IMPROVEMENTS IN SPARK ARRESTERS
Year: 1871

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
•
in the County of Middlesex, Gentleman, for the Invention of
"IMPROVEMENTS IN SPARK ARRESTERS." A communication from
abroad by James Smith and Thomas William Worsdell, of Altoona,
County of Blair, State of Pennsylvania, United States of America.
Sealed the 20th October 1871, and dated the 22nd June 1871.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 22nd June 1871.
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 SPARK ARRESTERS," a communication to
me from abroad by James Smith and Thomas William Worsdell, of
Altoona, County of Blair, State of Pennsylvania, United States of
America; to be as follows:-
This Invention relates to a peculiar construction and arrangement of
spark arrester more particularly applicable to locomotive engine boilers,
but applicable also to the smoke boxes of the boilers of portable and

page_text: other engines wherein a steam blast is employed. Into the lower part
of the smoke box extends the exhaust nozzle, which communicates with
the contracted lower end of a tapering casing, the latter communicating
at the upper end with the lower end of the chimney. Perforations are
made in the casing sufficiently numerous to permit the smoke and gases
to pass freely from the smoke box without interfering with the draft,
these perforations forming the only means of communication between
the said box and the chimney; they are however of such size as to
effectually prevent the passage through them of all cinders not in a
finely divided, and unignited_condition. This casing may be made also
of wire gauze or of a piece of coiled bar iron forming a helical open
grating, or it may be composed of cast metal rings strung on to rods so
as to form a grating. Surrounding the case is a sleeve or outer casing
which extends to within a short distance of the top and bottom of the
smoke box, and which is made in two sections, the upper section being
secured to a cross bar and flaring outwards towards the top, and the
lower section flaring outwards towards the bottom and extending into
the lower end of the upper section so as to be vertically adjustable
within the latter to a limited extent by means of a set screw or other-
wise. At the upper end of the sleeve or outer casing are perforations
for a purpose described hereafter. The draft created in the chimney by
the exhaust steam causes the smoke and cinders to pass upwards between
the two casings, the smoke escaping freely through the perforations in
the inner casing and the ignited cinders being brought so violently in
contact with the same as to be more or less broken or triturated, the
finer particles passing through the perforations, whence they are dis-
charged through the chimney in a harmless condition, while the coarse
particles rise and fall between the two casings until by repeated violent
contact with the casings they are reduced to particles fine enough to
pass through the perforations. The perforations at the upper edge of
the outer casing form a counter or downward current to prevent the
lighter particles from passing upwardly through the top of the said
casing.
.
The inner grating may be made in any other desired manner than-
those set forth, provided it presents rigid bars or surfaces for the hard
ignited cinders to strike against, and provided there are openings suf-
ficient in number and size to permit the free escape of lighter particles
with the products of combustion.

page_text: 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 21st December 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Mid-
dlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of June, in the
year of our Lord One thousand eight hundred and seventy-one, in the
85th 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, administrators,
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,
exorcise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "Im-
PROVEMENTS IN SPARK ARRESTERS," a communication to me from abroad
by James Smith and Thomas William Worsdell, of Altoona, County
of Blair, State of Pennsylvania, 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 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 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 by the following statement, reference being had to the accom-
panying Drawings, and to the letters and figures marked thereon, that
is to say :-
The said Invention relates to a peculiar construction and arrange-
ment of spark arrester more particularly applicable to locomotive engine
boilers, but applicable also to the smoke boxes of the boilers of portable
and other engines wherein a steam blast is employed.

page_text: Figure 1 of the Drawings hereunto annexed is a longitudinal section of
a locomotive smoke box and part of the boiler with the improved spark
arrester; Figure 2 is a transverse section of the same on the line 1–2,
Figure 1; Figures 3 and 4 are transverse sections illustrating modifi-
cations of the Invention; and Figure 5 is a detached view illustrating
another modification.
-
In Figures 1 and 2 S is the outer shell of a locomotive boiler, at the
front end of which is the usual smoke box T, and above the latter
projects the chimney P. Into the lower part of the smoke box extends
the exhaust nozzle E which communicates with the contracted lower
end of a tapering casing A, the latter communicating at the upper end
with the lower end of the chimney P. The perforations in the casing A
are sufficiently numerous to permit the smoke and gases to pass freely
from the smoke box without interfering with the draft, these perfora-
tions forming the only means of communication between the said box
and the chimney; they are, however, of such size as to effectually
prevent the passage through them of all cinders not in a finely divided
and unignited condition. Surrounding the case A is a sleeve or casing B
which extends to within a short distance of the top and bottom of the
smoke box, and which is made in two sections a and a², the upper
section a being secured to a cross bar C and flaring outwards towards
the top, and the lower section a' flaring outwards towards the bottom
and extending into the lower end of the section a so as to be vertically
adjustable within the latter to a limited extent by means of a set screw t.
At the upper end of the casing B are perforations for a purpose :
described hereafter. The draught created in the chimney by the exhaust
stcam causes the smoke and cinders to pass upwards between the two
casings, the smoke escaping freely through the perforations in the inner
casing A, and the ignited cinders being brought so violently in contact
with the same as to be more or less broken or triturated, the finer 3
particles passing through the perforations, whence they are discharged
through the chimney in a harmless condition, while the coarse particles
rise and fall between the two casings until by repeated violent contact
with the casings A. they are reduced to particles fine enough to pass
through the perforations. The perforations at the upper edge of the
casing B form a counter or downward current to prevent the lighter
particles from passing upwardly through the top of the said casing..
The casing A of perforated sheet metal answers effectually for some
classes of fuel, but for other kinds, wood, for instance, it has been found

page_text: that a perforated casing is not as effectual as a casing A (Figure 3) of
wire guaze, which affords a free escape for the products of combustion,
and at the same time arrests the light cinders and affords an excellent
surface for the abrasion and disentegration of the same.
The hard coal a grated casing A' (Figure 4) is preferred; this may be
made of a continuous bar of wrought iron coiled spirally, as shewn, or it
may be composed of a number of cast-iron rings strung to thin rods, as
shewn in Figure 5, or the grating may be made in any other desired
manner, providing it presents rigid bars for the hard ignited cinders to
strike against, and providing there are openings sufficient in number and
size to permit the free escape of lighter particles with the products of
combustion.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may or 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 perforated pipe or casing A to which the cinders are directed ·
by the action of the exhaust steam and by 'a casing B or its equivalent,
all substantially as described.
Secondly. The grated or wire guaze casing A¹ or A' in combination
with the shield or casing B, the whole being arranged within a smoke
box, substantially as described.
Thirdly. The casing A or its equivalent, tapered at described, in com-
bination with the casing B having a flaring lower end.
Fourthly. The casing B consisting of a stationary section and an
adjustable section a', the whole being arranged substantially as specified.
Fifthly. The perforations in the casing B for the purpose specified.
In witness whereof I the said John Henry Johnson hown to
L