Improvements relating to the Production of Artincial Draugnt în Steam-boiler and other Furnaces and to Apparatus therefor.
Year: 1887

page_text: Date of Application, 19th Sept., 1887
Complete Specification Left, 13th July, 1888
Complete Specification Accepted, 17th Aug., 1888
Improvements relating to the Production of Artincial Draugnt în
Steam-boiler and other Furnaces and to Apparatus therefor.
We, HENRY FRANCIS GREEN, of 91 Queen Victoria Street, in the City of London,
Engineer, and GEORGE WILLIAM NEWALL of 14 First Avenue, Manor Park, in the
County of Essex, Engineer, do hereby declare the nature of this invention to be as
follows:-
The main object of our invention is to provide improved means for producing
artificial draught in the furnaces of steam boilers or generators. Our improvements
are, however, applicable to other furnaces.
Various methods have hitherto been adopted for increasing the draught in furnaces.
In some instances, the exhaust steam from a steam-engine or the live steam from a
boiler has been used to produce a blast in the chimney, shaft or funnel; in other
instances, air has been injected into the furnace either above or below the grate at
different points throughout the length of the furnace.
The use of steam for the purpose above mentioned is disadvantageous for the
following reasons, amongst others, viz. :-The steam is apt to condense upon the
interior of the funnel and thus deteriorate the metal thereof and cause or increase
the deposit of soot thorcon; moreover the steam, by reason of its condensation as it
issues from the blast-pipe or nozzle, will not act upon the air in the funnel except at
inconsiderable distances from the said blast-pipe or nozzle; the scum and muddy
deposits from the boiler are liable to be blown out with the steam; and high pressures
must be used in order to obtain the required draught. In marine boilers, the use
of a steam-blast is very undesirable by reason of the loss of fresh water thereby
occasioned, and the consequent necessity for introducing sea-water into the boilers to
replace the fresh water thus extracted.
The introduction of air into the furnace above or below the grate does not produce
the best practical results, because it necessarily occasions more or less compression of
the air in the flues and chimney or funnel. Moreover, when a jet of cold air is
introduced into the furnace above the grate, it cools the plates of the furnace and is
liable to injure the same by causing unequal expansion of the metal.

page_text: Now according to our present invention, we provide for the introduction of air into
the chimney or funnel or into the smoke-box or up-take in such a manner as to
induce a current of air through the fire-grate and flues, that is to say, we provide for
drawing the air by induction out of the furnace, so that the external atmosphere will
rush through the spaces between the fire-bars, or through other apertures provided
for the purpose, into the said furnace, and will promote the combustion of the fuel and
gases therein.
In carrying our present invention into practice, we employ a blast-pipe or other
suitable device connected with an air-compressor or with a reservoir for containing
compressed air or with a fan or blower or other means for supplying air under
pressure and we arrange the said blast-pipe or other device in the smoke-box or in
the uptake or in the funnel or chimney. We are thus enabled, by the use of a jet or
current of air at a comparatively low pressure to draw a very large quantity of air
through the furnace and thus greatly increase or intensify the combustion taking
place therein and prevent or diminish the discharge of smoke from the chimney or
funnel. Moreover the jet or current of air, not being condensed like the steam,
expands and acts upon the air in the chimney or funnel or in the uptake or smoke-
box throughout the entire transverse area thereof, and, instead of increasing or
promoting the deposition of soot on the interior thereof, the jet or current of air
assists in carrying the soot out of the same.
We sometimes employ a tube fixed in the uptake or in the chimney or funnel and
having a blast-pipe or equivalent device arranged within it so that the jet or current
of air from the blast-pipe or the like will induce a current of air in the said tube.
This is advantageous in cases where the funnel or uptake is of large area.
We find it advantageous to use fire-doors constructed as follows that is to say, the
door is cast with projecting nozzles thereon which extend into the furnace. "Firo
clay or other refractory material is used to fill the spaces between these nozzles, and
a sliding plate is provided for closing the apertures in the door. The air by these
means is divided into a number of jets and is kept cool until it reaches the heated
fuel so that its expansion will not impede the flow of air through the said nozzles.
The air is moreover introduced immediately above the heated fuel in the furnace, and
the door is kept cool so that it can be easily handled.
By our invention we are enabled to effect great economy with respect to the con-
sumption of fuel. Morcover, in the case of marine boilers, our invention affords the
great advantage over the steam-blast that the steam used for compressing the air can
be admitted into a condenser instead of being permitted to escape into the
atmosphere.
Dotad this 10th dover of Santamba- 1007
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicants.

page_text: Improvements relating to the Production of Artificial Draught in
Steam-boiler and other Furnaces and to Apparatus therefor.
We, HENRY FRANCIS GREEN of 91 Queen Victoria Street, in the City of London,
Engineer and GEORGE WILLIAM NEWALL of 14 First Avenue, Manor Park in the
County of Essex, 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:-
The main object of our invention is to provide improved means for producing
artificial draught in the furnaces of steam-boilers or generators. Our improvements
are, however, applicable to other furnaces.
Various methods have hitherto been adopted for increasing the draught in furnaces.
In some instances, the exhaust steam from a steam-engine or the live steam from a
boiler has been used to produce a blast in the chimney, shaft or funnel; in other
instances, air has been injected into the furnace either above or below the grate at
different points throughout the length of the furnace.
The use of steam for the purpose above mentioned is disadvantageous for the
following reasons, amongst others, viz. The steam is apt to condense upon the
interior of the funnel and thus deteriorate the metal thereof and cause or increase
the deposit of soot thereon; the steam, by reason of its condensation as it issues from the
blast-pipe or nozzle, will not act upon the air in the funnel except at inconsiderable
distances from the said pipe or nozzle; the scum and muddy deposits from the boiler
are liable to be blown out with the steam; moreover high pressures must be used in
order to obtain the required draught. In marine boilers the use of a steam-blast is
very undesirable by reason of the loss of frosh water thereby occasioned, and the
consequent necessity for introducing sea-water into the boilers to replace the fresh
water thus extracted.
The introduction of air into the furnace above or below the grate does not produce
the best practical results, because it necessarily occasions more or less compression of
the air in the flues and chimney or funnel. Moreover, when a jet of cold air is intro-
duced into the furnace above the graie, it cools the plates of the furnace and is liable
to injure the same by causing unequal expansion of the metal.
Now, according to our present invention we provide for the introduction of air into
the chimney or funnel or into the sinoke-box or up-take in such a manner as to induce
a current of air through the fire-grate and flues, that is to say, we provide for drawing
the air by induction out of the furnace so that the external atmosphere will rush through
the spaces between the fire-bars, or through other apertures provided for the purpose,
into the said furnace, and will promote the combustion of the fuel and gases
therein.
Our said invention, moreover, comprises an improved fire-door, whereby we provide
for the admission of air into the furnace above the fuel in an advantageous
manner.
In the accompanying drawings we have shown how our said invention may be con-
veniently and advantageously applied to a marine boiler.
Figure 1 is a front elevation of the said boiler with our improvements applied
thereto part of the smoke-box casing and other parts being removed.

page_text: Figure 2 is a side elevation of the said boiler, the smoke box casing, the funnel and
other parts being shown in vertical central section.
Figure 3 is a horizontal section on the line a, a Figure 2.
Figuro 4 is a front elevation, and
Figure 5 a section on the line y, y Figure 4 showing the improved furnace-door
hereinafter described.
Like letters indicate corresponding parts throughout the drawings.
A is the boiler; B the smoke box; C the uptake; D the funnel or chimney;
E, E are the furnace or fire doors; F is an air compressor for the purpose hereinafter
specified.
The
a is a blast-pipe provided with nozzles b, b. The blast-pipe a is connected by means
of a pipe a with a reservoir or chamber c for containing compressed air.
reservoir c is connected by a pipe c with the air compressor F, or with a fan
or blower or other means for supplying air under pressure. The blast-pipe a and
nozzles bare placed in the uptake C. In some cases the said blast-pipe and nozzle
may be placed in the smoke box B or in the funnel or chimney D. The pipe a¹ is
provided with a stop cock or stop valve d having a rod or extension d¹ and a handle d
for opening and closing the said cock or valve. By means of the stop-cock or stop-
valve d the compressed air can be shut off when the fire door is opened for firing, and
the pressure of air discharged through the nozzles & can be regulated at will by the
fireman. The reservoir or air chamber c is moreover provided with an adjustable relief
valve or safety valve e, for regulating the pressure in the said reservoir. is a division
plate fixed in the smoke box B and uptake C so that the action of the nozzles b, b may be
separated and the air may not be impeded in its upward course by the amalgamation
of the two currents. g, g are dampers or regulating plates attached by means of hinges h
to the shell of the boiler A. The dampers or regulating plates g are moreover pro-
vided with levers i pivoted at i¹ to the said dampers or regulating plates 9 and passing
through holes j in the wall of the uptake C for that purpose. The levers have
notches adapted to engage with catches j fixed to the uptake C. The levers i are
moreover provided with counterbalance weights 2³. By means of the dampers or
regulating plates g, the space in the uptake C for the induced draught can be adjusted,
or the said dampers or regulating plates can be raised or turned back so as to open the
passage through the said uptake to its full area when the fire-doors are closed and the
natural draught is being employed.
By our invention we are enabled by the use of a jet or current of air at a com-
paratively low pressure to draw a very large quantity of air through the furnace and
thus greatly increase or intensify the combustion taking place therein and prevent or
diminish the discharge of smoke from the chimney or funnel D. Moreover the jet
or current of air, not being condensed like steam, expands and acts upon the air in
the chimney or funnel or in the uptake or smoke-box throughout the entire transverse
area thereof, and instead of increasing or promoting the deposition of soot on the
interior thereof, the jet or current of air assists in carrying the soot out of the same.
In some cases we hinge or joint the blast pipe a carrying the nozzles b, to the pipe a
in such a manner that the said nozzles and pipe a can be swung back and removed
from the uptake C when not in use through a suitable sliding or other door provided
in the wall of the uptake for that purpose.
We sometimes moreover employ a tube fixed in the uptake or in the chimney or
funnel, and having a blast-pipe or equivalent device arranged within it so that the jet
or current of air from the blast-pipe or the like will induce a current of air in the said
tube. This is advantageous in cases where the funnel or uptake is of large area.
said tube may be conical or of any other convenient form.
The
We find it advantageous to use fire-doors constructed as follows that is to say, the
door E is cast with projecting nozzles which extend into the furnace. The spaces /
between these nozzles are filled with fire clay or other refractory material and a plate m
having slots mand arranged to slide in grooves m² is provided for closing or partially
closing the apertures n of the nozzles k. The plate m may be slid to and fro by
means of the latches m³ used for opening and closing the fire-door E. The air passes

page_text: into the furnace through the apertures n and is divided into a number of jets and is
kept cool until it reaches the heated fuel so that its expansion will not impede the flow
of air through the said nozzles k. The air is moreover introduced immediately above
the heated fuel in the furnace and the door is kept cool so that it can be easily
handled.
By our invention we are enabled to effect great economy with respect to the con-
sumption of fuel. Moreover in the case of marine boilers, our invention affords the
great advantage over the steam-blast, that the steam used for compressing the
air can be conducted into a condenser instead of being permitted to escape into
the atmosphere.
Although we have hereinbefore more particularly described our invention as applied
to a marine boiler, it is obvious that it is also applicable to boilers or furnaces of any
description.
Moreover we can further modify the construction of our apparatus without
departing from the nature of our said invention. For instance, we may connect the air
compressor, fan or equivalent device directly to the blast pipe and delivery nozzles
without the intervention of the reservoir or air-chamber hereinbeforo described.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we wish it understood that
we claim :-
First. The production of artificial draught in a steam-boiler or other furnace by
the introduction of compressed air into the smoke-box, uptake, funnel or chimney, as,
and for the purpose, above specified.
Second. The combination of an air-compressor, a fan or blower or equivalent device,
a blast-pipe connected therewith and provided with one or more discharge nozzles and
with a stop cock or valve, with or without a reservoir or chamber for the compressed
air, all substantially as, and for the purposes, set forth.
Third. In combination with apparatus for the introduction of compressed air into
the sinoke-box or uptake of a steam-boiler, the plate or partition for dividing or
separating the said smoke-box and uptake into two compartments, substantially as,
and for the purposes, specified.
Fourth. The combination, with a nozzle for the introduction of compressed air into
a smoke-box, uptake, funnel or chimmey, of a conical or other tube surrounding the
said nozzle, substantially as, and for the purpose, set forth.
Fifth. The hinged dampers or regulating plates, provided with pivoted levers
having notches, counterweights and catches, substantially as, and for the purposes,
set forth.
Sixth. The improved furnace-door or fire-door having the nozzles with or without
refractory material in the spaces between the same and the sliding plate provided
with suitable slots or apertures, substantially as, and for the purpose, set forth.
Seventh. The marine boiler provided with our improved apparatus consisting of
the parts constructed and combined substantially as described with reference to the
accompanying drawings and operating as, and for the purpose, specified.
Dated this 15th day of July 1800.
HENRY FRANCIS GREEN.
GEORGE WILLIAM NEWALL.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicants."