IMPROVEMENTS IN CONSUMING SMOKE AND IN APPARATUS EMPLOYED THEREFOR, WHICH APPARATUS IS ALSO APPLICABLE FOR OTHER PURPOSES
Year: 1876

page_text: LETTERS PATENT to James Mc Glashan, of Dundee, in the County of Forfar,
North Britain, for the Invention of "IMPROVEMENTS IN CONSUMING SMOKE AND
IN APPARATUS EMPLOYED THEREFOR, WHICH APPARATUS IS ALSO APPLICABLE
FOR OTHER PURPOSES."
Sealed the 28th March 1877, and dated the 13th October 1876.
PROVISIONAL SPECIFICATION left by the said James McGlashan at the
Office of the Commissioners of Patents on the 13th October 1876.
JAMES MC GLASHAN, of Dundee, in the County of Forfar, North Britain.
"IM-
PROVEMENTS IN CONSUMING SMOKE AND IN APPARATUS EMPLOYED THEREFOR, WHICH
APPARATUS IS ALSO APPLICABLE FOR OTHER PURPOSES."
This Invention which has for its object to lessen the emission of smoke from the
furnaces or fire-grates of steam or other boilers, and from furnaces or fire-grates
generally, consists in placing at the rear end of the fire-bars a back wall which
almost entirely fills the space between the fire-bars and the upper side of the flue,
through which the products of combustion pass off from the fire-grate. The back
wall which may be composed of iron, fire-clay, or other suitable refractory material,
is perforated with holes or channels leading into the flue, and preferably inclined
upwards and outwards, so as to project the flame as much as possible against the
heating surface of the boiler. With this arrangement the products of combustion
are first caused to strike against the heated surface of the back wall, and then to
pass in a state of division through the channels or holes, which are also heated, by
which means combustion or consumption of the smoke is considerably diminished.
In order to prevent the perforated back wall from being burned it is preferred to
place it a considerable distance in the flue beyond the fire-bars, the intervening
space being filled with dead plates. These dead plates which, together with the
back wall are carried on rods or bars extending longitudinally beyond the fire-grate,
may be utilized to bear the live coals whilst cleaning the furnace, thereby removing
the necessity of reducing the fire when cleaning to such an extent as has been
hitherto practised.
The perforated back wall besides serving the purpose set forth also retains in the
furnace much of the dust which enters the flue with other arrangements of furnaces
or fire-grates.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Mc Glashan in the Great Seal Patent Office on the 13th April
1877.
"IM-
JAMES MC GLASHAN, of Dundee, in the County of Forfar, North Britain.
PROVEMENTS IN CONSUMING SMOKE AND IN APPARATUS EMPLOYED THEREFOR, WHICH
APPARATUS IS ALSO APPLICABLE FOR OTHER PURPOSES."
My said Invention which has for its object to lesson the emission of smoke from
the furnaces or fire-grates of steam or other boilers, and from furnaces and fire-grates
generally, consists in placing at the rear end of the fire-bars a back wall almost
entirely filling the space between the fire-bars and the upper side of the flue through
which the products of combustion pass off from the fire-grate. This back wall
which may be composed of iron, fire-clay, or other suitable refractory material, is
perforated with holes or channels leading into the flue, and by means of this
arrangement the products of combustion are first caused to strike against the heated
surface of the back wall, and then to pass in a state of division through the channels
or holes, which are also heated; the combustion or consumption of smoke is thus
considerably increased.
And in order that my said Invention may be properly understood, I now proceed
more particularly to set forth the system, mode, or manner in or under which
the same is or may be used or practically carried into effect, reference being had to
the annexed Sheet of Drawings, and to the letters and figures marked thereon,
that is to say :-
On the Sheet of Drawings hereunto appended Figure 1 is a part longitudinal
section of a horizontal steam boiler, shewing the adaptation of my said Invention
to the furnace or fire-grate thereof; Figure 2 is a horizontal section of the same
portion of the boiler; whilst Figure 3 is in part an end elevation and in part a
transverse section thereof.
As seen by these Figures the bridge or back dyke usually placed in the flues of
boilers is removed, and in lieu thereof a back wall a which nearly fills the space
between the level of the furnace bars b and the upper side of the flue is substituted,
the said back wall being composed, as seen at Figures 1, 3, and 4, of one piece or
several pieces of iron, fire-clay, or other fire-resisting material, perforated with
holes to permit the products of combustion to pass from the furnace or fire-grate
into the flue, or it may be composed of perforated sections or layers, as seen at
Figures 5 and 6, and at Figures 8 and 9, or of a series of tubes held together by an
outer casing or rim, as seen at Figure 7, or of any modified form of such arrange-
ments. The holes or perforation in the back wall may be circular, oval, elliptical,
rectangular, triangular, or of any desired form in transverse section; and in
order that the draught through the furnace may not be interfered with the aggregate
area of such holes or perforations in each back wall is so adjusted as to equal or
approximately to equal the area of the open space formerly existing over the
bridges. The holes or passages may either pass through the back wall at right
angles to its breadth, as seen on the Drawings, or they may be inclined upwards and
outwards, so as to project the flame as much as possible against the heating surface
of the boiler, and also make the passage of the smoke through the channels less
easy, and thus more effectually consume it.
In order to prevent the perforated back wall a from being burned it is preferred
to place it a considerable distance in the flue beyond the fire-bars b, the intervening
space being filled with dead plates d composed of slabs of iron, fire-clay, or other
equivalent material, the said slabs being put in loosely enough to allow of expansion
without jambing against each other or against the sides of the flue, and injury to
the flue by such expansion is thereby prevented. The passage of cold air into the
furnace or flue through interstices or spaces about or around the dead plates dis
prevented by the brick wall e which forms the inner end of the ash-pit and cuts off
communication with the part of the flue beyond the fire-bars.

page_text: The dead plates & may be utilized to bear the live coals whilst the fireman is
cleaning the furnace, thereby removing the necessity of reducing the fire when
cleaning to such an extent as hitherto.
The back wall a and the dead plates d are carried in the flue on iron rods fixed
at one end to the fire-bar bearers, or resting on the bricks e forming the back of the
ash-pit, the said rods at their inner ends being bent so as to rest on the bottom of
the flue, as seen at f, Figures 1 and 3 of the Drawings.
When it is desired not to disturb existing fittings in the flues of boilers the back
wall a forming part of my said Invention is or may be supported as seen in detail
at Figures 5 and 6 of the Drawings. With this arrangement a stool g to carry the
wall is placed in the flue and the perforated wall built in layers or courses upon it.
The rods to support the dead plates d, when such are employed with this form of
back wall are or may be secured to the stool at their inner ends.
The perforated back walls besides serving the purpose herein-before set forth also
retain in the furnace much of the dust which enters the flue with other arrange-
ments of furnaces or fire-grates.
Having now described and particularly ascertained the nature of my said Inven-
tion, and the system, mode, or manner, in or under which the same is or may be used
or practically carried into effect, I would observe in conclusion that what I consider
to be novel and original and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent is, the apparatus consisting of the
perforated back wall a, constructed substantially as herein-before described with
reference to the several Figures on the accompanying Sheet of Drawings, and the
employment thereof either alone or in combination with one or more dead plates at
the rear or inner end of the furnaces or fire grates, or in the flues of steam and
other boilers, and in furnaces and fire-grates generally, as and for the purposes set
forth.
In witness whereof, I, the said James Mc Glashan, have hereunto set my hand
and seal, this Eleventh day of April, One thousand eight hundred and
seventy-seven.
JAMES MC GLASHAN. (L.S.)