Computer Controlled Chemical Reactors Teaching Equipment

Computer Controlled Chemical Reactors
Teaching Equipment
Instruction Manual
CEXC
ISSUE 9
August 2014
Table of Contents
Disclaimer ................................................................................................................... 1
Copyright and Trademarks ...................................................................................... 1
General Overview ....................................................................................................... 2
Equipment Diagrams................................................................................................... 3
Important Safety Information....................................................................................... 4
Introduction.............................................................................................................. 4
Water Borne Hazards .............................................................................................. 4
Electrical Safety....................................................................................................... 5
Hot Surfaces and Liquids ........................................................................................ 5
Chemical Safety ...................................................................................................... 5
Description .................................................................................................................. 6
Overview.................................................................................................................. 6
Chemical storage bottles ......................................................................................... 6
Feed pumps............................................................................................................. 6
Stirrer....................................................................................................................... 7
Hot water circulator.................................................................................................. 7
Temperature control of the reactor .......................................................................... 7
Conductivity measurement of the reactor contents ................................................. 8
Reactor attachment ................................................................................................. 8
Mains plate at rear of the plinth ............................................................................... 9
Installation ................................................................................................................. 10
Advisory................................................................................................................. 10
Electrical Supply .................................................................................................... 10
Installing the PC Software ..................................................................................... 10
Installing the Equipment ........................................................................................ 11
Electrical Wiring Diagram ...................................................................................... 13
Operation .................................................................................................................. 14
Operating the PC Software.................................................................................... 14
Operating the Equipment....................................................................................... 14
ii
Table of Contents
Equipment Specifications.......................................................................................... 19
Overall Dimensions ............................................................................................... 19
Environmental Conditions...................................................................................... 19
Routine Maintenance ................................................................................................ 20
Responsibility ........................................................................................................ 20
General.................................................................................................................. 20
RCD Test............................................................................................................... 20
Temperature sensors Calibration .......................................................................... 20
Calibration of the conductivity sensor.................................................................... 21
Accessing the electrical circuits inside the plinth................................................... 22
Contact Details for Further Information ..................................................................... 24
iii
Disclaimer
This document and all the information contained within it is proprietary to Armfield
Limited. This document must not be used for any purpose other than that for which it
is supplied and its contents must not be reproduced, modified, adapted, published,
translated or disclosed to any third party, in whole or in part, without the prior written
permission of Armfield Limited.
Should you have any queries or comments, please contact the Armfield Customer
Support helpdesk (Monday to Thursday: 0830 - 1730 and Friday: 0830 – 1300 UK
time). Contact details are as follows:
United Kingdom
International
(0) 1425 478781
(calls charged at local rate)
+44 (0) 1425 478781
(international rates apply)
Email: support@armfield.co.uk
Fax: +44 (0) 1425 470916
Copyright and Trademarks
Copyright © 2012 Armfield Limited. All rights reserved.
Any technical documentation made available by Armfield Limited is the copyright
work of Armfield Limited and wholly owned by Armfield Limited.
Brands and product names mentioned in this manual may be trademarks or
registered trademarks of their respective companies and are hereby acknowledged.
1
General Overview
The Armfield CEXC Computer Controlled Chemical Reactors Teaching Equipment
demonstrates the characteristics of the important types of chemical reactors.
Continuous stirred tank reactor (CSTR), tubular reactor with plug (PF) and laminar
flow (LF), and stirred tank reactor (batch reactor). Other types of reactor are
demonstrated using separate equipment: CEU, packed bed chemical and enzymic
reactors; and CEP MkII, continuous stirred tank reactors in series.
The reactors available for use with CEXC are as follows:

CEB MkIII Transparent Batch reactor

CEM MkII CSTR

CET MkII Tubular reactor

CEY Plug Flow Reactor

CEZ Laminar Flow Reactor
There is a mounting position on CEXC for three of them, and an independent stand
for the other two. Reactors are interchangeable. CEXC is in effect the bench
providing the services required by each of the reactors such as dual peristaltic pumps
for feed delivery, a hot water circulator or chiller (optional) for constant temperature
operation, and sensors – temperature and conductivity. CEXC is operated with the
built in IFD5 interface to allow computer controlled and data logging. The CEXC with
the CEM MkII is shown below:
CEXC fitted with CEM MkII Continuous Stirred Tank Reactor
2
Equipment Diagrams
Figure 1: CEXC Computer Controlled Service Unit
3
Important Safety Information
Introduction
All practical work areas and laboratories should be covered by local safety
regulations which must be followed at all times.
It is the responsibility of the owner to ensure that all users are made aware of
relevant local regulations, and that the apparatus is operated in accordance with
those regulations. If requested then Armfield can supply a typical set of standard
laboratory safety rules, but these are guidelines only and should be modified as
required. Supervision of users should be provided whenever appropriate.
Your CEX Reactor Bench has been designed to be safe in use when installed,
operated and maintained in accordance with the instructions in this manual. As with
any piece of sophisticated equipment, dangers exist if the equipment is misused,
mishandled or badly maintained.
Water Borne Hazards
The equipment described in this instruction manual involves the use of water, which
under certain conditions can create a health hazard due to infection by harmful
micro-organisms.
For example, the microscopic bacterium called Legionella pneumophila will feed on
any scale, rust, algae or sludge in water and will breed rapidly if the temperature of
water is between 20 and 45°C. Any water containing this bacterium which is sprayed
or splashed creating air-borne droplets can produce a form of pneumonia called
Legionnaires Disease which is potentially fatal.
Legionella is not the only harmful micro-organism which can infect water, but it
serves as a useful example of the need for cleanliness.
Under the COSHH regulations, the following precautions must be observed:

Any water contained within the product must not be allowed to stagnate, ie.
the water must be changed regularly.

Any rust, sludge, scale or algae on which micro-organisms can feed must be
removed regularly, i.e. the equipment must be cleaned regularly.

Where practicable the water should be maintained at a temperature below
20°C. If this is not practicable then the water should be disinfected if it is safe
and appropriate to do so. Note that other hazards may exist in the handling of
biocides used to disinfect the water.

A scheme should be prepared for preventing or controlling the risk
incorporating all of the actions listed above.
Further details on preventing infection are contained in the publication “The Control
of Legionellosis including Legionnaires Disease” - Health and Safety Series booklet
HS (G) 70.
4
Important Safety Information
Electrical Safety
The equipment described in this Instruction Manual operates from a mains voltage
electrical supply. It must be connected to a supply of the same frequency and voltage
as marked on the equipment or the mains lead. If in doubt, consult a qualified
electrician or contact Armfield.
The equipment must not be operated with any of the panels removed.
To give increased operator protection, the unit incorporates a Residual Current
Device (RCD), alternatively called an Earth Leakage Circuit Breaker, as an integral
part of this equipment. If through misuse or accident the equipment becomes
electrically dangerous, the RCD will switch off the electrical supply and reduce the
severity of any electric shock received by an operator to a level which, under normal
circumstances, will not cause injury to that person.
At least once each month, check that the RCD is operating correctly by pressing the
TEST button. The circuit breaker MUST trip when the button is pressed. Failure to
trip means that the operator is not protected and the equipment must be checked and
repaired by a competent electrician before it is used.
Hot Surfaces and Liquids
The unit incorporates a pumped electric water heater, and is capable of producing
temperatures that could cause skin burns.
Before disconnecting any of the pipes or tubing:

Stop all the pumps.

Leave time for the water to cool

Check that the temperature is at a safe level
Do not touch any surfaces close to ‘Hot Surfaces’ warning labels, or any of the
interconnecting tubing, whilst the equipment is in use.
Chemical Safety
Details of the chemicals intended for use with this equipment are given in the
Operational Procedures section. Chemicals purchased by the user are normally
supplied with a COSHH data sheet which provides information on safe handling,
health and safety and other issues. It is important that these guidelines are adhered
to.

It is the user’s responsibility to handle chemicals safely.

Prepare chemicals and operate the equipment in well ventilated areas.

Only use chemicals specified in the equipment manuals and in the
concentrations recommended.

Follow local regulations regarding chemical storage and disposal.
5
Description
Where necessary, refer to the drawings in the Equipment Diagrams section.
Overview
The CEXC Computer Controlled Chemical Reactors Service Unit consists of a
moulded ABS plinth which is used as a mounting for the Chemical reactors to be
used. It also provides the ancillary services for the reactor.
Chemical storage bottles
The reagent bottles consist of two glass bottles which are fitted into the molded
channel. Flexible silicone tubing is used to connect the reagent bottles to the pumps.
Feed pumps
Two variable throughput peristaltic pumps are used to pump the reagents from the
reagent bottles to the fitted reactor. The pumps are mounted on the front of the plinth.
The speed of each pump is individually controlled using the Armfield software via the
USB connector. They can be also calibrated by the user and the data logged for
subsequent calculations.
6
Description
Stirrer
The optional CEM MkII and CEB MkIII reactors are equipped with agitators driven by
an electric motor. The stirrer is also computer controlled using the Armfield software.
The speed can be varied using the up/down arrows or by typing in a value between
0-100%.
Hot water circulator
A clear, acrylic, self-contained hot water circulator is positioned on the plinth at the
front right hand side. (See diagram below).
This vessel incorporates an electrical element for heating water. A thermostat and
level detector are incorporated in the vessel to prevent the heater from operating if
the water is too hot or the level in the vessel is too low. These safety devices are
fixed and cannot be used for experimental purposes.
The lid accommodates an adjustable gland for a variable-height thermocouple sensor
T2 supplied with this unit. The thermocouple is used to measure the fluid temperature
inside the vessel.
Flexible tubes are used to connect the circulator to each reactor. Water, heated by an
electrical heating element in the circulator, is circulated by a gear pump located at the
back of the plinth behind the vessel.
Temperature control of the reactor
Temperature control of the reactor contents is achieved by circulation of heated or
chilled water through a submersed coil or a jacket on the appropriate reactor. The hot
water circulator is integrated with the CEXC service unit. The optional chilled water
circulator (CW-17) is designed to stand on the bench alongside the CEXC and can
be supplied as an accessory if required.
Operation of the heater is controlled by a PID controller in the PC software. The PID
controller maintains the required Hot Water Temperature to obtain a steady Reactor
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Armfield Instruction Manual
Temperature T1. Any offset in the required Reactor temperature T1 on CEB-MKII or
CEM-MKII can be corrected by adjusting the set point of the Hot Water Temperature
T2 in the PID controller. The Set Point temperature, Proportional Band, Integral,
Derivative and Cycle times are all set to default values when the software is loaded
but all of these may be adjusted by the user if required. Default settings for the PID
controller are listed below:
CEB-MKIII
CEM-MKII
CET-MKII
T2
Hot water temperature from circulator
P
10 %
I
100 secs
D
0 secs
Cycle time
10 secs
T2
Hot water temperature from circulator
P
1%
I
0 secs
D
0 secs
Cycle time
10 secs
T1
Reactor temperature (Hot water inside jacket)
P
1%
I
0 secs
D
0 secs
Cycle time
10 secs
PID control of temperature is not required on CEY or CEZ
It is possible to run the reactors at temperatures below ambient by disconnecting the
hot water circulator and connecting the flexible hoses from the chilled water
circulating accessory CW-17 (if supplied). The required chilled water temperature is
set using the thermostat on the chiller unit. Refer to the Instruction Manual supplied
with CW-17 for further details about the chilled water circulator.
Conductivity measurement of the reactor contents
A conductivity probe is supplied to be used individually with any of the reactors. The
conductivity is displayed on the software in units of milliSiemens/cm. During a
chemical reaction, the conductivity of the reacting solution changes as more of the
reactants are converted. This data can be logged and used to determine the degree
of conversion and the rate of conversion.
Reactor attachment
Three of the five chemical reactors are mounted on identical PVC base plates which
are designed to stand on the plinth in the space provided and to be secured to the
base by thumbnuts. CEY and CEZ are supplied with separate stands. Full details for
each of the reactors are given in the appropriate reactor manual.
8
Description
Mains plate at rear of the plinth
In order to use the unit all the circuit breakers and the RCD should be in the ON (up)
position.
9
Installation
Advisory
Before operating the equipment, it must be unpacked, assembled and installed as
described in the steps that follow. Safe use of the equipment depends on following
the correct installation procedure.
Electrical Supply
CEXC-A
Green/yellow lead Earth (Ground)
CEXC-B
CEXC-G
Earth (Ground)
Earth (Ground)
Brown lead
Live (Hot)
Live (Hot)
Live (Hot)
Blue lead
Neutral
Neutral
Neutral
Fuse rating
13A
15A
13A
Voltage
220-240V
110-120V
220V
Frequency
50Hz
60Hz
60Hz
Installing the PC Software
Before operating any of the accessories with the CEXC it will be necessary to install
the software from the CD-ROM supplied with CEXC onto an appropriate PC (PC not
supplied).
For instructions on how to install and run the software insert the CD-ROM into the
optical drive on the PC (PC not supplied) then choose ‘Help’ from the menu.
After installing and running the software for the appropriate accessory on the PC,
instructions on how to operate the software can be obtained by choosing the ‘Help’
tab in the top right hand corner of the screen as shown below:
Note that when operating the software for the first time it will be necessary to enable
the USB virtual COM port by choosing the Red telephone icon (Start COM session).
Full instructions about enabling the port are included in the Help menus.
10
Installation
Installing the Equipment
Mounting the Reactor Unit onto the CEXC

Fit the Reactor Unit (e.g. CEB-MkIII) assembly to the CEXC using the 4
locating studs and black thumbnuts.

Fit the reagent bottles into the moulded channel on the CEXC. Fit tubing on
the left hand side of each of the two feed pumps into the bottles through the
hole in the cap.

Connect the remaining two pipes from the feed pumps to the connectors on
the base or top of the reactor. The feed bottles provided with CEXC are not
required with all reactor units.

Connect the conductivity probe, temperature sensors and the stirrer plugs to
the sockets located on the rear of the CEXC.

Plug the temperature sensor and conductivity sensor supplied with CEXC into
the appropriate sockets at the rear of the service unit then insert the sensors
through the appropriate glands in the lid of the reactor. Check that the
sensors are fully immersed then tighten the glands.

If the reactor has a stirrer connect the stirrer plug to the socket located on the
rear of the CEXC.
Connection to the electrical supply

Check that the voltage specified on the equipment matches the supply
voltage.
NOTE: This unit must be earthed.
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Armfield Instruction Manual

Connect the power socket at the rear of the plinth to a suitable mains
electricity supply.

Ensure that circuit breakers and RCD are ON (up)

The on/off switch for the apparatus is located on the orange panel on the front
of the plinth. Switch on the apparatus
Connection to the Data Logger

Connect CEXC to a PC using the USB cable supplied.

Run the software for the appropriate reactor.
Priming HWC Vessel
12

Turn on the mains switch

Fill HWC vessel with water up to the low level electrode (20 mm from top)

Click Hot Water Circulator button and click Power On. Level of water in the
vessel will decrease as reactor coil is filled. Keep filling the HWC vessel until
the level in the vessel is stable and over the low level electrode.
Installation
Connecting the HWC to Reactor Unit

Connect return pipe of the HWC (1) to the connection for the top of the coil or
tank depending on the reactor unit used.

Connect the supply pipe of the HWC (2) to the connection for the bottom of
the coil or tank depending on the reactor unit used.
Connecting the Reactor Unit to the Chiller

The chiller unit is used when operating temperatures at or below ambient are
required.

The feed and return hoses for the chiller are connected to the jacket of the
reactor through the connections at the top and at the bottom of the reactor
vessel. (See CW-17 manual)

When working with Chiller there is no computer control as PID temperature
controller is needed since CW-17 operates with a Thermostat.

Reactor Unit (e.g. CEB MKIII) software in Isothermal Operation will be used
with ‘Control’ mode OFF. Variables will be monitored but the working
temperature will be established by the thermostat.
Electrical Wiring Diagram
Click on the relevant link to invoke the Wiring Diagram:
Wiring Diagram CDM33265J
Printed Versions of this Instruction Manual
Please note, all wiring diagrams are appended at the rear of this manual. If viewing
this Instruction Manual via Help Text in Armfield Software refer to the printed version
of the manual for these diagrams.
13
Operation
Where necessary, refer to the drawings in the Equipment Diagrams section.
The apparatus must be set up in accordance with the Installation section.
Additionally, ensure you have read the Important Safety Information at the beginning
of this manual.
Operating the PC Software
Each of the accessories associated with CEXC has dedicated PC software that is
installed from the CD-ROM supplied with CEXC.
Details about operating the software can be obtained by choosing the ‘Help’ tab in
the top right hand corner of the screen as shown below:
Operating the Equipment
Switching-on the unit
The unit is switched on using the switch on the front of the unit. The circuit breakers
and RCD device located at the rear of the unit should be turned on beforehand. Both
the temperature controller and conductivity display should illuminate.
Ensure the installation procedure has been followed (Refer to the Installation
Section).
Check the USB connection is made between the CEXC unit and the PC, and, the
CEXC in conjunction with the reactor software, is installed and running on the PC.
Check the circuit breakers and RCD device at the rear left of the unit are in the on
(up) position. Turn the unit on by pressing the ON/OFF switch on the unit. This will
enable the software to display the sensor readings from the service unit.
14
Operation
Operation of Remote Controller/Data Logger and Software
For full details see Operating the Software.
The Armfield CEXC service Unit is controlled using the CEXC software supplied,
which allows real-time monitoring and data logging of all sensor outputs and control
of the peristaltic pumps, hot water circulator and stirrer if reactor requires. Recorded
results can be displayed in tabular and graph format. The software runs on a
WindowsTM PC which connects to the CEXC using a USB interface.
Installation of the software is described in the Installation section, and the software
must be installed before connecting the PC to the CEXC. The software may then be
run from the Start menu (Start > Programs > Armfield Chemical Reactor Software >
CET/CEM/CEB/CEY/CEZ). Operation of the software is described in a walkthrough
presentation within the reactor software, and also in the online Help Text accessible
via the software Help menu. Operation and setting of specific controls is also
provided within the experiments described in this manual.
Mimic Diagram
The equipment is operated and monitored from the Mimic Diagram screen in the
software. This shows all the sensor outputs, and includes controls for the speed of
the pumps, PID temperature controller and the stirrer when reactor requires.
Example of display on CEM MkII software:
15
Armfield Instruction Manual
Controlling the feed pumps
Feed pumps are controlled from the mimic diagram screen in the CEXC software
supplied with each reactor. The pump settings are displayed as flow rate values and
a value in millilitres per minute. The required settings may be typed directly into the
flowrate display box, or adjusted up or down using the arrow keys attached to the
boxes.
Example of display on CEM MkII software:
Operating the stirrer (CEM MkII and CEB MkIII)
Operation is similar to the two feed pumps. Speed is adjusted using the rotary switch
when the selector switch is set to manual.
Operating the heating element
The heater is controlled via the PID control window from the mimic diagram screen of
the reactor chosen in the CEXC software, and the switch is displayed onscreen only
to give an indication. The switch will display a ‘0’ when the heating element is off and
a ‘1’ when the heating element is on.
16
Operation
Priming the vessel
Remove the lid from the hot water vessel. Fill the vessel by pouring clean (preferably
demineralised) water until the level is approximately 20mm from the top.
Check that the low-level indication in the software is not activated.
Setting the hot water temperature
Two modes are available for controlling the hot water temperature, a manual (or
open loop) control mode to provide constant heater power and an auto (or closed
loop) temperature control mode. Both modes are accessed via the software.
To access the heater control mode click the software ‘control’ button close to the
appropriate sensor.
In manual mode, the heater is set to be on for a fixed proportion of time, operator
selectable from 0% to 100%. This mode is useful when assessing energy balances
or settling times.
In auto mode, the power to the heaters is modulated in accordance with a PID
algorithm to achieve a stable temperature at one of the sensors (usually the hot
water inlet to the heat exchanger). Advanced users may change the P, I and D
parameters to perform process control investigations.
17
Armfield Instruction Manual
For experiments with reactor where a constant temperature has to be maintained, the
best mode is the Automatic, and the settings for each reactor are shown in
Operational Procedure in each Manual.
Using the teaching software
If using the CEXC service unit, a USB port at the front of the unit provides a
connection to a compatible PC via connection. By using the appropriate WindowsTM
based Armfield software, any of the sensors outputs provided with the service unit
may then be displayed in real time or logged for display in table or graphical format.
The operation of the WindowsTM based software is described in detail in the Help Text
included with the CEXC software choosing the working reactor. The individual
Teaching Exercises are included with each printed reactor manual, and are also
described in the software Help Text.
18
Equipment Specifications
Overall Dimensions
Height - 0.60m
Width - 1.00m
Depth - 0.50m
Miscellaneous
Peristaltic pump flow rate: 0 - 150 ml/min per pump
Feed bottles capacity: 2.5 L per bottles
Environmental Conditions
This equipment has been designed for operation in the following environmental
conditions. Operation outside of these conditions may result reduced performance,
damage to the equipment or hazard to the operator.
a. Indoor use;
b. Altitude up to 2000m;
c. Temperature 5°C to 40°C;
d. Maximum relative humidity 80% for temperatures up to 31°C, decreasing
linearly to 50% relative humidity at 40°C;
e. Mains supply voltage fluctuations up to ±10% of the nominal voltage;
f.
Transient over-voltages typically present on the MAINS supply;
Note: The normal level of transient over-voltages is impulse withstand (overvoltage) category II of IEC 60364-4-443;
g. Pollution degree 2.
Normally only nonconductive pollution occurs.
Temporary conductivity caused by condensation is to be expected.
Typical of an office or laboratory environment.
19
Routine Maintenance
Responsibility
To preserve the life and efficient operation of the equipment it is important that the
equipment is properly maintained. Regular maintenance of the equipment is the
responsibility of the end user and must be performed by qualified personnel who
understand the operation of the equipment.
General
The equipment should be disconnected from the electrical supply when not in use.
After use the feed tanks, reactor vessel, sump tray and pipework should be washed
through with water to remove chemical residues and then drained.
RCD Test
Test the RCD by pressing the TEST button at least once a month. If the RCD button
does not trip when the Test button is pressed then the equipment must not be used
and should be checked by a competent electrician.
Temperature sensors Calibration
The temperature sensors are calibrated before delivery and should not require recalibration. However, should calibration become necessary follow the below
procedure. This should only be done once the unit has fully warmed up.
Connect CEXC service unit to a PC and start up the Armfield software corresponding
to the reactor in use. Open the corresponding mimic diagram screen where T1, T2
and T3 windows are displayed.
The temperature conditioning circuit (which provides the reading from the
thermocouples supplied with the CEXC service unit) is located on a printed circuit
board inside the plinth on the right-hand side. However, should re-calibration become
necessary the appropriate calibration potentiometers can be located using the
diagram given in Accessing the electrical circuits inside the plinth.
Ensure the equipment has been connected to the electrical supply and switched on
for at least 20 minutes. Start up the Armfield software for the specific reactor. To
access the PCB remove the panel on the right hand side of the plinth by removing
the four fixing screws.
If a thermocouple calibrator is available:
Connect Thermocouple calibrator simulator to T1 input socket, located at the rear of
the plinth. Set to 25ºC and adjust VR1 (T1 ZERO) and VR2 (T1 SPAN) on the PCB to
give 25ºC displayed on PC. Check accuracy at 15º and 40ºC.
Repeat the same procedure for T2 by adjusting VR3 (T2 ZERO) and VR4 (T2 SPAN)
on the PCB to give 25ºC displayed on PC, and VR5 (T3 ZERO) and VR6 (T3 SPAN)
for T3 (if an extra thermocouple is used).
If a thermocouple calibrator is not available:
Temperature sensor T1, T2 and T3 should be dipped into crushed ice, and then
adjust the ZEROS to give 0ºC, then sensors should be dipped into boiling water and
then adjust the SPANS to 100ºC.
20
Routine Maintenance
When the conditioning circuit has been re-calibrated, replace the front panel of the
electrical console and re-install the sensors in the appropriate place on the CEXC
service unit.
Calibration of the conductivity sensor
The conductivity conditioning circuit (which provides the reading from the conductivity
probe supplied with the CEXC service unit) is located on the printed circuit board
shown above inside the electrical console. This circuit is calibrated before despatch
and should not require re-calibration. However, should re-calibration become
necessary the appropriate calibration potentiometers can be located using the
diagram in Accessing the electrical circuits inside the plinth.
Ensure the equipment has been connected to the electrical supply and switched on
for at least 20 minutes. To access the PCB remove the cover plate on the right hand
side of the plinth by unscrewing the four fixing screws. It is not necessary to detach
the PCB from the plinth.
Disconnect the conductivity probe from the socket at the left-hand side of the
electrical console. Connect an AC Voltmeter (Range AC mV) to pins 1 and 2 of the
vacant socket and adjust potentiometer VR10 on the PCB to give a reading of 50 mV
(RMS) on the Voltmeter (probe excitation voltage).
Disconnect the Voltmeter then reconnect the probe to the appropriate socket having
removed the probe from the appropriate reactor fitted to the CEXC.
High conductivity Calibration
Fill a small beaker with a Conductivity standard solution (e.g. 0.1M KCI giving a
conductivity of 12.88 mS at 25°C) and measure the temperature of the standard
solution using a suitable thermometer. From the table supplied determine the actual
conductivity of the solution at the measured temperature.
Immerse the probe into the Conductivity standard solution in the beaker then adjust
potentiometer VR7 to give a reading of the standard solution in the ‘High conductivity’
window on the software to match the conductivity.
Low conductivity Calibration
Fill a small beaker with a Conductivity standard solution (e.g. 0.01M KCI giving a
conductivity of 1.41mS at 25°C) and measure the temperature of the standard
solution using a suitable thermometer. From the table supplied determine the actual
conductivity of the solution at the measured temperature.
Immerse the probe into the Conductivity standard solution in the beaker then adjust
potentiometer VR8 to give a reading of the Standard solution in the ‘Low conductivity’
window on the software.
When the conditioning circuit has been re-calibrated replace the panel and re-install
the probe in the appropriate reactor on the CEXC service unit.
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Armfield Instruction Manual
12.88 mS/cm at 25ºC 0.1 M KCl
1.413 mS/cm at 25ºC 0.01 M KCl
When the conditioning circuit has been re-calibrated replace the front panel of the
electrical console and re-install the probe in the appropriate reactor on the CEX
service unit.
Accessing the electrical circuits inside the plinth
Maintenance of the CEXC service unit does not require access to the electrical
circuits or components located inside the moulded plinth. However, in the event of an
electrical problem, it may be necessary for a competent electrician to gain access to
the inside of the mouldings as follows:
Ensure that the equipment is disconnected from the electrical supply (not just
switched off).
Drain any liquids contained in the reagent vessels or reactors.
Unscrew the channel drain valve located in the recess at the left hand end of the
moulded plinth.
Disconnect the electrical connections between the top and bottom plinth sections by
disconnecting the appropriate connectors.
Unscrew the six fixings around the periphery of the plinth top.
Carefully lift the top moulded section away from the bottom moulded section and
place the top section in a suitable location.
The electrical circuits inside the bottom moulded plinth section are accessible.
22
Routine Maintenance
A circuit diagram showing the mains and DC electrical circuits inside the plinth is
included at the rear of this manual to assist in fault finding.
Should it be necessary to remove the cover plate at the right hand side of the plinth
by unscrewing the four fixings then the PCB connections diagram below shows the
location and function of the electrical connectors on the PCB to aid re-assembly.
Re-assembly of the top and bottom moulded plinth sections is the inverse of the
above instructions.
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Contact Details for Further Information
Main Office:
Armfield Limited
Bridge House
West Street
Ringwood
Hampshire
England BH24 1DY
Tel: +44 (0)1425 478781
Fax: +44 (0)1425 470916
Email: sales@armfield.co.uk
Web: http://www.armfield.co.uk
US Office:
Armfield Inc.
9 Trenton - Lakewood Road
Clarksburg, NJ 08510
Tel/Fax: (609) 208 2800
Email: info@armfieldinc.com
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