IMPROVEMENTS IN STEAM BOILERS
Year: 1875

page_text: LETTERS PATENT to John Alison, of No. 90, Lancaster Gate, in the
County of Middlesex, for the Invention of "IMPROVEMENTS IN STEAM
BOILERS."
Sealed the 15th May 1875, and dated the 15th March 1875.
PROVISIONAL SPECIFICATION left by the said John Alison at the
Office of the Commissioners of Patents, with his Petition, on the
15th March 1874.
I, JOHN ALISON, of No. 90, Lancaster Gate, in the County of Middle-
sex, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN STEAM BOILERS," to be as follows:-
This Invention has for its object improvements in steam boilers.
The outer shell of the boiler is cylindrical; it stands in an upright
position, and has a flattened dome top.
The fire-box is arranged at the lower part; it is also cylindrical, and
is similarly closed at the top. In the annular water space between the
shell and the fire-box there is a cylindrical diaphragm to direct the cir-
culation of the water,

page_text: Curved water tubes are arranged in the upper part of the fire-box.
Each tube is inserted at one end into the side of the fire-box and at the
other into the crown or domed top.
it
The boiler flue is a single tube springing from the top of the fire-box;
passes out through the upper dome or top of the boiler by a stuffing 5
box, and is secured by a nut screwed on it and down on the top of boiler,
so that the flue acts as a stay between the boiler and fire-box. The
stuffing box is packed with asbestos or other packing capable or sustaining
a high temperature.
The outer shell of the boiler is in two lengths, connected by flanges 1
and screw bolts, so that when the interior of the boiler requires exami-
nation it is readily taken apart.
The steam is drawn for use from an annular steam chest fixed within
the boiler at the upper part. The steam enters the chest by apertures
in the top, and the steam pipe is placed at one side, and turned up so as 1
to take the steam from near the top side of steam chest where there are
no openings in the top, so that steam cannot enter the pipe directly.
These arrangements are made to prevent priming, and any water which
may be carried with the steam into the steam chest is there deposited.
It drains to one side, and is conducted by a drain pipe to the outer side s
of the diaphragm surrounding the fire-box.
This boiler is an improvement on that described in the Specification of
a former Patent granted to me, No. 516, in the year 1867.
I employ a safety valve having a conc on the under side. The object
of this conc is to diminish as much as possible the area of that part of
the valve subject to the influence of the issuing steam, and consequently
to increase the total pressure on the valve, causing it to lift higher than
it would otherwise do, and to continue to rise higher as the pressure in
the boiler increases.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 3
filed by the said John Alison in the Great Seal Patent Office on
the 15th May 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JoпN
ALISON, of No. 90, Lancaster Gate, in the County of Middlesex, send
greeting.
3

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifteenth day of March, in the
year of our Lord One thousand eight. hundred and seventy-five, in
the thirty-eighth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said John Alison, Her special
license that I, the said John Alison, my executors, administrators, and
assigns, or such others as I, the said John Alison, my executors, admi-
nistrators, 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 STEAM
BOILERS," upon the condition (amongst others) that I, the said John
Alison, 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 John Alison, 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 :-
This Invention has for its object improvements in steam boilers.
The outer shell of the boiler is cylindrical; it stands in an upright
position, and has a flattened dome top.
The fire-box is arranged at the lower part; it is also cylindrical, and
is similarly closed at the top. In the annular water space between the
shell and the fire-box there is a cylindrical diaphragm to direct the cir-
culation of the water.
Curved water tubes are arranged in the upper part of the fire-box.
Each tube is inserted at one end into the side of the fire-box and at the
other into the crown or domed top.
The boiler flue is a single tube springing from the top of the fire-box;
it passes out through the upper dome or top of the boiler by a stuffing
box, and is secured by a nut screwed on it and down on the top of the

page_text: boiler, so that the flue acts as a stay between the boiler and the fire-box.
The stuffing box is packed with asbestos or other packing capable of
sustaining a high temperature:
The outer shell of the boiler is in two lengths connected by flanges
and screw bolts, so that when the interior of the boiler requires exami-
nation it is readily taken apart.
The steam is drawn for use from an annular steam chest fixed within
the boiler at the upper part. The steam enters the chest by apertures in
the top, and the steam pipe is placed at one side and turned up so as to
take the steam from near the top side of steam chest where there are no
openings in the top, so that steam cannot enter the pipe directly. These
arrangements are made to prevent priming, and any water which may be
carried with the steam into the steam chest is there deposited. It drains
to one side, and is conducted by a drain pipe to the outer side of the
diaphragm surrounding the fire-box.
This boiler is an improvement on that described in the Specification of
a former Patent granted to me, No. 510 in the year 1867.
I employ a safety valve having a conc on the under side. The object
of this conc is to diminish as much as possible the area of that part of
the valve subject to the influence of the issuing steam, and consequently
to increase the total pressure on the valve, causing it to lift higher than
it would otherwise do, and to continue to rise higher as the pressure in
the boiler incrcascs.
In order that my said Invention may be most fully understood and

page_text: •
on one side to serve as a frame for the fire-doorway, as is shown; c¹, c¹, are
the flanges by which the upper and lower parts of the shell of the boiler
are connected;. d is the cylindrical diaphragm to regulate the circulation
of the water in the boiler; it rests on studs provided to support it; e is
the flue or chimney springing from the top of the fire-box; the way in
which it is taken through the dome of the outer shell c by a packed
joint is an important feature of my Invention; fis the packing, by
preference of asbestos, contained in a cavity formed by the flange g,
which is fixed upon the dome; h is a ring for compressing the packing
to render the joint steam tight; i is a nut screwed down on to the
flange g, where it takes a good bearing, so that the fluce serves as a stay.
and sustains the pressure on the domes of the fire-box and of the shell;
k, k, are pressure screws which the nut i carrics, and when the nut i.has
been screwed home the pressure screws are brought down upon the
ring h, and the packing is compressed until a sound joint is made; is
the damper worked by a rod within the chimney, and by a lever, and
screw, as is shown; m is the steam chest, a peculiar feature of which is
that it is case contained within the interior of the boiler; it is perforated
at the top at m', m³, and any water that enters drains out again by the
pipe m². The steam pipe m³ has its mouth near the top of the steam
'chest.
.
The form of the safety valve is so fully shown that further description
of it is not required.
What I claim is the improvements in steam boilers, substantially as
described.
In witness whereof I, the said John Alison, have hereunto set my
hand and scal, this Thirteenth day of May, in the year of our
Lord One thousand cight hundred and seventy-five.