Improvements in Filtering Apparatus.
Year: 1896

page_text: Dite of Application, 28th May, 1396
Complete Specification Left. 1st Mar 1897-Accepted 1st May 1897
Improvements in Filtering Apparatus.
1, STANLEY KEMP WELCH of 1 Challoner Street, West Kensington in the
County of Middlesex, do hereby declare the nature of this invention to be as
follows:-
This invention relates to an apparatus for the rapid removal of solid matter
held in suspension in water or other fluid. especially those substances which settle
with difficulty, and which speedily choke ordinary filters.
The apparatus consists of a table or frame covered except round the edge with
perforated metal, wire work, or similar material. Beneath this surface is a shallow
chamber communicating with an air pump.
At each end of the table is a roller
over which, and resting on the table, is stretched a sheet of cloth or other filtering
material; the sheet passes underneath the table, and through a washing apparatus;
it is suitably guided and is preferably a continuous band, a portion being always in
contact, with the surface of the table.
Over the cloth an endless sheet of wire gauze or similar material is led for the
purpose of more easily removing the deposit.
A little above the table is suspended, or held in position, a frame of about the
same dimensions in length and breadth as the table; when lowered on to the
table it makes a tank, of which the bottom is formed by the cloth, or wire and
cloth.
The parts of the frame and of the table which come in contact are provided
with rubber rings or other packing to make a tight joint.
The mode of operation is as follows:-The frame having been lowered on to
the table, and a tank thus formed, the material to be filtered is run in. The air is
gradually exhausted from the space under the cloth and the pressure of the
atmosphere exerted on the surface of the liquid causes a rapid flow of the filtrate,
leaving the solid matters on the surface of the cloth. This flow will generally
slacken as soon as any considerable deposit forms on the cloth. If it be desirous
to obtain the deposit in as dry state as possible the flow of the liquid to be filtered
is stopped, any liquid remaining on the surface of the deposit is drawn off, and
the vacuum below is continued, as long as is found desirable, to consolidate the
deposit. If a great degree of solidification is desired the frame can be made
with a cover and compressed air may be introduced, thus subjecting the deposit to
any desired degree of pressure.
As soon as the deposit is sufficiently consolidated, or, if a solid deposit is not
desired, as soon as a sufficient deposit has been formed to seriously interfere with
the filtration, any remaining liquid is drawn off, the frame is lifted a short distance
from the table so as to release the cloth, and the latter is then set in motion by
suitable means; the portion of the cloth coated with deposit is thus removed from
When this
the surface of the table and replaced by a clean portion of the cloth.
is effected the frame is again lowered, and the process goes on as before. In
passing off the table the wire gauze and the cloth are made to diverge; the former
carries away the bulk of the deposit, which is easily removed. The cloth, and if
necessary, the wire gauze, are led through washing troughs, and are thus
thoroughly cleansed before coming on to the surface of the table again. By this

page_text: means a filtering tank, with a porous bottom, is so arranged, that, when the bottom
is choked with deposit, it can readily be removed and replaced by a fresh one, the
filtration being aided, if necessary, by suction or pressure, or both combined.
Dated this 27th day of Mor 1806
eme
Lus.
I, STANLEY KEMP WELCH, of 1 Challoner Street, West Kensington in the
County of Middlesex, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :--
This invention relates to an apparatus for the rapid removal of solid matter held
in suspension in water or other fluid, especially those substances which settle with
difficulty, and which speedily choke ordinary filters.
The apparatus consists of a table or frame covered except round the edge with
perforated metal wire work or similar material. Beneath this surface is a shallow
chamber communicating with an air pump. At each end of the table is a roller
over which, and resting on the table, is stretched a sheet of cloth or other filtering
material, the sheet passes underneath the table, and through a washing apparatus;
it is suitably guided and is preferably a continuous band, a portion being always in
contact with the surface of the table.
A little above the table is suspended, or held in position, a frame of about the
same dimensions in length and breadth as the table; when lowered on to the table
it makes a tank, of which the bottom is formed by the cloth.
The parts of the frame and of the table which come in contact may be provided
with rubber packing to make a tight joint or the cloth itself may serve to make
the joint.
The mode of operation is as follows:-The frame having been lowered on to
the table, and a tank thus formed, the material to be filtered is run in. The air is
gradually exhausted from the space under the cloth and the pressure of the
atmosphere exerted on the surface of the liquid causes a rapid flow of the filtrate,
leaving the solid matters on the surface of the cloth. This flow will generally
slacken as soon as any considerable deposit forms on the cloth. If it be desirous
to obtain the deposit in as dry state as possible the flow of the liquid to be filtered
is stopped, any liquid remaining on the surface of the deposit is drawn off, and
the vacuum below is continued as long as is found desirable, to consolidate the
deposit.
As soon as the deposit is sufficiently consolidated, or, if a solid deposit is not
desired, as soon as a sufficient deposit has been formed to seriously interfere with
the filtration, any remaining liquid is drawn off, the frame is lifted a short distance
from the table so as to release the cloth, and the latter is then set in motion by
suitable means; the portion of the cloth coated with deposit is thus removed from
the surface of the table and replaced by a clean portion of the cloth. When this
is effected the frame is again lowered, and the process goes on as before. In passing
off the table the cloth carries away the bulk of the deposit which is easily removed.
The cloth is led through a washing trough and is thus thoroughly cleansed before
coming on to the surface of the table again. By this means a filtering tank, with a
porous bottom, is so arranged, that when the bottom is choked with deposit, it can
readily be removed and replaced by a fresh one, the filtration being aided, if
necessary, by suction.

page_text: In order that my invention may be fully understood and readily carried into effect
I will proceed to describe the drawings annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 represents in elevation an apparatus in accordance with my invention.
Figure 2 shows the same in section.
a a are the moveable sides of the tank, they are shown in the drawing lifted above
the bed to enable the cloth to be drawn off.
b is the perforated false bottom on which the cloth rests while filtration is
going on.
c is the true bottom of the filter tank.
d is the filtering cloth, which is here shown as a continuous band.
e is a tank in which the cloth is washed when it comes off the filtering bed.
fis a pipe, leading if suction is used to a pump by which means the filtrate as
well as air is removed from the filter tank.
g are bars lifted periodically by means of cams h.
are bars passing through the bed of the filter tank. They are held down by
lugs on the frame while filtering is proceeding, and are pushed up by springs
below when the frame is lifted, thereby lifting the cloth from the bed b and enabling
it to be readily removed.
k is the driving wheel operating the shaft which works the cams h.
are rollers for supporting and conveying the filtering cloth.
o are weights counterpoising the sides a.
The rollers by which the cloth is drawn off can be worked by hand or by
power, they can be driven automatically in such manner that they revolve whilst
the frame is raised. The deposit is removed from the cloth as it passes over the
rollers at the exit end of the machine. Scrapers are provided when necessary to
remove the deposit from the cloth.
The feed inlet can either be closed by the attendant or cut off automatically.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. In filtering apparatus a tank substantially as described with perforated bottom
and removeable sides and a filter cloth or fabric lying upon the perforated bottom
the whole so arranged that the sides can be lifted and the cloth or fabric then
drawn forward carrying with it out of the tank the solid matter separated by
filtration.
2. Apparatus in accordance with Claim 1 and provided with a washing trough
and a continuous filtering cloth or fabric; the whole so arranged that whilst the
filtration is in progress through one part of the cloth or fabric another part may be
cleansed in the washing trough.
3. Apparatus in accordance with Claim 1 and having a closed chamber beneath
the perforated bottom and filtering cloth or fabric and a pump in connection with
this chamber.
الحملي D1
1
L
2007
S. KEMP WELCH.