IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES FOR STEAM BOILERS AND OTHER PURPOSES
Year: 1860

page_text: PROVISIONAL SPECIFICATION left by Joseph Sawyer at the Office of
the Commissioners of Patents, with his Petition, on the 9th March
1860.
I, JOSEPH SAWYER, of London, in the County of Middlesex, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
CONSTRUCTION OF FURNACES FOR STEAM BOILERS AND OTHER PURPOSES," to be as
follows:-
This Invention relates, firstly to an improved construction of fire-bars;
secondly, to an improved construction of fire-bridge; and, thirdly, to an
improved construction of fire-doors.
The improved fire-bars are formed with vertical grooves in the sides for
the admission of air to the furnace, the grooves being so formed that in
casting the fire-bars no cores are required, and the pattern can be easily
withdrawn from the mould. The grooves on one side of the bar are opposite
to the spaces on the other side thereof, so that in one position of the bars they
are suitable for burning coke, and by reversing the same they are then suitable
for burning coal. These bars are lighter, less costly, more durable, and more
efficacious than those at present in use.
The improved fire-bridge is constructed as follows:-The upper part of the
bridge is carried up to within from three to six inches from the upper side of
the flue, and is straight or curved to conform to the shape of the same. The
upper part of the bridge is curved forwards, so as to deflect the smoke and
gases, and direct them towards the centre, and at the centre of the bridge is

page_text: an opening sloping upwards. The action of this arrangement is, that the
smoke and gases are prevented from escaping immediately over the top of
the bridge, and are thrown or directed towards the central aperture, where
they become ignited, and are directed upwards against the upper surface of
the flue or the bottom of the boiler or other vessel, and the smoke and gases
are thereby entirely consumed, and a much greater amount of heat or
evaporating power can be obtained with a smaller expenditure of fuel than
with bridges of the ordinary construction.
My improved fire-door is designed principally to be used in small furnaces
wherein it is desirable to supply the fuel (when required) without opening the
furnace door, such as the furnaces used by gold refiners, and in other cases
where an intenso and continued heat is required. The door is made of a
double or box form, and at the upper part is a hopper or receptacle for the
fuel, provided with a slide at the bottom, and a "shoot" or slope inside the
door. At the bottom part of the latter is a small opening (closed with a
slide) through which a shovel is introduced, the handle thereof being outside,
and the rod passing through a hole in the door. The hopper being filled with
fuel, when the fire needs a supply the slido is withdrawn, and the fuel falls
into the shovel inside the furnace, when the slide is immediately closed. The
stoker then advances the shovel, tilting it at intervals so as to distribute the
fuel evenly over the fire, and then draws the shovel back to the door ready
to give a fresh supply of fuel when needed.