RPM) this will skew the calculated efficiency - unless leakage is treated as a constant and a necessary adjustment made.
For example, consider a variable displacement pump with a maximum flow rate of 100 liters/minute. If it was flow tested at full displacement and the measured flow rate was 90 liters/minute, the calculated volumetric efficiency would be 90 percent (90/100 x 100). But if the same pump was flow tested at the same pressure and oil temperature but at half displacement (50 L/min), the leakage losses would still be 10 liters/minute, and so the calculated volumetric efficiency would be 80 percent (40/50 x 100).
The second calculation is not actually wrong, but it requires qualification: this pump is 80 percent efficient at half displacement. Because the leakage losses of 10 liters/minute are nearly constant, the same pump tested under the same conditions will be 90 percent efficient at 100 percent displacement (100 L/min) - and 0 percent efficient at 10 percent displacement (10 L/min).
To help understand why pump leakage at a given pressure and temperature is virtually constant, think of the various leakage paths as fixed orifices. The rate of flow through an orifice is dependant on the diameter (and shape) of the orifice, the pressure drop across it and fluid viscosity. This means that if these variables remain constant, the rate of internal leakage remains constant, independent of the pump"s displacement or shaft speed.
Overall efficiency is used to calculate the drive power required by a pump at a given flow and pressure. For example, using the overall efficiencies from the table above, let us calculate the required drive power for an external gear pump and a bent axis piston pump at a flow of 90 liters/minute at 207 bar:
As you’d expect, the more efficient pump requires less drive power for the same output flow and pressure. With a little more math, we can quickly calculate the heat load of each pump:
No surprise that a system with gear pumps and motors requires a bigger heat exchanger than an equivalent (all other things equal) system comprising piston pumps and motors.
Brendan Casey has more than 20 years experience in the maintenance, repair and overhaul of mobile and industrial equipment. For more information on reducing the operating cost and increasing the...
There are typically three types of hydraulic pump constructions found in mobile hydraulic applications. These include gear, piston, and vane; however, there are also clutch pumps, dump pumps, and pumps for refuse vehicles such as dry valve pumps and Muncie Power Products’ Live PakTM.
The hydraulic pump is the component of the hydraulic system that takes mechanical energy and converts it into fluid energy in the form of oil flow. This mechanical energy is taken from what is called the prime mover (a turning force) such as the power take-off or directly from the truck engine.
With each hydraulic pump, the pump will be of either a uni-rotational or bi-rotational design. As its name implies, a uni-rotational pump is designed to operate in one direction of shaft rotation. On the other hand, a bi-rotational pump has the ability to operate in either direction.
For truck-mounted hydraulic systems, the most common design in use is the gear pump. This design is characterized as having fewer moving parts, being easy to service, more tolerant of contamination than other designs and relatively inexpensive. Gear pumps are fixed displacement, also called positive displacement, pumps. This means the same volume of flow is produced with each rotation of the pump’s shaft. Gear pumps are rated in terms of the pump’s maximum pressure rating, cubic inch displacement and maximum input speed limitation.
Generally, gear pumps are used in open center hydraulic systems. Gear pumps trap oil in the areas between the teeth of the pump’s two gears and the body of the pump, transport it around the circumference of the gear cavity and then force it through the outlet port as the gears mesh. Behind the brass alloy thrust plates, or wear plates, a small amount of pressurized oil pushes the plates tightly against the gear ends to improve pump efficiency.
A cylinder block containing pistons that move in and out is housed within a piston pump. It’s the movement of these pistons that draw oil from the supply port and then force it through the outlet. The angle of the swash plate, which the slipper end of the piston rides against, determines the length of the piston’s stroke. While the swash plate remains stationary, the cylinder block, encompassing the pistons, rotates with the pump’s input shaft. The pump displacement is then determined by the total volume of the pump’s cylinders. Fixed and variable displacement designs are both available.
With a fixed displacement piston pump, the swash plate is nonadjustable. Its proportional output flow to input shaft speed is like that of a gear pump and like a gear pump, the fixed displacement piston pump is used within open center hydraulic systems.
As previously mentioned, piston pumps are also used within applications like snow and ice control where it may be desirable to vary system flow without varying engine speed. This is where the variable displacement piston pump comes into play – when the hydraulic flow requirements will vary based on operating conditions. Unlike the fixed displacement design, the swash plate is not fixed and its angle can be adjusted by a pressure signal from the directional valve via a compensator.
Flow and Pressure Compensated Combined – These systems with flow and pressure compensation combined are often called a load-sensing system, which is common for snow and ice control vehicles.
Vane pumps were, at one time, commonly used on utility vehicles such as aerial buckets and ladders. Today, the vane pump is not commonly found on these mobile (truck-mounted) hydraulic systems as gear pumps are more widely accepted and available.
Within a vane pump, as the input shaft rotates it causes oil to be picked up between the vanes of the pump which is then transported to the pump’s outlet side. This is similar to how gear pumps work, but there is one set of vanes – versus a pair of gears – on a rotating cartridge in the pump housing. As the area between the vanes decreases on the outlet side and increases on the inlet side of the pump, oil is drawn in through the supply port and expelled through the outlet as the vane cartridge rotates due to the change in area.
Input shaft rotates, causing oil to be picked up between the vanes of the pump which is then transported to pump outlet side as area between vanes decreases on outlet side and increases on inlet side to draw oil through supply port and expel though outlet as vane cartridge rotates
A clutch pump is a small displacement gear pump equipped with a belt-driven, electromagnetic clutch, much like that found on a car’s air conditioner compressor. It is engaged when the operator turns on a switch inside the truck cab. Clutch pumps are frequently used where a transmission power take-off aperture is not provided or is not easily accessible. Common applications include aerial bucket trucks, wreckers and hay spikes. As a general rule clutch pumps cannot be used where pump output flows are in excess of 15 GPM as the engine drive belt is subject to slipping under higher loads.
What separates this pump from the traditional gear pump is its built-in pressure relief assembly and an integral three-position, three-way directional control valve. The dump pump is unsuited for continuous-duty applications because of its narrow, internal paths and the subsequent likelihood of excessive heat generation.
Dump pumps are often direct mounted to the power take-off; however, it is vital that the direct-coupled pumps be rigidly supported with an installer-supplied bracket to the transmission case with the pump’s weight at 70 lbs. With a dump pump, either a two- or three-line installation must be selected (two-line and three-line refer to the number of hoses used to plumb the pump); however, a dump pump can easily be converted from a two- to three-line installation. This is accomplished by inserting an inexpensive sleeve into the pump’s inlet port and uncapping the return port.
Many dump bodies can function adequately with a two-line installation if not left operating too long in neutral. When left operating in neutral for too long however, the most common dump pump failure occurs due to high temperatures. To prevent this failure, a three-line installation can be selected – which also provides additional benefits.
Pumps for refuse equipment include both dry valve and Live Pak pumps. Both conserve fuel while in the OFF mode, but have the ability to provide full flow when work is required. While both have designs based on that of standard gear pumps, the dry valve and Like Pak pumps incorporate additional, special valving.
Primarily used on refuse equipment, dry valve pumps are large displacement, front crankshaft-driven pumps. The dry valve pump encompasses a plunger-type valve in the pump inlet port. This special plunger-type valve restricts flow in the OFF mode and allows full flow in the ON mode. As a result, the horsepower draw is lowered, which saves fuel when the hydraulic system is not in use.
In the closed position, the dry valve allows just enough oil to pass through to maintain lubrication of the pump. This oil is then returned to the reservoir through a bleed valve and small return line. A bleed valve that is fully functioning is critical to the life of this type of pump, as pump failure induced by cavitation will result if the bleed valve becomes clogged by contaminates. Muncie Power Products also offer a butterfly-style dry valve, which eliminates the bleed valve requirement and allows for improved system efficiency.
It’s important to note that with the dry valve, wear plates and shaft seals differ from standard gear pumps. Trying to fit a standard gear pump to a dry valve likely will result in premature pump failure.
Encompasses plunger-type valve in the pump inlet port restricting flow in OFF mode, but allows full flow in ON mode lowering horsepower draw to save fuel when not in use
Wear plates and shaft seals differ from standard gear pumps – trying to fit standard gear pump to dry valve likely will result in premature pump failure
Live Pak pumps are also primarily used on refuse equipment and are engine crankshaft driven; however, the inlet on a Live Pak pump is not outfitted with a shut-off valve. With a Live Pak pump, the outlet incorporates a flow limiting valve. This is called a Live Pak valve. The valve acts as an unloading valve in OFF mode and a flow limiting valve in the ON mode. As a result, the hydraulic system speed is limited to keep within safe operating parameters.
Outlet incorporates flow limiting valve called Live Pak valve – acts as an unloading valve in OFF mode and flow limiting valve in ON mode restricting hydraulic system speed to keep within safe operating parameters
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The hydraulic pumps found in virtually all mobile and industrial applications today use pistons, vanes, or gears to create the pumping action that produces flow. Each method features individual characteristics that differentiate it from the others and make it suitable for a particular range of applications.
Piston pumps can have the pistons arranged in a radial or axial fashion. Radial types tend to be specialized for applications requiring very high power, while axial piston pumps are available in a wide range of displacements and pressure capabilities that make them suitable for many mobile and industrial tasks.
Axial-piston pumps consist of a set of pistons that are fitted within a cylinder block and driven by an angled swash plate powered by the input shaft. As the swash plate rotates, the pistons reciprocate in their respective cylinder block bores to provide the pumping action. (Figure 1 above)
Axial-piston pumps are available with the input shaft and pistons arranged coaxially, or with the input shaft mounted at an angle to the piston bores. Bent axis pumps tend to be slightly more volumetrically efficient for technical reasons, but they also tend to be slightly larger for a given capacity and their shape can present packaging difficulties in some applications.
A unique characteristic of a piston-type pump is that the displacement can be changed simply by changing the angle of the swash plate. Any displacement between zero and maximum is easily achieved with relatively simple actuators to change the swash plate angle.
The most commonly encountered vane-type pump generates flow using a set of vanes, which are free to move radially within a slotted rotor that rotates in an elliptical chamber. A typical configuration uses an elliptical cam ring with the rotor spinning within in a cylindrical housing and a pair of side plates to form the pumping chambers. (Figure 2) The changing volume of the cavity between adjacent vanes creates the pumping action as the rotor rotates.
It is possible to vary the displacement of a vane-type pump, but this is not commonly done except for very specialized applications. The majority of the vane-type pumps used in industrial and mobile applications have a fixed displacement.
Vane pumps can be hydraulically balanced, which greatly enhances efficiency. Some designs place the rotating group in a cartridge, which makes them very easy to repair. The entire rotating group is easily removed and replaced by simply removing the back cover, pulling out the old rotating cartridge and replacing it with a new one.
The simplest gear-type pump uses a pair of mating gears rotating in an oval chamber to produce flow. As the gears rotate, the changing size of the chambers created by the meshing and unmeshing of the teeth provides the pumping action. (Figure 3)
Another design uses an external rotating ring with internal gear teeth that mesh with an internal gear as it rotates. As the inner gear rotates, the tooth engagement creates chambers of diminishing size between the inlet and outlet positions to create flow.
A more sophisticated variant of this principle is the gerotor pump, which has a non-concentric inner and outer rotor with different numbers of teeth. As the pair rotates, the changing volume of the space between the rotors creates the pumping action. Replacing the meshing teeth of the gerotor pump with low-friction rolling elements produces a geroter pump.
All gear-type pumps have a fixed displacement. These pumps are relatively inexpensive compared to piston and vane type pumps with similar displacements, but tend to wear out more quickly and are not generally economically repairable.
Piston-type pumps have a very good service life, provided contamination and heat are controlled. They also have the highest pressure ratings, and the significant advantage of variable displacement. This makes them the best choice for applications where high efficiency and high power density are important considerations. The ability to configure piston-type pumps with both pressure sensing and load sensing capabilities is an important advantage, particularly in mobile applications.
Vane-type pumps are widely used in constant flow/constant pressure industrial applications because they are quiet and easily repaired. They also have the unique attribute of allowing a “soft start” because vane-type pumps typically do not achieve full output at speeds below about 600 rpm. This characteristic can significantly reduce the starting current requirements of electric motors driving a vane-type pump which extends motor life.
Gear pumps are very common in constant flow/constant pressure applications on mobile equipment because of their low cost and dirt tolerance. They are also widely used as charge pumps to pressurize the inlets of piston and vane pumps because of their excellent inlet vacuum tolerance.
Sizing a pump is not really dependent on which technology is chosen. In all cases, it is best to start with the load and then work back through the system calculating losses at each point. Once the theoretical pressure and flow characteristics are calculated, the input horsepower requirement can be determined. A 20% safety factor is commonly used in determining the pump input horsepower requirement to account for efficiency losses in the pump.
Mobile applications that may encounter overrunning loads often require special valve plates that alter the stroke of a piston pump more quickly than standard units. Such proper valving reduces the internal forces in the pump allowing it to come out of stroke more quickly to respond to the load condition.
You should also be aware that many pump options often are not listed in manufacturer’s catalog literature. It is always a good policy to consult with the pump manufacturer or your local representative when sizing or selecting a pump for a specific application.
Today’s hydraulic pumps are sophisticated, precision products that will enhance the customer value of the equipment they power. Knowing the characteristics of each of the common pump technologies and selecting the units that deliver the best balance of cost versus performance in your application is the best way to maximize that value.
Piston pumps have the highest pressure capabilities of the three technologies, up to 7250 psi (500 bar) for those in common use, and as high at 10,000 psi (690 bar) for certain specialized units. Vane and gear pumps are commonly limited to pressures up to about 4000 psi (275 bar).
Hydraulic power density is directly related to operating pressure; the higher the pressure the greater the power density. Piston pumps offer the highest power density with vane and gear types following in that order.
Like power density, the conversion ratio of input power to output power is directly related to operating pressure. Piston pumps offer the highest conversion ratio, followed by vane and gear pumps in that order. The ability of piston and vane pumps to be hydraulically balanced is also a factor in their greater conversion efficiency.
No hydraulic component is immune to damage from dirt! But of the three pump technologies, the gear-type is the most dirt tolerant, followed by vane and piston pumps in that order.
Positive inlet pressure is always preferred in hydraulic pump applications to avoid wear and premature failure. However, of the three technologies, gear-type pumps are the most vacuum tolerant handling vacuums up to 10 in.-Hg (254 mm-Hg). Vane-type pumps can handle inlet vacuum up to 6 in.-Hg (152.4 mm-Hg) and piston-type pumps up to 4 in.-Hg (101.6 mm-Hg).
It is worth noting that piston pumps can be significantly quieted by altering the metering notch geometry on the valve plate. Doing so, however, reduces their efficiency. There is no free lunch.
Gear pumps tend to the lightest for a given displacement, followed by vane and piston pumps in that order. Note also that all three types can be “ganged” by stacking multiple sections together. This is more commonly done with gear and vane pumps, but double piston pumps are also available.
Piston and gear pumps tend to offer the greatest range of fluid compatibilities. Note that is it often necessary to de-rate a pump when it is used with non-petroleum fluids.
Fluid compatibility depends on the type of seals, O-rings and materials used in the construction of a pump. It’s best to consult the manufacturer before using any alternative fluids.
Hydraulic systems are in general members of the fluid power branch of power transmission. Hydraulic pumps are also members of the hydraulic power pack/hydraulic power unit family. Hydraulic units are encased mechanical systems that use liquids for hydraulics.
The hydraulic systems that hydraulic pumps support exist in a range of industries, among them agriculture, automotive manufacturing, defense contracting, excavation, and industrial manufacturing. Within these industries, machines and applications that rely on hydraulic pumps include airplane flaps, elevators, cranes, automotive lifts, shock absorbers, automotive brakes, garage jacks, off-highway equipment, log splitters, offshore equipment, hydraulic motors/hydraulic pump motors, and a wide range of other hydraulic equipment.
When designing hydraulic pumps, manufacturers have many options from which to choose in terms of material composition. Most commonly, they make the body of the pump–the gears, pistons, and hydraulic cylinders–from a durable metal material. This metal is one that that can hold up against the erosive and potentially corrosive properties of hydraulic fluids, as well as the wear that comes along with continual pumping. Metals like this include, among others, steel, stainless steel, and aluminum.
First, what are operating specifications of their customer? They must make sure that the pump they design matches customer requirements in terms of capabilities. These capabilities include maximum fluid flow, minimum and maximum operating pressure, horsepower, and operating speeds. Also, based on application specifications, some suppliers may choose to include discharge sensors or another means of monitoring the wellbeing of their hydraulic system.
Next, what is the nature of the space in which the pump will work? Based on the answer to this question, manufacturers will design the pump with a specific weight, rod extension capability, diameter, length, and power source.
Manufacturers must also find out what type of substance does the customer plan on running through the pumps. If the application calls for it, manufacturers can recommend operators add other substances to them in order to decrease the corrosive nature of certain hydraulic fluids. Examples of such fluids include esters, butanol, pump oils, glycols, water, or corrosive inhibitors. These substances differ in operating temperature, flash point, and viscosity, so they must be chosen with care.
All hydraulic pumps are composed in the same basic way. First, they have a reservoir, which is the section of the pump that houses stationary fluid. Next, they use hydraulic hoses or tubes to transfer this fluid into the hydraulic cylinder, which is the main body of the hydraulic system. Inside the cylinder, or cylinders, are two hydraulic valves and one or more pistons or gear systems. One valve is located at each end; they are called the intake check/inlet valve and the discharge check/outlet valve, respectively.
Hydraulic pumps operate under the principle of Pascal’s Law, which states the increase in pressure at one point of an enclosed liquid in equilibrium is equally transferred to all other points of said liquid.
To start, the check valve is closed, making it a normally closed (NC) valve. When the check is closed, fluid pressure builds. The piston forces the valves open and closes repeatedly at variable speeds, increasing pressure in the cylinder until it builds up enough to force the fluid through the discharge valve. In this way, the pump delivers sufficient force and energy to the attached equipment or machinery to move the target load.
When the fluid becomes pressurized enough, the piston withdraws long enough to allow the open check valve to create a vacuum that pulls in hydraulic fluid from the reservoir. From the reservoir, the pressurized fluid moves into the cylinder through the inlet. Inside the cylinder, the fluid picks up more force, which it carries over into the hydraulic system, where it is released through the outlet.
Piston pumps create positive displacement and build pressure using pistons. Piston pumps may be further divided into radial piston pumps and axial piston pumps.
Radial pumps are mostly used to power relatively small flows and very high-pressure applications. They use pistons arranged around a floating center shaft or ring, which can be moved by a control lever, causing eccentricity and the potential for both inward and outward movement.
Axial pumps, on the other hand, only allow linear motion. Despite this, they are very popular, being easier and less expensive to produce, as well as more compact in design.
Gear pumps, or hydraulic gear pumps, create pressure not with pistons but with the interlocking of gear teeth. When teeth are meshed together, fluid has to travel around the outside of the gears, where pressure builds.
External gear pumps facilitate flow by enlisting two identical gears that rotate against each other. As liquid flows in, it is trapped by the teeth and forced around them. It sits, stuck in the cavities between the teeth and the casing, until it is so pressurized by the meshing of the gears that it is forced to the outlet port.
Internal gear pumps, on the other hand, use bi-rotational gears. To begin the pressurizing process, gear pumps first pull in liquid via a suction port between the teeth of the exterior gear, called the rotor, and the teeth of the interior gear, called the idler. From here, liquid travels between the teeth, where they are divided within them. The teeth continue to rotate and mesh, both creating locked pockets of liquid and forming a seal between the suction port and the discharge port. Liquid is discharged and power is transported once the pump head is flooded. Internal gears are quite versatile, usable with a wide variety of fluids, not only including fuel oils and solvents, but also thick liquids like chocolate, asphalt, and adhesives.
Various other types of hydraulic pumps include rotary vane pumps, centrifugal pumps, electric hydraulic pumps, hydraulic clutch pumps, hydraulic plunger pumps, hydraulic water pumps, hydraulic ram pumps, portable 12V hydraulic pumps, hydraulic hand pumps, and air hydraulic pumps.
Rotary vane pumps are fairly high efficiency pumps, though they are not considered high pressure pumps. Vane pumps, which are a type of positive-displacement pump, apply constant but adjustable pressure.
Centrifugal pumps use hydrodynamic energy to move fluids. They feature a rotating axis, an impeller, and a casing or diffuser. Most often, operators use them for applications such as petroleum pumping, sewage, petrochemical pumping, and water turbine functioning.
Electric hydraulic pumps are hydraulic pumps powered by an electric motor. Usually, the hydraulic pump and motor work by turning mechanisms like impellers in order to create pressure differentials, which in turn generate fluid movement. Nearly any type of hydraulic pump can be run with electricity. Most often, operators use them with industrial machinery.
Hydraulic clutch pumps help users engage and disengage vehicle clutch systems. They do so by applying the right pressure for coupling or decoupling shafts in the clutch system. Coupled shafts allow drivers to accelerate, while decoupled shafts allow drivers to decelerate or shift gears.
Hydraulic ram pumps are a type of hydraulic pump designed to harness hydropower, or the power of water, to elevate it. Featuring only two moving hydraulic parts, hydraulic ram pumps require only the momentum of water to work. Operators use hydraulic ram pumps to move water in industries like manufacturing, waste management and sewage, engineering, plumbing, and agriculture. While hydraulic ram pumps return only about 10% of the water they receive, they are widely used in developing countries because they do not require fuel or electricity.
Hydraulic water pumps are any hydraulic pumps used to transfer water. Usually, hydraulic water pumps only require a little bit of energy in the beginning, as the movement and weight of water generate a large amount of usable pressure.
Air hydraulic pumps are hydraulic pumps powered by air compressors. In essence, these energy efficient pumps work by converting air pressure into hydraulic pressure.
Hydraulic pumps are useful for many reasons. First, they are simple. Simple machines are always an advantage because they are less likely to break and easier to repair if they do. Second, because fluid is easy to compress and so quick to create pressure force, hydraulic pumps are very efficient. Next, hydraulic pumps are compact, which means they are easy to fit into small and oddly shaped spaces. This is especially true in comparison to mechanical pumps and electrical pumps, which manufacturers cannot design so compactly. Speaking of design, another asset of hydraulic pumps is their customizability. Manufacturers can modify them easily. Likewise, hydraulic pumps are very versatile, not only because they are customizable, but also because they can work in places where other types of pump systems can’t, such as in the ocean. Furthermore, hydraulic pumps can produce far more power than similarly sized electrical pumps. Finally, these very durable hydraulic components are much less likely to explode than some other types of components.
To make sure that your hydraulic pumps stay useful for a long time, you need to treat them with care. Care includes checking them on a regular basis for problems like insufficient fluid pressure, leaks, and wear and tear. You can use diagnostic technology like discharge sensors to help you with detect failures and measure discharge pressure. Checking vibration signals alone is often not enough.
To keep yourself and your workers safe, you need to always take the proper precautions when operating or performing maintenance and repairs on your hydraulic pumps. For example, you should never make direct contact with hydraulic fluid. For one, the fluid made be corrosive and dangerous to your skin. For two, even if the pump isn’t active at that moment, the fluid can still be pressurized and may potentially harm you if something goes wrong. For more tips on hydraulic pump care and operation, talk to both your supplier and OSHA (Occupational Safety and Health Administration).
Pumps that meet operating standards are the foundation of safe and effective operations, no matter the application. Find out what operating standards your hydraulic pumps should meet by talking to your industry leaders.
The highest quality hydraulic pumps come from the highest quality hydraulic pump manufacturers. Finding the highest quality hydraulic pump manufacturers can be hard, which is why we have we listed out some of our favorites on this page. All of those whom we have listed come highly recommended with years of experience. Find their information nestled in between these information paragraphs.
Before checking out any of these suppliers, we recommend you take some time to jot down your specifications. That way, you will have an easier time figuring out which ones have potential for you and which ones do not. Plus, when you are ready to talk to a supplier, your list will help you steer the conversation. Do not forget to include in your list the nitty-gritty details like your timeline, your budget and your delivery preferences.
Once you have put together you list, get to browsing. Pick out three or four hydraulic pump supply companies to which you’d like to speak, then reach out to each of them. After you’ve spoken with representatives from each company, decide which one will best serve you, and get started on your project.
Since 1935, Muncie® Power Products has been a leading source of mobile power components to the truck equipment industry. In addition to Power Take-Offs and hydraulic motors, Muncie offers directional, pressure and flow control valves as well as system design capabilities. Call us today or visit our website for more information.
FluiDyne is an ISO certified manufacturer of hydraulic pumps, motors & valves. Our promise is to serve and respect the rebuilders and resellers of North America and the global market with high quality new and remanufactured pumps, motors, valves, filters and filter elements.
Having innovative solutions for mission-critical applications makes Hydraulics Technology the preferred. For over 25 years, our impressive list of hydraulic pumps has met the needs of various applications. In assuring the highest quality products to our customers and meeting their expectations, Hydraulics Technology maintains ISO Certification. HTI is ISO 9001:2008 Certified.
Industrial Flow Solutions is a trusted manufacturer of hydraulic pumps and centrifugal pumps. We pride ourselves on our high-quality products and personalized customer service. Various industries we serve include industrial, food & beverage, and medical. All of our products are tested to ensure quality and durability.
AeroControlex began manufacturing pumps in Cleveland, Ohio in 1945. Over the years, AeroControlex has established itself as an industry leader in the production of hydraulic, fuel, lube and scavenge, centrifugal and coolant pumps. Our worldwide customer base demands the highest quality, cost effective products for the most demanding commercial and military applications.
All World Machinery Supply offers high-quality, affordable pumps, motors, and power units from reputable brands like Daikin, Nachi, Eaton, Tokimec, NOP, Grundfos, Yuken, and Fuji . Our team of representatives and engineers can find or cross any pump/mortor to what you are looking for. We can even help you design a custom application suited to your fit your needs.
American Eagle Accessories Group is a manufacturer of truck equipment accessories. These products include: hydraulic-driven air compressors, drawer systems (tool storage), bolt bins (fastener and fitting storage), lube skids, lube trailers, fuel trailers, and utility construction trailers. All of our products are designed and manufactured in the U.S.A.
Founded in 1991, AZ Hydraulic Engineering manufactures high quality air-operated hydraulic pumps serving a broad clientele. We offer hydraulic piston pumps, power units, tank pumps and more with 25 different pressure ranges up to 50,000PSI and a proven track record for reliability and easy, low cost maintenance. AZ Hydraulics is the source for quality hydraulic pumps and friendly customer service.
Barbee Engineered Testing Systems is a manufacturer of hydraulic power units, hydraulic valve testers, air-driven hydraulic piston pumps, high pressure pumps, hydraulic power systems, high pressure systems and more. Our hydraulic pumps are available with up to 30,000 PSI. Check out our website.
Berendsen Fluid Power is one of the largest distributors of pneumatic and hydraulic products in North America. We distribute from quality manufacturers products such as hydraulic pumps, hydraulic motors, hydraulic gear pumps, mixer pumps and more. Visit our website for more information.
Bosch Rexroth is a global leader in manufacturing industrial hydraulics, including proportional and servo valves. Directional control, high response, flow control, pressure relief, pressure reducing, and servo valves name some of our products. Our rugged valves are a perfect fit your electrohydraulic control applications. A variety of models are available for your viewing on our website.
Brand Hydraulics is a leading designer and manufacturer of high-quality hydraulic valves including hydraulic directional control valves, hydraulic flow control valves, hydraulic relief valves, hydraulic selector valves, shuttle valves, pilot check valves, flow dividers and more. Brand also has a line of quality hand-operated hydraulic pumps. Premium hydraulics since 1956.
For 40 years, Bucher Hydraulics, Inc. has specialized in hydraulic systems, including products such as hydraulic motors and hydraulic power units. Applications include concrete pumps, forage wagons, harvesters, lifting devices, recycling machines, door openers, log splitters and many others.
A Cascon hydraulic pump is used in a wide range of OEM equipment market applications. Whether you"re in the aircraft & aerospace, chemical, gas turbine or industrial or mobile markets, our hydraulic pumps and specialty pumps will meet your requirements and provide solutions that an off-the-shelf pump cannot. Contact Cascon, Inc. today for more information!
CAT PUMPS specializes in high pressure pumps, reciprocating pumps, positive displacement pumps, plunger-piston pumps and we also manufacture hydraulic pumps and hydraulic power units. We are an industry-leader in customer service and quality triplex pump design and products.
CLYDEUNION Pumps is one of the world"s leading pump companies - a centre of excellence in Pump Technology, Hydraulic Design and Engineering. We are structured to provide a specific focus on each of our customer"s key markets as well as providing full global aftermarket support. CLYDEUNION Pumps incorporates an accumulation of over 300 years of engineering expertise.
Trust Commercial Group Lifting Products as a wire rope supplier with more than 60 years of experience. The variety of industries The Commercial Group serves with lifting & rigging equipment includes automotive, steel, construction, utilities and government. As a complete full line manufacturer of wire rope slings, chain slings, nylon slings & Slingmax high performance synthetics, you’re covered!
We have over 55 years of experience in manufacturing hydraulic components. CROSS Manufacturing, Inc. distributes hydraulic filters, hydraulic cylinders, hydraulic gear pumps and hydraulic systems worldwide. Our hydraulic systems are used for automotive, agricultural, mining and construction purposes.
D&D Machine & Hydraulics Inc, located in Fort Myers, Florida, is a manufacturer of hydraulically driven, submersible pumping systems that serves the Agricultural, Construction, Industrial, Mining, Petroleum and Municipal markets worldwide. More than 45 years ago, D&D realized the unlimited potential of hydraulics. Since then, D&D has revolutionized the dewatering industry with a series of hydraulically driven pumps that provide the most technologically advanced and precisely engineered features available today. Specifically, D&D builds electric or diesel-driven Power Units and Axial Flow, Trash, Sludge, Slurry/Digester and Mixed Flow pump heads. The flow capacity of these pump heads range from 450gpm to 55,000gpm and heads of 250 feet are attainable. If a standard pump will not meet the performance needed for a special application, D&D’s wide range of specialty pumps can meet your individual requirement.
When the owners acquired D&D, it was a four-employee, custom machine shop that repaired pumps used by local farmers. Shortly thereafter, D&D began to manufacture hydraulic pumps for a local sales and rental company. In the 1980s, as the business grew, D&D began to sell to other customers throughout the country, eventually achieving global recognition.
D&D goes to market via distributors and direct sales channels on every continent. Its growth has continued, and today, through trade publications, advertising, customer referrals and a developing dealer network, new markets and applications are being recognized for its versatile equipment.
For more than 45 years, the D&D name has been associated with product reliability and performance. D&D is determined to carry on its tradition of providing an expertly designed and manufactured product through innovation in modern manufacturing technology. This, coupled with its focus on offering outstanding customer service, make D&D the leader in the dewatering industry.
Danfoss will drive your vehicle transmission to a new level of performance with our Danfoss piston pumps and motors. Designed for intelligent vehicle management systems, our range brings you closer to your goals for reduced fuel consumption and high operator comfort. We deliver components and systems for machine from 15 to 2500 horsepower.
We create hydraulic pumps that can be utilized for standard and specialized purposes. Our high pressure pumps can handle pressures from 3,000 to 15,000 psi with flows of 200 gpm. Our systems can also perform with various fluids including mineral-oils, low-lubricity fire-resistant fluids. We are dedicated to developing the most reliable hydraulic pumps!
Eaton Hydraulics designs, manufactures and markets a comprehensive line of reliable, efficient hydraulic systems and components including hydraulic motors, hydraulic power units and other hydraulic systems. We serve various markets and applications with our quality systems and accessories.
Enerpac is the global leader in high-force tools and equipment used in industrial markets. Our focus is to provide our customers with the most extensive line of products and accessories that maximize force to increase productivity and make work safer and easier to perform. Our comprehensive family of tools and equipment deliver reliable and dependable performance for any industrial segment.
We offer and repair hydraulic pumps and hydraulic motors. As one of the biggest suppliers of hydraulic power units (original or replacement) and a worldwide distributor, we can ship anywhere in the world immediately. Our inventory of motors is immense and our sales staff has years of experience.
Welcome to the Florida Hydraulic Industrial web site. Browse our categories for hydraulic pumps, hydraulic cylinders, hydraulic and industrial hose, including a wide variety of pressure washer hose, all common hydraulic hose fittings.
Flowserve® is the world leading manufacturer of quality hydraulic pumps — air piston pumps, hydraulic water pumps, vane pumps, entire hydraulic systems, plus valve repair. Our products are used by many industries — chemical; hydrocarbon processing; oil and gas; power; water resources.
Fluid Power International provides expertise in hydraulic pump repair & replacement. We specialize in repairing & replacing metric pumps & motors for Japanese and German heavy machinery as well as hydraulic components for excavators. We will tear down and inspect your part with no obligation.
Established in 1978, Gator Pump manufactures high volume pumps for irrigation, flood control, liquid waste pumping and many other applications. Steel fabricated hydraulic pumps are offered in several different sizes and configurations including vertical pumps, floating pumps and trailer pumps as well as custom pumps operated on electric, diesel or hydraulics to suit clients" needs. Call us today!
We provide a number of different styles of air driven high pressure hydraulic pumps ranging from 100 PSI to 60,000 PSI. Here at High Pressure Technologies, LLC we take customer satisfaction very seriously which is why we can customize our products to match your requirements. It is our goal to exceed your expectations. Please visit our website or give us a call today to learn more information!
We started developing hydraulic drive submersible pumps in 1977. We can provide you with a hydraulic pump, hydraulic gear pump and hydraulic power unit to match. If a standard system doesn"t meet your needs, we can custom design one for you. We make our models in a variety of materials.
Since our beginning in 1947, Hydraulic Supply Company (HSC) has been dedicated to fulfilling customers’ needs. We are a full service distributor of fluid power products and services. We carry a selection of over 20,000 hydraulic, pneumatic and industrial products in stock from the most recognized brands in the industry. Our goal is to provide customers with a large selection of hydraulic, pneumatic and industrial products with the best professional services, right when you need them.
Made-to-order & made-to-last custom hydraulic pumps faster than you can expect from other companies. The widest selection of hydraulic gear pumps & piston pumps, plus stock replacement pumps ready for immediate shipment. Brands: Webster, Danfoss, Barnes, Haldex, Cessna, Eaton, Vickers, etc. Hydraulic.Net’s specialization is in short run special application gear pumps with little tooling expense.
Hydraulics International, Inc. (HII), headquartered in Chatsworth, California, U.S.A., is a leading manufacturer and supplier of integrated products, services and support to military forces, aviation and commercial industries, government agencies and prime contractors worldwide. Focused on defense and commercial technology, HII develops manufactures and supports a broad range of products and systems for over a hundred industries as well as mission critical and military sustainment requirements worldwide. HII is also recognized as a leading manufacturer and supplier of air, electric, hydraulic, & manual driven high-pressure products to Automotive, Airline & Aerospace, Cannabis, CNG, Defense, Fire-Health & Safety, Fluid Power, Fuel Cell Hydrogen, General Manufacturing, Laboratory, University & Research, Mining, Oil & Gas, Paintball, Plastics, Power & Energy, Recreational Sports Diving, Electronics and other industries. We produce 85% of our products internally, thus eliminating our dependency upon outside sources for quality, reliability, and expediency. Because of our self-sufficiency, we are able to maintain key competitive advantages that include faster response to engineering and design problems, and