IMPROVEMENTS IN HOT WATER BOILERS FOR HEATING BUILDINGS, GREENHOUSES, AND FOR OTHER HEATING PURPOSES
Year: 1876

page_text: LETTERS PATENT to John. Woodhouse Coulthard, of Croydon, in the County of
Surrey, Gentleman, for the Invention of "IMPROVEMENTS IN HOT WATER
BOILERS FOR HEATING BUILDINGS, GREENHOUSES, AND FOR OTHER HEATING
PURPOSES."
Sealed the 15th August 1876, and dated the 11th April 1876.
PROVISIONAL SPECIFICATION left by the said John Woodhouse Coulthard
at the Office of the Commissioners of Patents on the 11th April 1876.
JOHN WOODHOUSE COULTHARD, of Croydon, in the County of Surrey, Gentleman.
"IMPROVEMENTS IN HOT WATER BOILERS FOR HEATING BUILDINGS, GREEN-
HOUSES, AND FOR OTHER HEATING PURPOSES."
This Invention consists in improvements in boilers for heating water for various
purposes, whereby the water is heated at a less expense of fuel than hitherto.
According to this Invention; the waste heat, gases, and products of combustion
before leaving the boiler are caused to pass once, or more than once, through the
colder portion of the water, videlicet, that portion of the water which has just
entered the boiler by the return pipe; the heated water leaving the boiler at a.
point immediately over that at which the heat from the furnace concentrates, that
is to say, at the back end of the crown of the furnace.
One arrangement for carrying out my Invention, which I have found to answer
in practice, consists in constructing the boiler of an oblong or rectangular shape in
section, and with rounded corners, the furnace being placed at either side or in the
middle of the boiler. At one or both sides of the boiler, as the case may be, I
arrange two or more rows of flues (or tubes) in such a manner that the heat from
the back of the furnace passes through the upper row of flues to the front end of
the boiler, and thence through the next lower row of flues to the back end of the
boiler, then to the front again through the next lower row of flues, and so on; the
heat finally passing forward and backward under the bottom of the boiler, through
two suitably placed flues, and away by the chimney. If required the boiler may
be formed with a water back.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said John Woodhouse Coulthard in the Great Seal Patent Office on the
10th October 1876.
JOHN WOODHOUSE COULTHARD, of Croydon, in the County of Surrey, Gentleman.
"IMPROVEMENTS IN HOT WATER BOILERS FOR HEATING BUILDINGS, GREEN-
HOUSES, AND FOR OTHER HEATING PURPOSES."
This Invention consists in improvements in the construction of boilers for heating
water for various purposes, whereby the water is heated at a less expense of fuel
than hitherto.
•
By my improvements the waste heat, gases, and products of combustion before
leaving the boiler are caused without detriment to the draught of the furnace to
pass once, or more than once, through the colder portion of the water, videlicet, that
portion of the water which has just entered the boiler by the return or inlet pipes,
the heated water leaving the boiler at a point immediately over that at which the
heat from the furnace concentrates, that is to say, at the back end of the crown of
the furnace.
One arrangement for carrying out my Invention which I have found to answer
in practice consists in constructing the boiler of an oblong or rectangular shape in
section and with rounded corners, the furnace being placed at either side or in the
middle of the boiler. At one or both sides of the furnace, as the case may be, I
arrange two or more flue (or tubes) in such a manner that the heat from
the back of the furnace passes through the upper flues to the front end of the boiler,
and thence through the lower flues to the back end of the boiler, and out by a
suitably placed external flue or chimney, or the heat may be finally caused to again
pass forward and backward under the bottom of the boiler through two suitably
placed flues, and away by the said chimney. If required the boiler may be formed
with a water back.
But in order to make my Invention better understood I will now proceed to
describe the same by reference to the accompanying Drawing, in which Figure 1 is
a front elevation of a hot water boiler constructed according to my improvements;
Figure 2 is a horizontal section of same on line A, B, of Figure 1, and Figures
3 and 4 longitudinal sections on the lines C, D, and E, F, respectively. For
the convenience of illustration the brickwork setting of the boiler is omitted in
Figure 1. Similar letters of reference are used in all the Figures to represent
similar parts.
a, a, is the boiler, with the furnace b in the middle; at each side of the furnace I
form two flues one above the other, the upper flues being marked c, c¹, and the
lower flues d, d, each of the upper flues communicates with the furnace by an
opening e, and the front ends of both the upper and lower flues are open to the
flues ff, formed in the brickwork setting, while the back ends of the lower flues
d, d, open into the external flue at the back of the boiler terminated by a suitable
chimney; h, k, are openings (closed by suitable doors i, i,) to allow of cleaning out
the flues; is the furnace door; k, the dead plate; 7, the ash-pit; m, m, inlet pipes ;
n, outlet pipe; 0, 0, 0, water spaces of the boiler. The action of the boiler is as
follows: The heat and products of combustion pass from the furnace 6 through
the openings e, e, into the upper flues c, c', and then forward, as shewn by the
arrows, into the flues f, f, and descending pass into the lower flues d, d¹, and back-
ward into the external flue g, and away by the chimney. By this arrangement it
will be seen that the heat from the furnace has thus been caused to pass through
the colder portion of the water before passing away (and without detriment to the
draught of the furnace), thereby heating the water at a less expense than has
hitherto been effected with this class of boiler.
It will of course be understood that for small boilers the flues may be placed at
one side only of the furnace, whilst for larger boilers a larger number of flues may
be employed..
Having thus described my said Invention and the best means with which I am

page_text: acquainted for carrying the same into effect, I wish it to be understood that I do
not confine myself to the precise details herein laid down and shewn in the Drawing,
but what I do claim is the construction of hot water boilers for heating buildings,
greenhouses, and for other heating purposes, with flues at the side or sides of the
furnace, the whole arranged substantially in the manner and for the purposes
herein-before described and represented in the accompanying Drawing.
.
In witness whereof, I, the said John Woodhouse Coulthard, have hereto set
my hand and seal, this Tenth day of October, in the year of our Lord One
thousand eight hundred and seventy-six.
Witness,
G. F. REDFERN,
Patent Agent,
4, South Street,
Finsbury.
JOHN W. COULTHARD., (L.S.)
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