IMPROVEMENTS IN FURNACES FOR EFFECTING THE CONSUMPTION OF SMOKE
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the
Office of the Commissioners of Patents on the 11th December 1879. [A
cominunication from abroad by Stephen Marmont, of Sagene, Christiania,
in the Kingdom of Norway, and Charles Birch North, also of Christiania
aforesaid.]
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN FURNACES FOR EFFECTING THE CONSUMPTION
OF SMOKE." [A communication from abroad by Stephen Marmont, of Sagene,
Christiania, in the Kingdom of Norway, and Charles Birch North, also of Christiania
aforesaid.]
It has been found that upon coaling or adding fuel to a furnace fire that the first
volume of smoke, volatile fuel, or gases (but commonly known and described and
hereinafter referred to as smoke) emitted from such fire consists of an impure body
of coal, and is surrounded by an atmosphere of gas, so that on being brought into
contact with a highly heated or burning substance it will instantly ignite and be
consumed.
It has also been found that in a furnace there is not sufficient atmospheric air
admitted to cause the combustion of the smoke without other means are adopted
than are known, for if the fire door be opened the steam pressure would be lowered
by the admission of cold air, and even then the desired object would not be effected
on account of the density of the smoke and the great velocity with which it quits
the furnace, as in such a case the air would proceed in one current and the
smoke in another, thus leaving the smoke unmingled with the air and consequently
unconsumed.
Hitherto although there have been many Inventions having for their object to
effect the consumption of smoke it has not been accomplished, and the result is
a great annoyance from smoke and an immense waste of coal, it following as a
matter of course that were the smoke is unconsumed a like proportion of fuel is
lost.
According to this Invention in order to give every offect to the atmospheric air
admitted into an ordinary steam boiler furnace through the ventilator holes in the
fire door and also by the fire bars, tubes or tubular blocks constructed of fire clay
or other like substance are erected over the bridge of the furnace or other convenient
place at short distances apart, and in such a position as not to impair the draught
of the furnace, but throw the flame upwards on to the boiler plates, and thus create
more steam, the bottom of the spaces between the tubes being filled up with a thin

page_text: coating of fire clay or like material. The said tubes are kept at the proper
distances apart by filling pieces of firo clay at top, and by being received between
grooved ribs on the bridge at bottom. After the furnace fire has been lighted a
short time these tubes become white hot, and the smoke on coming in contact with
them instantly ignites, and a large proportion of it is consumed in consequence of its
particles being surrounded with the gaseous atmosphere and the atmospheric air
already in the furnace (as before referred to), while that smoke which is not so
brought into a state of combustion is retarded in its velocity, and as it has to pass
through the spaces between the tubes is divided into thin currents, thus more
especially fitting it for a current of hot atmospheric air which is brought to bear
upon it immediately, and before the currents of smoke have time to reunite from
underneath and at the back of the tubes. The air thus applied is heated, first, by
passing underneath the fire bars, and secondly, by traversing a sinuous or zigzag
passage or passages so constructed in the bridge itself as to bring the air into close
proximity with the furnace fire and so give the air a greater degree of heat.
It has been found, 1st, that the tubes at a white heat and in conjunction with
the air ordinarily admitted into furnaces effect the consumption of a large quantity
of smoke; 2nd, that the tubes without obstructing the draught retard the velocity
of the smoke, divide it into thin currents, and a large portion of it having been
previously consumed make it an easy matter for the hob air subsequently applied
to bring the remainder into a perfect state of combustion; 3rd, that the tubes will
last an indefinite period, are easily and inexpensively renewed, do not impair the
draught of the furnace, and have no ill effect upon and cause no alteration of the
boiler; 4th, that the hot air applied doce in no way lower the steain or injure the
boiler, which is the case with cold air or steam. A. door may be fixed to the
entrance of the hot air passage through the bridge, which can be opened or shut
to any degree desired by means of an iron rod passing under the fire-bars to a
holder fixed to the frame of the fire door for the greater convenience of the engineer
or fireman.
This apparatus is preferably so constructed that the former bridge of the furnace
can be removed and a new one substituted, ready fitted with the hot air passage,
and the tubes afterwards fixed as above described, and the ribs filled with fire clay.