IMPROVEMENTS IN MOVING FURNACH BARS
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by Henry Lawrence at the Office of
the Commissioners of Patents, with his Petition, on the 14th July
1868.
I, HENRY LAWRENCE, of the City of Durham, Engineer, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN MOVING
FURNACH BARS," to be as follows:-
This Invention relates to the construction, arrangement, and operation
of those furnaces wherein endless chains or rows of fire-bars travel
around drums or tumblers.
Hitherto the fire-bars forming an endless chain of bars have been
connected together by transverse through bolts and cotters, so that the
sides of the fire-bars are always in the same relative position one with
the other while travelling between the drums or tumblers.
Now part of my present improvements consists in dispensing with the
through bolts and cotters, and in so arranging the fire-bars that they
travel in one, two, or more endless chains or rows, and by alternately
varying the speed of each chain or row of fire-bars their sides are
prevented from being in continuous contact or maintaining the same
relative position one with the other during their movement from front

page_text: to back of the furnace. I also cause each fire-bar or alternate row of
fire-bars as they pass over the several supporting rollers to receive a
slight lifting and lowering motion, and the number or order of the fire-
bars receiving this motion may be varied to suit the description of coal
used. The varied speed of the fire-bars will in a great measure, if not
altogether, prevent the formation of clinker, and by the lifting motion
of the fire-bars the caking of the coal will be prevented.
Where
By this improved arrangement and action of the endless chains of
fire-bars more air will be allowed to pass through the fuel, so as to effect
its more perfect combustion. Where two or more chains or rows of fire-
bars are arranged to travel together according to my improvements I
connect the bars by casting projections on the sides of one bar to fit
into holes or recesses cast in the side of the adjoining bar, and in cases
where one chain or row of bars is used the same method of connecting
the bars may be employed by half lapping the ends of the bars.
steel or malleable iron fire-bars are used I roll the bars in the ordinary
manner, then saw them into lengths, and whilst hot I punch holes
through them; but in every alternate row of bars, instead of punching
the piece out of the side of the bar a projection is formed on the side of
the bar by a punch forcing it into a die about half the thickness of the
bar in depth, thus forming a projection to fit into the hole in the
adjoining bar.
In order to obtain a varied speed in the several rows of fire-bars
employed according to my improvements I alternately increase and
decrease the diameter of the driving drums as may be required. The
lifting and lowering motion given to the bars may be effected where
cast-iron bars are used by casting annular projecting pieces on the
bottom, or by making one bar rather deeper than the other in cases
where malleable iron bars are used.
The form of the fire-bars, together with the number of separate
endless chains of bars employed, and the manner of actuating them
may be considerably varied without departing from the nature of my
improvements.