IMPROVEMENTS IN STEAM BOILERS
Year: 1876

page_text: LETTERS PATENT to Thomas Fletcher Passman, of Middlesbrough-on-Tees, in
the County of York, Boiler Maker, for the Invention of "IMPROVEMENTS IN
STEAM BOILERS."
Sealed the 20th February 1877, and dated the 24th August 1876.
PROVISIONAL SPECIFICATION left by the said Thomas Fletcher Passman at
the Office of the Commissioners of Patents on the 24th August 1876.
THOMAS FLETCHER PASSMAN, of Middlesbrough-on-Tees, in the County of York,
Boiler Maker. "IMPROVEMENTS IN STEAM BOILERS"
This Invention relates to improvements in steam boilers, especially those used for
marine purposes, whereby greater strength and efficiency together with the more
perfect combustion of the fuel will be attained than is at present the case.
In constructing steam boilers according to this Invention three furnaces are
employed, the flues of which all end in the same combustion chamber, so that by
keeping one of the fires always bright the carbonaceous gases from the other
furnaces are ignited whilst passing through the combustion chamber to the return
flue Above the three furnaces is placed an elliptical return tube or flue provided
with a suitable number of "Galloway" tubes, as will be well understood, and
through which elliptical return tube the heated gases pass from the combustion
chamber. As all the gases are ignited in the combustion chamber an equal heat is
maintained throughout the Hues, and by this means all unequal contraction and
expansion is obviated, and the smoke otherwise resulting entirely consumed.
The rear end of the boiler together with the end of the combustion chamber is
made circular and to the same radius as the boiler shell, thus doing away with all
flat surfaces, longitudinal stays, and short screw stays, and enabling the boilers to be
worked at a much higher pressure than at present.
It will be understood that from the peculiar form of the boiler and the absence of
all longitudinal and other stays easy access can be had to all parts thereof for the
purpose of examining, cleaning, or repairing the same.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Thomas Fletcher Passman in the Great Seal Patent Office on the 22nd
February 1877.
THOMAS FLETCHER PASSMAN, of Middlesbrough-on-Tees, in the County of York,
Boiler Maker. "IMPROVEMENTS IN STEAM BOILERS."
My said Invention relates to certain improvements in steam boilers, especially
those used for marine purposes, whereby greater strength and efficiency, together
with more perfect combustion of the fucl will be attained than is at present the
case.
In constructing steam boilers according to this Invention three furnaces are
employed the flues of which respectively end in the same combustion chamber, so
that by keeping one of the fires always bright the carbonaceous gases from the
other furnaces are ignited whilst passing through the combustion chamber to the
return flue. Above the three furnaces is placed an elliptical return tube or flue
provided with a suitable number of "Galloway" tubes, as will be well understood,
and through which elliptical return tube or fluo the heated gases pass from the
combustion chamber. As all the gases are ignited in the combustion chamber an
equal heat is maintained throughout the flues, and by this means all unequal con-
traction and expansion is obviated, and the smoke otherwise resulting entirely
consumed.
The rear end of the boiler together with the end of the combustion chamber is
made circular, and to about the same radius as the boiler shell, thus doing away
with all flat surfaces, longitudinal stays, and short screw stays, and enabling the
boilers to be worked at a much higher pressure than at present.
It will be understood that from the peculiar form of the boiler and the absence
of all longitudinal and other stays easy access can be had to all parts thereof for the
purpose of examining, cleaning, or repairing the same.
I will now proceed to refer to the annexed Drawings, from which the nature of
my said Invention will be more clearly understood.
Figure 1 shews the boiler in front and sectional elevation, Figure 2 is a longi-
tudinal section, and Figure 3, a sectional plan The latter Figure shews half of
the return tube and combustion chamber, and also half section of the combustion
chamber and right side furnace.
Having thus declared and ascertained the nature of my said Invention, and in
what manner the same is to be performed, I would observe in conclusion that what
I consider novel and original, and therefore clann as being the Invention secured
to me by the said herein-before in part recited Letters Patent are, the improve-
ments in the construction of steam boilers, substantially as herein-before described
and set forth.
In witness whereof, I, the said Thomas Fletcher Passman, have hereunto set
my hand and seal, this Twentieth day of February, in the year of our
Lord One thousand eight hundred and seventiz_cowan