TESTING AND QUALITY

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Sulzer Pumps delivers pumps for demanding applications and, at the same time, continuously

improves the technology in order to be able to meet tomorrow’s customerchallenges. According to the testingrequirements of these two tasks, Sulzerruns test beds all over the world—eachdedicated to the needs of specificproducts and markets. Among these are the world’s largest installations

for full pump string testing at Leeds(UK)—with an installed drive power of 30 MW—and the recently openedlargest Sulzer Pumps factory in Suzhou (China) with a test bed featur-ing eight stations and a total powersupply of 15 MW. Key to the success ofSulzer is its capability to fully test everypump prior to shipping to ensure performance and problem-free commis-sioning.

Adapted test installationIn Sulzer’s competence center for processpumps in Kotka (Finland), the test loopis set up to allow the rapid testing ofend suction pumps of all sizes for thepulp and paper, food, metal, andfertilizer industries, as well as desalina-tion processes. The relatively high pro-duction volume of the process pumprange requires adapted installations. Inorder to deliver thousands of pumps per

Innovation through testing—test facilities that support product development

Proven qualityContinuous innovation requires state-of-the-art tools and equipment. Though numerical flowsimulation (computational fluid dynamics, CFD) has evolved tremendously over recent years, it is the correct correlation of CFD prediction and real fluid testing that enables the develop -ment of pumps that fulfill the most stringent needs of clients and industry. Sulzer Pumpstherefore operates test beds for both product development and final design validation.

1 Kotka (Finland)research center.

TESTING AND QUALITY

year, the test setup needs to be standard-ized with a high turnover. The requiredrapid setup and breakdown is achievedwith modular pump interface pipingthat can be quickly rotated into positionusing custom-built rotating assembliesholding the required range of suctionand discharge pipe sizes. At the factories there are test beds for

each pump type with multiple test bedsfor different sizes. Apart from a generaltest station for vertical pumps, processpumps, and multistage pumps withpower up to 500 kW, the newest andlargest operation test bed of SulzerProcess Pumps is the test station for largeprocess pumps. In this test bed, mea -surements can be carried out with highflow together with low pressure on thesuction side. Such tests with pressuresclose to the vapor pressure in the suctionpipe in combination with high flow ratesare very important in the design phaseof high specific speed pumps. One useof this low-pressure test rig is the simu-lation of pumping conditions in largeevaporators.

Energy efficiency Very similar test beds are available in the product development test bed in the Kotka research center 1. Themedium-consistency pulp pump loop—with power up to 600 kW, flow rates upto 1200 l/s, and pressures up to 25 bar—conforms to the requirements of the pulp

and paper industry. In this loop, theusual test materials are multiphase sus-pensions with gas, most commonly amixture of water, pulp fibers, and air.To optimize the energy efficiency of

the tests, equipment for energy recoverywill be installed in the multistage pumploop in Finland 2. A Pelton turbine con-nected to the same shaft train as motorand pump will recover the high pressurecreated by the pump. This setup willallow testing of multistage pumps at2.7 MW power while taking only 1.4 MWfrom the grid. At optimum conditions,only one quarter of the pump energy istaken from the grid. At the same time,the turbine reduces pressure with highefficiency and with much lower noiseemission than when dissipating—andthus losing—the energy in the valves. The hydraulics group in Finland has

optimized both the energy efficiency ofthe new multistage pump for reverseosmosis and of the associated test bed.This test bed will be used to validate thehydraulic and mechanical improvementsto the existing multistage pump rangeand to develop new pump sizes. Needlevalves with electric actuators control theturbine of the energy recovery system,which means the test loop operatorusing a Pelton turbine will see no differ-ence in the loop operating philosophy.A test series for a pump with a drivepower requirement of 1.4 MW will becarried out with just 400 kW of loss.

Comparisons with a traditional testsetup shows that the test rig will save8000 kWh of electric power in a singleday. As a usual test series for one pumphydraulic takes about 20 days, with thenew energy saving test rig, the environ-mental benefits and cost savings are significant.

Testing before deliveryIn addition to aiding the developmentof new products, testing also ensures thequality of the output. All pumps leavingthe production plant of Sulzer in Leedsare fully tested to both international stan-dards and customer-specific require-ments. On this test bed, highly engineeredpumps and packages (including thecontract driver) for the upstream oil andgas industry are tested before deliveryto site. This enormous facility is equipped

with the required systems to test pumpsdriven by gas turbines of up to 30 MW,large diesel engines, and high-voltageelectric motors. Recent modifications to the power grid gave Sulzer in the UK access to 45 MW of electrical powerand two in-house variable-speed drives(VSD). The test bed provides sufficientspace to install multiple skids, includingpump and driver, and, if required, thecontract VSD plus all of the supportequipment, such as mechanical seal andlubrication systems.

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3With seven singular test loops, the test bed in Oberwinterthuris highly flexible.

2 Energy recovery system.

This ability to rapidly test largeamounts of equipment shows thefacility’s testing flexibility and highlightsthe knowledge base available at SulzerPumps. These tests ensure that allsystems are working in synergy beforetheir arrival on site, thus removingpotential delays to the site’s commission-ing program.

Testing validates CFD design In Oberwinterthur (Switzerland), SulzerPumps operates a dedicated test bed,which supports product development,large contract-related developmentprojects, and fundamental research 3 .

This development test bed is part of thedevelopment process for new productsor pump ranges as well as of speciallarge engineered pumps. The hydraulicsgroup in Switzerland has significantlycontributed to the design of new pumpranges with a greenfield approach. Forexample, the model testing in Winterthurverified the CFD analysis and hydraulicdesign of pumps developed for a newpipeline in Eastern Asia. The main goal of the development test

bed is the validation of all characteristicsof a newly developed hydraulic beforeit is used in a new pump design. Forthis purpose, the validation tests areexecuted on scaled model pumpsproduced in aluminum using rapid pro-totyping (mainly NC machining) 4. Thetest bed features seven small-to-mediumsize loops that are designed to allowhigh flexibility in terms of the type ofpumps that can be tested—with oneloop devoted to two-phase testing forthe development of the Sulzer multiphasepumps. During these development tests, all

standard pump characteristics, such asflow, head, power, efficiency, and netpositive suction head (NPSH) arerecorded. NPSH is an important valuerelating to cavitation behavior of thepumps; it describes the differencebetween the actual pressure of a liquidand its vapor pressure at a given tem-perature. Additionally, all relevant infor-mation is measured that may be neededfor the final design of a pump or in orderto ensure its proper behavior under siteconditions. These additional tests include:• internal pressure measurements inorder to identify the losses in the dif-ferent hydraulic components

• radial- and axial-static and -dynamicload measurements

• pressure pulsation measurement atsuction and discharge

• visualization of cavitation bubbles onthe suction side and occasionally onthe pressure side of the vanes

• measurement of pressures, vibrations,or stresses in the rotating parts of thepump, i.e., within the impellers invery special cases

Research on the impact of surfaceroughnessFor the development of high-perfor-mance pumps, both advanced CFD andhigh-accuracy measurement are needed;these involve specialized tools andhighly trained personnel. Sulzer Pumpshas invested heavily into both to ensurecontinuing success and has used thetest results to validate CFD data formany years. Due to these efforts, theSulzer experts know the applicationlimits of CFD for the design of pumphydraulics. Within these limits, designcorrelations linking CFD results andgeometric design parameters give essen-tial support during the design of newhydraulic contours. Modern research requires the interac-

tion of measurements and CFD calcu-lations in order to improve the accuracyof the design process. Currently, Sulzerspecialists are particularly engaged inexamining the use of CFD calculationsin predicting the influence of surfaceroughness on pump performance. Inorder to calibrate the various modelsfor surface roughness in the CFD codes,the developers need surface qualitymeasurements of the pump parts, mea -surements of their hydraulic per -formance, and CFD calculations, includ-ing manufacturing-quality models. In the Finnish R&D location, an exten-

sive test program for new multistagepump hydraulics and mechanics willstart in 2011. For this pump, everywetted surface has been calculated byCFD. Consequently, expected hydraulicperformance, leakage losses, and forcebalancing are based on CFD calculations.During these tests, the Sulzer engineersexpect to gain more in-depth knowledgeabout the validity of the applied CFDsurface roughness model.

Visualization of cavitationFor projects with demanding suctionperformance or where high-suctionenergy leads to a high risk of erosiondue to cavitation, Sulzer performsbubble tests on the test rig in Oberwin-terthur. These bubble tests are used toassess the extent of cavitation develop-

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TESTING AND QUALITY

4 Rapid prototypingusing NC machining

speeds up the manufacturing of the test components.

5 String test of a gas-turbine-driven pump at Sulzer facility in Leeds, UK.

TESTING AND QUALITY

ment as a function of suction pressureor NPSH. For this purpose, modelpumps are equipped with large windowsallowing visual access to the entire eyeof the suction impeller over 360°. SulzerPumps uses the high competencies ofSulzer Innotec in complex NC machiningfor the production of these modelpumps. These skills are needed to suc-cessfully machine the complex 3Dcontours of casings and impellers outof solid blocks of aluminum.The window at the suction side allows

the experimental confirmation of thesuction pressure at which the firstbubbles are visible on the vane surfaceat all positions of the impeller withinthe pump inlet casing. It also allows theidentification of the cavitation length fora given suction pressure and, conse-quently, the estimation of the accordingrisk of erosion.Because the pressure side of the vane

is not visible in the impeller eye if fullymetallic vanes are used, in order to alsoconfirm the cavitation development onthe pressure side of the vanes, one ortwo vanes of the development impellersare machined from acrylic glass. The esti-mation of cavitation is especially impor-tant for large injection pumps for thepetroleum industry or for large boilerfeed pumps for thermal power plantsfor which the suction energy and therisk of cavitation erosion may be veryhigh.

Focus on prototype performanceWhen a model pump is used in the devel-opment of new suction impellers forthese applications, it is designed at pro-totype scale. This procedure allows thejob impellers to be tested in order toconfirm cavitation-free operation on site.Because of the presence of a windowthat limits the suction pressure, as a com-promise, tests are performed at areduced speed compared with site con-ditions, and the full-speed performanceis calculated using standard affinitylaws.The development test bed is also used

to check the mechanical performance ofkey elements of pumps, such as bearingsor seals. For example, dedicated testingequipment has been developed in orderto test different material combinationsfor the product-lubricated line shaftbearings under real site conditions usingwater charged with sand.

Prepared for future demandsSulzer Pumps continuously developsand improves the testing methods fornew products and for machines. Forexample, the demand for subseapumping is growing, along with therequirements that pumps operatingunder water have to fulfill. To be ableto test subsea processing equipmentunder realistic conditions, Sulzer isinvesting in a dedicated multiphase

subsea test bed in the UK. This state-of-the-art addition to the already impressivestring testing facilities in Leeds 5 willposition Sulzer as the market leader withrespect to pump-testing facilities. In thisinstallation, it will be possible toexamine subsea pump/motor packageswith weights approaching 100 tons inwater depths of up to 10 m 6. When deployed in the open ocean,

these pumps will operate in many kilo-meters of water depth and are designedto take high external and internal pres-sures whilst delivering the high pressurerises that customers require. The firstpump that will be tested once the testbed is commissioned will be a 3 MW,6000 rpm multiphase pump able todeliver over 100 bar pressure rise—wellsuited for many of the current subseaapplications. Current specifications and market

ideas set the standards for capabilitiesand capacity of any new test bed. Sulzer,however, follows the motto “designingfor the future” and requires that newtest installations must consider futurepossibilities for expansion. Sulzer therebyplans to keep these investments opera-tional and useful for many years, as bothproducts and markets mature and adapt.This philosophy makes it possible forSulzer Pumps to deliver pumps adaptedto market and client requirements nowand in future years.

Matt Bourne Sulzer Pumps (UK) Ltd.Manor Mill LaneLeeds, LS11 8BRUKPhone +44 113 272 5704matt.bourne@sulzer.com

Matti KoivikkoSulzer Pumps Finland OyP.O.Box 6648601 KotkaFinlandPhone +358 50 555 0268matti.koivikko@sulzer.com

Philippe DupontSulzer Pumps Ltd.Zürcherstrasse 128401 WinterthurSwitzerlandPhone +41 52 262 40 30philippe.dupont@sulzer.com

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6 Subsea test bed at Sulzer facility in Leeds, UK.