IMPROVEMENTS IN SIEVES AND FILTERS
Year: 1873

page_text: LETTERS PATENT to Charles James Wahab, of Penicuick, in the
County of Mid Lothian, North Britain, Civil Engineer, for the
Invention of "IMPROVEMENTS IN SIEVES AND FILTERS,"
PROVISIONAL SPECIFICATION left by the said Charles James Wahab
at the Office of the Commissioners of Patents, with his Petition,
on the 12th August 1873.
I, CHARLES JAMES WAHAB, of Penionick, in the County of Mid
Lothian, North Britain, Civil Engineer, do hereby declare the nature
of the said Invention of "IMPROVEMENTS IN SIRVES AND FILTERS," to be
as follows, that is to say :-
This Invention relates to a new or improved sifting and filtering
apparatus, whereby the particles or bodies constituting any mass of one
or more substances may be sifted, separated, or assorted into as many
different sizes as may be desired, and also whereby suspended impurities
may
be extracted from water or other fluids,

page_text: The Invention consists in the application of a spiral blade or fan to
move the substances to be sifted or the fluids to be filtered over the
sifting or filtering media. This is effected by joining together by any
suitable fastening a series of discs or rings, or segments of dscs or rings
cut, stamped, or shaped out of any suitable material so as to form a
spiral blade or fan of any desired pitch. One such blade or fan may be
employed in each sifting or filtering apparatus, or two or other number
of them may be intertwisted one within the other for the purposes of
this Invention. The blade or fan may be attached at each end to a
plain ring or disc, and it may be further strengthened throughout its
length by means of ties or other supports, or by a central shaft passed
through it. Over the rings or discs and outer periphery of the blade
or fan the sifting or filtering medium composed of any suitable
recticulated, perforated, or porous material is fixed.
The sifting or
filtering medium may. if desired be made double either over the whole or
part of the apparatus, or it may be constructed in two, three, or more
successive layers, the spaces between which may be filled up with sand,
gravel, ashes, paper pulp, "half stuff," or other suitable materials. The
sifting or filtering medium may be constructed with fine reticulations or
perforations at one end of the blade or fan, the reticulations or
perforations becoming coarser towards the opposite end of it, each
successive section of the reticulations or perforations being formed of a
greater or lesser breadth, according to the purpose for which the
apparatus is to be employed.
The materials to be sifted or the fluid to lie filtered may be introduced
to the interior of the apparatus at one end by any suitable means, and
the apparatus being caused to rotate the said materials are thereby
gradually passed from one end of the apparatus to the other, during
which operation the particles or bodies constituting the mass fall
through the different sizes of reticulations or perforations, and are thus
sifted or assorted..
In some cases however it may be found advantageous to cause the
mass of the substances to be sifted, or of the fluids to be filtered to come
in contact with the outside of the apparatus so that the finer particles
will pass through the sifting or filtering medium, and be collected at
one end of the apparatus and the coarser ones rejected.
It is to be understood that I do not limit myself to either mode of
operating the sieve or filter herein-before described, neither do I limit

page_text: myself to using what is strictly speaking a blade or fan, as any other
means for obtaining one or more spiral projections at or near the
periphery of the apparatus is sufficient for the purposes of this
Invention.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles James Wahab in the Great Seal Patent
Office on the 10th February 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
JAMES WAHAB, of Penicuik, in the County of Mid Lothian, North
Britain, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twelfth day of August, in the year.
of our Lord One thousand eight hundred and seventy-three, in the
37th year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Charles James Wahab, Her special
license that I, the said Charles James Wahab, my executors, adminis-
trators, and assigns, or such others as I, the said Oharles James
Wahab, my executors, administrators, or assigns, should at any time
agree with, and no others, from time to time and at all times thereafter.
during the term therein expressed, should and lawfully might make,:
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN SIEVES AND FILTERS," upon the condition (amongst others)
that I, the said Charles James Wahab, by an instrument in writing
under my hand and seal, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great Seal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Charles James Wahab, do hereby
declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in
and by the following statement, reference being had to the accom-

page_text: to say :-
My said Invention relates to a new or improved sifting or filtering
apparatus, whereby the particles or bodies constituting any mass of one
or more substances may be sifted, separated, or assorted into as many
different sizes as may be desired, and also whereby suspended impurities
may be extracted from water or other fluids by filtration.
The Invention consists in the application of a spiral blade or fan to
move the substances to be sifted or the fluids to be filtered over the
sifting or filtering media. This is effected by joining together by any
suitable fastening a series of discs or rings or segments of discs or rings,
cut, stamped, or shaped out of any suitable material, so as to form a
spiral blade or fan of any required pitch. One such blade or fan may
be employed in cach sifting or filtering apparatus, or two or more of
them may be intertwisted one within the other for the purposes of this
Invention. The spiral blade or fan may be attached at each end to a
plain ring or disc, and it may be further strengthened throughout its
length by means of ties, stays, or other supports, or by a central shaft
passing through the apparatus. Over the outer periphery of the spiral
blade or fan, the sifting or filtering medium composed of any suitable
reticulated, perforated, or porous material is fixed. The sifting or
filtering medium may if desired be made double, either over the whole
or part of the apparatus, or it may be constructed in any number of
successive layers, the spaces between which may be filled up with sand,
gravel, ashes, paper pulp, "half stuff," or other suitable materials. The
sifting or filtering medium may be constructed with fine reticulations or
perforations at one end of the apparatus containing the spiral blade or
fan, these reticulations or perforations becoming coarser towards the
opposite end of the apparatus, each successive section of these
reticulations or perforations being formed of a greater or lesser breadth
according to the purposes for which the apparatus is to be employed.
The materials to be sifted or the fluids to be filtered may be introduced
to the interior of the apparatus at one end by any suitable means, and
the apparatus being caused to rotate the said materials or fluids are
gradually passed by the progressive or advancing action of the spiral
blade or fan over the sifting or filtering medium or media to the other
end of the apparatus. During this operation the particles or bodies

page_text: constituting the mass of the material fall through the different sizes of
reticulations or perforations, and are thus sifted or assorted, or the
fluid in passing through the filtering medium or media leaves thereon
whatever suspended impurities it may have held when introduced into
the apparatus.
In some cases however it may be found advantageous to cause the
mass of the substances to be sifted or of the fluids to be filtered to come
in contact with the outside of the apparatus, so that the finer particles
of the material or the purified fluid will pass through the sifting or
filtering medium and be collected at one end of the apparatus, while the.
coarser parts of the material or the suspended impurities of the fluid will
be rejected.
But it is to be understood that I do not limit myself to either mode
of operating the sieve or filter herein-before described; neither do I
limit myself to what is strictly speaking a blade or fan, as any other
means for obtaining mere spiral projections at or near the periphery
of the apparatus are sufficient for the purposes of this Invention.
And in order that my said Invention may be properly understood I
now proceed more particularly to describe or set forth the system, mode,
or manner in or under which the same is or may be used or practically
carried into effect, to be as follows, that is to say :-
On the Sheet of Drawings hereunto appended Figure 1 is an end
elevation of the apparatus to which my Invention is shewn applied;
Figure 2 is a side elevation at right angles to Figure 1. These Drawings
illustrate my Invention as applied to the sifting and assorting of loose
materials.
Through the hopper and duct A. the material is introduced into the
apparatus, which is mounted on standards or frames B, and is rotated
by a central driving shaft -0, which may be actuated manually through
an ordinary handle, or driven by means of the pulleys shewn fixed on
the end thereof. Upon either extremity of the shaft O and between the
standards or frames B, two rings or discs marked respectively D, E,
having radiating spokes are fixed. And between these rings or discs
and further secured in their position by stays or tie bars F are the spiral
blades or fans G. The sifting medium H is shewn stretched round the
periphery of the spiral blades or fans G. It will also be seen from the
Drawings that the sifting medium H is divided in its length into sections,

page_text: each section varying from the others in the size of the reticulations or
perforations, these being made fine where the material is introduced into
the apparatus through the hopper and duct A, and becoming coarser in
succession as they approach the other end, where another duct I receives
the refuse or that portion of the sifted material the parts of which are
too coarse to allow them to fall through the meshes, reticulations, or
perforations of the sifting medium H.
In operating the above described apparatus the material to be sifted is
thrown by any suitable means into the hopper and duct A, by which it
is transferred to the interior of the apparatus which is caused to rotate
slowly. The rotating of the apparatus besides sifting the material at
the same time causes it to be carried forward by the spiral blades or fans,
and it is thus passed through the whole length of the apparatus and over
the different sections of sifting media. The material thus operated
upon is not only sifted but is also assorted, each section of the sifting
medium forming a distinct heap the parts of which are practically alike
in size.
T
:
Instead of mounting the apparatus upon a central shaft the end rings
or discs may rest upon rollers, and thus allow the apparatus to rotate.
Having now described and particularly ascertained the nature of my
said Invention, and the system, mode, or manner in or under which the
same is or may be used or practically carried into effect, I would observe
in conclusion that what I consider to be novel and original, and there.
fore claim as the Invention secured to me by the herein-before in part
recited Letters Patent is, the novel arrangement of a rotating hollow
cylinder composed of a sifting or filtering medium with spiral blades,
fans, or projections to be used for sifting or filtering and assorting
materials or fluids as herein-before described.
In witness whereof, I, the said Charles James Wahab, have here-
unto set my hand and seal, this Seventh day of February,
One thousand eight hundred and seventy-four.
CHARLES JAMES WAHAB. (L.S.)