Berthold LB 444 K-40 Operating instructions

Potassium Content

Measurement

LB 444 K-40

ID No. 55884BA2

Rev. Nr.: 00

01/10 347LB 444 K-40

I

Operating Manual Potassium Meter

LB 444 K-40

Contents

1 GENERAL INFORMATION ..................................................... 1

2 OVERVIEW........................................................................... 2

3 SYSTEM DESCRIPTION......................................................... 4

4 INSTALLATION OF THE DETECTORS..................................... 5

4.1 Selection of the Measuring Site .............................................................. 5

4.2 Installation of the Detector LB 5430 on a Bunker................................... 6

4.3 Installation of the Detector LB 5402 in a Bunker.................................... 7

4.4 Measurement in a Pipe ........................................................................... 7

4.5 Measurement on a Conveyor Belt ........................................................... 9

4.6 Installation of the Evaluation Electronics ............................................. 10

4.7 Installation of the Detector .................................................................. 10

4.7.1 Installation in a Container .............................................................. 10

5 CONNECTIONS................................................................... 11

5.1.1 Evaluation Unit LB 444 K-40........................................................... 11

5.2 Evaluation Unit LB 444 K-40 ................................................................. 13

5.2.1 General Description....................................................................... 13

5.2.2 Display........................................................................................ 13

5.2.3 Keypad Function ........................................................................... 13

5.2.4 Softkeys...................................................................................... 14

5.2.5 Menu Structure............................................................................. 14

5.2.6 Menu Potassium Content Measurement ............................................ 15

6 SOFTWARE FUNCTIONS AND SYSTEM CONFIGURATION ... 19

6.1 General Data......................................................................................... 19

6.2 Operating Mode .................................................................................... 20

6.3 Parameter............................................................................................. 21

6.4 Product Data......................................................................................... 23

6.5 Calibrate............................................................................................... 24

6.6 Live Display .......................................................................................... 26

6.7 Service Menu ........................................................................................ 26

7 GETTING STARTED............................................................. 27

7.1 Quick Installation Overview.................................................................. 27

7.2 Getting Started..................................................................................... 28

7.2.1 Basic Settings............................................................................... 28

7.2.2 Calibration ................................................................................... 29

7.2.3 Checking the Calibration ................................................................ 31

7.3 Live Display .......................................................................................... 31

7.4 Correcting the Results: Addition and Multiplication .............................. 32

7.4.1 Additive Constant.......................................................................... 32

7.4.2 Multiplication Factor ...................................................................... 32

7.5 Automatic Measuring Time Switchover................................................. 33

7.6 Batch Measurement.............................................................................. 34

7.7 Radiating Interference Detection.......................................................... 35

7.8 Error Messages ..................................................................................... 36

7.8.1 Acknowledging Error Messages ....................................................... 36

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7.8.2 Error Messages during Operation .................................................... 36

7.8.3 Error Messages during Calibration ................................................... 36

7.8.4 Error Messages during Measurement ............................................... 37

7.9 System Start/Stop................................................................................ 39

8 TECHNICAL DATA ...............................................................40

8.1 Evaluation Unit LB 444 K-40................................................................. 40

8.2 Detectors.............................................................................................. 41

9 SERVICE INSTRUCTIONS....................................................42

9.1 General Safety Precautions................................................................... 42

9.2 Evaluation Unit LB 444 K-40................................................................. 42

10 SERVICE.............................................................................44

10.1 Service Menu Overview ........................................................................ 44

10.2 Service Menu ........................................................................................ 46

10.2.1 Plateau Check .............................................................................. 47

10.3 Detector ............................................................................................... 50

10.3.1 Checking the Crystal-Multiplier Assembly ......................................... 50

10.3.2 Testing and replacement of the photomultipliers in the detector LB 543051

10.4 Replacing the Evaluation Unit LB 444 K-40........................................... 52

10.5 Setup Protocol...................................................................................... 53

11 DIMENSIONAL DRAWINGS.................................................55

11.1 LB 5402 ................................................................................................ 55

11.2 LB 5430 ................................................................................................ 55

11.3 LB 444 K-40.......................................................................................... 56

01/10 347LB 444 K-40

III

Operating Manual

Potassium Meter

LB 444 K-40

Issue

No. Date Comments

1 01.01.10 First edition

01/10 347LB 444 K-40

1

1 General Information

Safety Summary

Electrical Shock Hazard

Disconnect power to ensure that contact with energized part is avoided during installation

and servicing.

Specific Warnings

Never change the installation or the parameter settings without a full knowledge of the

relevant part of this manual, the connected controller and the process, if it is controlled

by this measuring device.

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2 Overview

The Potassium Meter LB 444 K-40 is designed for measurements of the concentration of

potassium in bulk materials, suspensions and solutions.

The concentration of potassium in bulk materials or liquid solutions is measured by

detecting gamma radiation of the natural isotope K-40. This isotope is contained in

natural potassium in a constant percentage (0.0119%). As the isotope K-40 decays, it

emits gamma radiation with an energy of 1.46 MeV.

The detector LB 5430 detects radiation using an organic scintillator (PVT), the detector

LB 5402 using a NaI crystal. The radiation triggers tiny flashes of light in the scintillator

which are converted into electrical pulses by the photomultiplier. The count rate of this

radiation is a direct measure for the potassium concentration. In addition, the scintillation

detector responds to radiation emitted from the environment, for example, the walls and

the floor which are covered with a layer of potassium.

Further radiation is generated by incident cosmic rays at the location of the detector.

Background radiation remains more or less constant for each installation within a plant,

provided the location is not changed. To keep the statistical error of the measured result

as small as possible, the scintillation detector, fixed at the outside of a bunker or below a

belt conveyor, is shielded against background radiation by an additional lead shielding.

If the scintillation detector is inserted into bulk material, solutions or suspensions inside a

protection tube, the material itself is acting as a shielding against the background

radiation.

Potassium can be found predominantly in the form of KCl. However, to this day the unit K2O is

still used in many companies. The evaluation unit LB 444 K40 allows the calibration and

measurement in both units. Important: the calibration and measurement have must be

performed in the same unit. The following details for “K20” also apply for “KCI”.

There is a linear relationship between the count rate measured by the scintillation

detector and the potassium concentration.

This relationship can be expressed as follows:

K = a (N - N0) (1)

where:

N

0 = count rate measured by the scintillation detector if the bulk material or the

liquid contains 0% K2O.

“N” = count rate detected by the scintillation detector at a concentration “K” of K2O.

“K” = concentration of K2O.

“a” = reciprocal value of the count rate per % K2O.*

* This value can also be understood as the slope of the linear function. The term a x N0

is the background expressed as a percentage of K2O.

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The hardware and software of the LB 444 K-40 system makes it easy to adapt the

system to rather different measuring geometries and measuring tasks. Therefore, the

settings and parameters of the measuring instrument have to be defined with care for

the respective measuring task when taking the system into operation. Important

parameters may not be changed later, in order not to compromise the reliable operation

of the system. The system should be taken into operation and settings changed only by

persons who know how to work with the instrument. Therefore, all users should read

these operating instructions carefully. We recommend documenting all settings in a setup

protocol.

Before starting any work, please read this operating manual carefully!

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3 System Description

The system is comprised of the following components:

Figure 1: Measuring system with LB 5430 detector

a) Detector LB 5430 for installation on the outside of the container or

b) LB 5402 for installation in a protective pipe inside the container

c) Connection cable

d) Evaluation unit LB 444 K-40

A 19” rack can be supplied for installation of up to 4 devices or a protective housing for

two devices for installation of the evaluation unit.

The device LB 444 K-40 with a software that has been expanded for potassium

content measurements is used as evaluation unit. The functions of the density

measurement are still available. This operating manual describes only those

functions that are relevant to the potassium content measurement.

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4 Installation of the Detectors

4.1 Selection of the Measuring Site

Assuming a homogeneous mixture of potassium in the material to be measured, the

number of K-40 isotopes increases with increasing amount of material. This means that

the count rate of the detector rises when the amount of material in front of the detector

rises, although the material contains a constant percentage of the K-40 isotope.

The radiation is partially absorbed between its point of origin and the detector.

Consequently, material that is farther away from the detector does not contribute much

to the result. If the material thickness in front of the detector is increased, or the

detector is surrounded by material, the count rate will reach a saturation value and does

not rise anymore even if the thickness of the material layer still increases. This material

thickness is called saturation thickness which is expressed as follows:

d = 100/ρ cm,

where ρ is the density of the bulk material in g/cm3.

Example: For a potassium sample with a bulk weight of 1.2 g/cm3 the saturation

thickness necessary for the measurement would be 100 cm /1.2 = 83 cm.

This means, for a surface probe, the inner diameter of a bunker should be

about 83 cm; a dip probe should be inserted in the center of a bunker having

an inner diameter of at least 166 cm.

These conditions ensure that the measured value is independent of bulk density

variations.

If this conditions cannot be fulfilled, one has to

calculate if the errors that occur as a result of a

smaller volume and a possible change of the bulk

weight or the density are still acceptable.

The goal of a continuous measurement of the K20

content is to cover the detection device with the total

amount of material to be measured, i.e. the position

of the scintillation detector has to be selected such

that the surrounding material thickness is not much

thicker than the saturation thickness.

If this is not the case the material being further away

from the detector than the saturation thickness would

not contribute to the measurement and therefore its

potassium content would not be taken into account

(see Figure 2).

Provided the product to be measured shows a

homogeneous structure, no measurement errors will

occur.

Figure 2: Saturation layer

S = saturation layer thickness

1 = measured material layer

1

2

S

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2 = material not covered by the measurement

4.2 Installation of the Detector LB 5430 on a Bunker

The LB 5430 detector is installed on the outside wall of a bunker. Typically, it is fixed to

the flange of the detector.

Figure 3: Detector LB 5430

Depending on the version, the detector weights approx. 60 – 70 kg. Please take this

weight into account in your planning.

All screws and mounting parts have to be secured such that they cannot come loose

during operation, so that the detector cannot fall down.

The detector must not be subject to heavy mechanical vibrations. If extreme vibrations

are likely to occur at the installation site, the detector has to be mounted on a damping

and shock absorbing arrangement.

Care must be taken that no potassium containing material may be deposited between the

surface probe and the outside wall. This would result in measurement errors.

The ambient temperature at the installation site of the detector must not exceed 50°C. If

the bunker wall is hot (>50°C), you may insert a suitable insulating plate having a

thickness of approx. 20 mm between the container wall and the detector or use a

detector with water cooling.

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4.3 Installation of the Detector LB 5402 in a Bunker

The detector is installed into a protective pipe, front side closed, and inserted into a

bunker. The distance of the material surface in front of the detector head sensitive to

radiation (position of the scintillation crystal) should on all sides correspond to the

calculated saturation thickness.

If hot liquids are used a cooling water jacket for

the probe is necessary.

The detector temperature must never

exceed 50°C.

No crystallization must occur on the protective

pipe. If necessary, the protective pipe has to be

provided with a thermal insulation and possibly

with a heating jacket.

Crystallizations would significantly falsify the

measured results, since the potassium

concentration in the crystallized layer is

typically higher than in the liquid solution.

S = saturation layer thickness

1 = measured material layer

2 = material not covered by the measurement

Figure 4: Measurement in a container

4.4 Measurement in a Pipe

When measuring in a pipe, the saturation layer thickness is usually not achieved or at

least not achieved in all directions. In the case of large pipes, the saturation layer

thickness is usually achieved in the longitudinal direction of the pipeline, However,

transverse to the pipeline axis, the saturation layer is not always achieved. This can have

an effect on the measurement result, which is larger:

a) the smaller the pipe is

b) the stronger the density varies in the pipeline, (see Figure 6).

The measurement of the saturation thickness is also affected by the diameter of the pipe,

the pipe material and the wall thickness of the pipe.

A correction of the influence is possible in some cases by an additional density

measurement.

This will require an extended period of time for the recording of

a) Density values

b) Displayed K2O values and

c) the appropriate, K2O values determined in the laboratory.

01/10 347LB 444 K-40

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A correction function can then be calculated from these values.

Figure 5: Measurement in a pipeline

Potassium measurement. Saturation thickness for different densites resp.

bulk densities

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600 700 800 900 1000

Layer thickness in mm

cps in %

Density =1,0

Density =1,2

Density =1,4

Figure 6: Influence of thickness and

density

Installation:

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The detector should be mounted in a horizontal pipeline at the top or side. This will

prevent that the measurement is influenced by any deposits on the ground of the

pipeline.

4.5 Measurement on a Conveyor Belt

Normally, the required saturation thickness cannot be reached on a conveyor belt, so the

measured result will be influenced by changes of the bulk weight and/or changes of the

material layer thickness.

However, if it is ensured that

• variations of the bulk weight in the material cannot occur (uniform grain size)

• the height of the material layer is kept constant by leveling device.

a measurement can also be carried out on a conveyor belt. However, the measurement

error is larger than with measurements in a bunker.

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4.6 Installation of the Evaluation Electronics

The evaluation unit (protection type IP 20) can be installed in a 19” rack. This rack then

has to be installed into a suitable measurement cabinet.

The wall housing can be fixed directly to a wall using screws. For outdoor installation, you

may have to install a sunshield to protect the evaluation unit against solar heating.

4.7 Installation of the Detector

Use a water cooling jacket to protect the detector against temperatures > 50°C.

Cables have to be protected against temperatures > 70°C.

Measuring system installed outdoors have to be protected from rain and direct sunshine

by a canopy. The cable entry must not be exposed to temperatures exceeding 70°C. The

cable gland and the cable entry must be aligned such that no water can flow along the

cable into the connection box.

The detector installation site must not be subject to heavy vibrations as this could

damage the detector.

Samples have to be taken for calibration of the measurement. A sampling point has to be

foreseen in the direct vicinity of the measuring site.

4.7.1 Installation in a Container

If the detector is installed in a protective pipe inside the

container, the protective pipe has to be sealed to prevent

the penetration of dust and humidity. The detector

includes two suspension eyes. Wire ropes can be attached

to these suspension eyes. It is not permitted to suspend

the detector on the cable.

The cable should form a loop to allow possibly penetrating

water to drip off.

Figure 7: Installation of de-

tector in a protective pipe

Suspension

eyes Loop

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5 Connections

The power supply of the detector and the transfer of the measured values and important

information to the evaluation unit LB 444 K-40 takes place via a two-wire screened cable.

The possible cable length is dependent on the cross-section of the connection cable used.

The cable entry at the detector

permits a cable diameter of 6-10

mm.

5.1.1 Evaluation Unit LB 444 K-40

c a

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

Relay 2

Relay 3

Relay 1

Mains

2(-) 1 (+)

Probe

RS 485

0/4 - 20 mA

LB 444

Voltage

selection

Fuses

Dig. IN 1

Dig. IN 2

Dig. IN 3

4

6

8

Distanzpart

1

2

Connect cable on the

rear panel of the

evaluation unit as shown

in the wiring diagram in

the appendix to this

manual.

Figure 8: Terminal connection evaluation unit (rear panel)

Connect the device only to the appropriate line voltage.

All safety previsions regarding the power distributor have to be observed.

The evaluation units do not include a separate mains switch. A separate

safeguarding and easily accessible shut-down have to be foreseen.

The device must not be installed in explosive hazardous areas.

Refer to the wiring diagram in the appendix to this manual regarding the connections.

cross-section in mm² Max. cable length in m

1 1000

1.5 1500

2.5 2500

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Detector (2a/2c)

Relay 2 (12a/12c)

The relay can be set for the following functions:

Min. – Alarm, Max. – Alarm, Detector temperature,

Relay 3 (4a/14c)

Functions:

Min. – Alarm, Max. – Alarm, Detector temperature,

Relay 1 (16a/16c)

The relay is used to indicate errors. The contact opens in case of error.

External product selection

Digital input 1 (18a/18c)

Digital input 2 (20a/20c)

Calibration data of up to 4 different products can be defined in the evaluation unit LB 444

K-40. These data sets can be selected via digital inputs.

External Start/Stop Signal (22a/22c)

Option to interrupt measurement for the following special applications:

- Start/Stop in batch mode

- Stop of continuous measurement, e.g. to suppress unexpected malfunctions

0/4-20mA (26a+/26c-)

Isolated current output for measured value, max. load 500 Ω.

Current input (28a-/28c+)

Product temperature for temperature compensation (usually not needed for potassium

content measurements).

Power supply (30a/30c)

Power supply 115V/230V AC or 24 V AC/DC depending on power supply unit (see

label on instrument rear pane!).

Fuses

To replace fuses, you have to open the fuse holder with a screw-driver. Observe fuse

type and rating!

Before turning on the power supply, carefully check all connections once more to rule out

any damage to the instruments.

RS 232

Port for data transfer from evaluation unit to printer or PC (front panel of evaluation

unit).

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5.2 Evaluation Unit LB 444 K-40

5.2.1 General Description

The evaluation electronics is

designed as a 19” module in

the format 3 HE, 21 TE. It

includes the microprocessor-

controlled evaluation electro-

nics and the power supply

for the required operating

voltage. A 32 bit microproc-

essor is used for signal

processing.

enter

clear run

BERTHOLD

LB 444 - 1 V 1.0

Density -Meter more

enter enter

enter

clear run

LCD display

Softkeys

Function keys

Figure 9: Operating elements of the evaluation unit

The instrument is operated via six foil keys:

Three keys work as softkeys which allow user-guided definition of all instrument settings

and input of the required parameters.

Three more keys serve as function keys.

The front panel includes a RS 232 interface port. Data can be transferred to a PC using a

terminal program.

The terminal strip on the instrument rear panel includes all terminals for power supply,

for the detector, and for the analog and digital output signals. The current output is

isolated. The built-in relays for max.-min.-indication and for error messages include an

isolated contact.

System malfunctions are signaled by error messages.

Calibration data is stored in a FLASH memory and saved, so they will not be lost in case

of power failure.

5.2.2 Display

The instrument’s illuminated display comprises four lines. The first three lines show the

menu titles, the currently selected parameters or the current measurement value. The

bottom line shows the current function of the respective softkey button. If a measure-

ment is running, the “run” status is displayed.

5.2.3 Keypad Function

The Potassium Meter is operated via the softkeys and function keys described below.

With these keys you can select the operating level you want within a menu structure in

order to select a function or enter parameters.

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5.2.4 Softkeys

Softkeys are used to select different menu groups and operating levels within the menu

structure. Depending on the current position in the menu structure, functions are

assigned to these keys, as shown on the display above the respective key.

5.2.5 Menu Structure

The menu structure is illustrated on the following pages. Push <more> to select the

various menu groups. From there you get to the respective menu by pushing <sk1> or

<sk2>. Within the menu, push <more> to go to the individual windows and at the end

of the menu push <done> to return to the menu group.

sk1 and

sk2 Go to the indicated menu

more Go to next display or menu group

done Shows the end of the menu and

takes you back to the menu group

^^^

T

ext: scrolls through the various

selection options

Numerical values: increments the

number marked by the cursor by 1

 Moves the cursor to the left and at

the end of the input field again to the

start position

+ and - Scrolls forward / back in a result list

or in the live display

Figure 10: Softkey functions

sk1: General Data

sk2: Operating Mode

sk1 sk2 more

Relay 2

Minimum 50%

Hysteresis 5%

<-<-<- ^^^ mo re

Time constant

Value 20s

^^^ <-<-<- more

HV (500): 20/s

HV (560): 123/s

HV (560): 620/s

+ - exit

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Berthold LB 444 K-40 Operating instructions

Berthold LB 444 K-40 Operating instructions

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