IMPROVEMENTS IN FURNACES
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by Robert Porter at the Office
of the Commissioners of Patents, with his Petition, on the 1st
July 1869.
I, ROBERT PORTER, of Birmingham, in the County of Warwick,
Mechanical Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN FURNACES," to be as follows:-
My Invention has reference principally to the furnaces of steam
boilers, but is also applicable to other furnaces, and it consists in the
formation and arrangement of the fire-bars and grates of such furnaces
in the manner herein-after described to secure the effectual combustion
of the fuel and the prevention of smoke. For this purpose I arrange
the fire-bars in the direction of the length of the furnace as with
ordinary fire-bars, and I make and fix the fire-bars, or a portion of
them, so that they rise by gradations one above another from both sides
towards the centre of the furnace, and form an elevation or ridge along
the middle of the fire-grate. I make the highest point of such elevation
or ridge to rise to about the level of or above the general upper
surface of the fuel, so as to divide the fuel and to deliver air in fine
streams through and between the bars to the fuel and to the volatile

page_text: gases arising from the fuel at the moment of their generation, when
with a due admixture of air they will readily ignite with good effect
instead of passing away unconsumed in the form of smoke as in ordinary
furnaces. The bars forming the ridge are maintained at suitable
distances apart as with ordinary furnace bars by means of fillets or
distance pieces formed preferably upon the said bars to correspond with
one another, and I prefer to groove the said bars and to serrate or notch
the edges of some of them in order to form numerous channels and
apertures for the passage of air between them in small streams or
jets; and I sometimes form tlie bars so as to deflect or otherwise
direct the air issuing from between or through them. As a means
of regulating the supply of air to correspond with the varying volume
of the gases produced in the furnace, I make the central or topmost
bar to form the apex of the ridge and to move freely between the bars
next adjoining it on either side, in order that it may be elevated or
depressed by means of levers fixed below or by any other convenient
means so as more or less to open or close the spaces or apertures
between it and the said adjoining bars. The bars composing the ridge
may be formed singly, or two or more, or the whole of them may be
formed or united together, and the apertures through and between
them may in some instances be so adjusted to the general requirements
of a furnace that no movement of the topmost bar may be necessary,
and the draught may be regulated by means of dampers in the chimneys
or flues, or by doors or valves fitted to the front of the ash-pit or
space beneath the fire-grate. For very wide grates more than one
air channel or ridge may be formed in the width of the grate.
My Invention may be applied to existing furnaces generally by
removing a few or the whole of the ordinary fire-bars and by substituting
the bars to form a ridge as herein-before described, or by such alter-
ations or additions to the existing bars or to the dead plates and bearers
which support them as shall cause them to form an elevation or ridge
as is herein-before described. Some of the grate bars may also be
made to rise one above another by gradations towards the sides of the
furnace, as a means of admitting air at the sides to the space above
the fuel if required.