IMPROVEMENTS IN STEAM BOILERS
Year: 1874

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn
Fields, in the County of Middlesex, Gentleman, for the Invention
T
of "IMPROVEMENTS IN STEAM BOILERS."-A communication from
abroad by George Granville Lobdell, of Wilmington, County of
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 7th July 1874.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN STEAM BOILERS," a communication to
me from abroad by George Granville Lobdell, of Wilmington, County
of New Castle, State of Delaware, United States of America, to be as
follows:-
The object of this Invention is the construction of a steam boiler
which shall bear a high pressure; absorb or utilize as much as possible

page_text: a plate, which extends upwards into the body of the boiler to a point
below the waterline, and downwards to a point below the surface of the
grate bars. This plate necessarily induces a circulation down and up
the leg, and this circulation prevents all deposit of sediment on the top
of the lower tube sheet, for all sediment is carried down the leg with the
water, and is left in the leg below the lower edge of the plate, and can
be withdrawn from time to time by blow-off pipes. This is an important
feature of the Invention, as one of the most serious objections to vertical
tubular boilers is the accumulation of sediment on the top of the lower
tube plate, and the consequent rapid destruction of the said plate, and
of the lower ends of the tube.
Another defect of vertical tubular boilers is their tendency to prime,"
a tendency attributable to the crowding of parallel tubes together in the
steam space. This difficulty is obviated, according to this Invention, by
so arranging the tubes that while they are in the usual close proximity.
to each other at the lower tube sheet, they will diverge from this point
upwards, so that where they pass through the steam space of the boiler
they are at such a distance apart from each other that the surface of
the water remains in a comparatively quiescent state, which cannot
be maintained in the presence of a crowded group of heated tubes.
It will be understood that the exposed exterior of the boiler should,
be clothed with non-conducting material, as in ordinary marine boilers.
Another feature which assists in preventing priming is an annular
steam chamber provided with three or more branches secured to the top
of the boiler, these branches having comparatively small openings.
This annular chamber has a branch to be attached to the steam pipe,
and a branch for receiving the safety valve, or combined safety and
shut-off valve.
When the boiler is required for use in connection with stationary
engines the body of the boiler is enclosed within a square casing of
brick work, so that the products of combustion after passing from the
tubes into the smoke chamber will dive into a space which is provided.
between the brickwork and shell of the boiler, and then pass upward
through pipes which project downward into the said space and com-
municate with another space above and thence with the chimney, the
shell of the boiler being thus subjected to the action of the products of
combustion prior to the escape of the same.

page_text: It is preferred to convey the steam from the top of the boiler through
a pipe to a drum
or steam chest with which the steam pipe
communicates.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 1st January 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventh day of July, in the year
of our Lord One thousand cight hundred and seventy-four, in the
38th year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Henry Johnson, Her special
license that I, the said John Henry Johnson, my executors, admini-
strators, and assigns, or such others as I, the said John Henry
Johnson, my executors, administrators, or 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 STEAM BOILERS," a communication to me from abroad
by George Granville Lobdell, of Wilmington, County of New Castle,
State of Delaware, United States of America, upon the condition
(amongst others) that I, the said John Henry Johnson, my executors
or administrators, by an instrument in writing under
my hand
and seal, should particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be per-
formed, and cause the same to be filed in the Great Scal 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 Henry Johnson, 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

page_text: by the following statement, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to
say:-
The said Invention has for its object the construction of a steam
boiler which shall bear a high pressure; absorb or utilize as much as
possible all the heat produced by the burning of the fuel; insure a more
effective consumption of smoke and a consequent reduction in the
quantity of fuel required; maintain the interior of the boiler, more
particularly the lower tube sheet, free from sediment; superheat the
steam to a degree necessary for economy; and prevent the priming of
vertical boilers having small tubes.
And in order that the said Invention may be fully understood, I shall
now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the annexed Sheet of Drawings,
the same letters of reference indicating corresponding parts in all the
Figures.
Figure 1 represents a vertical section of the boiler as arranged for use
on a steamboat, and Figure 2 is a sectional plan taken along the
line 1, 2, Figure 1; Figure 3 is a vertical section of the boiler as
arranged for stationary engines, and Figure 4 is a sectional plan taken
along the line 3, 4, Figure 3.
The outer casing or shell A of the boiler is in Figures 1 and 2 made
of the tapering form represented, so as to accommodate the peculiarly
arranged tubes B, the latter diverging from the lower tube plate a¹ to
the upper tube plate a, which arrangement is, according to the said
Invention, in some cases adopted for the purpose herein-after explained.
D. is the smoke chamber contained within. the tapering casing E,
which connects the upper tube plate a with the chimney G, the shell of
the boiler also extending to the chimney, and assuming a form corre-
sponding with that of the internal casing E. The water is maintained
at about the level indicated by the line a, a, so that the upper portion
of the tubes and the casing of the smoke chamber D are surrounded by
steam, which is consequently maintained by intimate contact with these
hot surfaces in the desired superheated condition.
The lower portion of the boiler below the bottom tube sheet is cut
away in front to the extent of about half its diameter, thus leaving a

page_text: semi-cylindrical leg H (see Figure 2), within which a circulation of
water is maintained in the manner herein-after explained.
In front of the lower portion of the boiler thus cut away are built
the opposite side walls d and d', and front wall e of the fire-place I, as
shewn clearly in the sectional plan, Figure 2, the fire-place being
furnished with the usual grate bars, fire-door, and ash-pit.
It has been found by practical tests that a more effectual consumption
of smoke is obtained in a fire-place bounded by brick walls than in one
surrounded by the iron of the boiler, this being attributable to the fact
that the walls of the fire-place, when the boiler is in full operation,
are always maintained at a red heat, and consequently act as smoke
consumers.
.
As the leg H forms the back of the fire-place it is essential that a
continuous circulation of water should be maintained therein down to a
point below the grate bars. This circulation is secured by means of the
plate J, which extends upwards into the body of the boiler to a point
below the waterline, and downwards to a point below the surface of the
grate bars. This plate necessarily induces a circulation down and up
the leg in the direction of the arrows, which circulation prevents all
deposit of sediment on the top of the lower tube sheet, as all sediment
is carried down the leg with the water, and is left in the leg below the
lower edge of the plate J, whence it may be withdrawn from time to
time by blow-off pipes m. This is an important feature of the Invention,
as one of the most serious objections to vertical tubular boilers is the
accumulation of sediment on the top of the lower tube plate, and the
consequent rapid destruction of the said plate, and of the lower ends of
the tube.
Another defect in vertical tubular boilers is their tendency to prime,
a tendency attributable to the crowding of parallel tubes together in the
steam space. This difficulty is obviated, according to the said Invention,
by so arranging the tubes that while they are in the usual close
proximity to each other at the lower tube sheet, they will diverge from
this point upwards, so that where they pass through the steam space of
the boiler they are at such a distance apart from each other that the.
surface of the water remains in a comparatively quiescent state, which
cannot be maintained in the presence of a crowded group of heated
tubes.

page_text: It will be understood that the exposed. exterior of the boiler should
be clothed with non-conducting material, as in ordinary marine boilers.
Another feature which assists in preventing priming is the annular
steam chamber M, which is provided with three or more branches p
secured to the top of the boiler, such branches having comparately
small openings. This annular chamber is also provided with a branch q
to be attached to the steam pipe, and a branch t for the reception of the
safety valve, or combined safety and shut-off valve.
Figures 3 and 4 shew the improved boiler. as arranged for use in
connection with stationary engines, the body of the boiler being inclosed
within a square casing A' of brickwork, so that the products of com-
bustion after passing from the tubes into the smoke chamber D will dive
into the space n between the brickwork and the shell of the boiler, and
then pass upward through pipes w, wo, which project downward into the
said space n and communicate with the space y and thence with the
chimney G, the shell of the boiler being thus subjected to the action of
the products of combustion prior to the escape of the same.
It is preferable to convey the steam from the top of the boiler
through a pipe f to a drum or steam chest T, with which the steam
pipe f communicates.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that what I consider
to be novel and original, and therefore claim as the Invention secured
to me by the herein-before in part recited Letters Patent is,--
First. A vertical tubular boiler having below the lower tube sheet
a continuation or leg forming the rear or part of the rear of a fire-place,
substantially as herein-before described and illustrated by the accom-
panying Drawings.
Second. The combination of the said leg with a fire-place, the sides
and front of which are composed of brickwork, all substantially as and
for the purposes herein-before described and as illustrated by the
accompanying Drawings.
Third. The combination of the plate J with the body and leg H of a
vertical tubular boiler, substantially as herein-before described and
illustrated by the accompanying Drawings.

page_text: Fourth. A vertical tubular boiler, in which the tubes diverge from the
lower tube plate to the upper tube plate, substantially as herein-before
described and illustrated by the accompanying Drawings.
Fifth. The annular steam chamber M connected to the boiler, sub-
stantially as herein-before described and illustrated by the accompanying 5
Drawings.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, the First day of
January One thousand eight hundred and seventy-five.