ARDANGEMENT OF BAG FILTERS.
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
ARDANGEMENT OF BAG FILTERS.".
PROVISIONAL SPECIFICATION left by the said Edward o
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 THE ARRANGEMENT OF BAG
FILTERS," to be as follows:-
This Invention has for its object improvements in the arrangement of
bag filters used for the removal of matters in suspension in liquids.
After a time such bags become choked with the impuritics deposited
within them, and they cease to filter. When this happens the present
practice is to remove the bags in order to wash them. To avoid this
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page_text: labor and inconvenience I arrange the apparatus in such a way that
the bags may be cleansed by causing currents of liquid to pass through
the bags without removing them from their places. These currents of
liquid carry away the matters contained in the bags and cleanse them
so that they will filter a very large quantity of liquid before it becomes
necessary to remove them for a more thorough cleansing. To effect this
object I use bags open at the bottom as well as at the top. A bell
similar to that usually placed at the upper end of the bag, and to which
the bag is fixed; is inserted into the lower end. The lower bell is pro-
vided with a cock connecting with a reservoir to receive the contents of
the bag. When the bag ceases or partially ceases to filter on account
of the accumulation of dirt the cock at the bottom is opened, the matters
in suspension are swept out, and the rush of liquid through the bag
partly cleanses it, so that as soon as the cock is closed it recommences
to filter.
Instead of a separate cock to each bag several bags may communicate
with a common chamber at the lower end, and by opening a large cock
in this chamber all the bags may be blown through and cleansed at one
time.
SPECIFICATION in pursuance of the conditions of the Letters Patent,,
filed by the said Edward Perrett in the Great Seal Patent Office on
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, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth day of June, in the year of
our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Edward Perrett, Her special
license that I, the said Edward Perrett, 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

page_text: vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE ARRANGEMENT OF BAG FILTERS," 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
scals, 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 has for its object improvements in the arrangement of
bag filters used for the removal of matters in suspension in liquids.
After a time such bags become choked with the impurities deposited
within them, and they cease to filter. When this happens the present
practice is to remove the bags in order to wash them. To avoid the
labor and inconvenience I arrange the apparatus in such a way that the
bags may be cleansed by causing currents of liquid to pass through
the bags without removing them from their places. These currents of
liquid carry away the matters contained in the bags and cleanse them,
so that they will filter a very large quantity of liquid before it becomes
necessary to remove them for a more thorough cleansing. To effect
this object I use bags open at the bottom as well as at the top. A
bell similar to that usually placed at the upper end of the bag, and to
which the bag is fixed, is inserted into the lower end. The lower bell is
provided with a cock connecting with a reservoir to receive the contents
of the bag. When the bag ceases or partially ceases to filter on account
of the accumulation of dirt the cock at the bottom is opened, the
matters in suspension are swept out, and the rush of liquid through the
bag partly cleanses it, so that as soon as the cock is closed it recom.
mences to filter.
Instead of a separate cock to each bag several bags may communicate
with a common chamber at the lower end, and by opening a large cock
in this chamber all the bags may be blown through and cleansed at onc
time.

page_text: Figure 1 is a side elevation, and Figure 2 is an end elevation, both
partly in section, of three groups of bag filters arranged according to
my Invention, and in the manner which I prefer.
a, a, are cisterns for the unfiltered liquid; they have outlets from their
bottoms to which the filter bags b, b, are attached in the usual way;
c, c, are tanks to receive the filtered liquid; and the filter bags in place
of being closed at their lower ends, are connected with bells similar to
those at their upper ends, and thus the bags are put into communication
with small closed receivers d beneath the bottoms of the tanks c.
Each receiver d is fitted with a valve e, which is opened from time
to time to discharge the solid matter separated from the liquid. A
rapid flow of liquid then takes place through the bags from end to end
which sweeps away before it much of the deposited matter. The outlets
at the bottom of the bags also serve, even when the valves e are closed,
for the escape, by simple subsidence of the heavier impurities from the
bags into the receivers d.
What I claim is, the arrangement of bag filters with outlets for the
impurities at the lower ends of the bags, substantially as described.
I also claim the arrangement of bag filters so that the impurities may
be swept out at intervals by a rapid flow of liquid passed through them.
from end to end, substantially as described.
In witness whereof, I, the said Edward Perrett, have hercunto
set my hand and seal, this Tenth day of December, in the
year of our Lord One thousand eight hundred and seventy-
: four.
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