Improvements in Filtering Apparatus.
Year: 1891

page_text: Date of Application, 27th Jan., 1891-Accepted, 21st Mar., 1891
COMPLETE SPECIFICATION.
[Communicated from abroad by EDWARD MARTIN KNIGHT, of San Francisco,
California, United States of America, Gentleman.]
Improvements in Filtering Apparatus.
1, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent
Agents, 45, Southampton Buildings, 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:
My invention relates to certain improvements in filters, employing a series
of independent tanks, and means for supporting and securing said tanks in a series
or battery of exterior bracing frames by which the tanks are supported and
connected together, and a system of supply and discharge pipes whereby any one
or more of the series may be cut off and removed, or a new one introduced, and a
system of testing each individual filter independently for leakage without
disturbing any of the others.
My invention relates also to that class of filters in which a fibrous or porous
material is employed to support the filtering medium, and it consists in certain
devices and details of construction which will be hereinafter described.
In the accompanying drawings
Figure 1 is an exterior view showing a series of my filters with connecting
pipes.
Figure 2, is an enlarged view showing the lower part of three of the filters
connecting pipes, cocks and the testing device.
Figure 3 is a view of a part of the bottom and interior of one of the tanks
showing the spreader for checking the flow of the water, and preventing disturbance
of the filter beds.
Figure 4, is a view of one of my filter sides.
Figure 5, is a view of the frame of the same.
Figure 6 is a front view of the outer tank or casing, of one of my filters partly
broken away to show the interior arrangements of the different parts.
Figure 7 is a lateral, vertical cross section through the casing and also one of
the filter sections.
Referring to Figures 1 and 3, inclusive of the drawings A A are series of filter
tanks within each of which I place a filter frame having the sides composed of
fibrous filter beds upon which the filter material hereinafter described is spread in
the form of paste, so that when the exterior tanks are filled with unfiltered
water, it will gradually percolate through the filter beds into the interior of the
filter frames B.
From the interior of these filter frames, pipes C lead downward through the
bottoms of the tanks and are connected with a single main pipe D which extends
beneath the filter tanks. Each of the pipes C is provided with a cock E by
which it may be cut off from the main pipe D, and each of these pipes also has
an extension F with a cock G which ordinarily remains closed when the cocks E
are opened. These extensions are used in testing for leakage, as will be hereinafter
described.
H is the main supply pipe through which water passes, being of sufficient
diameter to carry as much water as will be needed to supply all the filter tanks
at ouca

page_text: Opposite each of these tanks a branch pipe I connects with this main, and is
provided with a cock J which may be opened or closed at pleasure.
These branch pipes connect with the pipes K, opening into the lower part of the
filter tanks, and these pipes K extend downward and have in them cocks L, which
ordinarily remain closed when the supply cocks from the main are opened but
when the supply cocks are closed these cocks L may be opened so that the
unfiltered water can be entirely discharged from the interior of as many of the filter
tanks as may be desired.
Within the filter tanks, and just above the mouths of the inlet pipes, I have
shown a spreader M which consists of a plate fixed a short distance above the
bottom of the tank and directly over the mouth of the inlet pipe, so that all the
water which flows into the tank through this pipe, will impinge upon this spreader,
and will have its direction changed so as to flow out gradually toward each side,
and thus any current which may have a tendency to form from the inlet pipe, will
be broken up and destroyed and the material of which the filter is composed will
not be disturbed or agitated in any way.
It will be manifest by this arrangement of pipes and cocks, that water may be
admitted into any one or more of the whole series of filters, and it may be also cut
off from as many as may be desired, and the unfiltered water contained within the
tanks may be discharged from the tanks. so cut off without in any way interfering
with the operation of the others.
If any leakage is detected whereby the purity of the water is in any way
lessened, I am enabled to test for and locate this leakage immediately by means of
a series of discharge pipes or extensions F, which connect with the interiors of
the filter chambers.
Each tank may be cut off successively from the general discharge pipe into
which the filtered water ordinarily flows and the cock G in the extension F which
projects downwardly from the filter chamber being open water may be drawn
directly from the interior of the filter through this pipe and so on through the
whole series until the one which leaks or shows contamination is detected. It may
then be closed and temporarily removed or repaired.
In order to hold this series of filters together and also enable me to manufacture
the containing tanks of light material, and at the same time in such a manner as
to withstand the pressure of a considerable column of water, I have shown
supporting bars N extending along each side of the filter tanks.
As many of these supporting bars may be used as may be necessary between
the bottom and top of the tank.
I prefer to make them of light angle iron which is sufficiently stiff and they
project a slight distance beyond each end of the filter tanks.
Through the flanges of these angle iron bars holes are made and by means of
bolts the bars upon each side of any one tank are firmly connected together,
while by means of the bolts or rods the side bars of each adjacent tank may
be connected together and the whole thus rigidly and firmly united into a solid
frame work.
Whenever it is necessary to remove any one of the tanks, it is done by loosening
the frame bolts, to release the tank and disconnecting the pipes as previously
described, but the frames remain connected so that there is no danger to the
tanks remaining.
Another form of filter is shown in Figures 4 to 7 inclusive and when using a
filter of the form therein shown I find it desirable to modify the construction
somewhat.
To better describe this form of filter I will say that in practice I have found it
almost impossible to stretch a fibrous covering sufficiently tight to prevent its
sagging away from the exterior screen and this allows the filtering medium which
is composed of charcoal paste to peel and fall off from the fibrous covering. To
overcome these defects I apply a backing of wire cloth or finely perforated sheet

page_text: metal, over which the fibrous material is stretched and secured by a device to be
hereinafter described.
The filtering medium being spread upon the fibrous material forms a filter bed
which will remain intact on account of the rigid support behind the fibrous
material, and the screen itself, is also supported from the interior by certain
arrangement of cross pieces or braces within the filtering frame.
In Figure 5 A represents the filter frame which is made of any suitable material,
but I prefer to make it of sufficiently heavy sheet metal, and B 13 are diagonally
arranged bracing pieces extending from the corners of the exterior frame toward
the centre, perforated so as to allow the free circulation of water through all the
parts of the interior of the frame. These strips B are as wide as the depth of the
filter from side to side, so that when the filtering sides are secured upon the sides of
the frame A¹ they will be supported by the edges of these bracing strips.
The sides of my filter are formed of wire-cloth finely perforated sheet metal, or
in some cases of fine lattice work of any suitable material D¹ having ends pro-
jecting and forming prongs D as shown in Figure 4 and upon this is spread the
fibrous material E which is designed to support the filter bed.
This fibrous material I have preferably shown made of asbestos, as being the
most durable, and its edges are passed over and partially held by the prongs of the
lattice work D as shown in Figure 4 and the filter bed comprises a coating of
finely pulverized charcoal, which is applied by mixing it with water so as to form a
paste, which is afterwards brushed upon and into the fibres of the cloth until a
sufficient thickness has been applied.
The water percolates through this filter bed of charcoal paste and through the
cloth and wire screen into the interior of the chamber formed by these filtering sides
and the supporting frame A'.
In order to secure the fibrous material to the wire or other screen, or support, I
have shown metal plates folded so as to fit over the edges of the screen and the
fibrous material or cloth is made sufficiently larger than the screen so that it folds
over the ends and sides of the screen.
These folded metal strips G¹ are then pressed on over these edges and are after-
wards soldered or otherwise secured together at their meeting angles, and suitably
braced by reinforcing corner pieces, which also prevent leakage at he angles, thus
securing the fibrous material so that it forms a smooth and unyielding surface upon
the exterior of which the filter bed is applied, as previously described.
The folded plates which form the surrounding edges of the filtering sides are
then soldered or otherwise hermetically secured upon the edges of the frame A',
and the diagonal bracing pieces B₁ support the central portions of the screen
surface upon which the cloth is stretched, thus preventing the screen from being
bent inward, by the pressure of water upon it, and the screen, in turn, prevents any
inward sagging of this fibrous cloth. This is important because if any sagging of
this kind should take place, the paste or filter bed which is applied to the cloth will
fall off, and thus impair the efficiency of the filter.
By this construction I am enabled to entirely dispense with any outer covering
or support for the filter medium and it enables me at all times to easily cleanse the
filtering surface or replace the filter bed upon it.
Another important feature in my invention is the manner of securing the edges
of the cloth or fibrous material so as to form a water tight joint around these edges,
and prevent any leakage of unfiltered water through this joint.
This filter frame is contained within the outer casing of chamber H, and the
filtering frame has a tubular stay 11 passing through its top, bottom and also
through the interior bracing strips B' to which it is secured. It is also
secured to the top and bottom of the filtering frame by flanges or collars, so
that when the filter is lifted by the tube l' it is perfectly rigid and the bottom
cannot sag.
The extension of the tube I¹ at the bottom has a suitably formed ground rubber

page_text: or other water tight joint I which connects with the pipe delivering into the
reservoir chamber beneath, which is adapted to contain the filtered water.
་
This pipe is perforated inside of the case A so that the filtered water which
has flowed into this case through the filtering sides, may pass through these perfora-
tions, and thence down through the pipe into the reservoir or discharge pipe as the
case may be.
In order to prevent the filter frame from rising up within the exterior case, I
have shown two parallel strips J fixed across the upper part of the exterior case,
and between these the upper end of the tubular stay passes.
A nut or screw K' is fixed to turn the threaded portion at the upper end of the
tube I, and after the filter frame is in place and the joint I properly connected
at the bottom, this nut is turned up against the cross strips or pieces J and thus
hold the frame in place, preventing it. from rising.
The filter frame is easily removed by loosening the nut K' and disengaging the
pipe from the joint at the bottom. The upper end of this tube serves to admit
air into the interior of the filter frame by means of holes L'inade in the tube or
adjusting collar just beneath the upper side of the filter frame, and as the water
passes down into the reservoir beneath through the holes which are made in the
lower part or near the bottom of the filter frame, it will be manifest that the air
will be caused to circulate through this tube, and will sufficiently acrate the water
which has been filtered.
1 prefer to construct the unfiltered water reservoir or exterior casing into which
the filter frame is introduced of iron, and the reservoir for containing the filtered
water I prefer to make of tinned copper, but as this has not a great amount of
rigidity to resist internal pressure, I have shown a truss or bracing of steel or iron
plates M covered with tinned copper, made of sufficient thickness to keep the top
and sides of the reservoir in their proper position, and to resist any pressure which
may be brought upon the comparatively soft metal of the reservoir and which it
is not stiff enough to resist.
By thus separating the casing which contains the unfiltered water from
the reservoir, and uniting them as shown, any leakage in the former will pass
down outside of the filtered water reservoir and not contaminate its contents.
am also enabled to make the unfiltered water tank of galvanized iron which is
inexpensive and the filtered reservoir only need be made of the more expensive
tinned copper.
By means of the truss plates or supports for the ground joint 1 prevent the
reservoir from sagging or changing shape, and thus ensure a perfect joint where
the pipe I delivers water from the filter to the reservoir, and prevent leakage
without resort to screw or other connections which are more difficult to uncouple.
Water may be admitted into the case which contains the filter frame either from
the top or the bottom. In either case it is desirable to prevent the water from
flowing in, in such a manner as to create currents within the chamber and thus
disturb the filter bed and wash it off.
When the water is admitted from the top it may be done by means of the
cock N having the ordinary float or ball O' connected with the lever arm so as to
cut off the supply by closing the cock when a sufficient amount of water has been
admitted into the exterior chamber.
From the mouth of the cock I have shown directing plates P which are so
arranged as to receive the water as it flows from the cock, and to deliver it
against the sides of the chamber, so that it will flow down gently and easily,
and without any splash which would disturb the water and make it liable to wash
off the filter bed.
In order to render the sides of the sheet metal vessel which contains the filtering
frame, sufficiently stiff to support the ball cock N, and to allow the movement of
the cock by the rise and fall of the float, without twisting or bending the side of
the chamber, have shown a reinforcing plate R₁ soldered or otherwise secured to

page_text: the side of the vessel at this point as will enable it to withstand the twisting
pressure caused by the rising and falling of the ball, and as the side is thus
prevented from yielding, it will insure the cock acting perfectly so as to cut off the
supply of water and prevent the constant leakage which might otherwise occur, or
the necessity for making the vessel of very much heavier material.
For the purpose of lessening the cost of manufacture to facilitate the cleansing
of the filter and renewal of the filter bed to increase the capacity and to detect
and locate leakage, I have shown in Figures 6 and 7 an exterior case adapted to
contain two or more filtering frames, each constructed as previously described and
adapted to fit within the exterior case side by side where they are held in place by
the tubular stays I', and each of the pipes through which the filtered water
escapes at the bottom is fitted into the ground joint, which joint is supported by
the rigid iron or metal bar fitted into the sides and top of the reservoir tank and
having a direct bearing thereon, and this gives great stability and rigidity to these
joints insures their remaining tight, and prevents leakage of unfiltered water from
the case and holding the same in the unfiltered water reservoir.
In order to inspect the interior of the reservoir at any time when the water has
been drawn off, I have shown a large screw cap or cover S' fitted into one end of
the reservoir, preferably by screwing into the ring or flange which is fixed into
the end of the reservoir. When this is removed the interior of the reservoir is
easily reached and inspected and if that has been discovered that the water from
the reservoir is in any way contaminated, I am enabled by removing this cap or
cover to detect any leakage from the tanks above and by collecting a portion of
the water delivered from each one in a glass I can at once determine which of the.
filters in the case above is delivering impure water. This may then be removed
after discharging the water from the tank, and the error rectified without..
disturbing any of the other filtering frames.
.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, 1 declare that what I claim is :-
First. A filter consisting of asbestos cloth or other fibrous material, an exterior
coating of filtering medium spread upon the cloth, and an interior rigid supporting
screen over which the fibrous material is stretched, and by which it is prevented
from sagging, said inner supporting screen having projecting prongs over which
the edges of the fibrous material are passed whereby said material is secured,
substantially as herein described.
Second. In a filter the foraminous plate or screen forming an interior rigid
support for the filter bed, a filter bed composed of asbestos cloth or other fibrous
material stretched over the exterior of the screen and having the edges projecting
and folded over the edges of the screen and folded metal plates adapted to clasp
the edges of the cloth and the screen, said plates being soldered or secured so as to
retain the screen and cloth and form a tight joint between the edges thereof,
substantially as described.
Third. A filter consisting of asbestos cloth or other fibrous material and an
exterior coating of filtering medium in the form of paste spread upon the cloth, a
rigid interior screen forming a back or support for the filter bed over the edges of
which the cloth is folded clamping strips fitted over the folded edges of the cloth
and soldered or secured so as to retain it stretched over the screen, and supple-
mental corner pieces or plates fitted upon the angles of the filter frame, sub-
stantially as herein described.
Fourth. In a filter, the exterior frame having the filtering sides the supporting
screens and the diagonal plates upon which the screens rest in combination with
the tubular stay extending vertically through the filter frame and diagonal plates,
and having the adjusting. collars whereby the stay is connected with both top. and.

page_text: bottom of the frame and the central plates so that the filter frame may be lifted
without twisting it out of shape, substantially as herein described.
Fifth. In a filter, the filter frame having the diagonal and perforated bracing
plates, sides formed of screens supported upon the edges of the interior plates and
hermetically secured to the edges of the frame, a fibrous filter bed stretched over
said screen having its edges secured thereto and a coating of filtering material
applied to the exterior of the fibrous cloth in the form of a paste in combination
with an exterior casing for containing unfiltered water within which the filter
frame is submerged, and a tubular stay extending through the filter frame from
top to bottom having perforations in the lower part within the filter frame through
which water may flow from the interior of the filter frame into a tube, a ground or
rubber joint exterior to the lower part of the filter frame through which the
filtered water passes out and a transverse brace fixed across the upper part of the
casing and having a locking device which engages the upper end of the tubular
stay whereby the filter frame is prevented from rising and the joint at the lower
end is kept tight, substantially as herein described.
Sixth: A filter frame consisting of an exterior casing, one or more filter frames
having the filtering sides, interior screen supports for said, sides, and the plates
upon which the screens are supported, a tubular stay extending through each of
the filters having a ground or rubber joint at the lower end by which connection is
made with the reservoir or receiver of the filtered water openings into said tube
near the bottom and interior of the filter frame, through which water escapes
therefrom, into the tube, and openings within the upper part within the filter
frame through which air may be admitted from the upper end of the tube to aerate
the filtered water, a transverse brace fixed in the upper part of the exterior casing
and adjusting nuts or collars fitted upon the tubular stay so as to engage the
brace and hold the filter frames in place within the casing, substantially as herein
described.
I
Seventh. A filter consisting of an exterior casing, one or more filter frames
having the filtering, sides through which the water passes from the exterior casing
to the interior of the filter frames, and a pipe or passage through which the water
escapes from the exterior of said filter frames in combination with a reservoir into
which said pipes deliver the filtered water a ground or rubber joint between the
unfiltered and filtered water reservoirs, and a strengthening stay or support within
the filtered water. reservoir, upon which the ground joint is fixed and supported
substantially as herein described.
Eighth. In a filter a series of tanks set side by side and having enclosing bands
or bars and connecting bolts whereby the sides of each tank are supported and a
series of tanks connected together substantially as herein described.
Ninth. In a filter a series of tanks set side by side and united together a
common supply pipe having branch pipes with cocks delivering water into the
bottom of each tank independently other pipes connecting with the same inlet
passages and provided with cocks and connecting with a common discharge pipe
through which the unfiltered water within any of the tanks may be discharged
independent of the others, substantially as herein described.
Tenth. A filter consisting of a series of tanks supported and united as shown a
common supply pipe having a branch pipe and cock opening into the bottom of
each of the filter tanks discharge pipes connecting with the same openings and
having cocks and a common discharge pipe with which they are connected pipes
connected with the filtering frames within the tanks and a common receiving pipe
for the filtered water with which said pipes are connected and cocks whereby any
one or more of the filter chambers may be cut off from the receiving pipes substan-
tially as herein described.
Eleventh. A filter consisting of a series of tanks having interior filter chambers
through the bottom or sides of the tanks and connecting with a common receiving
and discharge pipe for filtered water cocks whereby said pipes may be cut off from

page_text: the common discharge pipe and other pipes connecting with said discharge pipes
and provided with cocks through which water may be drawn directly from any one
or more of the filter chambers independently of the others whereby leakages may
be detected, substantially as herein described.
Dated this 27th day of January 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.