IMPROVEMENTS IN THE CONSTRUCTION OF STEAM BOILERS
Year: 1863

page_text: LETTERS PATENT to Joseph Musgrave, of the Globe Works, Bolton, in
the County of Lancaster, Engineer, for the Invention of "IMPROVEMENTS
IN THE CONSTRUCTION OF STEAM BOILERS."
Sealed the 18th September 1863, and dated the 30th March 1863.
PROVISIONAL SPECIFICATION left by the said Joseph Musgrave at the
Office of the Commissioners of Patents, with his Petition, on the 30th
March 1863.
I, JOSEPH MUSGRAVE, of the Globe Works, Bolton, in the County of
Lancaster, Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF STEAM BOILERS," to be as follows:-
My Invention is applicable to steam boilers having two longitudinal flues
containing at one end the firo grates; these flues extend from one end of
the boiler to the other and impart the requisite strength to the ends, but they
are closed near the bridge at the firing end either by partitions of fire brick or
by plates of iron having a space between them for the circulation of water,
which enters through holes in the longitudinal flues. The products of com-
bustion, after passing over the bridges, descend through vertical flues which
connect the horizontal flues to the outer shell of the boiler, the products of
combustion then pass along a flue in the boiler seating to the end of the boiler,
where they enter the end of one of the longitudinal flues; they are then con-
veyed through a lateral passage into the other longitudinal flue and return to
the end of the boiler into a sido flue in the seating, which conveys them to tho

page_text: firing end of the boiler, under which they pass to another flue in communi-
cation with the chimney. I wish to remark that the products of combustion,
after passing over the bridges, may pass through side flues connecting the
longitudinal flues to the shell of the boiler, and that the longitudinal flues,
instead of being connected together by a lateral passage to convey the products
of combustion from one to the other, may be connected to a lateral flue or flues
passing through the outer shell of the boiler.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Joseph Musgrave in the Great Seal Patent Office on the
29th September 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
MUSGRAVE, of the Globe Works, Bolton, in the County of Lancaster, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of March, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-sixth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Joseph Musgrave, Her special license that I, the said Joseph
Musgrave, my executors, administrators, and assigns, or such others as I, the
said Joseph Musgrave, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times there-
after 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
CONSTRUCTION OF STEAM BOILERS," upon the condition (amongst others) that I,
the said Joseph Musgrave, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should par-
ticularly 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 Joseph Musgrave, 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 (that is to say):-
My Invention is applicable to steam boilers having two longitudinal flues

page_text: containing at one end the fire grates; these flues extend from one end of the
boiler to the other and impart the requisite strength to the ends, but they are
closed near the bridge at the firing end either by partitions of fire brick or
otherwise. The products of combustion descend through vertical flues into an
external horizontal flue, they then pass along external flues to the end of the
boiler, where they enter the end of the internal flues, from whence they
descend through vertical flues into an external flue which is in communication
with the chimney.
And in order that my Invention may be fully understood and readily carried
into operation I will proceed to describe the accompanying Sheet of Drawings,
reference being had to the figures, letters, and arrows marked thereon.
Fig. 1 is a longitudinal section of my improved boiler; Fig. 2 is a ground
plan, and Fig. 8 a transverse section through the firing flues of the same.
a is the outer cylindrical casing of the boiler; b, b, the two internal flues
extending from one end of the boiler to the other, thus imparting the requisite
strength to the ends c, c. The flues 6 are rather larger at the firing end than
at the other, to give space for the grates d, d, and bridges e, e. The flues b
are closed at about the centre of their length by the partitions f, made, by
preference, of fire bricks. The products of combustion passing over the
bridges e pass through the vertical flues g into the external longitudinal flue h,
which conveys them towards the firing end of the boiler, where the longi-
tudinal flue branches upwards and conveys the products of combustion into
the side flues i, which extend the whole length of the boiler, and deliver them
into the ends of the internal flues b, from which they descend through the
vertical flues into another external flue k, which is in connection with the
chimney.
Figs. 4, 5, and 6, are three views of a boiler constructed according to a
modification of my Invention. In these views the boiler is made with a
single flue 6 containing the fire-grated and bridge e. The products of com-
bustion, after passing over the bridge e, descend through the vertical flue g to
the horizontal external flue h, then into the side flues i, from whence they
return into the internal flue b, and again descend through the vertical flue; to
the external flue k, which communicates with the chimney.
In boilers of the ordinary construction with internal flues it is well known
that the expansion is very unequal, particularly when the steam is being raised
rapidly on starting; this unequal expansion is due to the upper surface of the
flues and the upper portion of the cylindrical shell of the boiler being
heated before the lower parts thereof, but in the boiler above described such
unequal expansion cannot tako place, as the upper and lower parts of the

page_text: boiler, both internally and externally, are heated equally at the same time,
thus establishing a complete circulation of the water in the boiler as soon as
the fires are ignited.
Having thus stated the nature of my Invention and described the manner
of performing the same, I declare that I claim as my improvements in the
construction of steam boilers the vertical flues marked g and j for conveying
the products of combustion from the internal to the external flues, and the
arrangement of the flues, as shewn and described.
In witness whereof, I, the said Joseph Musgrave, have hereto set my
hand and seal, this Twenty-sixth day of September, in the year of our
Lord One thousand eight hundred and sixty-three.