IMPROVEMENTS IN BURNING LIME AND CEMENT, AND IN APPARATUS EMPLOYED THEREIN
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by Robert Elsdon at the Office
of the Commissioners of Patents, with his Petition, on the. 24th
June 1868.
I, ROBERT ELSDON, of Brockham, in the County of Surrey, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN BURNING LIME AND CEMENT, AND IN APPARATUS EMPLOYED THEREIN," to be as
follows:-
This Invention has for its object improvements in burning lime and
cement, and in apparatus employed therein.
In calcining lime and cement I employ a rotating furnace. I construct
the furnace of a tubular form; it is closed at one end and at the other it
is tapered or contracted to a mouth of a much smaller area than the
transverse section of the tube. This furnace is mounted in a frame in
such manner that it may be rotated about its longitudinal axis. There
is a stud or axis fixed at the centre of the closed end of the furnace,
which stud is held in a bearing on the frame. At the other end of the

page_text: frame there is a ring which embraces the contracted part of the furnace
immediately behind the mouth. The frame also has small rollers upon
it supporting the furnace at points intermediate of its length, so as not
to interfere with its rotation. The frame which thus carries the furnace
is itself mounted on trunnions, so that by tipping on these trunnions it
may direct the axis of the furnace upwards or downwards or horizontally
as may be required. The interior of the furnace casing is lined with
fire-brick throughout, and it is divided into two compartments by a
transverse partition. The compartment adjacent to the closed end is
the fire-box, and small coal is let down at each rotation into it, an
opening in the periphery of the fire-box coming beneath a hopper from
which the coal descends; this opening is closed by a suitable cover, ex-
cepting at the times when it is beneath the hopper. The air to supply the
fire in the fire-box enters by perforations in the end of the furnace, and
the air is compelled. to pass through the fuel by a fixed cover plate on
the exterior, which closes the perforation in the furnace end as soon as in
the course of rotation they rise above the fuel. The flame passes from the
fire-box into the body of the furce by openings in the transverse partition.
In the body of the furnace are ve or other number of radial ribs of fire-
brick springing from the circumferential lining and extending about half-
way to the centre; these ribs are arranged in the direction of the length of
the furnace, and are either parallel with the axis or inclined to it. When
the furnace is in a horizontal position its mouth is applied to an opening
into a chimney, and thus a draft is caused through it, and this draft may
be regulated by a damper. In the chimney a receptacle is formed to
receive the charge of chalk, limestone, or cement, and it is preferred
that it should be in small pieces in a powdered state. In the receptacle
the charge receives a preparatory drying; then it is let down into the
body of the furnace through the mouth, which is raised for the charge
to descend into it from the drying receptacle. The axis of the furnace
is then brought to a horizontal position and the rotation is commenced
and continued until the lime or cement is properly burnt. Afterwards
the mouth of the furnace is depressed and the charge is shot out, leaving
the furnace ready to receive at once another charge from the drying
receptacle. The tipping of the furnace may be effected by a curved
rack fixed to the frame gearing with a pinion or worm on an axis carried
in stationary bearings. The fire-box need not necessarily revolve; it
may be stationary, and the flame from it may nevertheless be caused to

page_text: pass into the revolving body, as already described. A heater may be
placed in the chimney to supply a heated blast to the furnace, or it may
be to heat feed water for a steam boiler or otherwise to utilize the waste
heat.