IMPROVEMENTS IN THE CON- STRUCTION OF STEAM BOILERS AND FURNACES
Year: 1856

page_text: LETTERS PATENT to Frederick Peter Dimpfel, of the City and County of
Philadelphia, in the State of Pennsylvania, one of the United States of
of America, Engineer, for the Invention of "IMPROVEMENTS IN THE CON-
STRUCTION OF STEAM BOILERS AND FURNACES."
Sealed the 4th November 1856, and dated the 24th May 1856.
PROVISIONAL SPECIFICATION left by the said Frederick Peter Dimpfel
at the Office of the Commissioners of Patents, with his Petition, on
the 24th May 1856.
I, FREDERICK PETER DIMPFEL, of the City and County of Philadelphia, in
the State of Pennsylvania, one of the United States of America, Engineer,
do hereby declare the nature of the said Invention for IMPROVEMENTS IN THE
CONSTRUCTION OF STEAM BOILERS AND FURNACES, to be as follows:-
My Invention of improvements in the construction of steam boilers and
furnaces relates, firstly, to a method of constructing and arranging the lower
plates of the boiler, whereby the small particles of coal which are carried by
the force of the blast from the fire chamber into the flues may be consumed,
and made to assist in generating steam in the boiler, and which particles, if
not consumed, will clog the flues, and in some measure interfere with the
draught.
In order to cause these small particles of coal to be consumed, I admit air

page_text: thereto through small holes or openings made in the main flue of the boiler;
or a vessel or receptacle, with small apertures at or near the bottom thereof,
may be adapted to the main flue for the admission of atmospheric air, which
vessel or receptacle is fitted to a hole in the bottom of the main flue, behind the
fire chamber, and in front of a check or deflector introduced in the flue; or, if
preferred, the bottom of the flue may be recessed out, so as to form a chamber
to receive the small particles of coal that come from the fire, and by making
small holes therein, as before mentioned, air will be supplied to support com-
bustion. I find it necessary, however, to cover up these holes with metal plates,
so as to cause the air in entering to pass under the plates, and be divided into
a thin stratum, and highly heated, before it comes into contact with the fuel.
When the current induced by the draught or blast moves from the fire chamber
through the flue, and is deflected by the check or deflector, the fine particles of
coal which are carried by the current are so much checked in their motion that
they fall into the recess made in the bottom plate, or into the receptacle
employed in place thereof, and being in a highly heated state, the supply of
atmospheric air through the small apertures at or near the bottom of the said
receptacle, or of the bottom plate of the main flue, induces combustion, which
consumes the fine particles as fast as they are supplied. In this way the
clogging of the flues is prevented, and the heat in the flues increased.
The next part of my Invention relates to the disposition of the flue for
directing the products of combustion from among the water tubes in the main
flue to the smoke box, by a mode of construction which at the same time
facilitates the introduction and removal of the water tubes for the purpose of
repairs.
In the construction of tubular boilers, according to my former system, the
rear ends of the horizontal part of the water tubes are secured to a single
tube sheet, and the products of combustion, after circulating amongst the tubes,
are deflected, and carried by a flue at top or bottom around the edges of the
tube sheet to the smoke box behind.
This mode of construction has been found to be objectionable, for the reason
that the deflection of the products of combustion prevents the heat from acting
on the rear ends of the middle tubes, and the tube sheet, being a single plate,
required the tubes, when taken out for repairs, to be removed through the front
or furnace door, which for that reason had to be located with special reference
to the removal of the tubes.
To obviate the defects above mentioned, I propose to make the back tube
sheet in two parts, with a space cut out in the middle, to form a flue space
leading from the middle of the group of tubes to the smoke box behind. By

page_text: this means the products of combustion will have a more direct action on the
rear ends of the tubes, and the middle flue space leading to the smoke box will
facilitate the removal of the water tubes when required.
Instead of securing the bent-up ends of the water tubes to a perfectly flat
horizontal crown plate, as heretofore, I propose to employ a concave plate, the
concavity being upwards, and by attaching or securing the water tubes to a
crown plate of this description, 1 find that a smaller number of strengthening
bars are required than if a flat plate is used. I also propose to arrange the
bent-up ends of the water tubes in the crown plate of the furnace in a some-
what different manner to that heretofore adopted.
My improved arrangement consists in connecting the bent-up end of the
water tubes with the crown sheet of the boiler in a series of double rows in
the direction of the length of the boiler, placing the tubes constituting cach
double row very near to each other, and the double rows at a greater distance
apart than the external diameter of the several tubes. In this way any tube
when disconnected can be moved laterally to one of the wide spaces, so that it
may be drawn out. The required amount of space is given for the volume of
flame and heated gases, whilst at the same time a greater number of tubes
can be put in a boiler of a given size than if the spaces between the several
tubes were greater than the external diameter of the tubes. The flame and
gases passing up freely in the wide spaces will spread laterally, and thus act
with nearly as good an effect as if wide spaces were left between all the rows
of tubes.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frederick Peter Dimpfel in the Great Seal Patent Office
on the 24th November 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
PETER DIMPFEL, of the City and County of Philadelphia, in the State of
Pennsylvania, one of the United States of America, Engineer, send greeting.
WHEREAS Iler most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of May, in the year of our Lord
One thousand eight hundred and fifty-six, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Frederick Peter Dimpfel, Her special liceuce that I, the said Frederick Peter
Dimpfel, my executors, administrators, and assigus, or such others as I, the said

page_text: Frederick Peter Dimpfel, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times there-
after 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 THE
CONSTRUCTION OF STEAM BOILERS AND FURNACES," upon the condition' (amongst
others) that I, the said Frederick Peter Dimpfel, 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 Frederick Peter Dimpfel, do hereby
declare the nature of my 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 Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
This Invention relates, firstly, to the employment of certain means for
effecting the consumption of the small particles of coal which are carried by
the force of the blast from the fire chamber into the flues, and thereby apply-
ing such particles to the generating of steam in the boiler, and preventing the
clogging of the flues with dust, which frequently occurs, especially in locomotive
engines, greatly to the interference of the draught.
In the accompanying Drawing, Fig. 1 shews, in longitudinal section, the
boiler and furnace of a locomotive engine constructed according to my Inven-
tion; Fig. 2 is a sectional plan of the same, taken at about the line 1, 2, of
Fig. 1 i and Fig. 3 is a cross section, taken at the zig-zag line 3, 4, of
Fig. 2.
In order to effect the consumption of the fine particles of fuel carried for-
ward by the draught of the furnace, I bring in contact therewith jets of air,
which enter through small holes or openings a, made in the bottom plates b of
the main flue of the boiler; or I fit to the bottom of the main flue a receptacle
or receptacles c, in advance of the fire chamber, and opening into the main
fiue, for the purpose of receiving the floating particles of fine coal; and such
receptacles provide with air holes a, for admitting jets of air and facilitating
the combustion of the particles of coal, which are arrested in their forward
progress by deflectors d, d, introduced for that purpose into the flue.
I
By reference to the Drawing, it will be seen that the tubes of the boiler are
arranged in two groups, a considerable space being left between them for the
play of the flame. Within this space the deflectors d, d, are s.t, so as to stop

page_text: the direct passage of the gases of combustion, and consequently retard or stop
the progress of the fine particles of fuel held in suspension. The holes a are
covered with deflecting plates c, so as to cause the air on entering to pass under
the plates, and spread into a thin stratum, and become highly heated, before it
comes into contact with the fuel. When the current induced by the draught
or blast moves from the fire chamber through the flue, and is deflected by
the check or deflector d, the floating particles of coal which are in a state of
ignition will fall, anl, coming under the action of the thin stratum of air,
will be rapidly consumed.
I may remark, that the diameter of the air holes a, and also the distance
between them and the deflecting plate e, which arrest the ascending current of
air and spread it into a thin film, will vary considerably, according to the nature
of the fuel used in the furnace; but as a guide, I may state that the air holes
will in general be about half an inch in diameter, covered with a plate, measur-
ing, say, three and a half inches in diameter, which plate should be set above
the hole from about one-sixteenth to three-sixteenths of an inch. By the use
of this system of jets, the clogging of the flues will be prevented, and the heat
in the flues increased.
The next part of my Invention relates to the disposition of the fluo for
directing the products of combustion from among the water tubes in the
main flue to the smoke box, by a mode of construction which at the same
time facilitates the introduction and removal of the water tubes for the purpose
of repairs.
In the construction of tubular boilers, according to a system which I
formerly proposed, the rear ends of the water tubes are secured to a single
tube sheet or plate, and the products of combustion, after circulating around
and amongst the tubes, are deflected and carried, by a flue at top or bottom,
around the edges of the tube sheet to the smoke box behind.
This mode of construction has been found to be objectionable, for the reason
that the deflection of the products of combustion prevents the heat from acting
on the rear ends of the middle tubes, and the tube sheet, being a single plate,
required the tubes, when taken out for repairs, to be removed through the front
or furnace door, which for that reason had to be located with special reference
to the removal of the tubes.
To obviate the defects above mentioned, I propose to make the back tube
slicet in two parts, as shewn at f. f. Figures 2 and 3, with a space g between
them, to form a flue space leading from the middle of the groups of tubes to
the smoke box h behind. By this means the products of combustion will have
a more direct action on the rear ends of the tubes, the middle flue space leading

page_text: to the smoke box will also permit of the easy removal of the water tubes when
required.
Instead of securing the bent-up ends of the water tubes to a perfectly flat
horizontal crown plate, as heretofore, I propose to employ a concave plate i (the
concavity being upwards, as shown), and by attaching or securing the water
tubes to a crown plate of this description, I find that a smaller number of
strengthening bars is required than when a flat plate is used; I also proposo
to arrange the bent-up ends of the water tubes in the crown plate of the
furnace in a somewhat different manner to that heretofore adopted.
My improved arrangement consists in connecting the bent-up ends of these
tubes with the crown sheet i of the boiler in a series of double rows, ranging
in the direction of the length of the boiler, the several tubes constituting each
double row being placed as near to each other as is judged convenient for the
efficient heating of the same, but the double rows at a distance apart, about
equal to or even superior to the external diameter of the several tubes. In
this way any tube when disconnected can be moved laterally to one of tho
wide spaces, so that it may be drawn out. A suflicient amount of space is
thus given for the play of the volume of flame and heated gases amongst the
tubes, whilst at the same time a greater number of tubes can be put in a boiler
of a given size than if the spaces between the several tubes were greater than
the external diameter of the tubes. The flame and gases passing up freely in
the wide spaces will spread laterally, and thus act with about as good an effect
as if wide spaces were left between all the rows of tubes.
Having now set forth the nature and object of my Invention of "Improve-
ments in the Construction of Steam Boilers and Furnaces," and explained the
manner of carrying the same into effect, I wish it to be understood that under
the above in part recited Letters Patent I claim,―
First, arranging the tubes of tubular boilers so as to form a flue between
them, as explained, and placing in this central flue a deflector or deflectors
for checking the momentum of the particles of fuel carried forward from
the fire chamber by the draft, and causing them to fall to the bottom of
the flue.
Secondly, connecting with the bottom of the main flue, containing the tubes,
receptacles suitable for receiving the fine particles of the fuel arrested in their
progress through the central fluc.
Thirdly, fitting in the bottom of the main flue or flues of steam boilers, an
in the bottom of the receptacles, air tubes, covered by deflecting plates, for the
purpose of introducing air to the fine particles of fuel, and causing it to impinge
thereon in a thin film to assist in consuming the fuel.

page_text: And, lastly, I claim connecting the bent-up ends of the water tubes to a
concave crown sheet, in a series of double longitudinal rows, with spaces
between the double rows, of a width proportioned to the diameter of the
tubes, to admit of the easy removal of old and insertion of new tubes,
whilst in other respects the said tubes are placed as near to each other as
may be desired.
In witness whereof, I, the said Frederick Peter Dinpfel, have hereunto
set my hand and seal, the Ninth day of September, in the year of
our Lord One thousand eight hundred and fifty-six.
F. P. DIMPFEL. (L.S.)