IMPROVEMENTS IN FILTERS
Year: 1877

page_text: LETTERS PATENT to Edward Perrett, of 23, Abingdon Street, Westminster,
Civil Engineer, for the Invention of "IMPROVEMENTS IN FILTERS."
Sealed the 13th July 1877. and dated the 7th February 1877.
PROVISIONAL SPECIFICATION left by the said Edward Perrott at the
Office of the Commissioners of Patents on the 7th February 1877.
EDWARD PERRETT, of 23, Abingdon Street, Westminster, Civil Engineer "IM-
PROVEMENTS IN FILTERS'
This Invention has for its object improvements in filters
In the Specification of a former Patent granted to me No 2060, in the year 1874,
I have described a filter consisting of a drum covered with a filtering fabric and
contuned within a eistern to which the liquid to be filtered is admitted The
liquid filters through the filtering medium into the interior of the drum, from whence
by suitable means it is drawn off When the filtering medium became choked it
was proposed that the cistern should be emptied and the dium rapidly rotated
whilst a spray is admitted to the interior By this means the dirt was for the most
part thrown off, and the filtering medium rendered fit to be again used
Oi in
some cases the filtering drum, when it required cleaning, was taken away to another
and distinct machine in which it was 1otated for the purpose of cleaning it. Both
of these methods are in some cases attended with inconvenienco
According to my present Invention I do not empty the cistein when the filtering
medium requires to be cleaned, but I so arrange the apparatus that it can be raised
above the level of the liquid in the cistern and then iotated. The filtering drum
when raised occupies the upper part of the cistein, and the dut thrown off from it
by centrifugal action strikes against the sides and uns down into a gutter, which
intercepts it, leading it to a spout and preventing it passing into the liquid in the
lower part of the cistern
In order to obtain a larger filtering surface within a given space than a drum of
cylindrical form presents, I make the drum (if so it may still be called) of a series
of lenticular chambers having a cominon axis, and communicating the one with the
other The filtering fabric is made into a cylindrical bag of a length considerably
greater than the height of the drum The fabric enters the hollows between the
lenticular chambers from which the drum is built up.

page_text: In the operation of cleaning the filtering medium I sometimes apply a spray in
conjunction with the interior spray, or alone on the exterior surface of the dium by
means of a perforated pipe provided for the purpose
This I find in some cases
simpler than to apply the spray on the interior, for in the latter case unless care be
exercised in admitting the water the bag will be injured
In some cases I arrange the axis of the drum to pass through a stuffing box in
the bottom of the cistern, and being hollow it serves as the outlet for the filtered
liquid Or I support the axis of the dium at its lower end in a footstep on a bai
which can be raised by screws or otherwise, and when this footstep is inside the
cistern the outlet is by means of a flexible pipe in connection with the footstep.
SPECIFICATION in puisance of the conditions of the Letters Patent, filed by
the sud Edward Per ett in the Great Seal Patent Office on the 4th August
1877.
'
EDWARD PERRETT, of 23, Abingdon-Street,-Westminster, Civil Engineer. "IM-
PROVEMENTS IN FILTERS"
This Invention has for its object improvements in filters ·
In the Specification of a former Patent granted to me, No. 2060), in the year
1874, I have described a filter consisting of a dium covered with a filtering fabric
and contained within a cistern to which the liquid to be filtered is admitted Tho
liquid filters through the filtering medium into the interior of the dium, fiom
whence by suitable means it is diawn off When the filtering medium became
choked it was proposed that the cistein should be emptied and the diuin rapidly
1otated whilst a spray is admitted to the interioi By means the dut was for
the most part thrown off and the filtering medium rendered fit to be again used.
Or in some cases the filtering dium, when it requied cleaning, was taken away to
another and distinct machine in which it was 1otated for the purpose of cleaning it
Both of these methods are in some cases attended with inconvenience
According to my present Invention I do not empty the cistein when the filtering
medium eques to be cleaned, but I so aange the apparatus that it can be
raised above the level of the liquid in the cistern and then rotated The filtering
dium when used occupies the upper part of the cistein, and the dirt thrown off
fiom it by centrifugal action strikes against the sides and runs down to a gutter,
which intercepts it, leading it to a spout and preventing it passing into the liquid
in the lower part of the cistern
In order to obtain a large filtering surface within a given space than a dium of
cylindrical form presents, I make the drum (if so it may still be called) of a series
of lenticular chambers having a common axis and communicating the one with the
othei The filtering fabric is made into a cylindrical bag of a length considerably
greater than the height of the diuin The fabric enters the hollows between the
lenticular chambers from which the drum is built up
In the operation of cleaning the filtering medium I sometimes apply a splay in
conjunction with the interior spray, or alone on the exterior surface of the dium by
means of a porforated pipe provided for the purpose This I find in some cases
simple than to apply the spray on the interior, foi in the latter caso unless care be
exercised in admitting the water the bag will be injured
In some cases anange the axis of the drum to pass through a stuffing box in
the bottom of the cistern, and being hollow it serves as the outlet for the filtered
liquid Or I support the axis of the diuin at its lower end in a footstep on a bar
winch can be raised by screws or otherwise, and when this footstep is inside the
cistern the outlet is by means of a flexible pipe in connection with the footstep
In order that my said Invention may be most fully understood and readily
called into effect, I will proceod to describe the Diawings hereunto annexed.

page_text: DESCRIPTION OF THE DRAWINGS.
Figure 1 is a vertical section of a filter constructed according to my Invention;
Figure 1 is an horizontal section of the same taken on the line 1, 1, in Figure 1.
Figure 2 is also a vertical section of a filter constructed according to my Inven-
tion, but this filter differs somewhat in its details from the filter shown in Figure 1
a is the cistein in which the liquid to be filtered is contained, and to which the
liquid is supplied continuously or at short intervals as the filtering proceeds, b, b, is
the dium of the apparatus, it is composed of a series of lenticula chambers formed
of perforated sheet metal, they are mounted upon a hollow axis with which they
freely communicate The drum bis enclosed in a bag of filtering fabric which is
open at the onds, and is tied in around the axis by stings at the top and bottom
and also between the lenticular chambers The toc of the hollow axis has openings
it at c by which the filtered liquid passes into a cavity in the bearing in which
the axis of the drum is held, and from thence, according to Figure 1, the filtered
liquid is led by a flexible pipe d to a suitable receptacle
In the aangement shown in Figure 2 the filtered liquid escapes through the
tubee which is a prolongation of the hollow axis of the drum passing out of the
bottom of the cistein by a stuffing box. When it becomes necessary to clean the
filtering drum it is raised out of the liquid in the cistern a into an upper com-
partment, where it is rapidly rotated by a driving strap passing around the
pulley g
When by the rapid rotation the dirt is thrown off from the filtering
sui face it falls into the gutter which leads it to the spout, seen in Figure 2
For the purpose of using the filter dium, according to the anangement shown in
Figure 1, two screws 1, h, are employed, they are rotated simultaneously from a
hand wheel by means of the bevilled gear The support which receives the toe of
the hollow axis of the filtering dium is formed at its ends with nuts m, m, and the
screws,, work through these nuts, and in this way the filtering drum is raised
until the neck or upper end of the axis of the dium enters the opening in the centre
of the pulley g, and a feather within the pulley engages with a groove formed for it
in the neck
In the mangement shown in Figure 2 the neck of the axis is made much longer,
as 19 shown at n, and it has a screw thread cut upon it on which the hand nut o
works, so that on tuining the nut the dium is raised or lowered For 1otating the
dium the hand nut o is made fast by means of a screw to the pulley g.
Having thus described the nature of my said Invention, and the manner of per-
forming the same, I would have it understood that I claim,-
Fust. The construction of filters in such manner that the filterung dium may,
without removing it from the machine, bo lifted out of the liquid in the cistern and
then 1apidly 10tated so as to throw off the solid matter adhering to its exterior,
substantially as described
Second The construction of filters with the filtering drum composed of a series of
perforated lenticular chambers enclosed in a loosely fitting bag of filtering fabric,
substantially as described.
Thud The construction of filters, substantially as described and illustrated by
the annexed Diawings.
In witness whereof, I, the said Edward Perrott, have hereunto set my hand
and seal, this Thud day of August, in the year of our Lord One thousand
EDWARD PERRETT. (LS.)