mud pump selection criteria brands

When choosing a size and type of mud pump for your drilling project, there are several factors to consider. These would include not only cost and size of pump that best fits your drilling rig, but also the diameter, depth and hole conditions you are drilling through. I know that this sounds like a lot to consider, but if you are set up the right way before the job starts, you will thank me later.

Recommended practice is to maintain a minimum of 100 to 150 feet per minute of uphole velocity for drill cuttings. Larger diameter wells for irrigation, agriculture or municipalities may violate this rule, because it may not be economically feasible to pump this much mud for the job. Uphole velocity is determined by the flow rate of the mud system, diameter of the borehole and the diameter of the drill pipe. There are many tools, including handbooks, rule of thumb, slide rule calculators and now apps on your handheld device, to calculate velocity. It is always good to remember the time it takes to get the cuttings off the bottom of the well. If you are drilling at 200 feet, then a 100-foot-per-minute velocity means that it would take two minutes to get the cuttings out of the hole. This is always a good reminder of what you are drilling through and how long ago it was that you drilled it. Ground conditions and rock formations are ever changing as you go deeper. Wouldn’t it be nice if they all remained the same?

Centrifugal-style mud pumps are very popular in our industry due to their size and weight, as well as flow rate capacity for an affordable price. There are many models and brands out there, and most of them are very good value. How does a centrifugal mud pump work? The rotation of the impeller accelerates the fluid into the volute or diffuser chamber. The added energy from the acceleration increases the velocity and pressure of the fluid. These pumps are known to be very inefficient. This means that it takes more energy to increase the flow and pressure of the fluid when compared to a piston-style pump. However, you have a significant advantage in flow rates from a centrifugal pump versus a piston pump. If you are drilling deeper wells with heavier cuttings, you will be forced at some point to use a piston-style mud pump. They have much higher efficiencies in transferring the input energy into flow and pressure, therefore resulting in much higher pressure capabilities.

Piston-style mud pumps utilize a piston or plunger that travels back and forth in a chamber known as a cylinder. These pumps are also called “positive displacement” pumps because they literally push the fluid forward. This fluid builds up pressure and forces a spring-loaded valve to open and allow the fluid to escape into the discharge piping of the pump and then down the borehole. Since the expansion process is much smaller (almost insignificant) compared to a centrifugal pump, there is much lower energy loss. Plunger-style pumps can develop upwards of 15,000 psi for well treatments and hydraulic fracturing. Centrifugal pumps, in comparison, usually operate below 300 psi. If you are comparing most drilling pumps, centrifugal pumps operate from 60 to 125 psi and piston pumps operate around 150 to 300 psi. There are many exceptions and special applications for drilling, but these numbers should cover 80 percent of all equipment operating out there.

The restriction of putting a piston-style mud pump onto drilling rigs has always been the physical size and weight to provide adequate flow and pressure to your drilling fluid. Because of this, the industry needed a new solution to this age-old issue.

As the senior design engineer for Ingersoll-Rand’s Deephole Drilling Business Unit, I had the distinct pleasure of working with him and incorporating his Centerline Mud Pump into our drilling rig platforms.

In the late ’90s — and perhaps even earlier —  Ingersoll-Rand had tried several times to develop a hydraulic-driven mud pump that would last an acceptable life- and duty-cycle for a well drilling contractor. With all of our resources and design wisdom, we were unable to solve this problem. Not only did Miller provide a solution, thus saving the size and weight of a typical gear-driven mud pump, he also provided a new offering — a mono-cylinder mud pump. This double-acting piston pump provided as much mud flow and pressure as a standard 5 X 6 duplex pump with incredible size and weight savings.

The true innovation was providing the well driller a solution for their mud pump requirements that was the right size and weight to integrate into both existing and new drilling rigs. Regardless of drill rig manufacturer and hydraulic system design, Centerline has provided a mud pump integration on hundreds of customer’s drilling rigs. Both mono-cylinder and duplex-cylinder pumps can fit nicely on the deck, across the frame or even be configured for under-deck mounting. This would not be possible with conventional mud pump designs.

The second generation design for the Centerline Mud Pump is expected later this year, and I believe it will be a true game changer for this industry. It also will open up the application to many other industries that require a heavier-duty cycle for a piston pump application.

The 2,200-hp mud pump for offshore applications is a single-acting reciprocating triplex mud pump designed for high fluid flow rates, even at low operating speeds, and with a long stroke design. These features reduce the number of load reversals in critical components and increase the life of fluid end parts.

The pump’s critical components are strategically placed to make maintenance and inspection far easier and safer. The two-piece, quick-release piston rod lets you remove the piston without disturbing the liner, minimizing downtime when you’re replacing fluid parts.

A comprehensive range of mud pumping, mixing, and processing equipment is designed to streamline many essential but time-consuming operational and maintenance procedures, improve operator safety and productivity, and reduce costly system downtime.

A mud pump (sometimes referred to as a mud drilling pump or drilling mud pump), is a reciprocating piston/plunger pump designed to circulate drilling fluid under high pressure (up to 7,500 psi or 52,000 kPa) down the drill string and back up the annulus. A mud pump is an important part of the equipment used for oil well drilling and manufactured according to API specification 7K.

The advantages of the drilling mud pump include the ability to move high-solids-content fluids laden with abrasives, the ability to pump large particles, ease of operation and maintenance, reliability, and the ability to operate over a wide range of pressures and flow rates by changing the diameter of pump liners and pistons.

As an important equipment for oilfield drilling operation, a drilling mud pump delivers circulating high-pressure drilling fluid or drilling mud to the bottom of the oil well, flushes the bottom of the well, breaks the rock, cools, lubricates and clean the drill bit, and carries the cuttings back to the ground.

The drilling mud is also used to suspend and carry out drill cuttings from the drill bits as it is brought in and out of the hole. This ensures that the drill bit does not clog and overheat, and makes the entire drilling operation smooth and safe.

Rotational power is supplied to the mud pump through an external power source like a diesel engine or electric motor. The power end of the mud pump converts the rotational energy through a crankshaft to a reciprocating motion of pistons.

The pistons move back and forth in mud pump liners, exerting a force on the cylinder chamber. During the retraction of the piston, valves open to allow the fluid to be drawn into the cylinder. Once the piston has fully retracted, it is pushed back into the cylinder.

abstractNote = {Based on extensive research, development, and field testing of mud pumps and accessory equipment, this book offers cost-saving methods in operation and maintenance of triplex and duplex pumps. It covers practical engineering concerns such as pressure losses from friction in the piping and inertia in the drilling mud; suction dampeners in pump operation; charging the suction pipe for greater efficiency and smoother operation; hydraulic and mechanical knocking; hydraulic pressure losses; discharge lines.},

Since horizontal directional drilling (HDD) work tends to be slower in the winter months, particularly when the ground is frozen, winter is a prime time to inspect the power end of the pump and prevent downtime on the job later.

If one waits until an audible problem can be detected, it is often very expensive to repair. All smaller HDD pumps – 100 hp and smaller — tend to use the same type of internal components regardless of the manufacturer.

The largest load bearing area of the pump is the crosshead pin and bushing area. Wear can be detected by locking the intermittent or piston rod with a pipe wrench and rotating the crank shaft slightly. If one can feel any slack it can only be coming from the pin and bushing or the connecting rod bearing. It then becomes necessary to remove the connecting rod assembly consisting of the connecting rod and cross head. If slack is determined in the pin bushing, it will be necessary to press out the pin and inspect the bushing and the crosshead pin in the eye of the connecting rod. Some manufacturers ship bushings that are designed to fit. Others ship them and they have to be reamed to fit the pin after the bushing is installed. The installation instructions and dimensional fits are provided by the manufacturer in the pump manual.

The next area of concern is the connecting rod bearings themselves. If visual wear can be seen, use a micrometer and measure the crankshaft journals to make sure they are not out of round. If the journals check out, then all is needed is new connecting rod bearings. Some manufactures utilize shims to get the correct fit to the journal. Others provide automotive style bearings that only require correct torque to the rod cap for correct installation. There are pros and cons concerning automotive style vs shim bearings. Shim type bearings does allow for oversized connecting rod bearing should the journals be worn. This allows for turning down the crank journals a few thousands and utilizing a larger connecting rod bearing. If a pump uses automotive style precision bearings and the journals are out of round, it is necessary to replace the crankshaft.

Wiper box packing keeps the oil within the power frame and external contamination from entering the power end. The packing is easy to inspect and essential for longevity of the power end. The wiper box packing must remain in excellent condition at all times. Allowing the pump to set for extended periods of time or letting external contamination build on the packing shortens the lifespan.

If one waits until an audible problem can be detected, it is often very expensive to repair. All smaller HDD pumps – 100 hp and smaller — tend to use the same type of internal components regardless of the manufacturer.

Inspection of the power end allows the owner to dictate when repairs are necessary rather than allowing the pump to dictate during the middle of a job when repair is required. If problems are detected early, repair is relatively inexpensive. If a problem is not detected early, that problem often leads to more unnecessary wear and affects other components of the pump. An early fix to any problem is relatively inexpensive. Allowing the problem to continue can often cost several thousands of dollars and downtime on a job.

Many things go into getting the most life out of your mud pump and its components — all important to extend the usage of this vital piece of equipment on an HDD jobsite. Some of the most important key points are covered below.

The most important thing you can do is service your pump, per the manufacturer’s requirements. We get plenty of pumps in the shop for service work that look like they have been abused for years without having basic maintenance,  such as regular oil changes. You wouldn’t dream of treating your personal vehicle like that, so why would you treat your pump like that.

Check the oil daily and change the oil regularly. If you find water or drilling mud contamination in the oil, change the oil as soon as possible. Failure to do so will most likely leave you a substantial bill to rebuild the gear end, which could have been avoided if proper maintenance procedures would have been followed. Water in the oil does not allow the oil to perform correctly, which will burn up your gear end. Drilling mud in your gear end will act as a lapping compound and will wear out all of the bearing surfaces in your pump. Either way it will be costly. The main reasons for having water or drilling mud in the gear end of your pump is because your pony rod packing is failing and/or you have let your liners and pistons get severely worn. Indication of this is fluid that should be contained inside the fluid end of your pump is now moving past your piston and spraying into the cradle of the pump, which forces its way past the pony rod packing. Pony rod packing is meant to keep the oil in the gear end and the liner wash fluid out of the gear end. Even with brand new packing, you can have water or drilling fluid enter the gear end if it is sprayed with sufficient force, because a piston or liner is worn out.

There is also usually a valve on the inlet of the spray bar. This valve should be closed enough so that liner wash fluid does not spray all over the top of the pump and other components.

Liner wash fluid can be comprised of different fluids, but we recommend just using clean water. In extremely cold conditions, you can use RV antifreeze. The liner wash or rod wash system is usually a closed loop type of system, consisting of a tank, a small pump and a spray bar. The pump will move fluid from the tank through the spray bar, and onto the inside of the liner to cool the liner, preventing scorching. The fluid will then collect in the bottom of the cradle of the pump and drain back down into the collection tank below the cradle and repeat the cycle. It is important to have clean fluid no matter what fluid you use. If your liners are leaking and the tank is full of drilling fluid, you will not cool the liners properly — which will just make the situation worse. There is also usually a valve on the inlet of the spray bar. This valve should be closed enough so that liner wash fluid does not spray all over the top of the pump and other components. Ensure that the water is spraying inside the liner and that any overspray is not traveling out of the pump onto the ground or onto the pony rod packing where it could be pulled into the gear end. If the fluid is spraying out of the cradle area and falling onto the ground, it won’t be long before your liner wash tank is empty. It only takes a minute without the cooling fluid being sprayed before the liners become scorched. You will then need to replace the pistons and liners, which is an avoidable costly repair. Make a point to check the liner wash fluid level several times a day.

Drilling fluid — whether pumping drilling mud, straight water or some combination of fluid — needs to be clean. Clean meaning free of solids. If you are recycling your fluid, make sure you are using a quality mud recycling system and check the solids content often throughout the day to make sure the system is doing its job. A quality mud system being run correctly should be able to keep your solids content down to one quarter of 1 percent or lower. When filling your mud recycling system, be sure to screen the fluid coming into the tanks. If it is a mud recycling system, simply make sure the fluid is going over the scalping shaker with screens in the shaker. If using some other type of tank, use an inline filter or some other method of filtering. Pumping out of creeks, rivers, lakes and ponds can introduce plenty of solids into your tanks if you are not filtering this fluid. When obtaining water out of a fire hydrant, there can be a lot of sand in the line, so don’t assume it’s clean and ensure it’s filtered before use.

Cavitation is a whole other detailed discussion, but all triplex pumps have a minimum amount of suction pressure that is required to run properly. Make sure this suction pressure is maintained at all times or your pump may cavitate. If you run a pump that is cavitating, it will shorten the life of all fluid end expendables and, in severe cases, can lead to gear end and fluid end destruction. If the pump is experiencing cavitation issues, the problem must be identified and corrected immediately.

The long and the short of it is to use clean drilling fluid and you will extend the life of your pumps expendables and downhole tooling, and keep up with your maintenance on the gear end of your pump. Avoid pump cavitation at all times. Taking a few minutes a day to inspect and maintain your pump can save you downtime and costly repair bills.

For the successful execution of your projects, it is important to find an appropriate company with a good track record. We help you in connecting with the top mud pump manufacturers and companies and get the best quotation.

The most widely used mud pumps across the industry are Triplex Reciprocating Pumps. Their application has gained immense popularity with time because they are 30% lighter than duplex reciprocating pumps with relatively less operational cost. Moreover, through these pumps the discharge of mud is smooth and they are capable of moving large volume of mud at higher pressure.

Yes. We help you find the best mud pumps irrespective of your location. We simplify your search by connecting you with top mud pump manufacturers and mud pump companies in your location, according to your budget and business requirement.

The most widely used mud pumps across the industry are Triplex Reciprocating Pumps. Their application has gained immense popularity with time because they are 30% lighter than duplex reciprocating pumps with relatively less operational cost. Moreover, through these pumps the discharge of mud is smooth and they are capable of moving large volume of mud at higher pressure.

The different parts of a mud pump are Housing itself, Liner with packing, Cover plus packing, Piston and piston rod, Suction valve and discharge valve with their seats, Stuffing box (only in double-acting pumps), Gland (only in double-acting pumps), and Pulsation dampener. A mud pump also includes mud pump liner, mud pump piston, modules, hydraulic seat pullers along with other parts.

The wearing parts of a mud pump should be checked frequently for repairing needs or replacement. The wearing parts include pump casing, bearings, impeller, piston, liner, etc. Advanced anti-wear measures should be taken up to enhance the service life of the wearing parts. This can effectively bring down the project costs and improve production efficiency.

AfghanistanAlbaniaAlgeriaAmerican SamoaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBoliviaBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCabo VerdeCambodiaCameroonCanadaCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos IslandsColombiaComorosCongoCongo, Democratic Republic of theCook IslandsCosta RicaCroatiaCubaCuraçaoCyprusCzechiaCôte d"IvoireDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEswatiniEthiopiaFalkland IslandsFaroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuamGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and McDonald IslandsHoly SeeHondurasHong KongHungaryIcelandIndiaIndonesiaIranIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People"s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People"s Democratic RepublicLatviaLebanonLesothoLiberiaLibyaLiechtensteinLithuaniaLuxembourgMacaoMadagascarMalawiMalaysiaMaldivesMaliMaltaMarshall IslandsMartiniqueMauritaniaMauritiusMayotteMexicoMicronesiaMoldovaMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorth MacedoniaNorthern Mariana IslandsNorwayOmanPakistanPalauPalestine, State ofPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalPuerto RicoQatarRomaniaRussian FederationRwandaRéunionSaint BarthélemySaint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint MartinSaint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint MaartenSlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwedenSwitzerlandSyria Arab RepublicTaiwanTajikistanTanzania, the United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkmenistanTurks and Caicos IslandsTuvaluTürkiyeUS Minor Outlying IslandsUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuelaViet NamVirgin Islands, BritishVirgin Islands, U.S.Wallis and FutunaWestern SaharaYemenZambiaZimbabweÅland Islands

I’ve run into several instances of insufficient suction stabilization on rigs where a “standpipe” is installed off the suction manifold. The thought behind this design was to create a gas-over-fluid column for the reciprocating pump and eliminate cavitation.

When the standpipe is installed on the suction manifold’s deadhead side, there’s little opportunity to get fluid into all the cylinders to prevent cavitation. Also, the reciprocating pump and charge pump are not isolated.

The suction stabilizer’s compressible feature is designed to absorb the negative energies and promote smooth fluid flow. As a result, pump isolation is achieved between the charge pump and the reciprocating pump.

The isolation eliminates pump chatter, and because the reciprocating pump’s negative energies never reach the charge pump, the pump’s expendable life is extended.

Investing in suction stabilizers will ensure your pumps operate consistently and efficiently. They can also prevent most challenges related to pressure surges or pulsations in the most difficult piping environments.

The drilling industry has roots dating back to the Han Dynasty in China. Improvements in rig power and equipment design have allowed for many advances in the way crude oil and natural gas are extracted from the ground. Diesel/electric oil drilling rigs can now drill wells more than 4 miles in depth. Drilling fluid, also called drilling mud, is used to help transfer the dirt or drill cuttings from the action of the drilling bit back to the surface for disposal. Drill cuttings can vary in shape and size depending on the formation or design of the drill bit used in the process.

Watch the video below to see how the EDDY Pump outperforms traditional pumps when it comes to high solids and high viscosity materials commonly found on oil rigs.

The fluid is charged into high-pressure mud pumps which pump the drilling mud down the drill string and out through the bit nozzles cleaning the hole and lubricating the drill bit so the bit can cut efficiently through the formation. The bit is cooled by the fluid and moves up the space between the pipe and the hole which is called the annulus. The fluid imparts a thin, tough layer on the inside of the hole to protect against fluid loss which can cause differential sticking.

The fluid rises through the blowout preventers and down the flowline to the shale shakers. Shale shakers are equipped with fine screens that separate drill cutting particles as fine as 50-74 microns. Table salt is around 100 microns, so these are fine cuttings that are deposited into the half-round or cuttings catch tank. The drilling fluid is further cleaned with the hydro-cyclones and centrifuges and is pumped back to the mixing area of the mud tanks where the process repeats.

The drill cuttings contain a layer of drilling fluid on the surface of the cuttings. As the size of the drill cuttings gets smaller the surface area expands exponentially which can cause rheological property problems with the fluid. The fluid will dehydrate and may become too thick or viscous to pump so solids control and dilution are important to the entire drilling process.

One of the most expensive and troubling issues with drilling operations is the handling, processing, and circulation of drilling mud along with disposing of the unwanted drill cuttings. The drilling cuttings deposited in the half round tank and are typically removed with an excavator that must move the contents of the waste bin or roll-off box. The excavators are usually rented for this duty and the equipment charges can range from $200-300/day. Add in the cost for the day and night manpower and the real cost for a single excavator can be as much as $1800/day.

Offshore drilling rigs follow a similar process in which the mud is loaded into empty drums and held on the oil platform. When a certain number of filled drums is met, the drums are then loaded onto barges or vessels which take the drilling mud to the shore to unload and dispose of.

Oil field drilling operations produce a tremendous volume of drill cuttings that need both removal and management. In most cases, the site managers also need to separate the cuttings from the drilling fluids so they can reuse the fluids. Storing the cuttings provides a free source of stable fill material for finished wells, while other companies choose to send them off to specialty landfills. Regardless of the final destination or use for the cuttings, drilling and dredging operations must have the right high solids slurry pumps to move them for transport, storage, or on-site processing. Exploring the differences in the various drilling fluids, cutting complications, and processing options will reveal why the EDDY Pump is the best fit for the job.

The Eddy Pump is designed to move slurry with solid content as high as 70-80 % depending on the material. This is an ideal application for pumping drill cuttings. Drill cuttings from the primary shakers are typically 50% solids and 50% liquids. The Eddy Pump moves these fluids efficiently and because of the large volute chamber and the design of the geometric rotor, there is very little wear on the pump, ensuring long life and greatly reduced maintenance cost for the lifetime of the pump.

plumbed to sweep the bottom of the collection tank and the pump is recessed into a sump allowing for a relatively clean tank when the solids are removed. The Eddy Pump is sized to load a roll-off box in 10-12 minutes. The benefit is cuttings handling is quicker, easier, safer, and allows for pre-planning loading where the labor of the solids control technician is not monopolized by loading cuttings. Here, in the below image, we’re loading 4 waste roll-off bins which will allow the safe removal of cuttings without fear of the half-round catch tank running over.

Mud cleaning systems such as mud shaker pumps and bentonite slurry pumps move the material over screens and through dryers and centrifuges to retrieve even the finest bits of stone and silt. However, the pump operators must still get the raw slurry to the drill cuttings treatment area with a power main pump. Slurry pumps designed around the power of an Eddy current offer the best performance for transferring cuttings throughout a treatment system.

Options vary depending on whether the company plans to handle drill cuttings treatment on-site or transport the materials to a remote landfill or processing facility. If the plan is to deposit the cuttings in a landfill or a long-term storage container, it’s best to invest in a pump capable of depositing the material directly into transport vehicles. Most dredging operations rely on multiple expensive vacuum trucks, secondary pumps, and extra pieces of equipment.

Using an EDDY Pump will allow a project to eliminate the need for excavators/operators to load drill cuttings, substantially lowering both labor and heavy equipment costs. The EDDY Pump also allows a company to eliminate vacuum trucks once used for cleaning the mud system for displacing fluids. Since the pump transfers muds of all types at constant pressure and velocity throughout a system of practically any size, there’s little need for extra equipment for manual transfer or clean up on the dredge site.

The EDDY Pump can fill up a truck in only 10 minutes (compared to an hour) by using a mechanical means such as an excavator. For this reason, most companies can afford one piece of equipment that can replace half a dozen other units.

This application for the Eddy Pump has the potential to revolutionize the drilling industry. Moving the excavator out of the “back yard” (the area behind the rig from the living quarters) will make cuttings handling a breeze. Trucking can be easier scheduled during daylight hours saving on overtime and incidences of fatigued driving. Rig-site forklifts can move the roll-off boxes out of the staging area and into the pump loading area. The operator can save money on excavators rental, damages, and keep the technician operating the solids control equipment.

The EDDY Pump is ideal for drilling mud pump applications and can be connected directly onto the drilling rigs to pump the drilling mud at distances over a mile for disposal. This eliminates the need for costly vacuum trucks and also the manpower needed to mechanically move the drilling mud. The reasons why the EDDY Pump is capable of moving the drilling mud is due to the hydrodynamic principle that the pump creates, which is similar to the EDDY current of a tornado. This tornado motion allows for the higher viscosity and specific gravity pumping ability. This along with the large tolerance between the volute and the rotor allows for large objects like rock cuttings to pass through the pump without obstruction. The large tolerance of the EDDY Pump also enables the pump to last many times longer than centrifugal pumps without the need for extended downtime or replacement parts. The EDDY Pump is the lowest total life cycle pump on the market.

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