Improved Process for Reducing Crude Peat into a Marketable Form.
Year: 1893

page_text: Date of Application, 30th May, 1893-Accepted, 23rd Sept., 1893
COMPLETE SPECIFICATION.
Improved Process for Reducing Crude Peat into a Marketable Form.
A communication from ALEXANDER ANDERSON DICKSON, of the Village of Cote
St. Antoine, in the District of Montreal, Quebec, Canada, Manufacturer.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
Peat is the organic matter of bogs, swamps and marshes and is consequently
composed of aquatic plants, mosses &c. in a decomposed state. In such condition
it is very fibrous, but owing to the large percentage of moisture it contains this
fibre is very easily broken if agitated or subjected to artificial heat before the major
part of the moisture has been eliminated from it.
Numerous attempts have been made to reduce peat to a marketable fuel, but
owing to the methods adopted, have proved futile, both in the Old and New Worlds.
The salient features of such attempts have been, after removing the crude peat
from the bog, to reduce the mass to a finely ground substance, something resembling
paste, some using a pug mill, others Ispecially devised machinery to pulverize it,
others adding water to assist in reducing it to a semi-fluid pulp, while others added
steam to assist in its assimilation.
As peat contains large quantities of gases, oils, tars and other volatile com-
bustible matter, the grinding, pulverizing and otherwise agitating it, liberated the
gases contained in the minute molecules, as well as mixed the solid or fibrous
matter with the water and when subjected to the action of heat necessary to dry it,
the major part of the volatile combustible matter volatilized and was carried off
with the vapor, and as it is impossible to express the moisture to any extent from
peat thus treated, except by intense artificial heat, the result has been a carbonized
fuel which contained only a small percentage of volatile combustible matter and
invariably costing many times what it could be sold for in order to produce it, the
result is to say that with hundreds of thousands of dollars spent, there is not a
successful peat fuel manufactory on the Continent.
This invention will be best understood by reference to the accompanying drawings
in which
Figs. 1 and 1 are two parts of the same side view of the apparatus used in the
carrying out of the improved process, the view being divided into two parts to
admit of its being shown on a sufficiently large scale.
Fig. 2 is a plan of the liquid-expressing rollers and
Figure 3 a transverse section of the tempering chamber.
By this invention an entirely new process for reducing crude peat to fuel has
been devised, which consists substantially in removing the peat from the bog by
any of the well known devices at present in use and after removing sticks, roots
and other obstacles, it is deposited in a hopper A, thence it is forced against a
porous surface, preferably cylinders B, arranged in the form of a triangle in such
a manner that the upper cylinder rests on the two lower ones thereby performing
the operations of two sets of cylinders. These cylinders, particularly the lower
ones, are hollow, being constructed on a frame, the outside periphery being of wood
or metal perforated and covered with a heavy coating of felt or other porous
surface to allow the water which is expressed from the peat while being carried
between the cylinders to fall into the interior from where it is carried by means of
spouts hanging on the centre shaft which act as conductors. It is preferable to
have the upper cylinder solid or the periphery solid to prevent the moisture
from being forced into its interior for if this were the case the water would be
continually draining through into the peat as there could be no means for removing

page_text: it, therefore the upper cylinder being without perforations, but covered with the
same substance as the lower ones, such as felt or any other material having a
porous surface to form a cushion, the moisture is thereby forced through the porous
coverings of the lower ones into their interior.
It is preferable to have the bearings of the upper cylinder arranged so that they
are held in place by means of springs to allow of a yielding resistance, thereby
allowing the said cylinder to move up and down automatically, accommodating
itself to the quantity of material passing between it and the two lower cylinders.
A bridge C is arranged for the purpose of conveying the peat from one cylinder to
the other in such manner that the upper cylinder can sweep the peat over the
bridge as it is scraped off the first one and is immediately conveyed to the second
cylinder where it is passed through and is ready to be carried to the tempering
chamber. It is preferable to drive the cylinders by a pinion which meshes into
gears attached to the ends of the two lower cylinders, the upper cylinder being
driven by a gear meshing into those of the two lower ones, but any other suitable
device may be used. It is preferred to have squeeze rollers Ñ arranged and
running horizontal with the full length of the cylinders for the purpose of
squeezing out the water that might remain in the felt or other material having
a porous surface. These squeeze rollers are preferably arranged on springs so
that they may apply great pressure to the covering of the cylinders as it is of
importance that the coverings or porous surface material should be kept as free
from water as possible. These squeeze rollers are preferably covered with rubber
or other elastic material.
The crude material being of a naturally fibrous or spongy nature, having thus
been deposited in the hopper A of the cylinders B and as it is drawn through,
receives a compress between the soft cushions or the felt or other porous material,
and the said material being as dry as possible, immediately absorbs the moisture
out of the peat and when it has passed through, the fibre of the peat immediately
assumes a spongy porous appearance, the fibre being still unbroken and with
approximately over one-half of the moisture absorbed. The partially dried peat
may then be deposited in a tempering chamber D, or if dry enough, may be imme-
diately compressed into fuel. The tempering chamber D is preferably constructed
in the form of a hollow cylinder revolved by any suitable means preferably from
the periphery. It is preferable to have this cylinder about twenty-five feet long
with a number of shelves E running lengthwise from the inlet to the outlet for the
purpose of elevating the partially dried peat and allowing it to drop down, and as
the cylinder is so arranged that it is a little lower at the outlet than at the inlet
the material is gradually carried forward by its own gravitation. Through this
cylinder it is preferred to carry a tube F perforated on all sides to allow of a
current of air, preferably heated or dry air to be used, so that the partially dried
peat, as it drops from the shelves E of the revolving cylinder D, falls and comes in
contact with the said current of air which has the effect of tempering the said
material and loosening the fibres preparatory to the final drying, if not already
sufficiently dry to compress into fuel. By this means a large percentage of the
moisture is removed from the peat and is being continually carried off through the
hopper at the inlet end.
It is preferred to use a fan to create a current of air, which is connected to
the perforated tube F by any suitable device and such air may be drawn from the
furnace of the drying chamber if desired, or from any other source. It is preferred
to have the outside of this tempering chamber covered with a non-conducting
material such as asbestos, or if found advisable, it may be heated from the outside
to further assist the current of air in tempering the peat.
It will be seen that up to the time that the material passes out of this chamber,
nothing has been introduced to disintegrate or break the fibre in any way and
when the outlet end is reached, the peat is comparatively free from moisture
retaining its natural fibre and consequently its volatile combustible matter.
The comparatively dry fibrous material may now be conveyed to the drying

page_text: chamber which is preferably in the form of a revolving vibratory cylinder or
cylinders constructed in such a manner that the peat is kept in such a state of
agitation to prevent carbonization, and it is further preferable to have it of a
radiant type so that the flame from the furnace cannot come in contact with the
cylinder, there being sufficient bridges to prevent anything but radiated heat from
reaching said cylinder. It is preferred to have the cylinder constructed in the
form of a series of cone frustrums I J arranged alternately, so that as the cylinder
is rotated, the peat is gradually carried forward to the larger end of the cone,
when it falls through suitable openings into the next larger cone and so on until
it finally drops out sufficiently dry to be compressed in any suitable form for
fuel. The peat being kept in a state of agitation by the rotating of the cylinder,
the moisture is rapidly absorbed by the atmosphere and the chamber in which
said cylinder is being rotated being heated by a suitable furnace constructed under
it with the necessary dampers to regulate the degree of heat required to sufficiently
dry the peat without allowing carbonization or of allowing the volatile combustible
matter from being driven off by excessive heating or drying. The whole material
being now in a loose dry fibrous condition, the agitation does not have the same
effect upon it and it may be agitated without danger of breaking the fibre.
It is preferred to have the rotating cylinder constructed in the form of a series
of cone frustrums, and the material being fed into it at the small end of the inner-
most cone J, it will, as the cylinder rotates gradually and by gravitation work
towards the outlet end, and when it will be ready to receive the final compression
to form it into the desired form for fuel.
It is preferable that the drying cylinder should be surrounded on all sides except
the outlet end with a brick or stone chamber for the purpose of retaining the heat
generated from the furnace underneath the rotating cylinder, the outlet end being
preferably exposed to allow of the free escape of moisture to prevent absorption by
the dry peat.
The dry material as it comes from the drying chamber may now be compressed
into the desired shape and form for fuel, and it is preferable to have the material
cold and the compression done in formers K of a round or cylinder shape with
plungers M operating therein and arranged so that the peat drops into a hopper or
hoppers L and is fed to the formers K by the plungers M at the inlet end of the
said formers. By this means the plungers force the dry fibrous peat into and
through the formers simultaneously expelling the air from the interstices of the
fibres, consolidating said fibres and forcing said material out of the outlet end of
the formers in a hard compact state similar to coal, the friction while passing
through such formers having coated the material with an atmospheric resisting
materia! which is indigenous to peat produced by this process. Each charge of
peat, as it is forced into the formers by the plungers, forms a resistance block for
the next successive charge and so on to the end of the chapter. There being no
artificial heat applied to the compression department, there is no danger of
bursting the formers by the generation of caloric which is very comnion when heat
is applied.
My correspondent has found in the course of his experiment with the compression
of crude peat, that there is a great difference in its specific gravity, that is to
say a mould, say three inches in diameter and twelve inches deep, will contain
when the peat is light and very fibrous about one pound in weight. The next
succeeding charge may be from a deeper strata consequently of greater specific
gravity and will probably weigh from twenty-five to thirty per cent. more, and if
compressed in a mould or former by means of a plunger working in such mould
with a permanent resistance block and the plunger turning to a fixed point like a
brick press, the result is that one block of peat will be very hard and compact and
the machinery is strained to even a breaking point, while the other block will
immediately fall to pieces. Now to obviate this difficulty and to save the machinery
from breaking, my correspondent has devised a means whereby every charge of
peat as fed into the moulds or formers is subjected to a uniform pressure and it is

page_text: immaterial whether the peat is of low or high specific gravity, each charge receives
a uniform pressure. It is preferred to have the moulds or formers K constructed
in the form of a tube, open at each end, the peat being driven in at the inlet end
and forced through the tube out of the outlet end. The peat forms its own
resistance block and advances out in proportion to the density of the crude peat,
thereby receiving a uniform compression before it is forced out in the desired form
for fuel. By this means the uneven compression created by a fixed tube or mould
is prevented and the moulds or formers are saved from fracture and the machinery
from severe strain.
My correspondent has also found that in some cases it is quite practicable to
remove sufficient moisture from the crude peat without the application of artificial
heat and that in such cases he can dispense with the drying chambers, using only
apparatus whereby the crude peat is forced against a porous surface until sufficiently
dry to be immediately formed into a marketable form for fuel.
It will be seen that the process is a continuous one, the utmost care being taken
to preserve the original natural fibre and it is preferable to compress the material
with this fibre unbroken, thereby reducing to a minimum the loss of volatile
combustible matter.
My correspondent does not wish to confine himself absolutely to the machinery
herein described to carry out this process, but may use any other similar device at
present in use or that may hereafter come into use.
Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what manner the
same is to be performed, I declare that what I claim is,—
1. The within described process of preparing peat by forcing the crude peat
against a porous surface provided with means for carrying away the water from
the peat substantially as and for the purpose specified.
2. The within described process for preparing peat by forcing the crude peat
against a porous surface provided with means for carrying away the water from
the peat and then carrying the peat through a chamber having a current of air
passing through it substantially as and for the purpose specified.
3. The within described process for preparing peat by forcing the crude peat
against a porous surface provided with means for carrying away the water from
the peat and then carrying the peat through a chamber having a current of air
passing through it and means for agitating the peat substantially as and for the
purpose specified.
4. The within described process of preparing peat first by partially drying it
without breaking its fibre then forcing it into one or more formers in such a manner
as to simultaneously form compress remove the air and coat the outer surface with
an atmosphere resisting substance without the application of artificial heat
substantially as and for the purpose specified.
5. The within described process of preparing crude peat by partially drying it
without disintegration then simultaneously forming compressing removing the air
and coating the outer surface with an atmospheric resisting substance in such a
manner as to preserve the volatile combustible elements indigenous to peat without
the application of artificial heat the whole substantially as described.
6. The within described process of preparing crude peat by partially drying it
without disintegration forming compressing removing the air coating the outer
surface with an atmospheric resisting substance preserving the volatile combustible
elements indigenous to peat in such a manner that each charge of peat receives a
uniform compression irrespective of the specific gravity of the crude material
without the application of artificial heat the whole substantially as described.
Dated this 30th day of May 1893.
W. P. THOMPSON & BOULT,
Agents for the Applicant.