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Engineering Teaching& Research Equipment

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uid Mechanics, Fluid Machines, Hydraulics & Hydrology, Water Treatment, Irrigation Water Management, Heat Transfer, Thermodynamics

, Refrigeration & Air Conditioning,

CONTINUOUS STIRRED TANK REACTOR

Instruction ManualCEM-Mkll

ISSUE 17

December 201

ii

Table of ContentsCopyright and Trademarks 1

Use with CEX Service Unit. 2

General Overview 3

Equipment Diagrams 4

Important Safety Information 5

Introduction 5

Water Borne Hazards 5

Electrical Safety ~ 5

Hot Surfaces and Liquids 6

Chemical Safety 6

Description 7

Overview 7

Flow of materials 7

Installation 9

Advisory 9

Installation Process 9

Operation 12

Operating the Software 12

Operating the Equipment. 22

Equipment Specifications 28

Overall Dimensions 28

Environmental Conditions 28

Routine Maintenance 29

Responsibility 29

General 29

RCD Test. 29

Temperature sensors calibration 29

Calibration of the conductivity sensor 29

Laboratory Teaching Exercises 32

Table of Contents

Index to Exercises 32

Nomenclature 32

Common Theory 33

Exercise A - To find the reaction rate constant in a Continuous Stirred Tank Reactor.................................................................................................................................. 36

Exercise B - To determine the effect of inadequate mixing on the reaction rate 41

Exercise C - Determination of the Residence Time using tracer techniques 42

Contact Details for Further Information l. 45

iii

(O) 1425478781(calls charged at local rate)

+44 (O) 1425478781(international rates apply)

DisclaimerThis document and all the information contained within it is proprietary to ArmfieldLimited. This document must not be used for any purpose other than that for which itis 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 writtenpermission of Armfield Limited.

Should you have any queries or comments, please contact the Armfield CustomerSupport helpdesk (Monday to Friday: 0800 - 1800 GMT). Contact details are asfollows:

Email: [email protected]

Fax: +44 (O) 1425470916

Copyright and TrademarksCopyright © 2009 Armfield Limited. AII rights reserved.

Any technical documentation made available by Armfield Limited is the copyrightwork of Armfield Limited and wholly owned by Armfield Limited.

Brands and product names mentioned in this manual may be trademarks orregistered trademarks of their respective companies and are hereby acknowledged.

1

2

Use with CEX Service UnitThis instruction manual describes the use of the CEM-MKII Reactor in conjunctionwith the CEXC Computer Controlled Service Unit.

An alternative instruction manual is available from Armfield that describes the use ofthe CEM-MKII in conjunction with the CEX Service Unit. Please contact Armfield if acopy of this instruction manual is required. Contact details are included later in thisdocument.

3

General OverviewTHIS INSTRUCTION MANUAL SHOULD BE USED IN CONJUNCTION WITH THEMANUAL SUPPLlED WITH THE CEXC COMPUTER CONTROLLED CHEMICALREACTOR SERVICE UNIT.

This Manual provides the necessary information for operating the equipment inconjunction with the CEXC Computer Controlled Chemical Reactor Service Unit, andfor performing a range of Teaching Exercises designed to demonstrate the basicprincipies of Chemical Reactors theory and use.

The continuous stirred tank reactor in the form of either a single tank or (more often)tanks in series, is used widely and is particularly suitable for liquid phase reactions. Itis particularly used in the organic chemicals industry. Advantages include consistentproduct quality, straightforward automatic control and low manpower requirements.

The Armfield CEM Mkll Tubular Flow Reactor is specially designed to allow detailedstudy of this important process. It is one of five reactor types which areinterchangeable on the Reactor Service Unit (CEXC), the others being CET Mkll -Tubular Reactor, CEB Mklll - Transparent Batch Reactor, CEY Plug flow reactor andCEZ Laminar Flow reactor.

Reactions are monitored by conductivity probe as the conductivity of the solutionchanges with conversion of the reactants to product and by temperature.

CEXC fitted with CEM Mkll Continuous Stirred Tank Reactor

4

Equipment Diagrams

Reagent feed connection

Stirrer motor Conductivity sensor

Agitator JL._- Gland

___-li--- GlandBaffle

Standpipe

Motor electrical plug

Hexagon backing nut

Reagent feed connection Drain valve

,.-'i....j¡.<~'--_/-_..l-..L- __ .,¡L~~~. Thumb nut

Support column

Figure 1: Reactor Unit

• Any water contained within the product must not be allowed to stagnate, ie.the water must be changed regularly.

Important Safety Information

Introd uctionAII practical work areas and laboratories should be covered by local safetyregulations which must be followed at all times.

It is the responsibility of the owner to ensure that all users are made aware ofrelevant local regulations, and that the apparatus is operated in accordance withthose regulations. If requested then Armfield can supply a typical set of standardlaboratory safety rules, but these are guidelines only and should be modified asrequired. Supervision of users should be provided whenever appropriate.

Your CEM-Mkll Continuous Stirred Tank Reactor has been designed to be safe inuse when installed, operated and maintained in accordance with the instructions inthis manual. As with any piece of sophisticated equipment, dangers exist if theequipment is misused, mishandled or badly maintained.

Water Borne HazardsThe equipment described in this instruction manual involves the use of water, whichunder certain conditions can create a health hazard due to infection by harmfulmicro-organisms.

For example, the microscopic bacterium called Legionella pneumophila will feed onany sea le, rust, algae or sludge in water and will breed rapidly if the temperature ofwater is between 20 and 45°C. Any water containing this bacterium which is sprayedor splashed creating air-borne droplets can produce a form of pneumonia calledLegionnaires Disease which is potentially fatal.

Legionella is not the only harmful micro-organism which can infect water, but itserves as a useful example of the need for cleanliness.

Under the COSHH regulations, the following precautions must be observed:

• Where practicable the water should be maintained at a temperature below20°C. If this is not practicable then the water should be disinfected if it is safeand appropriate to do so. Note that other hazards may exist in the handling ofbiocides used to disinfect the water.

• Any rust, sludge, scale or algae on which micro-organisms can feed must beremoved regularly, i.e. the equipment must be cleaned regularly.

• A scheme should be prepared for preventing or controlling the riskincorporating all of the actions listed above.

Further details on preventing infection are contained in the publication "The Controlof Legionellosis including Legionnaires Disease" - Health and Safety Series bookletHS (G) 70.

Electrical SafetyThe equipment described in this Instruction Manual operates from a mains voltageelectrical supply. It must be connected to a supply of the same frequency and voltage

5

r

- Stop all the pumps.

Armfield Instruction Manual

as marked on the equipment or the mains lead. If in doubt, consult a qualifiedelectrician 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 CurrentDevice (RCD), alternatively called an Earth Leakage Circuit Breaker, as an integralpart of this equipment. If through misuse or accident the equipment becomeselectrically dangerous, the RCD will switch off the electrical supply and reduce theseverity of any electric shock received by an operator to a level which, under normalcircumstances, will not cause injury to that persono

At least once each month, check that the RCD is operating correctly by pressing theTEST button. The circuit breaker MUST trip when the button is pressed. Failure totrip means that the operator is not protected and the equipment must be checked andrepaired by a competent electrician before it is used.

Hot Surfaces and LiquidsThe unit incorporates a pumped electric water heater, and is capable of producingtemperatures that could cause skin burns.

Before disconnecting any of the pipes or tubing:

- 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 theinterconnecting tubing, whilst the equipment is in use.

Chemical SafetyDetails of the chemicals intended for use with this equipment are given in theOperational Procedures section. Chemicals purchased by the user are normallysupplied with a COSHH data sheet which provides information on safe handling,health and safety and other issues. It is important that these guidelines are adheredto.

• 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 theconcentrations recommended.

• Follow local regulations regarding chemical storage and disposal.

6

7

DescriptionWhere necessary, refer to the drawings in the Eguipment Diagrams section.

OverviewThe reactor vessel is set on a baseplate which is designed to be located on the fourstuds of the CEXC service unit and then secured by thumbnuts. The reactor issupported by three pillars; position the reactor on the CEXC service unit such that asingle pillar is to the front.

A stainless steel coil inside the reactor provides the heat transfer surface for eitherheating or coiling the chemical reactants. The coil is connected either to the hot watercirculator or the CW-17 chiller. The coil inlet is at the front of the reactor and the coilreturn is at the rear of the reactor.

A turbine agitator works in conjunction with a baffle arrangement to provide efficientmixing and heat transfer. The agitator is driven by an electric motor mounted in thelid of the reactor. The motor is controlled by the software supplied with the ServiceUnit. The socket for the motor electrical plug is sited at the rear of the service unit.

Glands in the reactor lid house the conductivity and temperature sensors providedwith the service unit. The larger of the two glands is for the conductivity probe. Theglands are unscrewed by hand, the probes inserted completely into the reactor untilthey rest on the reactor base and then the glands re-tightened by hand. Sockets atthe rear of the service unit are provided to connect each probe. These are of differentsize so that the probes cannot be wrongly connected.

Flow of materialsChemical reagents are pumped from the two feed bottles into the reactor separatelythrough connectors in the base of the reactor. The two feed pumps of the service unitare connected to these. As reagents are pumped into the reactor, the level increasesuntil it finally overflows the stand pipe and flows to drain. The stand pipe may beadjusted in height by loosening the hexagonal backing nut. A mark is etched onto thestand pipe. For maximum operating volume of the reactor, this mark should bealigned with the backing nut. A stop prevents the stand pipe from being completelyremoved, and this also defines the minimum working volume which is half themaximum volume.

When the reactor is not being used, it can be drained using the valve sited on theunderside of the reactor.

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CEM MKII CONTINUOUS STlRRED TANK REACTOR

Installation

AdvisoryBefore operating the equipment, it must be unpacked, assembled and installed asdescribed in the steps that follow. Safe use of the equipment depends on followingthe correct installation procedure.

Installation Process1. MOUNTING THE CEM MKII ONTO THE CEXC

• Connect the remaining two pipes from the feed pumps to the connectors onthe base of the reactor as shown.

• Fit the CEM-MKII assembly to the CEXC using the 4 locating studs and blackthumbnuts. The reactor is supported by 3 pillars; position the reactor on theCEXC so that a single pillar support is foremost.

• Connect the conductivity probe, temperature sensors and the stirrer plugs tothe sockets located on the rear of the CEXC.

• Fit the conductivity and temperature sensors to the CEM. Each probe fits in agland. The gland nut should be loosened to fit the probes and then tightenedto secure them. Probes should reach the bottom of the reactor.

CEXC fitted with CEM Mkll Continuous Stirred Tank Reactor

2. CONNECTION TO HOT WATER CIRCULATOR

• Connect suction pipe of the HWC (1) to the connection for the top of the coil(rear).

• Connect the supply pipe of the HWC (2) to the connection for the bottorn ofthe coil (front)

9

~----------------------


3. CONNECTION TO ElECTRICITY SUPPl y

• Check the voltage specified on the equipment matches the supply voltaqe.

NOTE: this unit must be earthed.

• Connect the power socket at the rear of the plinth to a suitable mainselectricity supply.

• Ensure the circuit breakers and RCD are switched to ON (up position).

• The on/off switch for the apparatus is located on the orange panel on the frontof the plinth. Switch on the apparatus.

4. CONNECTION TO THE DATA lOGGER

• Connect CEXC to a PC using the USB cable supplied.

• Insert the CEM Mkll software CD-ROM into the CD-R drive of a suitable PC.The installation program should auto run. If it does not, select 'Run ...' fromyour Start menu, type run d:\setup where d is the letter of your CD-ROMdrive.

• Follow the instructions on screen

• Run the software

5. FllLlNG HWC VESSEl AND REACTOR COll

• Turn on the mains switch

• Fill HWC vessel with water up to the low level tip (30 cm from top)

10

Installation

..IJptional Ternp. T2 ¡

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,

Heeter

Hol W.~ter Circulator,• 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 untilthe level is stable and over the Low level tipo

11

OperationWhere necessary, refer to the drawings in the Equipment Diagrams section.

The apparatus must be set up in accordance with the Installation section.Additionally, ensure that you have read the Important Safety Information at thebeginning of this manual.

Operating the SoftwareNote: The diagrams in this section are included as typical examples and may notrelate specifically to the individual product described in this instruction manual.

The Armfield Software is a powerful Educational and Data Logging tool with a widerange of features. Some of the major features are highlighted below, to assist users,but full details on the software and how to use it are provided in the presentations.and Help text incorporated in the Software. Help on Using the Software or Using theEquipment is available by clicking the appropriate topic in the Help drop-down menufrom the upper toolbar when operating the software as shown:

l~ Tñ~5t;¡fuW!¡e tüsing Th9fi:¡ulprn9.nr • ;-.,....;.~.;.;:;.....~-~~---...-,;

Before operating the software ensure that the equipment has been connected to theIFD5 Interface (where IFD5 is separate from the equipment) and the IFD5 has beenconnected to a suitable pe using a USB lead. For further information on theseactions refer to the Operation manual.

Load the software. If multiple experiments are available then a menu will bedisplayed listing the options. Wait for the presentation screen to open fully as shown:

Before proceeding to operate the software ensure that IFD: OK is displayed at thebottom of the screen. If IFD:ERROR is displayed check the USB connection between

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th"",······· ••····.··p·····.·~t'~"······S'1: .ese ,rWliPu:"oLlan

ThesepTasentatioos are <.1e5ígnoo .'.o ali(.hf¡l yoo toquki\l)' u~ardoowto:

• UooihlS sofi:v·~'.afe." Use thEt ¡¡¡quipment" Carry 01.11100 ralo '119 e:<en::isBR

Use lhe bUltms al U1etdtom rl too SQ'00fl ana t19~1I al the lefttonavlg¡ftí thrOOghtte presentations

12

Operation

the IFD5 and the PC and confirm that the red and green LED's are both illuminated.If the problem persists then check that the driver is installed correctly (refer to theOperation manual).

Presentation Screen . Basics and NavigationAs stated above, the software starts with the Presentation Screen displayed. Theuser is met by a simple presentation which gives them an overview of the capabilitiesof the equipment and software and explains in simple terms how to navigate aroundthe software and summarizes the major facilities complete with direct links to detailedcontext sensitive 'help' texts.

To view the presentations click Next or click the required topic in the left hand paneas appropriate. Click More while displaying any of the topics to display a Help indexrelated to that topic.

To return to the Presentation screen at any time click the View Presentation icon

>" from the main tool bar or click Presentation from the dropdown menu asshown:

- c"-' ro~lb.r;Ccri~t\!t·ts-·-

For more detailed information about the presentations refer to the Help available viathe upper toolbar when operating the software.

ToolbarA toolbar is displayed at the top of the screen at all times, so users can jumpimmediately to the facility they require, as shown:

The upper menu expands as a dropdown menu when the cursor is placed over aname.

The lower row of icons (standard for all Armfield Software) allows a particularfunction to be selected. To aid recognition, pop-up text names appear when thecursor is placed over the icono

Mimic DiagramThe Mimic Diagram is the most commonly used screen and gives a pictorialrepresentation of the equipment, with continuously updated display boxes for all thevarious sensor readings, calculated variables etc. directly in engineering units.

13


To view the Mimic Diagram click the View Diagram icon from the main tool baror click Diagram from the View drop-down menu as shown:

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A Mimic diagram is displayed, similar to the diagram as shown:

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The details in the diagram will vary depending on the equipment chosen if multipleexperiments are available.

In addition to measured variables such as Temperature, Pressure and Flowrate (froma direct reading flowmeter), calculated data such as Motor Torque, Motor Speed andDischarge / Volume flowrate (from pressure drop across an orifice plate) arecontinuously displayed in data boxes with a white background. These areautomatically updated and cannot be changed by the user.

Manual data input boxes with a coloured background allow constants such as OrificeCd and Atmospheric Pressure to be changed by over-typing the default value, ifrequired.

The data boxes associated with some pressure sensors include a Zero buttonalonqside. This button is used to compensate for any drift in the zero value, which isan inherent characteristic of pressure sensors. Pressing the Zero button just before

14

Operation

starting a set of readings resets the zero measurement and allows accurate pressuremeasurements to be taken referenced to atmospheric pressure. This action must becarried out before the motor is switched on otherwise the pressure readings will beoffset.

The mimic diagram associated with some products includes the facility to selectdifferent experiments or different accessories, usually on the left hand side of thescreen, as shown:

¡Samplet·.1ode -Menuel

Clicking on the appropriate accessory or exercise will change the associated mimicdiagram, table, graphs etc to suit the exercise being performed.

Control Facilities in the Mimic DiagramA Power On button allows the motor to be switched off or on as required. The buttonalways defaults to off at startup. Clicking this button switches the power on (1) and off(O) alternately.

A box marked Motor Setting allows the speed of the motor to be varied from O to100% either stepwise, by typing in values, or using the up / down arrows asappropriate. It is usual to operate the equipment with the motor initially set to 100%,then reduce the setting as required to investigate the effect of reduced speed onperformance of the equipment.

When the software and hardware are functioning correctly together, the green LEOmarked Watchdog Enabled will alternate On and Off. If the Watchdog stopsalternating then this indicates a loss of communication between the hardware andsoftware that must be investigated.

Oetails on the operation of any automatic PIO Controlloops in the software areincluded later in this section.

Data Logging Facilities in the Mimic DiagramThere are two types of sampling available in the software, namely Automatic orManual. In Automatic logging, samples are taken regularly at a preset but variable

15


interval. In Manuallogging, a single set of samples is taken only when requested bythe operator (useful when conditions have to be changed and the equipment allowedto stabilize at a new condition before taking a set of readings).

The type of logging will default to manual or automatic logging as appropriate to thetype of product being operated.

Manual logging is selected when obtaining performance data from a machine whereconditions need to stabilize after changing appropriate settings. To record a set of set

of data values from each of the measurement sensors click the icon from the

main toolbar. One set of data will be recorded each time the icon is clicked.

Automatic logging is selected when transients need to be recorded so that they can

be plotted against time. Click the icon from the toolbar to start recording, click

the • icon from the toolbar to stop recording.

The type of logging can be configured by clicking Configure in the Sample drop-down menu from the upper toolbar as shown:

In addition to the choice of Manual or Automatic sampling, the parameters forAutomatic sampling can also be set. Namely, the time interval between samples canbe set to the required number of minutes or seconds. Continuous sampling can beselected, with no time limit or sampling for a fixed duration can be set to the requirednumber of hours, minutes or seconds as shown:

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Tabular Display

To view the Table screen click the View Table icon E from the main tool bar orclick Table from the View dropdown menu as shown:

16

17

Operation

The data is displayed in a tabular format, similar to the screen as shown:

As the data is sampled, it is sto red in spreadsheet format, updated each time thedata is sampled. The table also contains columns for the calculated values.

New sheets can be added to the spreadsheet for different data runs by clicking the

icon from the main toolbar. Sheets can be renamed by double clicking on thesheet name at the bottom left corner of the screen (initially Run 1, Run 2 etc) thenentering the required name.

For more detailed information about Data Logging and changing the settings withinthe software refer to the Help available via the upper toolbar when operating thesoftware.

Graphical DisplayWhen several samples have been recorded, they can be viewed in graphical format.

-------------------------_ .._----_ .._-


To view the data in Graphical format click the View graph icon from the maintool bar or click Graph from the View drop-down menu as shown:

The results are displayed in a graphical format as shown:

(The actual graph displayed will depend on the product selected and the exercisethat is being conducted, the data that has been logged and the parameter(s) that hasbeen selected).

Powerful and flexible graph plotting tools are available in the software, allowing theuser full choice over what is displayed, including dual y axes, points or lines,displaying data from different runs, etc. Formatting and scaling is done automaticallyby default, but can be changed manually if required.

To change the data displayed on the Graph click Graph Data from the Formatdropdown menu as shown:

18

Operation

The available parameters (Series of data) are displayed in the left hand pane asshown:

Two axes are available for plotting, allowing series with different scaling to bepresented on the same x axis.

To select a series for plotting, click the appropriate series in the left pane so that it ishighlighted then click the appropriate right-facing arrow to move the series into one ofthe windows in the right hand pane. Multiple series with the same scaling can beplotted simultaneously by moving themall into the same window in the right pane.

To remove a series from the graph, click the appropriate series in the right pane sothat it is highlighted then click the appropriate left-facing arrow to move the series intothe left pane.

The X-Axis Content is chosen by default to suit the exercise. The content can bechanged if appropriate by opening the drop down menu at the top of the window.

The format of the graphs, scaling of the axes etc. can be changed if required byclicking Graph in the Format drop-down menu as shown:

19


For more detailed information about changing these settings refer to the Helpavailable via the upper toolbar when operating the software.

PIO ControlWhere appropriate, the software associated with some products will include a singleor multiple PIO controlloops whereby a function on the product can be manually orautomatically controlled using the PC by measuring an appropriate variable andvarying a function such as a heater power or pump speed.

The PIO loop can be accessed by clicking the box labelled PID or Control dependingon the particular software:

APIO screen is then displayed as shown:

20

Operation

The Mode of operation always defaults to Manual control and 0% output when thesoftware is loaded to ensure safe operation of the equipment. If appropriate, theoperator can retain manual operation and simply vary the value from Oto 100% in theManual Output box, then clicking Apply.

Alternatively, the PIO loop can be changed to Automatic operation by clicking theAutomatic button. If any of the PIO settings need to be changed from the defaultvalues then these should be adjusted individually before clicking the Apply button.

The controller can be resto red to manual operation at any time by clicking theManual button. The value in the Manual Output box can be changed as requiredbefore clicking the Apply button.

Settings associated with Automatic Operation such as the Setpoint, ProportionalBand, Integral Time, Derivative Time and Cycle Time (if appropriate) can bechanged by the operator as required before clicking the Apply button.

Clicking Calculations displays the calculations associated with the PIO loop to aidunderstanding and optimization of the loop when changing settings as shown:

21


Clicking Settings returns the screen to the PIO settings.

Clicking OK closes the PIO screen but leaves the loop running in the background.

In some instances the Process Variable, Control variable and Control Action canbe varied to suit different exercises, however, in most instances these boxes arelocked to suit a particular exercise. Where the variables can be changed the optionsavailable can be selected via a drop-down menu.

Advanced Features

The software incorporates advanced features such as the facility to recalibrate thesensor inputs from within the software without resorting to electrical adjustments ofthe hardware. For more detailed information about these advanced functions withinthe software refer to the Help available via the upper toolbar when operating thesoftware.

Operating the Equipment

Switching on the unit

The unit is switched on using the switch on the front of the unit. The circuit breakersand RCO device located at the rear of the unit should be turned on beforehand. Boththe temperature controller and conductivity display should illuminate.

22

Operation

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===========--- I ¿nJoff switch

Filling the feed bottlesLift the feed bottle lids and pour solutions in from above.

Operation Hot Water CirculatorThe hot water circulator vessel should be filled with water before use, and drainedafter use if the equipment is not going to be used for some time. When in use fill thevessel by pouring clean (preferably demineralised) water until the level isapproximately 30 mm from the topo

Top up the level of this vessel as necessary to maintain the level above the tip of thelevel electrode (typically 30 mm from the top of the vessel).

Heater is controlled from a PC via the CEM software. APIO controller within thesoftware maintains the heater setting based on the temperature measured by thechosen temperature sensor. The Set Point temperature, proportional Band and theIntegral and Oerivative times may be adjusted by the user. Alternatively the heaterpower setting may be entered manually as a percentage value, using the samecontroller window as for the PIO settings.

See below PIO settings for the HWC.

Operation of Data Logger and SoftwareThe Tubular Reactor is controlled using the CEM Mkll software supplied, whichallows real-time monitoring and data logging of all sensor outputs and control of theheater unit and pumps. Recorded results can be displayed in tabular and graphformat. The software runs on a Windows ™ PC which connects to the CEXC using aUSB interface.

Installation of the software is described in the Installation Guide, and the softwaremust be installed before connecting the PC to the CEXC. The software may then be

23

24


run from the Start menu (Start > Programs > Armfield Chemical Reactor Software>CEM).

Operation of the software is described in a walkthrough presentation within thesoftware, and also in the online Help Text accessible via the software Help menu.Operation and setting of specific controls is also provided within the experimentsdescribed in this manual.

Mimic Diagram and softwareThe equipment is usually controlled from the Mimic Diagram screen in the software.This shows all the sensor outputs, and includes controls for the pumps and the Hotwater Circulator. There is an extra temperature 'T3' and 'Low conductivity' plug withoutputs on the software for extra connections made by the user.

Feed pump speeds are controlled using up/down arrows or typing the flow rate in avalue between O and the maximum ml/min. Click on the appropriate POWER ONsymbol to start up the pumps.

Concentration values must be typed in on each experiment so that software will carryout the subsequent calculations.

Conductivity and temperature values will be monitored on the screen and datalogged when 'GO' is clicked.

CEM Continuous Stirred Tank Reactor can be used with heater or with Chiller. Whenthe Heater is used settings on the software are required. When using the Chiller CW-17 PID settings are not required. See the Installation section for appropriatecontroller settings when using the CW-17.

The software also automatically generates a series of 'Watchdog' pulses, required bythe pie, ensuring that the hardware shuts down safely in case of a software orcommunications failure.

25

Operation

Controlling the Hot Water Circulator (HWC)The heater is controlled by a controller in the software. Click on the appropriateCONTROL symbol to open the controller window.

Próporfional Band

Int(lgrEiI Time

SP = Chosen by the user IT = O Cycle time = 1


Control can be either closed loop (Automatic) which uses the temperature sensorimmediately following the heater as the process variable in a PIO loop, or open loop(Manual) where the user defines the percentage time the heaters are 'ON' for, andhence the output power.

When performing a reaction it is best to use Automatic control as this producesstable temperatures most rapidly, and maintains these conditions by varying theheater power.

Choose Reactor Temperature as PROCESS VARIABLE to control, set the PIO loopas convenient and click 'Hot Water Circulator' symbol. Then click 'Power en' andwater will start to recirculate.

PIO Settings for Experiment with Heater:

Process variable = Reactor Temperature (T1)

Control Variable = Heater

Control Action = Reverse

PB = 50 OT = O

Operating the CEM MkllTemperature in the reactor is monitored on the software and is controlled bycirculating heating or cooling liquid through the internal coil.

There are two modes of operation with the CEM: Experiment with HEATER and withCHILLER.

When using the Chiller CW-17 PIO settings are not required. See the Installationsection for appropriate controller settings when using the CW-17.

When using the Heater the temperature sensor T1 supplied with CEXC, which isReactor Temperature on the software, should be set as the Process Variable to becontrolled in the PIO loop. This sensor must be immersed in the reactor vessel andwill be data logged.

The volumetric ratio in which the reactants are mixed is defined by the relative flowrates of the two pumps. If the pumps are operated at the same flow rate then thereactants are mixed in equal volumes.

The degree of mixing may be adjusted using the agitator speed control box on themain screen of the software.

The extent of conversion of the reactants is determined from the conductivity, whichis measured by the conductivity probe.

26

_. _._-~--~~~~~~~~~--------~

Operation

27

28

11

Equipment Specifications

Overall Dimensions

Reactor dimensions:

Vessel diameter: 0.153m

Maximum vessel depth: 0.108m

Maximum volume: 2.0L

Minimum vessel depth: 0.054m

Minimum operating volume: 1.0L

Environmental ConditionsThis equipment has been designed for operation in the following environmentalconditions. 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 2000 m;

c. Temperature 5 °C to 40°C;

d. Maximum relative humidity 80 % for temperatures up to 31°C, decreasinglinearly 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 normallevel of transient over-voltages is impulse withstand (over-voltage) category 11 of lEC 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

29

Routine Maintenance

ResponsibilityTo preserve the life and efficient operation of the equipment it is important that theequipment is properly maintained. Regular maintenance of the equipment is theresponsibility of the end user and must be performed by qualified personnel whounderstand the operation of the equipment.

GeneralThe equipment should be disconnected from the electrical supply when not in use.After use the feed bottles, reactor vessel, sump tray and pipework should be washedthrough with water to remove chemical residues and then drained.

RCD TestTest the RCD by pressing the TEST button at least once a month. If the RCD buttondoes not trip when the Test button is pressed then the equipment must not be usedand should be checked by a competent electrician.

Temperature sensors calibrationThe temperature sensors are calibrated before delivery and should not require re-calibration. However should calibration become necessary follow the belowprocedure. This should only be done once the unit has fully warmed up.

The temperature conditioning circuit (which provides the reading from theconductivity probe supplied with the CEXC service unit) is located on a printed circuitboard inside the plinth on the right-hand side. This circuit is calibrated beforedespatch and should not require re-calibration. However, should re-calibrationbecome necessary the appropriate calibration potentiometers can be located usingthe diagram given in the CEXC manual (Routine Maintenance).

Connect CEXC service unit to a PC and start up the Armfield software. Open mimicdiagram screen where T1, T2 and T3 windows are displayed.

If a thermocouple calibrator is available:

Connect Thermocouple calibrator simulator to T1 input socket. Set to 25°C andadjust VR1 (T1 ZERO) and VR2 (T1 SPAN) on the PCB to give 25°C displayed onPC. Check accuracy at 15° and 40°C.

Repeat the same procedure for T2 by adjusting VR3 (T2 ZERO) and VR4 (T2 SPAN)on the PCB to give 25°C displayed on PC, and VR5 (T3 ZERO) and VR6 (T3 SPAN)tor T3.

If a thermocouple calibrator is not available:

Temperature sensor T1, T2 and T3 should be dipped into crushed ice, and thenadjust the ZEROS to give O°C, then sensors should be dipped into boiling water andthen adjust the SPANS to 100°C.

Calibration of the conductivity sensorThe conductivity conditioning circuit (which provides the reading from the conductivityprobe supplied with the CEXC service unit) is located on the printed circuit boardshown above inside plinth. This circuit is calibrated before despatch and should not


require re-calibration. However, should re-calibration become necessary theappropriate calibration potentiometers can be located using the diagram above.

Ensure the equipment has been connected to the electrical supply and switched onfor at least 20 minutes. To access the PCB remove the cover plate on the right handside of the plinth by unscrewing the four fixing screws. It is not necessary to detachthe PCB from the plinth.

Disconnect the conductivity probe from the socket at the at the rear of the unit.Connect an AC Voltmeter (Range AC mV) to pins 1 and 2 of the vacant socket andadjust potentiometer VR1 Oon the PCB to give a reading of 50 mV (RMS) on theVoltmeter (probe excitation voltage).

Disconnect the Voltmeter then reconnect the probe to the appropriate socket havingremoved the probe from the appropriate reactor fitted to the CEXC.

High conductivity Calibration

Fill a small beaker with a Conductivity standard solution (e.g. 0.1 M KCI giving aconductivity of 12.88 mS at 25°C) and measure the temperature of the standardsolution using a suitable thermometer. From the table supplied determine the actualconductivity of the solution at the measured temperature.

Immerse the probe into the Conductivity standard solution in the beaker then adjustpotentiometer 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. 0.01 M KCI giving aconductivity of 1.41 mS at 25°C) and measure the temperature of the standardsolution using a suitable thermometer. From the table supplied determine the actualconductivity of the solution at the measured temperature.

Immerse the probe into the Conductivity standard solution in the beaker then adjustpotentiometer 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-installthe probe in the appropriate reactor on the CEXC service unit.

12.88 mS/cm at 25°C 0.1 M KCI

°C mS/cm °C mS/cm

5 8.22 20 11.67

10 9.33 21 11.91

15 10.48 22 12.15

16 10.72 23 12.39

17 10.95 24 12.64

30

1_::------+¡:-:-:-:---------1If-::------I-: :_8_1 :-----

Routine Maintenance

1.413 mS/cm at 25°C 0.01 M KCI

°C mS/cm DC mS/cm

5 0.896 20 1.278

10 1.02 21 1.305

15 1.147 - 22 1.332

16 1.173 23 1.359

17 1.199 24 1.386

18 1.225 25 1.413

19 1.251 26 1.441

31

Laboratory Teaching Exercises

Index to ExercisesExercise A - To find the reaction rate constant in a Continuous Stirred Tank Reactor

Exercise B - To determine the effect of inadeguate mixing on the reaction rate

Exercise C - Determination of the Residence Time using tracer technigues

Nomenclature

sodium hydroxide conc. in mi

(same subscripts as above for a)

sodium hydroxide conc. in reactor attime t

sodium hydroxide conc. in reactor afterOJ time

ethyl acetate conc.

um acetate conc.e

me subscripts as above for a)

F total volume feed rate

Fa volumetric feed rate of sodium hydroxide

k specific rate constant

r reaction rate

tR residence time (s)

e (s)

T perature (K)

v volume of reactor

conversion of sodium hydroxide =

32


33

~-~~------ao - al

ao

conversion to sodium acetate =Xc cl -co

e'D

,:Jl

., " .v_

conductivity (Siemens/cm)¡

i~itial conductivity-~'-

Jloii Jll conductivity at time t¡

j/10 conductivity after 00 time,

; Jla sodium hydroxide conductivity,

Jlc sodium acetate conductivitys

C concentration in reactor at time t afterinput step change I

I¡Ca concentration of the input

-~-~~-~-~-~ , --------time constant

Cornrnon TheoryThe Armfield continuous stirred tank reactor is designed to demonstrate themechanism of a chemical reaction in this type of reactor as well as the effects ofvarying the process conditions such as reaction temperature, reactor volume, stirringrate, feed rate etc.

The reactor volume can be varied by adjusting the height of the internal standpipe.The actual volume must be checked by filling the reactor with water to the overflowthen draining the reactor contents into a measuring cylinder.

The conductivity of the reacting solution in the reactor changes with the degree ofconversion and this provides a convenient method for monitoring the progress of thereaction either manually or by computer.

The reaction chosen is the saponification of ethyl acetate by sodium hydroxide as itcan be carried out under safe conditions of temperature and preSS¡éand is welldocumented. ( ,

The experiments involve the collection and storage of conductivit>\ data. The USBport located at the front of the Service Unit must be connected to t,\e computer. Thiswill enable data logging of the conductivity and temperature sensor a~elected timeintervals over a selected period of time. ~

~


Although it may be possible to carry out demonstrations using other chemicals, it isnot advisable as the materials of construction of the reactor may not be compatible.

Before carrying out reactions involving any other reagents please refer to ArmfieldUd. for advice.

Dilution of Ethyl Acetate

Armfield recommends the use of a 0.1 M solution of Ethyl Acetate in the CEM Mkllreactor. This should be made by diluting concentrated Ethyl Acetate as follows:

Mol \Vt 1 88.11 979 _1 ti .Volume ofconcentrate = x---= =. rru per tre of solution10 Density 10xO.90

Therefore add 9.79 mi of concentrated Ethyl Acetate to 900 rnl-of deionised ordistilled water.

Shake the mixture vigorously until the two liquids have mixed. Add further water tomake up the final volume to 1000 mI.

Note: The practice of making a strong solution (e.g. 1M) then further diluting this tothe required concentration (e.g. 0.1 M) cannot be applied when using Ethyl Acetate.The required dilution should be made directly as stated above.

Dilution of Sodium Hydroxide

Armfield recommends the use of a 0.1 M solution of Sodium Hydroxide in the CEMMkll reactor. This may be made by adding 4.0g of NaOH to 960ml of deionised waterthen making up the solution to 1000ml.

OPERA TION AS A BATCH REACTORIf the unit is operated as a batch reactor (no continuous feed to the reactor) thentemperature control of the vessel contents will not be possible using the standardarrangement. .>:If it is required to operate in batch mode with the temperature elevated aboveambient then the temperature sensor to be controlled should be the one fitted into theHot Water Circulator vessel. Therefore it may be required to change the temperaturesensor in the PIO loop on the software. The temperature PIO will then regulate thetemperature of the water flowing through the heating coil, preventing overshoot andmaintaining the vessel contents at a steady value. The actual temperature of thevessel contents can be monitored but will not be controlled anymore. Any small offsetin the actual temperature of the reactor contents can be compensated by changingthe set point on the controller by a corresponding amount.

The PID settings for Batch~ation:

Process variable = Reactor Temperatüre.i T2)

Control Variable = Heater

Control Action = Reverse

SP = Chosen by the user IT = O yle time = 100

34

35


PB = O DT= O

As the standard reaction is exothermic the heat generated by the reaction will resultin a rise in temperature of the vessel contents that is unavoidable. If it is required toperform the trial at a temperature below the ambient temperature, the optional chilledwater circulator CW-17 (not supplied) must be connected to the coil in the reactorvessel.

36

Exercise A - To find the reaction rate constant in aContinuous Stirred Tank Reactor

THEORYThe reaction:

NaOH +

Sodium Hydroxide + Ethyl Acetate ---+ Sodium Acetate + Ethyl Alcohol

can be considered equi-molar and first order with respect to both sodium hydroxideand ethyl acetate, i.e. second order overall, within the limits of concentration (O -0.1 M) and temperature (20 - 40°C) studied.

!The reaction carried out in a Continuous Stirred Tank Reactor or Tubular Reactoreventually reaches steady state when a certain amount of conversion of the startingreagents has taken place.

The steady state conditions will vary depending on concentration of reagents,flowrate, volume of reactor and temperature of reaction.

METHODMake up 2.5 litre batches of 0.1 M sodium hydroxide and 2.5 litres of 0.1 M ethylacetate.

IMPORTANT: It is essential when handling these chemicals to wear protectiveclothing, gloves and safety spectacles.

Remove the lids of the reagent vessels and carefully fill with the reagents to a levelapproximately 50mm from the topo Refit the lids.

Start the software using the option of the experiment with heater

Set PIO controller loop according to the settings for a continuous experimentdescribed in operation section.

Adjust the set point of the PIO to 30°C.

Change PIO 'mode of operation' to 'Automatic'

Collection of conductivity data will be until a steady state condition is reached in thereactor and this takes approximately 30 minutes. It is advisable to set the datacollection period to, say, 45 minutes.

Set the pump speed controls to 40 ml/min flowrate in the software.

Fill the concentration of both solutions in their respective boxes in the software.

Fill the volume of the reactor in the box on the software. Set the agitator speedcontroller to 50% in the software.

Press 'Power on' button (or begin taking readings if no computer is being used) andpumps and stirrer will start to work. After a few minutes the temperature sensor tipwill be covered (about 25mm of liquid in reactor) - then press 'Hot Water Circulator'

Exercise A

button and water will start to recirculate through the whole system including thereactor.

It has been determined that the degree of conversion of the reagents affects theconductivity of the reactor contents so that recording the conductivity with respect totime using the Armfield data logger can be used to calculate the amount ofconversion.

INTERPRETATION OF RESUL TS.Having recorded the conductivity of the contents of the reactor over the period of thereaction, the conductivity measurements must now be translated into degree ofconversion of the constituents.

Both sodium hydroxide and sodium acetate contribute conductance to the reactionsolution whilst ethyl acetate and ethyl alcohol do not. The conductivity of a sodiumhydroxide solution at a given concentration and temperature, however, is not thesame as that of a sodium acetate solution at the same molarity and temperature anda relationship has been established allowing conversion to be inferred fromcond uctivity.

The calculations are best carried out using a spreadsheet such as EXCEL so that theresults can be displayed in tabular and graphical formo

Note that the software performs all the calculations needed during experiment.However it is recommended to go through all the procedure and calculations forbetter understanding.

On conclusion of the experiment using the Armfield data logger, a set of readings ofconductivity with time will be sto red in the computer.

At this point, this data can be transferred onto the spreadsheet.

Start the spreadsheet programo

Now enter the following known constants from the experiment using theNomenclature. Ensure use of correct units.

Fa =

a =¡1

b =¡1

c =¡1

T=

v=Using the spreadsheet, calculate the values ofa-; bo, Cm, a:o, 1\cm, 1\ao, 1\am, 1\0 and 1\m from the following formulae:

37

"..-------------------------


FI1.aa = . a).,

F +F,11. v

Cco bo for bo< <lo

Cco <lo for bo2. <lo

A~co 0.070[1+ 0.0284(T-294)] Ceo for T2.294

Aao 0.195[1+ 0.0184(T-294)] <lo for T2.294

Ao Aao assurnesc¿ = O

a:o O for a, < bo

a:o (a, - bo) fcr <lo2. bo

Aaco O 195[ 1+ O. O184(T-294)] a-.o if a:o =i= O

Aco Acco + Aaceo

For the values of each of the above, the spreadsheet can be used to calculate valuesof sodium hydroxide concentration (a1) and sodium acetate concentration (C1) andthe degree of conversion (Xa) and (Xc) for each of the samples of conductivity takenover the period of the experiment.

These can be calculated and listed in columns (use spreadsheet COPY facility)alongside the readings of conductivity using the following equations:

[Aa-Al]e = e

l ,,, l\.. -Au .,

for co = O

eX =_1e e ,,,

for co= O

To calculate the specific rate constant, k:

The overall mass balance at steady-state condition may be written as:

Input - Output ± Reaction = O

i.e. for a reactant a in a reactor of volume V

38

d(Val) 2--- = F . ao - F· al - V .k .aldt

For the continuous reactor operating at steady state the volume may be assumedconstant and

The steady state concentration of NaOH in the reactor (a1) may be used to calculatethe specific rate constant (k).

Exercise A

Comment upon the results obtained. How did temperature affect the reaction rate?and the conversion?

TREATMENT RESULTSConversion of NaOH at different temperatures:

Once the kinetic constant at three different temperatures is known is straightforwardto apply the Arrhenius law and calculate the frequency factor and the activationenergy values for:

Notes:

1. It is recommended that this experiment should be repeated at various othertemperatures to investigate the relationship between the specific rateconstant (k) and the temperature of reaction. If the reactor temperature isbelow ambient Chiller should be required and 'Experiment with Chiller' optionshould be chosen from the software. See below for examples of experimentalresults.

2. It is further recommended that the experiment be repeated using dissimilarflow rates for the caustic soda and ethyl acetate solutions to investigate theeffect that this will have upon the saponification process.

0.80

0.70

0.60

::c 0.50o'" OAO:::x

0.30

0.20

0.10

-"~-~ ~

~

0.00o 200 400 600 800 '1000 '1200 1400 1600 1800

time/sec

39


( E 1ln k = In A---

RT

Plotting Rate constant vs Temperature

k = f (Temperature)

-8.------,------.-----~------._----~----__.0.0( 322 0.00324 0.00326

-8.2 -------------------------------0.00328 OD0330 0.00332

-8.4 f---------- ,---""~---------------------------

.::.r: -8.6 +------------------'''''''=:----------------------s::::- -8.8+-----------------------=-..,;:::---------------

y = -10B49x + 26.90B-9+-----------------------------~~--------9.2 +--------------------------------------"''''''''''

-9.4 "-----------------------------------------

1/T

In A = 26.908 \ 11 3.I:l=4.8S·10 m fmolsec

r¡lé. = 10849R

E = 9 O. 19 KJ ¡mol

Obtention of the reaction rate constant in function of the temperature:

(90.19 'J

k = 4.85 .1011 . e RT

40

0.00334

Exercise B - To determine the effect of inadequate mixingon the reaction rateTHEORYThe rate of reaction is measured by the amount of reactants converted to products ina unit of time. In order for reaction to occur, particles must come into contact and thiscontad must result in interaction. The rate of reaction depends on the collisionfrequency and collision efficiency of particles of the reacting substances. Thesefactors are optimised by thorough mixing of the reactants using stirrers and baffleswithin the reactor. Inefficient mixing will result in reduced reaction rates.

Considering the reaction between sodium hydroxide and ethyl acetate, if the initialconcentrations are equal (both 80) and the conversion (Xa) then the concentrationsare as follows:

METHODRepeat Exercise A after removing the baffles from the reactor. This is achieved byremoving the conductivity and temperature probes then removing the lid of thereactor. The baffle arrangement simply lifts out.

Repeat the experiment with baffles removed and no stirring action.

Three sets of data will be obtained:

a. Stirred reactor with baffle (see Exercise A)

b. Stirred reactor, no baffle

c. Un-stirred reactor, no baffle

Graphs of the reaction conversion with time can be plotted using the data logger (orusing the manual readings obtained if not using the logger).

Comment on the results obtained. How did removal of the baffle affect the reactionrate? What effect does stirring have on the reaction rate?

41

42

Exercise e -Determination of the Residence Time usingtracer techniques

THEORYEffect of a step input change, calculation of the average residence time.

If C = concentration in reactor at time t after input step change

Ca = concentration of the input

( 'J,.-, IrC=I.~o 1-18Then where tr = time constant

c [ -;)-= 1-18 "eo

In r1 - ~J= - ~ . tCn Ir'- .

Hence te may be found graphically.

METHODMake up 2.5 litres of a solution of 0.1 M KCL and fill one of the feed vessels. Fill theother feed vessel with demineralised water.

Using the Armfield data logger, initiate the program

Set the reactor stirrer to a speed of '50%' and press 'Power on' button to start it up.The experiment can be carried out at room temperature initially. If other reactortemperatures are required this is achieved using the hot water circulator and settingthe PIO temperature controller in the software as detailed in previous experiments.

Start the water feed pump by setting the pump speed control to maximum in order tofill the reactor to the overflow as quickly as possible. When the reactor is full, stop thefeed pump.

Start the KCL solution feed pump by setting the pump speed to 100 ml/min.

The conductivity of the reactor contents will begin to increase and, after a period ofapproximately 45 minutes to 1 hour, will approach the conductivity of the feedsolution and will reach the steady state.

On conclusion of the experiment using the Armfield data logger, a set of readings ofconductivity with time among other calculations will be sto red in the computer.

At this point, only conductivity with time data can be transferred onto thespreadsheet.

Start the spreadsheet programo

Exercise C

e(1-- )

Plot this value against t and calculate the Neperian logarithm of C¿

TREATMENT RESULTSC 1\

The normalisation of the concentration eo A o can be plotted against time:=

090,-------------------------------------------------020+-------------------------------------------------0.70-I---------------------------------------.::M~~~~=-

OBO+---------------------------~~~~-------------

e 050+---------------------~p~------------------------O---O 0.~+---------------=6~------------------------------

Calculate N/\.o which is the equivalent to C/Co where /\. is the conductivity at time t,and /\.0 is the conductivity of KCL at the steady state (maximum conductivityreached), for readings of t throughout the experiment.

ln(l-~)Plot C¿ vs time and calculate the slope (straight line graph passingthrough the origin). The slope is the average residence time tR which should be equal

V

to F where Vis the reactor volume and F is the total flow rate into the reactor.

030+----------=~------------------------------------020+-----~~----------------------------------------0.10+----;#ii"----------------------------------------------

ODO~------_.--------~------_r--------r_------_r----o LOO 4CO 000 800 1000

timeJs ec

To calculate the experimental residence time:

e(1- ~ )

oCalculate the Neperian Logarithm of

Plot(el

in 1--e,J vs time and calculate the slope

43


400 600 800 1000 1200-0.2000

-0.4000

-0.6000

Z -0.8000...J

-1.0000= -O.0013x

Fi = 0.9999-1.2000

-1.4000

-1.6000

1- 0.0013 =--tr

)

ti sec

I o Series·l - Linear (Series1) I

tr = 769.23 sec

The Average Residence Time for a working volume of 1369 mi and a working flowrate of 106.5 ml/min:

-r = Vreactor = 1369 = 771 secFlowrate 106.5

The difference between the theoretical and the experimental value may be caused byexperimental errors, such inaccuracies on the measurement of the flowrate or reactorworking volume, etc.

44

Tel: (732) 928 3332Fax: (732) 928 3542Email: [email protected]

Contact Details for Further Information

Main Offiee: Armfield Limited

Bridge HouseWest StreetRingwoodHampshireEngland BH24 1DY

Tel: +44 (0)1425478781Fax: +44 (0)1425470916Email: [email protected]

[email protected]: http://www.armfield.eo.uk

US Offiee: Armfield Ine.

436 West Commodore Blvd (#2)Jaekson, NJ 08527

45

Tel: _ Fax: E-mail: _

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THANKYOUfor choosing Armfield equipmenf for your specialengineering feaching or research requiremenf.If you would like fo receive updafed informafion on Armfieldequipmenf, please fill in your defails be/ow and refurn fhis card:

Name: Position:

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Your comments:

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Tel: +44 1425478781 - Fax: +44 1425470916 - E-mail: [email protected] - www.armfield.co.uk

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Tel: +44 1425478781 «Fax: +44 1425470916 - E-mail: [email protected] - www.armfieia.co.uk

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Armfield products are distributed throughout the world.It is our poli€y in most counmes to deal direct or through proven andaccredited sales agents, who after suitable approval, may becomeex(/usive representatives. In exchange for thls excJusivity theyare required to offer a comprehensive service incJuding thehighest degree of after sales support.

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