Milestone MAXI-44 User manual

MAXI-44 eT
User Manual
MA210
MILESTONE
HELPING
CHEMISTS

Milestone Srl MA210-002 –MAXI-44 eT –User Manual
GETTING STARTED GUIDE
1
Thank you for selecting our microwave system.
We are sure that you will be completely satisfied with the performance of
this new unit entering your laboratory. We invite you to read carefully this
user manual and to keep it in reach for convenient and fast consulting. The
person who will be using this unit should have received an appropriate
training from a Milestone trained technician. For any possible clarification
or any request for assistance please contact either our Representative in
your country:
or Milestone at the following address:
Milestone Srl
Via Fatebenefratelli, 1/5
24010 Sorisole (BG) Italy
Tel [phone]
Fax [phone]
Website www.milestonesrl.com
E-mail [e-mail]
Pubblication date (gg/mm/aaaa) 15/10/2021

Milestone Srl MA210-002 –MAXI-44 eT –User Manual
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1SAFETY INSTRUCTIONS......................................5
1.1 General Information.............................................................5
1.2 Safety in operations.............................................................5
1.3 Any unit manipulation allowed .............................................5
1.4 Maintenance and parts replacement....................................6
1.5 Customer support................................................................6
1.6 Other hints...........................................................................6
1.7 Working with accessories ....................................................6
2SYSTEM DESCRIPTION........................................7
2.1 Overview .............................................................................7
2.2 Configurations .....................................................................7
2.3 Technical Specifications......................................................7
2.4 Temperature control ............................................................8
3VESSEL SYSTEM ..................................................9
3.1 Operations with MAXI-44, high throughput rotor..................9
Weighing.......................................................................................................9
Chemicals addition......................................................................................10
3.2 Vessel construction MAXI 34 / 44......................................10
4OPERATIONS ......................................................11
4.1 Protection shield introduction.............................................11
4.2 Vessel closure and installation...........................................12
4.3 Rotor removal....................................................................14
4.4 Vessel removal..................................................................14
4.5 Vessel opening..................................................................15
5CARE AND MAINTENANCE INSTRUCTIONS....17
5.1 General cleaning ...............................................................17
5.2 Rotor movement................................................................17
5.3 Care and maintenance of IR (easyTEMP) sensor..............17

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Cleaning of IR (easyTEMP) sensors...........................................................17
5.4 EasyTEMP Calibration Test instructions............................18
eT Calibration Test procedure.....................................................................18
6CLEANING INSTRUCTIONS................................20
6.1 General..............................................................................20
6.2 Leaky cover.......................................................................20
6.3 Test of microwave absorption............................................20
6.4 Cleaning of the cover.........................................................21
6.5 Cleaning of protection shield..............................................21
6.6 Cleaning of PTFE vessel...................................................21
7APPENDIX............................................................22
7.1 Regular test (Accessories/vessels/rotors)..........................22
8MAXI-44 ROTOR TIPS AND TECHNIQUES........23
8.1 General working specifications..........................................23
Sample amount...........................................................................................23
Volumes......................................................................................................23
Temperature ...............................................................................................23
Pressure .....................................................................................................23
Acid solutions..............................................................................................23
8.2 MAXI-44 Vessels...............................................................23
Components................................................................................................23
Labeling......................................................................................................24
Usage Log ..................................................................................................24
8.3 Operating tips....................................................................24
Sample Weighing........................................................................................24
Acid addition and digestion temperature .....................................................25
Vessels closure / opening. ..........................................................................26
How to open the vessels (venting) ..............................................................28
Digestion of water/waste water samples (i.e. EPA3015A method) ..............28
Active cooling after every run......................................................................29
8.4 Cleaning............................................................................30
Clean and dry between runs .......................................................................30
Cleaning vessels and covers.......................................................................30
Cleaning vessels and covers.......................................................................30
Surface Cleaning ........................................................................................30

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Alternative Cleaning Procedures.................................................................31
Cleaning vessels and covers from NOx contamination................................32

Milestone Srl MA210-002 –MAXI-44 eT –User Manual
GETTING STARTED GUIDE
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1SAFETY INSTRUCTIONS
1.1 General Information
•Please read carefully this operator manual before starting the system and follow its
prescriptions with the utmost care.
•In case the system was delivered with additional accessories, also read carefully the instruction
manuals of such accessories.
•Follow particularly the recommended instructions for Service and Maintenance.
•This Operator Manual is part of the delivery, hence shall be always kept together with the
instrument on its working place.
•It is imperative that every person operating this system has read and fully understood this
manual.
•The non-observance of the instructions contained herein or improper use may involve
damages/injuries not covered by product liability!
The national ruling and international safety norms in working environment shall in any case be
observed under user’s responsibility.
•It is also user’s responsibility to keep constantly updated all safety norms ruling in the country or
operation.
Information= indicates important information/recommendation for the user.
Attention = means that the warning non-observance may cause damages to unit or properties.
Warning = means that the warning non-observance may cause injuries, even severe, to people.
1.2 Safety in operations
•The unit shall be operated only according to its intended purpose.
•The unit shall only be operated within the power limits set by technical specifications.
•The unit shall be operated exclusively by specially trained people.
•All electrical parts shall always be protected from wet and humidity.
•The unit shall be kept clean.
•Basic rules of chemistry will always apply. The basic rules of chemistry are valid also for
chemicals handling. Working with chemicals, always take into account all safety measures
usually required (e.g. lab coat, protective gloves, protective glasses mask, exhausts hood, etc.)
1.3 Any unit manipulation allowed
Constructive changes/modifications of the unit and its accessories are forbidden.

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1.4 Maintenance and parts replacement
In order to guarantee the good functioning of the unit and user’s safety, all replacement parts shall be
exclusively original supplied by the manufacturer. The original parts are produced with particular
attention to quality and manufactory production.
1.5 Customer support
•The warranty certificate and qc report are included in the documents supplied with the unit.
•In case of unit reparation, please send us a service report with complete problem or damage
description.
•For any question or spare parts order, please contact our representative in your country or
directly Milestone.
1.6 Other hints
Please take into account all the safety measures when filling in the vessels before the run or when
opening the vessel, once completed the run.
Don’t label the vessels. Discoloration may occur on protection shield with the consequent
damage.
1.7 Working with accessories
The complete vessel system must be treated with the utmost care and regularly tested. In case of
damage, the corresponding components must be replaced. Please pay particular attention to the
chapter “Care and maintenance instructions”.

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2SYSTEM DESCRIPTION
2.1 Overview
The MAXI eT rotor (medium pressure rotor) contains up to 44 vessels (MAXI-44) for acid digestion of
easy to medium-difficult samples, such as soils, sludge, sediments, wastewater, food and feed,
pharmaceutical.
The MAXI eT rotor is totally controlled by contact- less easyTEMP sensor (T2) for temperature
control of each single vessel.
A high-quality PTFE vessel serves as well as chemicals and heat resistant. In order to prevent any
deformation, the reaction vessel is protected by a PEEK protection cover. This high-quality material
keeps the inner vessel fit and ensures a longer lifecycle of vessel systems.
2.2 Configurations
There are four different types of MAXI rotor depending on the maximum number and capacity of
vessels:
Rotor
Positions
Volume
(Vessel capacity)
MAXI-44 eT (80 ML)
44
80 ml
MAXI-44 eT (100 ML)
44
100 ml
2.3 Technical Specifications
Rotor
Min volume
Max volume
Recommanded
Working
Temperature
Max
working
pressure
Recommanded
Max Holding
Time
MAXI-44
(80ML)
5 ml
50 ml
200°C
35 bar
30 minutes
MAXI-44
(100ML)
5 ml
50 ml
200°C
35 bar
30 minutes
When exceeding the specified limit values, you must consider that the parts are subjected to
increased stress or damage. If you use the maximum routine conditions, a regular test of
vessel systems has to be carried out. All maximum values are reachable only with the suitable
materials.

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2.4 Temperature control
As mentioned above, MAXI eT rotor is controlled
by n°2 easyTEMP sensors. The sensors are
positioned on the bottom of the cavity in
correspondence of the rotor rings:
•Back-positioned sensor →internal ring
•Left-positioned sensor →external ring
Please, refer to Ethos UP/Ethos EASY User
manual for detailed info on the sensors.

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3VESSEL SYSTEM
3.1 Operations with MAXI-44, high throughput rotor
When working with MILESTONE rotors, observe all safety indications and specifications. The user must
be familiar with the operations with vessel systems. In addition, follow the operating instructions
reported in the microwave system user manual.
Weighing
In order to avoid erroneous changes among the vessels, the internal vessel should be immediately
closed and placed in the corresponding position of the numbered rotor.
Never label the vessels. The label color contaminates the protection shield and diffuses into
the vessel.
Place the cleaned vessel on the balance
Set the balance to zero (tare) and weigh the
sample.
Take note of the total weight or consider the
weight data on the terminal.
The weighing with the weighing paper and weighing boat is possible as option and reduces
e.g. the weighing errors due to electrostatic charge.

Milestone Srl MA210-002 –MAXI-44 eT –User Manual
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Chemicals addition
Add the necessary chemicals by the dosing station giving attention
to wet every possible part of sample left on the inner walls of the
vessel.
E.g. by carbonates replacement, sample/chemicals foaming or spray can occur. Take into
account the necessary precautions and wear the suitable protection equipment, such as
protection glasses, gloves, working under fume hood etc.
When dealing with digestions, Milestone suggests to let the samples react 5 up to 10 minutes before
closing the vessels. Before vessels closure, the sample must be well mixed with the acid, otherwise it
could result in severe partial reactions. For this purpose, there are several options: Vortex, stirring bar
etc. When handling samples with consequent gas development, a cover is placed on the vessel, in order
to avoid spray losses.
3.2 Vessel construction MAXI 34 / 44
Vessel 80 ml / 100ml
Cover
Vessel cover with thread

Milestone Srl MA210-002 –MAXI-44 eT –User Manual
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4OPERATIONS
4.1 Protection shield introduction
The below operations must be carried out only after Milestone specialist indications.
Once the shields have been installed, it will no longer be necessary to remove them from the rotor
body.
Shift the silicon protection ring on the lower
side of the protection shield.
The protection ring must be located on the
opposite of the tapered side.
Place the protection shield in the notch on the
bottom plate. The taper should be placed with
the face up.
Once introduced all the protection shields, place
the centering plate and screw it with its four
screws. Be careful that the marks (black points)
coincide.

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Place the lifting plate on the rotor and screw it
with its three screw nuts.
The rotor position 1 and the black mark should
coincide.
4.2 Vessel closure and installation
No special closure tool is required to close the vessel, but you can perform it by hands.
Place the little cover on the vessel. The pin on
the cover must face up.
Screw the thread cover on the vessel.
Place the closed vessel in the rotor.
A minimum number of 8 vessels must
be introduced in the cavity
For a better performance of the
Infrared Temperature Control (IR-TC)
sensor, in case of free rotor positions,
vessels must be distributed as
homogeneous as possible and firstly
on the outer circle positions.

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Introduce the rotor in the unit.
Select a method from the software library (the
method should be marked with “eT”).
Start the digestion method, and introduce the
number of vessels that you have loaded on the
rotor plate and wait the end of the program.
A minimum of 10 vessels must be
indicated to have a better
functionality of the system.
Press start and wait the end of the digestion
program. It’s possible to monitor the internal
temperature of each vessels from the sample
list / rotor window (see the Ethos UP user
manual for more details).
Wait for the end of the digestion program.
Warning
Open the vessels only when the
internal temperature is 80°C
In case of free rotor positions, the corresponding protection shields remain in the rotor.

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Never force the rotation of rotor by hand. This could damage the central PEEK adapter.
easyTEMP measuring settings can be found in the user manual of the Ethos UP.
For a better performance of the easyTEMP sensor, the “TWIST” function must be deactivated
(See the Ethos UP user manual).
4.3 Rotor removal
Remove the rotor by lightly raising it.
4.4 Vessel removal
For an easy removal of vessels (one by one) from rotor body, use the MAXI-44 Support
(LC000365).
Fix the MAXI-44 support to your ETHOS unit as
shown in the pictures
Move the rotor out of the cavity.

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Remove the vessels one by one.
For a fast removal of all vessels from rotor body, see the following instructions
Untighten the screw nut on the top plate.
Drag out the top plate by the handle with the
vessels facing up.
Place the lifting plate with the vessels on the
samples holder.
4.5 Vessel opening
Open the vessels only under a fume hood with a good suction power.
The vessel system must be cooled down, before its opening. In general a temperature of ca. 80°C is
recommended as reference value.
But this depends on the boiling point of the chemicals used and cannot be considered as limit value.
Before opening the vessel, the pressure has to be released, in order to avoid any fast over-pressure
release.

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During the opening of the vessels, some fumes
could come out from the vessels. Point the
vessels in the direction of suction of the fume
hood.

Milestone Srl MA210-002 –MAXI-44 eT –User Manual
GETTING STARTED GUIDE
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5CARE AND MAINTENANCE INSTRUCTIONS
5.1 General cleaning
All rotors should be regularly checked and cleaned. The rotors should be cleaned from acids or other
residues after each run, e.g. with diluted alcohol.
Water or acid residues should be thoroughly dried before use in the microwave, because they are
heated in the microwave and can lead to damages. This concerns particularly water or acid residues
between the PTFE inner vessel and the protection shield. For any question, contact Milestone or our
representative in your country.
In case acids, especially high boiling acids (e.g. sulfuric acid), reach the rotor bottom side, the whole
rotor must be washed with plenty of water and then completely dried (no water residue should be
present at the moment of microwave irradiation).
5.2 Rotor movement
In case of irregular rotor movement, check the bearings on the underside of the rotor body. If they
cannot be easily moved into the guide, there may be dust or dirt between the bearings and can be
removed using ethanol alcohol. The bearings can be sprayed with a little lubricant and release agent
based on PTFE.
5.3 Care and maintenance of IR (easyTEMP) sensor
The IR (easyTEMP) sensor calibration must be weekly tested following the instructions in
chapter “EasyTEMP Calibration Test instructions” (see the following chapter).
In case the test is not passed, the IR sensor must be cleaned. Then the calibration test must
be repeated.
To ensure a correct measuring by the IR sensor, the sensor lenses must be periodically cleaned from
impurities.
In case of contamination or unusual/abnormal program, the IR sensor must be cleaned after each run.
In case chemicals reach the sample chamber, the IR sensor must be properly cleaned and its
functionality must be tested in accordance with test prescription.
The IR sensor lens can be chemically attacked by HF vapours. The consequence of sensor lens
corrosion is lower measuring values.
Cleaning of IR (easyTEMP) sensors
The recommended cleaning procedure of easyTEMP sensor housing and lenses is the following:
1. Remove dust or possible solid residues from the IR housing. It can be easily done using a gas
duster (1) or compressed air (2), if available.
1
2

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2. Clean IR lenses with a cotton bud moistened with water. Cotton buds package (p/n 70484 –100
pcs) is included in the microwave system.
5.4 EasyTEMP Calibration Test instructions
Maxi eT rotor is monitored by two infrared (easyTEMP) sensors which are positioned in accordance to
the rotor rings. The calibration of each sensor must be tested separately.
eT sensor calibration test is based on the boiling point of water in an open vessel (atmospheric
pressure). At this working condition, the boiling point of water is unique and it can be used as reference
for sensor calibration check.
The boiling point of water depends on the elevation above the sea level. At sea level the boiling
point of water is 100 °C; at 1200 m it lowers down to 96°C. For the calibration test, this
variable data must be considered.
eT Calibration Test procedure
For the calibration test, a single MAXI vessel is
used.
Fill the vessel with 30 mL of DI water.
Place the threaded cover on the vessel,
without the TFM valve (open vessel
conditions).
Left-positioned eT sensor (MAXI external ring)
Place the vessel into the external ring of
the rotor (i.e. Pos.1).
Place the rotor into microwave cavity.
Close microwave door.
Enter the software library and select
“eT-Test” method from “Cleaning”
application folder.