IMPROVEMENTS IN AND MACHINERY FOR SCREENING LIME IN THE MANU- FACTURE OF BLEACHING POWDER
Year: 1877

page_text: LETTERS PATENT to Noah Greening and John Greening, both of Warrington,
in the County of Lancaster, Wire Manufacturers, for the Invention of
"IMPROVEMENTS IN AND MACHINERY FOR SCREENING LIME IN THE MANU-
FACTURE OF BLEACHING POWDER."
Sealed the 20th October 1877, and dated the 25th April 1877.
PROVISIONAL SPECIFICATION left by the said Noah Greening and John
Greening at the Office of the Commissioners of Patents on the 25th April
1877.
NOAH GREENING and JOHN GREENING, both of Warrington, in the County of Lan-
caster, Wire Manufacturers. "IMPROVEMENTS IN AND MACHINERY FOR SCREENING
LIME IN THE MANUFACTURE OF BLEACHING POWDER."
We take the fallen or slaked lime and throw it upon a screen as heretofore, but of
a considerably wider mesh, and arrange this screen to lead the line which passes
through directly and immediately into a stationary inclined cylindrical or conical
screen having revolving beaters mounted within it, and revolving at or about 300
revolutions per minute, more or less, the object of this cylindrical screening being
to act upon the lumps of lime as they come mixed with the powdered lime and
carbonate of lime from the inclined screen, and to break up such of the lumps as
are of a friable nature and consisting for the most part of pure lime.
The carbonate of lime and other hard substances which will not yield to the
disintegrating action of the beaters passing on through the cylindrical screen, and
making their escape through an opening at the lower end. By thus making the
first screen of considerably larger mesh and treating the material which passes
through as aforesaid, we are enabled to effect a considerable saving of lime which
has hitherto passed away as refuse at the first screening.
The powdered lime passed through the cylindrical screen is then raised by
elevators and submitted to the ordinary screening process previous to being intro-
duced into the chlorine gas chambers.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Noah Greening and John Greening in the Great Seal Patent Office on
the 25th October 1877.
NOAH GREENING and JOHN GREENING, both of Warrington, in the County of Lan-
caster, Wire Manufacturers. "IMPROVEMENTS IN AND MACHINERY FOR SCREENING 5
LIME IN THE MANUFACTURE OF BLEACHING POWDER."
Fig. 1 is a front sectional view, and Fig. 2 a side view of our improved mechanism
for screening lime, and Fig. 3 a plan view of the conical screen employed in the
same.
In all the views A is the ordinary screen upon which the slaked lime is thrown,
but which is constructed with a considerably wider mesh than heretofore, say with
interstices 3/4ths of an inch wide. This screen A is provided on its under side with
a shoot B, which leads the lime through a hopper C directly and immediately into
the interior of the conical screen D. This conical screen D forms an important
feature in our Invention, and consists of a wire-work stationary frame D¹, having a
shaft E passing horizontally through and working in bearings F, as illustrated.
Upon this shaft are mounted three or more iron blades or beaters G, which are
caused to revolve with the shaft by means of the strap H (passing round the
pulleys I and J respectively), at a rate of about 350 revolutions per minute, more
or less. The conical screen D is by preference situated at or near the bottom of the
framework K of the ordinary can or bucket elevators, and is surrounded on the
outside by a casing L, which prevents the dust and lime flying out, and which leads
the same to the trough K¹ of the bucket elevators L³.
The action of this improved screening apparatus is as follows:- -We take the
fallen or slaked lime and throw it upon the screen A as heretofore, the lime which
then passes through is led by means of the shoot B into the interior of the conical
screen D, where it is acted upon by the revolving beaters. The object of these
beaters being to act upon the lumps of lime as they come mixed with the powdered
lime and carbonate of lime from the inclined screen A, and so break up such of the
lumps as are of a friable nature and consisting for the most part of pure lime.
The carbonate of lime and other hard substances which will not yield to the
disintegrating action of the beaters G passing on through the conical screen and
making their escape through an opening M at the lower end. By thus making the
first screen of considerable larger mesh than heretofore and treating the material
which passes through as aforesaid, we are enabled to effect a considerable saving of
lime, which has hitherto passed away as refuse at the first screening.
The powdered lime passing through wire-work D¹ of the conical screen is then
raised by cams or elevators N and submitted to the ordinary screening process
previous to being introduced into the chlorine gas chambers.
Although we have only shewn a conical-shaped screen it will be apparent that a
cylindrical or other suitable form might be employed, the revolving beaters being
modified accordingly.
Having thus particularly described and ascertained the nature of this our said
Invention, together with the best methods with which we are acquainted for carrying
the same into practical effect, we wish it to be understood that we do not confine
ourselves to the precise details, relative proportions, or dimensions of the various
parts of the apparatus herein-before described and illustrated on the accompanying
Drawing, as the same may be considerably varied without departing from the
Invention; but what we claim is,-
1st. The improved method of treating lime as and for the purpose herein-before
described or any mere modification of the same.
2nd. The use and application of a conical or other suitably shaped screen provided

page_text: with revolving beaters, substantially as and for the purpose herein-before described
and illustrated on the accompanying Drawing.
In witness whereof, I, the said Noah Greening, for and on behalf of myself
and the said John Greening, have hereunto set my hand and seal, this
23rd day of October, in the year of our Lord One thousand eight hundred
and seventy-seven.
Witness,
JOHN G. WILSON,
Patent Office.
71, Market Street,
Manchester.
NOAH GREENING. (LS.)