variable displacement hydraulic pump animation pricelist

The displacement of a pump is defined by the volume of fluid that the gears, vanes or pistons will pump in one rotation. If a pump has a capacity of 30 cm3, it should treat 30 ml of fluid in one rotation.

In axial piston variable pumps, the flow is proportional to the drive speed and the displacement. The flow can be steplessly changed by adjusting the swivel angle. Axial piston variable ...

... axial piston pump type V60N is designed for open circuits in mobile hydraulics and operate according to the swash plate principle. They are available with the option of a thru-shaft for operating additional ...

Variable displacement axial piston pumps operate according to the bent axis principle. They adjust the geometric output volume from maximum to zero. As a result they vary the flow rate ...

... piston pump type V30D is designed for open circuits in industrial hydraulics and operate according to the swash plate principle. They are available with the option of a thru-shaft for operating additional ...

... circuit axial piston pumps are used as hydrostatic transmission components in self-propelled machines and for rotary drives in both fixed and mobile equipment of all kinds.

Axial piston twin flow pump. With a very high performance in all job conditions. Due to its twin flow configuration this pump allows a great variety of solutions in different job applications.

Air hydraulic pump, double pneumatic motor, double effect, foot operated with lock-up function, lever distributor valve (4/3), 10L tank, oil flow 8.5 / 0.26 l / min

... customer system options for mechanical, hydraulic and electric input solutions are available. Further special regulating features like torque control and pressure cut-off are also available. The reliable ...

... needs of truck hydraulics, the TXV variable displacement pumps with LS (Load Sensing) control allow flow regulation to suit the application requirements. The pump ...

... rev. displacements, these pumps are designed to operate in both directions of rotation (clockwise or counter-clockwise). Only one reference regardless of direction of rotation. The TXV indexable pumps ...

... PVG is a variable-displacement axial-piston pump designed to take on your most demanding applications. It offers high-pressure, superior performance in a compact design ...

Variable displacement pumps in closed loop; 3 basic design units and 8 max. displacement sizes of 14, 18, 21, 28, 35, 46, 56, 64 cc/rev; various control options; max. ...

Parker P2/P3 High Pressure Axial Piston Pumps are variable displacement, swashplate piston pumps designed for operation in open circuit, mobile hydraulic ...

... Series pump offers variable displacement axial piston pumps for open-circuit applications. Featuring a compact footprint and continuous operating pressure ...

Mechanical pumps serve in a wide range of applications such as pumping water from wells, aquarium filtering, pond filtering and aeration, in the car industry for water-cooling and fuel injection, in the energy industry for pumping oil and natural gas or for operating cooling towers and other components of heating, ventilation and air conditioning systems. In the medical industry, pumps are used for biochemical processes in developing and manufacturing medicine, and as artificial replacements for body parts, in particular the artificial heart and penile prosthesis.

When a pump contains two or more pump mechanisms with fluid being directed to flow through them in series, it is called a multi-stage pump. Terms such as two-stage or double-stage may be used to specifically describe the number of stages. A pump that does not fit this description is simply a single-stage pump in contrast.

In biology, many different types of chemical and biomechanical pumps have evolved; biomimicry is sometimes used in developing new types of mechanical pumps.

Pumps can be classified by their method of displacement into positive-displacement pumps, impulse pumps, velocity pumps, gravity pumps, steam pumps and valveless pumps. There are three basic types of pumps: positive-displacement, centrifugal and axial-flow pumps. In centrifugal pumps the direction of flow of the fluid changes by ninety degrees as it flows over an impeller, while in axial flow pumps the direction of flow is unchanged.

Some positive-displacement pumps use an expanding cavity on the suction side and a decreasing cavity on the discharge side. Liquid flows into the pump as the cavity on the suction side expands and the liquid flows out of the discharge as the cavity collapses. The volume is constant through each cycle of operation.

Positive-displacement pumps, unlike centrifugal, can theoretically produce the same flow at a given speed (rpm) no matter what the discharge pressure. Thus, positive-displacement pumps are constant flow machines. However, a slight increase in internal leakage as the pressure increases prevents a truly constant flow rate.

A positive-displacement pump must not operate against a closed valve on the discharge side of the pump, because it has no shutoff head like centrifugal pumps. A positive-displacement pump operating against a closed discharge valve continues to produce flow and the pressure in the discharge line increases until the line bursts, the pump is severely damaged, or both.

A relief or safety valve on the discharge side of the positive-displacement pump is therefore necessary. The relief valve can be internal or external. The pump manufacturer normally has the option to supply internal relief or safety valves. The internal valve is usually used only as a safety precaution. An external relief valve in the discharge line, with a return line back to the suction line or supply tank provides increased safety.

Rotary-type positive displacement: internal or external gear pump, screw pump, lobe pump, shuttle block, flexible vane or sliding vane, circumferential piston, flexible impeller, helical twisted roots (e.g. the Wendelkolben pump) or liquid-ring pumps

Drawbacks: The nature of the pump requires very close clearances between the rotating pump and the outer edge, making it rotate at a slow, steady speed. If rotary pumps are operated at high speeds, the fluids cause erosion, which eventually causes enlarged clearances that liquid can pass through, which reduces efficiency.

Hollow disk pumps (also known as eccentric disc pumps or Hollow rotary disc pumps), similar to scroll compressors, these have a cylindrical rotor encased in a circular housing. As the rotor orbits and rotates to some degree, it traps fluid between the rotor and the casing, drawing the fluid through the pump. It is used for highly viscous fluids like petroleum-derived products, and it can also support high pressures of up to 290 psi.

Vibratory pumps or vibration pumps are similar to linear compressors, having the same operating principle. They work by using a spring-loaded piston with an electromagnet connected to AC current through a diode. The spring-loaded piston is the only moving part, and it is placed in the center of the electromagnet. During the positive cycle of the AC current, the diode allows energy to pass through the electromagnet, generating a magnetic field that moves the piston backwards, compressing the spring, and generating suction. During the negative cycle of the AC current, the diode blocks current flow to the electromagnet, letting the spring uncompress, moving the piston forward, and pumping the fluid and generating pressure, like a reciprocating pump. Due to its low cost, it is widely used in inexpensive espresso machines. However, vibratory pumps cannot be operated for more than one minute, as they generate large amounts of heat. Linear compressors do not have this problem, as they can be cooled by the working fluid (which is often a refrigerant).

Reciprocating pumps move the fluid using one or more oscillating pistons, plungers, or membranes (diaphragms), while valves restrict fluid motion to the desired direction. In order for suction to take place, the pump must first pull the plunger in an outward motion to decrease pressure in the chamber. Once the plunger pushes back, it will increase the chamber pressure and the inward pressure of the plunger will then open the discharge valve and release the fluid into the delivery pipe at constant flow rate and increased pressure.

Pumps in this category range from simplex, with one cylinder, to in some cases quad (four) cylinders, or more. Many reciprocating-type pumps are duplex (two) or triplex (three) cylinder. They can be either single-acting with suction during one direction of piston motion and discharge on the other, or double-acting with suction and discharge in both directions. The pumps can be powered manually, by air or steam, or by a belt driven by an engine. This type of pump was used extensively in the 19th century—in the early days of steam propulsion—as boiler feed water pumps. Now reciprocating pumps typically pump highly viscous fluids like concrete and heavy oils, and serve in special applications that demand low flow rates against high resistance. Reciprocating hand pumps were widely used to pump water from wells. Common bicycle pumps and foot pumps for inflation use reciprocating action.

These positive-displacement pumps have an expanding cavity on the suction side and a decreasing cavity on the discharge side. Liquid flows into the pumps as the cavity on the suction side expands and the liquid flows out of the discharge as the cavity collapses. The volume is constant given each cycle of operation and the pump"s volumetric efficiency can be achieved through routine maintenance and inspection of its valves.

This is the simplest form of rotary positive-displacement pumps. It consists of two meshed gears that rotate in a closely fitted casing. The tooth spaces trap fluid and force it around the outer periphery. The fluid does not travel back on the meshed part, because the teeth mesh closely in the center. Gear pumps see wide use in car engine oil pumps and in various hydraulic power packs.

A screw pump is a more complicated type of rotary pump that uses two or three screws with opposing thread — e.g., one screw turns clockwise and the other counterclockwise. The screws are mounted on parallel shafts that have gears that mesh so the shafts turn together and everything stays in place. The screws turn on the shafts and drive fluid through the pump. As with other forms of rotary pumps, the clearance between moving parts and the pump"s casing is minimal.

Widely used for pumping difficult materials, such as sewage sludge contaminated with large particles, a progressing cavity pump consists of a helical rotor, about ten times as long as its width. This can be visualized as a central core of diameter x with, typically, a curved spiral wound around of thickness half x, though in reality it is manufactured in a single casting. This shaft fits inside a heavy-duty rubber sleeve, of wall thickness also typically x. As the shaft rotates, the rotor gradually forces fluid up the rubber sleeve. Such pumps can develop very high pressure at low volumes.

Named after the Roots brothers who invented it, this lobe pump displaces the fluid trapped between two long helical rotors, each fitted into the other when perpendicular at 90°, rotating inside a triangular shaped sealing line configuration, both at the point of suction and at the point of discharge. This design produces a continuous flow with equal volume and no vortex. It can work at low pulsation rates, and offers gentle performance that some applications require.

A peristaltic pump is a type of positive-displacement pump. It contains fluid within a flexible tube fitted inside a circular pump casing (though linear peristaltic pumps have been made). A number of rollers, shoes, or wipers attached to a rotor compresses the flexible tube. As the rotor turns, the part of the tube under compression closes (or occludes), forcing the fluid through the tube. Additionally, when the tube opens to its natural state after the passing of the cam it draws (restitution) fluid into the pump. This process is called peristalsis and is used in many biological systems such as the gastrointestinal tract.

Efficiency and common problems: With only one cylinder in plunger pumps, the fluid flow varies between maximum flow when the plunger moves through the middle positions, and zero flow when the plunger is at the end positions. A lot of energy is wasted when the fluid is accelerated in the piping system. Vibration and

Triplex plunger pumps use three plungers, which reduces the pulsation of single reciprocating plunger pumps. Adding a pulsation dampener on the pump outlet can further smooth the pump ripple, or ripple graph of a pump transducer. The dynamic relationship of the high-pressure fluid and plunger generally requires high-quality plunger seals. Plunger pumps with a larger number of plungers have the benefit of increased flow, or smoother flow without a pulsation damper. The increase in moving parts and crankshaft load is one drawback.

Car washes often use these triplex-style plunger pumps (perhaps without pulsation dampers). In 1968, William Bruggeman reduced the size of the triplex pump and increased the lifespan so that car washes could use equipment with smaller footprints. Durable high-pressure seals, low-pressure seals and oil seals, hardened crankshafts, hardened connecting rods, thick ceramic plungers and heavier duty ball and roller bearings improve reliability in triplex pumps. Triplex pumps now are in a myriad of markets across the world.

Triplex pumps with shorter lifetimes are commonplace to the home user. A person who uses a home pressure washer for 10 hours a year may be satisfied with a pump that lasts 100 hours between rebuilds. Industrial-grade or continuous duty triplex pumps on the other end of the quality spectrum may run for as much as 2,080 hours a year.

The oil and gas drilling industry uses massive semi trailer-transported triplex pumps called mud pumps to pump drilling mud, which cools the drill bit and carries the cuttings back to the surface.

One modern application of positive-displacement pumps is compressed-air-powered double-diaphragm pumps. Run on compressed air, these pumps are intrinsically safe by design, although all manufacturers offer ATEX certified models to comply with industry regulation. These pumps are relatively inexpensive and can perform a wide variety of duties, from pumping water out of bunds to pumping hydrochloric acid from secure storage (dependent on how the pump is manufactured – elastomers / body construction). These double-diaphragm pumps can handle viscous fluids and abrasive materials with a gentle pumping process ideal for transporting shear-sensitive media.

Devised in China as chain pumps over 1000 years ago, these pumps can be made from very simple materials: A rope, a wheel and a pipe are sufficient to make a simple rope pump. Rope pump efficiency has been studied by grassroots organizations and the techniques for making and running them have been continuously improved.

Impulse pumps use pressure created by gas (usually air). In some impulse pumps the gas trapped in the liquid (usually water), is released and accumulated somewhere in the pump, creating a pressure that can push part of the liquid upwards.

Instead of a gas accumulation and releasing cycle, the pressure can be created by burning of hydrocarbons. Such combustion driven pumps directly transmit the impulse from a combustion event through the actuation membrane to the pump fluid. In order to allow this direct transmission, the pump needs to be almost entirely made of an elastomer (e.g. silicone rubber). Hence, the combustion causes the membrane to expand and thereby pumps the fluid out of the adjacent pumping chamber. The first combustion-driven soft pump was developed by ETH Zurich.

It takes in water at relatively low pressure and high flow-rate and outputs water at a higher hydraulic-head and lower flow-rate. The device uses the water hammer effect to develop pressure that lifts a portion of the input water that powers the pump to a point higher than where the water started.

The hydraulic ram is sometimes used in remote areas, where there is both a source of low-head hydropower, and a need for pumping water to a destination higher in elevation than the source. In this situation, the ram is often useful, since it requires no outside source of power other than the kinetic energy of flowing water.

Rotodynamic pumps (or dynamic pumps) are a type of velocity pump in which kinetic energy is added to the fluid by increasing the flow velocity. This increase in energy is converted to a gain in potential energy (pressure) when the velocity is reduced prior to or as the flow exits the pump into the discharge pipe. This conversion of kinetic energy to pressure is explained by the

A practical difference between dynamic and positive-displacement pumps is how they operate under closed valve conditions. Positive-displacement pumps physically displace fluid, so closing a valve downstream of a positive-displacement pump produces a continual pressure build up that can cause mechanical failure of pipeline or pump. Dynamic pumps differ in that they can be safely operated under closed valve conditions (for short periods of time).

Such a pump is also referred to as a centrifugal pump. The fluid enters along the axis or center, is accelerated by the impeller and exits at right angles to the shaft (radially); an example is the centrifugal fan, which is commonly used to implement a vacuum cleaner. Another type of radial-flow pump is a vortex pump. The liquid in them moves in tangential direction around the working wheel. The conversion from the mechanical energy of motor into the potential energy of flow comes by means of multiple whirls, which are excited by the impeller in the working channel of the pump. Generally, a radial-flow pump operates at higher pressures and lower flow rates than an axial- or a mixed-flow pump.

These are also referred to as All fluid pumps. The fluid is pushed outward or inward to move fluid axially. They operate at much lower pressures and higher flow rates than radial-flow (centrifugal) pumps. Axial-flow pumps cannot be run up to speed without special precaution. If at a low flow rate, the total head rise and high torque associated with this pipe would mean that the starting torque would have to become a function of acceleration for the whole mass of liquid in the pipe system. If there is a large amount of fluid in the system, accelerate the pump slowly.

Mixed-flow pumps function as a compromise between radial and axial-flow pumps. The fluid experiences both radial acceleration and lift and exits the impeller somewhere between 0 and 90 degrees from the axial direction. As a consequence mixed-flow pumps operate at higher pressures than axial-flow pumps while delivering higher discharges than radial-flow pumps. The exit angle of the flow dictates the pressure head-discharge characteristic in relation to radial and mixed-flow.

Regenerative turbine pump rotor and housing, 1⁄3 horsepower (0.25 kW). 85 millimetres (3.3 in) diameter impeller rotates counter-clockwise. Left: inlet, right: outlet. .4 millimetres (0.016 in) thick vanes on 4 millimetres (0.16 in) centers

Also known as drag, friction, peripheral, traction, turbulence, or vortex pumps, regenerative turbine pumps are class of rotodynamic pump that operates at high head pressures, typically 4–20 bars (4.1–20.4 kgf/cm2; 58–290 psi).

The pump has an impeller with a number of vanes or paddles which spins in a cavity. The suction port and pressure ports are located at the perimeter of the cavity and are isolated by a barrier called a stripper, which allows only the tip channel (fluid between the blades) to recirculate, and forces any fluid in the side channel (fluid in the cavity outside of the blades) through the pressure port. In a regenerative turbine pump, as fluid spirals repeatedly from a vane into the side channel and back to the next vane, kinetic energy is imparted to the periphery,

As regenerative turbine pumps cannot become vapor locked, they are commonly applied to volatile, hot, or cryogenic fluid transport. However, as tolerances are typically tight, they are vulnerable to solids or particles causing jamming or rapid wear. Efficiency is typically low, and pressure and power consumption typically decrease with flow. Additionally, pumping direction can be reversed by reversing direction of spin.

Steam pumps have been for a long time mainly of historical interest. They include any type of pump powered by a steam engine and also pistonless pumps such as Thomas Savery"s or the Pulsometer steam pump.

Recently there has been a resurgence of interest in low power solar steam pumps for use in smallholder irrigation in developing countries. Previously small steam engines have not been viable because of escalating inefficiencies as vapour engines decrease in size. However the use of modern engineering materials coupled with alternative engine configurations has meant that these types of system are now a cost-effective opportunity.

Valveless pumping assists in fluid transport in various biomedical and engineering systems. In a valveless pumping system, no valves (or physical occlusions) are present to regulate the flow direction. The fluid pumping efficiency of a valveless system, however, is not necessarily lower than that having valves. In fact, many fluid-dynamical systems in nature and engineering more or less rely upon valveless pumping to transport the working fluids therein. For instance, blood circulation in the cardiovascular system is maintained to some extent even when the heart"s valves fail. Meanwhile, the embryonic vertebrate heart begins pumping blood long before the development of discernible chambers and valves. Similar to blood circulation in one direction, bird respiratory systems pump air in one direction in rigid lungs, but without any physiological valve. In microfluidics, valveless impedance pumps have been fabricated, and are expected to be particularly suitable for handling sensitive biofluids. Ink jet printers operating on the piezoelectric transducer principle also use valveless pumping. The pump chamber is emptied through the printing jet due to reduced flow impedance in that direction and refilled by capillary action.

Examining pump repair records and mean time between failures (MTBF) is of great importance to responsible and conscientious pump users. In view of that fact, the preface to the 2006 Pump User"s Handbook alludes to "pump failure" statistics. For the sake of convenience, these failure statistics often are translated into MTBF (in this case, installed life before failure).

In early 2005, Gordon Buck, John Crane Inc.’s chief engineer for field operations in Baton Rouge, Louisiana, examined the repair records for a number of refinery and chemical plants to obtain meaningful reliability data for centrifugal pumps. A total of 15 operating plants having nearly 15,000 pumps were included in the survey. The smallest of these plants had about 100 pumps; several plants had over 2000. All facilities were located in the United States. In addition, considered as "new", others as "renewed" and still others as "established". Many of these plants—but not all—had an alliance arrangement with John Crane. In some cases, the alliance contract included having a John Crane Inc. technician or engineer on-site to coordinate various aspects of the program.

Not all plants are refineries, however, and different results occur elsewhere. In chemical plants, pumps have historically been "throw-away" items as chemical attack limits life. Things have improved in recent years, but the somewhat restricted space available in "old" DIN and ASME-standardized stuffing boxes places limits on the type of seal that fits. Unless the pump user upgrades the seal chamber, the pump only accommodates more compact and simple versions. Without this upgrading, lifetimes in chemical installations are generally around 50 to 60 percent of the refinery values.

Unscheduled maintenance is often one of the most significant costs of ownership, and failures of mechanical seals and bearings are among the major causes. Keep in mind the potential value of selecting pumps that cost more initially, but last much longer between repairs. The MTBF of a better pump may be one to four years longer than that of its non-upgraded counterpart. Consider that published average values of avoided pump failures range from US$2600 to US$12,000. This does not include lost opportunity costs. One pump fire occurs per 1000 failures. Having fewer pump failures means having fewer destructive pump fires.

As has been noted, a typical pump failure, based on actual year 2002 reports, costs US$5,000 on average. This includes costs for material, parts, labor and overhead. Extending a pump"s MTBF from 12 to 18 months would save US$1,667 per year — which might be greater than the cost to upgrade the centrifugal pump"s reliability.

Pumps are used throughout society for a variety of purposes. Early applications includes the use of the windmill or watermill to pump water. Today, the pump is used for irrigation, water supply, gasoline supply, air conditioning systems, refrigeration (usually called a compressor), chemical movement, sewage movement, flood control, marine services, etc.

Because of the wide variety of applications, pumps have a plethora of shapes and sizes: from very large to very small, from handling gas to handling liquid, from high pressure to low pressure, and from high volume to low volume.

Typically, a liquid pump can"t simply draw air. The feed line of the pump and the internal body surrounding the pumping mechanism must first be filled with the liquid that requires pumping: An operator must introduce liquid into the system to initiate the pumping. This is called priming the pump. Loss of prime is usually due to ingestion of air into the pump. The clearances and displacement ratios in pumps for liquids, whether thin or more viscous, usually cannot displace air due to its compressibility. This is the case with most velocity (rotodynamic) pumps — for example, centrifugal pumps. For such pumps, the position of the pump should always be lower than the suction point, if not the pump should be manually filled with liquid or a secondary pump should be used until all air is removed from the suction line and the pump casing.

Positive–displacement pumps, however, tend to have sufficiently tight sealing between the moving parts and the casing or housing of the pump that they can be described as self-priming. Such pumps can also serve as priming pumps, so-called when they are used to fulfill that need for other pumps in lieu of action taken by a human operator.

One sort of pump once common worldwide was a hand-powered water pump, or "pitcher pump". It was commonly installed over community water wells in the days before piped water supplies.

In parts of the British Isles, it was often called the parish pump. Though such community pumps are no longer common, people still used the expression parish pump to describe a place or forum where matters of local interest are discussed.

Because water from pitcher pumps is drawn directly from the soil, it is more prone to contamination. If such water is not filtered and purified, consumption of it might lead to gastrointestinal or other water-borne diseases. A notorious case is the 1854 Broad Street cholera outbreak. At the time it was not known how cholera was transmitted, but physician John Snow suspected contaminated water and had the handle of the public pump he suspected removed; the outbreak then subsided.

Modern hand-operated community pumps are considered the most sustainable low-cost option for safe water supply in resource-poor settings, often in rural areas in developing countries. A hand pump opens access to deeper groundwater that is often not polluted and also improves the safety of a well by protecting the water source from contaminated buckets. Pumps such as the Afridev pump are designed to be cheap to build and install, and easy to maintain with simple parts. However, scarcity of spare parts for these type of pumps in some regions of Africa has diminished their utility for these areas.

Multiphase pumping applications, also referred to as tri-phase, have grown due to increased oil drilling activity. In addition, the economics of multiphase production is attractive to upstream operations as it leads to simpler, smaller in-field installations, reduced equipment costs and improved production rates. In essence, the multiphase pump can accommodate all fluid stream properties with one piece of equipment, which has a smaller footprint. Often, two smaller multiphase pumps are installed in series rather than having just one massive pump.

A rotodynamic pump with one single shaft that requires two mechanical seals, this pump uses an open-type axial impeller. It is often called a Poseidon pump, and can be described as a cross between an axial compressor and a centrifugal pump.

The twin-screw pump is constructed of two inter-meshing screws that move the pumped fluid. Twin screw pumps are often used when pumping conditions contain high gas volume fractions and fluctuating inlet conditions. Four mechanical seals are required to seal the two shafts.

These pumps are basically multistage centrifugal pumps and are widely used in oil well applications as a method for artificial lift. These pumps are usually specified when the pumped fluid is mainly liquid.

A buffer tank is often installed upstream of the pump suction nozzle in case of a slug flow. The buffer tank breaks the energy of the liquid slug, smooths any fluctuations in the incoming flow and acts as a sand trap.

As the name indicates, multiphase pumps and their mechanical seals can encounter a large variation in service conditions such as changing process fluid composition, temperature variations, high and low operating pressures and exposure to abrasive/erosive media. The challenge is selecting the appropriate mechanical seal arrangement and support system to ensure maximized seal life and its overall effectiveness.

Pumps are commonly rated by horsepower, volumetric flow rate, outlet pressure in metres (or feet) of head, inlet suction in suction feet (or metres) of head.

From an initial design point of view, engineers often use a quantity termed the specific speed to identify the most suitable pump type for a particular combination of flow rate and head.

The power imparted into a fluid increases the energy of the fluid per unit volume. Thus the power relationship is between the conversion of the mechanical energy of the pump mechanism and the fluid elements within the pump. In general, this is governed by a series of simultaneous differential equations, known as the Navier–Stokes equations. However a more simple equation relating only the different energies in the fluid, known as Bernoulli"s equation can be used. Hence the power, P, required by the pump:

where Δp is the change in total pressure between the inlet and outlet (in Pa), and Q, the volume flow-rate of the fluid is given in m3/s. The total pressure may have gravitational, static pressure and kinetic energy components; i.e. energy is distributed between change in the fluid"s gravitational potential energy (going up or down hill), change in velocity, or change in static pressure. η is the pump efficiency, and may be given by the manufacturer"s information, such as in the form of a pump curve, and is typically derived from either fluid dynamics simulation (i.e. solutions to the Navier–Stokes for the particular pump geometry), or by testing. The efficiency of the pump depends upon the pump"s configuration and operating conditions (such as rotational speed, fluid density and viscosity etc.)

For a typical "pumping" configuration, the work is imparted on the fluid, and is thus positive. For the fluid imparting the work on the pump (i.e. a turbine), the work is negative. Power required to drive the pump is determined by dividing the output power by the pump efficiency. Furthermore, this definition encompasses pumps with no moving parts, such as a siphon.

Pump efficiency is defined as the ratio of the power imparted on the fluid by the pump in relation to the power supplied to drive the pump. Its value is not fixed for a given pump, efficiency is a function of the discharge and therefore also operating head. For centrifugal pumps, the efficiency tends to increase with flow rate up to a point midway through the operating range (peak efficiency or Best Efficiency Point (BEP) ) and then declines as flow rates rise further. Pump performance data such as this is usually supplied by the manufacturer before pump selection. Pump efficiencies tend to decline over time due to wear (e.g. increasing clearances as impellers reduce in size).

When a system includes a centrifugal pump, an important design issue is matching the head loss-flow characteristic with the pump so that it operates at or close to the point of its maximum efficiency.

Most large pumps have a minimum flow requirement below which the pump may be damaged by overheating, impeller wear, vibration, seal failure, drive shaft damage or poor performance.

The simplest minimum flow system is a pipe running from the pump discharge line back to the suction line. This line is fitted with an orifice plate sized to allow the pump minimum flow to pass.

A more sophisticated, but more costly, system (see diagram) comprises a flow measuring device (FE) in the pump discharge which provides a signal into a flow controller (FIC) which actuates a flow control valve (FCV) in the recycle line. If the measured flow exceeds the minimum flow then the FCV is closed. If the measured flow falls below the minimum flow the FCV opens to maintain the minimum flowrate.

As the fluids are recycled the kinetic energy of the pump increases the temperature of the fluid. For many pumps this added heat energy is dissipated through the pipework. However, for large industrial pumps, such as oil pipeline pumps, a recycle cooler is provided in the recycle line to cool the fluids to the normal suction temperature.oil refinery, oil terminal, or offshore installation.

Engineering Sciences Data Unit (2007). "Radial, mixed and axial flow pumps. Introduction" (PDF). Archived from the original (PDF) on 2014-03-08. Retrieved 2017-08-18.

Tanzania water Archived 2012-03-31 at the Wayback Machine blog – example of grassroots researcher telling about his study and work with the rope pump in Africa.

C.M. Schumacher, M. Loepfe, R. Fuhrer, R.N. Grass, and W.J. Stark, "3D printed lost-wax casted soft silicone monoblocks enable heart-inspired pumping by internal combustion," RSC Advances, Vol. 4, pp. 16039–16042, 2014.

"Radial, mixed and axial flow pumps" (PDF). Institution of Diploma Marine Engineers, Bangladesh. June 2003. Archived from the original (PDF) on 2014-03-08. Retrieved 2017-08-18.

Quail F, Scanlon T, Stickland M (2011-01-11). "Design optimisation of a regenerative pump using numerical and experimental techniques" (PDF). International Journal of Numerical Methods for Heat & Fluid Flow. 21: 95–111. doi:10.1108/09615531111095094. Retrieved 2021-07-21.

Rajmane, M. Satish; Kallurkar, S.P. (May 2015). "CFD Analysis of Domestic Centrifugal Pump for Performance Enhancement". International Research Journal of Engineering and Technology. 02 / #02. Retrieved 30 April 2021.

Wasser, Goodenberger, Jim and Bob (November 1993). "Extended Life, Zero Emissions Seal for Process Pumps". John Crane Technical Report. Routledge. TRP 28017.

Australian Pump Manufacturers" Association. Australian Pump Technical Handbook, 3rd edition. Canberra: Australian Pump Manufacturers" Association, 1987. ISBN 0-7316-7043-4.

Another variable displacement pump is the piston, which is a quick compressor and has a low-pressure pressure. The piston is tendential and is more affordable than the other one because hydraulic technology is more affordable than reciprocating pumps.

Variable displacement pumps vary in the number, types, and sizes. One variable displacement pumps vary in the number, one, and many others. A piston type is compressed, and it has a low-pressage capacity compared to other variable displacement pumps. The piston type is compressed and has a low-pressure capacity.

Many hydraulic pumps are variable displacement, such as piston hydraulic pumps, variable displacement hydraulic pumps, variable displacement pumps, and hydraulic piston pumps, variable displacement pumps have a number of pumps. Among various types of hydraulic displacement pumps, variable displacement pumps are one of the best.

Variable displacement hydraulic pumps can be found for many purposes. Whenalling hydraulic pumps, the variable displacement of the hydraulic pumps is one for a considerable period of time, and it saves time and effort by installing hydraulic piston pumps.

The number of components in any hydraulic power unit may vary depending on the complexity of the system. Normally, all these depend on the specific applications of the power unit.

I will make the entire discussion simple and easy to understand. This is because you need to evaluate every component before buying the hydraulic power unit.

In a hydraulic circuit, electric motors convert the electrical energy into a rotational force that drives the pump gear. You’ll learn more about pump gears in section 3.2 of this chapter.

The electrical DC motors convert direct current into a rotational mechanical energy. These motors use a direct power supply whose voltage may vary from DC12V, DC24V, DC48V or DC96V; depending on the design specification of the hydraulic power pack system.

These motors are common in most micro or mini hydraulic power packs. This is because the DC power supply is portable thus, a perfect choice for mobile of portable hydraulic equipment.

For large DC motors that are commonly found in large hydraulic systems, the electric motor manufacturers use electromagnet instead of permanent magnets.

The complexity of the design will depend on the type load the motor should drive. In the case of the hydraulic power packs, we have a hydraulic pump as the load.

In the recent past, a number of hydraulic power pack manufacturers have adopted the permanent magnet and brushless DC motors for most pump applications. The brushed wound field DC motors are still common in some hydraulic applications.

Quite a number of AC hydraulic power packs use induction motors. The most common types of induction motors are:Three phase induction AC motors – requires three power phases

A hydraulic pump is a device that converts the mechanical energy from the motor (rotary motion) into a hydraulic energy. The output shaft from the electric motor is coupled to the shaft of the hydraulic pump.

As the pump rotates, it creates a pressure difference between its inlet and outlet. This pressure difference helps the pump to draw hydraulic fluid from the tank.

It then pushes the hydraulic fluid through the tubes/pipes to the hydraulic cylinder parts or hydraulic motor. In this section, I will focus on the following types of hydraulic pumps:Gear pumps

As you’ll realize in sections 3.2.1, 3.2.2 and 3.2.3, this classification is based on the structural design of these pumps. In each category, I will:Explain the working principle of the pump

As the gears rotate, they create a suction effect at the pump’s inlet and the fluid is drawn into the pump chamber. The rotation directs the hydraulic fluid between the teeth of the gears and the walls of the pump and finally to the output.

In most cases, it is one shaft of the gear that is coupled to the electric motor. Thus, the movement of the second gear (driven gear) occurs as the other gear (driving gear) engages it when the pump is operating.

The herringbone and helical gears in these hydraulic pumps offer a smooth flow than spur gears. The flow rate of these gears is determined by a number of features such as:Size of volume between the gear teeth

These hydraulic pumps have an externally-cut teeth that are contained in and meshed another gear that has an internally-cut teeth. Liquid is drawn when the gears come out of mesh and is discharged when the gears mesh together.

These pumps use their contracting and expanding cavities to move hydraulic fluids from the cylinder to the tubes. This is possible with the help of an electric motor that creates motion, pistons and check valves.

Hydraulic pistons undergo a reciprocating motion (moving up and down or back and forth), thereby building a pressure that forces the fluid through the tubes.

It has a cylindrical block with pistons that move in the direction of its centerline. They have simple designs and guarantee reliable operation.Radial Piston Pump

Its pistons are attached to cylindrical block, forming a wheel like structure. The rotation of the cylindrical block causes a back and forth motion within the pump.

This fluid flows into the hydraulic vane pump chambers. The volume of the vane chambers at the inlet sections is larger than that at the outlet section of the pump.

These pumps can be classified further as either unbalanced or balanced vane pumps. Most opt for the balanced vane pumps because they have better speed ratings, high pressure and increased bearing lifetime.Variable displacement vane pumps

Like other hydraulic pumps, the vane pumps may not be suitable for certain pumping applications. Here are the main advantages and disadvantages of these pumps.

Type of materials for these main sections:Shaft seal – Component mechanical seals, industry-standard cartridge mechanical seals, and magnetic-driven pumps.

With these two main components of the hydraulic power pack (electric motor and pump), your systems should draw the hydraulic fluid, ready to supply it to the circuit.

A hydraulic manifold helps to regulate the fluid flow, pressure and flow direction in hydraulic systems. It acts a junction between the hydraulic pump and hydraulic actuators.

The hydraulic manifold design may vary depending on the types and number of control components. With the help of various hydraulic manifold valves, you can easily monitor and control the fluid flow.

As you’ll realize later in this section, these hydraulic manifold blocks mainly vary depending on how hydraulic valves are interconnected to each other.

The hydraulic central manifold has several multiple options you can use for integral solenoid, mechanical operated hydraulic valves and an interface for custom designed valves.

For more complex and flexible functionalities, you can use the hydraulic stacked manifold. This helps to combine multiple functions into one assembly such as reducing the possibility of pressure drop.

This is actually the main reason why you should consider a stacked manifold block as an extra section of the hydraulic center block. You can use it when the space in the central manifold cannot hold more valves or large size cartridge valves.

Target has delivered thousands hydraulic power units for different applications around the world. These include a series of standard hydraulic manifolds that are commonly used in most hydraulic power packs.

At times, the standard hydraulic power packs may not meet the specific requirements of your applications. In such cases, you should opt for customized hydraulic manifold blocks that meet your specific requirements

Apart from the hydraulic manifold blocks, I need to introduce you to the actual components that control the hydraulic fluid. This is the hydraulic valves.

Valves are devices that control the flow of fluids in hydraulic systems. They regulate flow by cutting-off, diverting, providing an overflow relief and preventing reverse flow of the hydraulic fluid, among other functions.

There are very many hydraulics valves available in the market. However, for the scope of this eBook, I will focus on the following:Hydraulic check valves

As you can see, there are many types of hydraulic cartridge valves available in the market. These valves are suitable for high flow rates and leak free control systems such as hydraulic power packs.

A hydraulic check valve allows fluid to flow through it in one direction, i.e. it prevents a reverse flow. For this reason, it is also referred to as one-way valve or non-return valve.

Since the check valves provide unidirectional flow, thereby providing a sealing against the reverse flow, it is advisable that you install them on the outlet side of the hydraulic pump. Below, is an image showing how a hydraulic check ball valve functions:

In hydraulic power pack circuits, you’ll mount the internal check valve in the block, while the external check valve on mounting hole found on the surface of the valve block.

At times, hydraulic power pack manufacturing companies may include a pilot operated check valve. You can control these valves using fluids from other valves.

A hydraulic pilot-operated check valve is unique in the sense that; they allow hydraulic fluid to flow in one direction, but, you can still disable them using a pilot pressure.

In hydraulic circuits, relief valves protect the downstream circuits from over pressurization. They are a good example of a safety valve and you may also refer to them as pressure relief valves (PRV).

During the period of work cycles, these pilot operated relief valves unload the pump at low pressure. Another important classification criteria is the type of material.

A number of adjustable hydraulic pressure relief valves are manufactured from zinc plated carbon steel bodies. They have hardened stainless steel sealing components.

You’ll find that when the pressure is reduced within 25% of the set point, the valve will automatically reseal. Below is the actual image of a hydraulic relief valve:

Below are seven crucial parameters you need to consider when buying a pressure valve:Pressure rating; it should be compatible with your hydraulic power pack system pressure.

In most applications, a hydraulic release valve also means a 2 way 2 position hydraulic cartridge solenoid valve. Solenoid valves are electromechanical operated valves.

Such valves have a fast and a safe switching mechanism. They are also: reliable, durable, compact in design and offer low control power. Below are examples of hydraulic release valves:

Since these directional control valves have a solenoid, their control mechanism depends on electrical energy. In most cases, you can refer to them as a variable force solenoid.

It’s the electric current that makes it a two-way valve. Where, it will allow the hydraulic fluid to return to the tank, thereby, releasing the load of the cylinder.

Owing to the varying circuit designs of directional control valves, you’ll find quite a number of hydraulic control valves and valve block mounting dimensions.

Normally, you can adjust hydraulic solenoid valve depending on the type of control mechanism of a specific application. Moreover, the complexity of a directional control valve will also depend on the specific hydraulic system you intend to control.

In most hydraulic circuits, you can install them near delicate gauges that may get damaged in case of a sudden pressure surge. Also, you can use these throttle valves in the pipes returning oil back to the tank.

Needle valves can handle a wide range of pressures. Depending on the nature of the hydraulic fluid system, a needle valve can handle the pressures that range from 5,000 to 6,000 psi.

Some of the most common materials include carbon steel, stainless steel or brass. Each material has unique physical and chemical properties making them suitable for specific hydraulic applications.

The complexity of the design will depend on the specific application of the directional valve in a hydraulic control circuit. In hydraulic circuits, the directional control valve symbol is:

Modular valves provide a wide range of mounting options in hydraulic circuits. They have a number of mounting holes, valves and loops compared to cartridge valves.

You can fit them in any system to fulfill the specific hydraulic circuit requirements. At the moment, there is a wide range of modular valves available in the market such as pilot operated check valves, flow control valves, pressure reducing valves and counterbalance valves.

The hydraulic flow valves are available in a wide range of configurations and designs, depending on the functional purposes of each valve. A good example is a modular flow control valve with a directional control valve and a sub plate.

As you can see, there are very many types of modular valves. Therefore, you need to review the manufacturer’s data sheet to choose a modular design that best suits your hydraulic system.

Throughout this section, I believe you have noted that there are very many types of hydraulic valves. Always choose one that best suits your hydraulic power pack.

Remember, with an appropriate valve, you can have full control of the fluid flowing through the hydraulic pipes. Now, let’s discuss the next component of a hydraulic power pack.

A hydraulic tank is a container that holds the fluid that you’ll supply to the system to do the work. At times, you may refer to it as a hydraulic reservoir.

Hydraulic oil tanks for power pack units come in a wide range of shapes, sizes and materials. For the scope of this eBook, I will focus on the following:Hydraulic plastic tanks

Quite a number of hydraulic plastic tanks are made from polypropylene (PP). This is a special oil tank material that is resistant to corrosion, low temperature, high temperature, acid-alkaline solutions and solar radiation.

Most manufacturers use an injection molding technique that results in a light weight and strong hydraulic fluid tank. The tank can withstand high pressure and resistant to diverse weather conditions.

The size may vary depending on both design and size of the hydraulic power pack. The volume of the tank should be large enough to allow for all hydraulic fluids in the pipes to drain in the tank.

Therefore, you’ll find that the hydraulic fuel tank size may vary depending on the hydraulic equipment such as hydraulic stacker, hydraulic lifting equipment, hydraulic dock ramp, hydraulic scissor lift, etc.

Like the plastic hydraulic reservoir tanks, the hydraulic steel tanks are available in a wide range of sizes and designs. Unfortunately, for these hydraulic power pack steel tanks, you’ll need a liquid meter to determine the level of hydraulic fluid.

Basically, these tanks are specifically manufactured to resist high and low temperature conditions. They ensure the properties of hydraulic fluid remains the same at all times.

This allows air to get into the tank, thereby protecting the tank from atmospheric pressure. Remember, as the gear pump rotates it creates a vacuum that forces hydraulic fluid into it.

You will mount hydraulic power pack to the other customized steel tank through the steel tank neck. So, you can mount one or two or more power packs on one steel, square customized steel tank.

A coupling is the main device you’ll use to connect your electric motor and hydraulic pump. That is, you’ll connect the shaft of your motor to that of the hydraulic pump.

The type of coupling will depend on the position of your electric motor relative to that of the hydraulic pump. Some of the most common types of coupling include:Flexible coupling; this is when the coupling can handle both parallel and angular misalignment.

To ensure there is a seamless flow of hydraulic fluid from the tank to the cylinder, you’ll need the following:Fittings; this connects the hose to the outlet of the manifold if they don’t match.

Hydraulic pipes and filters play an integral role in hydraulic power pack systems. In this sub-section, you’re going to learn about:Hydraulic suction pipe

As the hydraulic pump rotates, it creates a pressure difference, hence, the fluid flows to the pump. A hydraulic suction pipe is the pipe that connects the tank and the pump.

Hydraulic filters remove debris or impurities in the oil before it is suctioned through the hydraulic pipe to the pump. It helps to keep the hydraulic system clean.

These filters come in different sizes and configurations with some equipped with magnet to remove metallic parts from the hydraulic fluid. This prevents clogging.

These are basic components of hydraulic power packs that depend on electrical signals to send commands to the system. In this subsection, you’ll learn about three major components:Cable remote-push button pendant

Commonly used for single / double acting hydraulic system. There was a key you can lock this remote away from battery, so, nobody can operating power pack without this key. It has four wires, which are 4 meters4 buttons Remote

A hydraulic actuator is the mechanical portion that converts hydraulic power into useful mechanical work. This mechanical work can either be linear motion, rotary motion or oscillatory motion.

A valve actuator refers to the mechanism of opening and closing a valve. Some of the most common types of valve actuators include manual, pneumatic, hydraulic, electric and spring valve actuators.

Linear actuators create motion in a straight line. You can create motion using different mechanisms that may involve the use of mechanical, hydraulic, pneumatic, piezoelectric or electro-mechanical actuators.

The electro-hydraulic actuators are commonly used in applications that require a high degree of precision. They have self-contained actuators, which are operated only by electric power.

In chapter 1, section 1.2 (sorts of hydraulic power pack) and section 1.3 (function of hydraulic power), I did discuss all the vital aspects about single acting and double acting hydraulic cylinders.

Just as a reminder, you should know that hydraulic cylinder is an important hydraulic actuator. It converts hydraulic energy into a mechanical energy we use to perform a number of tasks.

As you have learnt earlier, hydraulic power packs are broadly categorized as either single acting hydraulic cylinder or double acting hydraulic cylinder. So, this fact does not change in hydraulic cylinder actuators.

A position-sensing hydraulic cylinder is used in more advanced systems where it provides an instantaneous analog or digital electronic position feedback information. That is, it indicates the extent of rod extension during any stroke.

Such cylinders may have either an internal or external displacement transducer. However, the internal displacement transducers offer a reliable solution when it comes to this sensing technology.

As you have seen earlier (chapter 1), all these hydraulic power packs have their unique advantages and disadvantages. You will learn more about this in chapter 5.

That is, a hydraulic motor can generate different magnitude of torque at different pressures. Some of the main applications include hydraulic bicycle and hydraulic hybrid vehicle.

Before it begins to rotate, the hydraulic fluid should provide sufficient torque to turn the motor. The torque that the hydraulic fluid provides can be categorized as:

This is the minimum torque you’ll need to start the motor at no load. That is, the hydraulic energy should overcome the internal frictional forces of the motor.

The existing hydraulic motors may be classified into four different categories. These include:Hydraulic gear motors; they include hydraulic and epicyclic gear motors.

The truth is, hydraulic pumps add more energy to the circuit by pushing the fluid while the hydraulic motors act as actuators that change hydraulic energy into rotary motion. Furthermore, hydraulic pumps are coupled to an electric motor.

The concept of hydrostatic transmission is based on the fact that, whenever a pump is connected to a prime mover, it generates fluid flow that drives a hydraulic motor. It is this hydraulic motor that is connected to the load.

To make it more versatile, you can make either the pump or motor variable displacement. You can learn more about this concept here: Understanding Hydrostatic Transmissions.

This is breaking mechanism that uses brake fluid (hydraulic fluid) to stop or control a moving wheel or object. You can review hydraulic power pack applications in chapter one to learn more about this.

Hydraulic fluid is the medium through which power or energy is transferred in hydraulic systems. Some of the most commonly used hydraulic fluids are either mineral or water based solutions.

Basically, these are the basic aspect you need to know about hydraulic fluid. To learn more about these oils then you can click: Engineering Essentials: Hydraulic Fluids.

GRH, since 1986, is the manufacture of hydraulic components such as proportional valves, sectional valves, mono-block valves, hydraulic manifolds, flow control valve( manual and proportional) , gear pumps, gear motors, flow dividers, Orbital motor, Mini power pack, pump + motor assembly, hydraulic power station Applications: Agricultural machinery: tractor , combined harvester, etc, Forest machinery: wood cutter, log splitter , sweeper, lawn mover Construction machinery: excavator, grader, loader, earthmover, etc. Industrial equipment: such as plastic machinery , metallurgy industry, textile machinery, package machine, machining tools, etc Mobile application: trucks, vehicles, boom lift and...