IMPROVEMENTS IN STEAM BOILERS
Year: 1872

page_text: LETTERS PATENT to William Gray, of Highwood House, Hendon,
in the County of Middlesex, for the Invention of “IMPROVEMENTS IN
STEAM BOILERS."
Sealed the 6th August 1872, and dated the 11th March 1872.
PROVISIONAL SPECIFICATION left by the said William Gray at the
Office of the Commissioners of Patents, with his Petition, on the
11th March 1872.
I, WILLIAM GRAY, of Highwood House, Hendon, in the County of
Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN STEAM BOILERS," to be as follows:-
This Invention has for its object improvements in steam boilers. In
the construction of boilers for locomotives and other uses I employ a
cylindrical shell with tubes passing through it from end to end; there
is a fire-box at one end and a smoke box at the other; the chimney is
over the fire-box, and the products of combustion return to it over the
top of the cylindrical shell by a flue, the top and sides of which form a
water tank from which the feed for the boiler is drawn, and I take the

page_text: water from the surface condenser into this tank. A second cylinder of
smaller diameter is fixed immediately over the top of the larger cylin-
drical shell already mentioned; the larger and the smaller boiler cylinders
are connected throughout their length by a number of short vertical
tubes, and these together with the smaller cylinder are enclosed within
the return flue, by which the products of combustion return from the
smoke box to the chimney. The top of the fire-box is below the top of
the larger cylinder of the boiler; tubes pass through the steam space,
and a portion of the draft from the smoke box to the chimney passes
back by them. I screw the tubes into the tube plates. I make one end
of the tube where the thread is cut upon it rather larger than the other,
and the body of the tube I make of such a size that the tube may pass
freely into its place through the tube plate. Sometimes I do not tap
the holes in the tube plate with screw threads, but simply fit the tubes
into them, each tube having a head at one end and receiving a nut at
the other. The tubes which connect the two cylinders of the boiler are
screwed into their places from within the larger cylinder. The holes in
both cylinders are tapped to receive the tubes, and the tubes receive
nuts within the smaller cylinder, whilst their other ends terminate in
heads of octagonal or other form.
For use in steamboats and for other purposes I construct double
boilers resembling two single boilers joined at the fire-box end by a
connecting water space, which forms a combustion chamber. The upper
or smaller cylinder is common in this case to the two larger cylinders,
and extends over both of them.
Furnaces are constructed in brickwork beneath the larger cylinders,
and the flames from them meet in the combustion chamber. To promote
the circulation of the water in the larger cylinders I fix within them, on
either side, plates which divide the upward from the downward flow. I
feed the boiler both with water and air by means of a rotary pump. In
place of a number of tubes, the larger cylinder of the boiler may have
one large flue through it and within it; to increase the heating surface
and strengthen the flue a number of short upright tubes may be fixed.
In these boilers there is combined into one structure very efficient means
of evaporating the water, drying and superheating the steam, and
heating the feed water.

page_text: сопитнопо
me Letters fatent,
filed by the said William Gray in the Great Seal Patent Office on
the 10th September 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
GRAY, of Highwood House, Hendon, in the County of Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of March, in the year
of our Lord One thousand eight hundred and seventy-two, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said William Gray, Her special
license that I, the said William Gray, my executors, administrators,
and assigns, or such others as I, the said William Gray, 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 STEAM BOILERS," upon the condition (amongst others) that I, the
said William Gray, 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 William Gray, 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. In
the construction of boilers for locomotives and marine and other uses I
employ a cylindrical shell or barrel with tubes passing through it from
end to end; there is a fire-box or combustion chamber at one end and.
a smoke box at the other; the chimney is over the fire-box, and the

page_text: products of combustion return to it over the top of the cylindrical shell
or barrel by a flue, the top and sides of which form a water tank from
which the feed for the boiler is drawn, and into which I exhaust steam
whenever I can, and when a surface condenser is used I take the water
from the surface condenser into this tank. A second cylinder or barrel
of smaller diameter is fixed immediately over the top of the larger
cylindrical shell or barrel already mentioned; the larger and the smaller
boiler cylinders or barrels are connected throughout their length by a
number of short vertical tubes, and these together with the smaller
cylinder or barrel are enclosed within the return flue by which the
products of combustion return from the smoke box to the chimney. The
top of the fire-box is below the top of the larger cylinder or barrel of the
boiler; tubes pass through the steam space above the fire-box, and a
portion of the draft from the smoke box to the chimney passes back by
them. I screw the tubes into the tube plates, I make one end of the
tube where the thread is cut upon it rather larger than the other, and
the body of the tube I make of such a size that the tube may pass freely
into its place through the tube plate. Sometimes I do not tap the holes
in the tube plate with screw threads, but simply fit the tubes into them,
each tube having a head at one end and receiving a nut at the other.
The tubes which connect the two cylinders or barrels of the boiler
are screwed into their places from within the larger cylinder or barrel.
The holes in both cylinders or barrels are tapped to receive the tubes,
and the tubes receive nuts within the smaller cylinder or barrel, whilst
their other ends terminate in heads of octagonal or other form.
For use in steamboats and for other purposes I construct double
boilers resembling two single boilers, joined at the fire-box end by a
The upper
connecting water space which forms a combustion chamber.
or smaller cylinder or barrel is common in this case to the two larger
cylinders or barrels, and extends over both of them.
Furnaces are constructed in brickwork beneath the larger cylinders
or barrels, and the flames from them meet in the combustion chamber.
To promote the circulation of the water in the larger cylinders or
barrels I fix within them on either side plates which divide the upward
from the downward flow. I sometimes feed the boiler both with water
and air by means of a rotary pump. In place of a number of tubes
the larger cylinder or barrel of the boiler may have one large flue
through it, and within this flue to increase the heating surface and

page_text: strengthen the flue a number of short upright tubes may be fixed. In
these boilers there is combined into one structure very efficient means
of evaporating the water, drying and superheating the steam, and
heating the feed water.
In order that my said Invention may be most fully understood, and
readily carried into effect, I will proceed to describe the Drawings here-
unto annexed.
Figure 1 is a vertical section of a locomotive boiler constructed
according to my Invention. a is the cylindrical shell or barrel of the
boiler; is the fire-box surrounded by a water space; c is the smoke
box; d, d, are tubes passing from the fire-box to the smoke box, and
there are other tubes d', d', which pass through the barrel a over the top
of the fire-box; they lead back a portion of the products of combustion
through the steam space in the upper part of the barrel a, and so dry
the steam; e is a return flue passing back over the top of the barrel a
to the chimney f; g is a saddle tank to contain the feed water; it forms
the top and sides of the flue e; h is a cylinder mounted above the
barrel a within the flue; e and i are tubes connecting the cylinder h
with the barrel a, so that the cylinder h forms a steam receiver from
which the steam is taken by the steam pipe i* to the working cylinder
of the engine; k is the starting lever by which the valve ¹ on the steam
pipe is opened and closed; is the exhaust pipe leading as is usual to a
blast pipe in the chimney; the blast pipe passes in its way to the
chimney through the saddle tank g, and heats the water therein. I also
make arrangements to exhaust direct into the water in the tank. At m
is the injector; it draws the water from the saddle tank 9, circulates
it in the feed pipe n within the flue e, and then forces it into the
boiler.
Figure 2 is a back view partly in section of the locomotive boiler; the
section is taken through the cylinder. Figure 3 is a front view also
partly in section; the section is taken through the fire-box.
Figure 4 is a section of one of the tubes d; it is screwed through the
two tube plates, and receives a nut beyond the further one. At the
other end there is a head upon the tube, and at this end the screw is
slightly larger than at the other, so that the tube may be passed

page_text: freely forwards; or the holes in the tube plates may be plain, as is
shewn in Figure 5.
Figure 6 is a section of one of the tubes i; the construction is similar
to that described in respect to Figure 4, except that lock nuts are
added.
Figure 7 shews another method of fixing these tubes, there being in
this case no thread in the hole in the barrel a of the boiler. By these
arrangements every tube in the boiler becomes a stay, and all of them
can be easily removed.
Figures 8 are similar to Figures 4, 5, 6, and 7, but are drawn to a
. larger scale.
a, a,
Figure 9 is a longitudinal section of a double boiler constructed
according to my Invention; this form is suitable for marine use.
are the cylindrical shells or barrels of the boiler, and the furnaces are
constructed beneath them within iron casings which support the boiler
as is shewn. For stationary boilers this casing may be omitted, and a
brickwork setting substituted. b is a chamber enclosed by water spaces
between the two shells or barrels a; this chamber, which corresponds
with the fire-box of the single boiler, now forms a combustion chamber;
c, c, are the smoke boxes; d, d, are the tubes passing from the com-
bustion chamber to the smoke boxes; and d', d', are other tubes passing
through the upper parts of the boiler shells or barrels a above the com-
bustion chamber; e is a return flue passing back over the tops of the
barrels a to the central chimney f; g is a saddle tank containing the
feed water, and enclosing the flue e; h is a cylindrical steam space
common to the two parts of the double boiler, and the steam pipe which
is perforated passes through it; i, i, are tubes connecting the cylinder h
and the shells or barrels a; is the exhaust pipe which traverses the
saddle tank g on its way to the surface condenser; n is the feed pipe by
which water is drawn from the tank g by an injector or pump, and
forced into the boiler; this pipe, in order further to heat the feed water,
circulates around the flue e; o is a pipe by which the water is drawn
from the surface condenser, and returned to the tank g; p, p, are pas-
sages by which heated air is conveyed to meet the gases rising from the
fuel just as they enter the combustion chamber; q, q, are passages for
the removal of soot or particles of fuel which may be carried into the
combustion chamber..

page_text: Figure 10 is a transverse section taken on the line 1, 1, in Figure 9.
Figure 11 is an end view one-half in section on the line 2, 2; and
Figure 12 is an horizontal section taken on line 3, 3, in the same Figure;
,, in Figure 10 are plates to direct the circulation of the water.
Figure 13 is a transverse section of a ship shewing two such double
boilers fixed side by side within it.
Having thus described the nature of my said Invention, and the
manner of performing the same, I would have it understood that I claim
the construction of boilers with a return flue over the top of the barrel,
and enclosed by a feed water tank, substantially as described.
I also claim the construction of boilers, substantially as described and
shewn in the annexed Drawings.
I also claim the means of fixing boiler tubes, described and shewn in
the annexed Drawings.
In witness whereof, I, the said William Gray, have hereunto
set my hand and seal, this Twenty-sixth day of August, in
the vear of our Lord One thousand eight hundred and seventy