IMPROVEMENTS IN THE CONSTRUCTION OF STEAM BOILERS
Year: 1869

page_text: LETTERS PATENT to Gilbert Hamilton, of the Firm of James Watt
and Company, of Soho Foundry, Smethwick, in the County of
Stafford, for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF
STEAM BOILERS."
Sealed the 20th May 1870, and dated the 31st December 1869.
PROVISIONAL SPECIFICATION left by the said Gilbert Hamilton at the
Office of the Commissioners of Patents, with his Petition, on the
81st December 1869.
I, GILBERT HAMILTON, of the Firm of James Watt and Company, of
Soho Foundry, Smethwick, in the County of Stafford, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN THE CONSTRUCTION
OF STEAM BOILERS," to be as follows:-
My Invention relates to boilers of the kind commonly called Cornish
boilers, that is, boilers having an internal flue or flues through which
the flame and heated air from the fire pass.
My Invention consists in constructing in the said flue a series of
pockets or water spaces extending from the body of the boiler into the

page_text: interior of the flue. The pockets are situated alternately on opposite
sides of the flue, and constitute a series of deflectors by which the flame
and heated air are made to take a zig-zag path in passing through the
flue. By being made to take the course described the flame is broken
against the said pockets and gives out its heat to the boiler more
thoroughly than when it takes a direct uninterrupted course through the
flue. I prefer to make each pocket project to about the middle of the flue,
and to make an angle of from thirty to forty degrees with a vertical plane
passing along the flue. The pockets on the opposite sides incline in
opposite directions, that is, the bottom of each pocket takes its rise at an
angle of about thirty degrees above the lowest point of the flue, and
inclining upwards crosses the axis of the flue and terminates at about
thirty degrees below the top of the flue on the opposite side. By this
arrangement a clear space is left at the bottom of the flue for the col-
lection and removal of soot and ashes, while at the upper part of the
flue where the flame and heated air principally pass the passage is of
the zig-zag figure already described owing to the crossing of the alternate
pockets at the top of the flue. I do not however limit myself to the
precise arrangement of the said pockets. The sides of the pockets may
be inclined to one another, that is, the said pockets may be made wedge
shape in section. The said pockets facilitate the circulation of the water
in the boiler and strengthen the flue and give to it an elasticity which
prevents the wear and tear incident to the expansion and contraction of
flues of the ordinary construction. The said pockets also largely
increase the heat absorbing surface of the boiler, and the steam
generated on the inner surfaces of the said pockets rises without
interruption through the water.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Gilbert Hamilton in the Great Seal Patent Office
on the 22nd June 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GILBERT
HAMILTON, of the Firm of James Watt and Company, of Soho Foundry,
Smethwick, in the County of Stafford, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirty-first day of December, in the

page_text: year of our Lord One thousand eight hundred and sixty-nine, in the
thirty-third year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Gilbert Hamilton, Her
special licence that I, the said Gilbert Hamilton, my executors,
administrators, and assigns, or such others as I, the said Gilbert
Hamilton, 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 "IM-
PROVEMENTS IN THE CONSTRUCTION OF STEAM BOILERS," upon the condition
(amongst others) that I, the said Gilbert Hamilton, 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.
NOW KNOW YE, that I, the said Gilbert Hamilton, 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 relates to boilers of the kind commonly called Cornish.
boilers, that is, boilers having an internal flue or internal flues through
which the flame and heated air from the fire pass.
My said Invention consists in constructing in the said flue (or flues)
a series of pockets or water spaces extending from the body of the boiler
into the interior of the flue. These pockets are situated alternately on
opposite sides of the flue, and constitute a series of deflectors by which
the flame and heated air are made to take a zig-zag path in passing
through the flue. By being made to take the course described the
flame is broken against the said pockets, and gives out its heat to the
boiler more thoroughly than when it takes a direct uninterrupted course
through the flue. I prefer to make each pocket project to about the
middle of the flue and to make an angle of about forty degrees with a
vertical plane passing along the flue. The pockets on the opposite
sides incline in opposite directions, that is, the bottom of each pocket
takes its rise at an angle of about forty degrees from the lowest point

page_text: of the flue, and inclining upwards crosses the axis of the flue, and
terminates at about forty degrees from the top of the flue on the opposite
side. By this arrangement a clear space is left at the bottom of the flue
for the collection and removal of soot and ashes, while at the upper part
of the flue where the flame and heated air principally pass the passage
is of the zig-zag figure already described owing to the crossing of the
alternate pockets at the top of the flue. I do not however limit myself
to the precise arrangement of the said pockets. I recommend that the
sides of the pockets be inclined to one another, that is, that the said
pockets be made wedge shape in section. The said pockets strengthen
the flue and give to it an elasticity which prevents the wear and tear
incident to the expansion and contraction of flues of the ordinary con-
struction. The said pockets also facilitate the circulation of the water
in the boiler and largely increase the heat absorbing surface of the
boiler, and the steam generated on the inner surfaces of the said pockets
rises without interruption through the water,
Having explained the nature of my Invention I will proceed to
describe with reference to the accompanying Drawings the manner in
which the same is to be performed,
Figure 1 represents in longitudinal vertical section; Figure 2 in plan
(partly in horizontal section); and Figure 3 in transverse vertical section
a Cornish steam boiler provided with a single internal flue constructed
according to my Invention. a is the internal flue of the boiler, and 6 is
the furnace of the same; c, c, are the pockets or water spaces extending
from the body of the boiler into the said internal flue a. The said
pockets c, c, are situated alternately on opposite sides of the flue a, and
constitute a series of deflectors by which the flame and heated air from
the furnace 6 are made to take the zig-zag or tortuous path indicated by
the arrows in passing through the said flue a.
By an examination of the transverse section Figure 3 it will be seen
that each pocket or water space o projects to or near to the middle of the
flue a, and makes an angle of about forty degrees with a vertical plane
passing along the said flue. It will also be seen by reference to Figure 3
that the pockets c, c on opposite sides of the flue incline in opposite
directions, the said pockets crossing one another at the top of the flue.
By this crossing of the pockets at the top only it will be seen that there
is a clear space left at the bottom of the flue for the collection and removal
of soot and ashes, while at the upper part of the flue where the flame and

page_text: heated air principally pass the passage has a zig-zag figure owing to the
crossing of the alternate pockets at the top of the flue.
In the Drawings the pockets are represented of a wedge shape in
cross section, but other sectional figures may be given to the said
pockets.
Figure 4 represents in longitudinal vertical section, Figure 5 in hori-
zontal section, and Figure 6 in transverse vertical section a Cornish
boiler provided with two internal flues containing pockets or water spaces
constructed according to my Invention. The flues in the said
Figures 4, 5, and 6 are marked a, a, the furnaces are marked b, b, and
the pockets or water spaces are marked c, c.
Having now described the nature of my Invention, and the manner
in which the same is to be performed, I wish it to be understood that I
do not limit myself to the precise details herein described and illustrated,
as the same may be varied without departing from the nature of my
Invention; but I claim as my Invention, the improvements in the con-
struction of steam boilers provided with an internal flue or internal flues
herein-before described and illustrated in the accompanying Drawings,
that is to say, applying to the said flue or flues a series of pockets or water
spaces or deflectors constructed and arranged substantially as and for the
purposes described and illustrated.
In witness whereof, I, the said Gilbert Hamilton, have hereunto
set my hand and seal, this Twentieth day of June, in the year of
our Lord One thousand eight hundred and seventy.
Witness,
RICHARD SKERRETT,
Clerk to George Shaw,
Birmingham.
GILBERT HAMILTON. (L.S.)