AN IMPROVEMENT OR IMPROVEMENTS IN STEAM BOILERS
Year: 1854

page_text: LETTERS PATENT to John Mansfield, of Stoke, in the County of Stafford,
Engineer and Millwright, for the Invention of "AN IMPROVEMENT OR
IMPROVEMENTS IN STEAM BOILERS."
Sealed the 5th December 1854, and dated the 7th June 1854.
PROVISIONAL SPECIFICATION left by the said John Mansfield at the
Office of the Commissioners of Patents, with his Petition, on the 7th
June 1854.
I, JOUN MANSFIELD, of Stoke, in the County of Stafford, Engineer and
Millwright, do hereby declare the nature of the said Invention for "AN
IMPROVEMENT OR IMPROVEMENTS IN STEAM BOILERS" to be as follows:-
My. Invention consists in making the flue passing through a steam boiler,
and through which the flame and heated air pass, of a helical or corkscrew
form, that is to say, of a form somewhat resembling the worm of a still. By
making the flame and heated air pass through this tortuous channel they are
effectually deprived of their heat. My Invention is applicable both to vertical
and horizontal boilers. In applying it to the latter, I connect the chimney
end of the flue with the boiler by means of a pipe and stop-cock, by means
of which steam may be blown through the fluc, and the said flue thereby
cleansed. Instead of the ordinary fire doors, I close the front of the furnace
by means of a door, sliding vertically and counterbalanced, so that I can
determine with great nicety the quantity of air allowed to enter the furnace.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Mansfield in the Great Seal Patent Office on the
5th December 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JoпN
MANSFIELD, of Stoke, in the County of Stafford, Engineer and Millwright,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of June, in the year of our Lord One
thousand eight hundred and fifty-four, in the seventeenth year of IIer reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
John Mansfield, Her special licence that I, the said John Mansfield, my
executors, administrators, and assigns, or such others as I, the said John
Mansfield, 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 AN IMPROVEMENT OR IMPROVEMENTS
IN STEAM BOILERS," upon the condition (amongst others) that I, the said John
Mansfield, by an instrument in writing under my hand and seal, should parti-
cularly 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 John Mansfield, 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):—
My Invention consists in making the flue passing through a steam boiler,
and through which said flue the flame and heated air from the furnace pass, of
a helical or corkscrew-like form, that is to say, of a form somewhat resembling
the worm of a still. By making the flame and heated air of the furnace pass
through this tortuous channel they are effectually deprived of their heat. My
said Invention is applicable to vertical and horizontal boilers. In applying
it to the latter, I connect the chimney end of the flue with the boiler by
means of a pipe and a stop-cock; by these means the steam may be blown
through the flue, and the said flue thereby cleaned. Instead of the ordinary
fire door, I close the front of the furnace by means of a door, sliding vertically,
to the bottom of the ash-pit, the said door being hung from a chain passing

page_text: over a pulley and counterbalanced; by this arrangement I can determine
with great nicety the quantity of air allowed to enter the furnace. Although
I have only described a boiler having one flue, yet my Invention is applicable
to boilers having two or more flues.
Having now described the nature of my said Invention, and the manner of
carrying the same into effect, I wish it to be understood that I do not limit
myself to any particular details, as the same may be varied without departing
from the nature of my said Invention; for example, the diameter of the flue,
the metal or alloy of which it is made, and number of convolutions it makes
in passing through the boiler, must be varied, to suit the particular boiler to
which my Invention is applied. But I claim as my Invention, making the
flue or flues of steam boilers (through which said flue or flues the flame and
heated air from the furnace pass) of a helical or corkscrew-like form, as herein-
before described.
In witness whereof, I, the said John Mansfield, have hereunto set my
hand and seal, this Second day of December, in the year of our Lord
One thousand eight hundred and fifty-four.
Witness,
JOHN CLIFFORD ETCHES.
JOHN MANSFIELD. (L.s.)