i CONTENTS - Cole-Parmer · 2016. 11. 15. · components of the viscometer, immediately turn off the unit, discon-nect the viscometer from the power supply and contact Cole-Parmer®.

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Cole-Parmer® 98936 Series ROTATIONAL VISCOMETERSVersion 5.1—June, 1999; Cole-Parmer® Instrument Company625 E. Bunker Court • Vernon Hills, IL 60061-1844 • USA

CONTENTS

1 INTRODUCTION 1Overview ............................................................................................................................ 1Specifications...................................................................................................................... 2Safety warnings .................................................................................................................. 3

2 UNPACKING AND INSTALLATION 5Unpacking ........................................................................................................................... 5Installation .......................................................................................................................... 5Operator safety.................................................................................................................... 6Operation ............................................................................................................................ 7Operation notes ................................................................................................................... 9

3 MODELS 98936-00/05 11Overview .......................................................................................................................... 11Calibrating the 98936-00/05 viscometer .......................................................................... 13Spindles used with the Temperature Controlled Unit ....................................................... 15Extending the 98936-00/05 range ..................................................................................... 16Increasing the 98936-00/05 sensitivity ............................................................................. 16

4 MODELS 98936-10/15 19Overview .......................................................................................................................... 19Calibrating the 98936-10/15 ............................................................................................. 20Spindles used with the TCU ............................................................................................. 22Extending the 98936-10/15 range ..................................................................................... 23

5 MODELS 98936-20/25 25Overview .......................................................................................................................... 25Calibrating the 98936-20/25 ............................................................................................. 26Spindles used with the TCU ............................................................................................. 27

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CHAPTER

1 INTRODUCTION

Overview

The Cole-Parmer® 98936 Series Rotary Viscometers measure viscosityby rotating a disk or cylinder while the disk is immersed in the materialbeing tested. The rotating cylinder or disk (spindle) is turned at a knownrate. The instrument measures the torque required to turn the spindle.From the spindle speed, torque measurements, and spindle characteris-tics, the 98936 Series viscometers calculate and display the viscosity.

Viscosity Ranges The various spindle sizes and range of spindle speeds available allow the98936 Series viscometers to measure a wide range of viscosities. For afluid of a given viscosity, the drag is greater as the rotation speed of thespindle (or the size of the spindle) is increased. By combining differentspindles and speeds of rotation, the operator can select an optimum rangeof measurement within the range of the viscometer.

Precision The 98936 Seriesviscometers achieve aprecision of ± 1 percentof full scale, or ± 1digit, whichever isgreater. Optimumperformance andrepeatability areachieved if the viscom-eter is used between 80percent and 90 percentof the full operationscale for the speed/spindle combination inuse.

Spindle/Speed Selection Spindles and speedsshould be selected tomaximize the accuracyof the readings. Theabsolute accuracy of the98936 Series viscom-eters is approximatelyone percent of the fullrange. Therefore,viscosity measurementsshould be taken using thesmallest range possible. Figure 1: The V-2000

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Applications The 98936 Series viscometers are designed to be used for precise viscositymeasurements of fluids having a wide range of viscosities. Measurementscan also be made using the same spindle at different speeds of rotation tofind the rheological properties of a material at different shear rates.

Thermometry To insure accurate temperature readings, follow established thermometrypractice. Allow ten minutes after inserting the thermometer before takingtemperature readings. When checking sample temperature, keep themercury bulb away from the bottom and sides of the sample container.Cole-Parmer® recommends placing the bulb near the spindle.

Remove the thermometer before taking viscosity readings. The thermom-eter may interfere with spindle rotation, resulting in incorrect readings.

Manual This manual is designed to inform the operator about:

! Functions and operations of the 98936 Series viscometers! Different configurations and capabilities of 98936 Series viscometers! Maintenance and repair of the 98936 Series viscometers

Specifications

Common Specifications The following table shows specifications which apply to all of the 98936Series viscometers:

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Individual Specifications The table below shows specifications which differ between the viscom-eters:

Safety warningsPlease observe the following safety procedures and notices for properoperation of your 98936 Series instrument:

• Make sure that your unit is operated only by qualified personnel• Make sure that you read and understand all operating instructions

and safety precautions listed in this manual before installing oroperating your unit. If you have questions regarding instrumentoperation or documentation, contact Cole Parmer®.

• Deviation from the installation, operation or maintenance proceduresdescribed in this manual may result in a hazardous situation and mayvoid the manufacturer's warranty.

• Transport the unit with care. Sudden jolts or drops may causedamage to components.

• Observe all warning labels.• Never remove warning labels.• Never operate damaged or leaking equipment.• Always turn off the unit and disconnect the mains cable from the

power source before performing service or maintenance procedures,or before moving the unit.

• Never operate the equipment with damaged mains power cables.• Refer all service and repairs to qualified personnel.

In addition to the warnings listed above, additional cautions are postedthroughout the manual. These warnings may be designated by an appro-priate symbol inside an equilateral triangle. General cautions are indi-cated with an exclamation point (see diagram, left). Read and followGeneral Caution

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these important instructions. Failure to observe these instructions canresult in permanent damage to the unit, significant property damage,personal injury or death.

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CHAPTER

2 UNPACKING AND INSTALLATION

The 98936 Series viscometer is shipped in a single box.

Unpacking

Remove all components from the shipping carton.

Remove all foam and other packing materials from the components.

CAUTION To protect the spindle attachment, the viscometer is shipped with a plasticcap over the delicate mechanism, located on the underside of the viscom-eter head. The cap is secured with a #10 screw which must be removedbefore removing the cap. Remove the screw and gently slide the cap offthe metal housing. Retain the #10 screw and the cup in the event that theunit must be transported.

Inspect all components for damage. Report any damage to the shipperand to Cole-Parmer® immediately.

NOTE Retain all packing materials until the viscometer is connected and func-tioning properly. If any component must be returned to Cole-Parmer®, itshould be packed in its original shipping container.

Before beginning assembly of the viscometer, consult your packing listand verify that all components listed are present.

Returning equipment Refer to the final chapter of this manual for instructions on returning anydefective equipment.

Installation

Remove the components from their packing box and place them on astable laboratory bench or table.

Mount the viscometer head on its laboratory stand by sliding the rod atthe back of the viscometer head through the hole in the gear clampassembly on the rack post. Then tighten the alignment clamp on theunderside of the gear clamp assembly to secure the viscometer head tothe assembly.

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Levelling the viscometer Level the viscometer by adjusting the three mounting legs located on theunderside of the viscometer stand. Check the bubble level on the mount-ing platform and adjust the mounting legs until the bubble is centered.

Supplying power Make sure that thepower switch is off.Then connect the DIN-5cable from the poweradaptor to the rear ofthe viscometer. Plug thepower cord into thethree-prong connectoron the power adaptor(see Figure 2) and plugthe other end of thepower cord into theelectrical power source.

CAUTION Do NOT exceed voltagespecifications of thepower adaptor ordamage may occur.

IMPORTANT Secure the spindleguard bracket in itsplace on the undersideof the viscometer usingthe thumbscrew pro-vided (see Figure 3).

Operator safety

All technicians who use a 98936 Series viscometer should follow thesebasic safety procedures:

1. Do not place the viscometer on an unstable cart or stand. The vis-cometer should be placed on a stable laboratory table or bench.

2. Keep the viscometer and power adaptor away from tubs, sinks, orother water vessels. If any liquids are spilled into the electroniccomponents of the viscometer, immediately turn off the unit, discon-nect the viscometer from the power supply and contact Cole-Parmer®.

3. Do not position power cords so that they are likely to be walked onor pinched by items placed on or against them. Keep all connectionsas neat as possible.

Figure 3: Attaching spindle guard bracket

Figure 2: Attaching the power adaptor

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4. Do not attempt to service the viscometer by removing panels andtrying to make repairs. Contact Cole-Parmer® for all service andrepair needs.

Operation

CAUTION Always select spindle and speed combinations to match the anticipatedviscosity range of the sample to be measured. Inappropriate settings maycause damage to the rotor/spindle apparatus. Refer to the chapters onthe individual instruments for tabular data on spindle selection.

General operation procedure 1. Make sure the faces on the shaft and the spindle nut are smooth andclean to ensure good contact and prevent eccentric spindle rotation.

2. Make sure that the spindle guard bracket is clean of residual samplefrom previous tests or calibrations. If necessary, remove and cleanthe bracket. Residual sample on the bracket or the spindle mayadversely affect the reliability of viscometer measurements.

3. Attach the spindle to the shaft of the viscometer by holding the shaftfirmly with one hand and lifting it slightly. Then align the spindlewith the bottom of the rotor shaft (see Figure 4) and screw thespindle in place with the other hand by rotating it counterclockwise(left-hand thread). Do not apply horizontal pressure to the shaft oryou may bend the shaft or damage the delicate bearing mechanism.

Figure 4: Attaching spindle shaft to the viscometer

4. Raise the viscometer unit using the wheel on the rear of the viscom-eter stand. Turn the wheel clockwise to raise the unit until the rotor androtor guard bracket can clear the lip of the sample fluid container.

NOTE With a disk-type spindle, it is necessary to tilt the spindle slightly whileimmersing the spindle to avoid trapping air bubbles on the spindle’ssurface. It is easier to immerse spindles of this type in the sample con-tainer BEFORE attaching the spindle to the viscometer shaft.

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5. Carefully slide the sample container into place beneath the rotorapparatus and gently lower the rotor/guard bracket into the samplecontainer, using the wheel at the back of the viscometer holder.

NOTE To regulate the motion of thewheel, use a Phillips screwdriverto turn the upper screw locatedunder the roller at the back of thegear clamp assembly. For astiffer action and greater stability,tighten the screw (see Figure 5).

6. Continue lowering the rotoruntil it is immersed insample up to the groovemarked on the rotor shaft.

CAUTION Do not permit the spindle/rotor shaft assembly to make contact with thesides of the sample container. This could damage the viscometer shaftalignment and distort future viscometer readings.

7. Set the rotation speed with the dial on the right side panel of theviscometer.

8. Turn the viscometer on by using the POWER switch. If the OFFRANGE (—) indicator comes on immediately, it will usually turnoff after 1 or 2 revolutions of the spindle.

9. Wait 20-30 seconds for the viscometer to stabilize (the time requiredfor stabilization depends on the spindle speed; speeds below 1 rpmmay require at least 1 complete revolution of the spindle).

10. Record the viscosity measurement indicated on the front paneldisplay.

The 98936-00/05 and 98936-10/15 models display readings in centipoise(the 98936-20/25 displays readings in poise). The last 2 digits aremultipliers of x10 and x100. They are switched on automatically forsettings of the spindle control requiring higher readings. The display willshow data in four significant digits:

0 to 9,999 cP: in 1 cP increments0 to 99,990 cP: in 10 cP increments0 to 999,900 cP: in 100 cP increments

Concluding the test 11. At the conclusion of testing, switch off the power to the viscometer.

12. Rotate the wheel at the rear of the viscometer stand clockwise toraise the spindle free of the liquid sample container.

13. Remove the sample container, taking care to insure that the spindledoes not touch the sides of the container.

Figure 5: Regulating the viscometermotion on the shaft

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Operation notes

OFF RANGE warning The OFF RANGE (—) warning is displayed when the viscometerattempts to make measurements which are:

1) beyond the maximum range of a spindle and speed combination,or

2) beyond the display capability of the viscometer for any particularrange.

Reducing the spindle size or rotation speed will bring the viscometerinto range (providing measurements are being made within the rangeof the viscometer).

Viscometer accuracy The accuracy of the viscometer is specified as a percent of the viscos-ity range for the spindle/speed combination selected. Most accurateresults are obtained by the careful choice of spindle for the materialbeing tested. Ideally, the target viscosity should be between 80 percentand 90 percent of the maximum range for the spindle/speed combinationselected.

Repeat readings The viscometer has an accuracy of ± 1 percent of full scale in itsoptimum range. Repeat readings will normally be within ± 0.2 percentof full scale. Optimum performance and repeatability are achieved ifthe viscometer is used between 80 percent and 90 percent of its fulloperation scale.

Stability of readings Viscosity readings should stabilize within 30 seconds of setting therotor speed (slightly longer if the lowest rpm speeds are chosen). Ifviscosity readings do not stabilize after 30 seconds of spindle rotation,the test material may be thixotropic, or the sample temperature maynot be constant.

Temperature has a significant effect on the viscosity of most materials.The viscosity of non-Newtonian and thixotropic materials varies withrespect to shear rate. Comparative measurements of viscosity, there-fore, should be made using the same spindle and speed.

Spindle run-out With a new, straight spindle, some run-out (wobble) is normal due tothe gimbal-mounted design. Run-out may be accentuated by a bentspindle shaft. Normal run-out should not exceed 0.125".

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CHAPTER

3 MODELS 98936-00/05

Overview

Spindle speeds Model 98936-00/05 instruments have 8 selectable spindle speeds:

0.3 revolutions per minute 6 revolutions per minute0.6 revolutions per minute 12 revolutions per minute1.5 revolutions per minute 30 revolutions per minute 3 revolutions per minute 60 revolutions per minute

The 98936-00/05 comes equipped with 4 standard spindles, designatedL1 through L4 (see Figure 6). Special spindles designated TL5, TL6, andTL7 can be used with the 98936-00/05 in conjunction with the Tempera-ture Controlled Unit and SmallSample Adapter.

Display The digital display of the 98936-00/05 reads from 1 to 9,999 followedby the appropriate zeros. Forexample, spindle L4 at 6 rpm willdisplay readings from 1 to 99,990cP in increments of 10 cP. However,the accurate range of the instrumentwith the L4 spindle at that speedsetting is 1,000 to 90,000 cP.

Spindle/Speed Selection Spindles and speeds should be selected to maximize the accuracy of the98936-00/05. The absolute accuracy of the 98936 Series viscometers isapproximately one percent of the total range. Therefore, viscositymeasurements should be taken using the smallest range possible. Forexample, if a sample has a viscosity of approximately 3500 cP, usespindle L3 at 30 rpm - this combination provides a range of 400 to3600 cP with an accuracy of ± 40 cP.

Viscosity Ranges The table on the following page shows the ranges obtainable withspindles L1 through L4, when rotated at each of the 8 speeds. Switchposition (speed) 4E allows readings to be taken up to 999,900 cP, using astandard L4 spindle:

Figure 6: L1-L4 spindles

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For a chart of 98936-00/05 series spindles and their respective ranges (in cP) see page 14.

Order information SPINDLE SIZE Cole-Parmer® CATALOGUE #L1 98936-55L2 98936-56L3 98936-57L4 98936-58TL5 98936-90TL6 98936-91TL7 98936-92

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Calibrating the 98936-00/05 viscometer

Calibration theory The 98936-00/05 is calibrated by measuring the viscosity of a knownstandard at a known temperature. The measured value for viscosity iscompared with the known value to produce a correction constant,expressed as the ratio of the actual to measured value. This constant maythen be used as a multiplier for measured values of other samples.

Standards Viscosity standards used for calibrating the 98936-00/05 are availablefrom Cole-Parmer®. Cole-Parmer® can supply standards to suit mostranges of the 98936 Series viscometers.

Container Size When calibrating the 98936-00/05, use a low form 600 ml Griffin beaker.

NOTE The L4 spindle has a reduced section in its shaft, rather than the groovefound on other spindles. The L4 spindle should be immersed in the fluidto the midpoint of this reduced section.

Correction Factors Readings taken in small containers and/or without the spindle guardbracket in place can only be considered as comparative measurementsunless correction factors are used with each spindle and container.

Follow the procedure below to obtain a correction factor for a specificspeed, spindle and container combination:

1. Measure the viscosity of a known standard material (at the specifiedtemperature) with the speed, spindle and container to be used.

2. Compare this measurement with the actual viscosity of the standardmaterial.

3. The ratio of the measured viscosity to the actual viscosity of thematerial can be used as a correction factor for the measurement oftest materials with this speed, spindle and container combination.

Air Resistance An additional correction for air resistance should be made at the highestspindle speed setting of 60 rpm. At 60 rpm, air resistance to the measur-ing device within the 98936-00/05 will have a small effect on the mea-surement. Measurements taken at this speed with any spindle should bereduced by 0.4 percent of full scale. To do this, multiply the measuredvalue by 0.996.

Viscous heating Measurements should be taken within two minutes of initiating rotorrotation, since viscous heating can affect viscosity readings, especiallywhen testing highly-viscous fluids.

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60 30 12 6 3 1.5 0.6 0.3

INCREMENTS OF 1 CENTIPOISE

50

100

1k

5k

10k(9 999 max)

100k(99 990 max)

1M(999 900 max)

CENTIPOISE(display)

INCREMENTS OF 100 CENTIPOISESPINDLENUMBER

4

7

3

6 & 2

1

5

SPINDLE SPEED (RPM)

4E

INCREMENTS OF 100 CENTIPOISE

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NOTE A condition of turbulent flow is created by the L1 spindle when rotating at60 rpm in materials with viscosities less than 15 cP. If measurements ofhigh accuracy are needed in this region, use the Low Centipoise Adapter(98936-70/72) accessory.

Spindles used with the Temperature Controlled Unit

Three spindles, TL5, TL6 and TL7, are required for use with the Tem-perature Controlled Unit (TCU).

Figure 7: Spindles used with the TCU

A standard 98936-00/05 viscometer is used, and multiplying factors areapplied to readings. Special spindles must be used. Consult the table onpage 12 for spindle selection information, noting the following:

NOTES

! All ranges measure from 0 to maximum cP (k = 1000).! The digital display reads from 1 to 9999, followed by appropriate zeros.! The minimum recommended reading is 10 percent of full scale.

Order information SPINDLE SIZE Cole-Parmer® CATALOGUE #

TL5 98936-90TL6 98936-91TL7 98936-92

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Extending the 98936-00/05 range

A feature which can be used to extend the range of the instrument up to900,000 cP is to operate the instrument with the Spindle Set Controlswitched to Spindle No. 1, regardless of the spindle in use. If the multi-pliers of (x10) and (x100) which appear at the right-hand side of thedigital display window at certain spindle speeds are ignored, readingsderived from one spindle may be taken by using the spindle setting foranother spindle and then dividing by the appropriate factor. This featureis limited to a maximum display reading of 9999.

If this feature is used, the viscometer readings must be divided by thefactors indicated in the following table in order to give the values in cP.

Increasing the 98936-00/05 sensitivity

For certain spindles, the sensitivity of the instrument can be increased byswitching the Spindle Set Control to a position not corresponding to thespindle in use.

All positions of the Spindle Set Control are related to each other byfactors of 1, 5, 20 or 100. If the multipliers of (x10) and (x100) whichappear at the right-hand side of the digital display window at certainspindle speeds are ignored, readings multiplied by 1, 5, 20 or 100 can beobtained with certain spindles. This feature is limited to a maximumdisplay reading of 9999.

The basic performance of the instrument is not altered if this technique isused, but it does improve the range of readings obtained where lesssensitive spindle/speed combinations are used. Readings displayed underthese circumstances must be divided by the appropriate factor to obtainthe corrected reading.

The following table indicates the divisor to use when the Spindle SetControl is set to a number which does not correspond to the spindle number:

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EXAMPLE When using an L1 spindle, the display readings can be increased 5 timesby switching the Spindle Set Control to 2, or by 20 times if the Spindle SetControl is switched to 3.

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CHAPTER

4 MODELS 98936-10/15

Overview

The Model 98936-10/15 has 8 selectable spindle speeds:

0.5 revolutions per minute 10 revolutions per minute1.0 revolutions per minute 20 revolutions per minute2.5 revolutions per minute 50 revolutions per minute5.0 revolutions per minute 100 revolutions per minute

The 98936-10/15 comes equipped with 6 standard spindles, designatedR2 through R7 (see Figure 8). Four additional spindles (TR8 throughTR11) can be used with the 98936-10/15 in conjunction with the Tem-perature Controlled Unit (TCU).

Figure 8: R2-R7 spindles

Display The digital display of the 98936-10/15 reads from 1 to 9,999 followed bythe appropriate zeros. For example, spindle R7 at 1 rpm will displayreadings from 1 to 999,900 cP in increments of 100 cP. However, theaccurate range of the instrument with the R7 spindle at that speed settingis 100,000 to 900,000 cP.

Spindle/Speed Selection Spindles and speeds should be selected to maximize the accuracy of the98936-10/15. Therefore, viscosity measurements should be taken usingthe smallest range possible. For example, if a sample has an anticipatedviscosity of approximately 4200 cP, use spindle R3 at 20 rpm — thiscombination provides a range of 500 to 4,500 cP with an accuracy of ±50 cP. If spindle R6 were to be used at 50 rpm, the range would be 2,000to 18,000 cP with an accuracy of ± 200 cP. The value derived using theR6 spindle would be less reliable.

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Viscosity Ranges The following table shows the ranges obtainable with spindles R2through R7, when rotated at each of the 8 speeds:


R2 98936-60R3 98936-61R4 98936-62R5 98936-63R6 98936-64R7 98936-65

Calibrating the 98936-10/15

Calibration theory The 98936-10/15 is calibrated by measuring the viscosity of a knownstandard at a known temperature. The measured value for viscosity iscompared with the known value to produce a correction constant,expressed as the ratio of the actual to measured value. This constant maythen be used as a multiplier for measured values of other samples.

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Standards Viscosity standards used for calibrating the 98936-10/15 are availablefrom Cole-Parmer®. Cole-Parmer® can supply standards to suit mostranges of the 98936 Series Viscometers.

Container size When calibrating the 98936-10/15, use a low form 600 ml Griffin beakerto contain the liquid standard.

NOTE The R7 spindle has a narrow neck in its shaft, rather than the groovefound on other spindles. The R7 spindle should be immersed in the fluidto the midpoint of this reduced section.

Correction Factors If containers other than the low form 600 ml Griffin beaker are to beused, it will be necessary to establish correction factors for absolutemeasurements.

To obtain a correction factor for a specific speed, spindle, and containercombination:


2. Compare this measurement with the actual viscosity of the standardmaterial, as indicated on the standard bottle.

3. The ratio of the measured viscosity to the actual viscosity of thematerial can be used as a correction factor for the measurement oftest materials with this speed, spindle and container combination.

Turbulent flow A condition of turbulent flow may be produced by certain spindles whenoperated at 100 rpm. A slight degree of non-linearity between indicatedand absolute viscosity may be noticed when reading lower viscosities.

NOTE If the 98936-10/15 should vibrate or fail to rotate the spindle whenstarted at 100 rpm, restart the 98936-10/15 at 50 rpm. Increase the speedto 100 rpm after smooth rotation has been established.

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Spindles used with the TCU

When the 98936-10/15 is operated in conjunction with a TemperatureControlled Unit (TCU), the spindles TR8, TR9, TR10, and TR11 must beused.

Figure 9: TR8-TR11 spindles

The following table shows the ranges obtained with these spindles whenrotated at each of the 8 speeds:

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Order information SPINDLE SIZE Cole-Parmer® CATALOGUE #TR8 98936-93TR9 98936-94TR10 98936-95TR11 98936-96

Extending the 98936-10/15 range

A feature which can be used to extend the range of the instrument up to7,200,000 cP is to operate the instrument with the Spindle Set Controlswitched to Spindle No. 8, regardless of the spindle in use. If this featureis used, the viscometer readings must be multiplied by the factors belowin order to give the values in cP.

**NOTE Ignore the multiplier zero which comes up when switched to Spindle No. 8.

Example To extend the range of the spindle R3, set the Spindle Set Control to 8,but use the R3 spindle. Readings must then be multiplied by 2 to givecorrect readings in cP.

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25


CHAPTER

5 MODELS 98936-20/25

Overview

The Model 98936-20/25 has 8 selectable spindle speeds:

0.5 revolutions per minute 10 revolutions per minute1.0 revolutions per minute 20 revolutions per minute2.5 revolutions per minute 50 revolutions per minute5.0 revolutions per minute 100 revolutions per minute

The 98936-20/25 comes equipped with 6 standard spindles, designatedR2 through R7 (see Figure 8). Four additional spindles (TR8 throughTR11—see Figure 9) can be used with the 98936-20/25 in conjunctionwith the Temperature Controlled Unit (98936-50/52).

Units of measure While the 98936-00/05 and 98936-10/15 measure and display values incentipoise, the 98936-20/25 measures and displays values in poise. Thelower ranges of the 98936-20/25 display from 0 to 999.9 poise, andhigher ranges display from 0 to 99,990 Poise.

Spindle/Speed Selection Spindles and speeds should be selected to maximize the accuracy of the98936-20/25. The absolute accuracy of the 98936 Series viscometers isapproximately one percent of the full scale reading. Therefore, viscositymeasurements should be taken using the smallest range possible. Forexample, if a sample has a viscosity of approximately 340 P, use spindle R3at 20 rpm - this combination provides a range of 40 to 360 P with an accu-racy of ± 4 P (one percent of full scale). Note that if spindle R2 were used at5 rpm, the display resolution would be enhanced (since the R2 spindlemeasures in increments of 0.1 poise) but the value would not be as reliable,since accuracy with that speed/spindle combination is only ± 6.4 P.


R2 98936-60R3 98936-61R4 98936-62R5 98936-63R6 98936-64R7 98936-65

Viscosity Ranges The following table shows the ranges obtainable with spindles R2through R7, when rotated at each of the 8 speeds:

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Calibrating the 98936-20/25

Standards Viscosity standards used for calibrating the 98936-20/25 are availablefrom Cole-Parmer®. Cole-Parmer® can supply standards to suit mostranges of the 98936 Series Viscometers.

Containers When calibrating the 98936-20/25, use a low form 600 ml Griffin beakerto contain the liquid standard. This type of beaker is obtainable from anygeneral laboratory supply company. Using a larger container will slightlyincrease the effective range of spindle R2 (there will be no effect on theranges of spindles R3 through R7).

NOTE The R7 spindle has a narrow neck in its shaft, rather than the groovefound on other spindles. The R7 spindle should be immersed in the fluidto the midpoint of this reduced section.

Correction Factors If containers other than the low form 600 ml Griffin beaker are to beused, it will be necessary to establish correction factors for absolutemeasurements.

To obtain a correction factor for a specific speed, spindle, and containercombination:

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2. Compare this measurement with the actual viscosity of the standardmaterial as found on the standard bottle.

3. The ratio of the measured viscosity to the actual viscosity of thematerial can be used as a correction factor for the measurement oftest materials with this specific speed, spindle and container combi-nation.

CAUTION If the 98936-20/25 should vibrate or fail to rotate the spindle when startedat 100 rpm, restart the 98936-20/25 at 50 rpm. Increase the speed to 100rpm after smooth rotation has been established.

Spindles used with the TCU

When the 98936-20/25 is operated in conjunction with a TemperatureControlled Unit (98936-50/52), the spindles TR8, TR9, TR10, and TR11must be used (see pages 22-23). The following table shows the rangesobtained with these spindles when rotated at each of the 8 speeds:

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29


CHAPTER

6 ACCESSORIES

This chapter describes equipment designed to work in conjunction withthe 98936 Series viscometers.

Low centipoise adapter (98936-70/72)

The Low Centipoise Adapter is used when very accurate measurementsof low viscosity fluids are required. It fits all 98936-00/05 and 98936-10/15 Series viscometer models and is easily installed or removed by meansof a single thumbscrew. The stainless steel assembly includes an adapter,spindle, chamber, end cap, and coupling nut.

Specifications The LCA specifications are listed in the table below:

Operating Instructions 1. Fit the viscometer measuringhead to the vertical supportand level the instrument.

2. Attach the mounting bracketto the viscometer using thethumbscrew.

3. Screw the coupling nut (com-plete with spindle and link) tothe shaft (see Figure 10).

Figure 10: Attaching the LCA

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4. Fit the end cap onto thesample tube, and fill thesample tube with 18 ml ofsample.

NOTE When using the end cap, asample volume of 18 ml isrequired.

5. Slide the sample tube upover the spindle (seeFigure 11).

NOTE When fitting the sample tube,be careful not to trap any air inthe test fluid. Tapping the sideof the tube will help removeany air bubbles.

6. Engage the pin on thebracket into the slot onthe sample tube collar andfix it in position using thethumbscrew (see Figure12).

7. If using a temperaturebath (or when measuringdirectly into a containerof fluid without the endcap), immerse the sampletube to the top edge of thecollar.

8. Read the viscosity and interpret results using the tables below.

OPERATION NOTES The LCA is most commonly used with the 98936-00/05 viscometer at 60rpm.

Correcting for windage To correct for windage:at 60 rpm, deduct 0.04 cP from readingat 30 rpm deduct 0.02 cP from reading

EXAMPLE Speed = 60 Spindle Setting = 4Test material displays a reading of 1040Viscosity = READING x FACTORViscosity = 1040 x 0.001Viscosity = 1.040 cP(Correction for windage - 98936-00/05 only): 1.040 -0.04 = 1.000 cP

Figure 11: Sliding the sample tubeover the spindle

Figure 12: Securing the sample tubecollar

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Small sample adapter (98936-80)

The Small Sample Adapter is a jacketed sample chamber enablingaccurate viscosity measurements to be taken using a very small samplevolume. It uses the same TL and TR spindles used by the TemperatureControlled Unit.

NOTE When selecting spindles, refer to the tables in the preceding chapters.

Viscosity/volume The following table lists the viscosity ranges and sample volumespossible with the Small Sample Adapter:

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Operating Instructions 1. Raise the viscometer unit to the top of its vertical stand and level theinstrument.

2. Use the thumbscrew toattach the Small SampleAdaptor (SSA) mountingbracket to the viscometer(see Figure 13).

3. Make sure that the O-ringseal on the bottom of theSSA is tight. Then loadthe sample chamber withthe required volume oftest material.

4. Slide the spindle (complete with thelink and coupling nut) into thechamber (see Figure 14) and securethe spindle to the viscometer shaft(see Figure 15) with the couplingnut (note the left-hand thread).

Figure 13: Attaching mounting bracket

Figure 14: Inserting spindle

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Figure 15: Attaching spindle to shaft Figure 16: Securing SSA

5. Align the pin on the SSA in the slot in the mounting bracket (seeFigure 16). Fix it into position using the thumbscrew.

6. Engage the slot in the end cap with the collar and turn to lock inposition (see Figure 17).

Figure 17: Attaching end cap Figure 18: Attaching hoses

7. Use the ports to attach hoses to the temperature bath (see Figure 18).

8. At the conclusion of the test, remove the end cap to clean the SSA.

Temperature Controlled Unit (98936-50/52)

When used with a Cole-Parmer®

98936 Series viscometer, the Tempera-ture Controlled Unit (TCU) provides asystem which will accurately measurethe viscosity of materials at precisetemperatures ranging from 5°C aboveambient to 260°C. The TCU is compat-ible with all 98936 Series viscometers.

Figure 19: The TCU oven(sketch includes viscometer and stand)

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The TCU contains an electronic controller which produces a proportion-ally-controlled power output to the heating element as the actual tem-perature approaches the set temperature. This provides precise tempera-ture control over a wide range of settings with minimum overshoot.

Specifications The specifications for the TCU are listed in the following table:

Spindles Spindles with coaxial cylinder geometry are available to allow measure-ment of viscosity at known shear rates. These special spindles aredesignated for use with particular 98936 Series instruments as indicated:

NOTE For TL and TR spindle order information please see pages 13 and 23.

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TCU installationBefore installing the TCU, make sure that your 98936 Series instrumentis full assembled (see previous chapters for instrument assembly).Consult your TCU manual for additional information.

1. Raise the viscometer to its highest point on the stand.

2. Use the adjustable feet on the base (and the bubble level on theviscometer) to level the viscometer. Tighten the clamp when theviscometer is level.

3. Attach the alignment bracket tothe rear of the viscometer cupusing the thumbscrew provided(see Figure 20).

Checking alignment 4. Place an empty sample cham-ber in the oven and attach thelargest spindle, using a 25 mm(1") link and coupling nut.

5. Lower the viscometer, makingsure that the alignment bracketengages with the guide pins ontop of the oven (see Figure 21).

6. If necessary, adjust the TCUposition relative to the mount-ing bracket to ensure that thespindle will be centered in thesample chamber.

TCU/controller connections 7. Connect the TCU oven to theHEATER POWER OUTPUTconnection on the controllerusing the cord attached to theoven (see Figure 22).

8. Attach the TCU Lemo plugconnector to the INT.PRT(Internal Platinum ResistanceThermometer) connection onthe controller.

9. Make sure that the TCU power switches are off and connect theelectronic controller to a power source using the cable provided.Attach the cable from the POWER INPUT connection on thecontroller to an outlet matching the power requirements listed on thebase of the TCU controller.

CAUTION Make sure the power connection includes a ground (earth) connection.

Figure 22: Attaching oven toelectronic controller

Figure 20: Attaching alignmentbracket to viscometer cup

Figure 21: Aligning guide pins

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TCU operation

WARNING When handling samples at high temperatures, you should wear gloves,protective eyewear and protective clothing. Use caution when testingsamples above their flash points. Viscosity measurements should becarried out in a well-ventilated area with precautions appropriate for thesample being tested.

Spindle selection With the viscometer at the top of the rack, select a spindle to suit theviscosity of the sample. Refer to the table below for spindle selectioninformation.

Procedure 1. With the melt containersupported in its stand (seeFigure 23), load a measuredsample into it (samples thatare solid at room tempera-ture should be weighed togive the correct liquidvolume). Do NOT exceedthe sample volumes shownin the table below. Figure 23: TCU melt container and

stand

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2. Place the loaded meltcontainer in the ovenusing the cell removaltool supplied (seeFigure 24).

3. Rotate the melt con-tainer until its baselocks in place in theTCU oven.

4. Attach the spindle andadapter to the long hookand insert the spindleinto the melt chamber(see Figure 25). If thesample is solid at roomtemperature, wait for itto liquefy (step 11)before inserting thespindle.

5. Screw the hook adapter(left-hand thread) to theviscometer shaft.

6. Lower the viscometeruntil the end of thealignment bracket isapproximately 2 mmabove the base of the guide pin on the oven.

7. Place the melt container plug on the melt container.

8. Switch the power input ON using the POWER switch and ensurethat the green POWER lamp is lit.

9. Switch the NORMAL/PROBE switch to NORMAL.

NOTE A separate HEATER switch is provided so that the unit can be used withthe sample heater on or off. The red HEATER lamp will light when theheater controller is on, and will flash when the control temperature isachieved.

Setting temperature 10. Place the READ/SET switch in the SET position, and rotate theSET TEMP control knob (clockwise to increase, counterclockwiseto decrease) until the display shows the required temperature.

NOTE The SET TEMP control knob is equipped with a dial lock to preventaccidental movement. Slide the lock up to rotate the control knob andslide the lock down to secure the SET TEMP control at the desiredsetting.

Figure 24: Placing melt containerin TCU oven

Figure 25: Inserting spindle

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11. Switch the heater to the ON position.

12. Place the READ/SET switch in the READ position. The display willnow show the oven temperature, which will rise (or fall) to the settemperature and stabilize.

NOTE When setting a low temperature (near room temperature), set to 10°Cbelow the required temperature and then increase the set temperaturegradually.

NOTE Moving the SET TEMP control knob will change the temperature settingat any time, regardless of the READ/SET switch position.

13. Wait approximately 30 minutes for the system to reach temperatureequilibrium.

14. Select the viscometer spindle switch position to suit the spindle inuse and turn the instrument on.

15. If OFF RANGE is indicated after a few revolutions of the spindle,reduce the speed.

16. Leave the viscometer running during the time required to reachequilibrium; this will reduce temperature gradients within thesample.

Equilibrium is reached when the viscometer display is repeating thesame value. Once equilibrium is reached, viscosity readings can be takenat different speeds.

Normal/Probe settingsA variable temperature gradient caused by thermal resistance existsbetween the internal block of the TCU oven, the melt container, and thesample itself. The farther the sample temperature varies from ambient,the larger the temperature value of the gradient. If using an externalprobe, measure the sample (rather than the block) temperature when thegradient is believed to be affecting viscosity calculations significantly.

Using the external probe The TCU is equipped with a toggle switch marked NORMAL/PROBE.In the NORMAL position, the display will show the SET and READvalues as described earlier. In the PROBE mode, the controller contin-ues with its set conditions, but the temperature display is switched to theexternal probe reading.

Probe connection The external probe should be connected to the plug labelled EXT.PROBE on the rear of the TCU chassis. When the toggle switch is in thePROBE position, the external probe temperature will then be displayed.

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Cooling procedureThe temperature of the oven canbe reduced by inserting thecooling plug in place of thesample chamber and passing tapwater through it (see Figure 26).

NOTE Water MUST be circulatingthrough the cooling plug forefficient cooling.

Cleaning the TCUIt is important that the meltcontainer and spindles are kept clean to avoid corrosion which couldcontaminate sample and affect viscosity readings.

Causes of corrosion Stainless steel is corrosion-resistant, but not corrosion-proof. Commoncauses of corrosion are noted below:

Halogen salts Halogen salts, including Chlorine, bromine, fluorine and iodine, willcause pitting of stainless steel.

Natural salts Even the natural salts in tap water can cause some pitting, depending onthe concentration, temperature, and length of exposure.

Water line corrosion Pitting and corrosion are most evident at the water line where oxygen isavailable. Corrosion occurs rapidly at elevated temperatures. Regularcleaning minimizes the damage.

Carbon embedding Imperfections in the stainless steel itself, such as microscopic pieces ofcarbon steel imbedded in the material, will cause surface rust to appear.This kind of rust can be wiped off but it will continue to reappear.

Evaporation Due to evaporation, water in a vessel tends to concentrate salts andimpurities to the point where the water becomes corrosive.

Calcium buildup/cleaning Tap water properties vary from one geographical area to another. Hardwater, well water, and even partially deionized water may contain heavycalcium deposits. The calcium will form scale on the sides of a vessel.Pitting can take place under the scale. Regular monthly scouring willclean off scale buildup and reduce pitting.

Distilled water Even distilled water is mildly acidic and somewhat corrosive, butstainless steel is usually affected only slightly.

Airborne contaminants If the viscometer is operated in a corrosive atmosphere, some of theairborne contaminants can be absorbed by materials being tested andform a corrosive solution that may damage the chamber. A corrosiveatmosphere may also cause the exterior finish and materials to deterio-rate. If the viscometer is exposed to a corrosive atmosphere, inspect theunit frequently.

Figure 26: Inserting cooling plug

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NOTE Failure of the product due to operation in a corrosive atmosphere is notcovered under the warranty.

Cleaning stainless steel With proper cleaning and maintenance, stainless steel will retain itscorrosion-resistant properties and bright appearance for years.

SAFETY Review the Material Safety Data Sheet(s) for the solvent(s) ordegreaser(s) being used, and take the appropriate safety precautions.

Make sure the unit is turned off, and that no other operating electricalequipment is nearby. Clean the viscometers (or spindles) in a well-ventilated area.

Cleaning procedure Follow the instructions below to perform regular cleaning.

CAUTION Review and observe the Material Safety Data Sheet (MSDS) for anysolvents or degreasers before using them to clean TCU components.

Clean the TCU in a well-ventilated area.

Always use tongs to remove the (hot) melt container and pour out thesample.

CAUTION Do NOT use chlorine-based cleaners or abrasives on the TCU.

For routine cleaning, use mild, soapy water and a damp cloth.

For stubborn spots, or to remove scale buildup, use a synthetic scouringpad or stainless steel wool (regular steel wool leaves particles that createrust spots on stainless steel).

Use a clean cloth rinsed in hot, clean water to wipe off any soapy resi-due. Use a clean, soft cloth to dry surfaces thoroughly. To remove greaseor oils, use an OSHA-approved vapor degreaser or solvent.

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CHAPTER

7 RETURNING A PRODUCT

Procedure Before returning a Cole-Parmer® product for repair or service, makeevery attempt to identify the problem.

Return of items Authorization must be obtained from our Customer Service Departmentbefore returning items for any reason. When applying for authorization,please include data regarding the reason for the return. For your protec-tion, items must be carefully packed to prevent damage in shipment, andinsured against possible damage or loss. Cole-Parmer® will not beresponsible for damage resulting from careless or insufficient packing. Arestocking charge will be made on all unauthorized returns.

NOTE The Cole-Parmer® Instrument Company reserves the right to makeimprovements in design, construction and appearance of productswithout notice.

WarrantyThe Cole-Parmer® Instrument Company warrants this product to befree from significant deviations in material and workmanship for aperiod of one year from date of purchase. If repair or adjustment isnecessary and has not been the result of abuse or misuse within the oneyear period, please return—freight prepaid—and correction will be madewithout charge. Cole-Parmer® alone will determine if the productproblem is due to deviations or customer misuse.

Out of warranty products will be repaired on a charge basis.

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i CONTENTS - Cole-Parmer · 2016. 11. 15. · components of the viscometer, immediately turn off the unit, discon-nect the viscometer from the power supply and contact Cole-Parmer®.

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