IMPROVEMENTS IN STEAM BOILERS OR GENERATORS
Year: 1869

page_text: LETTERS PATENT to Bartholomew Charlton Crawford, of Newcastle-
upon-Tyne, Engineer, for the Invention of "IMPROVEMENTS IN STEAM
BOILERS OR GENERATORS "
PROVISIONAL SPECIFICATION left by the said Bartholomew Charlton
Crawford at the Office of the Commissioners of Patents, with his Petition,
on the 1st March 1869.
I, BARTHOLOMEW
CHARLTON CRAWFORD, of
Newcastle-upon-Tyne,
Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN STEAM BOILERS OR GENERATORS," to be as follows:-
This Invention relates to a peculiar arrangement of the furnaces and
combustion chambers of tubular or other boilers or generators of steam or other
gases, and has for its object the attainment of greater strength to withstand
high pressures, dispensing with the necessity for many stays, securing an
intense combustion in the furnaces and chambers' before the gases or products
of combustion enter the tubes or flues, and the reduction of the body of water
to be carried in the boiler.

page_text: At
It is proposed to construct a plain cylindrical vessel, forming the
body of the boiler, having two ends which form the tube plates, and
in which are inserted in the usual manner the ends of the tubes or
flues. This cylindrical vessel is intended to be placed horizontally or
slightly inclined, and to be nearly filled with tubes or small flues, a
sufficient number of which are arranged to act as stays to the flat
tube plates, having the requisite water spaces between them. At the
upper part a certain space is left clear above the water line to allow
of the ready escape of the steam from the surface of the water as it
is generated. On the top of the boiler and connected to it is a
large cylindrical steam chamber or receiver for collecting the steam and
partially superheating or drying it. The furnace or furnaces are formed
underneath the boiler, having their sides constructed of iron boxes
with water spaces formed in them, and lined with fire-brick or other
non-conducting substance next the fire. The bottom of the boiler thus
forms the top of the furnaces, and the fire-bars and grates are carried
on bearers fixed to the sides and provided with ash-pits below.
the back end of the boiler is the combustion chamber, forming an iron
casing filled with water to a certain height, and communicating with
the water spaces of the furnace sides. This chamber is lined throughout
with fire-brick and surrounds the whole of the back tube plate, the
ends of the tubes opening into it to receive the flame and gases
generated in the furnaces which after passing through the tubes enter
a smoke box or chamber at the front end, and are then conducted
by a flue or flues surrounding the steam receiver or chamber to the
chimney. The water contained in the side spaces of the furnaces
and in the casing of the combustion chamber is not liable to be under
pressure, being simply intended to absorb and utilize the surplus heat
given out by the fire-brick linings, and is supplied from suitable
reservoirs or tanks by gravitation or otherwise, kept at a uniform
level, being pumped into the boiler as feed water as it is heated
in the water spaces, and should any steam be generated from this water
(though this is not anticipated) it will be taken away by an escape
pipe at the top of the combustion chamber casing. In order to protect
that part of the boiler forming the top of the furnaces from injury
by the fire, owing to the deposit of sediment in the concave part
of the interior, it is proposed to provide one or more pipes or pockets
into which all sediment will subside and be blown out by proper cocks,
and these pipes or pockets may, if necessary, be protected from the

page_text: action of the fire by fire-brick cases. Or the bottom of the boiler
over the furnaces may be entirely removed from the intense heat in the
furnaces by being lined with arched fire-brick, so that the flame and
gases generated in the furnaces will be concentrated in the combustion
When it is
chamber at the point of entering the tubes or flues.
required to use two or more boilers they can be set side by side or back
to back, in which latter case it is proposed to arrange them in such
a way that one combustion chamber is common to two boilers; on the
in
duplex plan the construction of the other parts is the same as
the single boiler. The principal advantages to be derived from the boiler
here described are simplicity of construction, the capability of using
with safety steam or gases at very high pressures, no part of the boiler
or receiver being subjected to collapsing pressure except the tubes,
which being of comparatively small diameter are well able to sustain
it, the non-liability to "priming," the circulation being easy and a large
steam space being provided, lightness of the boiler in proportion to the
working pressure, and the great reduction of the weight of water to
be carried. In addition it is thought that the cost of the boiler
in proportion to the working pressure will be less than that of any other
high-pressure boiler of equal power. Although the cylindrical form
is preferred to any other the body of the boiler and the receiver may
be made oval, rectangular, or of any
of any other shape by the use of
stays, but for high pressures the cylindrical boiler is proposed to
be adopted. It is believed that the fire-brick linings of the furnaces and com-
bustion chamber will have the action of reverberating and intensifying the heat
of the gases in the same way as in a reverberatory furnace and that they will
act as reservoirs of heat to be restored according to the requiréments of the
evaporation.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
the said Bartholomew Charlton Crawford in the Great Seal Patent
Office on the 1st September 1869.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of March, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Bartholomew Charlton Crawford, Her
special license, that I, the said Bartholomew Chariton Crawford, my
executors, administrators, and assigns, or such others as I, the said
Bartholomew Charlton Crawford, 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 "IMPROVEMENTS IN STEAM BOILERS
GENERATORS," upon the condition (amongst others) that 1, the said
Bartholomew Charlton Crawford, 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.
OR
NOW KNOW YE, that I, the said Bartholomew Charlton Crawford,
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 accompanying Drawings, and to the letters and figures marked thereon,
that is to say;-
My said Invention relates to a peculiar arrangement of the furnaces and
combustion chambers of tubular or other boilers or generators of steam or other
gases, and has for its object the attainment of greater strength to withstand
high pressures, dispensing with the necessity for many stays, securing
an intense combustion in the furnaces and chambers before the gases or pro-
ducts of combustion enter the tubes or flues, and the reduction of the body of
water to be carried in the boiler.
And in order that my 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.

page_text: Figure 1 of the Drawings represents in transverse vertical section
taken through the furnace and in end elevation a pair of boilers
constructed according to this Invention; Figure 2 is a longitudinal
vertical section of one of the boilers; Figure 3 is a transverse vertical section
taken through the combustion chamber; Figure 4 shows a pair of similar boilers
placed back to back in lieu of side by side as in Figure 1, and Figure 5 is a
transverse section shewing a modification in the construction of the furnace
and the furnace lining.
A is a plain cylindrical vessel forming the body of the boiler, having
two ends B, B, which form the tube plates, and in which are inserted
in the usual manner the ends of the tubes or flues. This cylindrical
vessel is intended to be placed horizontally or slightly inclined, and
to be nearly filled with tubes or small flues, a sufficient number of
which a, a, are arranged to act as stays to the flat tube plates
having the requisite water spaces. between them. At the upper
part Ca certain space is left clear above the water line to allow
of the ready escape of the steam from the surface of the water as it is generated.
On the top of the boiler and connected to it is a large cylindrical steam
chamber or receiver D for collecting the steam and partially super-
heating or drying it. The furnace or furnaces E is or are formed
underneath the boiler, having their sides constructed of iron boxes F
with water spaces formed in them. The furnaces are lined with
fire-brick G or other non-conducting substance next the fire.
of the boiler thus forms the top of the furnaces and the
grates are carried on bearers H fixed to the
ash-pits I below. At the back end of the
chamber J, forming an iron casing K filled with water to a certain
height and communicating with the water spaces F of the furnace sides.
This chamber is lined throughout with fire-brick and surrounds the
whole of the back tube plate, the ends of the tubes opening into it
to receive the flame and gases generated in the furnaces, which after
passing through the tubes enter a smoke box or chamber L, at the
front end and are then conducted by a flue or flues surrounding the
steam receiver ог chamber D to the chimney. The water contained
in the side spaces E of the furnaces, and in the casing K of the com-
bustion chamber, is not liable to be under pressure, being simply intended
to absorb and utilise the surplus heat given out by the fire-brick linings,
The bottom
fire-bars and
sides and provided with
boiler is the combustion

page_text: heated in the water spaces.
and is supplied from suitable reservoirs or tanks (by gravitation or
otherwise) and kept at an uniform level, being pumped into the boiler
as feed water as it is
Should any
steam be generated from this water (though this is not anticipated) it will be
taken away by an escape pipe M at the top of the combustion chamber
casing.
In order to protect that part of the boiler forming the top
of the furnaces from injury by the fire, owing to the deposit of sediment
in the concave part of the interior, it is proposed to provide one
or more pipes or pockets N on to which all sediment will subside and
be blown out by proper cocks, and these pipes or pockets may, if necessary,
be protected from the action of the fire by fire-brick cases; or the
bottom of the boiler over the furnaces may be entirely removed from
the intense heat in the furnaces by being lined with arched fire-brick
(Figure 5), so that the flame and gases generated in the furnaces will
be concentrated in the combustion chamber J at the point of entering
the tubes or flues. When it is required to use two or more boilers
they can be set either side by side (see Figure 1) or back to back (see
Figure 4), in which latter case it is proposed to arrange them in such
a way that one combustion chamber J is
common to two boilers;
in the duplex plan the construction of the other parts is the same as in the
single boiler. The principal advantages to be derived from the boiler
here described are simplicity of construction, the capability of using
with safety steam or gases at a very high pressure, no part of the boiler
or receiver being subject to collapsing pressure except the tubes, which
being of comparatively small diameter are well able to sustain it, the
non-liability to "priming," the circulation being easy and a large
steam space being provided, lightness of the boiler in proportion to
the working pressure, and the great reduction of the weight of water
to be carried. The cost of the boiler in proportion of the working
pressure will be less than that of any other high-pressure boiler of
equal power. Although the cylindrical form is preferred to any other
the body of the boiler and the receiver may be made oval, rectangular,
or of any other shape by the use of stays, but for high pressures the
cylindrical boiler is preferred. The fire-brick linings of the furnaces
and combustion chamber will tend to reverberate and intensify the
heat of the gases in the same way as in a reverberatory furnace, and they will
act as reservoirs of heat to be restored according to the requirements of the
evaporation.

page_text: Having now described and particularly ascertained the nature of my 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. The peculiar construction and arrangement of steam boilers or
generators, whereby collapsing strains are practically avoided, substantially as
herein-before described and illustrated by my Drawings.
Second. The peculiar arrangement of the furnaces and combustion chambers
of steam generators, whereby they are not subjected to pressure as herein-
before described and illustrated by my Drawings.
In witness whereof, I, the said Bartholomew Charlton Crawford, have to
this my Specification set my hand and seal, this 31st day of August One
thousand eight hundred and sixty-nine.
B. C. CRAWFORD. (L.S.)