IMPROVEMENTS IN DOORS OR APPARATUS FOR REGULATING THE SUPPLY OF AIR TO STEAM BOILER AND OTHER FLUES AND FURNACES
Year: 1856

page_text: LETTERS PATENT to John Lee Stevens, of the City of London, Civil
Engineer, for the Invention of "IMPROVEMENTS IN DOORS OR APPARATUS
FOR REGULATING THE SUPPLY OF AIR TO STEAM BOILER AND OTHER FLUES AND
FURNACES."
Sealed the 29th July 1856, and dated the 30th January 1856.
PROVISIONAL SPECIFICATION left by the said John Lee Stevens at
the Office of the Commissioners of Patents, with his Petition, on the
30th January 1856.
I, JOHN LEE STEVENS, of the City of London, Civil Engineer, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN DOORS OR APPARATUS
FOR REGULATING THE SUPPLY OF AIR TO STEAM BOILER AND OTHER FLUES AND
FURNACES," to be as follows:-
This Invention consists of combining apparatus for the admission of atmo-
spheric air at the backs of steam boilers by perforated doors, which allow of the
supply of air being regulated proportionably with the more or less bituminous
nature of the coal, for the better ignition of the products of combustion, and
which doors may be adapted to other parts of steam boiler and other flues, and
to furnaces.
For this purpose, I make doorways opposite the tube or flue plates at the
backs of the boilers, and I fix thereto doors, each of which is constructed of

page_text: vertical plates, the inner ones of convex forms, and the outer and intermediate
plates of plane surfaces, all of which are perforated and so arranged that the
inner and outward plates are fixed in their respective positions, and that the
intermediate plates (being moveable) may be so adjusted as to determine or
regulate the quantity of atmospheric air passing in from the outer, and to be
distributed by the inner plates, as near as may be in accordance with the par-
ticular or immediate requirements of combustion, and so as to obtain the
utmost amount of heat from the ignition of the carbonaceous gases or other
products of combustion, instead of allowing them to pass wastefully away in
the form of smoke or otherwise; and where it is desirable, I adapt such air-
regulating doors to other parts of steam boiler and other flues and furnaces.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filetl
by the said John Lee Stevens in the Great Seal Patent Office on the
80th July 1856..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
LEE STEVENS, of the City of London, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, hearing date the Thirtieth day of January, in the year of our
Lord One thousand eight hundred and fifty-six, in the nineteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Lee Stevens, Her special licence that I, the said John Lee
Stevens, my executors, administrators, and assigns, or such others as I, the said
John Lee Stevens, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at 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
DOORS OR APPARATUS FOR REGULATING THE SUPPLY OF AIR TO STEAM BOILER AND
OTHER FLUES AND FURNACES," upon the condition (amongst others) that 1, the
said John Lee Stevens, my executors or administrators, by an instrument in
writing under my or their or one of their hands and seals, 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.

page_text: NOW KNOW YE, that I, the said John Lee Stevens, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:―
7
The Invention consists of combining apparatus for the admission of atmo-
spheric air at the back of steam boilers by perforated doors, which allow of the
supply of air being regulated proportionably with the more or less bituminous
nature of the coal for the better ignition of the products of combustion, and
which doors may be adapted to other parts of steam boiler and other flues and
furnaces.
For this purpose, I make doorways opposite the tube or' flue plates at the
backs of the boilers, and I fix' thereto doors, each of which is constructed of
vertical plates, the inner ones of a convex form; and the outer and intermediate
plates of plain surfaces, all of which are perforated; and: so' arranged that the
intermediate plates (being inoveable): may be:so adjusted as to determine and
regulate the quantity' of atmospheric air passing in from 'the outer, and to; be
distributed by the inner plates, as near as may be, in advance with the par-
ticular or immediate' requirements of combustion, and so as to obtain: the
utmost amount of heat from the ignition of the carbonaceous. gases or other
products of combustion, instead of allowing them to pass wastefully away in
the form of smoke or otherwise; and where it is desirable, I adapt such air-
regulating doors to other parts of steam boiler and other flues and furnaces.
It is not necessary that I should show how the doorways may be made in
the backs of steam boilers, or in any other parts thereof, or in flues or in
furnaces generally, as the same may bé constructed in the ordinary manner
known to boiler-makers and flue or furnace builders respectively, and I there-
fore proceed at once to describe what is requisite for the carrying out of my
Invention, reference being made to the accompanying Drawings.
Figures 1, 2, 3, 4, 5, and 6 include elevations and sections of the apparatus,
with corresponding letters of reference. a, a, the inner or convex plate, which
I prefer to be of a semi-globular form, but which may be elliptically or other-
wise curved, so as to comply with any particular requirement of the construc-
tion of the doorway, the other parts of the door being made to correspond
therewith; b, b, b, b, the outer plate, to which it will be seen the inner plate is
fixed, so that both may retain their respective or relative positions; c, c, c, c,
the intermediate or moveable plate; d, d, d, d, d, d, d, apertures for determining
or regulating the quantity of atmospheric air to be admitted; e, e, e, e, handles
fixed to the intermediate or moveable plate for the purpose of adjusting and
retaining the position thereof; f.fff, slots formed in the outer plate to admit

page_text: of the intermediate plate being moved up or down by the handles; g, g, screw
arrangement of the handles, by which, with a slight turning of the handles
upon their axes, they may be released from or fixed in any given position, the
bite or retaining pressure being on or against the outer plate.
By these Drawings and references it will be seen that the position of the
intermediate plate, adjusted by the means described, will determine and regu-
late the quantity of atmospheric air passing in from the outer and to be
distributed by the inner plate, as near as may be, in accordance with the par-
ticular requirements of combustion, and so as to obtain the utmost amount of
heat from the ignition of the carbonaceous gases, or other products of combus-
tion, instead of allowing them to pass wastefully away in the form of smoke or
otherwise. For instance, should the coal or other fuel be of a very bituminous
quality, or in other respects require a maximum supply of oxygen, a maximum
current of air can be admitted; or should the fuel in use be of the least bitu-
minous quality, or otherwise require only a minimum supply of oxygen, a
minimum current of air can be admitted, and between these two extremes the
supply may be modified to suit the existing requirement. It will be obvious
that the convexity of the inner plate (particularly if the semi-globular con-
figuration be retained) will better admit of the reciprocating action of expansion
and contraction caused by the greater or lesser heat from the fire, than if such
inner plate were made with plane surfaces, and will thereby be rendered much
.less liable to fracture.
And I claim as my Invention, the construction and application of doors or
apparatus for regulating the supply of air to steam boilers, flues, and furnaces,
in the manner herein-before described.
In witness whereof, I, the said John Lee Stevens, have hereunto set my
hand and seal, this Twenty-eighth day of July, in the year of our
Lord One thousand eight hundred and fifty-six.
Witness,
S. CARPMAEL.
J. LEE STEVENS. (L.S.)