IMPROVEMENTS IN REVIVIFYING SPENT LIME, AND IN THE MEANS OF APPARATUS THEREFOR
Year: 1878

page_text: LETTERS PATENT to George Robertson Hislop, of Paisley, Gas Engineer, and-
William Young, of Clippens, Oil Works Manager, both in the County of
Renfrew, North Britain, for the Invention of "IMPROVEMENTS IN REVIVIFYING
SPENT LIME, AND IN THE MEANS OF APPARATUS THEREFOR."
Sealed the 16th August 1878, and dated the 20th April 1878.
PROVISIONAL SPECIFICATION left by the said George Robertson Hislop and
William Young at the Office of the Commissioners of Patents on the 20th
April 1878.
GEORGE ROBERTSON HISLOP, of Paisley, Gas Engineer, and WILLIAM YOUNG, of
Clippens, Oil Works Manager, both in the County of Renfrew, North Britain.
"IMPROVEMENTS IN REVIVIFYING SPENT LIME, AND IN THE MEANS OR APPARATUS
THEREFOR."
This Invention relates to improvements in revivifying or again rendering caustic
lime which has been made foul in the process or operation of purifying coal or other
illuminating gas. Lime which has been otherwise rendered foul, for example, in
cases such as the manufacture of soap, soda ash, caustic soda, or other operations or
processes, may also be revivified or again rendered caustic by the new or improved
means or apparatus employed under this Invention.
The means or apparatus consists of a cylinder or cylinders formed of any suitable
material, preferably iron protected by a fire-clay covering. The interiors of such
cylinders are in communication with a furnace wherein carbonaceous matter is
burned, or with a steam boiler for the purpose of facilitating the removal of gaseous
impurities by passing steam through the lime, and the cylinders are slowly rotated
or oscillated by a tangent screw and worm wheel, or by the equivalent thereof, and
they may be placed over each other in such manner that the lime may be charged
into the upper cylinder, passing thence from cylinder to cylinder in one direction,
whilst the products of combustion pass therethrough in an opposite direction.
In place of using a series of cylinders, as herein-before mentioned, one longer and
inclined cylinder may be substituted.

page_text: Under another construction of the revolving cylinder it may be divided into two,
three, four, or more compartments arranged inside an outer cylindrical or equivalent
case; the purport of this construction being that the spent lime shall expose as
large a surface as possible to the action of the products of combustion from the
furnace.
All the forms of the rotating or oscillating revivifying apparatus herein-before
described are provided with hoppers or receivers, or the equivalents thereof, for
charging the foul lime into them, and they are also provided with one or more
chambers for receiving the lime after it has passed through the rotating or oscil-
lating cylinders. These last-mentioned chambers are for the purpose of either
allowing the lime to cool down before being exposed to the atmosphere, and the
air employed for this cooling becomes thereby heated preparatory to combustion
with the fuel of the furnace.
The supply of lime to the revivifying apparatus herein-before described may be
either intermittent or continuous, in the latter case the apparatus is preferably fitted
with feeding rollers, screw feeders, or their equivalent.
The interior of the revolving or oscillating cylinders herein-before described may
be fitted with continuous or discontinuous ribs, either spirally or longitudinally, for
the purpose
of aiding the turning over of the lime and regulating its delivery
through the retorts whilst being burnt. These ribs also have the effect of exposing
a larger surface of the lime to the action of the revivifying gases.
It is also preferred that the framework in which the rotating or oscillating retorts
are carried should be fitted with screws, levers, or the equivalent thereof for
adjusting the position of the retorts from time to time, as may be required.
At the upper end the rotating or oscillating cylinders may be connected to an
exhauster when it is desired to collect the gaseous or condensible substances
passing off or produced by the action of the fire gases or steam upon the foul lime.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Robertson Hislop and William Young in the Great Seal
Patent Office on the 16th October 1878.
GEORGE ROBERTSON HISLOP, of Paisley, Gas Engineer, and WILLIAM YOUNG, of
Clippens, Oil Works Manager, both. in the County of Renfrew, North Britain.
"IMPROVEMENTS IN REVIVIFYING SPENT LIME, AND IN THE MEANS OR APPARATUS
EMPLOYED THEREFOR."
Our said Invention relates to improvements in revivifying or again rendering
caustic lime which has been made foul in the process or operation of purifying coal
or other illuminating gas, or in the manufacture of soap, soda ash, caustic soda, or
in other operations or processes.
:
And in order that our said Invention may be properly understood we now proceed
more particularly to set forth the system, mode, or manner in or under which the
same is or may be used or practically carried into effect, reference being had to the
accompanying Drawings, and to the letters and figures marked thereon, that is to
say,-
In Figure 1 of the accompanying Drawings is represented one arrangement of the
It consists of a
means or apparatus we employ for carrying out our Invention.
series of chambers A', A2, A3, which are situated one immediately above the other;
and formed of any suitable material, but preferably of iron protected by an internal
lining of fire-clay. The chambers are supported at either end upon antifriction
rollers carried in the grooved brackets e, the circular ribs f fixed to the said
chambers running on the said rollers. The ends of the said chambers enter
sockets formed by circular angle irons g. The chambers A1, A2, A3, are slowly
rotated by a tangent screw b, gearing with a tangent wheel c fixed to one of the
chambers, the motion being communicated to the other chambers by toothed
gearing d. The said chambers A', A2, A3, are open at either end, and these open
ends are in communication with inclined flues C, C, and up-take flues C¹, C¹, the
said flues and chambers forming a continuous passage from the furnace B (wherein
carbonaceous matter is burned), to the chimney at D. The chambers A', A2, A³,
are provided with openings closed by doors a, through which the lime may be
charged into the said chambers. The said doors are shewn in the Drawings as
being doors which open by sliding in grooves in the direction of the length of the
chambers, but they may be lined with fire-clay and secured by a slip bolt to the
chamber, or fastened in any other convenient manner. The process of revivifying
spent lime is carried on by submitting the lime in each rotating chamber for the
necessary length of time to the action of the products of combustion from the
furnace B, which products pass upwards over the lime in the chambers in a direction
(as indicated by the arrows) the reverse of that in which the lime passes down-
wards through the series of chambers. After the lime has been thus treated the
apparatus is brought to rest, the door a of the chamber A³ opened, and the lime in
a revivified condition is discharged from the lower chamber A³, allowed to cool.
After the lower chamber is thus emptied the lime in the next chamber A³ above is
discharged therefrom into the chamber A³, and the lime from the upper chamber A¹
is discharged into the middle chamber A2, foul lime being fed into the upper
chamber A¹, the several doors a being opened to admit of the necessary discharge
from and reception of the lime into the several chambers. The doors a are then
closed, and the apparatus again set in motion as before, this being continued until
the lime in the lowest chamber A³ is revivified, when it, as well as the other
chambers A', A2, are again discharged and refilled in the manner herein-before
described.
Although we have described an apparatus with three rotating chambers it will be
evident that other number than three may be similarly employed.
+

page_text: By this apparatus for carrying on the process of revivifying spent lime the lime
in the upper chamber or chambers is desulphurized by the carbonic acid discharged
from the lime in the lower chamber or chambers, and the lime in the lower chamber
or chambers being submitted to the more intense heat from the furnace has thereby
the carbonic acid expelled therefrom. The flues C, C, are continued through to the
outside of the brickwork, where they are closed by doors h. This arrangement
allows of the insertion of a rake or tool by which to thrust the lime from the
cylinders in discharging. A flue may be provided leading direct to the chimney
from the furnace, which flue may be closed when the apparatus is in operation, but
direct communication therethrough is established when the chambers are being
emptied, the flue from the furnace being then closed; and all this may be effected
by any of the well-known arrangements of dampers.
In place of using a series of chambers, as herein-before described, one longer and
inclined cylinder or chamber may be substituted, as shewn in Figure 2, where such
a cylinder or chamber is marked A. Its interior is in communication at its lower
end with a furnace B, and at its upper end with a flue D, leading to a chimney.
The lime to be revivified is passed into the upper end of the cylinder or chamber A
from a hopper E, being directed into the said cylinder or chamber by an inclined
guide i, and the fuel is fed to the furnace from a hopper F. The cylinder or
chamber A is slowly rotated by means of a tangent screw b, gearing with a tangent
wheel c, upon the said cylinder or chamber. The products of combustion in this
case also pass in one direction, as indicated by the arrows, over the lime which is
caused to travel in the reverse direction by the rotation of the cylinder or chamber A,
the said lime falling gradually from the lower end of the said cylinder or chamber
into a chamber G, in which it cools, its cooling being facilitated, if desired, by
admitting air to the said chamber through openings, as shewn at j, this air becoming
heated and passing into the apparatus, assisting the process and economising the
fuel burnt in the furnace B. The action of the products of combustion in revivifying
the lime is the same in this case as in that of the apparatus illustrated in Figure 1.
Figure 3 illustrates in vertical section another arrangement of apparatus according
to our Invention. In this arrangement the cylinders or chambers A¹, A2, A³, are
inclined alternately in the reverse direction, so that the process of revivification
may be carried on continuously. The lower cylinder A³ is slowly rotated by the
worm band worm wheel c, and this motion is communicated to the other cylinders by
the toothed gearing wheels d, d. The cylinders are supported and turn upon grooved
guides e, e, furnished with antifriction rollers, and set in the brickwork, as shewn,
and the interiors of the said cylinders communicate with each other by means of
the flues C2, Cs. The lime to be revivified is fed into the top of the upper cylinder A',
and slowly descending falls upon the inclined bottom of the flue C, into which its
lower end opens, and thence into the upper end of the cylinder A². Descending
this cylinder in like manner the said lime falls upon the inclined bottom of the
flue C3 into which its lower end opens, and then passing through the bottom
cylinder As falls therefrom into the cooling chamber G, as described with regard to
Figure 2, in a revivified condition owing to the action of the products of combustion
passing in the reverse direction from the furnace B, after the manner herein-before
explained with reference to Figure 1, and as indicated by the arrows. As explained
with regard to Figure 2 air may be admitted to the said chamber G by passages as
at j.
Figure 4 is a vertical section, and Figure 5 is a section at right angles thereto,
taken on the line 1, 2, Figure 4, of a modification of this last preceding arrange-
ment, in which the chambers are of a conical form, they being arranged so that
they present inclined bottoms for the lime to descend, as described with regard to
Figure 3. The chambers are rotated by a worm b, worm wheel c, and toothed
gearing d, as described with regard to the other Figures. The lime and the products
of combustion pass continuously through these chambers, as described with regard
to Figure 3. The said chambers are supported, as shewn in Figure 5, upon anti-

page_text: friction rollers l, l, carried by brackets m, m, bolted to the brickwork. Parts of the
arrangement illustrated in this Figure, which correspond with the parts of the
arrangement, Figure 3, are marked with the same letters of reference.
Figure 6 represents a modification of the arrangement illustrated in Figure 2, as
in that arrangement there is one main inclined cylinder or chamber A, but in this
arrangement the interior of said cylinder is divided into a number of smaller
cylinders or chambers a', a², a³, a, as seen in Figure 7, which is a transverse section
of the said main cylinder.
The small internal cylindrical chambers are shewn as being made by longitu-
dinal passages through a fire-clay core in the main cylinder but they may be made
in any other convenient way. Although four such smaller chambers are shewn in
Figure 7, there may be more or less than four as may be found convenient. The
small chambers a', a², a³, a' are open at their lower ends to receive the products of
combustion from the furnace B, at their upper ends they communicate with a flue D
leading to a chimney. A hopper E is arrauged at the upper part of the cylinders
and the passage e¹ therefrom is in such a position that the open upper ends of
the small chambers a¹, a², a³, at, all pass before the said passage during the rotation
of the main cylinder, which rotation is effected as in the arrangement Figure 2.
The lime to be revivified is fed to the small chambers a³, a², a³, a, as they come
opposite the passage e', the main cylinder being stopped for a short period to admit
of each chamber receiving its charge of lime, which, passing down the said small
chambers, falls into the cooling chamber G in a revivified condition, being in its
passage thoroughly submitted (by the rotation of the main cylinder) to the action of
the products of combustion passing in the reverse direction as indicated by the
arrows. Air may be supplied as explained with regard to Figure 2 by pas-
sages j.
The supply of lime to the revivifying apparatus, described with regard to Figures
2, 3, 4, 5, 6, and 7, may be either intermittent or continuous; in the latter case the
apparatus is preferably fitted with feeding rollers, screw feelers, or other equivalent,
which arrangements are well understood, and are consequently not shewn in the
Drawing.
The interiors of the cylinders or chambers of the various arrangements may be
plain, as shewn in the transverse section Figure 8, or they may have formed therein
continuous or discontinuous ribs, either spirally or longitudinally disposed, as illus-
trated in the transverse section, Figure 9, for the purpose of more thoroughly turning
over the lime and regulating its delivery through the said cylinders or chambers
whilst undergoing revivification. These ribs also have the effect of exposing a
larger surface of the lime to the action of the revivifying gases.
The guides for supporting the cylinders or chambers of the various arrangements
are furnished with antifriction rollers for the ribs of the said cylinders to bear and
rotate upon with as little friction as possible. A suitable form of guide is represented
in side elevation in Figure 11, where the antifriction rollers are marked n, n, and in
constructing the apparatus sufficient clearance must be left between the stationary
walls and the rotating parts, to allow of the several parts expanding when heated, as
is well understood by practical men.
A jet of steam may be used to assist the products of combustion in their revivi-
fying action, the said steam being preferably injected at the lower end of the cylinder.
or series of cylinders or chambers, or into the furnace. In the Darwings of the
various arrangements steam pipes for this purpose, marked k, k, are shewn
The cylinders may be rotated by other means than those shewn, or they may
receive slow oscillatory or swinging motion in place of a rotating motion, the said
oscillatory motion being obtained by any suitable or well-known arrangements for
effecting such motion.
Although the cylinders or chambers are represented in the Drawings, as being of
a circular figure in cross section, yet they may have any other desired or convenient
form. Figure 10 is a transverse section of a chamber of an elliptical form, which

page_text: form is more especially suited for use where an oscillatory motion is employed in
place of a rotary motion.
Instead of the cylinders or chambers communicating with a chimney the said
cylinders or chambers may be in communication at their upper end with an
exhauster when it is desired to collect the gaseous or condensible substances passing
off or produced by the action of the fire gases or steam upon the foul lime.
Having now described and particularly ascertained the nature of our said Inven-
tion, and the system, mode, or inauner in or under which the same is or may be used
or practically carried into effect, we would observe in conclusion that what we
consider to be novel and original and therefore claim as the Invention secured to us
by the herein-before in part recited Letters Patent is, the arrangements of appa-
ratus herein-before described (and illustrated in the four accompanying Sheets of
Drawings), or their equivalents for effecting the revivification of spent lime either
by intermittent or continuous operation, that is to say, apparatus in which the said
lime is submitted, in revolving or oscillating chambers, to the direct action of the
products of combustion from a furnace (assisted or not by steam), the said products
passing in one direction, whilst the lime under treatment travels in the reverse
direction.
In witness whereof, I, the said George Robertson Hislop, have hereunto set my
hand and seal, this Fourteenth day of October, in the year of our Lord
One thousand eight hundred and seventy-eight.