Improvements in the Method of and Apparatus for Filtering, Washing, and Drying Crystalline, Granular, and other Materials.
Year: 1896

page_text: Date of Application, 10th Dec., 1896
Complete Specification Left, 9th Sept., 1897-Accepted, 30th Oct., 1897
PROVISIONAL SPECIFICATION.
Improvements in the Method of and Apparatus for Filtering, Washing,
and Drying Crystalline, Granular, and other Materials.
We, SAMUEL SHERRATT and WILLIAM ARMSTRONG RICHARDS, Engineers, both
with Messrs. Brunner, Mond & Co. Ld. of Northwich in the County of Chester do.
hereby declare the nature of this invention to be as follows:-
This invention has for its object a method of and devices applicable for filtering,
washing and drying crystalline, granular, or other materials and for automatically
emptying the filter. The filter is preferably made to rotate, but can be stationary.
if desirable, except during the operation of emptying. It is formed of a round
vessel with sloping sides down to the filter bed, which latter is formed of any usual
material, the filtering material not being a new part of the present invention.
This is provided with a mechanical discharging apparatus and may comprise a
series of curved ploughs or scrapers, fitted to the apparatus and suspended above,
the vessel, one delivering to the other, and capable of being raised and lowered
by hand or by automatic machinery, but otherwise held stationary. These
ploughs or scrapers do not by preference turn with the filter but rise or descend
when required. The united scrapers practically form a volute curve, which, when
the scraper is gradually lowered down nearly to the filter bed, scrapes the material
out and delivers it to the side. The raising and lowering mechanism can be
worked by hand, or. by machinery, and by means of cams, cranks or the like, it
can have a slow descent, a quick ascent, and a period of rest. It is preferably
Counter-weighted so as to avoid undue strain on the mechanism. The space below
the filter bed is cut off from the atmosphere, and delivers into a vacuum chamber
either directly or through pipes. A central pipe well shielded, passes up into a
chamber below the filter bed, so as to produce a vacuum below the filter bed,
independent of the vacuum chamber. A further pipe connected with the air pump
or its equivalent withdraws gas and vapour from near the top of the vacuum
chamber. A pipe or pipes, leading from the chamber below the filter bed passing
through and down below the vacuum chamber, deliver the filtered liquid through
upward branches or otherwise into the vacuum chamber, when it may be dealt
with as required. The liquid can be withdrawn from this chamber by a suitable
pipe. The vacuum chamber may or may not rotate with the filter, preferably not.
If it does not rotate, then the filter and its appurtenances are so arranged that they
can rotate independently of the vacuum chamber.
In operation, the filter vessel, while turning on its centre, is filled with the liquid
to be treated, the vacuum chamber being under vacuum. By this means the solid
matter is evenly deposited on the surface of the filtering medium when it can be
washed if necessary by a hose or other well known means, and dried, while the
filtered liquid is drawn through the pipes into the vacuum chamber when it may
be dealt with as required. The vacuum pipe is introduced through the pipe which
leads the filtered liquid from the filter vessel and is protected with a shield to avoid
splashing. When desired, the discharging apparatus is set in motion and the

page_text: ploughs descend vertically. In this way the solid matter is gradually ploughed up
and forced in along the outside of the ploughs and ejected over the revolving
vessel. The depth to which the ploughs descend is regulated by a crank
which has a reciprocal and not a rotary motion, so that these ploughs cannot
descend lower than required, and they rise automatically leaving the filter ready 5
for another operation.
Dated this 9th day of December 1896
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicants.
Improvements in the Method of and Apparatus for Filtering, Washing,
and Drying Crystalline, Granular, and other Materials.
We, SAMUEL SHERRATT and WILLIAM ARMSTRONG RICHARDS, Engineers, both
with Messrs. Brunner, Mond & Co. Ld. of Northwich in the County of Chester, do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
This invention has for its object a method of and apparatus applicable for
filtering, washing and drying crystalline granular or other material and for
automatically emptying the filter.
The invention is best described by aid of the accompanying drawings, in which,
Figure 1 is a vertical section of the apparatus;
Figure 2 a plan of same;
In these, A is a circular vessel having sloping slides down to the filter bed B.
This latter is formed of any suitable material, the nature of the filtering material
not forming any novel part of the present invention. C C C are mechanical
discharging blades, ploughs or scrapers curved in contour and so contrived as to
form a practically continuous volute from the centre to the outside. The outer
blade C has its end bevelled to suit the contour of the sides of the revolving
vessel A and has its outer end hinged to a fixed point as at C. These scrapers,
counterbalanced by counterweights E are raised and lowered by means of bell
cranks Dattached to horizontal shaft E having a reciprocal motion only, which
shaft is set in motion when it is desired to empty the filter. Any convenient
mechanism can be attached to this shaft to bring it into action when required.
Fis a spout down which the material to be filtered is passed into chamber A. This
spout is so arranged as to distribute the material to be filtered along one radius of
the circular vessel A by which means the filter is uniformly filled. G is a tubular
continuation of chamber A, and H an impervious bottom surrounding the mouth
of this tubular continuation. I is a tube connecting the space below the filter bed
of chamber A with a vacuum pipe J connected with any suitable air pump or other
vacuum creating device. jis a branch vacuum pipe. The whole of the parts
ABG & H are caused to slowly rotate when required by a bevel wheel K and
suitable connecting gear. The tubular connection G is carried in bearings L, and
stuffing box N hereafter described. These are supported on a stationary vacuum
chamber M. m m are two tubes connecting the tubular connection L with the
vacuum chamber M by means of stuffing box N. P is a large tank into which the
chamber M can be emptied by means of pipe Q, which latter has in its course a
non-return clack valve q. The upper part of tank P is also connected with the
upper part of chamber M by means of pipe R having two valves is simply
a stop valve and ra three-way cock having an opening into the atmosphere.

page_text: When the handle is in one position both cocks are, opened, turned so as to form a
continuous passage from chamber M to tank 1', but closing the opening to the air.
When the handle is in the other position the cock r is closed and the lower cock r
connects tank P with the atmosphere, the vacuum in it is destroyed and the liquor
in the tank can be run off through a suitable discharge, cock, the non-return clack
valve 9 preventing air from tank P entering the vacuum chamber M.
The mode of operation is as follows:-
The material to be filtered, washed and dried is from time to time discharged
into the filtering chamber A on to the filtering bed B. A vacuum is formed in the
chamber below the filtering bed and the liquid, very rapidly passes into said
chamber and thence through the continuation pipe G into the vacuum chamber M.
Any washing fluid necessary is then added in a similar way to the material under
treatment, that is along one radius of the circular vessel A. None of the liquid
however can pass into the vacuum pipe J owing to the cover over the pipe I and
the other pipe opening out only into the very top of chamber M. As chamber M
fills and before it can reach to the mouth of pipe the cocks and rare
opened. This brings the vacuum chamber M and the tank P' to the same
pressure and the liquid in chamber M passes down the pipe Q through the back
pressure valve q into the tank P. When the tank. P is required to be discharged
the cocks and r¹ are placed in the other position. Air enters and destroys the
vacuum in tank P. Back pressure valve 7 comes into operation and cuts off the
remaining connection with vacuum chamber M and the tank P can now be dis-
charged by gravity from any suitable pipe at the bottom. When the material on
the filter B has been sufficiently washed and dried, the scrapers C₁ C and C³ are
slowly lowered, ploughing or scraping the material off the filter bed B to the out-
side of the vessel A where it falls down any convenient spout not shown in the
drawings. The scrapers cannot descend to such a point as would bring them in
contact with the filter bed, the apparatus being so arranged as to allow of the
scrapers descending to within a certain distance only of the filter B to avoid risk
of damage to the filtering material, they then rise automatically and resume their
original position by the action of a crank, or eccentric, leaving the filter ready
for a fresh operation.
During the operation the vessel A has been rotated slowly by the spur gearing
The filtering apparatus is made to rotate and the scrapers to have a vertical
motion only instead of the filtering apparatus being stationary and the scrapers a
descending screw or rotary motion, as in this latter case the filtered and dried.
material would be delivered all round the circumference instead of at one fixed
point.
The apparatus can be used merely for filtration or for filtration and washing by
the contiuous or intermittent addition of hot and cold water or other washing
fluid; or for filtering, washing and afterwards drying, the latter action being
effected simply by drawing ordinary atmospheric air or other gas through the
material on the bed by means of vacuum, or specially dry cold or hot air or other
gas can be brought to the apparatus and passed through.
Having now particularly described and ascertained the nature of our, said
invention and in what manner the same is to be performed we declare that what
we claim is:-
1. The method of filtering, washing and of drying crystalline granular and other
like materials, which consists of discharging the said materials on a rotating filter-
ing bed with or without the addition of water or other washing fluid, and drawing
the liquid, and, if the material requires to be dried subsequently, air or gas also
heated or otherwise, through the material on the filter bed by means of vacuum
substantially as described.
2. The combination with a filter bed and a filtering and washing device for
treating crystalline granular or other material by means of difference of pressure
above and below the filter bed, of a scraping device capable of being automatically

page_text: or by hand lowered on to the bed and means for producing a rotary relative motion,
between the filter bed and the scraping device during such lowering, substantially
as described.
3. The apparatus for filtering, washing and drying and mechanically discharg-
ing crystalline granular and other materials substantially as herein described and
illustrated.
Jon of Contamhan 1907
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Birmingham and London, Patent Agents.