IMPROVEMENTS IN HOT WATER BOILERS
Year: 1883

page_text: LETTERS PATENT to James Keith of the City and County of Edinburgh, Gas
and Water Engineer for an Invention of "IMPROVEMENTS IN HOT WATER
BOILERS
"2
PROVISIONAL SPECIFICATION left by the said James Keith at the Office
of the Commissioners of Patents on the 22nd September 1883.
JAMES KEITH, of the City and County of Edinburgh, Gas and water Engineer,
"IMPROVEMENTS IN HOT WATER BOILERS,"
This Invention relates to improvements in the construction of boilers for heating
water and causing it to circulate through hot water coils, and similar heating
apparatus.
According to one modification, the improved boiler consists of a water casing
which is of annular form in horizontal section, or is formed with an outer and
inner shell by preference of circular, oval or oblong shape in plan. The casing is
cast in a single piece in which respect mainly it differs from the sectional form of
boiler described in the Specification of Letters Patent granted to me, and dated
22nd April 1882, No 1920. An inlet opening is formed near the bottom of the
water casing at the back, and an outlet near the top, or more than one inlet or
outlet may be provided, but these are the only openings in the boiler. To these
openings the inlet and outlet pipes of the usual water heating and circulating coils
or apparatus are connected. The water casing surrounds or forms the containing
walls of a fire which rests on a dumping fire grate fitted in a hollow base on which
the water casing rests. A small doorway is provided in front to give access to the
fire. The fuel is fed in from the top by an opening which is fitted with a cover
or a covered funnel, and the products of combustion escape by a second opening
behind fitted with a chimney flue. Between these openings over the fire a water
circulating tube forming part of the casing, connects the sides of the annular water
casing and receives the heat of the fire. At the back of the fire, a fire brick

page_text: slab is fitted and held in a recess formed in the inner shell of the water casing to
protect it from the direct action of the fire.
When the boiler is circular in plan, the circulating tube is made in the form of a
deep channel round the covered opening which is fitted in the centre for the
admission of the fuel, and one or more cross tubes connect the sides to provide for
circulation of the water, and prevent burning of the metal. The circulating tube
or channel may reach down nearly to the top of the fire, a space being left round
it between the fire and the top of the boiler. The inner shell of the boiler is by
preference corrugated to increase the surface exposed to the action of the fire.
The water casing being made of a single casting and the base and fire covers
and other parts being cast of simple form, the whole can be made cheaply, and can
be put together without any fitting or preparing of joints or similar surfaces.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Keith in the Patent Office on the 20th March 1884.
JAMES KEITH, of the city and county of Edinburgh, Gas and Water Engineer
"IMPROVEMENTS IN HOT WATER BOILERS,"
My said Invention relates to improvements in the construction of boilers for
heating water and causing it to circulate through hot water coils, and similar
heating apparatus.
My Invention is illustrated in the accompanying Drawings, in which Figure 1
is a vertical section and Figure 2 a horizontal section of a modification of the
improved hot water boiler.
According to this modification, the improved boiler consists of a water casing a,
which of annular form in horizontal section, or is formed with an outer and
Inner shell A and A³, by preference of circular, oval, or oblong shape in plan.
16
The casing is cast in a single piece, in which respect mainly it differs from the
sectional form of boiler described in the Specification of Letters Patent granted to
me, and dated 22nd April, 1882, No 1920. An inlet opening B is formed near the
bottom of the water casing a at the back, and an outlet B₁ near the top, or more
than one inlet or outlet may be provided, but these are the only openings in the
boiler. To these openings B, B³, the inlet and outlet pipes of the usual water
beating and circulating coils or apparatus are connected. The water casing a
surrounds or forms the containing walls and top of a fire which rests in a
dumping" fire-grate C fitted in a hollow base A' on which the water casing
rests. A small doorway D is provided in front to give access to the fire, and it is
fitted with a movable door D¹ protected by a fire-clay lining. The fuel is fed in
from the top by an opening E, which is fitted with a cover E¹, or a tapered hopper
or funnel E which is movable and interchangeable with the cover_E³, and which
has also a cover on the top fixed, as shown, by a bayonet joint, The products of
combustion escape by a second opening F behind, fitted with a loose damper piece
slipped over a rim cast on the boiler top, and this opening F can be connected to
a chimney flue or to a metal smoke pipe. Between these openings E, F, over the
fire, a water circulating tube a¹ forming part of the casting, connects the sides and
top of the annular water casing a and receives the heat of the fire. At the back
of the fire, a fire brick slab G is fitted and held in a recess G¹, formed in the
inner shell A¹ of the water casing to protect it from the direct action of the fire,
and to keep in the fire when it is damped down or is low, When the boiler is
circular in plan the circulating tube a¹ is made in the form of a deep channel round
the covered opening E, which is fitted in the centre for the admission of the fuel,
and forms a top casing of water between the smoke exit and the fuel inlet, and
other parts of the top exposed to the fire; and one or more cross tubes may
connect the sides to provide for circulation of the water and to prevent burning
of the metal. The circulating tube or channel a' may reach down nearly to the
top of the fire, a space being left round it between the fire and the top of the
boiler to serve as a combustion chamber. The inner shell A¹ of the boiler is by
preference corrugated to increase the surface exposed to the action of the fire.
The water casing being made of a single casting, and the base A' and fire covers
and other parts being cast of simple form, the whole can be made cheaply, and can
be put together without any fitting or preparing of joints or similar surfaces.

page_text: Having now particularly described the nature of my said Invention, and in
what manner the same is to be performed, I declare that what I claim is,―
First. The combination of parts forming the improved hot water boiler herein
described and illustrated.
Second. A hot water boiler or water casing formed of a single casting with
inlet and outlet openings, substantially as herein described and illustrated.
In Witness Whereof, I, the said James Keith have hereunto set my hand and
seal this seventeenth day of March, in the year of our Lord One thousand eight
hundred and eighty four.
THYATT