scirocco 2000 - university of …...installation (in case the system has to be moved after its...

I N S T R U M E N T S

Printed in England MRK0866-01Malvern Instruments Limited

Enigma Business Park

Grovewood Road, Malvern

Worcs, WR14 1XZ, U.K.

Tel: +44 (0) 1684 892456

Fax: +44 (0) 1684 892789

www.malvern.com

user manual

Scirocco 2000

Scirocco 2000User Manual

MAN0386 Issue 1.0 March 2007

MAN0386-1.0 Scirocco 2000.book Page i Friday, March 16, 2007 4:15 PM

MAN0386-1.0 Scirocco 2000.book Page ii Friday, March 16, 2007 4:15 PM

© Malvern Instruments Ltd. 2007

Malvern Instruments makes every effort to ensure that this document is correct. However, due to Malvern Instruments’ policy of continual product development we are unable to guarantee the accuracy of this, or any other document after the date of publication. We therefore disclaim all liability for any changes, errors or omissions after the date of publication.

No reproduction or transmission of any part of this publication is allowed without the express written permission of Malvern Instruments Ltd.

Head office:

Malvern Instruments Ltd.Enigma Business Park,Grovewood Road,Malvern,Worcestershire WR14 1XZUnited Kingdom.

Tel + [44] (0)1684-892456Fax + [44] (0)1684-892789

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Perlast is a registered trademark of Precision Polymer Engineering.

Printed in England

Table of Contents


Part 1 - Operator’s Guide

Introduction to this manualIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1Access to the instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2Assumed information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3Where to get help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

Hardware featuresIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1What the dispersion unit does . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1How the dispersion unit works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2How the dispersion unit is controlled . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3Features of the Scirocco 2000. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3Scirocco 2000 with hopper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12

Software featuresIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1Making a measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1Manually controlling the dispersion unit . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2Writing an SOP for the dispersion unit . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

Making a measurementIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1Dry powder measurement guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1Making a measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Scirocco 2000 Page i

Table of Contents Scirocco 2000


Part 2 - Appendices

SpecificationSpecification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1

Chemical compatibilityIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1Components in contact with sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

Regulatory statementsCE Declaration of Conformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-2

Index

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Part 1 - Operator’s Guide

1


Introduction to this manual

IntroductionThis manual covers the operation of the Scirocco 2000 sample dispersion unit:

This manual is a supplement to the following manuals:

Mastersizer 2000 User Manual (termed “the main User Manual”).

Mastersizer 2000 Essentials Manual (termed “the Essentials Manual”).

This dispersion unit manual focuses on some specific issues of the dispersion unit that are not covered by the above manuals. It aims to:

Describe what the dispersion unit is and explain in simple terms how it works.

Identify the physical features of the dispersion unit.

Describe the software and explain how to use the dispersion unit to make a measurement on the system.

Warning!The dispersion unit or the samples to be measured may be hazardous if misused. Users must read the Health and Safety information in the Essentials Manual before operating the system.

We recommend that users who have never operated a Malvern particle analyser before read this manual fully before starting the first measurement.

Instrument Model number

Scirocco 2000 (stainless steel venturi) ADA2000

Scirocco 2000 (ceramic venturi) ADA2001

Hopper for Scirocco 2000 option DPF2267

Scirocco 2000 Page 1-1

Chapter 1 Introduction to this manual1


Those who are more familiar with particle size analysers may wish to jump straight to Chapter 4 of the main User Manual which gives details on making measure-ments. However, the importance of sample preparation before measurement can-not be overstated so we recommend reading the chapter on sample preparation (Chapter 8 of the main User Manual) as a priority.

Warning!Static discharge can occur around the exit and feed pipe regions of the unit under certain combinations of material, flow rate and humidity. If this is a concern in your application, contact your Malvern supplier.

Access to the instrumentWithin this manual, reference is made to the various people who will have access to the dispersion unit. The following is a list of these people and their responsibilities:

Malvern personnelMalvern personnel (service engineers, representatives, etc.) have full access to the dispersion unit and are authorised to perform all service procedures that may require the removal of the covers.

SupervisorThe supervisor is the person responsible for the management/safety of the disper-sion unit and of its operation. The supervisor is responsible for the training of the operators. The supervisor can perform all user maintenance routines identified in Chapter 4 of the Essentials Manual, including changing the fuses.

Warning!The supervisor/operator must never remove the covers of the instrument or dispersion unit. Removal of the covers by unauthorised personnel will invalidate the warranty of the dispersion unit.

OperatorAn operator is a person trained in the use of the dispersion unit. The operator can perform all user maintenance routines identified in Chapter 4 of the Essentials Manual, except for changing the fuses.

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Introduction to this manual Chapter 1


Warning!Failure to follow this guideline could result in exposure to hazardous voltages.

Assumed information

Naming conventionWithin this manual:

The Mastersizer 2000 optical bench is referred to as “the optical bench” or “the instrument”.

The sample dispersion units are referred to in full (“the Scirocco 2000”) or as “the dispersion unit”.

The combination of the optical bench, one or more dispersion units and the computer is referred to as “the system”.

The hopper-equipped Scirocco 2000 is identified as a “hopper instrument”.

Menu commandsMenu commands from the Malvern software are referred to in the form main menu-menu item. As an example, the command Configure-New SOP refers to selecting the New SOP item in the Configure menu. The same rules apply for sub-menus of sub-menus, so that Tools-Options-Instrument Port refers to the Instrument Port item in the Options sub-menu, which itself is a sub-menu of the Tools menu. Menu commands are always shown in bold text.

Where to get helpFull details on where and how to obtain help can be found in Chapter 1 of the main User Manual.

The Essentials Manual gives information on the following:

Site requirements.

Health and Safety.

Maintenance.

Installation (in case the system has to be moved after its initial installation by Malvern Instruments personnel).


Chapter 1 Introduction to this manual


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2


Hardware features

IntroductionThis chapter describes the physical features of the dispersion unit. It covers:

What the dispersion unit does.

How the dispersion unit works.

How the dispersion unit is controlled.

The physical features of the Scirocco 2000 in detail.

The Scirocco 2000 with hopper option.

What the dispersion unit doesThe sole purpose of any sample dispersion unit is to prepare the sample and then deliver it to the optical bench so that it can be measured.

The Scirocco 2000 allows the Mastersizer 2000 to be used for particle-in-gas parti-cle sizing (in the majority of cases the gas will be air).

The materials used in the manufacture of the dispersion unit maximise the range of samples which can be handled. Variable air pressure allows a wide range of particle sizes and densities to be suspended and delivered to the optical bench.


Chapter 2 Hardware features2


How the dispersion unit worksThis diagram shows the features of the dispersion unit:

ill 7765

The dry powder sample is manually placed in the sample tray with the air supply and vacuum extraction system connected. When the sample tray is vibrated the sample travels down the tray until it eventually falls into the main feed mechanism. The rate at which the sample is fed is governed by the amplitude of vibration on the sample tray (controlled from the software) and also by the gap between the feed gates on the sample tray.

At the entrance to the main feed mechanism is a wire sieve filled with ball bearings . The ball bearings smooth the flow of sample and also help to break up loose agglomerates within the sample.

As the sample falls through the sieve it is accelerated by compressed air within a venturi where agglomerates are dispersed. The sample is then directed through the air cell fitted to the Mastersizer, where it is measured and then collected by the vacuum extracting system at the rear of the air cell.

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Hardware features Chapter 2


How the dispersion unit is controlledThe dispersion unit is controlled using a single software dialogue with sliders for the air pressure, sample tray vibration feed rate, and (for hopper instruments) the hopper feed rate. (Chapter 3 has details.) When controlled through a Standard Operating Procedure (SOP), the software tells the user what value to set for each parameter.

The system automatically detects which dispersion unit and cell are connected. If more than one dispersion unit is connected, the system will detect all dispersion units connected but only the dispersion unit that has its cell installed on the optical bench will be “active”.

Features of the Scirocco 2000The illustration below identifies the main features of the dispersion unit:

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Chapter 2 Hardware features


Sample tray areaThe sample tray area is where the sample is added to the dispersion unit. Sample feeds down the sample tray as it is vibrated. Three sizes of sample tray are available for different applications. More details of the sample tray area are given below.

Status indicatorThe status indicator illuminates in one of three colours when the dispersion unit is powered up:

Green if the dispersion unit is functioning correctly and its cell has been loaded into the optical bench (i.e. the dispersion unit is “active”).

Amber if the dispersion unit is functioning correctly but its cell has not been loaded into the optical bench (i.e. the dispersion unit is at “standby”).

Red if the dispersion unit detects an error. If an error message does not appear on the screen, selecting Configure-Accessories will display the dispersion unit control dialogue which should show the error.

Sample area lidThe sample area lid is primarily a safety feature that reduces the sound emissions from the dispersion unit. The lid must be locked using the central catch to ensure that sound emissions are reduced to an adequate level.

The lid is interlocked so the dispersion unit automatically returns to standby mode if it is opened during a measurement. Unless there is a hopper, it is therefore important that the sample is added to the sample tray before the measurement is started. With hopper instruments, the sample can be added to the hopper as the measurement proceeds.

Rear panelThe rear panel contains all services and communication connectors for the disper-sion unit. More details are given later in this chapter.

Sample exit portThis is the port where the sample leaves the dispersion unit. It is connected to the air cell via a flexible tube. The tube must be removed from this port if the cell is to be stored in the cell holder. This prevents damage to the ceramic outlet nozzle.

Air cellThe air cell is used to confine the sample as it passes through the analyser beam in the optical bench. More details are given later in this chapter.

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Vacuum switcher boxThe vacuum switcher box is a control box used to turn on the primary vacuum unit for the dry cell and the secondary vacuum unit used for cleaning. The switcher box is controlled from the software. More details of its features are given below.

Vacuum unitThe vacuum unit removes the sample from the cell exhaust once it has been meas-ured.

Sample tray areaThe sample tray area holds a vibrating tray that holds the sample. Sample feeds down the sample tray as it is vibrated. This illustration shows the main features:

ill 4942

Sample trayThe sample tray receives the sample to be measured. Three sample trays are availa-ble for the Scirocco. Each type is individually encoded so that, when it is attached to the dispersion unit, it is automatically detected and reported in the sample records. The three tray types are:

General purpose tray – the standard tray provided with the Scirocco 2000, this has an adjustable slit to regulate the flow of sample. This is most suitable for free-flowing materials and materials having broad size distribu-tions (greater than 1 to 300 microns) where larger samples need to be measured to obtain statistical significance.

Micro volume tray – this is designed for pharmaceutical materials where very little material is available. The smallness of the tray removes the temp-tation to overload it. The tray has a single slit width which is recorded in the sample details and in the SOP.

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This tray is not suitable for samples having broad size distributions unless several repeat measurements are made. Repeat measurement tests need to be carried out to determine the exact number of repeat measurements to give the required standard of repeatability.

Small volume tray – if the small size of the micro volume tray proves to be a problem in terms of repeatability, the small volume tray provides a compromise. Again, it has a fixed width slit to eliminate one source of method variation.

GatesThe gates of the general purpose tray are used as a method of controlling the flow rate of the sample by varying the aperture between them. The gates are locked in position by the knurled locking screws.

On hopper instruments the sample tray has a one piece guillotine style gate con-trolling the flow rate of the sample. To adjust this loosen the M3 Allen screws that secure the gate then move the gate up or down to the desired position. Use a 1.5mm Allen key to adjust this, securing the screws afterwards.

SieveThe ball bearings in the wire sieve at the entrance to the feed mechanism smooth the flow of the sample as they effectively store the sample within the array for a short period. The ball bearings also break up loose agglomerates in the sample.

One fine and one coarse sieve are provided with the dispersion unit.

Tray locking screwThe sample tray is locked in position by tightening the locking screw.

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Rear panelThis illustration shows the main features of the rear panel:

ill 4979

Mains power supplyThe mains power supply is a standard IEC socket that supplies mains power to the dispersion unit. The connector also houses the dispersion unit’s fuses and on/off switch.

Auxiliary connectorThe auxiliary connector is connected to the vacuum switcher box.

Accessory comms “in” connectorThe communications cable from the optical bench or from another dispersion unit connects here.

Accessory comms “out” connectorIf more than one dispersion unit is connected to the system and this is the first dis-persion unit in-line, a communication cable will be connected from here to the “accessory comms - in” connector of the second dispersion unit.

Caution!A termination plug must be fitted to this connector if this is the only dis-persion unit connected or it is the last dispersion unit in the line.

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Air in connectorThe compressed air line is connected to this. The compressed air is used to disperse the sample. The input range is from 6-8 bar.

Caution!The dispersion unit may be permanently damaged if the compressed air line is not clean, dry and free from oil (see the Site Requirements for details).

Vacuum monitor connectorThe vacuum monitor connector is connected to the rear of the air cell and used to detect whether the vacuum unit is working. This is a safety device - it ensures that the sample will not be fed into the system until the vacuum unit is capable of safely taking it away. Do not apply a pressure greater than +0.3 bar g to this input.

Air cell

Caution!The air cell is an optical device. Treat it carefully as you would an expen-sive camera. Scratches to the surfaces of the cell may affect performance.

The cell passes the sample through the analyser beam of the optical bench so that it can be measured. The cell windows are part of the optical path of the system and should be kept clean and free from scratches at all times. Refer to Chapter 4 for details of cleaning/maintaining the cell.

The cell is encoded so the system detects and identifies it when it is loaded into the optical bench. This diagram shows the features of the cell:

Page 2-8 MAN 0386



ill 4944

Noise protection boxThis dampens any noise emissions from the air cell.

Sample inletThe sample tube from the dispersion unit is connected to this inlet

Locking handleThe cell locking handle must be rotated anti-clockwise to lock the cell in place on the optical bench. To remove the cell, disconnect the sample inlet tube from the sample inlet, rotate the handle clockwise and lift the cell clear.

Warning!Never attempt to lift the optical bench by the locking handle of the cell. See the Health and Safety information for correct moving techniques.

Cell shroudThe cell shroud prevents stray light entering the measurement area and affecting a measurement. More importantly, it stops human access to laser radiation. The sys-tem should never be used if the cell shroud is damaged.

Cell windowsThe cell windows allow the analyser beam of the optical bench to pass through the cell and hence the particle field. The cell windows can be removed to allow clean-

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ing (the cell window tool used to remove the window is located within the cell holder). The cell windows are delicate and should be treated with caution - refer to the Essentials Manual for details on cleaning these windows.

Vacuum monitor connectorA tube from this connector attaches to the vacuum monitor connector on the rear panel of the dispersion unit. This senses whether the vacuum unit is working. This is a fail-safe device that prevents the sample being fed until the vacuum unit is on, allowing the powder to be safely disposed of.

Earth leadThis earth lead must always be connected. It prevents the particles being charged.

Exhaust connectorThe vacuum tube from the vacuum unit is connected here. A vacuum unit must be used to prevent samples being discharged into the laboratory.

Cell holderThe Mastersizer system allows more than one sample dispersion unit to be con-nected at once. The cell holder provides a convenient storage location for the cell (and the window removal tool) if another dispersion unit is being used.

The cell holder has a special fixing located on the left of the optical bench especially for air cells. See for details on how to fit the holder.

Disconnect the sample tube to the cell before storing the cell in the cell holder.

Cell holder fixingThere is a fixing plate under the cell holder which can be extended by undoing the two hand screws and sliding the plate out. Re-tighten the hand screws to lock the plate in place.

The cell holder can then be attached to the left side of the optical bench by locating the fixing plate onto the two lugs on the underside of the optical bench.

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Vacuum switcher boxThis diagram shows the features of the vacuum switcher box:

ill 4941

“From dry power feeder” connectorThis connector connects to the dispersion unit’s Auxiliary connector. The vacuum unit is controlled via this connector.

Fuse holderThis holds the vacuum switcher box fuse. Any replacement fuse must be of the correct type and value (see the cover of the vacuum switcher box for details).

Mains inlet socketThe mains power supply is a standard IEC socket that supplies mains power to the switcher box.

Mains outlet socketThe mains power outlet is connected to the vacuum unit.

Warning!The warning symbol near this socket is there to warn that this power socket is switched on and off by computer control. The operator must be aware that this power socket may be powered unexpectedly.

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Scirocco 2000 with hopperThe hopper instrument is a modified version of the Scirocco 2000, specifically designed for the needs of customers in the cement and bulk chemical industries. Its features are shown below:

ill 7397

Changes from the standard Scirocco 2000 are:

New lid assembly This has an integral hopper assembly and an auxiliary vacuum exit.

Hopper assembly The hopper assembly is in the sample lid that sits above the sample tray. This com-prises a sample funnel and a cascade assembly:

Sample funnel – two sample funnels which fit into the hopper assembly are available, with fine or coarse meshes suitable for use with different sizes of sample.

The sample is placed on a mesh inside the funnel and vibrated by a motor fitted under the lid, so a steady stream of sample is deposited on the sample tray.

Cascade assembly – this is fitted beneath the funnel. It controls the rate at which sample is delivered to the sample tray.

As with the sample tray feed rate, the vibration rate of the hopper can be set from the SOP, allowing different feed rates to be used for different samples.

Auxiliary vacuum portThe auxiliary vacuum port allows a secondary vacuum cleaner to be attached to the unit in order to remove any excess sample from the sample tray at the end of the measurement.

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One piece sample traySimilar in application to the general-purpose tray described earlier, this tray has a narrow sample area to guide the sample directly towards the sieve. A one-piece 'guillotine' style gate controls the sample flow.

Vacuum switcher boxHopper instruments use a larger switcher box. This has a second mains power outlet socket, required for connecting the second vacuum unit used to remove any excess sample from the sample tray after the measurement has finished.




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3


Software features

IntroductionThis chapter describes the features of the software which are specific to the disper-sion unit. It covers:

Making a measurement – the basics of making a measurement using the dis-persion unit.

Manually controlling the dispersion unit.

Writing an SOP for the dispersion unit.

Making a measurementMaking a measurement is fully documented in Chapter 4 of the main User Man-ual. Refer to that manual for details.

The dispersion unit can either be controlled manually or automatically by running a Standard Operating Procedure (SOP). The system automatically detects which dispersion unit and cell is connected. If more than one dispersion unit is con-nected, the system detects all dispersion units connected, but only the dispersion unit that has its cell installed on the optical bench will be “active”.


Chapter 3 Software features3


Manually controlling the dispersion unitAll Scirocco 2000 functions can be controlled directly from the Dry Accessory dialogue (accessed by selecting Configure-accessories). The dialogue is shown below:

ill 7771

This example shows the hopper-equipped version of the dialogue. The dialogue allows the user to alter, by using the relevant slider bar, the Air Pressure, sample tray vibration Feed Rate, and (for hopper instruments) the Hopper Feed rate.

The dialogue also allows the user to turn on the feed mechanism and air pressure. Status indicators give information such as whether the tray lid is open/closed and which sample tray is fitted, as well as reporting any errors.

Air pressure controlThe Scirocco 2000 uses compressed air to transport and suspend the particles of the sample as they pass through the air cell. High air pressure settings can also help break up agglomerates. The air pressure can be controlled up to a pressure of 4 bar.

The optimum air pressure setting depends on your sample, so a few trial measure-ments are recommended. A typical starting air pressure is between 1 and 3 bar. If the sample is fragile, for example freeze dried coffee, use a lower pressure. If the sample is dense or cohesive, use a higher pressure.

If the air pressure is set too high this may physically change the particle size, giving an incorrect result.

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Software features Chapter 3


Use one of the following methods to ensure that the correct air pressure is being used:

Perform a number of measurements at different air pressures and look for a ‘plateau’ of stable results. Choose the lowest air pressure commensurate with a stable result.

If the sample can be recovered after measurement, and shows no significant change when re-measured, the air pressure is acceptable.

If the sample can also be measured using a wet dispersion unit, and there is no significant difference in the result, the air pressure setting is acceptable.

The air pressure control will not operate until the Air flow radio button is selected from the Mode area of the dialogue.

Feed rate controlThe Scirocco 2000 uses a vibrating tray to feed the sample into the dispersion sys-tem. The rate at which sample is fed is governed by the vibration amplitude and the type of tray fitted.

Adjust the feed rate to produce a steady flow of sample into the dispersion system and to obtain the optimum sample concentration through the measurement cell. If the feed rate is too high, the sample concentration may become too high and any agglomerates may not disperse correctly. If the feed rate is too low, the concentra-tion may become too low and/or the sample flow may become intermittent. The General Purpose tray has an adjustable slit to help maintain a steady sample feed.

Sample concentration is monitored using the obscuration reading in the Meas-urement Display dialogue.

The feed rate control will not operate until the Feed radio button is selected from the Mode area of the dialogue.

Mode selectionThe Scirocco 2000 is turned on/off using the mode buttons: Standby, Air flow and Feed. The status line describes the current state of the Scirocco 2000. The but-tons operate as follows:

Standby – sets the unit into an inactive mode. The unit may be automatically set to this mode if an error condition is detected.

Air flow – turns on the vacuum and checks the minimum vacuum level is reached, then checks the air pressure is correct and turns on the air flow.


Chapter 3 Software features


A progress bar indicates the state of the air control sequence. The segments have the following meaning:

Feed – turns on the vibration of the tray. If the air flow is not already on, the vacuum and air flow are turned on first. The associated indicator is illuminated green when the requested vibration level is reached.

Error indicatorsAny error detected by the system will return the unit to standby mode. Malfunc-tions are shown by red illuminated indicator boxes. The type of error will also be displayed in the status area of the dialogue.

The system monitors the operation of the following devices:

Segment 1 Unit in standby mode

Segment 2 Waiting for vacuum confirmation

Segment 3 Waiting for air pressure confirmation

Segment 4 Not used

Segment 5 Air flow on.

Device Fault condition Possible cause

Vacuum No vacuum detected. Fuse blown in switcher box.

Vacuum unit not switched on.

Cable to switcher box not fitted.

Vacuum unit pipe not connected.

Power cable to switcher box not fitted.

Insufficient vacuum (e.g. clogged bag).

Lead to vacuum unit not fitted.

Sense tube between air cell and dispersion unit not fitted.

Air Pressure Air pressure not within 10% of full scale pres-sure (i.e. ±0.4 bar of requested pressure).

Air supply not on, or pressure low.

Air supply pipe not connected.

Air supply pipe blocked.

Vibrator Monitored level not within 10% of requested level.

Tray jammed.

Hardware failure.

Tray Invalid tray code. No tray fitted.

Tray fitted incorrectly (not screwed in).

Tray detection hardware failure.

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If an error is not corrected by the above suggestions, contact the local Malvern rep-resentative.

Sample tray and lid indicatorsThese indicators display which sample tray is fitted and whether the lid is open.

Hopper Feed controlThe hopper is a pre-disperser. Its purpose is to deliver a steady amount of powder to the sample tray, so that the amount of powder passing through the venturi remains roughly constant. This prevents surges in obscuration and poor dispersion caused by passing too much material through the venturi system.

Approximate starting hopper feed rates are 40% to 45% for a material such as cement, but every product is different so the appropriate SOP settings may differ.




Writing an SOP for the dispersion unitAn SOP can be configured to control all settings for the dispersion unit automati-cally. When an SOP is run, the software will (depending on how the SOP has been set up) automatically set the air pressure and feed rates to a pre-defined setting and run through a measurement sequence. The SOP will even report if the wrong cell or dispersion unit is fitted.

The SOP Wizard is described in full in the main User Manual. There are ten dialogues in all but here we just describe those which have parameters specific to the Scirocco 2000. These are the Sampler Selection, Sampler Settings and Measurement Cycles dialogues.

Ensure that all systems an SOP is distributed to have the dispersion unit connected.

Sampler Selection dialogueThe Sampler Selection dialogue is shown below.

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Select the dispersion unit to use from the drop down list . All dispersion units available are listed, even those that are not attached to the system. This enables an SOP to be written remotely from the system.

Under the Sample handling unit options specify the type of venturi fitted. There are two types:

Metal – suitable for most applications.

Ceramic – for abrasive materials.

NoteThe unit’s A/B identity must be set for the correct venturi. It must be set to A for a metal venturi and B for ceramic. On older systems this switch was not used; if in doubt, select Original Configuration to disable the ven-turi type check. Contact the Malvern representative if required to switch between the types of venturi.

Sampler Settings dialogueThe Sampler Settings dialogue controls the feed rate and air pressure settings for the dispersion unit. This dialogue changes depending on the dispersion unit selected in the Sampler Selection dialogue. This diagram shows the dialogue for the Scirocco 2000:

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Tray selectionThis lists all the sample trays available. All systems the SOP is distributed to must have the tray selected in the list fitted.

Vibration Feed Rate controlThe Scirocco 2000 uses a vibrating tray to feed the sample into the dispersion sys-tem. The rate at which sample is fed is governed by the vibration amplitude and the type of tray fitted.

Adjust the feed rate to produce a steady flow of sample into the dispersion system and to obtain the optimum sample concentration through the measurement cell. If the feed rate is too high the sample concentration may become too high and any agglomerates may not disperse correctly. If the feed rate is too low the concentra-tion may become too low and/or the sample flow may become intermittent. The General Purpose tray has an adjustable slit to help maintain a steady sample feed.

Sample concentration is monitored using the obscuration reading in the Meas-urement Display dialogue.

Dispersive Air Pressure controlThe Scirocco 2000 uses compressed air to transport and suspend the particles of the sample as they pass through the air cell. High air pressure settings can also help break up agglomerates. The air pressure can be controlled over the range 0 to 4 bar (atmospheric pressure is approximately one bar).

The optimum air pressure setting depends on the sample, so a few trial measure-ments are recommended. A typical starting air pressure is between 1 and 3 bar. If the sample is fragile, for example freeze dried coffee, use a lower pressure. If the sample is dense or cohesive use a higher pressure.

If the air pressure is set too high this may physically change the particle size, giving an incorrect result. One of the following methods may be used to ensure that the correct air pressure is being used:

If the sample can also be measured using a wet dispersion unit, and there is no significant difference in the result, the air pressure setting is acceptable.

Perform a number of measurements at different air pressures and look for a ‘plateau’ of stable results. Choose the lowest air pressure commensurate with a stable result.

NoteApplication Notes available at www.Malvern.com describe the process of method development for dry powder dispersion.

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Page 3-8 MAN 0386



Hopper Feed Rate (hopper instruments only)The hopper is a pre-disperser. Its purpose is to deliver a steady amount of powder to the sample tray, so that the amount of powder passing through the venturi remains roughly constant. This prevents any surging in obscuration, and any poor dispersion caused by passing too much material through the venturi system.

Aim to set a rate that delivers a steady amount of powder:

1. Initially set the Vibration Feed Rate to an appropriate value (around 30%).

2. Change the Hopper Feed Rate until enough material to produce a steady line of powder is passed down the tray. This is then the rate to use in an SOP.

Approximate starting Hopper Feed Rates are 40% to 45% for a materials such as cement, but every product is different so the appropriate SOP settings for specific products may differ.




Measurement Cycles dialogueThe Measurement Cycles dialogue allows the system to be set up to perform multiple measurements of a sample. It also defines the cleaning sequence used after a measurement has been completed.

Excess sample often remains on the tray and has to be removed manually. The Cleaning section of the dialogue enables this excess sample to be fed through the system into the vacuum cleaner. In a hopper-equipped Scirocco, the excess sample can be withdrawn directly from the sample tray into a second vacuum unit attached to the sample lid.

The cleaning cycle becomes active when the Cleaning required check box is ena-bled. The user must then set:

The Clean Duration, the time beyond the measurement period during which the vibrating tray, compressed air supply and vacuum cleaner are left running in order to clear the sample from the tray.

The Vibration Feed Rate to use during the clean cycle.

The Dispersive Air Pressure required to convey the sample through the cell during cleaning.

In addition, if a second vacuum cleaner has been installed on a hopper Scirocco, selecting the Second vacuum fitted option triggers the second vacuum cleaner at the end of the sample measurement and remove all excess sample directly from the sample tray during the clean procedure.

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The Advanced - Measurement dialogueThe system can be configured to measure only when certain obscuration condi-tions are met. Open the Advanced - Measurement dialogue by clicking the Measurement button on the Measurement dialogue.

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The Advanced - Measurement dialogue allows configuring of Obscuration limits and Autostart, Obscuration Filtering (where measurements are only taken when obscuration lies between certain limits) and Red Only Measure-ment. These are described in Chapter 9 of the main User manual, but this sec-tion gives additional information specific to dry powder measurements.

The tabs on the dialogue are:

Obscuration limitsCheck the Use default limits box to set the limits to default values of between 0.5% and 6% for a dry dispersion unit. Select the Raise alarm... box to flag when integrated obscuration is out of range.

This tab only defines the limits - the Obscuration filtering tab imposes the defined limits.

1

2

3

4




NoteApplication Notes available at www.Malvern.com describe the process of method development for dry powder dispersion, including selection of obscuration limits.

AutostartAutostart is used to ensure that no measurements are started until the dispersion is stable. Dry measurements always exhibit a range of fluctuation so the Autostart feature is not generally used for these.

Obscuration filteringThis facility is particularly useful when the sample concentration is liable to some degree of fluctuation as is often the case with dry powder measurements. Selecting the Only include snaps with values within obscuration limits check box effectively turns on the obscuration limits set in above.

For dry powder measurements practical limits are 0.5% and 6% but exact settings can only be found by experimentation.

In the event that a totally inappropriate feed rate is set so that the obscuration sel-dom (if ever) falls within the desired limits, a time-out allows the user to exit the measurement. Do not set this so long as to give the measurement routine the appearance of having hung up, but it should be sufficiently long to allow a fair chance of sample of the required concentration passing through the measurement zone.

The user is strongly advised to adjust the feed rate so that the obscuration falls between the preset limits for the duration of the measurement.

If a measurement times out the number of measurement snaps is recorded e.g. it will be reported that “1760 of 2000snaps” were captured.

Red Only MeasurementThe options on this tab are not available as the blue light source is not used for dry powder measurements.

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4


Making a measurement

Introduction This chapter describes how to make a measurement using a Scirocco 2000. It cov-ers:

Dry powder measurement guidelines.

Making a measurement – important differences from the procedure described in Chapter 4 of the main User Manual.

Dry powder measurement guidelinesTo obtain good repeatable dry powder measurements, ensure that the individual particles are well dispersed in the air flow and that they are transported through the measurement region at a suitable steady rate and concentration.

The energy used to disperse the particles is mainly controlled by the air pressure. The concentration is largely determined by the rate at which powder is fed into the air stream.

The ease of dispersion varies greatly between materials. Cohesive materials such as magnesium stearate require much more dispersion energy than free flowing sam-ples such as glass beads. The same material can vary with humidity, temperature and degree of compaction.

However, do not always simply use the maximum dispersing energy. Many phar-maceutical and food materials are fragile, as are substances like raw ceramics. Too much energy will break up the primary particles.

Some cohesive materials may be compacted onto surfaces by high pressure and flake off as agglomerates.


Chapter 4 Making a measurement4


Control of concentration is also important. Too little sample means measuring mainly background noise. Too much sample means the measurement is distorted by multiple scattering.

Making a measurementMaking manual and SOP measurements using the Scirocco 2000 is basically the same as discussed in Chapter 4 of the main User Manual, but with two impor-tant differences:

As the lid to the sample tray is interlocked for safety, if the lid is opened during a measurement, the dispersion unit automatically shuts down to its standby mode. Because of this, the sample must be added to the sample tray before the measurement is started.

Secondly, the Add sample tab of the measurement display is not typically used. Instead, obscuration triggering is used to start a measurement. Obscura-tion triggering is where a measurement is only started when the obscuration of the sample is between two preset values.

To make a basic manual measurement:1. Open the lid to the sample area and add the sample to the sample tray. Add the

sample to the centre of the tray, especially for free-flowing samples, to prevent the sample from self-feeding.

2. Close and lock the lid.

3. Alter the air pressure and feed rate setting by selecting Configure-Accesso-ries... and moving the appropriate slider. Note that the air or feeder will not actually start until the Airflow or Feed radio buttons are selected in the Mode section of the dialogue. Position the control dialogue to the left of the screen where it can be seen and readily accessed.

4. Select Measure-Manual to display the Measurement display. The system will automatically measure an electrical background, align the system and then measure the optical background.

5. Select the Options button to change any settings for the measurement. Choose:

The Material tab to define the sample that is being measured.

The Measurement tab to set the measurement time.

Press the Measurement button in the Measurement tab to set the obscuration settings.

Page 4-2 MAN 0386

Making a measurement Chapter 4


6. In the Advanced - Measurement dialogue, shown below, select the Only include measurements with values within obscuration limits check box. Set the obscuration limits (typically set these to between 0.5% and 6%):

Select OK.

7. Press the Next button in the Measurement display to access the Add sample tab. This tab is not be needed as the measurement will be started by obscura-tion triggering. Press the Next button again to view the Measure sample tab.

8. Press the Start button to start the measurement. The software now waits for the sample to start feeding.

9. Select the Air flow radio button. The vacuum unit will automatically come on and then, after a five second wait, the air line will be turned on automatically.

10. Select the Feed radio button in the Dry sampler control dialogue. The sam-ple will start to move down the tray. The software will only make a measure-ment when the measured obscuration is between the set obscuration limits.

Once the measurement is complete, the results will be saved to a measurement file.


Chapter 4 Making a measurement


To make a basic SOP measurement:1. Open the lid to the sample area and adding the sample to the sample tray. Close

and lock the lid.

2. Select Measure-Start SOP. A dialogue appears asking you to select an SOP. Select an SOP and press the Open button. The measurement is automatically made.

Page 4-4 MAN 0386


Part 2 - Appendices

A


Specification

Specification

Dispersion type Dry, with controllable airflow, controllable feed rate, and interchangeable feed trays automatically sensed by the system.

Typical applications Dry powders, pharmaceutical excipients, fillers, cements, flour, powder coatings.

Modes of operation Automatic via SOPs.

Manual via computer operating dialogues.

Weight 21.3kg.

Dimensions Width: 352mm

Height: 332mm

Depth: 355mm

Power 100-120V / 200-240 V AC, 50/60Hz, 240VA.

Maximum particle size

2000 microns, depending on particle shape and density.

Scirocco 2000 Page A-1

Appendix A SpecificationA


Page A-2 MAN 0386

B


Chemical compatibility

IntroductionThe Scirocco 2000 is manufactured from materials that are considered to give the widest protection from chemical attack. However, it is important to check that any sample you may use is chemically compatible with the materials that they will come into contact with within the dispersion unit.

This appendix lists all materials that come into contact with the sample in the nor-mal operation of the dispersion unit.

Components in contact with sample

Component Materials

Tray & venturi 316 stainless steel and ceramic

Sieve and ball bearings 316 stainless steel

Sample pipes to cell Tygon™

Cell Glass, 316 stainless steel

Vacuum hose PVC

Cell elbow 316 stainless steel

Vacuum retaining pipe 316 stainless steel

Scirocco 2000 Page B-1

Appendix B Chemical compatibilityB


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C


Regulatory statements

This appendix presents regulatory information.

Scirocco 2000 Page C-1

Appendix C Regulatory statementsC


CE Declaration of ConformityThe CE badge on this product, shown below, signifies conformance to European Commission Directives.

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Page C-2 MAN 0386

Index


A

Advanced - Measurement dialogue 3-11, 4-3Air cell

details 2-8overview 2-4

Air flow radio button 4-3Air in connector 2-8Air pressure

control 3-8faults 3-4guidelines 4-1optimum 3-8setting 4-2software control 3-2

Airflow mode 3-3Autostart 3-12

C

CE Declaration C-2Cell holder 2-10Cell shroud 2-9Cell windows

cleaning 2-8function 2-9

Chemical compatibility B-1Cleaning required check box 3-10Cleaning sequence 3-10Communications cable 2-7Concentration

importance of 4-2optimising 3-8

Controlling the accessorymanually 3-2

D

Dispersion unitschaining 2-7

Dry Accessory dialogue 3-2Dry powder guidelines 4-1

E

Earth lead 2-10Error indicators 3-4Exhaust connector 2-10

F

Features overview 2-2, 2-3Feed mode 3-4Feed rate

changing 4-2control 3-8software control 3-3

G

Gates (sample tray) 2-6

H

Help 1-3Hopper

cascade assembly 2-12sample funnel 2-12vibration rate 2-12

Hopper feed ratepurpose 3-9software control 3-5

Hopper instrumentsdefinition 1-3overview 2-12vacuum switcher box 2-13

L

Locking handle 2-9

M

Mains power supply 2-7, 2-11Making a measurement 3-1Manual control 3-2Manual measurement

procedure 4-2Measurement Cycles tab 3-10

Scirocco 2000 Page i

Index Scirocco 2000


Measurement displaywhen appears 4-2

Measurement guidelines 4-1Measurement snaps 3-12Measurements

manual and SOP 3-1, 4-2Menu commands 1-3Micro volume tray 2-5Model number 1-1Modes

Standby, Airflow and Feed 3-3Multiple accessories 2-7

N

Noise protection box 2-9

O

Obscurationin Measurement Display 3-8to control measurement 3-11

Obscuration filtering 3-12Obscuration limits 3-11Obscuration triggering 4-2Operator functions 1-2

P

Particle size (maximum) A-1Power requirement A-1

R

Rear paneldetails 2-7overview 2-4

Regulatory statements C-1

S

Sample area lid 2-4Sample concentration 3-8Sample exit port 2-4

Sample tray(hopper instruments) 2-13faults 3-4function 2-5indicator 3-5micro volume tray 2-5overview 2-2selection 3-8small volume tray 2-6

Sample tray areadetails 2-5overview 2-4

Sample tray lidinterlock 4-2

Sampler Selection tab 3-6Sampler Settings tab 3-7Sieve

function 2-6Small volume tray 2-6Software features 3-1SOP control 3-6SOP measurement procedure 4-4Specification A-1Standby mode 3-3Status indicator 2-4Supervisor functions 1-2

V

Vacuumfaults 3-4second unit (hopper instruments) 2-12, 3-10

Vacuum monitor connector 2-8, 2-10Vacuum switcher box

connector 2-7details 2-11fuse 2-11overview 2-5

Vibrator faults 3-4

Page ii Scirocco 2000

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