THE MUST-HAVE HANDBOOK FOR CENTRIFUGAL PUMPS

2y ago
41 Views
3 Downloads
3.44 MB
24 Pages
Last View : Today
Last Download : 2m ago
Upload by : Nixon Dill
Transcription

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SContent InsideCentrifugal Pump OverviewA brief overview of the centrifugal pump’s basic anatomy, and how a centrifugalpump works.Centrifugal Pump TypesLearn the characteristics, advantages, and disadvantages of 8 of the most used centrifugal pump typesCentrifugal Pump TerminologyDefinitions of a few terms about centrifugal pumps used in this book.About the AuthorsThis comprehensive guide was a collecitve effort among manyengineers and account managers at Crane Engineering. Thosecontributing include: Brad Parkhurst, Mike Gorges, RickOgle, Andrew Seltzer, and Kyle Pfaffendorf.Page 2

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SAn overview of centrifugal pumps.Centrifugal pumps are a very broad category of pumps. They vary so much in size,capacity, and abilities that it can be difficult to understand which is right for your application. This guide is designed to help you get a very basic understanding of the bestapplications, advantages, and disadvantages of different centrifugal pumps we help ourcustomers with every day.Before we dive into the different types available to you, let’s get back to basics and understand what characterizes a centrifugal pump, and how it really works.How It WorksCentrifugal pumps move fluid by using centrifugal force to generate velocity of the liquid. Fluid enters the pump through the suction nozzle, into the eye of the impeller. ThePage 3

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P Simpeller vanes catch the fluid and rotate itAdvantagesboth tangentially and radially until it exitsCentrifugal pumps are great for movingthe pump on the discharge side. The fluida lot of low viscosity fluid at fast speeds.leaves under a greater pressure than whenWith such a wide variety of options, it isit entered.not hard to find a centrifugal pump for justBest Applicationsabout any application.Centrifugal pumps work best with waterDisadvantagesand other low viscosity fluids. Efficiency isCentrifugal pumps can be sensitive to op-reduced when pumping viscous fluids.erating conditions. Vibrations, unbalance,They have a greater tolerance for solidsthan positive displacement pumps, someare built specially to handle large solids,up to 3” in diameter.and cavitation are just some of the factorsthat can cause a pump to literally self destruct. We wrote an eBook that covers this(36 Ways To Kill Your Pump).Pump AnatomyCentrifugal pumps come with their ownterminology. Review the section at the endof this book for some common terms associated with this type of pump, then takea look at the diagram on the next page forthe basic anatomy of a centrifugal pump.Page 4

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SThe Anatomy of aCentrifugal PumpShaftDischarge NozzleStuffing BoxSuction NozzleImpeller VaneEye ofImpellerImpellerCasingPage 5

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SSingle Stage, End SuctionThe single stage, end suction centrifugalpump is the most common type of centrifugal pump. It has a single impeller stagewhich adds energy to fluid as it rotatesinside the volute casing.Fluid enters the pump through a suctionnozzle at the end opposite of the drive (motor & bearing frame) and is redirected (at aright angle) to the discharge nozzle whereit leaves the pump at an elevated pressure.The amount of flow and pressure discharged depends upon a number of factors: Size of suction and discharge nozzles Diameter of the impeller Speed (RPM) of the pumpImpeller DesignsThere are a couple of impeller options.Open vane designs have a close clearance between the vanes and the pumpvolute or wear plate, preventing most ofGoulds Single Stage, End SuctionProcess PumpPage 6

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P Sthe fluid from recirculating back to theeye of the impeller. Closed vane impellershave the vanes shrouded on both sides.This “closed” design utilizes wear rings torestrict the amount of fluid that recirculatesback to the suction side of the impeller.SealingFluid must be restricted between the impeller and drive utilizing some type of shaftsealing device such as packing, mechanical seal, or magnetic drive.Best ApplicationsThe single stage, end suction pump is usedin a wide range of services in all industries requiring the transfer of fluids. Thesepumps should be the first considerationwhen pumping relatively low viscosity (approximately 500 cps or less) fluids.AdvantagesA multitude of sizes materials, sealing ar-Examples of open vane impellers.rangements and drive configurations areavailable to customize design for the mostreliable and efficient transfer of liquid.DisadvantagesThese types of pumps must be properlysized, applied, and installed or reliabilityand efficiency are compromised.Page 7

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SHorizontal Split CaseHorizontally split case pumps are characterized by the ability to remove the uppercasing for easier inspection, maintenance,or removal of the rotating element, withoutdisturbing piping or alignment.They sometimes include multiple impellers,or stages, to generate higher head. Theshaft supporting the impellers is supportedon both ends to provide balance.Goulds Split Case PumpThe impellers on the horizontal split caseare closed impellers. The double suctionvariety will have two opposing impellereyes, each receiving half the flow. Thesetwo impellers balance axial thrust.Best ApplicationsThe horizontal split case pump is great fora wide range of applications that requirehigh capacities and high head. Applications include: Practically any relatively clear processliquid Abrasive applications (with harderwear parts)inleteyeinlet eye Cooling tower service Boiler serviceInside of a double suction split case pump. Arrowspoint to inlet eyes on the impellers.Page 8

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SAdvantagesOne of the best advantages of the horizontal split case pump is that they can bemaintained and serviced without disturbingpiping and alignment. Simply removing theupper half casing gives access to the rotating element.This pump also has little issue with shaftdeflection due to its “between the bearing”design.This type of pump is known to be highly efficient because power is not lost to balancethe hydraulic thrust.The horizontal split case can move largeamounts of fluid, generating a great dealof flow and head.Rotating element with opposing closed impellers.DisadvantagesDouble the seals, means double the chancefor seal failures, and double the price formaintenance on those seals. Not only that,but the initial cost of these pumps is higher,especially if stainless steel or special alloysare needed.Though being able to access the internalsthrough removing the upper casing is convenient, depending upon its size, removingthe upper casing may require a crane andoverhead space.Rebuilt split case pump from a paper mill.Page 9

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SSelf Priming PumpsDisadvantagesA self priming centrifugal pump is made toInefficiency is a major disadvantage tolift water from some level below the pumpself-priming pumps, as clearances oftenelevation without having to fill the suctionneed to be larger to allow for better solidspiping with liquid. Air is removed fromhandling. Another disadvantage comparedthe suction line when the pump createsto the submersible, is that the pump is outa partial vacuum at the pump’s suction.of the pit, taking up floor space. Adding V-The pump then releases this entrained airBelt motors can take up even more space.through its discharge or a release valve.Best ApplicationsSelf priming pumps can handle a varietyof fluidsU M P SVertical Multi-Stage PumpsA vertical multi-stage pump has multipleliquid chambers (stages) that are connectedin series. Fluid enters the first chamber atsuction line pressure and leaves at someelevated pressure. Upon leaving the firststage, the fluid enters the second stagewhere the pressure is increased further.The more stages the pump has, the higherthe final discharge pressure. These pumpshave the unique ability to produce higherand higher pressures with the addition ofevery stage, but flow range always remains constant for a given rpm.Goulds Water Technology e-SVVertical Multi-Stage pumpPage 14

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SBest ApplicationsBecause the clearances in these pumps issmall, clean water applications are best forthis type of pump. High pressure shower systems Boiler feedwater Desuperheater feedAdvantagesThe vertical multi-stage is particularly adventageous for areas that don’t have muchfootprint to spare. Its ability to deliver highpressure output with a single pump bodyand motor combo is also a plus.DisadvantagesThis pump does not tolerate debris or significant solids, and is also vulnerable todeadhead conditions.It usually requires a higher rpm motor,therefore not always the highest efficiencypump.An inside look at the multiple stages inside.Page 15

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SSubmersible PumpsA submersible pump is design toBest Applicationsoperate with both pump body and motorSubmersible pumps work best in eithersubmerged in the fluid being pumped.clean water or waste water applicationsThe pump can be submerged due to thewhere the depth of the liquid level prohib-motor being hermetically sealed andits the use of a standard centrifugal pump.close-coupled to the pump end. A singleThey also are great for applications whereor double mechanical seal is utilized inspace is limited for above grade pumpsubmersible pumps to prevent the fluidinstallations. In wet well applications, thesebeing pumped from coming in contact withtypes of pumps eliminate the need for athe motor.dry vault next to the wet well.ABSSubmersible PumpsPage 16

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SAdvantagesBecause the pump is placed below thewaterline, the need for priming the pump iseliminated, and noise level is reduced.These types of pumps are also more efficient than above grade self-priming pumpinstallations due to pump design.DisadvantagesTroubleshooting a submersible pump canbe difficult as the pump is submergedwhen in operation. Also, mechanical sealor cable failure can lead to moisture in themotor housing.A look at the inner workings of a submersiblepump.Page 17

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SDry-Pit Submersible PumpsDry-pit submersible pumps are designedfor areas that are normally dry, but floodon occasion. A normal submersible pumpwould not work in this application becausewithout being submersed in water, the motor cannot stay cool. The dry-pit submersible pump, however, will often have themotor housing filled with a cooling oil. Incertain applications a cooling jacket willbe installed to prevent motor damagedcaused by excessive temperature.Best ApplicationsThese types of pumps are best placed inareas prone to flooding.AdvantagesResistant to flooding damage. Compact design (due to close coupled motor) is greatfor applications where space is limited.DisadvantagesMechanical seal failure can lead to moisture in the motor housing.ABS XFPSubmersible Sewage PumpsPage 18

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SVertical Turbine PumpsVertical turbine pumps are mostly used to pump water from deeppits or wells to some sort of water distribution system.This type of pump is comprised of a motor, discharge head, oneor more flanged columns to house the shaft, and one or morebowls (or stages). It’s also recommended that a basket strainer isinstalled on the last bowl to prevent large solids from entering thepump.Goulds Vertical Turbine PumpRebuilt discharge head and flanged columns (left) and bowl assembly (above).Page 19

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SBest ApplicationsVertical turbine pumps can be found in awide range of agricultural, municipal, andindustrial applications. They are generallymeant for clean water applications thatrequire high pressure and high head. Theyare most commonly used to pump out ofdeep pits or wells.AdvantagesVertical turbine pumps have a small footprint, and there are no priming issues dueto the impellers being submerged in fluid.They are easily customized, and are highlyefficient on high head, low flow applications.DisadvantagesThese types of pumps require a largeamount of headroom for installation andmaintenance. Hydraulic thrust is difficult tobalance on vertical turbine pumps due toLarge headroom is required for installation andmaintenance of vertical turbine pumps. The pumppictured is being removed to be rebuilt after 30years of service in a clean water application.their overhang design, especially in highsuction, high pressure applications.This type of pump can also experience issues with mechanical seals when pumpingfluids with entrained or dissolved gas. Thegas tends to accumulate at the top of thestuffing box or seal chamber, where venting is difficult.Page 20

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SSlurry PumpsSlurry pumps are heavy duty centrifugalpumps meant to pump abrasive and corrosive slurries. These types of pumpsare required to work under fluctuatingconditions, including ever-changing flow and solids content.The wet end components of these pumpsare designed to be thicker and lined with areplaceable rubber molding to extend lifein harsh conditions.Goulds PumpsXHD Slurry PumpBest ApplicationsDisadvantagesSome common slurry pump applicationsThe purchase price and operating costs ofinclude:slurry pumps are much higher than standard centrifugal pumps. They tend to pump Dirty water Water with solids Chemical slurries Ash slurry SludgeThough these pumps are built to withstandAdvantagesthe harshest pumping conditions, they stillSlurry pumps are constructed specificallyfor tough pumping applications and con-more slowly than water pumps, dependingupon the operating conditions (vibrations,pressure, axial thrust, etc.)require far more maintenance than pumpsin less demanding applications.tinuous operation.Page 21

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SCentrifugal PumpTerminologyCutwaterAxial & Radial Thrust - Refers to hydraulicand mechanical forces put on the shaft,causing movement of the shaft and impeller, and vibration throughout the pump.Cavitation - The formation of vapor bubblesin liquid, developed in areas where thepressure falls below the vapor pressure ofthe liquid. The imploding or collapsing ofthese bubbles as they move to higher pressure areas in the pump triggers intenseshockwaves inside the pump, causing sig-VoluteIllustration from Goulds GPM10, pg 889nificant damage to the impeller and/or thepump housing.Cutwater - Located near the discharge nozzle of the centrifugal pump, this part of thecasing helps to direct fluid out of the pump.Head - Simply put, head is the height at which a pump can raise a fluid up.Impeller - The rotating element on a centrifugal pump that tranfers energy from the motor,to the fluid inside the pump. Accelerates the fluid from the eye of the impeller outward towards the casing, and out the discharge nozzle. Comes in open, closed, and semi-openconfigurations.Page 22

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SPriming - The act of clearing air from the pump’s internals in order to function.Shaft - The shaft is the part of the pump that carries energy from the motor to the impellerinside the pump casing.Stuffing Box - The stuffing box houses a seal, or packing to help prevent leakage fromwhere the shaft enters the pump casing.Vane - Refers to impeller vanes that accelerate the fluid outward from the suction eye,and up to the discharge nozzle of the pump.Volute - The volute is the shape of the casing that surrounds the impeller. It’s volume increases in size towards the discharge nozzle. Its purpose is to keep velocity and pressure constant around the impeller, to stave off radial thrust on the impeller.Page 23

T H E M U S T- H AV E H A N D B O O K F O R C E N T R I F U G A L P U M P SConclusionThe centrifugal pumps included in this eBook are just some of the different types we runinto day to day. The array of centrifugal pumps in use today are beyond the spectrum ofwhat’s been listed here.When selecting a pump for your application, be sure to involve an engineer who is wellversed in all types of centrifugal pumps.Not sure which to choose? Ask us about it! We gladly provide technical assistance tobusinesses in Wisconsin and upper Michigan.Page 24

THE MUST-HAVE HANDBOOK FOR CENTRIFUGAL PUMPS Page 3 An overview of centrifugal pumps. Centrifugal pumps are a very broad category of pumps. They vary so much in size, capacity, and abilities that it can be difficult to understand which is right for your ap-plication. This guide is design

Related Documents:

May 02, 2018 · D. Program Evaluation ͟The organization has provided a description of the framework for how each program will be evaluated. The framework should include all the elements below: ͟The evaluation methods are cost-effective for the organization ͟Quantitative and qualitative data is being collected (at Basics tier, data collection must have begun)

Silat is a combative art of self-defense and survival rooted from Matay archipelago. It was traced at thé early of Langkasuka Kingdom (2nd century CE) till thé reign of Melaka (Malaysia) Sultanate era (13th century). Silat has now evolved to become part of social culture and tradition with thé appearance of a fine physical and spiritual .

On an exceptional basis, Member States may request UNESCO to provide thé candidates with access to thé platform so they can complète thé form by themselves. Thèse requests must be addressed to esd rize unesco. or by 15 A ril 2021 UNESCO will provide thé nomineewith accessto thé platform via their émail address.

Dr. Sunita Bharatwal** Dr. Pawan Garga*** Abstract Customer satisfaction is derived from thè functionalities and values, a product or Service can provide. The current study aims to segregate thè dimensions of ordine Service quality and gather insights on its impact on web shopping. The trends of purchases have

̶The leading indicator of employee engagement is based on the quality of the relationship between employee and supervisor Empower your managers! ̶Help them understand the impact on the organization ̶Share important changes, plan options, tasks, and deadlines ̶Provide key messages and talking points ̶Prepare them to answer employee questions

Bruksanvisning för bilstereo . Bruksanvisning for bilstereo . Instrukcja obsługi samochodowego odtwarzacza stereo . Operating Instructions for Car Stereo . 610-104 . SV . Bruksanvisning i original

Chính Văn.- Còn đức Thế tôn thì tuệ giác cực kỳ trong sạch 8: hiện hành bất nhị 9, đạt đến vô tướng 10, đứng vào chỗ đứng của các đức Thế tôn 11, thể hiện tính bình đẳng của các Ngài, đến chỗ không còn chướng ngại 12, giáo pháp không thể khuynh đảo, tâm thức không bị cản trở, cái được

10 tips och tricks för att lyckas med ert sap-projekt 20 SAPSANYTT 2/2015 De flesta projektledare känner säkert till Cobb’s paradox. Martin Cobb verkade som CIO för sekretariatet för Treasury Board of Canada 1995 då han ställde frågan