IMPROVEMENTS IN STEAM BOILER AND OTHER FURNACES
Year: 1868

page_text: LETTERS PATENT to Francis Chamberlain, of Bredecot Court, near
Worcester, Engineer, for the Invention of "IMPROVEMENTS IN STEAM
BOILER AND OTHER FURNACES."
Sealed the 9th June 1868, and dated the 6th January 1868.
PROVISIONAL SPECIFICATION left by the said Francis Chamberlain
at the Office of the Commissioners of Patents, with his Petition,
on the 6th January 1868.
I, FRANCIS CHAMBERLAIN, of Bredecot Court, near Worcester,
Engineer, do hereby declare the nature of my said Invention for
"IMPROVEMENTS IN STEAM BOLLER AND OTHER FURNACES," to be as follows,
that is to say :-
This Invention relates to steam boiler and other furnaces, whereby a
more perfect combustion of the fuel and consequently prevention of
smoke is effected.
I construct my improved furnace on the exterior of the boiler. At
the front end of the top of the furnace I place a feeding hopper, which
extends into the interior of the furnace for the purpose of supplying
[Price 8d.]

page_text: the fuel continuously thereto, or if desired the fuel may be supplied
through the furnace door.
The fuel I prefer to employ is small coal, which on coming in contact
with the heated air in the furnace is instantly ignited, and the heated
products of combustion then pass over a large surface of incandescent
fuel (the residue of previously gasified coal) into a heat magazine
placed in the tube of the boiler for the purpose of generating steam or
other heating purposes. In order to facilitate the combustion of the
fuel I cause air to be admitted into the combustion chamber by means
of a regulating valve fitted at the hottest end of the furnace, such air
being heated in traversing, from the boiler end of the furnace to the
front or feeding end thereof, where it passes through perforations into.
the combustion chamber; the admission of cold air into the combustion
chamber tending to keep the arch or crown of the furnace cool, whilst at
the same time the air is heated before entering the combustion chamber.
When desired to increase the draught a jet of steam is admitted into
the gases and forces them on to the incandescent fuel. By this con-
struction of furnace fire-bars are dispensed with, and by constructing the
furnace outside the boiler a greater heating surface is obtained than
when the furnace is constructed within the tube of the boiler. The
heated products of combustion pass into an accumulator composed of
fire-clay built in the tube of the boiler, which accumulation is quickly
raised to a high temperature, the heated currents escaping through per-
forations direct against the plate of the boiler. An annular space is left
between the plates and the accumulator for the purpose of supporting
the draught. In places where space is limited a feeding hopper may be
placed in front of the boiler at the lower end, and in front of which
hopper is placed a vertical or nearly vertical grate supported above a
horizontal dead plate, a space being left between the bars and the dead
plate for the purpose of removing the waste residue from the fuel.
Air for supporting combustion passes through the vertical grate,
and through the incandescent fuel, the hopper being self-acting, and
heated products of combustion pass into an accumulator, as before
described with reference to the first arrangement. The vertical bars
may be arranged to tern on hinges to facilitate the cleaning out of the
dust from the accumulater.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Francis Chamberlain in the Great Seal Patent
Office on the 1st July 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANCIS
CHAMBERLAIN, of Bredecot Court, near Worcester, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of January, in the year of
our Lord One thousand eight hundred and sixty-eight, in the 31st year
of Her reign, did for Herself, Her heirs and successors, give and grant
unto me, the said Francis Chamberlain, her special license that I, the
said Francis Chamberlain, my executors, administrators, and assigns,
or such others as I, the said Francis Chamberlain, my executors,
administrators, or assigns, should at any time agree with, and no others,
from time to time and all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN STEAM
BOILERS AND OTHER FURNACES," upon the condition (amongst others) that
I, the said Francis Chamberlain, my executors or administrators, by
an instrument in writing under my hand and seal, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent. :
NOW KNOW YE, that I, the said Francis Chamberlain, do hereby
declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the
accompanying Drawings, and to the letters and figures marked thereon,
that is to say:-
My said Invention relates to improvements in steam boiler and other
furnaces, whereby a more perfect combustion of the fuel, and con-
sequently prevention of smoke is effected.
When applying my Invention to a steam generator, I construct the
improved furnace on the exterior of the boiler. At the front end of the

page_text: top of the furnace I place a feeding hopper, which extends into the
interior of the furnace for the purpose of supplying the fuel continuously
thereto; or if desired, the fuel may be supplied through the furnace door
The fuel I prefer to employ is small coal, which on coming in contact
with the heated air in the furnace is instantly ignited, and the heated
products of combustion then pass over a large surface of incandescent
fuel (the residue of previously gasified coal) into a heat magazine placed
in the tube of the boiler for the purpose of generating steam, or for other
heating purposes. In order to facilitate the combustion of the fuel I
cause air to be admitted into an air heating chamber or flue situate over
the combustion chamber by means of a regulating valve fitted at the
hottest end of such chamber, the air being heated in traversing from the
boiler end of the air heating chamber or flue to the front or feeding end
of the combustion chamber, where it passes through perforations into the
combustion chamber. The admission of cold air tends to keep the arch
or crown of the furnace cool, whilst at the same time the air is heated
before entering the combustion chamber. When desired to increase the
draught, a jet of steam is admitted into the gases and forces them into
the incandescent fuel. By this construction of furnace fire-bars are
dispensed with, and by constructing the furnace outside the boiler a
greater heating surface is obtained than when the furnace is constructed
within the tube of the boiler. The heated products of combustion pass
into a heat director or accumulator composed of fire-clay built in the
tube of the boiler, which accumulator is equally raised to a high
temperature, the heated currents escaping through perforations direct
against the plate of the boiler. A suitable space is left between the
plates and the accumulator for the purpose of supporting the draught.
In places where space is limited, a feeding hopper may be placed in front
of the boiler, and at the lower end of such hopper is placed a step grate,
or a vertical or nearly vertical grate supported above a horizontal dead
plate, a space being left between the bars and the dead plate for the
purpose of removing the waste or residue from the fuel. Air for
supporting combustion passes through the vertical grate and through the
incandescent fuel, the hopper being self-acting, and the heated products
of combustion pass into an accumulator, as before described with
reference to the first arrangement. The vertical bars may be arranged
to turn on hinges to facilitate the clearing out of the dust from the
accumulator,

page_text: And in order that iny said Invention may be fully understood, I shall
now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the annexed Sheet of Drawings, the
same letters of reference indicating corresponding parts in all the
corresponding Figures.
Figure 1 of the Drawings represents a longitudinal vertical section of
my improved furnace as applied to a Cornish boiler; Figure 2 is a
corresponding plan of the same showing the furnace in horizontal section
along the line 1-2 in Figure 1; Figure 3 is a transverse vertical section
of the furnace taken on the left-hand side of the Figure along the line
3-4-5-6, on the right-hand side along the line 7-8, in Figure 1,
and Figure 4 is a transverse vertical section of the boiler and heat
directors or accumulators taken along the line 9-10 in Figure 1.
A is the combustion chamber, which is constructed of ordinary brick-
work lined with fire-bricks, and is situate outside the front end of the
boiler. The fuel rests upon a solid bed or surface B of fire-brick, in lieu
of upon ordinary fire-bars, and the roof of the chamber is arched, as
shown at Figure 3; through this arched roof, and at or near the front end
of the combustion chamber are made a number of apertures a, a, com-
municating with the hot air chamber or zig-zag air flue C, constructed
immediately above the arched roof of the combustion chamber, the air
being admitted there to through a regulating valve D, situate at or near
the rear end of such chamber or flue, so as to be over the hottest part or
the combustion chamber A, the back end of the combustion chamber
opens direct into one or more heat directors or accumulators E, E¹, situate
inside the flue or flues F, F, of the boiler, such heat directors or
accumulators being so placed inside the flues as to leave an annular or
nearly annular space b, 61, between the exterior of each accumulator and
the interior of the flue in which it is placed, as shown clearly in
Figure 4. These heat directors or accumulators consist of long fire-clay
tube's closed at the rear end and perforated on their upper sides with
numerous small holes c, c, through which the gases from the fuel burn
in the form of jets in close proximity to the surface of the flues, as will
be clearly understood on referring to Figures 1 and 4 of the Drawings.
As the accumulators E, E', soon attain a highly elevated temperature,
and as they extend along the entire length or nearly so of the boiler
flues, it follows that a considerable amount of heat will be stored therein
and radiated uniformly to the surrounding sides of the flues, whilst at

page_text: the same time the numerous perforations in the accumulators serve as
directors of the flame jets, causing them to impinge equally against the
sides of the flues from end to end thereof.
The fuel employed consists of small coal, which is fed into the troughs
or hoppers G, and descends thence by its own gravity along the several
vertical passages d, d, into the front end of the combustion chamber A, a
regulator e being fitted, to each passage, if desired, for the purpose of
controlling or shutting off the supply of fuel to the furnace. In some
cases the fuel may be supplied in the ordinary manner through the open
fire-door H. The air for supporting combustion enters direct from .the
atmosphere into the air flue C, its ingress being controlled by the
regulating valve D. On turning the zig-zag flue or passage the air
becomes highly heated, and finally ente the front end of the com-
bustion chamber by the apertures a, a. 1 15 am jet pipe, which
inay be employed for directing a jet or jets of steal.. into the combustion
chamber when more than the ordinary draught is required.
products of combustion after having acted upon the boiler flue or flues
may return by external side flues, or be otherwise conducted to the
final outlet or chimney, according to the mode of setting the boiler
which I may here observe forms no part of my present Invention.
The
Figure 5 represents a sectional elevation of a portion of a Cornish
boiler, showing the arrangement of furnace which may be applied
thereto in cases where space is limited, and Figure, 6 is a corresponding
front elevation and transverse vertical section through, the line 1-2 in
Figure 5. In this modification the feeding hopper G is placed close against
the front of the boiler, and at the lower end and in front of this hopper
there is fitted a vertical or nearly vertical grate K, supported a little
above the dead plate L, the incandescent fuel which may be used of the
ordinary size, is principally contained between the grate and the boiler
front, a small portion being allowed to enter the flue or flues F. Instead
of the vertical bars a step grate may be used. Within these flues are
disposed heat directors or accumulators E constructed and operating in
precisely the same manner as herein-before described with reference to
Figures 1, 2, 3, and 4. In this arrangement the air for supporting
combustion enters the furnace through the vertical grating K.
Although I have only represented my said Invention as being applied
to steam boilers or generators, it is obviously applicable to other furnaces
for heating pürposes. - -

page_text: Having now described and particularly ascertained the nature of my
said Invention and the manner in which the same is or may be used or
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,
First. The combination of a fire-brick combustion chamber or furnace
with an air heating chamber or flue in communication therewith,
constructed above the arch of the said combustion chamber, and with a
perforated file-clay heat director or accumulator disposed in or under the
vessel to be heated, the whole being arranged and operating substantially
in the manner herein-before described.
Second. The combination of a feed hopper with a vertical or nearly
vertical or step grate and horizontal dead plate, situate outside a steam
generator or boiler with a fire-clay heat director or accumulator situate
in the flue or flues of such generator, substantially as herein-before
described and illustrated by Figures 5 and 6 of the Drawings.
In witness whereof, I, the said Francis Chamberlain, have to this
my Specification set my hand and seal, the 24th day of June One
thousand eight hundred and sixty-eight.
FRANCIS CHAMBERLAIN. (L.S.)