Improvements in or relating to the Combustion of Fuel.
Year: 1894

page_text: Date of Application, 11th May, 1894
Complete Specification Left, 11th Feb., 1895-Accepted, 23rd Mar., 1895
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Combustion of Fuel.
I, CONSTANZ SCHMITZ, of 21 Waldenserstrasse, Berlin, Germany, Engineer,
do hereby declare the nature of this invention to be as follows:-
All arrangements hitherto employed for the combustion of coal-dust possess the
disadvantage that the coal-dust is introduced directly into the furnace or other
fire-place (hereinafter referred to as a furnace) and consequently it does not
become intimately mixed with air so that a portion of the coal escapes unburnt
and falls down in the flues or passes away as smoke through the chimney. More-
over the quantities of the coal-dust and the air that are introduced cannot be caused
to preserve the same ratio to each other; so that an increase in the quantity of
air introduced is not necessarily accompanied by a correspondingly greater supply
of coal-dust; and the effect thus produced is contrary to that intended, as the
excess of cold air cools the furnace and thereby prevents the ignition and effective
combustion of the coal-dust. Besides, the working of these furnaces is often
irregular, because the apparatus employed for feeding the coal-dust into the
furnace very frequently gets out of order, e.g. by a lump of coal or by coal-dust
agglomerated by damp. Also, it has hitherto been found impossible in these
furnaces to accelerate the combustion to the desired extent.
Now according to my invention I obviate these disadvantages by preparing and
employing an intimate mixture of coal-dust and air whose composition is always
that necessary for obtaining the most advantageous combustion of the kind of
coal-dust that is being used. Such a mixture stored up and introduced into the
furnace as required will always secure the efficient and smokeless combustion of
the coal. The correct composition and the required uniformity of the mixture can
be attained outside the furnace only. The separation of the pure coal-dust from
impurities should precede the preparation of the mixture.
To effect this separation I use the same air that is afterwards to be mixed with
the coal-dust; and in order to do this I introduce the coal-dust mixed with
impurities into a current of air by which it is carried along for some distance, and
whilst being thus carried along the impurities and larger pieces fall down, as the
velocity of the air-current is so adjusted that practically only fine particles of
coal-dust can be carried by the current for the whole distance. The air and the
fine coal-dust then enter together into a chamber (hereinafter referred to as the
store-chamber), in which they are stored up as a finished mixture and are introduced
as required into the furnace. In this store-chamber the air is kept in continuous
motion. The air in the store-chamber will hold in suspension a percentage of
coal dust that will vary in a regular manner with the velocity of the said air
provided there be sufficient coal-dust in the said store-chamber; so that even if
the coal-dust be introduced in excess into the store-chamber the air therein will
hold in suspension only the percentage of coal-dust that corresponds to the velocity
with which it may be moving. By altering the velocity of the air in the store-
chamber the percentage-composition of the mixture of air and coal-dust may
therefore be altered so as to correspond to the kind of coal employed. When a.
certain quantity of air is fed from the store-chamber into the furnace there will be
thus supplied with it as large a quantity of coal-dust. as the said quantity of air
will be capable of burning. A decrease or increase in the air supply to the
furnace will at once cause a corresponding decrease or increase in the quantity of

page_text: !
coal-dust supplied with it, as the percentage-composition of the mixture is always
the same provided the velocity of the air in the store-chamber remains unaltered.
This percentage-composition is altered only by the velocity of the air in the store-
chamber and is independent of the quantity of air taken therefrom.
The accompanying diagrammatic drawing shows, by way of example only, an
arrangement of apparatus suitable for carrying my invention into effect. From a
hopper A the coal-dust with its impurities is conducted by means of a feed
roller B or other suitable device into a current of air, which may be produced by
means of a fan C or by any other suitable apparatus. This air-current carries
the coal-dust-through a conduit D into the store-chamber F. The velocity of the
air whilst passing along the conduit D is so adjusted as to allow anything suspended
in it and heavier than the fine coal-dust, such as larger pieces of coal and mineral
admixtures to fall down and be collected in a vessel E. In the store-chamber F,
the air arriving from the conduit D and still holding the coal-dust in suspension is
kept in motion by means of a fan G; the air in the store-chamber F may, however,
be kept in motion by means of the fan or its equivalent only or by any other
suitable means. The velocity of the air is so adjusted that it holds in suspension
exactly as great a percentage of coal-dust as it can burn in the most advantageous
manner. When a larger quantity of coal-dust is introduced into the store-chamber F
than the air in motion therein is capable of maintaining in suspension, the excess
thereof falls down and is collected at the bottom of the store-chamber, whence it is
discharged from time to time into a vessel H placed underneath the said store-
chamber. From the store-chamber F the mixture of coal-dust and air is carried
off through one or more conduits J and led by means of a fan or its equivalent or
by the natural draught into one or more furnaces. The arrangement of these
furnaces may be of any known or suitable kind, the combustion taking place, say,
on fire-bricks, whilst in kindling the fire an ordinary grate or any other known or
suitable arrangement may be used.
:
I, CONSTANZ SCHMITZ, of 21 Waldenserstrasse, Berlin, Germany, Engineer,
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 :-
All arrangements hitherto employed for the combustion of coal-dust possess so
far as I am aware, the disadvantage that the coal-dust is introduced directly into
the furnace or other fire-place (hereinafter referred to as a furnace) as soon as it
is formed, and consequently it does not become intimately mixed with air so that a
portion of the coal escapes unburnt and falls down in the flues or passes away as
smoke through the chimney. Moreover the quantities of the coal-dust and the
air that are introduced cannot be caused to preserve the same ratio to each
other; so that an increase in the quantity of air introduced is not necessarily
accompanied by a correspondingly greater supply of coal-dust; so that the effect
produced is contrary to that intended, as the excess of cold air cools the
furnace and thereby prevents the complete ignition and effective combustion of
the coal-dust. Besides the working of these furnaces is often irregular, because
the apparatus employed for feeding the coal-dust into the furnace very frequently

page_text: gets out of order, e.g. by a lump of coal or by coal-dust agglomerated by moisture.
Also, it has hitherto been found impossible in these furnaces to accelerate the
combustion to the desired extent.
Now according to my invention I obviate these disadvantages by preparing
and employing an. intimate, mixture of coal-dust. and air: whose composition is
always that necessary for obtaining the most advantageous combustion of the kind
of coal-dust that is being used. Such a mixture stored up and introduced into the
furnace as required will always secure the efficient and smokeless combustion of the
coal. The correct composition and the required uniformity of the mixture can be
attained outside the furnace only. The separation of the pure coal dust from
impurities should precede the preparation of the mixture.
To effect this separation I use the same air that is afterwards to be mixed with
the coal-dust; and in order to do this I introduce. the coal-dust mixed with
impurities into a current of air by which it is carried along for some distance, and
whilst being thus carried along the impurities and larger pieces fall down; as the
velocity of the air-current is so adjusted that practically only fine particles of
coal-dust can be carried by the current for the whole distance. The air and the
fine coal-lust then enter together into a chamber (hereinafter referred to as the
store-chamber) in which they are stored up as a finished mixture and are introduced
as required into the furnace. In this store-chamber the air is kept, in continuous
motion.
The air in the store-chamber will hold in suspension a percentage of coal-dust
that will vary in a regular manner with the velocity of-the-said-air-provided there
be sufficient coal-dust in the said store-chamber; so that even if the coal-dust be
introduced in excess into the store-chamber the air therein will hold in suspension
only the percentage of coal-dust that corresponds to the velocity with which it may
be moving. By altering the velocity of the air in the store-chamber, the
percentage composition of the mixture of air and coal-dust may therefore be
altered so as to correspond to the kind of coal employed. When a certain quantity
of air is fed from the store-chamber into the furnace there will be thus supplied
with it as large a quantity of coal-dust as the said quantity of air will be capable
of burning. A decrease or increase in the air supplied to the furnace will at
once cause a corresponding decrease or increase in the quantity of coal-dust supplied
with it, as the percentage composition of the mixture is always the same provided
the velocity of the air in the store-chamber remains unaltered. This percentage-
composition is altered only by a change in the velocity of the air in the store-
chamber and is independent of the quantity of air taken therefrom.
The diagrammatic drawing left with my Provisional Specification, shows, by
way of example only, an arrangement of apparatus suitable for carrying my
invention into effect. From a hopper A the coal-dust with its impurities is
conducted by means of a feed roller B or other suitable device into a current of
air, which may be produced by means of a fan C or by any other suitable apparatus.
This air-current carries the coal-dust through a passage Dinto the store-chamber F.
The velocity of the air whilst passing along the conduit D is so adjusted as to
allow anything suspended in it and heavier than the fine coal-dust. such as larger
pieces of coal and mineral admixtures, to fall down and be collected in a vessel E..
In the store-chamber F, the air arriving from the passage D and still holding
the coal-dust in suspension, is kept in motion by means of a fan G; the air in the
store-chamber F may however, be kept in motion by means of the fan C, or its
equivalent, only, or by any other suitable means. The velocity of the air is so
adjusted that it holds in suspension exactly as great a percentage of coal-dust as it
can burn in the most advantageous manner. When a larger quantity of coal-dust
is introduced into the store-chamber F then the air in motion therein is capable of
maintaining in suspension, the excess thereof falls down and is collected at the
bottom of the store-chamber, whence it is discharged from time to time into a
Fessel H placed underneath the said store-chamber. From the store-chamber F
the mixture of coal-dust and air is carried off through one or more passages J and

page_text: caused by means of a fan or its equivalent or by the natural draught to pass into
one or more furnaces. The arrangement of these furnaces may be of any known or
suitable kind, the combustion taking place, say on a grating of fire-bricks, against
which the mixture of coal-dust and air strikes ou igniting in entering the fireplace;
whilst in kindling the fire an ordinary grate or any other known or suitable
arrangement may be used.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
The herein described method of producing a mixture of coal-dust and air for
use as fuel in furnaces according to which the mixture of coal-dust and air is
compelled, before entering the fire place or furnace chamber, to pass through a
storage receptacle provided with means whereby a suitable motion can be imparted
to the air, to maintain the mixture of coal-dust and air uniformly of the
composition desired for the time being, substantially as described.
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For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.