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Printed in England
MAN0389-1.0 Hydro 2000uP.book Page i Friday, March 16, 2007 4:11 PM
This manual describes the operation of the Micro Precision Hydro 2000µP sample
dispersion unit, one of the following:
InstrumentModel number
Hydro 2000µP (with ultrasonics)AWA2003
Hydro 2000µP (without ultrasonics)AWA2004
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
read this manual fully before starting the first measurement.
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 cannot be overstated so we recommend reading the chapter on sample preparation
(Chapter 8 of the main User Manual) as a priority.
Access to the dispersion unit
Within 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 personnel
Malvern 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.
Supervisor
The supervisor is the person responsible for the management/safety of the dispersion 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.
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.
Operator
An 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.
Warning!
Failure to follow this guideline could result in exposure to hazardous
voltages.
The Mastersizer 2000 optical bench is referred to as “the optical bench” or “the
instrument”.
The Hydro 2000µP is referred to in full 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”.
Menu commands
Menu 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 help
Full details on where and how to obtain help can be found in Chapter 1 of the
Mastersizer 2000 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
This chapter gives a simple overview of the dispersion unit. All key aspects of the
dispersion unit’s operation are explained in very simple terms. This chapter covers:
The sole purpose of any sample dispersion unit is to prepare the sample then
deliver it to the measurement zone of the optical bench so that it can be measured.
The Hydro 2000µP allows the Mastersizer to be used for particle-in-liquid particle
sizing and has been specifically designed so that only small amounts of sample and
suspending liquids (dispersants) are required.
The small volume of the Hydro 2000µP is ideal when using solvent dispersants or
when samples and dispersants are either expensive or hazardous.
The materials used in the manufacture of the dispersion unit maximise the range of
samples which can be measured.
Other features of the dispersion unit include:
Variable speed pump – allows a wide range of particle sizes and densities to
be suspended and circulated.
Ultrasonic system (optional) – allows particle agglomerates to be dispersed
and assists in removing bubbles from the system.
Warning!
When using solvents, especially those with low ignition points, minimise
the use of ultrasonics. There is a remote possibility that localised heating
caused by the ultrasonic action may cause an explosive reaction. Check the
Material Safety Data Sheets for all substances used.
Temperature sensing – an internal sensor monitors the temperature of the
dispersant. The software can be configured so that measurements are only
made between user specified temperature limits. This can be used to ensure
that the instrument can only be used when it has reached the correct temperature.
How the dispersion unit is controlled
The dispersion unit is controlled using a single software dialogue with sliders for
the pump speed and ultrasonic power (Chapter 3 has details). The dialogue also
has pump pause, drain valve and Anaerobic fill buttons.
When controlled through a Standard Operating Procedure (SOP), the software
tells the user what value to set for each parameter.
The control unit which contains most of the control electronics.
The cell unit which contains the cell, the sample well, pump, ultrasonic probe
(optional) and the drain facilities.
The dispersant is injected into the cell via the dispersant inlet port using a syringe
. Once preliminary measurements (“backgrounds”) are made, the sample to be
measured is added to the well
. The pump agitates the dispersant to ensure that
the sample does not settle out and continually circulates the sample through the
cell
and then back to the well.
Within the cell, the dispersant and sample flow between two glass windows
windows are precisely mounted within the measurement zone of the optical bench
where a laser
within the sample scatter the laser light. This scattered laser light is measured by
the optical bench and used to calculate the particle size distribution of the sample.
Hydro 2000µPPage 2-3
. The
is passed through the sample/dispersant mixture. The particles
The optional ultrasonic probe can be used to break up particle agglomerates and
help to remove bubbles from the system.
Once the sample has been measured, an internal drain valve is operated and the dispersant and sample are drained to an external beaker
.
The lid for the well
should always be fitted during a measurement. The lid is
locked in place by rotating the locking lever
All functions of the dispersion unit are controlled using the Malvern software.
Hardware features
This section describes the hardware in detail.
Main system components
The diagram below shows a typical installation for the Hydro 2000µP. Its main
components are identified. These components are examined in more detail later in
this section.
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5
ill 5407
Power supply
The external DC Power Supply Unit (PSU) supplies all power requirements to the
dispersion unit.
The PSU used on the Hydro 2000µP is not designed for operation in wet
conditions. Do not place it in areas that are prone to spillages.
Warning!
Only use the power supply and cables supplied by Malvern Instruments.
Control unit
The control unit contains most of the control electronics for the dispersion unit.
Power and communications cables are connected to the control unit. A control
cable is connected from the front of the control unit to the front of the cell unit.
Cell unit
The cell unit contains the cell, well, pump and drain facilities. The cell unit is
designed to circulate the sample and dispersant mixture and pass it through the
analysing laser beam of the optical bench.
Sample well
The well in the cell unit is where sample to be measured is added. The sample well
and connecting pipes have a capacity of less than 20ml.
Dispersant input/syringe
The dispersant for suspending the sample and flushing the system is injected into
this port using a syringe. Always use a syringe with a maximum capacity of 20 to
25ml.
Drain beaker
Once the measurement is complete (or during a flush routine to clean the system)
an internal drain valve can be operated. The contents of the cell will drain through
the drain port into the drain beaker.
If the end of the drain pipe is under the surface of the waste liquid, the back pressure created may prevent the cell from draining correctly. Typically ensure that the
end of the tube is approximately 3cm below the rim of the beaker (slide the beaker
holder until the correct length is achieved).
If using hazardous dispersants or samples, do not allow the beaker to
become over-full. If dispersants or samples are noxious, the instrument
should ideally be used in a fume cupboard.
ill 5643
Drain beaker holder
The drain beaker may hold hazardous samples and dispersants. The drain beaker
holder secures the drain beaker to prevent it from being accidentally knocked over
when the cell unit is removed from the optical bench.
We recommend that the beaker holder is always used.
Cell unit holder
The cell unit holder is a “parking” area for the cell when it is not in use. This is particularly useful when more than one dispersion unit is in use. It allows the cell to be
removed and stored without the need to disconnect it from the dispersion unit.
When the cell is “parked” for a short period make sure that the cell is full of dispersant. If it is to be parked for longer periods, the unit should be drained and the cell
windows dried. The Essentials manual describes these procedures.
Well lid
The well lid is used to reduce the escape of hazardous fumes when measuring
using hazardous samples and dispersants. It also reduces the risk of accidental
splashing from the well.
Always use the well lid when making measurements or moving the cell unit.
Always lock the lid into place with the lid locking lever
.
Lid locking lever
The lid locking lever is used to lock the well lid in place when measurements are
taking place.
The dispersant valve is used to prevent sample or dispersant leaking when the dispersant input syringe is removed.
Two types of valve are available:
Aqueous valve – this is disposable and can be used with non aggressive dis-
persants such as water. The valve is easily identifiable as it is made of transparent, purple plastic.
Non-aqueous valve – suitable for use with a large range of chemically aggres-
sive dispersants. The non-aqueous valve is white and has a tap on its side.
Replacement valves are available from a Malvern representative.
Controller unit
This section examines the controller unit in more detail. As stated above, the controller unit contains most of the control electronics for the dispersion unit.
Rear panel
The rear panel of the controller unit is shown below and its main features identified.
DRAIN OPEN/CLOSED
CAUTION
Flash tests can
permanently damage
this equipment
WARNING :
To prevent electric shock do not remove screws.
No user s erviceabl e parts ins ide.
Refer servicing to Malvern trained service personnel.
The PSU is not designed for operation in wet conditions. Do not place it
in areas prone to spillages.
Warning!
Only use the PSU and cables supplied by Malvern Instruments.
Accessory comms “in” connector
The communications cable from the optical bench or from another dispersion unit
connects here.
Accessory comms “out” connector
If more than one dispersion unit is connected to the system and this is the first dispersion unit in line, a communication cable will be connected from this connector
to the Accessory comms - in connector on the second dispersion unit.
Caution!
The termination plug supplied with the optical bench must be fitted here
if this is the only dispersion unit connected or it is the last dispersion unit
in the line.
Manual drain
The manual drain button can be pressed to drain the well. Users may wish to do
this if, for example, they need to drain the dispersion unit without having to start
the control software. Pressing the button once (for about half a second) will open
the drain valve. Pressing the button a second time will close the drain valve. If the
drain valve is left open for more than 15 minutes it will automatically close.
If the ultrasonic option is fitted, this cable will carry power and control signals for
the ultrasonic probe between the control unit and the cell unit.
Warning!
The Ultrasonic control cable carries high voltages. Under normal operating procedures this is perfectly safe.
Inspect the cable at regular intervals for any sign of damage. Never operate
the equipment if the cable is damaged.
Cell unit
The cell unit is shown below with its main features identified.
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Well cone
The well cone is where the sample is added to the cell unit. Typically, dispersant is
added by filling the well to within 1 to 2mm of the top of the well. Perform an
anaerobic fill (to remove bubbles) and then remove dispersant directly from the
well using a pipette so that the well is about a quarter full.
Overflow
If the well is overfilled any excess is directed to the drain port via the overflow.
Control cable
The control cable carries all power and communication signals between the control
unit and the cell unit (with the exception of ultrasonics).
Ultrasonic control cable (optional)
If the ultrasonic option is fitted this cable carries control signals for the ultrasonic
transducer between the control unit and the cell unit.
Dispersant inlet port
The dispersant for suspending the sample and flushing the system is injected into
this port using a syringe. To avoid introducing bubbles into the system, use a slow,
steady pressure when injecting the dispersant; see Chapter 2 for details.
Warning!
Always consult the Materials Safety Data Sheet for any handling and
safety information for all dispersants used.
Only use syringes with a maximum capacity of 20-25ml.
The dispersant for suspending the sample and flushing the system is injected into
this port using a syringe. To avoid introducing bubbles into the system, use a slow,
steady pressure when injecting the dispersant; see Chapter 2 for details.
Fill the well until dispersant is visible within the well cone.
Dispersant valve
The dispersant valve must be used on the dispersant inlet to prevent sample/dispersant from leaking when the dispersant syringe is removed.
Two types of valve are available, as described earlier. Replacement valves are available from a Malvern representative.
Drain port
When the drain valve is operated, the contents of the cell will flow out through this
port. A tube will guide the contents to a waste beaker. Always ensure that the waste
beaker has enough capacity before draining the cell.
Well lid
The well lid should always be in place when making measurements (except when
adding sample). The lid reduces the amount of vapour released when using solvents as a dispersant. It also stops dispersant from welling up and stops air being
sucked in.
Additionally, when measurements are performed using solvents, users may occasionally find that the background levels are very high. This is due to temperature
gradients within the solvent. The normal cure is to wait for several minutes for
thermal equilibration, or even to warm the solvent beforehand. In many cases, a
much simpler and quicker solution is to ensure that the lid is in place.
Lid locking lever
The lid locking lever is used to lock the well lid into place during measurements.
Cell windows
The 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 cleaning or replacement.
Caution!
The cell windows are delicate and should be treated with caution; refer to
the Essentials Manual for details on cleaning the windows.
Window ring lock screws
The windows can be removed for cleaning. The window ring lock screws can be
loosened to allow the window ring and window to be removed; refer to the Essen-tials Manual for details.
The dispersion unit can either be controlled manually or automatically by running
a Standard Operating Procedure (SOP). Making a measurement is fully documented in Chapter 4 of the main User manual.
The system automatically detects which dispersion unit and cell is connected. If
more than one dispersion unit is connected, the system detects all dispersion units
connected, but only the dispersion unit that has its cell installed on the optical
bench will be “active”.
Manually controlling the dispersion unit
To control the dispersion unit manually either select Configure-Accessory or,
when making a manual measurement, click the Accessory button in the Meas-urement Display window. This accessory control dialogue appears:
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1
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2
4
3
6
This dialogue is specific to the Hydro 2000µP. It has separate Control and Errors
tabs. Use it to alter the pump speed and (optionally) the ultrasonic power by moving the relevant slider bar.
The speed of the pump (which controls the speed at which the sample is circulated) is altered by moving the slider. Use the up and down arrows under the slider
for fine adjustment of the pump speed.
Ultrasound control (optional)
Warning!
When using solvents, especially those with low ignition points, minimise
the use of ultrasonics. There is a remote possibility that localised heating
caused by the ultrasonic action may cause an explosive reaction. Check the
Material Safety Data Sheets for all substances used.
The power of the ultrasonic probe is altered by moving the slider. Use the up and
down arrows under the slider for fine adjustment of the ultrasonic power.
Dispersant temperature
The temperature of the dispersant within the cell is continually monitored and displayed here. Temperature monitoring can be used in conjunction with the Sam-pler Settings dialogue to limit the range of temperatures at which measurements
can be made.
Pause Pump button
Pressing the Pause Pump button stops the pump motor. Pressing the button a
second time restarts the pump. The indicator to the right of the button shows red if
the pump is paused, and green when the pump is running.
Note
If having difficulty with bubbles in the system, they can often be removed
by turning the pump on and off in quick succession using Pause Pump.
Drain Valve button
Pressing the Drain Valve button will open the drain valve, allowing the contents
of the cell to be emptied into the waste beaker. The indicator to the right of the
button will show red if the drain is open and green when the drain is closed.
Anaerobic fill button
Due to the small volume of the Hydro 2000µP and associated problems of removing bubbles from the system, a special fill sequence called Anaerobic fill can be
used. Chapter 4 gives details.
The following indicators on the Errors tab illuminate if an error condition has
been detected.
Connection box disconnected – shows red if the control cable from the
control unit to the cell unit is not connected.
Dispersant Temperature Probe – shows red if the temperature is outside
the range 10°C - 35°C or there is an internal error with the temperature sensor.
Contact a Malvern representative if this error condition persists.
Drain Valve – illuminates if the drain valve has failed to drive (i.e. it has stuck
open or closed). This may be caused by leaving a sample in the cell for long
periods - this may have set and bonded the drain valve. Never leave the sample
in the cell for long periods - always flush the cell with clean dispersant. Contact
a Malvern representative if this error indicator illuminates.
Pump – illuminates if there is a problem with the pump controller electronics
Pump over temperature – illuminates if the pump is over its operating tem-
perature range. The pump will stop until its temperature returns to the operating range. The pump will typically overheat if the sample dispersant is too
viscous or the sample material is too large, causing jamming.
Pump speed control – illuminates if the difference between the speed
demanded and the actual speed exceeds 500rpm for over 10 seconds.
Ultrasound – illuminates if there is an error with the ultrasound control elec-
tronics.
Ultrasound displacement – illuminates if the current supplied to drive the
ultrasound probe is too high.
Ultrasound timeout – illuminates if the ultrasound is left on for over 15
minutes.
Status indicators
These indicators give the current status of the pump and ultrasonic probe. If this
indicator shows green then the pump or ultrasonic probe are currently in use. If the
Ultrasonics indicator is greyed out then the unit does not have the ultrasonic
option installed.
A Standard Operating Procedure (SOP) can be configured to control all settings for
the dispersion unit automatically. When an SOP is run the software (depending on
how the SOP is set up) automatically runs a measurement, giving instructions to
the operator such as when to add dispersant, sample, etc. The SOP even reports if
the wrong cell unit is fitted.
The SOP wizard is described in full in the main User Manual. Here we just
describe those dialogues which are specific to the Hydro 2000µP. These are the
Sampler Selection and Sampler Settings dialogues.
Sampler Selection dialogue
The Sampler Selection dialogue is shown below:
It features:
Sample handling unit list
Select the dispersion unit to be used from the drop down list
. All dispersion
units available will be listed, even those that are not attached to the system. This
allows an SOP to be written remotely from the system.
All systems the SOP is distributed to must have the dispersion unit connected.
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ill 7774
The system allows up to two of each dispersion unit to be connected to the optical
bench. In this situation, the dispersion units will be identified as unit A and B - in
the case of this dispersion unit there would be an entry for Hydro 2000µP (A) and
Hydro 2000µP (B). If using just one dispersion unit, select the “A” option.
Sample handling unit options
This dispersion unit is supplied in two versions, with ultrasonics and without ultrasonics. Use this pull down list to select the model in use.
If the user tries to run an SOP that has been defined for an dispersion unit with
ultrasonics on an dispersion unit without that option, a message is displayed, telling
them to connect the correct dispersion unit.
Sampler Settings dialogue
The Sampler Settings dialogue is shown below:
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ill 7775
Its features are:
Pump speed
The pump speed is altered by moving the slider or entering the required speed in
the RPM box to the right of the slider.
Selecting the Advanced button displays the Vari-flow options. Some materials
such as metal flakes have been found to form structures when they are circulated
through the cell at normal pump speeds. These structures give rise to a secondary
diffraction pattern that is incorrectly interpreted as a small peak at 1000 microns.
Vari-flow allows these materials to be dispersed in the well in the normal way and
then the pump is briefly turned off or reduced before measurement of the sample.
When the pump is turned off, the structures in the sample are randomised and the
measurement can be made without the occurrence of the secondary diffraction pattern.
When the flake material is suspended in a volatile solvent, such as white spirit, variflow is even more useful since it assists the rapid thermal stabilisation of the optics.
When the sample well is filled with fresh solvent, very high backgrounds can often
be observed. These arise from thermal gradients in the solvent causing steering of
the laser beam onto the inner rings of the internal detector. As the temperature
equilibrates, the background will fall to normal levels (80-100) and the measurement can proceed. Pausing the pump after the solvent has had a chance to thoroughly disperse through the system will accelerate the fall of the background to
normal levels.
Ultrasonics
Warning!
When using solvents, especially those with low ignition points, minimise
the use of ultrasonics. There is a remote possibility that localised heating
caused by the ultrasonic action may cause an explosive reaction. Check the
Material Safety Data Sheets for all substances used.
The ultrasonics radio buttons enable the ultrasonic transducer. The options are:
None – no ultrasound.
Continuous (from sample addition) – ultrasound is activated after sample
is added and will run continuously.
Pre-measurement – ultrasound is activated for a set time prior to measure-
ment. For pre-measurement mode, type in the required duration in seconds in
the Duration box.
Continuous (from start) – ultrasound is active throughout the measure-
ment. Ultrasound will start after the electrical background is complete. The
stabilising period will add a delay between the electrical background and the
optical alignment. During this delay ultrasound will be active to allow bubbles
to be driven from the dispersant.
Either click and drag the slider bar to set the level, or type the exact level required in
the box to the right of the slider bar.
Determine the optimum ultrasound level and duration using manual control,
ensuring that the lowest setting giving satisfactory dispersion is obtained. Record
the settings and transfer these to the SOP in the Sampler Settings dialogue using
the slider controls.
A pre-measurement delay can be added before the measurement to allow thermal
equilibration to occur after ultrasound has been applied. If this is not done the analysis may show the presence of large particles which are not in the sample. This is
caused by the refractive index differences observed in the sample cell when the dispersant is not equilibrated. Choose a delay sufficiently long enough for adequate
thermal equilibration to occur.
To set the delay, highlight either the minutes or seconds in the entry box, then use
the selection arrows to alter the time; alternatively the time can be typed in. A delay
of between 0 and 59.59 minutes can be chosen.
Temperature Monitoring
It is possible to monitor the temperature of the sample and dispersant and to set the
software to only make measurements between specified limits.
Temperature monitoring is enabled by selecting the Allow measurements only…. check box.
The options are:
Lower/upper limit – this section specifies the temperature range within
which the sample/dispersant must be for the measurement to start. This limit
must be in the range of 10° to 35°C.
Stabilising temperature – the time for which the temperature must be stable
before the measurement proceeds.
Time-out period – the measurement will be abandoned if the temperature is
The Hydro 2000µP uses very low volumes (approximately 20ml) of dispersant and
sample. When using such small quantities, take the following precautions when
making a measurement:
Minimise the amount of sample lost during sample preparation, or through
sample adhering to the sides of the well.
Cleanliness of the system is critical: very small amounts of cross-contamination
can bias the results.
Manage the pump speed to prevent the introduction of bubbles, while also
ensuring that the sample is kept in suspension. This is true for all wet sample
dispersion units but particularly important with the small dispersant volumes
of the Hydro 2000µP.
The basic procedure
Add dispersant to the well by injecting the requested dispersant through the inlet
port. Inject the dispersant slowly until the level of the dispersant is within 1 to
2mm of the internal rim of the well.
Because the stirring and the circulation of the sample is carried out in the chamber
below the well cone, keep the level of dispersant in the well low. If sample is seen
adhering to the sides of the well cone, use a pipette to withdraw some of the dispersant from the well to rinse the sides of the well. Once the sample has been added, it
is important to replace the well lid and lock it in place using the locking lever.
Minimising sample loss
Sample loss by adhesion
To prevent sample adhering to the side of the sample well during sample addition,
it is typical to have the dispersant at a level a quarter of the way up the well. This
allows the sample to be taken into the well cavity by the dispersant.
A typical procedure is:
1.Fill the well to 1-2mm below the top of the well.
2.Run an anaerobic fill sequence (press the Anaerobic fill button on the acces-
sory control dialogue).
3.Once complete, use a pipette to remove dispersant so that the well is about a
Choose a sample preparation method that ensures that all particles are transferred
to the well. A recommended method is to prepare a slurry in a small container and
add this to the well using a pipette. Add as a maximum 2ml of sample volume, but
1ml is preferred.
Material will usually be seen collecting in the bottom of the container.
To take a representative sample of the material:
1.Make the slurry more dilute than is normal for larger volume sample disper-
sion units. This will ensure that adding slurry does not lead to an excessive
concentration.
2.Tilt the container at an angle.
3.Agitate the dispersant by continually filling and discharging the pipette to
ensure the material is suspended in the dispersant (rather than sinking to the
bottom).
4.Once dispersed, finally fill the pipette with as much of the dispersant as possi-
ble and transfer it to the well drop by drop, pausing between drops to allow the
sample to fully disperse i.e. monitor the obscuration value until it stabilises.
5.When adding the sample, ensure that it is added directly to the dispersant
rather than trickling it down the sides of the well walls. This prevents sample
loss through adhesion.
Cleanliness
Cleanliness is essential; since only 10-50mg of sample is added, it only takes a small
amount of cross-contamination from a previous measurement to bias results significantly. Consider the following points when making measurements:
When cleaning, rinse the system three or four times. It doesn’t use much dis-
persant, and gives better performance for the next sample.
The first rinse of a clean is sometimes best done by injecting 5-10ml bursts of
dispersant into the well while the pump is running and the drain valve open.
This tends to rinse larger particles through the system.
When changing dispersants, blow each dispersant out of the fill tube with a
syringe full of air (with the drain open) to reduce cross contamination.
When changing over from an oily organic solvent (vegetable oil, etc.) to water,
use a biological drain cleaner (containing food enzymes) to clean out the last
traces of oil.
Control the pump speed to prevent the introduction of bubbles while ensuring that
the sample is kept in suspension. This is true for all wet dispersion units but particularly important with the small dispersant volumes of the Hydro 2000µP. The
Mastersizer sees bubbles as particles and measures these. Bubbles will vary in size
but are typically in the region of 100 microns. In many cases bubbles can be clearly
seen as a separate peak when the measurement data is analysed.
Consider the following points when making measurements:
When filling the system with dispersant, turn off the pump to prevent it intro-
ducing bubbles.
Fill the system with dispersant slowly to avoid trapping bubbles.
When the system is first filled, bring the pump speed up slowly to clear any
remaining bubbles, without breaking them into smaller ones. Ideally use the
Anaerobic fill sequence (described later) to remove air and bubbles from the
system.
Take care with the pump speed. The system is designed, and balanced, for
water. Other dispersants may tend to well up in the well or pump chamber as
the pump speed increases. Full speed (5000 rpm) is too much for most dispersants, so do not use 100% pump by default. See the table in the Anaerobic fill
section later for examples of settings.
Choose a pump speed high enough to keep the particles in suspension. Using
too high a pump speed will tend to draw air into the system.
Always fit the well lid during measurements.
Finally, on the last wash before filling the system to make a measurement, we
recommend that the pump is set to off whilst draining. This is because the
action of running the pump whilst draining can cause the formation of small
air bubbles in drops of dispersant that may remain in the system after draining.
If the system is then filled immediately in order to perform a measurement,
these air bubbles are circulated and sized in addition to the required sample.
Before starting a measurement, ensure that the correct cell unit is installed in the
cell area and then power up the system. The stages are outlined below.
Powering up
Power up the system by:
Switching on the dispersion unit(s).
Switching on the optical bench.
Switching on the computer and starting the software by double-clicking on the
Mastersizer 2000 icon.
Filling the cell with clean dispersant
Before a measurement fill the cell with clean, degassed dispersant (when the measurement is run the software asks if this has been done). Take care not to let air
(either dissolved gasses or bubbles) into the system. The following procedure is
recommended to fill the cell unit.
Degassing the dispersant
Gases dissolved in the dispersant can form bubbles in the cell. To prevent this from
happening, we recommend that the dispersant is degassed prior to adding it to the
cell unit. The following procedure is suggested if water is used as a dispersant.
Warning!
This procedure may not be suitable for all dispersants, especially dispersants with low boiling/ignition points.
To de g a s w a t er :
1.Choose a vessel that has a lid and fill the vessel with water. Do not fill the vessel
completely at this point.
2.Loosely fit the lid, but do not tighten it. This ensures that pressure does not
build up in the vessel, while preventing dust getting in.
3.Place the open vessel in an ultrasonic bath that can be heated.
4.Set the ultrasonic power to 60W and the water bath to 70°C.
6.Once the water has been degassed, a number of bubbles may have formed on
the inside surface of the vessel. To remove these, fit the lid to the vessel and
very carefully turn the vessel on its side (see the diagram below). Slowly rotate
the bottle through one complete revolution - the bubbles will be removed as
they meet the air/fluid interface.
Vessel
Heater
Ultrasonic bath
ill 5638
Filling the syringe
Take care to avoid air entering the syringe when filling it with dispersant.
Page 4-6MAN 0389
Bubbles
ill 5639
Warning!
Avoid using a syringe with a capacity of more than 20ml. The additional
capacity may cause the cell to overflow, causing hazardous conditions
within the cell unit.
1.Insert the syringe into the vessel of dispersant.
2.Draw back the syringe very slowly. Pulling back too quickly will cause “boil-
ing” on the surface of the syringe plunger (see the diagram below) or air may
be dragged back through the syringe seal.
Syringe
Syringe plunger
“Boiling”
Syringe body
ill 5640
3.Hold the syringe with the tip pointing upwards, and push the plunger in to dis-
place any air (as shown below). It may be necessary to tap the body of the
syringe to displace any air bubbles.
i
Hydro 2000µPPage 4-7
ill 5641
Note
Avoid having to refill the syringe half way through filling the cell, as disconnecting and reconnecting the syringe may introduce air into the cell.
When filling the standard 20ml syringe, fully draw back the plunger to take
up enough dispersant to fill the cell (its approximate capacity is 18ml).
1.Connect the syringe to the valve attached to the front of the cell unit.
2.Hold the syringe with the plunger facing upwards (as shown below) so that any
bubbles in the syringe rise to the top and are not injected into the cell.
Valve
Pipe to cell unit
3.Filling the cell now depends on which of the two types of dispersant valve
being used:
For the non-aqueous valve (suitable for use with a large range of chemi-
cally aggressive dispersants) open the tap on the side of the valve. Slowly
press the plunger of the syringe (typically over about a 20 second period).
Fill the cell until the sample well is almost full (to within 1 or 2mm of the
internal well rim. Once full, close the tap on the side of the valve. Note
that there is no need to remove the syringe from the valve.
The aqueous valve (used with non aggressive dispersants such as water)
does not have a tap to control the flow through the valve but acts as a nonreturn valve. To fill the cell, slowly press the plunger of the syringe (typically over about 20 seconds). Fill the cell until the sample well is almost
full (to within 1 or 2mm of the internal well rim).
Note
For the valve to function correctly as a non-return valve, the syringe must
Due to the small volume of the Hydro 2000µP and associated problems of removing bubbles from the system, a special fill sequence called Anaerobic fill can be
used. During an anaerobic fill the pump speed is increased in steps to a target speed.
A short pause is added between steps to allow bubbles to disperse.
To use anaerobic fill click the Anaerobic fill button on the accessory control dialogue’s Control tab. The Anaerobic fill dialogue will appear. This contains a field
for setting the final pump speed. This is the speed the pump will run at after the fill
process has finished. During a manual measurement the last value used will be
recalled. During an SOP this will be the pump speed specified in the SOP.
For best results set the pump speed field 500rpm above the final speed required.
Once the Anaerobic fill sequence is complete the final pump speed can be reset.
Example values are given below.
MaterialPump speed (SOP)Anaerobic fill
Glass Beads in:
Water
Oils
Alcohols
Latex in water2000rpm2500rpm
2500rpm
3000rpm
2500rpm
3000rpm
3500rpm
3000rpm
The dialogue prompts the user to fill the well. Once it’s full press the Go button.
As bubbles escape the level of the dispersant may drop.
Once complete, ensure that the well is approximately a quarter full, using a pipette
to remove excess dispersant if necessary.
The above procedures are ideal if the SOP is set up or all the parameters for a manual measurement have been specified. Users measuring a new material must either
create or modify an SOP or set up the options for a new manual measurement.
This section outlines the setup for measuring a new sample.
Measuring new samples - manual measurement
The basic procedure is the same as outlined above. When the user selects the
Options button in the measurement display, the Measurement Options dialogue appears. This dialogue controls all aspects of the measurement.
Use the Materials tab to select a different material and dispersant or define the
optical properties of the new material. This tab also allows users to specify
options regarding the result calculation.
Note
If a material is created or modified the computer calculates a new scattering
i
model. This usually takes between one and 10 minutes, depending on the
power of the computer. However, if the ratio of the refractive index of the
sample to the dispersant is in the range 0.99 to 1.01, then this time may
substantially increase. Under these conditions we recommend that the
model is generated overnight.
Use the Measurement tab to set up measurement times, set measurement
alarms, etc.
Press the Document button in the Measurement display to open the Document
dialogue. Add relevant details that will allow a user to reproduce the measurement
at a later date.
All the options available are basically the same when setting up an SOP. For more
details of these options see Chapter 4 of the main User Manual.
Measuring new samples - SOP measurements
Creating an SOP is easy. Select Configure-New SOP; the software will run
through an SOP Wizard. This wizard asks a series of questions, such as:
what are the optical properties of the sample?
what is it suspended in?
how fast should the pump be?
how much ultrasonic dispersion is required?
do any additives need to be added to the sample to aid dispersion?
These are all the questions that need to be answered in order to define a measurement.
Anyone can create an SOP but typically it is the responsibility of the system administrator. An SOP can be created by a specialist and then distributed to all Mastersizer 2000 users in an organisation.
Remember that no instrument needs to be connected to the software to write an
SOP. The Malvern software can be installed on a remote computer and SOPs created and edited before they are tried out on an instrument. (The Essentials Man-ual has details on installing the software on another computer.)
A completely new SOP can be created by selecting Configure-New SOP and following the SOP Wizard. An existing SOP can be easily edited either to correct it
or to create a new SOP based on it. If several slightly varying SOPs are being saved,
it is useful to include the differentiating features in the SOP name e.g. “glopalene
ultrasound 60”, “glopalene ultrasound 40”.
To edit an SOP select Configure-Existing SOP…. A tabbed dialogue will appear.
Each tab corresponds to a screen from the SOP Wizard. Select a tab and change
any of the entries as required. Click OK to save the changes.
To create a new SOP based on an existing one, first modify the existing SOP using
Configure-Existing SOP. Once all the changes have been made, the Save-As
dialogue will appear. Save the SOP under a different name.
The Essentials Manual covers most maintenance procedures. This chapter
describes one non-essential procedure, how to move the cell holder from its position on the right of the optical bench, should this be necessary.
The Hydro 2000µP is typically configured to be positioned on the right of the optical bench
optical bench
the control unit.
. For users who wish to locate the dispersion unit on the left of the
we recommend that the cell holder be swapped to the other side of
The Hydro 2000µP is manufactured from materials that give the widest protection
from chemical attack. However, it is important to check that any sample or dispersant used is chemically compatible with the materials it will come into contact with
in the dispersion unit.
This appendix lists all materials that come into contact with the sample and dispersant during normal operation.
The CE badge on this product, shown below, signifies conformance to European
Commission Directives.
Page C-2MAN 0389
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MAN0389-1.0 Hydro 2000uP.book Page i Friday, March 16, 2007 4:11 PM
Index
A
Accessory comms in connector
2-8
Accessory comms out connector 2-8
Accessory control dialogue 3-2
Anaerobic fill 3-4, 4-9
Anaerobic fill dialogue 4-9
Anaerobic fill sequence 4-4
Aqueous valve 2-7, 4-8
B
Background measurements
2-3
Bubbles 4-4
C
CE Declaration
C-2
Cell
filling
4-8
Cell unit
details
2-10
function 2-3, 2-5
Cell unit holder 2-6
Cell windows 2-3, 2-12
Changing dispersants 4-3
Chemical compatibility B-1
Cleanliness
guidelines
4-3
Cleanliness critical 4-2
Control cable 2-9, 2-11
Control unit 2-3, 2-5
Controller unit 2-7
Controlling the dispersion unit
manually
3-2
D
Degassing dispersant
4-5
Degassing water 4-5
Dimensions A-1
Dispersant
changing
4-3
degassing 4-5
overview 2-3
Dispersant inlet port 2-11
Dispersant input/syringe 2-5
Dispersant temperature 3-3
Dispersant valve
Filling the syringe 4-6
Front panel (controller unit) 2-9
G
Getting help
1-3
H
Hardware features
2-4
Hazardous dispersants/samples 2-6
I
Instrument preparation
4-5
L
Lid locking lever
2-6, 2-12
Low volume use 4-2
Lower/upper limit (temperature) 3-8
M
Main system components
2-4
Hydro 2000 µPPage i
MAN0389-1.0 Hydro 2000uP.book Page ii Friday, March 16, 2007 4:11 PM
Index Hydro 2000 µP
Making a measurement 3-2
Manual control 3-2
Manual drain 2-8
Measurements
guidelines
4-4
Menu commands 1-3
Model number 1-1
N
Non-aqueous valve
2-7, 4-8
O
Operator functions
1-2
Overflow 2-11
P
Particle size range
A-1
Pause pump 3-3
Power input 2-7
Power requirement A-1
Power supply 2-4
Power switch 2-9
Powering up 4-5
Preparing for measurement 4-5
Pump - what it does 2-3
Pump speed 2-2, 3-6, 4-4
Anaerobic fill 4-9
changing 2-2
Pump speed control 3-3
Pump speeds 4-4
R
Sample well 2-5
Sampler Selection dialogue 3-5
Sampler Settings dialogue 3-6
Scattered laser light 2-3
Slurry 4-3
SOP control 3-5
Specification A-1
Stabilising temperature 3-8
Status indicator 2-9
Status indicators 3-4
Supervisor functions 1-2
Swapping cell holder position 5-2
Syringe
capacity to use
4-6
filling 4-6
Syringe capacity 2-11
T
Temperature monitoring
3-8
Temperature sensing 2-2
Time-out period (temperature) 3-8
U
Ultrasonic control cable
2-10, 2-11
Ultrasonic power
changing
2-2
Ultrasonic probe 2-4
Ultrasonic system 2-2
Ultrasonics settings 3-7
Ultrasound