kd2 manual.pdf

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D e ca g o n D e v i ce s , I n c .

KD2

Users Manual

version 1.0

Thermal PropertiesAnalyzer


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2001 D ecagon D evices, Inc.

All rights reserved.

D ecagon D evices, Inc.950 NE Nelson Court

P.O . Box 835

Pullman WA 99163


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K D2 Users Guide

Table of Contents

i

Contents

1. Introduction . . . . . . . . . . . . . . . . . .1About the KD2 . . . . . . . . . . . . . . . . 1KD2 Specifications . . . . . . . . . . . . 2

Contact Information . . . . . . . . . . . 2Warranty Information . . . . . . . . . 3Sellers Liability . . . . . . . . . . . . . . . 3

2. Operation . . . . . . . . . . . . . . . . . .5Turning it on . . . . . . . . . . . . . . . . . . 5Taking Measurements . . . . . . . . . 6How the KD2 takes measurements 11

3. Care and Maintenance . . . . . . .13Cleaning . . . . . . . . . . . . . . . . . . . . . 13Battery Replacement . . . . . . . . . . 13Caring for the Probe . . . . . . . . . . 15

4. Theory . . . . . . . . . . . . . . . . . . . . .16

Declaration of Conformity . . . . . .22


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Table of Contents

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K D2 Users Guide

Introduction

1

1. Introduction1. Introduction1. Introduction1. Introduction

Welcome to your new K D 2 T hermal Proper-

ties Analyzer. T his guide is designed to help

you understand and use your instrument to

the best of its capabili ty.

About the KD2

T he K D 2 is a compact, portable meter used to

measure thermal properties. I t consists of ahand-held readout and a single-needle sensor

that can be inserted into the medium you

wish to measure. A reading is initiated by

pressing the left button on the readout. The

controller waits for 90 seconds to ensure tem-perature stability, then heats the probe for 30

seconds. At the end of the reading, the con-

troller computes the thermal properties based

on the measurements made during the heat-

ing period of the probe. T his data is used tocalculate thermal conductivity, thermal resis-

tivity, and thermal diffusivity. Further details

about the measurements and how theyre


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Introduction

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made are given in chapters 2 and 3 of this

guide.

KD2 Specifications

Measurement Speed: 2 minutesAccuracy: 5% T hermal Conductivity/Resistivity

10% T hermal D iffusivity

Power: 3.0V CR2-type li thium-ion batteryWeight: 148g (5 oz.)Operating Environment: 5 to 40CRange of Measurement:

K ( thermal conductivity) : 0.1 2 Wm-1C-1

D ( thermal diffusivity) : 0.1 1.0 mm2s-1

R ( thermal resistivity) : 0.5 10mC W-1

Sensor:

Needle length: 60mm Needle diameter: 0.9mm

Cable length: 72cm

Contact Information

I f you need to contact D ecagon for customer

support or any other questions, you can reach

us by any of the following:

Email us at [email protected]


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K D2 Users Guide

Introduction

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Send us a fax at: (509) 332-5158

Call us at: 1-800-755-2751 ( US and Can-ada only) or 509-332-2756.

Warranty Information

T he K D 2 has a 30-day satisfaction guarantee

and a one-year warranty.

Sellers Liability

Seller warrants new equipment of its own

manufacture against defective workmanship

and materials for a period of one year from

date of receipt of equipment ( the results ofordinary wear and tear, neglect, misuse, acci-

dent and excessive deterioration due to corro-

sion from any cause are not to be considered

a defect) ; but Sellers liabili ty for defective

parts shall in no event exceed the furnishingof replacement parts F.O .B. the factory where

originally manufactured. M aterial and equip-

ment covered hereby which is not manufac-

tured by Seller shall be covered only by the

warranty of its manufacturer. Seller shall notbe liable to Buyer for loss, damage or injuries

to persons ( including death) , or to property

or things of whatsoever k ind ( including, but


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KD2 Users Guide

Introduction

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not without limitation, loss of anticipated

profits) , occasioned by or arising out of theinstallation, operation, use, misuse, nonuse,

repair, or replacement of said material and

equipment, or out of the use of any method

or process for which the same may be

employed. The use of this equipment consti-

tutes Buyers acceptance of the terms set forth

in this warranty. There are no understandings,

representations, or warranties of any k ind,

express, implied, statutory or otherwise

( including, but wi thout limitation, the implied

warranties of merchantability and fitness for aparticular purpose) , not expressly set forth

herein.


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K D2 Users Guide

Operation

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2. Operation2. Operation2. Operation2. Operation

The K D 2 is designed to be a simple, easy to

use instrument that will allow you to make

quick and accurate thermal properties mea-

surements. Following are some instructions

on how the instrument functions.

Turning it on

To turn on the K D 2, press the left button ( I)once. T he LCD display wi ll appear, showing

the previous measurement taken.

Wm-11 C -11

2 3.0 C |


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Operation

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Taking Measurements

The K D 2 measures thermal conductivi ty,resistivity, and diffusivity at the same time

from one measurement, but can only display

one reading at a time after the measurement

is made. T he right ( II) button is used to tog-

gle through the calculated readings after themeasurement has been made. To begin a

measurement, press the left ( I) button to turnon the instrument. T he instrument will be in

the same measurement mode as it was when

it was last used ( thermal conductivity, thermal

diffusivi ty, or thermal resistivi ty mode) and

will display the last reading taken.

NOTE!:I t i s impo r tant to w a i t fo r abou t 5

mi nutes betw een r ead i ngs i f th e p r obe i s

lef t i n the same locat i on!If multiple mea-surements of a sample are made too rapidly

in succession, the samples temperature will

not have had enough time to equilibrate from

the previous reading, and the resulting mea-

surement will be inaccurate. For best results,the sample should be as close to equilibrium

as possible. A n ideal environment for equili-

bration can be accomplished by placing the


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K D2 Users Guide

Operation

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K D 2 probe and sample in an isothermal

chamber or styrofoam box.

How to Start the Measurement

O nce the instrument is on, do the following:

1. Carefully insert the probe into your

medium.

2. Press the left button to begin the mea-

surement process. The instrument will

fi rst equilibrate for 90 seconds. During

this time you will be able to see that it is

equilibra ting by the blinking hourglassicon below the value. The temperature

measured by the probe will be displayed

in the lower right corner of the screen:

Wm-11 C -11

2 0.0C

hourglass icon temperature


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Operation

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Note!:Make sure to watch the tempera-

ture du ring the equi li bration stage tomake sure i t doesn t drastically fluctuate

or rapidly change. If the temperatu re is

sti ll rapidly changing, pu ll the probe ou t

of the sample and wai t un ti l the sample

temperatu re is stable before measuring

again.

3. After equilibrating, it begins its 30-second

heating and measurement cycle. D uring

this stage of measurement you will see a

blink ing thermometer icon appear, andthe temperature reading will increase:

4. When the reading is finished, the check-

ered finish line flag will blink on the

screen, and a final reading will be dis-

Wm-11 C -11

2 7.0 C |

thermometer icon


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K D2 Users Guide

Operation

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played along with the sample tempera-

ture:

Thermal Conductivity

To display the measurement in terms of ther-

mal conductivity, press the right ( II) buttonuntil the thermal conductivity is displayed in

Wm-1C-1 ( watts per meter-degree Celsius) :

Wm-11 C -11

2 3.0 C |

finished icon

Wm-11 C -11

2 3.0 C |


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Operation

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Thermal Resistivity

To display the measurement in terms of ther-mal resistivity, press the right (II) button untilthe thermal resistivity is displayed in mC W-1

( meter-degrees C per watt) :

I f the value shown for thermal resistivity is

9.99, this indicates that your sample is out of

range for the K D 2 to measure.

Thermal Diffusivity

To display the measurement in terms of ther-

mal diffusivity, press the right ( II) button until

m C W-1

2 0.0C |


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K D2 Users Guide

Operation

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the thermal diffusivity is displayed in mm2 s-1

( square millimeters per second) :

Turning it off

The K D 2 will shut off automatically after 5

minutes of inactivi ty. To turn it back on, press

the left ( I) button once.

How the KD2 takes measurements

The K D 2s sensor needle contains both a

heating element and a thermistor. T he con-

troller module contains a battery, a 16-bit

microcontroller/AD converter, and power

control circuitry.

When you begin a measurement, the micro-controller waits for 90 seconds for tempera-

ture stabili ty, then applies a known amount of

current for 30 seconds to a heater in the

mm2

s-1

2 0.0C |


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KD2 Users Guide

Operation

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probe that has an accurately known resis-

tance. The microprocessor calculates theamount of power supplied to the heater. The

probes thermistor measures the changing

temperature for 30 seconds while the micro-

processor stores the data. At the end of the

reading, the controller computes the thermal

conductivity and diffusivity using the change

in temperature (T ) vs. time data. T hermalresistivity is computed as the reciprocal of

thermal conductivity.


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K D2 Users Guide

Care and M aintenance

13

3.3.3.3. Care and MaintenanceCare and MaintenanceCare and MaintenanceCare and Maintenance

Your K D 2 should require a minimum amount

of maintenance. Following are instructions for

cleaning and battery replacement, as well as

considerations for the K D 2 probe.

Cleaning

The K D 2s controller is stainless steel. I f it

needs cleaning, do so with a damp cloth. Donot immer se i t i n w ater . Clean the LCD

readout with a soft, damp cloth moistened

with water or a glass cleanser. D o not use tis-

sue or other wood-based fibers, as they can

scratch the plastic LCD screen.

Battery Replacement

The K D 2 uses a 3.0V CR-2 type Lithium-ion

battery. I t typically should last for about 1000

measurements. I f the battery charge is gettinglow, a low-battery indicator icon will appear

in the lower right corner of the LCD screen

when the heater comes on ( an occasional low


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KD2 Users Guide


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battery indication does not necessarily mean

the battery needs replacing) :

I f this screen appears continually, do the fol-

lowing to replace the battery:

1. Unscrew the small screw on the back ofthe K D 2 case.

2. Lift the back shell off to reveal the bat-

tery:

Wm-11 C -11

2 0.0C

+

|

locationbattery


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K D2 Users Guide


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3. Remove the battery and replace it with

the new one, making sure to orient thebattery the same way you removed it.

Caring for the Probe

The K D 2 sensor contains a heater and ther-

mistor that are essential for the function of the

instrument. Care should be taken to prevent

bending the probe. The probe itself is stain-

less steel, so it may be cleaned with a wet

cloth or sponge if it becomes dirty.


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KD2 Users Guide

Theory

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4.4.4.4. TheoryTheoryTheoryTheory

K D 2 calculates its values for thermal conduc-

tivity ( K ) , resistivity ( R) , and diffusivity ( D ) by

monitoring the dissipation of heat from a line

heat source given a known voltage.

The equation for radial heat conduction in a

homogeneous, isotropic medium is given by

( 1)

where Tis temperature ( C) , tis time ( s) , isthermal di ffusivity (m2 s-1), and ris radial dis-

tance (m) . When a long, electrically heated

probe is introduced into a medium, the rise in

temperature from an initial temperature, T 0, at

some distance, r, from the probe is

+

=

r

Tr

r

T

t

T 12

2


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Theory

17

( 2)

where qis the heat produced per unit lengthper unit time (W m-1) , h is the thermal con-

ductivi ty of the medium ( W m-1c-1), and Eiis

the exponential integral function

( 3)

with a = r2/4tand is Euler's constant( 0.5772 ) . When tis large, the higher order

terms can be ignored, so combining Eqs. ( 2)

and ( 3) yields

( 4)

I t is apparent from the relationship between

thermal conductivity and T = T-T0, shown in

=t

rEi

qTT

h 44

2

0

( ) ( ) ...844lnexp

12

222

+

+

=

=

t

r

t

r

t

r

duuuaEi a

( )

4lnln

4

2

0

rt

qTT

h


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Theory

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Eq. ( 4) , that Tand ln(t)are linearly related

with a slope m = (q/4h). Linearly regress-ing Ton ln(t)yields a slope that, after rear-

ranging, gives the thermal conductivity as

( 5)

where qis known from the power supplied

to the heater. T he diffusivity can also be

obtained from Eq. (4) . T he intersection of the

regression line with the taxis (T = 0) gives

(6).

From the calculated t0( from the intercept of

T vs. ln(t)) and finite r, Eq. ( 6) gives the dif-fusivity.

Because the higher order terms of Eq. ( 3)have been neglected, Eq. (4) is not exact.

H owever, if the slope and intercept are com-

puted only for T and ln(t)values, where tis

m

qh

4

( )

+=

4lnln

2

0

rt


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K D2 Users Guide

Theory

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large enough to ignore the higher order

terms, Eq. (5) and ( 6) give correct values forhand . To verify these relationships, realis-tic values ofhand were supplied to Eq.( 2) , varying both hand volumetric heat

capacity (cp) , and the resulting slope andintercept tabulated for tranging from 1 to 30

s. Plots of slope vs. theoretical hand

ln( intercept) vs. ln( theoretical ) show anexact linear relationship ( Fig. 1 and 2, respec-

tively) with low cross-covariance.

Figure 1: calcu latedhvs. theoreti calh


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Theory

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Figure 2: calcu latedvs. theoretical

The experimental analysis differs from the

theoretical shown in Eq. ( 2) in that the heaterand sensor have their own conductivity and

diffusivity, which, in general, differ from

those of the medium being measured. We

have shown experimentally that the relation-

ships in Eq. ( 5) and (6) sti ll allow calculations

ofhand , but empirical factors must beintroduced to correct for heater thermal prop-

erties.


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Theory

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Assumptions: The thermal conductivi tymeasurement assumes several things: thelong heat source can be treated as a infinitely

long heat source, the medium is both homo-

geneous and isotropic, and a uniform initial

temperature, T0

. A lthough these assumptions

are not true in the strict sense, they are ade-

quate for accurate thermal properties mea-

surements.


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KD2 Users Guide

Declaration of Conformity

22

Declaration of ConformityDeclaration of ConformityDeclaration of ConformityDeclaration of Conformity

Application of CouncilD irective: 89/336/EEC

Standards to which EN55022:1987

conformity is declared: EN500082-1:1992

M anufacturers Name: D ecagon Devices, Inc.

950 NE Nelson Court

Pullman WA 99163 USA

T ype of Equipment: T hermal Properties M eter

M odel Number: K D 2

Year of First M anufacture: 2001

This is to certify that the K D 2 T hermal Prop-

erties M eter, manufactured by D ecagon

D evices, Inc., a corporation based in Pullman,

WA, USA meets or exceeds the standards for

CE compliance as per the Council D irectives

noted above. All instruments are built at the

factory at D ecagon and pertinent testing doc-

umentation is freely available for verification.


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K D2 Users Guide

Index

23

Index

Aaccuracy 2

Bbattery

replacing13type 13

CCE

compliance 22cleaning 13

contact information2

DD (diffusivity)16

Eemail 2


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Index

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F

fax number 2

KK (thermal conductivity)16KD2

overview 1specifications2

L

low battery indicator 13

Mmaintenance 13measurement

method 11measurement range 2

O

off(turning off)11on(turning on)5operation


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Index

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on5

Pprobe

maintenance15specifications2

RR (thermal resistivity)16range 2

Ssellers liability 3specifications2

Ttelephone number 2temperature equilibrium6theory 16

assumptions21thermal conductivity

calculation18


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Index

thermal diffusivity

calculation18units11

thermal resistivitycomputed 12units10

Uunits

thermal diffusivity 11

thermal resistivity 10

Wwarranty 3

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