A small, electrically powered pump

A large, electrically driven pump (electropump) for waterworks near the Hengsteysee, Germany.

A pump is a device used to move fluids (liquids or gases) or sometimes slurries by mechanical action. Pumps can be classified into three major groups according to the method they use to move the fluid: direct lift, displacement, and gravity pumps.^[1]

Pumps must have a mechanism which operates them, and consume energy to perform mechanical work by moving the fluid. The activating mechanism is often reciprocating or rotary. Pumps may be operated in many ways, including manual operation, electricity, a combustion engine of some type, and wind action.

Types[link]

Positive displacement pump[link]

A lobe pump

lobe pump internals

Mechanism of a scroll pump

A positive displacement pump causes a fluid to move by trapping a fixed amount of it and then forcing (displacing) that trapped volume into the discharge pipe.

Some positive displacement pumps work using 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 given each cycle of operation.

Positive displacement pump behavior and safety[link]

Positive displacement pumps, unlike centrifugal or roto-dynamic pumps, will in theory produce the same flow at a given speed (RPM) no matter what the discharge pressure. Thus, positive displacement pumps are "constant flow machines". However due to a slight increase in internal leakage as the pressure increases, a truly constant flow rate cannot be achieved.

A positive displacement pump must not be operated against a closed valve on the discharge side of the pump, because it has no shut-off head like centrifugal pumps. A positive displacement pump operating against a closed discharge valve will continue to produce flow and the pressure in the discharge line will increase, until the line bursts or 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 should in general only be used as a safety precaution, an external relief valve installed in the discharge line with a return line back to the suction line or supply tank is recommended.

Positive displacement types[link]

Screw pump

A positive displacement pump can be further classified according to the mechanism used to move the fluid:

• Rotary-type positive displacement: internal gear, screw, shuttle block, flexible vane or sliding vane, circumferential piston, helical twisted roots (e.g. the Wendelkolben pump) or liquid ring vacuum pumps.
• Reciprocating-type positive displacement: piston or diaphragm pumps.
• Linear-type positive displacement: rope pumps and chain pumps.

Rotary positive displacement pumps[link]

Rotary vane pump

Positive displacement rotary pumps move fluid have a rotating mechanism that creates a vacuum that captures and draws in the liquid^{[citation needed]}.

Advantages: Rotary pumps are very efficient^{[citation needed]} because they naturally remove air from the lines, eliminating the need to bleed the air from the lines manually.

Drawbacks: Because of the nature of the pump, the clearance between the rotating pump and the outer edge must be very close, requiring that it rotate at a slow, steady speed. If rotary pumps are operated at high speeds, the fluids will cause erosion, eventually developing enlarged clearances through which liquid can pass, reducing the efficiency of the pump.

Rotary positive displacement pumps can be grouped into three main types:

• Gear pumps - a simple type of rotary pump where the liquid is pushed between two gears.
• Screw pumps - the shape of the internals of this pump usually two screws turning against each other pump the liquid.
• Rotary vane pumps - similar to scroll compressors, consisting of a cylindrical rotor encased in a similarly shaped housing. As the rotor turns, the vanes trap fluid between the rotor and the casing, drawing the fluid through the pump.

Reciprocating positive displacement pumps[link]

Simple hand pump

Hand-operated, reciprocating, positive displacement, water pump in Košice-Ťahanovce, Slovakia (walking beam pump).

Reciprocating pumps are those which cause the fluid to move using one or more oscillating pistons, plungers or membranes (diaphragms), and restrict motion of the fluid to the one desired direction by valves.

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 early days of steam propulsion (19th century) as boiler feed water pumps. Reciprocating pumps are now typically used for pumping highly viscous fluids including concrete and heavy oils, and special applications demanding low flow rates against high resistance. Reciprocating hand pumps were widely used for pumping water from wells; the common bicycle pump 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.

Typical reciprocating pumps are:

• Plunger pumps - a reciprocating plunger pushes the fluid through one or two open valves, closed by suction on the way back.
• Diaphragm pumps - similar to plunger pumps, where the plunger pressurizes hydraulic oil which is used to flex a diaphragm in the pumping cylinder. Diaphragm valves are used to pump hazardous and toxic fluids.
• Piston displacement pumps - usually simple devices for pumping small amounts of liquid or gel manually. An example is the common hand soap pump.
• Radial piston pump

Various positive displacement pumps[link]

The positive displacement principle applies in the following types of pumps:

• rotary lobe pump
• Progressive cavity pump
• rotary gear pump
• piston pump
• diaphragm pump
• screw pump
• gear pump
• Hydraulic pump
• vane pump
• regenerative (peripheral) pump
• peristaltic pump
• rope pump

Gear pump[link]

Gear pump

This is the simplest of rotary positive displacement pumps. It consists of two meshed gears rotating in a closely fitted casing. Fluid is pumped around the outer periphery by being trapped in the tooth spaces. It does not travel back on the meshed part, since the teeth mesh closely in the centre. It is widely used on car engine oil pumps, and also in various hydraulic power packs.

Screw pump[link]

Screw pumps are a more complicated type of rotary pumps, featuring two or three screws with opposing thread —- that is, one screw turns clockwise, and the other counterclockwise. The screws are each mounted on shafts that run parallel to each other; the shafts also have gears on them that mesh with each other in order to turn the shafts together and keep everything in place. The turning of the screws, and consequently the shafts to which they are mounted, draws the fluid through the pump. As with other forms of rotary pumps, the clearance between moving parts and the pump's casing is minimal.

Progressing cavity pump[link]

Widely used for pumping difficult materials such as sewage sludge contaminated with large particles, this pump consists of a helical shaped 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, although of course in reality it is made from one casting. This shaft fits inside a heavy duty rubber sleeve, of wall thickness typically x also. As the shaft rotates, fluid is gradually forced up the rubber sleeve. Such pumps can develop very high pressure at quite low volumes.

Roots-type pumps[link]

Named after the Roots brothers who designed and invented it, this lobe pump works by displacing the liquid trapped between two long helical twisted rotors, each fitting 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 results with gentle performance, more fit for some applications.

Some applications are:

• High capacity industrial air compressors
• Roots superchargers on internal combustion engines.
• A brand of civil defense siren, the Federal Signal Corporation's Thunderbolt.

Peristaltic pump[link]

A peristaltic pump is a type of positive displacement pump used for pumping a variety of fluids. The fluid is contained within a flexible tube fitted inside a circular pump casing (though linear peristaltic pumps have been made). A rotor with a number of "rollers", "shoes" or "wipers" attached to the external circumference compresses the flexible tube. As the rotor turns, the part of the tube under compression closes (or "occludes") thus forcing the fluid to be pumped to move through the tube. Additionally, as the tube opens to its natural state after the passing of the cam ("restitution") fluid flow is induced to the pump. This process is called peristalsis and is used in many biological systems such as the gastrointestinal tract.

Plunger pumps[link]

A plunger pump compared to a piston pump

Plunger pumps are reciprocating positive displacement pumps.

They consist of a cylinder with a reciprocating plunger in them. The suction and discharge valves are mounted in the head of the cylinder. In the suction stroke the plunger retracts and the suction valves open causing suction of fluid into the cylinder. In the forward stroke the plunger pushes the liquid out of the discharge valve.

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 "water hammer" may be a serious problem. In general the problems are compensated for by using two or more cylinders not working in phase with each other.

Compressed-air-powered double-diaphragm pumps[link]

One modern application of positive displacement diaphragm 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. Commonly seen in all areas of industry from shipping to processing, Wilden Pumps, Graco, SandPiper or ARO are generally the larger of the brands. They are relatively inexpensive and can be used for almost any duty from pumping water out of bunds, to pumping hydrochloric acid from secure storage (dependent on how the pump is manufactured – elastomers / body construction). Lift is normally limited to roughly 6m although heads can reach almost 200 Psi.^{[citation needed]}.

Rope pumps[link]

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 PVC pipe are sufficient to make a simple rope pump. For this reason they have become extremely popular around the world since the 1980s. Rope pump efficiency has been studied by grass roots organizations and the techniques for making and running them have been continuously improved.^[2]

Impulse pumps[link]

The pulser pump

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 which can push part of the liquid upwards.

Impulse pumps include:

• Hydraulic ram pumps - uses pressure built up internally from released gas in liquid flow. (see below)
• Pulser pumps - run with natural resources, by kinetic energy only.
• Airlift pumps - run on air inserted into pipe, pushing up the water, when bubbles move upward, or on pressure inside pipe pushing water up.

Hydraulic ram pumps[link]

Airlift pump vs. Geyser pump

A hydraulic ram is a water pump powered by hydropower.

It functions as a hydraulic transformer that takes in water at one "hydraulic head" (pressure) and 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 allows a portion of the input water that powers the pump to be lifted to a point higher than where the water originally 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.

Velocity pumps[link]

A centrifugal pump uses a spinning "impeller" which has backward-swept arms

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 can be explained by the First law of thermodynamics or more specifically by Bernoulli's principle.

Dynamic pumps can be further subdivided according to the means in which the velocity gain is achieved.^[3]

These types of pumps have a number of characteristics:

1. Continuous energy
2. Conversion of added energy to increase in kinetic energy (increase in velocity)
3. Conversion of increased velocity (kinetic energy) to an increase in pressure head

One practical difference between dynamic and positive displacement pumps is their ability to operate under closed valve conditions. Positive displacement pumps physically displace the fluid; hence closing a valve downstream of a positive displacement pump will result in a continual build up in pressure resulting in mechanical failure of either pipeline or pump. Dynamic pumps differ in that they can be safely operated under closed valve conditions (for short periods of time).

Centrifugal pump[link]

Centrifugal pump

Open Type Centrifugal Pump Impeller

A centrifugal pump is a rotodynamic pump that uses a rotating impeller to increase the pressure and flow rate of a fluid. Centrifugal pumps are the most common type of pump used to move liquids through a piping system. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward or axially into a diffuser or volute chamber, from where it exits into the downstream piping system. Centrifugal pumps are typically used for large discharge through smaller heads.

Centrifugal pumps are most often associated with the radial flow type. However, the term "centrifugal pump" can be used to describe all impeller type rotodynamic pumps^[4] including the radial, axial and mixed flow variations.

Radial flow pumps[link]

Often simply referred to as centrifugal pumps. The fluid enters along the axial plane, is accelerated by the impeller and exits at right angles to the shaft (radially). Radial flow pumps operate at higher pressures and lower flow rates than axial and mixed flow pumps.

Axial flow pumps[link]

Axial pump (propeller in pipe)

Axial flow pumps differ from radial flow in that the fluid enters and exits along the same direction parallel to the rotating shaft. The fluid is not accelerated but instead "lifted" by the action of the impeller. They may be likened to a propeller spinning in a length of tube. Axial flow pumps operate at much lower pressures and higher flow rates than radial flow pumps.

Mixed flow pumps[link]

Mixed flow pumps, as the name suggests, function as a compromise between radial and axial flow pumps, the fluid experiences both radial acceleration and lift and exits the impeller somewhere between 0–90 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.

Eductor-jet pump[link]

This uses a jet, often of steam, to create a low pressure. This low pressure sucks in fluid and propels it into a higher pressure region.

Gravity pumps[link]

Gravity pumps include the syphon and Heron's fountain – and there also important qanat or foggara systems which simply use downhill flow to take water from far-underground aquifers in high areas to consumers at lower elevations. The hydraulic ram is also sometimes referred to as a gravity pump.

Steam pumps[link]

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, the Pulsometer steam pump or the Steam injection 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 pumps[link]

Valveless pumping assists in fluid transport in various biomedical and engineering systems. In a valveless pumping system, no valves 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 discernable chambers and valves. In microfluidics, valveless impedance pump have been fabricated, and are expected to be particularly suitable for handling sensitive biofluids.

Pump repairs[link]

Examining pump repair records and MTBF (mean time between failures) 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).^[5]

In early 2005, Gordon Buck, John Crane Inc.’s chief engineer for Field Operations in Baton Rouge, LA, 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 can be expected elsewhere. In chemical plants, pumps have traditionally been "throw-away" items as chemical attack can result in limited 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 can be fitted. Unless the pump user upgrades the seal chamber, only the more compact and simple versions can be accommodated. Without this upgrading, lifetimes in chemical installations are generally believed to be 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 $2600 to $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 $5,000 on average. This includes costs for material, parts, labor and overhead. Let us now assume that the MTBF for a particular pump is 12 months and that it could be extended to 18 months. This would result in a cost avoidance of $2,500/yr—which is greater than the premium one would pay for the reliability-upgraded centrifugal pump.^[5][6][7]

Applications[link]

Metering pump for gasoline and additives.

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.

Priming a pump[link]

Liquid and slurry pumps can lose prime and this will require the pump to be primed by adding liquid to the pump and inlet pipes to get the pump started. Loss of "prime" is usually due to ingestion of air into the pump. The clearances and displacement ratios in pumps used for liquids and other more viscous fluids cannot displace the air due to its lower density.

Pumps as public water supplies[link]

First European depiction of a piston pump, by Taccola, c.1450.^[8]

One sort of pump once common worldwide was a hand-powered water pump, or 'pitcher pump'. It would be installed over a community water well that was used by people in the days before piped water supplies.

In parts of the British Isles, it was often called "the parish pump". Although such community pumps are no longer common, the expression "parish pump" is still used. It derives from the kind of the chatter and conversation that might be heard as people congregated to draw water from the community water pump, and is now used to describe a place or forum where matter of purely local interest is discussed.^[9]

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.^{[citation needed]}

Sealing multiphase pumping applications[link]

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.

For midstream and upstream operations, multiphase pumps can be located onshore or offshore and can be connected to single or multiple wellheads. Basically, multiphase pumps are used to transport the untreated flow stream produced from oil wells to downstream processes or gathering facilities. This means that the pump may handle a flow stream (well stream) from 100 percent gas to 100 percent liquid and every imaginable combination in between. The flow stream can also contain abrasives such as sand and dirt. Multiphase pumps are designed to operate under changing/fluctuating process conditions. Multiphase pumping also helps eliminate emissions of greenhouse gases as operators strive to minimize the flaring of gas and the venting of tanks where possible.^[10]

Types and features of multiphase pumps[link]

Helico-Axial Pumps (Centrifugal) A rotodynamic pump with one single shaft requiring two mechanical seals. This pump utilizes an open-type axial impeller. This pump type is often referred to as a "Poseidon Pump" and can be described as a cross between an axial compressor and a centrifugal pump.

'Twin Screw (Positive Displacement)' The twin screw pump is constructed of two intermeshing screws that force the movement of 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.

Progressive Cavity Pumps (Positive Displacement) Progressive cavity pumps are single-screw types typically used in shallow wells or at the surface. This pump is mainly used on surface applications where the pumped fluid may contain a considerable amount of solids such as sand and dirt.

Electric Submersible Pumps (Centrifugal) 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.

Buffer Tank 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, smoothes 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.^[10][11][12]

Specifications[link]

Pumps are commonly rated by horsepower, flow rate, outlet pressure in metres (or feet) of head, inlet suction in suction feet (or metres) of head. The head can be simplified as the number of feet or metres the pump can raise or lower a column of water at atmospheric pressure.

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.

Pump material[link]

The pump material can be Stainless steel (SS 316 or SS 304), cast iron etc. It depends on the application of the pump. In the water industry and for pharma applications SS 316 is normally used, as stainless steel gives better results at high temperatures.

Pumping power[link]

The power imparted into a fluid will increase 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:

Failed to parse (Missing texvc executable; please see math/README to configure.): P = \frac{\Delta P Q}{\eta}

where ΔP is the change in total pressure between the inlet and outlet (in Pa), and Q, the fluid flowrate is given in m^3/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 will depend upon the pump's configuration and operating conditions (such as rotational speed, fluid density and viscosity etc.)

Failed to parse (Missing texvc executable; please see math/README to configure.): \Delta P = {(v_2^2 - v_1^2) \over 2}+\Delta z g+{\Delta p_{\mathrm{static}}\over\rho}

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[link]

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) 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).

One important part of system design involves matching the pipeline head loss-flow characteristic with the appropriate pump or pumps in order to operate at or close to the point of maximum efficiency.

Pump efficiency is an important aspect and pumps should be regularly tested. Thermodynamic pump testing is one method.

Pump selection is done by performance curve which is curve between pressure head and flow rate, with power supply also taken care of. Pumps are normally available that run at 50 Hz or 60 Hz.

Pump testing[link]

To minimise energy use, and to ensure that pumps are correctly matched to the duty expected pumps, and pumping stations should be regularly tested.

In water supply application, which are usually fitted with centrifugal pumps, individual large pumps should be 70 - 80% efficient. They should be individually tested to ensure they are in the appropriate range, and replaced or prepared as appropriate.

Pumping stations should also be tested collectively, because where pumps can run in combination to meet a given demand, it is often possible for very inefficient combination of pumps to occur. For example. it is perfectly possible to have a large and a small pump operating in parallel, with the smaller pump not delivering any water, but merely consuming energy. See Pump station manager

Pumps are readily tested by fitting a flow meter, measuring the pressure difference between inlet and outlet, and measuring the power consumed.

Another method is thermodynamic pump testing where only the temperature rise and power consumed need be measured.

See also[link]

References[link]

Further reading[link]

• Australian Pump Manufacturers' Association. Australian Pump Technical Handbook, 3rd edition. Canberra: Australian Pump Manufacturers' Association, 1987. ISBN 0-7316-7043-4.
• Hicks, Tyler G. and Theodore W. Edwards. Pump Application Engineering. McGraw-Hill Book Company.1971. ISBN 07-028741-4
• Robbins, L. B. "Homemade Water Pressure Systems". Popular Science, February 1919, pages 83–84. Article about how a homeowner can easily build a pressurized home water system that does not use electricity.

External links[link]

Wikimedia Commons has media related to: Pumps

• www.pumpschool.com—Pump education devoted primarily to rotary positive displacement pumps
• Drinking Water System

"Pumped Up Kicks" is a song by American indie pop band Foster the People. It was released as the group's debut single in September 2010, and the following year was included on their EP Foster the People and their debut album Torches. "Pumped Up Kicks" became the group's breakthrough hit and was one of the most popular songs of 2011. The song was written and recorded by frontman Mark Foster while he was working as a commercial jingle writer. Contrasting with the upbeat musical composition, the lyrics describe the homicidal thoughts of a troubled youth.

The track received considerable attention after it was posted online in 2010 as a free download, and it helped the group garner a multi-album record deal with Columbia Records imprint Startime International before they had issued a commercial release. The song became both a crossover hit and a sleeper hit in 2011, as it received significant airplay on modern rock and contemporary hit radio stations. The song spent eight consecutive weeks at number three on the Billboard Hot 100 chart in the United States, making it the first Billboard Alternative Songs number-one single to crack the U.S. top 5 since Kings of Leon's "Use Somebody" in 2009. The song was widely praised by critics, and it has been licensed for use in a wide range of popular media since its release. "Pumped Up Kicks" received a Grammy Award nomination for Best Pop Duo/Group Performance.

Recording[link]

Soon after Mark Foster formed Foster the People in 2009, he wrote and recorded "Pumped Up Kicks" in five hours while working as a commercial jingle writer at Mophonics in Los Angeles.^[1][2] Thinking that he was just recording a demo, he played all of the instruments on the song. Ultimately, Foster's original version of the song is what ended up being released.^[3]

Composition and inspiration[link]

The lyrics to "Pumped Up Kicks" are written from the perspective of a troubled and delusional youth with homicidal thoughts.^[3] The lines in the chorus warn potential victims to "outrun my gun" and that they "better run, better run, faster than my bullet". Foster said, "I was trying to get inside the head of an isolated, psychotic kid."^[3] He wrote the lyrics in order to "bring awareness" to the issue of gun violence amongst youth, which he feels is an epidemic perpetuated by "lack of family, lack of love, and isolation".^[5][6] The song's title refers to shoes that the narrator's peers wear as a status symbol.^[7] The issue of youth violence is a matter close to the group. Foster was bullied in high school, while bassist Cubbie Fink has a cousin who survived the Columbine High School massacre in 1999. Fink said of his cousin's experience, "She was actually in the library when everything went down, so I actually flew out to be with her the day after it happened and experienced the trauma surrounding it and saw how affected she was by it. She is as close as a sister, so obviously, it affected me deeply. So to be able to have a song to create a platform to talk about this stuff has been good for us."^[4]

Contrasting with the dark lyrics of the song, the music, which was written first, is upbeat. Foster said, "It's a 'fuck you' song to the hipsters in a way—but it's a song the hipsters are going to want to dance to."^[3] Jeffery Berg of Frontier Psychiatrist said, "I was so engrossed with the cheery melody of its chorus that it took me a few listens to discover that the lyrics suggest dark, Columbine revenge."^[8]

Due to the opening lyrics, "Robert's got a quick hand," many have speculated that the song is a reference to Robert Hawkins, perpetrator of Omaha's Westroads Mall shooting. The band's publicist refutes this with "This is completely false. The character name in the song is just a coincidence."^[9] For play on the television channels MTV and MTVu, the words "gun" and "bullet" were removed from the song's chorus.^[10] Foster believes many have misinterpreted the song's meaning, and he has written letters to his record label and called radio stations to complain. He explained, "The song is not about condoning violence at all. It's the complete opposite. The song is an amazing platform to have a conversation with your kids about something that shouldn't be ignored, to talk about it in a loving way."^[2]

Release and promotion[link]

Initial attention[link]

"Pumped Up Kicks" was written by Mark Foster (pictured) while he was working as a jingle writer. Initially posted on his website as a free download, the song grew in popularity through viral outlets and earned the band a record deal.

"Pumped Up Kicks" drew considerable attention online after Foster posted the song on his website as a free download in early 2010; Nylon magazine used the track in an online advertising campaign,^[11] and through various blogs, it went viral.^[12] Foster the People first performed the song live at the Stand Up Charity Benefit in Venice in February.^[13] The group, yet to be signed, reached additional audiences with performances at the South by Southwest music festival in March 2010.^[14] Foster was emailed by many people about the song, and needing professional guidance, he contacted artist manager Brent Kredel at Monotone, Inc., saying, "Everyone is calling me and emailing me—what do I do? Who are the good guys, who are the bad guys?" Kredel recalled that "He went from the guy who couldn't get a hold of anyone to being the guy who had hundreds of emails in his inbox." Kredel and Brett Williams were subsequently hired to co-manage Foster the People, and they helped the group get a multi-album record deal with Columbia Records imprint Startime International in May 2010.^[11]

"Pumped Up Kicks" was licensed for use in a July 2010 episode of the TV series Entourage, the first of many instances in which Foster the People's music was licensed in popular media.^[11] Wishing to release a record that would back up the song's success, the group wrote new material between July–September 2010.^[11] The song received its first widespread radio play in July 2010 on Sirius XM's Alt Nation channel and the Australian radio station Triple J.^[15] The song was released as their debut single on September 14, 2010.^{[citation needed]} In November, the University of Maryland's radio station WMUC played the song, marking its debut on US terrestrial radio.^[16] The song placed at number 32 in the Triple J's Hottest 100 for 2010,^[17] a big achievement due to the band being relatively unknown in Australia. Still, the group was inexperienced as a live act, and as a result, their booking agent Tom Windish secured them several club shows "to help them get their sea legs." Foster the People promoted these concerts in January 2011 by emailing fans who had downloaded "Pumped Up Kicks" from their website, notifying them of the shows. The group continued to grow its fanbase with a month-long residency of concerts in January at The Echo nightclub in Los Angeles. By the group's third show at the venue, according to Windish, "there were hundreds of people trying to get in outside... It was an obvious turning point that could be measured in numbers." The residency also drew the attention of music supervisors in attendance who would later help the group license their music.^[11]

Commercial breakthrough[link]

In January 2011, the band issued their first commercial non-single release, a self-titled EP on which "Pumped Up Kicks" appeared. Around the same time, many alternative radio stations began playing "Pumped Up Kicks", including Los Angeles terrestrial stations KROQ-FM and KYSR, and it continued to gain popularity on Alt Nation.^[11] Mark Foster credits Sirius XM's airplay with the song's success, saying, "Alt Nation played our music before any other radio outlet in the country."^[18] On January 29, the song debuted on Billboard's Rock Songs chart and a week later, it debuted on the Alternative Songs chart. In May, the track debuted at number 96 on the Billboard Hot 100, and later that month, the group released their first full-length studio album, Torches, on which "Pumped Up Kicks" appears.^[11] On May 23, 2011, BBC Radio 1 DJ Greg James selected the song as his Record of the Week, which ran until May 27. During this time, James released an accompanying video of him dancing to the song which he entitled and promoted "The Bum Dance".^[19]

The song proved to be a crossover hit, peaking at number three on the Rock Songs chart in July and number one on the Alternative Songs chart in June, while breaking into the top 40 of the Hot 100 in late July and appearing on the Adult Top 40 and Mainstream Top 40 charts. Columbia senior VP of promotion Lee Leipsner said, "It was one of the only alternative bands I remember in a while that you could actually dance to. And the fact that the record has a groove and rhythmic feel to it—not heavy guitar-based at all—gave us a wide opportunity to cross the record." He credits the song's crossover success and push into the top 40 to a June presentation of new music by Clear Channel president of national programming platforms Tom Poleman. According to Leipsner, "After we showed our presentation, we had so many Clear Channel major-market programmers come up to us and say, 'The record I want to play besides Adele is Foster the People.'" "Pumped Up Kicks" peaked at number three on the Hot 100, spending eight consecutive weeks at the position.^[11] It has been certified 3× platinum in the US, Canada,^[20][21] and Australia,^[22] while receiving a gold certification in Germany.^[23] The song ranked as the sixth-best-selling digital song of 2011, selling 3.61 million copies.^[24]

Music video[link]

The music video, directed by Josef Geiger, was filmed at multiple locations in Los Angeles with insert footage from San Francisco^{[citation needed]} and features the band playing a show. There are also cuts to band members doing other activities, such as playing frisbee and surfing. The video peaked at #21 on the MuchMusic Countdown in Canada.^[25] The video has received over 83 million views on YouTube.^[2]

Reception[link]

Critical reaction[link]

"Pumped Up Kicks" received positive reviews from critics. Barry Walters of Spin said that with the song as their debut single, Foster the People "announce themselves as major players".^[26] Jon Dolan of Rolling Stone described the song as having a "slinky groove, misty guitar flange and delicious astral-wimp vocals".^[27] Rob Webb of NME drew some parallels between the song and other indie pop hits like "Young Folks", "Paris", and "Kids" describing its rise in popularity as thus: "artist writes (undeniably brilliant) pop song, makes it catchy as hell, but quirky enough for the 'cool' crowd, song subsequently gets some big pimping from every blog/radio station/Hype Machine user on the planet and, seemingly overnight, becomes utterly, irritatingly inescapable."^[28] August Brown of the Los Angeles Times called it a "reputation-making single" that "cakes Foster in Strokes-y vocal distortion atop a loping synth bass".^[29] Jon Pareles of The New York Times called it a "pop ditty with dazed, dweeby vocals and a handclapping chorus that warns, 'You better run, better run, outrun my gun'".^[30] BBC Music's Mark Beaumont called the song a "psychedelic block party skipping tune". Reflecting on the song's fusion of various musical elements, Beaumont said the song is a prime example of how they "adapt Animal Collective's art-tronic adventurousness to incorporate the funky danceability of Scissor Sisters, the fuzzy pop catchiness of 'Kids' and the knack of throwing in deceptively downbeat twists akin to Girls, Sleigh Bells or Smith Westerns".^[31] Matt Collar of Allmusic said the song, like other tracks from the album, is "catchy, electro-lite dance-pop that fits nicely next to such contemporaries as MGMT and Phoenix".^[32] The Guardian's Michael Hann was less receptive, saying it "amounts to little more than a bassline and a chorus" and that "It's as irresistible as it is infuriating".^[33]

Accolades[link]

A Rolling Stone readers poll named it the second-best song of summer 2011.^[34] Claire Suddath of Time magazine named "Pumped Up Kicks" one of the Top 10 Songs of 2011.^[35] In end-of-year polls, writers for Rolling Stone selected "Pumped Up Kicks" as the 11th-best song of 2011,^[36] while the publication's readers voted it the year's sixth-best song.^[37] A listeners poll by Toronto radio station CFNY-FM (102.1 The Edge) voted it #1 in a list of the top 102 new rock songs of 2011.^[38] Entertainment Weekly selected the song as the second-best single of 2011.^[39] NME ranked it number 21 on its list of the "50 Best Tracks of 2011", writing, "Unusually for a song so omnipresent, listening to its hyper-upbeat melodies about a psycho high-school kid-killer is still an enjoyable experience."^[40] The magazine's readers voted "Pumped Up Kicks" the year's eighth-best song.^[41] At the end of 2011, the song received a Grammy Award nomination for Best Pop Duo/Group Performance.^[42]

Impact[link]

In an article for The Huffington Post, DJ Louie XIV singled out "Pumped Up Kicks" as one of several popular songs that helped usher in the return of commercially successful indie music. In discussing the growing acceptance of fringe cultures, he wrote, "It seems only fitting, then, that the soundtrack to this time period should be music that was itself once viewed as fringe culture."^[43] Reflecting on the song's success, Gary Trust, the associate director of charts/radio for Billboard, said, "They're walking a tightrope very well in terms of eras, formats and styles. When you mix all that together, it becomes a very good recipe for a hit that works on so many levels. It's the perfect song." Foster said of the song, "There's a spirit there and that's what people resonate with. 'Pumped Up Kicks' wasn't an accident."^[2]

Use in popular media[link]

The song was used in TV series such as Entourage,^[44] Gossip Girl, CSI:NY, Cougar Town, Homeland, Warehouse 13 and The Vampire Diaries and also in the 2011 films Friends with Benefits^[11] and Fright Night, as well as sampled in Shawn Chrystopher's song "All the Other Kids", from his 2010 hip-hop album You, and Only You. The whistling part of the song is part of the rotation of bumper music played on the Michael Medved syndicated radio program. The song is also used on the BBC programme Match of the Day. On October 8, 2011, Foster the People performed the song on Saturday Night Live. The song was also used in Australian beer XXXX's "XXXX Summer Bright Lager" television commercial.^[45]

Cover versions and remixes[link]

The official remix of the single was released by New York City-duo The Knocks in April 2011, under the name "Pumped Up Kicks (The Knocks Speeding Bullet Remix)", and was made available to subscribers to the band's email list. The song was covered by Weezer during their 2011 North American Tour, at the Orange County Fair on August 4, 2011. Weezer also played the song during their grandstand performance at the Minnesota State Fair on September 3, 2011.^[46] Mark Foster said in reaction, "Nine years ago, I met Rivers Cuomo at a party, and I had my acoustic guitar with me. He taught me how to play 'Say It Ain't So'. So nine years later, to watch him play one of my songs - it was wild. I can't wait to meet him and remind him of that story."^[47]

In 2011, The Kooks covered song in BBC Radio 1's Live Lounge.^[48] Australian musician Owl Eyes performed a version of "Pumped Up Kicks" for Triple J's Like a Version. In the Triple J Hottest 100, 2011, Owl Eyes' version came in at 28, four positions higher than the original did the previous year. Singer-songwriters Dani Shay and Justin Chase covered the song in a theatrical music video October 2011^[49] and released the single in November 2011.^[50] A parody of the song was performed by Taylor Swift and Zac Efron on The Ellen DeGeneres Show, as a serenade to the host. Its lyrics were about how they felt weird when Ellen used to put them as a couple when they were not.^[51] On March 12, 2012 singers Lex Land and Charlotte Sometimes performed the song during the second "Battle Round" episode of The Voice.^[52]

Track listing[link]

Charts[link]

Release history[link]

See also[link]

• List of number-one Billboard Alternative Songs of 2011
• List of number-one dance airplay hits of 2011 (U.S.)
• List of number-one singles of 2012 (Australia)

References[link]