BEHR CF 2 Plus 2 User manual

217201
User's Manual
CF 2+2 / CF 6
Device for Determining Crude Fiber Content
According to EN ISO 6865
Semi-Automatic with User Guidance
Firmware version 1.01

2© behr Labor-Technik GmbH
217201
Please read these operating instructions carefully before starting up your new
behrotest®device for determining Crude Fiber Content!
The operating manual gives clear and simple instructions for use of the apparatus.
In the interest of eliminating risk please observe the safety instructions given in this manual!
They are marked with a symbol.
Additional useful and important information on the functioning of the apparatus is marked
by a stripe in the margin.
We wish you every success in your work with the
behrotest® device for determining Crude Fiber Content!

3
217201
behrotest®CF 2+2 / CF 6
Safety advice
Danger of electric shock! Make sure that no liquids get into the cable connections or the
inside of the equipment.
There are no components inside the appliance which you need to operate. Repairs to
electrical equipment must be carried out only by trained specialists. Unplug the mains
plug before opening the appliance.
Glass can break and cause injury! In working with glass components, observe all appro-
priate safety precautions.
Be careful in working with corrosive substances! Follow the safety guidance in the perti-
nent Safety Data Sheets.
Caution: acetone and petroleum ether are inflammable! Perform all procedures working
with organic solvents in the optional defattening unit DG 2+2 / DG 6, not in the CF 2+2 /
CF 6. Empty the waste containers regularly; define whether the contents are to be recy-
cled or to be disposed of.
Appropriate Use
The CF 2+2 / CF 6 is only meant for use with diluted aqueos acids and bases,
not for use with organic solvents (danger of explosion) or with concentrated acids and bases.
Organic solvents or concentrated acids or bases could damage parts of the device.

4© behr Labor-Technik GmbH
217201
Contents
Safety advice...............................................................................................................................................3
Appropriate Use..........................................................................................................................................3
Scope of supply..........................................................................................................................................5
Parts list 5
Setting Up And Connecting ......................................................................................................................6
Some Routine Procedures With This Device...........................................................................................8
The Defattening Unit (optional) 10
Programming the CF 2+2 / CF 6 ............................................................................................................... 11
Adapting the CF 2+2 / CF6 to your requirements...........................................................................................12
Choosing the language 12
Configuring the level sensor 12
Setting the time 12
Cooling Water Source Setting 13
Setting the Date 13
Working with the CF2+2 / CF6 ................................................................................................................14
Preparing the Crucibles 14
Weighing the Samples In 14
Acid Digestion 16
Alkaline Digestion 19
Drying and Weighing 20
Incinerating and Weighing 20
Blank 20
Evaluation 20
Aborting Digestion 20
Manual Entry.............................................................................................................................................21
Modifying the Program 22
Maintenance and Care .............................................................................................................................25
Spare Parts and Accessories .................................................................................................................28
Consumables 28
Technical Data ..........................................................................................................................................29
Support .....................................................................................................................................................30

5
217201
behrotest®CF 2+2 / CF 6








Scope of supply
Please check the contents of the pack for com-
pleteness and freedom from damage immediately
upon receipt.
Claims resulting from damage during transportation
which is externally apparent must be lodged imme-
diately with the carrier (i.e., the post/mail service,
the railway administration, the freight organization,
etc.) - see the label on the packaging.
In case of damage which is not apparent from out-
side („concealed transportation damage“), please
contact the behr after-sales service immediately
upon discovery of the damage. The same applies
in the case of any other complaints.
Address:
behr Labor-Technik GmbH
Spangerstrasse 8
D-40599 Düsseldorf, Germany
Telephone: [phone]
Telefax: ([phone]
E-mail: [e-mail].
Please check the contents against the following list.
Parts list

Infrared-heated crude-fibre digestion unit
CF 2+2 / CF 6 for 4 or 6 samples, respectively
Heat-protection shield for CF 2+2 / CF 6
Crucible rack for docking to the CF 2+2 / CF 6
Transport gripper to simultaneously take the 4
or 6 crucibles out or insert them
4 or 6 filter crucibles, respectively,
packed separately

4 or 6 sieves to be inserted in the suction
nozzles

3 jugs,marked for water, acid, and base

2 heating plates

Funnel with prolonged outlet for filling in the
reagents
Hose set with the cooling-water hoses and the
waste-water hose.
In addition, you need a waste-water container
and, in case you are using the optional
defattening unit, collecting containers for the
acetone and petroleum ether.


6© behr Labor-Technik GmbH
217201
Setting Up And Connecting
Glass can break and cause injury!
In working with glass components,
observe all appropriate safety precau-
tions.
Place the infrared crude-fibre unit CF 2+2 / CF 6
on a flat level surface.
Hang the crucible rack on the hooks in front of
the crude-fibre unit.
Connect the waste-water hose of the crude-
fibre unit to the waste-water container
(optional).
Make sure the power switches of the devices
and, the case being, of the heating plates are
off.
Connect the infrared crude-fibre unit and, the
case being, the defattening unit to mains.
Inserting the sieves
The suction nozzles have stainless-steel sieves
laid in, to protect the pump from coarse particles in
case a frit should break. On delivery, these sieves
come packed separately.
Using tweezers, lay a sieve in each suction
nozzle.
If, later on, you want to change a sieve, take it
out of the nozzle with a pin.
Inserting the crucibles in the multi-crucible
snapper
On delivery, the filter crucibles and the heat shield
come packed separately; insert them in the device
now:
Insert the crucibles in the crucible rack.
Push the multi-crucible snapper on the
crucibles.
Inserting the crucibles in the device
Release the lock lever by pressing it down a
bit and pulling the locking grip towards yourself
with your thumb.
Let the lever come up to the end position;
release the locking grip as soon as the lever is
out of the lock position.
Insert the crucibles in the device.
Push the lock lever down until it engages.Now
the crucibles are locked.
Later on, you won't ever grasp the crucibles one by
one but insert them in the device using the multi-
crucible snapper, and get them out or transfer them
to or from the optional defattening unit.












Insert the crucibles
in the crucible rack ...
... and press the multi-crucible
snapper on the crucibles

7
217201
behrotest®CF 2+2 / CF 6
Inlet hose has
screw connections
on both ends
Outlet hose is a
thin polyamide hose;
push into the socket
as far as it will go
Inlet
Tap Water
(screw
connection)
Outlet
Tap Water
(quick push-in
connection)
Inserting the heat shield
Hang the heat shield on the hooks on the front
of the device.
Cooling-water connections
The cooling-water inlet hose has 3/4" screw con-
nectors on both ends.
Screw the cooling-water inlet hose to the
socket marked "Inlet Tap Water".
Connect the inlet hose to a water tap.
Push the cooling-water outlet hose (black poly-
amide hose) into the socket marked "Outlet Tap
Water" as far as it will go and lay it to a sink.
Open the water tap.
The CF 2+2 / CF 6 crude-fibre unit can only
be operated if cooling water is on. If you try
operating it without cooling water, an error
message willl appear, and the software cannot
be started.






8© behr Labor-Technik GmbH
217201
Taking Out and Inserting the Crucibles
Crude-Fibre determination with the CF 2+2 / CF 6
is performed with the same filter crucibles for
digestion, filtration and incineration. The crucibles
are locked under the condensers of the digestion
device. In order to insert the crucibles, to take them
out or to transfer them from the digestion device
to the defattening device and back, there's the
multi-crucible snapper. It makes you sure not to mix
the samples up. (On delivery, the crucibles came
packed separately.)
If you unlock the lock lever without
gripping the crucibles before with the
multi-crucible snapper, the crucibles
will fall out of the device and break.
So always grip the crucibles with the
multi-crucible snapper, then unlock
the lock lever and take the crucibles
out simultaneously. Doing it this way,
you always have the crucibles in the
proper order and are sure not to mix
the samples up.
During a digestion, the crucibles are concealed
behind the heat shield. In order to take the
crucibles out after digestion and filtration, you need
first to take the heat shield off.
Grasping the heat shield with the handle, lift it
up a bit so the two "keyholes" will pass over the
pins that are holding it.
Take the heat shield off and lay it aside.
Now push the multi-crucible snapper on the
crucibles that are locked in the device. You will
need to press quite firmly until all four or six
spring clips have properly locked on the cruci-
bles.
Now you can unlock the crucibles:
Release the lock lever by pressing it down a
bit and pulling the locking grip towards yourself
with your thumb.
Let the lever come up to the end position;
release the locking grip as soon as the lever is
out of the lock position.
With the multi-crucible snapper, take the cru-
cibles out of the device and insert them in the
crucible rack in front of the device.
In order to insert the crucibles in the device again,
proceed in inverse direction. In the same way insert
the crucibles in the optional defattening unit DG 2+2
/ DG 6 and back out.






Some Routine Procedures With This Device

9
217201
behrotest®CF 2+2 / CF 6
Filtrating
The samples in the digestion vessels will be differ-
ently easy to filtrate, even if they are of the same
material - maybe the sample weights are slightly
different, or one sample has got more filter aid
added than the other.
If you try to filter all these samples simultaneously,
the fastest one will already be sucking air while
others, may be, have got clogged. So don't do that;
filter them one by one. This is the way it is arranged
in the software.
When the program asks you, turn the valve
into "Vacuum" position, confirm by pressing the
control knob and let the pump drain the content
of the vessel. Turn the valve back to "Closed"
before opening the next one.
Blowing the frits free
On cooking with acid and then with base, part of
the sample material is dissolved. Sometimes the
remaining part will consist of very fine particles that
will clog the frit on filtrating. In order to get the frits
free again, the washing procedures of the program
have a part where air is blown through the frit.
In the software, an overall aeration time is given
that is meant for all samples together. The display
will always show the remaining aeration time.
Turn the valves, one after the other, cautiously
into "Pressure" position and have air blown
through the frit.
If the frits had not been clogged in the first
place, blowing might cause part of the sample
to be splashed up into the condensers from
where it needs to be rinsed back in the
next steps. To prevent this, turn the valves
cautiously.
After a few seconds, the frit should be free again.
Turn the valve back to "Closed" before blowing
the next frit free.




10 © behr Labor-Technik GmbH
217201
The Defattening Unit (optional)
The determination procedure of crude fibre has
some steps operating with volatile organic solvents.
Before starting the digestion itself, the sample is
treated with petroleum ether to remove fat. After the
acid digestion step it can be necessary - depend-
ing of the nature of the sample - to remove another
fraction of fat; in this case the wet sample must be
treated with acetone first to remove water. And at
the very end, the sample is washed with acetone to
make drying easier.
These procedure steps must not be carried out in
the CF 2+2 / CF 6 digestion unit. For these steps
there is the optional defattening unit DG 2+2 / DG 6.
The defattening unit has no condensers and no IR
radiator or any other kind of heating, but, instead,
it has two separate suction pumps so you can col-
lect acetone and petroleum ether separately and
decide if and how they are to be recycled.
The procedure of locking and unlocking the cruci-
bles is the same for the optional defattening unit as
for the IR digestion unit.

11
217201
behrotest®CF 2+2 / CF 6
Press button for
enter / stop
–+
Programming the CF 2+2 /
CF 6
The operating control unit
Your crude-fibre unit CF 2+2 / CF 6 is programmed
and operated easily with a single knob.
The principle remains in all cases the same:
Turning the knob enables you to choose an option.
The currently addressable option is recognized by
being highlighted with green text on a black back-
ground.
The knob may be turned in both directions. In doing
this, you will pass all possible options in the display
shown and will always again find the desired option
on continued turning. Try this for yourself.
The desired option is implemented by pressing on
the knob.
The complete procedure of choosing by turning
and implementing by pressing will henceforth sim-
ply be called “selecting”.
The following pages will show you how to program
and operate your crude-fibre apparatus.
For you being able to switch the device on,
the cooling water must be on; otherwise
on switching on there will only be an error
message.
After switching on and initialization you will see the
following display:
This is the main menu. From here you come to all
other menus and displays.
The option START is pre-programmed as a default
setting.
START
OPTIONS
PROGRAM 01

12 © behr Labor-Technik GmbH
217201
Adapting the CF 2+2 / CF6
to your requirements
Your crude-fibre digestion apparatus can be
adapted to a significant degree to accommodate
your personal requirements and those of your work
environment.
To do this, first select Options in the main menu
and then select Device in the sub-menu.
You will find several options.
Choosing the language
Language This enables you to choose the lan-
guage of the display.
These languages are available:
D = German
GB = English
F= French and
one additional language, which
you may have possibly specified in
purchasing your behr CF 2+2 / CF 6.
Configuring the level sensor
Contai-
ner
Switches the level sensor for the
waste container on or off.
The factory default setting is Off.
Switch the setting to On, if you are
using a level sensor. If you are not
using the canister set, then do not
change the factory default setting.
Setting the time
Time Set the time of day using the opera-
ting control knob.
Once all settings in this menu have been made in
accordance with your requirements, you can pro-
ceed to the next menu using ==>>.
Aerate
Drain
<<== back
Off
Off
START
OPTIONS
PROGRAM 01
Language
Container
Time
<<== <<==
Off
08:14
GB

13
217201
behrotest®CF 2+2 / CF 6
Cooling Water Source Setting
Cool water The factory default setting is Off.
Do not change this setting if you
have connected the digestion
apparatus to a cold water tap.
Cold water will only be drawn
from the tap during actual dige-
stion.
Select On, if you are using a cir-
culating water cooler.The cooler
will circulate cold water . The
cooling water will circulate conti-
nuously as long as the crude-fibre
digestion apparatus remains swit-
ched on.
Follow the instructions in the
operating manual provided
with your circulating water
cooler.

Select ==>> to proceed to the next menu, or
<<== to return to the previous menu.
Setting the Date
On the third page of the Device Menu you can
set the current date. Select and modify the Year,
Month and Day entries separately.
Select <<== to return to the previous menues.
Cool.Water
<<== back <<==
Off
Month
Day
Year
<<== back
07
20
2017

14 © behr Labor-Technik GmbH
217201
Working with the CF 2+2 /
CF 6
Preparing the Crucibles
Charging the crucibles with filter aid may be car-
ried out in the optional defattening unit. To do this,
the filter aid is suspended in water and then filtered
with the defattening unit.
Approx. 2 g Celite 545 filter aid are suspended
in about 50 ml dist. water.
In the unit the crucibles are inserted with the
multi-crucible snapper and locked by press-
ing the black lock lever on the left side of the
device down. Now the valves are turned each
from "Closed" to Acetone / Water position.
By acting the left green push-button the pump
is switched on and the Celite suspension is
filtered.
Then one washes with a little acetone and dries
the crucibles about 2 - 3 hours at 130 °C in the
drying cupboard. After cooling down in the des-
iccator, the crucibles are weighed on an ana-
lytic balance, and this procedure is repeated up
to constant weight.
Weighing the Samples In
Depending on the nature of the sample material,
add about 1 g of sample into each prepared
crucible.
Sample weight: w1
In the formula for calculating the crude fibre
content, the sample weight w1is a net weight,
i. e. just the weight of the sample material
without the crucible and the filter aid. But the
weights w2and w3are measured as gross
weights, including the crucible and the filter aid.
Has someone made a mistake?.
No - on calculating the loss on ignition, w2- w3,
the weight of the crucible and the filter aid is
part both of w2and w3, so it will just cancel out.
The loss on ignition resulting from this is thus a
net value anyhow.




Suspend Celite®in water to
achieve a clear solution

15
217201
behrotest®CF 2+2 / CF 6
For samples rich in fat: Defattening
(Defattening unit optional)
If the sample material has more than 10% fat, the
samples need to be defattened.
Caution: acetone and petroleum ether
are inflammable! Perform all proce-
dures working with organic solvents in
the optional defattening unit DG 2+2 /
DG 6, not in the CF 2+2 / CF 6.
Insert the crucibles containing the samples into
the defattening unit DG 2+2 / DG 6.
Turn all valves in "Closed" position.
Pour 30 ml petroleum ether 40 - 60 °C into each
crucible.
With the right switch, switch the petroleum-
ether suction pump on.
Now turn the first valve in "Petroleum" position
and have the first sample sucked dry.
Turn this valve back to "Closed", and have the
second and all other sample sucked dry, one
after the other, in the same way.
Repeat the defattening procedure twice more:
for each step, pour 30 ml petroleum ether in
the crucibles, turn the valves, one by one, to
"Petroleum" position, have the sample sucked
dry and close the valve again.
Decalcifying
If the material contains much carbonate (more than
50 g/kg measured as calcium carbonate), it must
be decalcified. The decalcification step can be per-
formed in the DG 2+2 / DG 6 as well. The hydro-
chloric acid is miscible with acetone, so suck it with
the acetone pump into the acetone container.
If it has not yet been done, insert the crucibles
containing the samples in the defattening unit
DG 2+2 / DG 6.
Turn all valves in "Closed" position..
Pour 30 ml of 0.5-molar hydrochloric acid into
each crucible and let it work for one minute.
Switch the acetone suction pump on with the
left switch.
Now turn, one after another, each of the valves
into "Acetone" position and have the content
of the crucible sucked dry. Then turn the valve
back to "Closed" before opening the next one.
Repeat the procedure twice more with each
sample.














16 © behr Labor-Technik GmbH
217201
Acid Digestion
Heat the amount needed of diluted (0.13 molar)
sulfuric acid almost up to boiling temperature
on a heating plate. For a series of the CF 2+2
you need 4 x 150 ml = 600 ml, for the CF 6 you
need 900 ml.
Never run a digestion without liquids
and add the liquid as soon as the
prompt appears. Heating an empty
apparatus can make the crucibles
burst.
Insert the crucibles containing the samples in
the CF 2+2 / CF 6.
Switch the CF 2+2 / CF 6 on, and wait for the
Start menu to appear.
Push the control knob. This will start the Crude
Fibre software.
The digestion will now run semi-automatically:
Heatings and pumps will switch on or off whenever
the digestion program needs them to. If an action
of yours is required, a message on the display will
appear, saying, for example, that now you have to
fill the acid in. In this case, follow the instruction
and confirm by pushing the control knob. As soon
as you have pushed the button, the program will go
on.
Turn all the valves in "Closed" position. Push
the control knob for confirmation.
The device will preheat for the preheating time
set in the program. Then it will ask for adding the
sulfuric acid.
Insert the filling funnel into the first digestion
vessel and fill 150 ml hot 0.13 molar sulfuric
acid in. Do the same with the other sample
places.
The prolonged, heat-isolated outlet of the fill-
ing funnel allows to fill in the hot acid or base
without it cooling down again just from running
down through the condenser.
When you have added the sulfuric acid to all
sample vessels, push the control knob.
The device will heat the samples for the time given
in the program.
In the meantime, put the jug with distilled water
on the heating plate so it will be ready for the
washing steps.
When digestion time is over, an instruction will
appear to turn the valves to Vacuum position.
If you try to filter the samples simul-
taneously, the pump will draw air as
soon as the first sample has been
sucked dry. Filter the samples one by
one in the order the program asks you.








START
OPTIONS
PROGRAM 01
Valve
Close
PROG.NUMBER
H SO Digestion
2 4
01
confirm !
PROG.NUMBER
H SO Digestion
2 4
01
Preheating
02:42
PROG.NUMBER
H SO Digestion
2 4
Addition
H SO 150 ml
2 4
confirm !
01
PROG.NUMBER
H SO Digestion
2 4
01
Cook
28:42
Sample 1
at Vacuum
confirm !
PROG.NUMBER
H SO Digestion
2 4
01

17
217201
behrotest®CF 2+2 / CF 6
PROG.NUMBER
KOH Digestion
suction
Sample 1 19
01
Valve
Close
PROG.NUMBER
H SO Digestion
2 4
01
confirm !
Addition
H O 150 ml
2
confirm !
PROG.NUMBER
H SO Rinsing
2 4
01
Turn the first valve to "Vacuum" position and
push the control knob.
The suction pump will now run for the time
specified. When time is over, a prompt will appear
to close the valve. Then the program will ask you
to open the next valve and so on until all samples
have been drained. For each action you need to
push the control knob to confirm it.
Blowing free and rinsing
A prompt will appear demanding addition of
water. Insert the filling funnel and fill the pre-
scribed amount of water in, for one vessel after
the other.
When you are through with this, push the con-
trol knob. The aeration pump will start running.
An instruction will appear to turn the valves to
Pressure. Aeration time (in seconds) dis-
played on the screen is counted for all sam-
ples together. Cautiously turn each valve in
turns to Pressure for a few seconds, and back
again.
If the frits had not been clogged in the first
place, blowing might cause part of the sample
to be splashed up into the condensers from
where it needs to be rinsed back in the
next steps. To prevent this, turn the valves
cautiously.
When aeration time is over, the prompt will appear
to turn valve 1 to Vacuum.
Turn the first valve to "Vacuum" position and
push the control knob.
The suction pump will run for the time specified,
just as before. The samples will be filtered one after
another, and each time the software will prompt
you to switch the valves and push the control knob.
Rinsing will be repeated the number of times set in
the program (the preset is 3 times). After this, the
program will ask if you want to repeat rinsing. If you
answer Yes, the rinsing process will repeat itself.
If you answer No, the program will go to the next
step.





Repeat
rinsing?
No Yes
Prog.Number
H2SO4 rinsing 01
Valve
at Pressure
confirm !
PROG.NUMBER
H SO Rinsing
2 4
01

18 © behr Labor-Technik GmbH
217201
Intermediary step: second defattening
Caution: acetone and petroleum ether
are inflammable! Perform all proce-
dures working with organic solvents in
the optional defattening unit DG 2+2 /
DG 6, not in the CF 2+2 / CF 6.
With samples that contain very much fat, it may be
necessary to defatten once more before the alka-
line digestion. Since the material is wet now, the
water is first supplanted with acetone before defat-
tening with petroleum ether.
Insert the crucibles containing the samples into
the defattening unit DG 2+2 / DG 6.
Turn all valves in "Closed" position.
Pour 30 ml acetone into each crucible.
With the left switch, switch the acetone suction
pump on.
Now turn the first valve in "Acetone" position
and have the first sample sucked dry.
Turn this valve back to "Closed", and have the
second and all other sample sucked dry, one
after the other, in the same way.
Switch the acetone suction pump off and the
petroleum ether suction pump on instead.
Pour 30 ml petroleum ether 40 - 60 °C into each
crucible.
With the right switch, switch the petroleum-
ether suction pump on.
Now turn the first valve in "Petroleum" position
and have the first sample sucked dry.
Turn this valve back to "Closed", and have the
second and all other sample sucked dry, one
after the other, in the same way.
Repeat the defattening procedure twice more:
for each step, pour 30 ml petroleum ether in
the crucibles, turn the valves, one by one, to
"Petroleum" position, have the sample sucked
dry and close the valve again.












Defatten?
No Yes
PROG.NUMBER 01

19
217201
behrotest®CF 2+2 / CF 6
Alkaline Digestion
Heat the amount of diluted (0.23-molar) potas-
sium hydroxide solution on the heating plate
almost up to boiling. For a series of the CF 2+2
you need 4 x 150 ml = 600 ml, for the CF 6 you
need 900 ml.
Insert the crucibles containing the samples in
the CF 2+2 / CF 6.
Turn the valves in "Closed" position and push
the control knob to confirm.
The device will now demand addition of the potas-
sium hydroxide solution.
Insert the filling funnel into the first digestion
vessel and fill 150 ml hot 0.23 molar potas-
sium hydroxide in. Do the same with the other
sample places.
The prolonged, heat-isolated outlet of the fill-
ing funnel allows to fill in the hot acid or base
without it cooling down again just from running
down through the condenser.
When you have added the potassium hydroxide
to all sample vessels, push the control knob.
The samples will now be heated for the time set in
the program.
In the meantime, put the jug with distilled water
on the heating plate so it will be ready for the
washing steps.
When digestion time is over, an instruction will
appear to turn the valves to Vacuum position.
If you try to filter the samples simul-
taneously, the pump will draw air as
soon as the first sample has been
sucked dry. Filter the samples one by
one as the program demands.
Turn the first valve to "Vacuum" position and
push the control knob.
The suction pump will now run for the suction time
set just as before. The samples will be drained
one by one, and the program will ask each time to
switch the valves and to pushg the control knob.
After this the samples will be rinsed with water just
the same as after the acid digestion. Rinsing will be
repeated as often as specified in the program. After
the last rinsing the program will ask if you want
to repeat rinsing. If you answer Yes, the rinsing
process will repeat itself. If you answer No, the
program will go to the next step.







Addition
KOH 150 ml
confirm !
01
PROG.NUMBER
KOH Digestion
01
Cook
29:17
PROG.NUMBER
KOH Digestion
Sample 1
at Vacuum
confirm !
01
PROG.NUMBER
KOH Digestion
PROG.NUMBER
KOH Digestion
suction
Sample 1 19
01
Repeat
rinsing?
No Yes
Prog.Number
KOH rinsing 01

20 © behr Labor-Technik GmbH
217201
Drying and Weighing
Caution: acetone and petroleum ether
are inflammable! Perform all proce-
dures working with organic solvents in
the optional defattening unit DG 2+2 /
DG 6, not in the CF 2+2 / CF 6.
Insert the crucibles containing the samples into
the defattening unit DG 2+2 / DG 6.
Turn all valves in "Closed" position.
Pour 30 ml acetone into each crucible.
With the left switch, switch the acetone suction
pump on.
Now turn the first valve in "Acetone" position
and have the first sample sucked dry.
Turn this valve back to "Closed", and have the
second and all other sample sucked dry, one
after the other, in the same way.
Repeat this acetone rinsing twice more with
each sample.
Put the crucibles on incineration dishes and dry
them for 2 hours in the drying cupboard.
While drying and incinerating, parts might chip
off the filter crucibles, and that would distort
your analysis result. So place the crucibles on
incineration dishes for drying and incinerating
and weigh them with the dishes.
Weigh the crucibles with 0.1 mg accuracy.
Incinerating and Weighing
Place the crucibles with the incinerating dishes
in the muffle furnace and incinerate at 500 °C
(±25 °C).
Do not use a higher temperature - otherwise
the frits would sinter and get useless.
Place the crucibles with the incinerating dishes
in a desiccator to let them cool down.
Weigh the crucibles with the incinerating dish
with an accuracy of 0.1 mg.
Incinerate once more, let the crucibles cool
down and weigh again till the weight remains
constant for 2 mg at most.
Blank
Use one of the four or six sample places to do
a blank. For the blank, just apply approximately
the same amount of filter aid and treat it with the
same reagents as the samples. The blank must not
exceed 2 mg.













Evaluation
Sample weight: w1
Weight after drying: w2
Weight after incinerating: w3
(in grams each)
Then the Crude Fibre content results as the
loss on incineration as a fraction of the sample
weight::
wf= (w2- w3) / w1
In order to get the result expressed in g / kg,
enter the values in the numerator, w2and w3,
in milligrams or - which is the same -
divide the result by 1000.
The result should be given in full g/kg.
Aborting Digestion
During the pre-heating and cooking phases, you
can interrupt or abort the program.
On pushing the control knob during the pre-heating
or cooking phase, a prompt will apppear to ask if
you just want to shortcut this heating process or to
abort the entire program. The preset is No cancel..
cancel ?
PROG.NUMBER
H SO Digestion
2 4
01
only cook
whole program
no cancel
If you select Only cook or Whole program, the
program will ask, to be sure, if you really want to
abort.
If you have decided to abort the whole program,
there will be a final rinsing step; then the program
will be aborted.