IMPROVEMENTS IN APPA- RATUS FOR FILTERING LIQUIDS
Year: 1879

page_text: LETTERS PATENT to Edward Perrett, of Victoria Chambers, in the City of
Westminster, Civil Engineer, for the Invention of "IMPROVEMENTS IN APPA-
RATUS FOR FILTERING LIQUIDS."
ealed the 25th July 1879, and dated the 27th January 1879
PROVISIONAL SPECIFICATION left by the said Edward Perrett at the Office
of the Commissioners of Patents on the 27th January 1879.
EDWARD PERRETT, of Victoria Chambers, in the City of Westminster, Civil
Engineer. "IMPROVEMENTS IN APPARATUS FOR FILTERING LIQUIDS."
This Invention relates partly to improvements upon the filtering apparatus for
which Letters Patent were granted to me on or about the 13th of June 1874,
No. 2060, & has for its object the increasing the efficiency of the filtering appa-
ratus by substituting a hollow cylindrical or other equivalent shaped block or mass
of filtering material, such, for example, as charcoal, sand, sponge, wool, and the like
placed inside the drum in lieu of using a mere bag of woven fabric, canvass, or wire
gauze stretched over or supported outside a drum or framing, as mentioned in the
Specification of my said former Patent.
The drum or framing containing or supporting the block or mass of filtering
material is mounted on a hollow & perforated spindle, & like the said spindle is
perforated or composed if preferred of wire work. The drum with its spindle is
placed within a casing or cistern, & is so arranged as to be capable of rapid
rotation therein. The liquid to be filtered is introduced into the space between the
said cistern & the drum, & passes inwards through the mass of filtering material,
the matters that were in suspension being left in the said material whilst the now
filtered liquid passes off through the hollow peforated spindle inside the drum.
When it is desired to clean the filtering material the liquid remaining in the
casing or cistern is drawn off, and a reverse current of clean liquid is introduced from
the inside of the spindle through the mass of filtering material to the outside of the
drum, which drum is at the same time caused to rotate rapidly, the combined
actions of the reverse currents with the revolutions of the drum causing the dirt to
be rapidly carried outwards & thrown into the casing, whence it flows off, leaving
the mass of filtering material ready to recommence the operation of filtering. In
some cases the lower end of the spindles is prolonged, & formed with spiral
openings somewhat after the fashion of a turbine, such portion revolving submerged

page_text: in a cistern, so that the revolutions shall cause a sufficient quantity of liquid neces-
sary for the reverse current-to-be-elevated-without-further appliances..
In those cases where-compressed filtering material is used it may be found
desirable to release or slacken the compression slightly before the rotation of the
_filter for cleaning.
According to another construction of filter; wherein rotation--thereof_for_the
purpose of cleaning is obviated, the tank or vessel containing the compressible
filtering material always remains stationary. It is provided with a perforated-false-
-bottom & perforated diaphragm near the top, also with a moveable perforated
piston about midway between the false bottom & perforated diaphragmı.
The filtering material, which by preference should be capable of compression &
expansion, such, for example, as sponge, is placed either above or below the piston
or its mechanical equivalent, or both above & below the said piston. The said
piston is raised & lowered by a screw or other equivalent, as is also the upper or
lower or both diaphragms, so as to compress the filtering material between them.
The liquid to be filtered is passed through the compressed filtering material, & flows
off either at the top or bottom of the tank. In order to clean the said filtering
material one or both the diaphragms are slackened out so as to afford space for the
expansion of the filtering material & for the piston to move between the diaphragms.
By alternately raising & lowering the piston the filtering material will be alternately
compressed & released, a current of liquid being caused at the same time to flow
through the filtering material thereof, carrying off any impurities lodged in the said
material and disturbed by the action of the piston.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Perrett in the Great Seal-Patent Office-on-the.25th July
1879.
EDWARD PERRETT, of Victoria Chambers; in the City of Westminster, Civil
Engineer. "IMPROVEMENTS IN APPARATUS FOR FILTERING LIQUIDS."
My said Invention relates partly to improvements upon the filtering apparatus
for which Letters Patent were granted to me on or about the 13th of June 1874,
No. 2060, and has for its object the increasing the efficiency of the filtering appa-
ratus by substituting a hollow cylindrical or other equivalent shaped block or mass
of filtering material, such, for example, as charcoal, sand, sponge, wool, and the like,
placed inside the drum in lieu of using a mere bag of woven fabric, canvass, or wire
gauze stretched over or supported outside a drum or framing as inentioned in the
Specification of my said former Patent.
The drum or framing containing or supporting the block or mass of filtering
material is mounted on a hollow and perforated spindle, and like the said spindle is
perforated or composed if preferred of wire work. The drum with its spindle is
placed within a casing or cistern, and is so arranged as to be capable of rapid

page_text: rotation therein. The liquid to be filtered is introduced into the space between the
said cistern and the drum, and passes inwards through the mass of filtering material,
the matters that were in suspension being left in the said material, whilst the now
filtered liquid passes off through the hollow perforated spindle inside the drum.
When it is desired to clean the filtering material; the liquid remaining in the
outer casing or cistern is drawn off, and a reverse current of clean liquid is intro-
duced from the inside of the spindle through the mass of filtering material to the
outside of the drum, which drum is at the same time caused to rotate rapidly, the
combined actions of the reverse currents with the revolutions of the drum causing
the dirt to be rapidly carried outwards and thrown into the casing, whence it flows off,
leaving the mass of filtering material ready to recommence the operation of filtering.
In some cases the lower end of the spindle may be prolonged and formed with spiral
openings somewhat after the fashion of a turbine, such portion revolving submerged
in a cistern, so that the revolutions shall cause a sufficient quantity of liquid neces-
sary for the reverse current to be elevated without further appliances.
In those cases where compressed filtering material is used it may be found
desirable to release or slacken the compression slightly before the rotation of the
filter for cleaning.
According to another construction of filter, wherein rotation thereof for the
purpose of cleaning is obvinted, the tank or vessel containing the compressible
filtering material always remains stationary. It is provided with a perforated
false bottom and perforated diaphragm hear the top, also with a moveable perforated
piston about midway between the false bottom and perforated diaphragm.
The filtering material, which by preference should be capable of compression and
expansion, such, for example, as sponge, is placed either above or below the piston
or its mechanical equivalent, or both above and below it. The said piston is raised
and lowered by a screw or otherwise, as is also the upper or lower or both
diaphragms, so as to compress the filtering material between them. The liquid to
be filtered is passed through the compressed filtering material, and flows off either
at the top or bottom of the tank. In order to clean the said filtering material
one or both the diaphragms are slackened out so as to afford space for the expansion
of the filtering material, and for the piston to move between the diaphragms. I
prefer, for simplicity, to employ merely an adjustable perforated diaphragm on the
top of the filtering material, and a reciprocating perforated piston beneath the
same, the filtering material being disposed between the two. By alternately
raising and lowering the piston by the aid of cranks or otherwise, the filtering
material will be alternately compressed and released, a current of liquid being
caused at the same time to flow through the filtering material thereof, carrying off any
impurities lodged in the said material and disturbed by the action of the piston.
And in order that my said Invention may be fully understood I shall now proceed
more particularly to describe the same, and for that purpose shall refer to the
Figures on the annexed Sheet of Drawings.
Figure 1 of my Drawings illustrates the first form of filter hereinbefore referred
to. a is the perforated drum; a¹ is an inner perforated drum; b is the filtering
material; c is the hollow perforated spindle; d is a gland; e is the toe bearing of
the spindle contained within the box f; g is the tank with cover and gland h; i is
the driving pulley; k is the inlet for the unfiltered liquid; is the cutlet for the
filtered liquid, and also the inlet for cleansing water; m is the washout.
The mode of operation is as follows:-The drum a, a², remains stationary during
the operation of filtration, and the liquid to be filtered is brought into the tank g,
and passes through the filtering material therein, leaving all matters in suspension; it
finally finds an exit by the hollow spindle c to the outlet L. When the material
becomes choked, and it is desired to clean it, the supply is stopped, the washout m
opened, the cage or drum is rapidly rotated, and at the same time à reverse current of
liquid is introduced through the spindle which finds its way through the filtering
material into the tank, carrying the dirt with it to the washout. The filtering
material being thus cleaned is ready to recommence filtration.

page_text: Figure 2 illustrates an arrangement for the second form of filter herein before
referred to.
a is the tank; b, a perforated piston; c, the filtering material; d, the perforated
diaphragm is a screw with hand wheelf; g, g, are rods to the piston; h, h, are
connecting rods; i, i, are cranks on a shaft working in bearings k, k; l is a driving
pulley-m-the-inlet-for-unfiltered liquid; n is the outlet for filtered--liquid; o is
the washout.
This apparatus is-worked-as-follows:-The piston_b being set at its highest
position by means of the cranks i, i, the diaphragm d is screwed down, and the
filtering material c is thus compressed between them. The liquid to be filtered is
brought in at m below the piston, and passing upwards through the material c finds
an exit by the outlet n. When the filtering material is choked, and it is desired to
clean it the supply is stopped, the washout o opened, the diaphragm d is raised, and
the cranks rotated, thus raising and lowering the piston b; at the same time a reverse
current of liquid is brought into the casing over the filtering material, which carries
away the impurities disturbed by the action of the piston.
Having now described and particularly ascertained the nature of my said Inven-
tion, and the manner in which the same is or may be used or carried into effect, I
would observe in conclusion that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the herein before in part recited
Letters Patent is,―
First. The construction and use of a filtering apparatus arranged substantially as
herein before described, in which a reverse current of liquid in conjunction with
centrifugal action is employed for cleaning the mass of filtering material.
Second. The construction and use of filtering apparatus arranged substantially as
herein before described, in which a reverse current of liquid in conjunction with the
movement of a piston is employed for cleaning the mass of filtering material.
Third. The construction and arrangement of filtering apparatus and the means of
cleaning the mass of filtering material contained therein, substantially as herein-
before described, and illustrated by my Drawings.
In witness whereof, I, the said Edward Perrett, have hereunto set my hand
and seal, this Twenty third day of July, in the year of our Lord One
thousand eight hundred and seventy nine.