IMPROVEMENTS IN THE FURNACES OF LOCOMOTIVE AND OTHER STEAM BOILERS
Year: 1857

page_text: LETTERS PATENT to Franklin Prestage, of Westbury, in the County of
Wilts, Civil Engineer, for the Invention of "IMPROVEMENTS IN THE
DATT
Sealed the 9th April 1858, and dated the 12th October 1857.
PROVISIONAL SPECIFICATION left by the said Franklin Prestage at the
Office of the Commissioners of Patents, with his Petition, on the 12th
October 1857.
I, FRANKLIN PRESTAGE, of Westbury, in the County of Wilts, Civil En-
gineer, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE FURNACES OF LOCOMOTIVE AND OTHER STEAM BOILERS," to be as follows:-
This Invention has for its object to effect the combustion of smoke in the
furnaces of tubular steam boilers. For this purpose I make use of a per-
forated chamber formed of fire clay or other suitable material divided into
compartments and enclosing the furnace ends of the tubes. The gases, &c.
evolved by the combustion of the fuel pass through the perforations, and are
met by and mixed with currents of air which effect their combustion.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Franklin Prestage in the Great Seal Patent Office on the
12th April 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANKLIN
PRESTAGE, of Westbury, in the County of Wilts, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twelfth day of October, in the year of our Lord One
thousand eight hundred and fifty-seven, in the twenty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Franklin Prestage, Her special licence that I, the said Franklin Prestage,
my executors, administrators, and assigns, or such others as I, the said
Franklin Prestage, 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
THE FURNACES OF LOCOMOTIVE AND OTHER STEAM BOILERS," upon the condition
(amongst others) that I, the said Franklin Prestage, my executors or admi-
nistrators, 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.
NOW KNOW YE, that I, the said Franklin Prestage, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
This Invention has for its object to effect the combustion of smoke in
the furnaces of tubular steam boilers. For this purpose I make use of a
perforated chamber formed of fire clay or other suitable material,
divided into compartments, and enclosing the furnace ends of the tubes.
The gases, &c. evolved by the combustion of the fuel pass through the
perforations, and are met by and mixed with currents of air which effect
their combustion.
The manner in which I carry my said Invention into operation will be fully
understood on reference to the accompanying Sheet of Drawings, Fig. 1 of
which represents a longitudinal section of the furnace end of a locomotive

page_text: steam boiler having my improvements applied thereto; Fig. 2, a transverse
section of the same; and Fig. 3 a horizontal section through the line z of
Figs. 1 and 2. a represents the furnace or fire box; b, the fire door; c, the
fire bars; and d, the tubes leading from the furnace through the boiler in the
ordinary manner. The space or chamber e is divided off from the body of
the furnace by the chambered partition f (formed of fire clay) resting on the
arch 9. and formed in compartments or cells h. The hollow stays i opening
to the atmosphere pass through the water space j in the front of the fire box,
and communicate with passages k (formed between the compartments), which
passages are provided with branches opening into the compartments h, the
sides of which are perforated with holes n forming the communication between
the space e and the body of the furnace. The gases, &c. evolved by the
combustion of the fuel in the furnace pass through the perforations n, and
are met by and mixed with currents of air, which entering through the hollow
stays i pass upward by the passages k and issue from the openings of the
branch passages 7.
Figs. 4, 5, and 6 are respectively longitudinal, transverse, and horizontal
sections similar to the foregoing, but representing a slightly modified arrange-
ment in which the fire clay or other chambered partition is divided into a
greater number of compartments (h) for the purpose of ensuring a more
perfect and uniform admixture of the atmospheric air (issuing from the
branch passages or openings 2) with the gases, &c. given off by the com-
bustion of the fuel. The various parts in these Figures are marked with the
same letters of reference as the corresponding parts of Figs. 1, 2, and 3.
Figs. 7, 8, and 9 are similar views representing another modification of
my Invention, which being marked with the same letters as the foregoing
Figures will be readily understood on referring to the descriptions appertaining
thereto.
Figs. 10, 11, and 12 are also similar views to those already described, and
are correspondingly lettered. In this modification the perforations n are
made larger in size than those previously described, and are continued entirely
through the partition f; they thus serve the double purpose of the perfo-
rations n and the compartments h before described.
Having now described the nature of my said Invention, and in what manner
the same may be performed, I would have it understood that I do not confine
myself to the precise form or details represented so long as the distinguishing
features of my Invention are maintained; but that what I claim with
reference thereto is the use or employment of a perforated chambered partition

page_text: supplied with air, and enclosing the furnace ends of the tubes, as described,
for the purpose herein-before mentioned.
In witness whereof, I, the said Franklin Prestage, have hereunto set my
hand and seal, this Tenth day of April, in the year of our Lord One
thousand eight. hundred and fifty-eight.
Witness,
FRANCIS WISE,
108, Fleet Street, London.
FRANKLIN (L.S.) PRESTAGE.