IMPROVEMENTS IN APPARATUS FOR FILTERING LIQUIDS.
Year: 1874

page_text: LETTERS PATENT to Edward Perrett, of No. 6, Great George Street,
Westminster, in the County of Middlesex, Civil Engineer, for the
Invention of
66
IMPROVEMENTS IN APPARATUS FOR FILTERING LIQUIDS.´
PROVISIONAL SPECIFICATION left by the said Edward Perrett at the
Office of the Commissioners of Patents, with his Petition, on the
13th June 1874.
I, EDWARD PERRETT, of No. 6, Great George Street, Westminster,
in the County of Middlesex, Civil Engineer, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN Apparatus for FilTERING
LIQUIDS," to be as follows:-
This Invention relates to an apparatus for filtering liquids, and the
means of readily cleaning such apparatus for repeated use. I take
canvas, wire gauze, or other suitable filtering material, and form it into.

page_text: a cylindrical shape, supporting it by a frame or otherwise. The cylinder
is put into a tank containing the liquid to be filtered, and the liquid
passes into the inside in a filtered condition and is drawn off, leaving the
matters that were suspended in the now filtered liquid adhering to the
outside of the filtering material.
In order that the filtering cylinder or bag may be readily cleansed I
so arrange it that a rapid rotatory motion may be given to it by external
means, or by placing a turbine or steam or water motor in the interior
of the cylinder or bag. The rapid rotatory motion causes the particles
adhering to the exterior of the cylinder to fly off; this action may
advantageously be assisted when external power is applied by the intro-
duction of a small quantity of liquid or steam into the cylinder whilst in
motion.
When a turbine is employed as the motor the water discharged by its
striking the interior of the cylinder or bag aids in removing the matter
deposited on its outer surface. The liquid is drawn off from around the
filter before the cleansing operation is commenced.
In some cases it will be found advisible to remove the cylinder from
the tank containing the filtering liquid to place it in another apparatus,
in which rotatory motion can be applied to. it. The rotatory machine
then serves to clean many bags in succession. This will be found an
especially advantageous arrangement in the case of filtering liquor in
sugar refining.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edward Perrett in the Great Seal Patent Office on 2
' the 11th December 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
PERRETT, of No. 6, Great George Street, Westminster, in the County
of Middlesex, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her 3
Letters Patent, bearing date the Thirteenth day of June, in the year

page_text: of our Lord One thousand cight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Edward Perrett, Her special license
that I, the said Edward Perrett, my executors, administrators, and
assigns, or such others as I, the said Edward Perrett, my executors,
administrators, and 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
APPARATUS FOR FILTERING LIQUIDS," upon the condition (amongst others)
that I, the said Edward Perrett, my executors or administrators, by
an instrument in writing under my, or their, or one of their hands and
seals, 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 Scal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Edward Perrett, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
This Invention relates to an apparatus for filtering liquids, and the
means of readily cleaning such apparatus for repeated use. I take
canvas, wire gauze, or other suitable filtering material, and form it into.
a cylindrical shape, supporting it by a frame or otherwise. The cylinder.
is put into a tank containing the liquid to be filtered, the liquid passes
into the inside in a filtered condition and is drawn off, leaving the
matters that were suspended in the now filtered liquid adhering to the
outside of the filtering material.
In order that the filtering cylinder or bag may be readily cleansed I-
so arrange it that a rapid rotatory motion may be given to it by external.
means, or by placing a turbine or steam or water motor in the interior
of the cylinder or bag. The rapid rotatory motion causes the particles
adhering to the exterior of the cylinder to fly off; this action may
advantageously be assisted when external power is applied by the intro-

page_text: of a filter arranged according to my Invention.
1
a is a case with a movable cover a¹ containing the skeleton drum b,
which is covered with a cylindrical bag of a filtering fabric, open at the
ends and drawn in over the ends of the drum by drawing strings; c is
the axis of the drum, which is hollow for the greater part of its length;
c¹, c', are passages leading into it; d, d, is an annular valve of india-
rubber able to close these passages; e, e, are curved hollow arms on the
axle c; fis the outlet from the case a.
The liquid to be filtered is let into the case a under pressure if desired,
and pressing on the filtering material supported by the skeleton drum 6
passes through it, leaving the matters in suspension on the outside of
the material, while the filtered liquor passes through the openings
c¹, c', into the hollow axis c, and so by the outlet pipe f to a proper
receptacle.
When it is desired to clean the filter the liquid between the filter and
case is drawn off, liquid or steam under pressure is admitted to the
pipe f, and by it to the hollow axis c (which with the filter frame is
capable of rotatory motion), the fluid forces up the valve. d, closes the

page_text: openings c¹, c', and passing through the curved arms e, e, causes a rapid
rotatory motion to be given to the filter, which throws off the scum and
dirt collected on the exterior. The dirt then falls down the sides to the
bottom, whence it is drawn off.
curved arms assists the cleansing action of the centrifugal force.
The liquid or steam issuing from the
Figure 3 is a sectional elevation of a filter, in which the power to
rotate it when it requires cleansing is applied by external means; a is
the filter case, into which the liquid to be filtered is placed; is the
filtering material, say of woven fabric, supported upon perforated metal;
c is the cone on which the filter is fixed; d is the shaft which carries
the cone; it is driven by the pulleys e, e; f is a siphon pipe with a self-
acting valve, by which the filtered liquor is drawn off from the interior
while the filter is at work; g is a sparger pipe, by which steam or water
is introduced to assist the cleansing by centrifugal action. In cleaning
the filter the liquid is drawn off from between the filter and the filter
case, a rapid rotatory motion is given to the filter, the dirt flies off, falls,
and is drawn off by the cock h.
Figure 4 is a sectional elevation of an arrangement to be used when
it is considered desirable to clean the filter in a separate tank to that
in which the filtering is performed; a is the filter, consisting of the
filtering material and supporting framework carried on a hollow spindle,
through which the filtered liquor escapes when the filter is in action, as
already described in respect to Figures 1 and 2; and when at work this
filter is mounted substantially as in these Figures. When it is desired
to clean the filter it is placed in a casing 6 and supported on a footstep c,
a sliding head d is then lowered to engage the hollow spindle, and 'by
means of the pulley e rapid rotatory motion is given to the filter, the
dirt flies off, and is drawn away as before. Liquid to assist the cleansing
can, if required, be introduced through the hollow pulley spindle f.
What I claim is the construction of apparatus for filtering liquids in
such manner that the filtering may take place from the exterior to the
interior of a cylinder or drum through the periphery, which is formed
of filtering material, and afterwards that the impurities deposited on the.
filtering material may be thrown off by rapidly rotating the drum,
substantially as herein described.

page_text: I also claim the combination of such filtering drums or cylinders with
turbines for the purpose of rapidly rotating them to throw off impurities,
substantially as described.
I also claim the construction of such filtering drums or cylinders so
that they may be removed from the filtering tanks and mounted in cases &
adapted to receive them, and there have rapid rotary motion imparted
to them to throw off impurities, substantially as described.
In witness whereof, I, the said Edward Perrett, have hereunto
set my hand and seal, this Tenth day of November, in the
year of our Lord. One thousand eight hundred and seventy- 1
four.