Note: Descriptions are shown in the official language in which they were submitted.
l343~
This lnvention relates to a method of peat harvesting from
peatland.
Peat has been and still is used as fuel in many countries,
but only to a very limited extent in relation to the large
peat deposits found all over the world. According to certain
preli.minary investigations, the deposi-ts in Sweden alone have
a heat value corresponding to about 3 billion tons of oil.
The reason of the limited utilization of peat as fuel is, -that
the digging and handling methods known so far do not render
peat competitive with conventional fuels, especially with oil.
If, however:, -the oil continues to rise, peat in the ~elief of
many will become competi.ti.ve wit~ oi.l even when peat is harvestad
in the way as to-dav ~racticed predominatly in peat-digging ~:
countr.ies.
lhe said known method briefly comprises the steps of draining
by ditching the peatland and grading its surface, removing
stumps and trees, tilling the peatland across the entire graded
area with a rotarv -t-i.ller to a depth of some centimeters,
whereafter the tilled Peat laver is left to dry in the sun and,
` .
,
9~3~3~
2--
for accelerating the drying, is turned several times. After
drvina, the tilled peat is scraped together to windrows and
loaded on trac]ced dumpers or rail-bound carriages, which carry
the peat onto fi.rm ~round where the peat is reloaded on trucks
or railroad-~agons for transport to the Z?lace of consumption.
These steps~ viz. in due order tilling, drving and turning,
scraving and transporting from the dig~ing area, are under
favourable weather conditions repeated ten to fifteen times
per year. Thus, at a mean peat depth of 2 m for the entire
di~ging area, it takes at least ten years until the peatland
is fully utilized. First thereafter the restoring work can
be started for preparing the peatland for another production,
for example to plant so-called energy-production forest thereon.
For bein~, applied efficientlv~ the known peat-digging method,
which generally is called till-peat method, requires firstly
a) very large coherent plane areas of peatland
b) un;form carrvin~ capacity across the entire planned digging
area
c) absence of stumps, stones and the like, and
d) a peat de~th of at least 1.5 m across the enti~e digging
area.
The numher of peatlands suitable to be harvested is substanti-
all~J reduced by these requirements. When these peatlands, besides,
are reauired to be located near the consumption place, not
manv nZeatlands of the suitable ones are left. As an example can
be ment;oned, that for harvesting lS0 000 tons of peat with a
. .
~3~3~8
--3--
moisture content of 50%, an area of 500 to 1500 hectares is
required, depending on ~eat-her and peat depth.
The sai.d kno~n method, secondly~ reauires above a:ll very favour- :
able weather conditions during the short period free o.~ snow
at which the peat-digging method can be appli.ed at al:L. As the
weather cannot be influenced~ i.t is easily understood that this
method has a great disadvantage in being dependent on the -
weather and permitting digging only during a very limited period
of the vear,.and even this period being interrupted by longer
or shorter periods of rain.
The tilling of a new layer, practicall~.~, can be started first
after the tilled peat has dried and been removed from the
digging area.
The present invention, therefore, has the object to provide
a method of handling or digging peat from peatland which permits
substantially all existing peatlands exceeding, for example,
20 hec-tares to be harvested economically, which further permits
harvesting to take place substantiallv all the year, independ-
ently of weather,so that investments iTI machines are better
utilized and vari.ations in labour demand are reduced, and which,
~inally, nermits peat to be harvested to a great depth all at
one -time, irrespective of variations in the peat layer thickness, -~
therebv rendering possible harvesting also in cavities and
depressions in the ground, so that a greater proportion of the
peatland can be harvested and quicklv be restored for preparing
another productlon, for example thP planting of energy-producing
forest.
~:
- - - . , - - . , . . -:
:,
- ~ :-
L343~8
A method in accordance with the present invention
comprises the steps of digging the peat from a digging area
of the peatland to a maximum depth of the peatland at one
time with a mobile digging machine, discharging the dug
peat directly from the digging machine to a disintegrating
and separating apparatus which is connected to the digging
machine for following -the movement of the latter, continu-
ously disintegrating the peat and separating at least some
of the inherently present non combustible material from
the peat, as it is dug, in said apparatus, discharging the
disintegrated peat from the separating step continuously
to an endless conveyor system which is adjustable as to
its length, and continuously conveying the peat with the
conveyor system to a storage area outside of the drained
peatland and depositing the peat at the storage area in
at least one stack.
The invention is described in greater detail in
the following, with reference to the accompanying drawings,
in which:
Fig. 1 is a schematic key view of a peat-digging
area prepared for applying the method
according to the invention'
Fig. 2 shows in greater detail devices and
machines re~uired for carryin~ out an
embodiment of the method according to the
invention'
FigO 3 is a schematic later,l view of a means for
:;
, ~.i ' ..: !. . . ~
,, ' ,,,
~'~3~L3~ ~
- 4a -
transporting peat from the place of
digging to a place of stacking,
Fig. 4 is a schematic lateral view of a peat
stacker, and
Fig. 5 is a section through a stack of raw peat.
In Fig. 1 a peatland Located adjacent a road 1 is
prepared for digging after a digging plan established after
a survey of the peatland with respect to draining
possibilities, peat depth and extension. According to
this plan, the preparatory w~rk for the digging proper
is carried out which comprises cleaning of the area from
possible forest within the indicated cleaning boundary 2.
Long stems nct utilized for timber, and pulp wood are cross~
cut to lengths of at maximum 3 m and, when desired, can be
left on the mire within the digging boundary 3 indicated
in said plan. The peatland is drained by ditches 4, which
are connected to one or several trunk drains 5 with such
slope, that the ground water level by self-drainage can
lower itself
~'': , .:
I~9 '
i: ,: ~ - ; " ,
,.~ . . , . ~, . :: ., .... . ;. : - : - ~:
~ ~3~
somewhat below the lowest level, to wh.ich the peat can be excav-
ated. The peatland thus prepared then is leEt for selE-drainage
until the ground water level has reach-d the level desired.
Lhis may go on ~or one to three vears, dependin~ on weather
and wi.nd and other ci.rcumstan.ces. Th1s preparatory work can be
carri.ed out with any conventional equipment.
For carrvlng out the method according to the invention, it is
further nec~ssary to prepare a stacking place 6 on firm ground
in connection to the dig~ing area, on which ground excavated
peat can be stacked, and further a peat excavator, for example
a conventional tracked excavator 7 with a bucket of extra great
width 8 (Flg. 2), ~hich preferably perm;ts water to flow out
therefrom, lor excavatine~ peat, a means g for conveying excav-
ated peat from the excavator 7 to the stack;ng place 6, a
stacker 10~ an apparatus 11 disposed between the excavator 7
arld the stacker 10 for cutting-up the raw peat, and a certain
eguipment 12 for brea~ing-up the stacks, possibly by layers.
Said cutting-up apparatus 11, wlhich in Figs. 1 and 2 is shown
tracked and coupled directly to the excavator 7 to accompany ~.
the same, i.5 provided with a feed bi.n and compr.i.ses, besides
the means Eor cutting-up the peat, means capable to either
d;si.nte~ra-te or separate stumps, underwood or other tree parts ::
and s~ones, and a means ~or delivering in portions the cut-up
peat and, where appropriate, disintegrated tree parts to the
conveving means 9.
lhe said convevor brieflv comprises an endless conveying belt
~L3~398
-6-
20, which extends between the excavator or the cutting-up means
11 coupled thereto and a terminal 17. The conveyor preferably
is controlled via the excavator. The upper load-carrying strand
of the belt is susp~nded ;.n a manller substanti.ally tube- and/or
groove~shaped in pairs of support rol:Lers 13, which are carried
by a suPport wire 14,and by pairs o~ support rollers 13a~ some
of ~hich are suspended on poles 15 positioned in a spaced relation-
ship of, for example, 100 m to each other. Said poles carry
said supporti.ng wire and are mounted, pre~erably rotatably,,
on movable sleds 16, while the lower strand of the conveying
belt runs in spread state on support rolls located on`the
poles 15. The conveyor is arranged to extend from the place
where the excavation is to be started past the stacking place
into a cleaned wire-routel~, when such is required, where the
terminal 17 is located. The terminal is equipped with an autom-
atic support wire and belt stretching device 19, the stroke
length of which may be up to at least 20 to 30 m.
The excavation proper of the peat preferably is started from
the mire parts located farthest away from the stacking place 6
and is carried out, as already mentioned, by the excavator to
the maximum possible depth and in turns, which gradual:Ly
approach the stacki.ng place 6. The excavated wet peat, possibly
with wood material, is fed into the spaceous feed bin of the
cutting-up apparatus and i.n cut-up state discharged in suitable
amounts from the batching means onto the conveying belt 20.
The di.stance between the excavation place and the stacking place
6 decredses with continui.ng excavation, and accordingly also
the length of the convevor 9 is shortened by the automatic
~.: : ~ . , .:
_7_ ~3~3~
stretching device l9, which also permits the excavator 7 to
move within a relatively large area withou-t requiring poles
15 to be appreciably moved after~ When the distance to the
pole loca-ted closest to the excavator becomes too short, this
pole and possibly one more are moved a-fter and, if necessary,
the entire conveyor 9 is moved a~ter and into the wire-route 18.
The Cllt-Up raw peat is transported by the conveyor 9 to the
stackin~ place 6 where a movable unloading arrangement 21 ii
provided alon~ the conveyor 9 to transfer the cut-up raw peat
from the conveyor 9 to the stacker 10, which stacks the raw
peat -to high stacks 22 with sloping sides for free drying.
The stacker used may be a conveyor of the same type as the
feed conv yor shown and is supported at its end on a liftable
and lowerable extension arm 24 mounted on a wheel-stand 23, ~ -
which is mov,~ble in all directions. Depending on the distance
to the stack, one or more poles can be arranged between the
wheel-stand 23 and the unloadin~ arrangement 21 to carry the
convevor, i.e. the support wire 25 and the conveyor belt 26,
even over already existing peat stacks, when so is re~uired.
The stacker 10 also shall be equi~ped with a means ~or stretching
the support wlre and belt, though such stre~cher is not shown
in detail in the drawings.
The stacks are built-up in lavers to the shape and height desired.
Their width or diameter tapers toward their top for obtaining
slopin~ si;de sur~aces. The stacks can be given any shape, in-
, . ~ i i~ ; .: : ;
~343~8
~3 ,
clusive of both conical and pyramidal shape, thou~h the st~cks
shown in the clrawings have oblong" straight or arched shape.
Th;s shape is obtained when the discharge end of the stacker
is offset laterally first in one direction for 'la~ing one layer
and then i,n the opposite direction for laying the next layer,
and so on until full height is obtained. Each stack of raw peat
should be placed on a bed o~ ` sand or other material, which
prevents moisture migration from the 90il to the stack, but
Permits water to pass through in the opposite directiorl 9 if
the soil per se has no such properties. Generally, the soil
about and possibly beneath every stack should be drained, so
that water from the stacked ~eat as well as surface water always
ra~idly is conducted away from the stacking place 6, especially
;n the autumn and spring.
Every stack, as already mentioned, is built-up in layers with
a thickness of one to three meters, for example two meters.
This layer-structure a.o. has the effect that the water bound
lowermost ;n the stack of raw peat can escape before the next
layer is la;d. It also ;s possible to place drainage strips 23
between each peat layer. These strips extend through the ent;re
stack in the layer ;n question, e;ther horizontally or incl;ned
downward to one and/or the o~ther stack s;de1 and they preferably '
are laid so that the strips in one layer are located between
the strips in ad~acent layers. These drainage strips~ wh;ch
should project sl;ghtly from the stack s;des, facilitate and
accelerate efficiently the stack draina~e, i.e. the water flow
from the inner parts of the stack by gravity, which increases
wi,th the stack height. The dry;n~ is promoted substantially
..
~3~3~
g
by great stack height~ not only because of their large exposed
Peat surfaces, but also due to the speed of the ai.r stream
arising along the stack sides and increasing with the stack
height, whi.ch results in an efficient ~nd contlnuouo ventilation
of the surface layer of the stack even at low wind velocities.
lhis also ensures forced drying of the peat in the surface
layers of the stack during all times of the year when free
drying is possible. At evaporation from the stack surfaces said
air streams are directed downward due to temperature drop,
and at strong sun radiation the air streams are directed upward
due to the heating of the stack surfaces.
When one stack has been built-up to desired height~ the assembly
of the next stack is started immediately at necessary distance
from the completed stack, which remains undisturbed for some
ti.me ;.n order to dry. Due to the fact, that according to the
invention the raw peat is stacked directly after the excavation,
the excavation can take place independently of the weather
and all the year around, i.e. also in wintertime. At this time,
besides, the peatland ha.s a higher bearing capacity due to
frost, which normally does not reach down farther than to two
to follr decimeters~ not even in the northern parts of the
countrv, because of the insulating~ properties of the snow. For
digging ~eat in wintertlme, the eauipment must be completed bv
a snow 5 linger for removing snow as -the digging proceeds.
he method according to the present invention implies many
advantages. It permits to harvest large and small peatlands
,: ,,, , : . ::: : . .. .~ ,
-10- ~3~3~38
all the vear around, irrespective of weather and wind, and to
a great de?th a:L1 at one time, even at verying peat depths
within the area. The diggin~ can be adjusted to profile of
the Peat-moor bottom. The preparatory work before digging i9
reduced to a minimum, investments made in machines are better
ut;lized and~ above, all the digging costs per unit are sub-
stantiallv lower than at conventional digging miethods. Owing
to the concentrated digging to great depth according to the
inventîon, it also is possible to very quickly restore the
diggin~ area and convert it into a productive ground, thereby
reducing the nature conservancy problems possibly arising.
The present invention is not restricted to what is described
above and shown in the drawings, but can be altered and modified
in many different ways within the scope of the invention idea
set forth in the attached claims.
.:............... . ::
