IMPROVEMENTS IN FILTERS
Year: 1877

page_text: LETTERS PATENT to Francis Thomas Bond, of Gloucester, in the County of
Gloucester, Doctor of Medicine, for the Invention of "IMPROVEMENTS IN
FILTERS"
Sealed the 31st May 1878, and dated the 7th December 1877.
PROVISIONAL SPECIFICATION left by the said Francis Thomas Bond at the
Office of the Commissioners of Patents on the 7th December 1877.
FRANCIS THOMAS BOND, of Gloucester, in the County of Gloucester, Doctor of
Medicine. "IMPROVEMENTS IN FILTERS."
The improvements to which this Invention refers are of several kinds.
The first of these is an improved form of a filter which is described in the Specifi-
cation accompanying Letters Patent for "Improvements in Filtering and Purifying
Water and other Liquids, aud in the Apparatus Employed therein," which were
granted to me on the 30th of September 1876, No. 2747, and is also Figured in No. 2
of the Drawings accompanying the said Specification.
The improvements which I have effected in this form of filter consist in making
the cover removable, and in connecting it when applied to the body of the filter by
an india-rubber band around the line of junction, so as to make the connection
between the two water-tight.
Also in placing in the upper part or air chamber of the filter a light cup, which
closely fits the said chamber, and which can be used for drinking purposes.
The filter when so constructed can be used in three ways, first, as a floating filter
in the way described in the Specification referred to above; second, by taking out
the cup, filling the whole of the vessel with filtering material, and replacing the
cover, when the filter may be immersed in the liquid to be filtered, being started by
suction, and kept in action in the same way as if it were a floating filter; thirdly,
as a downward filter, the cover being taken off, and the liquid to be filtered being
poured downwards through the filtering material, from which it escapes by the
aperture in the bottom. The action of the filter in this case is much promoted by

page_text: attaching to the aperture at the base a tap, or a piece of elastic tubing, on which is
placed a screw clip, such as that which I have recommended for use on the lengthened
syphon tube of the filter when used by flotation. By this means the rate of flow
of the liquid downwards through the filter bed can be easily regulated.
The second improvement to which this Invention refers consists of a more or less
cylindrical vessel, open at both ends. The upper end of this vessel I close with a
cork or other convenient embouchure, which must be air-tight, in the centre of which
I insert a small glass or metal tube. I then fill the cylinder with any appropriate
filtering materials, though I prefer for the purpose to place a piece of sponge in the
upper part of the cylinder, then to fill up the greater part of the rest of it with
granulated animal charcoal, and lastly to pack rather tightly another piece of sponge
into the base of the cylinder, partly for the purpose of preventing the charcoal from
falling out, and partly to act as a preliminary strainer. I then connect with the
tube at the top of the vessel a piece of elastic tubing sufficiently long to act as a
syphon, to which I attach a sciew clip, small tap, or other convenient means of
regulating the flow of the water. I then adapt any simple form of stand to the
bottom of the cylinder, so as to increase its stability, though this is not absolutely
essential to its action. The vessel so arranged is to be placed in a jug or other
convenient vessel containing the water to be filtered, and suction is to be made at the
free end of the elastic tubing until water flows out of it. The water as it passes:
upwards will be effectually filtered, and when the contents of the containing vessel
aie exhausted, air will find its way up into the cylinder, and will put a stop to the
syphon action, which will be followed by the water in the cylinder gravitating
downwards, and thus cleansing the filter to a certain extent by its own automatic
action. This form of filter can be very easily cleansed, as the filtering materials are
very accessible
In order to effect the third of the improvements to which this Invention refers,
I take a more or less cylindrical vessel, similar in form and arrangement to the one
just described, except that I close the upper end of the cylinder with a cork or any
other easily removable but air-tight embouchure, and that I also fix a piece of glass
or metal tube in the centre of the cylinder and its contents, in such a way that the
upper end may be just below, but not touching the lower surface of the embouchure,
and the lower end may project for a short distance below the lower end of the
cylinder. I then place the cylinder so arranged in the interior of a larger and more
or less cylindrical vessel of the same height, preferably of a vase shape, in the bottom
of which I make an aperture, into which I fit the said tube by means of a cork, piece
of india-rubber tubing, or in any other water-tight way, so that it shall project
through the bottom of the outer vessel. I then attach to the end of the tube a tap,
piece of india-rubber tubing with screw clip, or any other similar means of regulating
the flow of the water. The two vessels thus arranged may be placed on any con- 4
venient form of stand, though I prefer for the purpose one like that which is used by
chemists for the purpose of supporting retorts, & commonly known as a retort
stand, because the height of the filter can thus be easily adjusted. If the embouchure
is then taken out of the upper end of the inner vessel, and that at the lower end
of the tube is at the same time closed, and water is poured into the outer one, the
water will make its way under the edge of the inner vessel, and will soon stand in
both vessels at the same height. When both vessels are thus filled, the embouchure
is to be fixed on the top of the inner one, and the lower one is to be opened and
adjusted, so that the water may not run through too rapidly for effectual filtration.
When the water in the outer vessel is exhausted the syphon action in the inner
vessel will be interrupted, and the water inside it will gravitate downwards, and
will thus automatically promote the cleansing of the filter bed in the same way as
in the previous form of filter.
The fourth improvement to which this Invention refers consists in a movable
plate for covering the filter bed in cylindrical filters, such as those Figured in the
fourth and eighth of the Drawings appended to the Specification of my Patent
referred to above. For this purpose I tako a disc of slate, earthenware, or metal, .

page_text: and I attach to its margin a rim or flange of india-rubber in the following way :-
I make a ring of small holes in the disc near its margin, and I attach the flange to
the disc by means of wire, pins, or studs, passed through the holes, and over or into
a ring of metal placed in the flange, so as to hold it firmly in its position. The
junction of the flange and disc I make water-tight by covering it with a cement
composed of pitch and gutta percha melted together in equal parts. I then make an
aperture in any part of the disc, in which aperture I fix a piece of tube with fine
holes in its sides, and terminating in a fine hole at its apex. Around this tube I
bind a piece of sponge or linen, leaving the hole at the top free. The plate so
constructed should then have a handle fixed on the surface on which the perforated
tube projects, and if it be so adapted in size to the cylindrical vessel employed as a
filter that it shall just fit down into it when pressed downward, it will form a cover
for the filter bed, through which the water cannot pass except by means of the
perforated tube and protecting covering, the aperture in the top of this tube serving
as an exit for any air that may be imprisoned beneath the plate as it is pressed
down.
SPECIFICATION in pursuance of the conditions of the Letters Patent and of
an Order of the Lord Chancellor filed by the said Francis Thomas Bond in
the Great Seal Patent Office on the 17th June 1878.
FRANCIS THOMAS BOND, of Gloucester, in the County of Gloucester, Doctor of
Medicine. "IMPROVEMENTS IN FILTERS.”
The filters to which this Invention refers are of several kinds.
The first of these is an improved form of a filter which is described in the
Specification accompanying Letters Patent for "Improvements in Filtering and
Purifying Water and other Liquids, and in the Apparatus Employed therein,"
which were granted to me on the 30th of September 1876, and is also Figured in
No. 2 of the Drawings accompanying the said Specification. The improvements
which I have effected in this form of filter consist in making the cover removable,
and in connecting it when applied to the body of the filter by an india-rubber band
around the line of junction so as to make the connection between the two air and
water-tight.
Also in placing in the upper part or air chamber of the filter a light cup
which closely fits the said chamber, and which can be used for drinking
purposes.
The filter when so constructed can be used in three ways; first, as a floating
filter in the way described in the Specification referred to before; secondly, by
taking out the cup, filling the whole of the vessel with filtering material, and
replacing the cover, when the filter may be immersed in the liquid to be filtered,
being started by suction and kept in action in the same way as if it were a floating
-

page_text: filter; thirdly, as a downward filter, the cover being taken off and the liquid to be
filtered being poured downwards through the filtering material, from which it
escapes by an aperture in the bottom of the vessel. The action of the filter in this
case is much promoted by attaching to a tube which is fixed in the aperture at the
base a tap or a piece of elastic tubing, on which is placed a screw clip, such as that
which I have recoinmended for use on the lengthened syphon tube of the filter
when used by flotation. By this means the rate of flow of the liquid downwards
through the filtering bed can be easily regulated.
The second improvement to which this Invention refers consists of a more or less
cylindrical vessel open at both ends. The upper end of this vessel I close with
a cork or other convenient embouchure, which must fit air-tight, in the centre of
which I insert a small glass or metal tube; I then fill the vessel with any
appropriate filtering materials, though I prefer for the purpose to place a piece of
sponge in the upper part of the vessel, then to fill up the greater part of the rest of
it with granulated animal charcoal, and lastly, to pack rather tightly another picce
of sponge into the base, partly for the purpose of preventing the charcoal from
falling out, and partly to act as a preliminary stramer. I then connect with the
tube at the top of the vessel a piece of elastic tubing sufficiently long to act as a
syphon, to which I attach a screw clip, small tap, or other convenient means of
regulating the flow of water. I then adapt my simple form of stand to the bottom
of the cylinder so as to increase its stability, though this is not essential to its
action The vessel so arranged is to be placed in a jug or other convenient vessel
containing the water to be filtored, and suction is to be made at the free end of the
elastic tubing until water flows out of it The water as it passes upward will be
effectually filtered, and when the contents of the containing vessel are exhausted
air will find its way up into the filtering vessel, and will put a stop to the syphon
action, which will be followed by the water in the filtering bed gravitating down-
wards, and thus cleansing the filtering bed to a certain extent by its own automatic
action This filter can be very easily cleansed as the filtering materials are very
accessible
In order to effect the third of the improvements to which this Invention refers,
I take a more or less cylindrical vessel, similar in shape and arrangement to the one
just described, except that I close the upper end of the cylinder with a cork or
other easily removable, but air-tight embouchure, and that I also fix a piece of glass
or metal tube in the centre of the cylinder and its contents in such a way that the
upper end may be just below, but not touching the lower surface of the embouchure,
and the lower end may project for a short distance below the lower end of the
cylinder. I then place the cylinder so arranged in the interior of a larger and more
or less cylindrical vessel of the saine height, and preferably of a vase shape, in the
bottom of which I make an aperture into which I tit the said tube by means of a
cork, piece of india-rubber tubing, or in nuy other water-tight way so that it shall
project through the bottom of the outer vessel. I then attach to the end of the
tube a tap, piece of india-rubber tubing with screw clip, or any other similar means
of regulating the flow of water. The two vessels thus arranged may be placed on
any convenient form of stand, though I prefer for the purpose one like that used by
chemists for the purpose of supporting retorts, and which is commonly known as
a retort stand, because the height of the filter can thus be more readily adjusted.
If the embouchure is then taken out of the upper end of the inner vessel, and the
regulator of the lower end of the tubo is at the same time closed, and water is
poured into the outer vessel until the latter is full, the water will make its way
under the edge of the inner vessel, and will soon stand in both vessels at the same
height. When both vessels are thus nearly full, the embouchure is to be fixed on
the top of the inner one, and the tap or other regulating arrangement at the lower
end of the tube is to be opened and adjusted so that the water may not run
through too quickly for effective filtration. When the water in the outer vessel is
exhausted the syphon action in the inner vessel will be arrested, and when air finds
its way into this vessel the water left in it will gravitate downwards, and will thus

page_text: wwwomatically cleanse the nitering bed in the same way as described in the previous
form of filter.
The fourth improvement to which this Invention refers consists in a moveable
plate for covering the filtering bed in cylindrical filters, such as those Figured in
the 4th and 8th of the Drawings appended to the Specification of my Patent
referred to above. For this purpose I take a disc of slate, earthenware, or metal,
and I attach to its margin a rim or flange of india-rubber in the following way:-
I make a ring of small holes in the disc near its margin, and 1 attach the flange to
the disc by means of wire, pins, or studs passed through these holes, and over or
into a ring of metal placed on the flange so as to hold it firmly in its position. The
junction of the flange and disc I make water-tight by covering it with a cement
made of pitch and gutta-percha melted together in equal parts, or with any similar
material. I then make an aperture in any part of the disc, in which aperture I fix
a tube with holes pierced in it just above the disc and terminating in a fine hole at
its apex. Around the part of this tube where the holes are I bind a piece of sponge
or linen for the purpose of acting as a preliminary strainer of the water before it
passes into the body of the filter. The plate so constructed should have a handle
fixed in the centre of the surface on which the perforated tube projects, and if it bo
so adapted in size to any cylindrical vessel employed as a filter that it shall just fit
into it with a little pressure, it will form a cover for the filtering bed through
which the water cannot pass except by means of the perforated tube and its pro-
tecting covering. The aperture on the top of the tube serves as an exit for any air
that may be imprisoned beneath the plate as it is pressed down, and also as an inlet
for air when the water in the space above the plate is exhausted, so that the
filtering bed is thus freely aerated each time that the filter is emptied of water.
Having thus described generally the improvements in which my Invention
consists, I will now proceed to illustrate the same by means of the Drawings here-
unto appended.
In the said Drawings Fig. 1 is a vertical section through the middle of my
improved form of floating filter. In this Drawing A is the body of the filter, which
is here represented as cylindrical in form, though it may be made of a conical or
any other convenient shape; B is a loose cover, to the margin of which is attached
the india-rubber flange C, which fits tightly on the cylinder when the cover is
applied to it In the centre of this cover is fixed the tube D, which is of sufficient
length to allow of the air contained in the chamber L, which it thus forms in the
upper part of the filter, giving the vessel flotation when the lower part is packed
with filtering material G. On the top of this latter rests a cup, which exactly fits
the interior of the filter, and in the bottom of which is an aperture to allow of the
passage of water upwards through it from the filtering bed. Small pieces of
sponge
S, S, are placed under the aperture in the bottom of the cup, and over that in the
bottom of the filter respectively, in order to prevent the finer particles of the
filtering material finding their way through.
Instead of the cup H a simple plate perforated with one or more holes, and with
an india-rubber flange to keep it firm in its position may be used, or both cup
and plate may be dispensed with; but in such case particles of the filtering material
are very apt to find their way into the exit tube. To the upper end of the tube D,
which projects slightly through the cover, is attached a flexible tube E, sufficiently
long to form a syphon, on which is placed the screw clip F, for the purpose of regu-
lating the rate of flow through it.
In Fig. 2 A is represented the way in which the appliance just described is used
as a floating filter, and the same Figure also shews the two other ways in which it
may be further employed for purposes of filtration, viz., B, with its cavity altogether
filled with filtering material, when it may be used as an immersion filter; and C
for use by downward percolation, the cover being taken off and the liquid to be
altered being poured into the upper part of the vessel. When thus used the rate
of filtration may be controlled by attaching a small piece of elastic tubing to the

page_text: tube at the bottom of the niter, and placing on it the screw clip before
referred to.
In Fig. 3 is shewn the second of my improved appliances for filtration, in which
A is a cylindrical vessel tapering towards the top so as to form a neck, and with a
constricted base resting on a foot broad enough to give it stability. The aperture
in the neck is closed by a cap B, with an india-rubber flange C adapted to it, which
fits tightly on the surface of the neck, and so makes the junction air-tight. But
instead of the cap any other convenient tight-fitting embouchure may be used, as
stated before. In the centre of the cap is fitted a pipe, to which is attached a piece
of india-rubber tubing E, with a regulating screw or tap F placed on it. The
aperture in the base of the vessel is closed by a piece of sponge S, tightly com-
pressed into it, and the body of the vessel is filled with animal charcoal, or other
appropriate filtering material G, on the top of which, just beneath the embouchure,
it is desirable to place another piece of compressed sponge S in order to prevent the
finer particles of the filtering material from finding their way into the pipe at the
top. The vessel A may be made either of glass, earthenware, or metal.
•
Fig 4 represents the third of my improved appliances for filtration, in which A
is a cylindrical vessel, open both at top and bottom, and resembling somewhat in
shape that which has been just described. In this vessel is placed a metal tube H,
open at both ends, the upper end of which projects through and is fixed in the
centre of a circular plate K, having perforations in it, and which is adapted to take
a bearing against the shoulder of the vessel A so as to prevent the tube being forced
upwards into the neck beyond this point. In the lower end of this tube a screw
thread is turned, into which a tapering screw is fitted, by means of which the
aperture can be partially or entirely closed, & the rate of flow of water through the i
aperture can be regulated.
The form of this screw regulator is more fully shown in Fig. 5. The body of the
vessel A below the plate K is filled with animal charcoal or other appropriate filtering
material G, and a piece of sponge S is compressed firmly into the aperture at the
base, as in the filter shewn in Fig. 3. The vessel so constructed is placed in another
vessel D, in the bottom of which is fixed a tube just large enough to allow the
tube H passing through it, the junction between the two being made water-tight by
means of a piece of india-rubber tubing slipped over it. The aperture in the neck
of the vessel A. is closed by a cap B, with india-rubber flange, or by a cork or other
air-tight fitting embouchure. The filter thus constructed may be supported on a 3
stand, as before described, or on a jug or other convenient vessel, which will act as
a receiver of the filtered water.
In Fig. 6 is represented a sectional and also a plan view of the movable plate, in
which the fourth of my improvements consists, in which A is the disc, B the handle
of the same, C the india-rubber flange attached to the margin of the disc by a com- 4
bination of wire or of pins and cement, as before described, the said wire or pins
being prevented from cutting through the india-rubber flange by a smaller ring of
metal, which is applied over it, & by means of which the flange is held firmly
ngainst the disc. The tube D is fixed into the disc in a water-tight manner, and
a few apertures are made in its base just above the surface of the disc, around which 4
a piece of sponge is bound for the purpose of straining the water before it passes
into the filtering bed. If a plate thus constructed be adapted to a cylindrical vessel
so as to act as a cover for filtering materials placed in the lower part of the same,
as in ordinary domestic filters, the filtering bed is readily accessible by the removal
of the plate, and yet the water cannot pass into the bed without undergoing pre- 5
liminary filtration through the compressed sponge which surrounds the base of the
tube D. This tube need not have an aperture at its top to allow of the entrance
of air to and its exit from the filtering bed if an air passage be made in the wall of
the filter, as is sometimes done
Having thus described separately in all their details the several improvements in 5
which my Invention consists, and also the appliances by means of which the objects

page_text: of the same may be effected, I claim as the novel features of my Invention the
following, viz. :-
(1.) The construction of an improved form of floating filter by the adaptation of
a movable cover of metal or other suitable material fitting in an air-tight manner
by means of an india-rubber flange, to a vessel constructed as shewn in Fig. 1,
which is connected at its outlet with an elastic tube of such a length as to act as a
syphon, and to which is attached a screw clip or other convenient means of regu-
lating the flow of liquid through the filter, the same vessel being capable of being
used also as an immersion filter, and by downward action in the way herein-before
described.
(2.) The construction in the way herein-before described of improved vessels for
filtration, as shewn in Figs. 2 and 3, and especially the use in the construction
thereof of a movable air-tight fitting cover, of a similar kind to that referred to in
claim 1, adapted to the upper aperture of the vessel containing the filtering mate-
rials, so that the same may be readily exposed for the purposes of inspection,
aeration, or cleaning, and also of a means of regulating the flow of liquid through
such vessels by a screw clip fixed on a piece of elastic tubing, taper screw fitting in
the end of a pipe or other similar appliance.
(3.) The improvement of ordinary downward-acting cylindrical filters by the
adaptation to them of the plate as a cover of the filtering bed, constructed in the
way herein-before described, which whilst it prevents the entrance of liquid to
the filtering bed, except after undergoing preliminary straining, can be easily
removed to allow of the exposure of the filtering bed for purposes of inspection or
cleaning.
In witness whereof, I, the said Francis Thomas Bond, have hereunto set my
hand and seal, this First day of June, in the year of our Lord 1878.