Improved Apparatus for Filtering Sewage and other Liquids.
Year: 1890

page_text: Date of Application, 26th Mar., 1890
Complete Specification Left, 1st Aug., 1890-Accepted, 6th Sept., 1890
PROVISIONAL SPECIFICATION.
Improved Apparatus for Filtering Sewage and other Liquids.
I WILLIAM BIRCH of Milton Street Iron Works Lower Broughton Manchester in
the County of Lancaster Engineer do hereby declare the nature of this invention
to be as follows:-
The object of this invention is to construct a filter in such a way that the filtering
surface shall always be changing and shall be kept continuously clean.
I
For this purpose propose to use an endless felt or filtering cloth or fabric which is
kept in continuous or intermittent forward motion by any convenient means, and
passing loosely round drawing or carrier rollers dips into a trough or vessel containing
the liquid to be filtered.
The hanging portion of the felt or cloth dips below the liquid and lies upon the
curved face of a hollow perforated bed or grid which forms a false bottom to the
trough or vessel, so that the liquid passes through the felt or cloth and through the per-
forations or openings in the curved grid or false bottom into the space beneath whence
it flows away or is drawn off in any convenient uianner.
I prefer to fit the curved perforated bed or grid with rollers almost flush with the
surface so as to facilitate the passing of the endless felt or cloth over the same, and to
employ small metal rollers above the felt to keep it down against the bed or grid, the
ends of such last named rollers working in vertical slides so that they can revolve with
the felt or cloth without progressing and can readily be lifted out when required.
As the endless cloth passes on either continuously or intermittently it carries with it
out of the trough or vessel the solid refuse matter which the water has precipitated or
deposited thereon together with a certain amount of water which the felt has absorbed
and before the felt passes over the drawing or carrier rollers to the filtering trough or
vessel it is necessary to cleanse the same from this solid precipitate or refuse, and the
method of doing this forms an important feature of my invention.
The felt or cloth after leaving the filtering trough or vessel passes over or against
concave, convex or flat surface which is preferably fixed, but a slowly revolving
roller of large diameter may be employed instead of a fixed convex surface.
As the felt passes over this surface a roller of small diameter is caused at intervals
to press or squeeze the same with a rapid backward sweeping motion accompanied by
more or less pressure so that the water in the felt is squeezed outwards and being at
the same time rapidly urged forwards carries all the deposit or refuse matter with it,
leaving the felt or cloth clean and comparatively dry.
The rapid backward sweeping motion of the small roller may be effected in a variety
of ways without departing from the principal features of this method of cleansing
but for the sake of illustration I will here describe what I have found to be a convenient
and effective arrangement of mechanism for the purpose.
I fix a concave surface in a perpendicular position just above the exit side of the
filtering trough or vessel and I mount the small squeezing roller on two radial arms
the fulcrum of which corresponds with the centre of the curve of the concave surface.
These arms are actuated by two snail shaped cams which have a graduated rise and
a sudden fall so that the roller is alternately carried upwards at about the same speed
as the filtering felt or cloth or rather faster and is then suddenly released and allowed
to sweep rapidly backwards over the surface of the felt driving the water and deposit
or refuse with it which falls into a trough or gutter arranged for that purpose from
whence it is drawn off or allowed to flow away.
In order to prevent the cleansing roller from pressing against the surface of the

page_text: felt or cloth as it rises up and to cause it to press strongly against the said surface as
it sweeps down again the radial arms above mentioned are provided with elbow joints
and springs which give way as the levers are raised up but stiffen and press the roller
against the felt as the roller sweeps downwards, whereby the water is squeezed suddenly
out of the felt and washes or swills the deposit away with it, and thus the filtering
felt or cloth is effectually cleansed before passing again into the filtering trough or
vessel.
In cases where the sewage or water contains straws or other matter which could not
be swept away by the above arrangement I also propose to employ a beater or beaters
at the top of the apparatus to act upon the felt or cloth as it passes over the upper
part so as to loosen such straws or other similar matters and shake them off the surface
onto a board or into a receptacle provided for that purpose.
Dated this 25th day of March 1890.
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improved Apparatus for Filtering Sewage and other Liquids.
WILLIAM BIRCH of Milton Street Iron Works Lower Broughton Manchester in
the County of Lancaster Engineer 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
:-
The object of this invention is to construct a filter in such a way that the filtering
surface shall always be changing and shall be kept continuously clean.
The nature of my said invention and the manner in which the same is to be performed
or carried into practical effect will be readily understood on reference to the drawing
hereunto annexed and the following explanation thereof.
The drawing represents a vertical section illustrating the construction and application
of the apparatus which constitutes my invention.
I propose to use an endless felt or filtering cloth or fabric a which is kept in
continuous or intermittent forward motion (in the direction shown by the arrows) by
any convenient means and passes loosely round drawing and carrier rollers, and dips
into a trough or vessel e into which the liquid to be filtered is admitted by a pipe d
preferably fitted with a spreader e.
C
The lower hanging portion of the felt or cloth dips below the liquid and lies upon
the curved face of a perforated bed or grid which forms the bottom of the trough
or vessel c so that the fiquid passes through the felt or cloth a and through the
perforations or openings in the curved grid or bottom into the space beneath.
This space may be either open as shown on the drawing, and a well, tank, or other
open receptacle may be placed beneath, or it may be confined or closed and the filtered
water may flow away or be drawn off therefrom in any convenient manner.
I prefer to fit the curved perforated bed or grid with rollers g flush with the
surface (or the rollers g may be so close together that they themselves form the bed or
grid) so as to facilitate the passing of the endless felt or cloth a over the same, and to
employ small metal rollers above the felt to keep it down against the bed or grid f
the ends of such rollers working against slides or inclines i so that they can revolve
with the felt or cloth without progressing and can readily be lifted out when required.
As the endless felt or cloth a passes on either continuously or intermittently it carries
with it out of the trough or vessel c the solid refuse matter which the sewage or other
water has precipitated or deposited thereon together with a certain amount of water
which the felt has absorbed, and before the felt passes over the top drawing or carrier
rollers to enter again into the filtering trough or vessel c it is necessary to cleanse the
}

page_text: same from this solid precipitate or refuse, and the method of doing this forms an
important feature of my invention.
The felt or cloth a after leaving the filtering trough or vessel passes over or against
a fixed concave surface k, but I would here remark that although preferable, it is not
necessary that this surface should be concave nor that it should be fixed, as a convex
or flat surface may be employed or a slowly revolving cylinder of large diameter may
be substituted, but in either of these cases the movement of the cleansing apparatus
hereinafter described will have to be employed accordingly...
As the endless felt or cloth passes over this surface a roller of small diameter is
caused at intervals to press or squeeze the same with a rapid backward sweeping
motion accompanied by more or less pressure so that the water in the felt is squeezed
outwards and being at the same time rapidly urged backwards carries all the deposit
or refuse matter with it leaving the felt or cloth clean.
The rapid backward sweeping motion of the small roller / may be effected in a variety
of ways without departing from the principal features of this method of cleansing,
but for the sake of illustration I will here describe what I have found to be a convenient
and effective arrangement of mechanism for that purpose.
I fix the concave surface k in a perpendicular position just above the drawing or
carrier roller at the exit side of the filtering trough or vessel c and I mount the
small squeezing roller on two levers m (one at each end) carried by radial arms in
loose on a shaft which corresponds with the centre of the curve of the concave
surface k.
On the same shaft o are also fixed two other arms p the ends of which act against
projections 7 on the ends of the levers m furthest from the roller 1. A spring ris
also provided on the arm or lever n acting against the projection m' on the lever m,
so that the whole arrangement forms a sort of elbow joint; m² is a spring or buffer to
receive the weight of the levers m and n and break the shock of the fall.
l
On the shaft o are also fixed two short slotted levers s to each of which is connected
a rod t having a projection t' at the top resting upon a snail shaped cam u which has
a gradual rise and a sudden fall, and these two cams are mounted on the axis of one
of the drawing rollers (12) so that as this roller revolves the cams revolve with it and
the cleansing roller is alternately carried upwards at a little greater speed than the
filtering cloth or felt a and is then suddenly released and allowed to sweep rapidly
backwards over the surface of the felt into the position shown in dotted lines, driving
before it the water and deposit or refuse which falls into the trough or gutter v arranged
for that purpose from whence it is drawn off or allowed to flow away.
In order to prevent the cleansing roller from pressing against the surface of the
felt or cloth a as it. rises up, it is held in the position drawn in full lines by the
projection m' acting against the spring r above named, causing the elbow joint to give
way as the levers or arms p are raised up, but to stiffen and press the roller against
the felt as it recedes downwards, whereby the water is squeezed suddenly out of the
felt and washes or swills away the deposit with it, and thus the filtering cloth a is
effectually cleansed before passing again into the filtering trough or vessel c.
In some cases where the sewage or water contains straws or other matter which
could not be swept away by the above arrangement I may employ a beater or beaters
at the top of the apparatus to act upon the felt or cloth as it passes over the upper part
so as to loosen such straws or other similar matters and shake them off the surface onto
a board or into a receptacle provided for that purpose.
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 :-
The construction of endless travelling and self cleansing apparatus for filtering
sewage and other liquids substantially as herein before described and illustrated by the
drawings annexed, and especially I claim the arrangement for cleansing the endless
felt or filtering cloth consisting essentially of a roller of small diameter which is

page_text: caused at intervals to press or squeeze the same with a rapid backward sweeping motion
accompanied by more or less pressure in combination with a suitable resisting surface
substantially as described and illustrated.
Dated this 31st day of July 1890
GEORGE DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicant.