Agriculture Reference
In-Depth Information
We will also present two further fibre
extraction processes: the turbine process and
extraction by steam explosion.
Having summarized the main steps of the
fibre extraction process, and in order to
illustrate the industrial production line, we will
present an example, that of Van Dommele-
Laroche (Fig. 9.6).
This illustration will now serve as the start-
ing point for a description of the most com-
mon fibre extraction process.
possible. A blower or aspirator may be
used to eliminate further dust and foreign
objects.
METAL DETECTOR
.
In general, at this stage of
straw processing, some sort of metal detec-
tion is used. Most commonly, the elimina-
tion of metal must be undertaken manually,
but systems also exist that allow the suspect
item to be redirected towards an outside
stock.
GUILLOTINE
.
The hay bale (with a diameter of
1.65 m and a weight of approximately 380 kg)
is placed on the belt and conveyed to the 'guil-
lotine'. This consists of a horizontal, hydrauli-
cally powered blade that cuts the straw into
pieces 30-50 cm in length (for other methods
of cutting straw, see box 9.5).
CRUSHERS
.
This is the heart of the fibre extrac-
tion process. Three main devices are used. As
shown in Fig. 9.6, two hammer crushers are
installed in order to ensure that the fibre is
cleaned as thoroughly as possible.
HAMMER CRUSHER
.
In order to reproduce the
mechanism of the old crushing machinery,
whose function was to crush the straw, a sys-
tem was designed that projected the straw
pieces on to a fast revolving cylinder, equipped
with mobile hammers.
The projected straw is caught in the space
between the cage and the cylinder. The ham-
mers are brought down on to the straw by
LOADER OR PRE
-
OPENER
.
The chopped straw
falls on to an inclined belt, which takes it to a
loader. The loader's role is to:
eliminate by gravity, stones and other
•
undesirable foreign objects;
spread out the straw into a bed that is as
•
homogeneous and as even in thickness as
Fibre cleaning No 2
Dust filtering
Dust filtering
Fibre cleaning using
Duvex1
Hammer crusher No 1
Cleaning and stone removal N°1
Press for cleaned hurds
First opener
Guillotine N°2
Press for loaded hurds
Hurds press
Guillotine N°1
Hurds silo
Bale convevor
Duvex for cleaning the hurds
Hammer crusher
N°2
Refinement line N°1
Refinement line N°2
Removal of very
small fibres
Press for short fibres
Fig. 9.6.
A diagram of the fibre extraction production line, Van Dommele-Laroche.
