Vesconite and Vesconite Hilube

Pump BearingDesign Manual

Long life, low friction, no swell

www.vesconite.com

Contents PageFitting your pump summary examples ...............................2Superior pump bearing materials ...........................................3Why Vesconite and Vesconite Hilube are ideal for pump bearings.............................................................................4Vesconite and Vesconite Hilube fitted to your pump

Mixed flow turbine pumps ..........................................................8

Vertical spindle sump pumps....................................................10

Centrifugal pumps.....................................................................11

Archimedes screw pumps ........................................................12

Other pumps .............................................................................12

Technical designGrooving of bearings.................................................................13

Designing for dirty conditions ...................................................14

Dry running of pumps ...............................................................14

Securing pump bearings...........................................................15

Housings and shafts of bearings ..............................................16

Typical properties of Vesconite and Vesconite Hilube .....18Chemical resistance chart ......................................................18Bearing size calculations with worked examples .............20Machining tolerances..................................................................22Machining guidelines ...............................................................23Vesconite worldwide stocks ..................................................24What www.vesconite.com can do for you ..........................25Technical enquiry form and request for quotation

The development ofVesconite by VescoPlasticsbegan in 1968 in an attemptto find a plain bearingmaterial suitable for use inexceptionally harsh, dirty andwet conditions found in thesurrounding ultra deepmines.

Vesconite Hilube wasdeveloped later to enhancethe performance of standardVesconite.

Hitemp 150 was developedas a material resistant tohigher temperatures.

Today VescoPlastics is asupplier of low friction, longlife, low wear bearingmaterials, supplied to manyindustries in over 50countries worldwide.Industries include pumps,railways, mining, heavytransport, earthmoving andmarine.

VescoPlastics consists of adedicated manufacturingplant including extrusion andinjection moulding facilitiesas well as a well equippedmachine shop experienced in

machining Vesconite tofinished bearing sizes andtolerances. Manufacturingprocesses are controlled bystrict quality standards thatensure products that areconsistent in properties andsize.

VescoPlastics has manyyears experience of bearingapplications in many criticalindustries and is able toadvise customers on specificapplication requirements.

VescoPlastics company profile

Vesconite pump components

1

Vesconite Hilube bearings

Vesconite and Vesconite Hilubesupport and lineshaft bearings

Vesconite Hilube stuffing box bearing

with lantern ring

Vesconitelantern

restrictors

Hitemp 150 pump bowl bearing

with lantern ring

Hitemp 150 split bearing

Vesconite andVesconite Hilube

wear rings

2Fitting your pump Summary examples

Vesconite and Vesconite Hilube offer significant advantages ina number of pump applications.

Vertical spindleturbine pumps

Top stuffing box bearings Vesconite Hilube is ideal for dry start up conditions

Closer running clearance means reduced seal wear

Lineshaft and pump bowl bearings Long life

Can be lubricated with process water as well as oil

Vesconite Hilube able to survive dry running conditions

Closer running clearance means less shaft run out andvibration

Suction cover bearings Good wear life even in dirty conditions

Can be lubricated with process water rather than dedicatedgrease or oil supply

Vertical spindlesump pumps

Shaft support bearings Can be lubricated with water or process fluids as well as

grease or oil

Able to survive temporary suspension of lubrication duringstart up or pump snoring

Impeller support bearings Close running clearances

Low wear

Can run dry

Wear rings Close running clearances improve pump efficiency

Centrifugal pumps Support bearings Low wear rate

Closer clearances give a stable shaft and lower seal wear

Lantern rings Low friction gives ability to survive temporary suspension of

lubrication water

Dimensional stability allows for closely defined clearancesto regulate water flow

Impeller and casing wear rings Low friction and low water swell allows smaller running

clearances giving better pump efficiency

3What is Vesconite?Vesconite and VesconiteHilube are specialized plainbearing materials made frominternally lubricated lowfriction polymers. Vesconite

bearings give excellent wearin harsh, wet, dirty orunlubricated conditions.

Vesconite and VesconiteHilube have manyadvantages over traditional

bearing materials such asbronze, acetal, nylons(whether plain or internallylubricated), nitriles, rubbers,elastomers, phenolics andlaminates.

Vesconite low friction, long life, well proven

The internally lubricated long life bearing materialthat has been proven in thousands of critical

applications. Originally developed to overcomebearing problems caused by water swell of traditional

non-metallic bearing materials.

Vesconite Hilube lowest friction, longest wear life, lowest shaft wear The advanced grade of Vesconite witha lower friction, lower wear rate anda greater ability to run dry.

Vesconite Hilube has the samedimensional stability, mechanicalproperties and chemicalresistance as Vesconite.

Hitemp 150 high temperature, abrasion resistant

A low wear bearing material specially formulated forhigher temperature resistance, Hitemp 150 can run at

elevated temperatures up to 150C (300F).

Hitemp 150 also has exceptional abrasion resistance and iswell suited to pump applications of media with suspended

dirt particles.

Hitemp 150 may be the material of choice when corroded orrough shafts cannot be avoided.

4Resista

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Negligib

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High c

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Low sha

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Easy to

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and re

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Easy to

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Safety

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Why Vesconite and Vesconite Hilube are ideal for pump bearings

Low friction Vesconite is compoundedwith internal lubricants toproduce a material with a lowcoefficient of friction. Thislow friction is maintainedeven when lubrication orwater is not present.

Vesconites low frictionapplies not only underlaboratory test conditions,but also under actualoperating conditions. Stick-slip does not occur withVesconite bearings even ifpumps have been in standbymode for long periods of time

without operating. This canreduce the requirement toprime bearings beforestarting a pump. This iscritically important foremergency type pumps suchas fire pumps, settler pumpsand flood pumps.

Able to run dryPump bearings often need towithstand dry running forshort intervals, for example atstart up or if the pump inletbecomes blocked. Vesconiteand Vesconite Hilubes

internal lubricants give thema very low friction even whenlubrication is not present.

Vesconite can surviveoperating conditions wherelubrication is delayed orintermittent without

damaging the bearing. Manybearing materials operatewell under well lubricatedsituations, but fail whenlubrication is not present.

Negligible water swell Vesconite does not swell orsoften in water, whereasmost synthetic materialsswell in water. Vesconitebearings can be machinedaccurately to size andmaintain these sizes evenwhen immersed.

To compensate for the waterswell and to avoid the risk ofseizures, excessiveclearances are used. WithVesconite, close clearancescan be maintained, reducingvibration and shaft run out.Large clearances should beavoided because:

Bearing wear rate increases Bearing life is shortened Shaft vibration increases,

making the shaft less stable.

Percentagechange in size

Vesconite 0.03

Elastomer 1.25

Phenolic 0.5 to 2.01

Nylon 3.0

Swell of synthetic bearing materials due to water

5equipment. Bearings can beeasily installed on site with aminimum of effort andequipment, using simplemechanical methods.

Easy to install andremoveVesconite bearings are easyto install and remove withoutthe need for expensive

Vesconite does not corrodeand seize in bearinghousings, unlike bronze andmetal backed bearings whichbecome difficult to remove.

Easy to machine Vesconite can be easilymachined on standardmetalworking orwoodworking equipment.Vesconite does not creep,deform or swell andmachines easily to desiredtolerances.

High compressionstrength Vesconite keeps its strengtheven when wet and does notcreep under high loads.Loads on Vesconite bearingsdo not result in compression,deformation or compressionset. This means that the shaftis more stable.

High load capacity Vesconitebearings offer better loadcapacity than manytraditional rubber orelastomer bearings.

Low shaft wearWear of expensive shafts canbe more of a problem thanwear of a bearing because ofthe cost of the shaft. Shaftwear is especially severe in

dirty operating conditions.Appropriately designed hardshafts running in Vesconitebearings exhibit exceptionallylow wear. Vesconite Hilubefurther reduces shaft weardue to its lower friction. In

particular nylons and manyrubber materials are notedfor damage caused to shafts.

Drinking water approval Vesconite and VesconiteHilube have undergoneextensive testing and havebeen approved by anindependent water quality

authority for hot and colddrinking water applications.

Vesconite bearings can beused in continuous fullcontact drinking waterapplications.

12750

8500

4250

0

90

60

30

0

MPa Psi

Saturated compression strength

Vesconite Nylon Elastomer Rubber

Tip / insert

6Resistant to chemicals In addition to its excellentperformance in water,Vesconite and VesconiteHilube are resistant to a widerange of chemicals includingacids, organic chemicals,solvents, hydrocarbons, oilsand fuels. Page 18 gives adetailed chemical resistancechart.

Vesconite and VesconiteHilube bearings can thereforebe lubricated by a range ofpumped media. Mixtures ofwater, oils and fuels do notdamage Vesconite bearings.

Vesconite does not containany hazardous substancessuch as asbestos or fibresthat make using, handlingand machining unsafe.Vesconite is an exceptionally

clean material to machineand possesses no fibre ordust hazards.

Safety and health

Vesconite bearings do notchange size significantly as

This means that Vesconitebearings can be designedwith minimal runningclearances without danger ofshaft seizures.

Low thermal expansion

Environmental problemscaused by oil or greaselubrication can be avoided.This means simpler pumpdesign and operation, withgreat cost savings.

The good chemicalresistance of Vesconite andVesconite Hilube means thata large range of pumpedmedia can be used tolubricate the bearings.

Environmentally friendly

Delamination is the peelingoff of layers of a laminatedbearing material. This oftenhappens in immersedconditions where water orliquid penetrates the exposedmicro-channels that areformed by the clothreinforcing material. Swellingoccurs along the micro

No delamination channel surfaces causingstresses between the layersof the laminate, resulting inthe layers peeling off.

Vesconite is a homogeneousmaterial with no laminationreinforcement and so doesnot delaminate.

the operating temperaturechanges, so close clearancescan be maintained across awide temperature range.

7Vesconite andVesconite Hilubefitted to your pumpThere are many pumpdesigns, each with its ownunique demands for its areaof operation.

But all pump users requirereliable bearings and wearrings. Pumps are often usedin critical applications wherebearings failure must nothappen as the consequentialresults could be extremelyserious.

Vesconite bearings providethe performance, reliabilityand long life desired bypump manufacturers and endusers in a variety of pumpbearing applications.

8Vertical spindle,axial flow, mixedflow, turbine andpropellor pumpsThese pumps are generallyused to pump high volumesof water at low pressureheads, often in criticalapplications or as emergencystandby pumps wherereliability and long life areimportant. Maintenance onthese pumps can be difficultand expensive. Examplesinclude:

Power station coolingwater pumps

High volume fire fightingpumps

Top up water pumps Submersible bore hole

pumps

Waste water pumps River abstraction pumps

Stuffing box bearingsStuffing box bearings lack the water flow experienced bylineshaft bearings. Vesconite bearings offer a low friction andtherefore an ability to perform with only a limited water flow.

Vesconite Hilube bearings can survive a dry start up of thepump as well as giving a long bearing life in the absence oflubrication through the bearing.

Water flow through stuffing box bearings can be ensured usinga pressure feed line or a low pressure dump line. A lantern ringgroove can be added to the bearing to allow a well distributedflow across the bearing.

Vesconite bearings can be manufactured to close runningclearances which do not change considerably due totemperature variations. Nor will Vesconite swell so the dangerof shaft seizure is avoided.

Because of the closer running clearance, the shaft is morestable. Greater shaft stability and less vibration means thatseals and external roller bearings are able to operate moreeffectively and last longer.

Lineshaft and pump bowl bearingsMany bearing materials operate adequately when a good waterflow is present through the bearing. This flow is not alwayspresent on start up or can be interrupted due to a blocked inletto the pump. This situation is a problem to bearing materialsthat require an uninterrupted water flow.

The dry running ability of Vesconite allows bearings to survivethese conditions with no permanent damage. Vesconite andVesconite Hilube are internally lubricated with advancedlubricants that give them the ability to withstand a temporarysuspension of water lubrication.

Vesconite allows for high precision, long life and reliableproduct or external feed lubricated bearings.

Vesconite bearings can be lubricated with water or a range ofpumped product which limits the requirement for cumbersomeoil lubrication systems and the environmental hazardassociated with these systems.

Vesconite can be lubricated with oil in the case of oil lubricatedpumps.

The internal lubrication and high strength of Vesconite allowsfewer or shorter bearings to be used.

Closer running clearances ensure more stable shaft operationwith less vibration.

9Suction cover bearingsSuction cover bearings usuallyexperience high concentrations ofdirt particles from the water sourceespecially in river water applications.To overcome wear caused by thisdirt, suction cover bearings are oftensealed and grease or oil lubricated.Grease or oil may be fed from thesurface through long lubrication linesalong the length of the pump.

In addition to the complex grease oroil lines and the required lubricationsystem, a big disadvantage is thatany grease or oil leaking from thebearing contaminates the processwater.

Vesconite can be lubricated withprocess water fed from an upperstage rather than from a dedicatedoil or water lubrication system fromthe surface. Often cumbersomegrease lubrication lines and systemscan be done away with and greasepollution avoided.

Where suction cover bearings arewater lubricated, the upstream sideof the bearing is sealed to preventdirty water from entering the bearing.Water is fed either from an upperstage or from a dedicated supplyinto the bearing usually using alantern ring groove in the bearing.The downstream side of the bearingis open and the water is exhaustedinto the pump flow.

Where a totally sealed bearing isrequired, Vesconite can belubricated with grease or oil.

Impeller and casing wear ringsVesconite can be used for efficientimpeller and casing wear rings. Dueto its self lubricating properties,Vesconite can run with a smallerrunning clearance than metal wearrings. Instantaneous contact with thecasing or impeller wear ring does notcause damage to the Vesconite or tothe mating surface.

The closer running clearance meansan efficiency improvement due to alower by-pass.

10

Vertical spindle sumppumpsSump pumps can be used to pumpa variety of fluids including clearwater, hot liquids, chemicallyaggressive fluids and to dirty andabrasive liquids with highconcentrations of particles or fibres.Examples include:

Sump drainage pumps Vertical cantilever slurry pumps

Intermediate shaft support bearingsWhen pump shafts are long, intermediate bearings arerequired to support the shaft. These bearings areoften lubricated by dedicated grease supply lines fromthe surface.

Vesconite shaft support bearings can be lubricatedusing a dedicated lubrication supply or process waterfed from the pump discharge pipe with no need foradditional lubrication systems.

Especially on long pumps that are used in a harshenvironment, lubrication lines are often broken off atinstallation or during operation.

Vesconite bearings can be designed with closerunning clearances. This means a more stable shaftand less shaft run out.

The self lubrication of Vesconite allows successfuloperation of the bearing even when the water flowfrom the discharge pipe is temporarily suspended.The dry running ability of Vesconite reduces the needto prime the pump before start up.

Impeller support bearingsImpeller support bearings are often fully exposed tothe harsh liquids that are being pumped. Thesebearings are immersed in the medium but lack theflow of lubrication often required by bearing materials.

Vesconite bearings can resist many chemically harshpumped media.

Where pump snoring occurs, Vesconites selflubrication allows the bearing to run for a time withoutdamage caused to the shaft or bearing by the lack oflubrication.

Close running clearances allow for stable impelleroperation with reduced vibration.

Where the pumped medium is especially dirty or hotand the bearings are not isolated from the media,Hitemp 150 is the material of choice. Hitemp 150 is amaterial designed for high temperature applicationswith the added advantage of good abrasionresistance.

Wear ringsVesconite wear rings can be designed with closerrunning clearances improving the pump efficiency dueto a lower bypass.

11

Centrifugal pumpsExamples include:

Multistage mining pumps Process pumps Slurry pumps In line process pumps Split case pumpsSome specific applicationsinclude:

Support bearings Lantern rings Impeller and

casing wearrings

Supportbearings

Impeller andcasing wearrings

Vertical in line pumpsSplit case pumps

Support bearingsVesconite bearings can be designed with close runningclearances reducing shaft vibration and improving externalbearing life.

Vesconite long life bearings ensure that expensive removal andrepair of pumps is limited.

Support bearings can be grooved bearings when there is awater flow through the bearing. Bearings may not requiregrooves where the bearing is immersed in the pumped mediumand does not require much cooling.

Lantern ringsLantern rings are used as part of a shaft sealing system toevenly distribute water around the pump shaft and are usedespecially in slurry pumps.

The dimensional stability of Vesconite allows for stable runningclearances so that a desired water flow rate may be achieved.Due to their low friction, Vesconite rings can survive even whenthe water supply is temporarily suspended.

Impeller and casing wear ringsVesconite wear rings can be designed to run with smallerclearances between the ring and impeller or casing. Thismeans a higher pumping efficiency due to a lower by-pass.

If the Vesconite wear ring happens to contact with the housingno damage is caused. The wear ring will conform to the newsize and re-establish a close clearance.

Overhung process pumps

Support bearings Impeller and casing wear

rings

12

Archimedes screws

Vane pumps, compressors and air motors

Water lubricated end support and intermediate bearings

Flushed Vesconite bearings perform well even in harshchemical or dirty environments. Vesconites high loadingcapacity coupled with low friction gives low wear rate bearings.

Vesconite can be flushed with water rather than lubricated withenvironmentally polluting oils and greases.

Bearings are usually grooved to ensure an adequate flow ofwater through the bearing.

Vesconite vanes showedgood wear life in manyapplications, are not easilydamaged or cracked likecarbon vanes and areresistant to a variety ofpumped media.

Gear pumps

Pump bodies and gearsThe dimensional stability, good resistance to a variety ofchemicals and low wear rate make Vesconite well suited topump bodies and pump gears

Support bearingsThe low friction, long life properties of Vesconite give a long lifefor support bearings.

The low friction of Vesconite Hilube allows successful operationeven when running dry for a short time.

Other immersed applicationsAerators, thickeners, mixers, hydroelectric turbines and flowgates all benefit from using Vesconite bearings.

Vesconite does not swell in water and therefore can maintainclose running clearances without the danger of seizure in manyimmersed applications.

Vesconite has a very low wear rate especially when lubricatedwith water. This reduces maintenance on many of these difficultto maintain applications.

External gear pumps

Internal gear pumps

13

Technical DesignCorrect bearing design isessential to long life bearingoperation. Different bearing

materials have differentcriteria for design. Vesconiteand Vesconite Hilube aresuperior bearing materials.However, if these materials

are designed incorrectly,premature bearing failuremay occur.

Grooving of bearingsMany pump bearings requireeffective cooling of the

bearing surface because ofthe frictional heat generatedby high rotational speeds.Pump bearings often require

cooling by either processfluids or dedicated lubricationsystems through correctlydesigned grooves.

Straight, axial orlongitudinal grooves

Generally straight grooves areused for lineshaft bearings onvertical turbine pumps. Thepumped medium passesthrough the axial grooves toprovide a constantlyrefreshing cooling film.

It is important that thesebearings are not greased asthe grease may block thechannels. This will limit thewater flow through thebearing, possibly leading tooverheating of the bearing.

Typical groove design for straight grooves

Shaft diameter No. of Size - mm Size - inches Water flow ratemm inches grooves width depth width depth l/min-1 gal/min-1

20-30 1 11/2 3 6 2.5 0.25 0.1 4 1.0

31-50 11/2 2 4 8 3 0.30 0.125 8 2.0

51-80 2 3 6 8 3 0.30 0.125 12 3.0

81-120 3 5 6 10 3.5 0.40 0.15 18 4.5

121-160 5 7 8 12 4 0.50 0.20 24 6.0

161-200 7 8 10 12 4 0.50 0.20 30 8.0

Spiral grooves Spiral grooves can be usedas an alternative to straightgrooves. They can be usedon slower moving shafts orwhere the bearing isimmersed in the pumpedproduct. A similar numberand size of grooves as noted

in the above table for straightgrooves needs to be used forspiral grooves.

Straight grooves are usuallyrecommended for pumpbearing applications.

Groove shape and depth Grooves should preferably begreater than 2.5 mm (0.1)deep to avoid blockages bysand or coarse debris. As ageneral rule the depth ofgrooves should be less thanhalf the wall thickness of theVesconite bearing.

When a thin wall thicknesslimits groove depth, extragrooves can be added toensure adequate flow.Round grooves

UV or square grooves

14

Wall thicknessIt is generally recommendedthat the wall thickness shouldbe greater than 5% of thehousing diameter.

For thinner Vesconitebearings, care will berequired when machining orfitting to avoid cracking.Bonding and mechanicalsecuring can be used toensure that the bearing isproperly secured.

Designing for dirtyconditionsSuspended dirt particlessignificantly increase wear ofall bearing materials andcause wear to expensiveshafts. This is a commonproblem especially on pumpsuction cover bearings whenpumping dirty river orprocess water.

To overcome this problem,suction cover bearings areoften sealed and lubricatedwith grease or oil from adedicated supply. But thisadditional system iscumbersome and is prone todamage especially duringpump installation or removal.It may cause environmentalproblems, especially if thereis an oil leak.

In dirty conditions, Vesconitecan be lubricated with:i) Process water, thus

dispensing with greaseand oil lubricationsystems. This is achieved

using a feed from an upperstage when using a multi-stage vertical spindleturbine pump.

ii) Clean water feed. This isadvised when the pumpedmedium is very dirty.Water fed Vesconitebearings are usually sealedat the upstream side andopen at the downstreamside. Water (process wateror a dedicated supply) isfed into the bearing oftenusing a lantern ring, andafter flowing through thebearing it is exhausted intothe pump flow.

iii) Grease or oil. Vesconiteperforms well with oil orgrease lubrication.In dirty conditions,Vesconite Hilube bearingsare preferred as they give alow wear rate and muchreduced shaft wear,especially when runningagainst suitably hardenedshafts.

Traditional bearing materialsoperate acceptably as longas this cooling flow ispresent. This flow can easilybe interrupted during startup conditions or due toblocked inlets, causingbearing damage or evenleading to failure and pumpdowntime.

Vesconite is internallylubricated giving a lowfriction which allows thebearing to cope with highloads and speeds.

The internal lubricant ofVesconite Hilube gives a verylow friction and a greaterability to deal with theseconditions.

At start up, typical verticalspindle pumps may requirethe upper lineshaft bearingsand the stuffing box bearingto run dry for a time beforewater reaches the bearing.

Dry start and running ofpump bearingsPump bearings generallyrequire a lubrication film toremove the heat resultingfrom the high sliding speedsand bearing loading. Water orother pumped media isdrawn through the groovesand over the bearing surfaceto provide effective cooling.

The bearings can be primedbefore start up, but this isoften neither easy norconvenient to achieve.

Tests have been conductedon Vesconite Hilube bearingsto determine their ability torun dry under typical pumpoperating conditions.Vesconite Hilube survived forwell over one minute withoutbearing damage.

This is far better thanalternative water lubricatedpump bearing materials,many of which melt down orburn within seconds. Ninetypercent of dry start upspecifications require onlyone minute dry running time.

Pumps operating withVesconite or Vesconite Hilubedo not require pre-lubricationof the bearings and can rundry for a time without thedanger of bearing damage.

wall thickness

housing diameter

15

Interference fitsUsing an interference fit isthe easiest method to securea Vesconite bearing when thebearing operates attemperatures up to 70C(160F).

Vesconite is a rigid materialand may be easily securedwith an interference fitwithout the need foradditional methods. Thebearing can easily beinstalled and removed usingsimple mechanical methods.

Securing pump bearings

Diameter Chamfer @ 30mm inches mm inches

10 20 1/2 1 0.5 0.02

20 50 11/2 2 1 0.04

50 100 2 4 1.5 0.06

100 250 4 10 2 0.1

>250 > 10 3 0.15

Freeze fittingFreeze fitting greatly helps withinstallation of long bearings(length greater than the shaftdiameter), large bearings andbearings with thin walls.

This can be done using acold freezer (-40C, -40Fpreferably) or with dry ice.

When using dry ice, pack thebearing on the inside andoutside with dry ice in aninsulated container. Thebearing will shrink to less thanthe housing diameter whichallows for an easy slide fit.

Liquid nitrogen can be used.Take great care to ensurethat the bearing does not

come into direct contact withthe liquid nitrogen. Place thebearing on wooden blocks inan appropriately insulatedcontainer. Pour some liquidnitrogen into the bottom ofthe container to below thelevel of the bearing and allow

to cool. Vesconite should notbe immersed in liquidnitrogen.

Do NOT heat the bearinghousing to aid installation asthis may damage theVesconite bearing.

Fitting bearings Fitting and removal of Vesconite bearings is easier than metal backed bearings.

Press fitting Vesconite bearings can befitted using mechanical orhydraulic presses. Careneeds to be taken that thebearing is fitted square to thehousing and is well supported,preferably with a mandrel.

Lead in chamfers on theVesconite bearing and themetal housing ensure that thebearing will not be scoredduring installation.

mandrel

diameter30

chamfer

Vesconite bearingpacked in a containerwith dry ice.

Vesconite bearingpacked in a container supported bywooden blocks100-150 mm(4-6) high.

Insulationmaterial

Lid

Liquidnitrogen upto 50mmdeep

Lead inchamfer

Interference Bearingoutsidediameter

Housingdiameter

Runningclearance

Wallthickness

Shaftdiameter

Bearinginsidediameter

16

Mechanical securingAs an alternative to using aninterference fit, variousmechanical securingmethods may be used.

Operation of Vesconitebearings above 70C (160F)may result in loosening of thepress fit. In this case thebearing should be split andsecured mechanically to stoprotation and axial migration.

BondingUse an epoxy, Loctite orother suitable bonding agentsfor metal on plastics whichwill sustain the expectedoperating temperature. Theroughening of both surfaceswill improve the bond.

The disadvantage of thismethod is that the bond willneed to be broken when thebearing is removed.

Keeper platesKeeper plates arerecommended to avoid axial

movement of the bearing.Take care that no excessivepressure is placed on thebearing.

Grub or locating screws Grub screws are aconvenient and effective wayto stop rotation and axialmigration. The Vesconitebearing should be drilled toaccept the grub screw. Thisis to avoid excessive spotpressure being placed on thebearing which could lead tocracking or distortion.

Ensure that grub screws aresuitably bonded or securedinto their threads so that theydo not vibrate or work looseand cause damage to thepump.

Flanged bearing securedwith bolts An advantage of a flangedbearing is that the flangeallows for easy installationand removal of the bearing.

Housings and shafts

Shaft materials Metal mating surfaces mustsuit the media and wearconditions encountered.When operating in sandy orabrasive conditions, hardshaft surfaces ensure longershaft as well as bearing life.

Hardchrome plated surfacesare ideal.

As a general rule, the harderthe shaft surface, the betterthe results that will beachieved with Vesconitebearings.

Shaft hardnesses of Rc > 50are ideal, however the

hardness of a 316 stainlesssteel is usually acceptable.

Corrosion resistant stainlesssteels and admiralty andgunmetal bronze liners aregenerally satisfactory asmating surfaces forVesconite.

Carbon steel and hardenedsteel shafts may be used asmating surfaces providedthey do not corrode underthe conditions of use.

Housings and casingsmaterials

Housing metals are not critical as long as they do not corrodeseverely under the operating conditions.

keeper plate

edge wellchamfered

grub screw

split flangedbush

17

Machining tolerances Standard ISO machining tolerances of H7 for metal housingsand h7 for metal shafts are recommended for use with Vesconitebearings.Housing / shaft diameter in mm ISO tolerances

Housing / shaft diameter in inchesISO tolerances converted to inch measurements

Since synthetic materials such as Vesconite and VesconiteHilube have a wider tolerance specification, metal matingsurfaces machined to closer tolerances than this standard areseldom required.

10 - 18 18 - 30 30 - 50 50 - 80 80 - 120 120 - 180 180 - 250 250 - 315

Housing H7 Upper (mm) +0.018 +0.021 +0.025 +0.030 +0.035 +0.040 +0.046 +0.052

Lower (mm) 0 0 0 0 0 0 0 0

Shaft H7 Upper (mm) 0 0 0 0 0 0 0 0

Lower (mm) -0.018 -0.021 -0.025 -0.030 -0.035 -0.040 -0.046 -0.052

0.4 - 0.7 0.7 - 1.2 1.2 - 2.0 2.0 - 3.15 3.15 - 4.72 4.72 - 7.1 7.1 - 10.0 10.0 - 12.4

Housing H7 Upper () +0.000 71 +0.000 83 +0.001 0 +0.001 2 +0.001 4 +0.001 6 +0.001 8 +0.002 1

Lower () 0 0 0 0 0 0 0 0

Shaft H7 Upper () 0 0 0 0 0 0 0 0

Lower () -0.000 71 -0.000 83 -0.001 0 -0.001 2 -0.001 4 -0.001 6 -0.001 8 -0.002 1

Surface finishes of shafts The surface finish of the shaftis important to ensure longbearing life. Rough surfacefinishes and corroded andscored shafts will causeaccelerated wear of Vesconitebearings and should beavoided.

A recommended ground finishof 0.5 m Ra (0.002 microinchRa) is ideal. Shaft roughnessshould not exceed 2.5 m Ra(0.010 microinch Ra).

For solid drawn shafts whichhave axial tool marks,roughness should be lessthan 0.5 m Ra (0.002microinch Ra).

Shafts should be round andnot oval.

Where shafts with a tendencyto corrosion cannot beavoided, Hitemp 150 may beconsidered as a possiblesolution.

Surface finishes ofhousings and casings

The surface finish on thehousing is not critical asthere is no movement afterinstallation. To facilitateinstalling the bearing thehousing surface should besmooth. Lead in chamfersare advised to avoid scoringor shaving of the bearingduring installation.

Ovality of the housing needsto be avoided. If housingovality presents a problemthen it is best to install thebearing and then machinethe inside diameter to sizeafter installation.

Surface finishes ofVesconite bearings

The Vesconite bearingsurface finish is not criticalon account of its lowerhardness compared to the

metal mating surface. Astandard machined surface issufficient.

18

Metric Imperial

Maximum design load (static, oscillating or occasional movements) 30 MPa 4,250 psi

Linear expansion at 65% relative humidity 0.04% 0.04%

Linear expansion - saturated 0.07% 0.07%

Immersed 80C 175F

Dry or grease / oil lubricated 100C 212F

Thermal coefficient of expansion 6 x 10-5 mm/mm/C 3.3 x 10-5 in/in/F

Density / specific gravity 1.38 g/ml 1.38

Modulus of elasticity 2.2 GPa 493 000 psi

Chemical Name %

Butyl acetate Butyl amine Butyl chloride Butyric acid Calcium chloride Calcium hypochlorite Calypsol greases Carbon disulphide Carbon tetrachloride Caster oil Cellosolve Chloride of lime Chlorine (gas-dry) Chlorine dioxide Chlorine in water Chloroacetic acid

Chemical Name %

Anti freeze Aqua regia ASTM Oils Barium chloride Barium salts Benzaldehyde Benzene Benzyl alcohol Benzyl chloride Bleaching lye Bleaching solution Boric acid Brake fluid Bromine Butane Butanol

Chemical Name %

Acetaldehyde Acetic acid 10 Acetic acid 100 Acetic anhydride Acetone Acetonitrile Acetophenone Acetyl chloride Aluminium chloride 10 Aluminium sulphate 50 Ammonia Conc Ammonium hydroxide 10 Ammonium sulfate 50 AmyI acetate AmyI alcohol Aniline

Typical properties of Vesconite and Vesconite Hilube

Chemical resistance chart

Typically Vesconite andVesconite Hilube are limitedto 80C (175F) in immersedconditions and 100C (212F)in dry conditions.

For higher operatingtemperatures, please contactVescoPlastics with details ofyour application.

Temperature rating of Vesconite

This chemical resistance chartis given as a guide only. Theresistance data are anestimate at the concentrationsnoted at ambient temperatureof 25C (77F).

The aggressiveness ofchemical solutions generallyincreases with higher

concentrations andtemperatures. While generalguidelines may be provided,every application needs to beconsidered individually.

It is recommended to checkthe resistance in practicalfield tests in the solutions inquestion.

Resistance at 25C (77F) forVesconite and VesconiteHilube.

Resistant Partly resistant Not resistant

Hitemp 150 is designed forimmersed temperatures of upto 125C (250F) and 150C(300F) in dry conditions.

Guide maximumoperating temperature

19

Chemical Name %

Chlorobenzene Chloroform Chlorosulfonic acid Chromic acid 40 Citric acid 10 Copper sulphate Cottonseed oil Cresol Cyclohexane Cyclohexanol Cyclohexanone Decalin Detergents 25 Dibutyl phthalate Diesel Diethyl ether Diethylene amine Diethylene glycol Dimethyl formamide Dioctyl phthalate Dioxane Ethanol Ether Ethyl acetate Ethyl alcohol Ethyl chloride Ethylene dichloride Ethylene glycol Ferric chloride Fixer solution Fluorine (gas) Formaldehyde Formic acid 10 Formic acid 90 Freon Furfural Gasoline Glycerine Glycerol Glycol Grease Heptane Hexane High octane petrol Hydrobromic acid 50 Hydrochloric acid 36 Hydrochloric acid 100 Hydrofluoric acid 5 Hydrofluoric acid 40 Hydrofluoric acid 50

Chemical Name %

Hydrogen peroxide 35 Hydrogen sulfide (gas) Ink lodoacetic acid Isopropanol Kerosene Linseed oil Lubricating oil Magnesium chloride Methanol Methyl alcohol Methyl ethyl ketone Methyl glycol Methylene chloride Methylene chloride Mineral oils n-Hexane Nickel chloride Nitric acid 10 Nitric acid 40 Nitrobenzene Octane Oil of cloves Oleic acid 100 Olive oil Oxalic acid Ozone (gas) Paraffin Perchloroethylene Petrol Phenol Potassium bichromate 10 Potassium bromide Potassium carbonate Potassium chloride 10 Potassium dichromate 10 Potassium hydroxide 1 Potassium hydroxide 10 Potassium hydroxide 60 Potassium permanganate 25 Potassium sulphate Propane Propanol PropyI alcohol Pyridine Rapeseed oil Silicone fluids Silver nitrate Soap solutions 1 Sodium bicarbonate 10

Chemical Name %

Sodium borate Sodium carbonate 20 Sodium chloride 25 Sodium hydroxide 1 Sodium hydroxide 10 Sodium hydroxide 60 Sodium hypochlorite 20 Sodium nitrate 10 Stannic chloride Stearic acid Sucrose Sulfur dioxide (gas) Sulfuric acid 10 Sulfuric acid 70 Sulfuric acid 96 Tea Teterahydrofurane Tetralin Toluene Transformer oil Trichloroacetic acid Trichloroethane Trichloroethylene TricresyI phosphate Triethanol amine Triethylene glycol Turbo oil Turpentine Urea Vaseline Vegetable oils Vinyl chloride Water Water (sea) Wine Xylene Zinc chloride Zinc sulfate

20

The easiest way to dimension Vesconite bearings is to use the internet online Design-a-Bearing calculatorson www.vesconite.com.

Within seconds Design-a-Bearing gives thecorrect interference fits,running clearances, groovesizing and tolerances acrossa wide range of operatingtemperatures.

The standard designcalculations for the use of

Vesconite and VesconiteHilube in pump applicationsare given below from firstprinciples. These calculationsare for free standing bushesbefore installation.

The same equations apply toboth Vesconite and VesconiteHilube.

Vesconite and Vesconite Hilube Size Calculations

Worked example - Design a bearing for the following housing and shaft sizes:Metric

Housing size: 75 mmShaft size: 50 mm

Press fit = 0.05 + 0.002 x 75 mm= 0.20 mm

75Bore closure = 0.20 x mm50= 0.30 mm

Assembly clearance = 0.05 + [0.02 x 0.5 x (75 50)] mm

= 0.30 mm

Outside diameter = 75 + 0.20 mm= 75.20 mm

Inside diameter = 50 + 0.30 + 0.30 mm= 50.60 mm

Inches

Housing size: 3Shaft size: 2

Press fit = 0.002 + 0.002 x 3= 0.008

3Bore closure = 0.008 x 2= 0.012

Assembly clearance = 0.002 + [0.02 x 0.5 x (3 2)]

= 0.012

Outside diameter = 3 + 0.008= 3.008

Inside diameter = 2 + 0.012 + 0.012= 2.024

Interference fits/Press fits

The most common method for securing a Vesconite bearing.Calculated as:

Press fit = 0.05 + (0.002 x housing ) mm

Press fit = 0.002 + (0.002 x housing ) inches

Bore closure The closure of the inside diameter when a bearing is pressedinto a housing is called the bore closure.

housing diameter Bore closure = press fit x

shaft diameter

Assembly clearance This is the difference in diameter between the bearing insidediameter and the shaft.

Assembly clearance = 0.05 + (0.02 x wall thickness) mm

Assembly clearance = 0.002 + (0.02 x wall thickness) inches

Calculation of thebearing dimensions

Outside diameter = housing diameter + total press fit

Inside diameter = shaft diameter + bore closure + assemblyclearance

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For moderate temperatures from 50 to 70C (120 to 160F), an extra clearance is required toallow the bearing to expand without the danger of shaft seizure.

Extra clearance = [(Housing diameter)2 - (Shaft diameter)2] x (Tmax - 50) x 6 x 10-5 mm

Shaft diameter

Extra clearance = [(Housing diameter)2 - (Shaft diameter)2] x (Tmax - 120) x 3.3 x10-5 inches

Shaft diameter

Inside diameter = shaft diameter + bore closure + assembly clearance + additional clearance

If Tmax = 60C

Extra clearance = (752 - 502) x (60 - 50) x 6 x 10-5 mm

50= 0.04 mm

If Tmax = 140F

Extra clearance = (32 - 22) x (140 - 120) x 3.3 x 10-5

2= 0.0017

For temperatures higher than 70C (160F), a minimum expansion gap is required

Expansion Gap > 0.5 + [Housing diameter x 3.14 x (Tmax-20) x 6 x 10-5] mm

Expansion Gap > 0.020 + [Housing diameter x 3.14 x (Tmax-70) x 3.3x10-5]

Outside diameter = housing diameterInside diameter = shaft diameter + assembly clearance

If Tmax = 80CExpansion Gap > 0.5 + 75 x 3.14 x (80 - 20) x 6x10-5 mm

= 1.3 mmOutside diameter = Housing diameter

Tmax = 175FExpansion Gap > 0.02 + 3 x 3.14 x (175 - 70) x 3.3x10-5

= 0.053Outside diameter = Housing diameter

For temperatures below 0C (32F), an additional press fit is required to ensure that the bearingstays in place.Additional press fit = (0 -Tmin) x 5.4 x 10-5 x Housing diameter mmAdditional press fit = (32 - Tmin) x 3.0 x 10-5 x Housing diameter inches

Total press fit = standard press fit + additional press fitOutside diameter = housing diameter + total press fitInside diameter = shaft diameter + bore closure + assembly clearance

If Tmin = -20CExtra press fit = [0-(-20)] x 5.4 x 10-5 x 75 mm

= 0.08 mmTotal press fit = 0.2 + 0.08 mm

= 0.28 mm

If Tmin = -4FExtra press fit = [32 - (-4)] x 3.0 x 10-5 x 3

= 0.003Total press fit = 0.008 + 0.003

= 0.011

22

Temperature compensation

The bearing dimensionscalculated above assumemeasurement of the bearing at20C (70F). If there is a largevariance between the actualmachining and operationtemperatures, the resultingdifference in sizing could resultin incorrect bearing operationor premature failure.

Sizes need to be adjusted tothe machining temperature toensure that they are thecorrect size at operationaltemperatures.

Machining after installationIf it is necessary to machine the bearing to size after installation, the following equations apply:

Outside diameter = housing diameter + total press fitInside diameter = shaft diameter + assembly clearance + extra clearance

Outside diameter = 70 + 0.19 mm= 70.19 mm

Inside diameter = 50 + 0.25 + 0.27 mm= 50.52 mm

Outside diameter = 3 + 0.008= 3.008

Inside diameter = 2 + 0.012 = 2.012

Bearings that are long (lengthgreater than diameter) orhave thin walls requireadditional care.

The tolerances advised onVesconite are wider than fortypical metal tolerancesdue to the higher thermalexpansion rate ofVesconite. If bearings aredesigned with smallertolerances, then it isadvisable to consider the

machining and checkingtemperatures.

Where fine tolerances arerequired as can be the casewith wear rings, first fit theVesconite into the casingand then machine to size.

It is usually best to specify anoutside diameter toleranceand a wall thicknesstolerance. This reduces therisk of the stacking oftolerances that could lead toshaft seizure or a loose fit.This is most applicable onthin bearings and wear rings.

Machining Tolerances

Suggested Vesconite machining tolerances are:

Vesconite can be machinedon standard machiningequipment.

Standard Minimummm inches

Outside diameter tolerance 0.1% 0.025 0.001

Inside diameter tolerance 0.1% 0.025 0.001

Wall thickness tolerance + 0.0 / -0.5% + 0.0 / -0.025 0.0 / -0.001

Length tolerance + 0.0 / -0.5% + 0.0 / -0.3 + 0.0 / -0.01

23

Vesconite and Vesconite Hilube are easily machinedto fine tolerances on standard metal workingequipment.

Vesconite should not be clamped like a metal, butshould be clamped carefully to avoid distortion.

Cooling water should be used where possible tocool the cutting surface.

Take cuts no more than 2 mm (0.1") deep at a time.

Allow the bush to cool before taking the final cut.

Cutting Angles

Machine outside diameterMachine bush outside diameter using an

external turning tool.

Machine flange outside diameter if needed.

Face the end of the bush.

Part to lengthPart bush to length using a parting tool.

Ensure that bush does not fall when parted.

Cut to lengthAllow extra length for chucking, parting and

facing, usually 25 mm (1").

Cut bushing to length with a cut-off saw.

Chuck with internal support discSet the bush squarely in the chuck.

Use an internal support disc machined to size,made of any available material, approximately 10to 25 mm thick (1/2" to 1").

Tighten the chuck lightly - only enough to supportthe bush. Vesconite should not be clamped like ametal.

Machine inside diameterMachine bush inside diameter using a

boring bar. Ensure that there is not an excessivebuild-up of shavings inside the bush.

Grooves may be added at this stage if required.

Machining guidelines for Vesconite

1STEP

2STEP

3STEP

4STEP

Machining straight and flanged bushes in small quantities

internalsupport disc

boring barmachininginside diameter

chuckjaws

chuck

Vesconitebush

5STEP

machiningoutside diameter

facingend of bush

parting bush to length

Diameter mm 0-50 50-100 100-150 150-200 200-250 250-300 300-400 400-500

Diameter inches 0-2" 2-4" 4-6" 6-8" 8-10" 10-12" 12-16" 16-20"

RPM 600-2000 500-600 450 350 240 240 160 120

Cutting speeds - Maximum of 300 m/min (1000 fpm)

Cutting Feeds Rough turning:0,5 - 0,7 mm per revolution 0.25" - 0.35" per revolutionFinish turning: 0,4 - 0,4 mm per revolution 0.15" - 0.25" per revolution

0.4mm 0.8mm radius0.15" 0.40" radius

60

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Stock availabilityA large range of Vesconiteand Vesconite Hilube stockshapes are available fromcenters worldwide tomanufacture pumpbearings. Vesconite andVesconite Hilube can besupplied as standard stockshapes at short notice or asfinal machined customcomponents. Use thewww.vesconite.comstockfinder link to findsuitable material.

Tubes / bushingsStocked in 1 meter (39) lengthsfor shafts from 6 to 650 mmdiameter (1/2 to 26) in a largerange of standard sizes.

Vesconite More than 150bushing sizes

Vesconite Hilube More than50 bushing sizes

RodsStocked in 1 meter (39)lengths in diameters from 8to 160 mm (5/16 to 6)

PlatesStocked in widths up to600 mm (23) wide and 50mm (2) thick. Ideal formachining large diameterwear rings.

Moulded partsPump bearings can bemoulded by VescoPlasticsinto finished or a semi-finished form for costeffective solutions on largerquantity requirements.

DisclaimerThis design manual is basedupon many years ofexperience of VescoPlasticsand VescoPlastics Sales (theCompanies) in manufacturingand designing polymericbearing materials. Experienceshows that no twoapplications are the same inevery detail so theCompanies encourage thatevery application be treatedas individual and unique.

This information is offered ingood faith as part of ourclient service, but favourableresults cannot beguaranteed. This informationis intended for use bypersons with technical skill,at their discretion and risk.The purchaser mustdetermine the suitability ofthe goods for their intendedpurpose.

The Companies reserve theright to change or amend anyrecommendation orspecification without notice.

Goods are supplied on theexpress condition that theCompanies liability is limitedto the replacement ofdefective goods or materials.

The Companies do not holdthemselves responsible forany damage, incidental orconsequential loss sufferedas a result of the use ofgoods supplied.

Acceptance of goods will beheld to imply agreement tothe above conditions.

25

What www.vesconite.com can do for you

Material SafetyData SheetsSafety information anddrinking water certificates.

Other useful informationHome page available in various languages including, Finnish, Portuguese,Russian, Afrikaans, German, French, Italian, Chinese, Spanish....

BulletinboardOther industriesincluding railways,marine, transport,mining.... Frequently

asked questions

Stock finderFind the closest Vesconite and VesconiteHilube stocks near you to meet therequirements of your application.

Prototypes,inquiries andquotesTesting Vesconite in yourapplication may be the onlyway to demonstrate thelong life of Vesconite. If youwould like VescoPlastics toassess your application, fillin the details and submit fora prompt assessment or aquotation for yourcomponents.

Application success storiesVesconite has been successful many timesbefore. Details of many successfulapplications of Vesconite and VesconiteHilube fitted to pumps and other industries.

Design-a-bearingcalculatorsDesign your pump bearingquickly and correctly withon-line calculators in metricunits or inches.Design-a-Bearing willspecify the correct fits,clearances and machiningtolerances for bearingparameters interted.

26

Axial flow / mixed flow

LineshaftPump bowlStuffing boxSuction cover

Application assessment or quotationPlease comlete the form and fax to +27 11 616 22 22 or +27 11 615 38 10.If possible include a cross section or assembly diagramshowing pump design and bearing location.

Centrifugal

Wear ringSupport bearing

Sump

Impeller supportShaft supportWear ring

Split case

Wear ringSupport bearingLantern ring

In line

Wear ringSupport bearing

Submersible

Lineshaft

Other (specify)

Pumped product Water CleanOther (specify) Dirty (specify)

Bearing size mm inches Split bearing required Yes No

Housing/casing diameter Flange diameter (if required)

Shaft/impeller diameter Flange thickness

Bearing length Number of bearings

Operational conditions

Rotational speed (RPM) Maximum temperature C F

Load kg lbs Minimum temperature C F

Current material used

Bronze Elastomer Rubber Cutlass Other (specify)

Lubrication Product Water Grease Oil None

Contact details

Company Contact Name

E-mail Website www

Address

Country Postal / Zip code

Telephone + ( ) Fax + ( )

Please quote quantity per order Quantity per year

Toll free: USA 1 866 635 7596UK 0800 731 9745

Brazil 0 800 891 8710Chile 800 104 646

Portugal 800 827 007UAE 1 800 027 01 03

Canada 1 866 682 3484

PO Box 40647, Cleveland, South Africa, 2022.Telephone: + 27 11 616 11 11Fax: + 27 11 616 22 22

www.vesconite.comvesconite@vesconite.com