Improvements in Connection with the Furnaces of Steam Generators and other Furnaces for Accelerating the Draught thereof and Consuming Smoke therefrom.
Year: 1888

page_text: Date of Application, 1st Feb., 1888
Complete Specification Left, 1st Nov., 1888
Complete Specification Accepted, 7th Dec., 1888
Improvements in Connection with the Furnaces of Steam Generators
and other Furnaces for Accelerating the Draught thereof and
Consuming Smoke therefrom.
1 JOHN MCLAREN of Midland Engine Works Leeds in the County of York
Engineer do hereby declare the nature of this Invention which has been communicated
to me from abroad by Marie Augustin Despeissis of Bartley Street St. Kilda
Melbourne in the Colony of Victoria Sugar Manufacturer to be as follows :—
The object of this Invention is to provide means in connection with the furnaces of
sieam generators and other furnaces for accelerating the draught thereof and con-
suming smoke therefrom. According to this Invention an ejector or current inducing
device is provided by which a portion of the products of combustion from the furnace
are drawn from the flue or chimney and are delivered back again into the chimney
or funnel with an accelerated speed induced by the ejector or like device. There may
be used a passage or pipe leading to the furnace so that the ejector or the like also
causes the products of combustion drawn off by it or a portion thereof to be delivered
into the furnace either under or above the fuel or the said products so drawn off or
part of them may be delivered into the atmosphere and where passages are provided
for more than one of these plans to be used in connection with the same furnace,
valves or dampers are provided so that each passage can be opened and closed as
desired. The ash pit is preferably closed and the furnace fed by a mechanical stoker
so that the admission of cold air above and below the fuel can be controlled or pre-
vented. The ejector may be supplied with steam or with compressed air or a fan or
blower can be used as the current inducing device. In the case of an ejector when
compressed air is used it is preferred to provide for heating it a receiver in the flue
beyond the steam boiler and to draw therefrom by means of a pipe provided with a
valve any additional heated air required to effect complete combustion. When com-
pressed air is not used such a receiver is provided but at one end it is in communication
with the atmosphere and at the other end with the ash pit in order to heat the air
which is drawn by the ejector or the like. In all cases a valve or damper enables the

page_text: admittance of air into the furnace to be regulated... A'steain jet may be provided for
effecting the removal of soot from the suction pipe and chamber of the ejector.
There may be introduced into the combustion chamber at the back end of the flue
arched bridges or shelves one higher than the 'other the lower one being preferably
perforated and projecting from the inner wall and extending partly across to the outer
wall preferably in a plane just below the lowest tube of the boiler and the other or
upper bridge or shelf (which is solid) projecting from the outer wall and reaching
partly across towards the steam boiler so as to overlap the other bridge or shelf.
The latter bridge or shelf may be dispensed with if desired or there may be more
than two. Or there may be introduced into the flue a series of close partitions
with small space between the boiler or top of the flue and the tops of the partitions.
The partitions have openings or passages past them alternately placed in opposite
positions so that alternate apertures correspond on the same side of the flue. Or
there may be introduced into the flue a number of arches alternately at a higher and
a lower level that is to say the first, third (and so on) are at a level different from
that of the second, fourth (and so on). The arrangements described are designed to
give a circuitous or serpentine path to the products of combustion or such a path as
to cause them to come into close contact with heated surfaces. As a good draught
is required when these arrangements are used the device hereinbefore described
or its equivalent will be found useful in combination with such arrangements.
Dated this 1st day of February 1888
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C.,
Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Connection with the Furnaces of Steam Generators
and other Furnaces for Accelerating the Draught thereof and
Consuming Smoke therefrom.
1, JOHN MCLAREN of Midland Engine Works, Leeds in the County of York,
Engineer, do hereby declare the nature of this Invention (which has been communicated
to me from abroad by Marie Augustin Despeissis of Bartley Street, St. Kilda
Melbourne in the Colony of Victoria Sugar Manufacturer) and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :-
The object of this Invention is to provide means in connection with the furnaces of
steam generators and other furnaces for accelerating the draught thereof and con-
suming smoke therefrom. According to this Invention which I will describe with
reference to the accompanying drawings an ejector or current inducing device A
Figures 1, 2 and 3 is provided in a casing A2 by which the products of combustion
from the furnace or a portion thereof are or is drawn by the pipe or passage B² from
the flue funnel or chimney B and are delivered back again thereinto (as in
Figures 2 and 3) by the pipe or passage B³ with an accelerated speed induced by the
ejector or like device. There may be used a passage or pipe leading to the furnace
as at C Figure 3 (where it is shown in conjunction with the pipe or passage B³
although the pipe or passage C may be used without that 133, so that the ejector or
the like also causes the products of combustion drawn off by it or a portion thereof
to be delivered into the furnace either under or above the fuel or the said products so
drawn off or part of them may be delivered into the atmosphere (as at Figure 1) and
where passages are provided for more than one of these plans to be used in connection
with the same furnace valves or dampers are provided so that each passage can be
opened and closed as desired. This is shown with regard to the tubes or passages B³
and C in Figure 3 where the valve or damper is marked D, and it will be understood
that there may also be combined therewith a discharge opening into the atmosphere
that is to say either of the plans of discharge into the air, back into the flue chimney
or funnel and into the furnace may be used separately or any two of them or all
three of theu combined. The ash pit is preferably closed and the furnace fed by
a mechanical stoker so that the admission of cold air above and below the fuel can
be controlled or prevented. The ejector may be supplied with steam or compressed
air may be used for the purposes aforesaid and for creating a draught in the
chimney or funnel. In the case of an ejector when compressed air is used it is
preferred to provide for heating the air a receiver in the flue beyond the steam
boiler and by means of a pipe provided with a valve to draw therefrom any additional
heated air required to effect complete combustion. When compressed air is not
used such a receiver is provided but at one end it is in communication with the
atmosphere and at the other end with the ash pit in order to heat the air which is
drawn by the ejector or the like.
A valve or damper enables the admittance of air into the furnace to be regulated.

page_text: A steam jet may be provided for effecting the removal of soot from the suction pipe
and chamber of the ejector.
Should the combustion be good i.e. presuming the products of combustion to have
previously been well mixed, at a high temperature with oxygen so that the com-
bustion is practically complete it will not be necessary to return any of the products
of combustion to the furnace.
As an additional means of consuming the smoke from furnaces there are placed
in the combustion chamber as shown in sections at right angles to each other in
Figures 4 and 5 of the accompanying drawings at the back end of the steam boiler,
two arched bridges or shelves E and F of any suitable shape one in a higher position
than the other. The lower one E projects from the inner wall and extends partly
across towards the opposite wall the upper one F projecting from the outer wall and
reaching partly across towards the other side as shown in Figure 4 so as to overlap
the lower one E. The upper arch bridge or shelf F is made solid, but the lower one E
it is preferred to perforate or form with apertures of any suitable size. The lower
arch bridge E it is preferred to place just below the level of the lowest tubes of the
boiler. The upper arch bridge F may be dispensed with if preferred and the arch E
be used alone. In order to increase the heating surface of the arched bridges or
shelves E and F the outward ends thereof may be notched. The apertures and holes
give a very extensive heating surface and have besides somewhat the effect of a
Bunsen burner. By this arrangement the products of combustion are divided and
are in close contact with highly heated material through a very extensive course.
If desired there may be more than two arched bridges or shelves overlapping each
other and leaving sufficient flue area between them..
The arrangement shown in Figures 4, 5 may be placed in the fire box, in which
case the lower arch bridge must be perforated or have apertures made therein.
Figure 6 shews in vertical longitudinal section an arrangement of two or a series
of shelves or arch bridges, projecting from the front of the fire box of a locomotive
boiler and extending partly across towards the boiler. The lower one is perforated
or formed with apertures which divide the products of combustion: the overplus of
which has to escape through the space between the ends of the arch bridges and the
boiler. The object of this construction is morcover to cause the said products
to be in close contact with heated material and to pass readily into the lowest
tubes.
:
As an additional or alternative means for consuming the smoke from the steam
boiler there are introduced into the flue (as shown in Figures 7 and 8 in plan and
end section respectively) from the furnace to the combustion chamber, a series of
transverse partitions G with small spaces g between the tops thereof and the boiler.
These partitions are closed at one side of the flue but leave a space g at the other
side of suitable size to carry off the products of combustion which cannot escape
over the top of each partition. The partitions are so arranged relatively to each
other that the said spaces ² are alternately at opposite sides so as to obstruct the
current and prevent it continuing in a straight line on the same side of the flue,
whereby the products of combustion are brought into close contact with heated
material through an extended course so as to render efficient the heating surface
formed as aforesaid.
As another alternative means of consuming the smoke from steam boilers as shown
in sections at right angles to each other in Figures 9 and 10 instead of the last
preceding arrangement, there is introduced into the fluc, at the most convenient.
points from the furnace to the combustion chamber, a series of transverse arched
bridges or shelves G2 apart from each other. It is preferred that the distance from
--the-boiler-to-the-top of the first. arched. bridge.or.shelf, of the third one_and_so_on
shall be about nine inches and the distance from the steam boiler to the top of
the second arched bridge or shelf of the fourth one and so on about four inches
the said arched bridges or shelves being of any desired thickness. The products
of combustion thus passing by a circuitous course in close contact with the heated
material so arranged are ignited and have time to give up their heat.

page_text: The same result as that obtained with partitions, arched bridges or shelves, may be
obtained by introducing into the flue from the furnace to the back of the boiler, a
series of intervening pillars with tops either close to, or at a short distance from,
the steam boiler, leaving between them sufficient flue area to carry off the products
of combustion.
The arched bridges, shelves, partitions and pillars require good draught to admit
into the furnace the amount of air necessary for complete combustion. By consuming
the smoke, the products are rarified, thus increasing the draught and the device
hereinbefore described with reference to Figures 1, 2 and 3 or its equivalent will be
found useful in combination with the arrangements Figures 1 to 10.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is :-
1. In connection with furnaces for the purposes described means for drawing off by
means of a jet blast (worked by steam or compressed air) products of combustion
from the chimney funnel or flue and returning them again thereto, or delivering
them to the furnace, or into the outer air, or any two, or all, of them in combination
substantially as described and illustrated in figures 1, 2 and 3 of the accompanying
drawings.
2. In connection with furnaces means for ejecting a jet of compressed air into the
funnel chimney or discharge flue substantially as hereinbefore described.
3. In the combustion chamber or fire box of a locomotive or other furnace an
arched bridge or shelf or several such bridges or shelves with the lower one or both
or all of them either solid or perforated or apertured substantially as and for the
purposes hereinbefore described and illustrated by Figures 4. 5 and 6 of the
accompanying drawings.
4. In the flue leading from a furnace to a combustion chamber a series of bridges
or walls arranged substantially as and for the purpose herein before described and
as illustrated by Figures 7 and 8 and Figures 9 and 10 of the accompanying
drawings.
5. In the flue leading from the furnace to the back of a boiler pillars arranged
substantially as and for the purposes hereinbefore described.
6. The combination as a whole of the apparatus Figures 1, 2 or 3 with either one
or more of the arrangements Figures 4 to 10 of the accompanying drawings.
Dated this 1st day of November 1888.