CERTAIN IMPROVEMENTS IN APPARATUS FOR THE FILTRATION OF FLUIDS
Year: 1866

page_text: LETTERS PATENT to Paul Rapsey Hodge, of Number 106, Cannon Street,
in the City of London, Civil Engineer, for the Invention of "CERTAIN
PROVISIONAL SPECIFICATION left by the said Paul Rapsey Hodge at
the Office of the Commissioners of Patents, with his Petition, on the
1st October 1866.
I, PAUL RAPSEY HODGE, of Number 106, Cannon Street, in the City of
London, Civil Engineer, do hereby declare the nature of the said Invention
for "CERTAIN IMPROVEMENTS IN APPARATUS FOR THE FILTRATION OF FLUIDS," to be
as follows:-
My Invention relates to certain new constructions and conformations in
filters for the cleansing of fluids, and also in the use of certain chemical and
mechanical mediums in the filtration of fluids.
Figure 1 is a sectional elevation of a duplex filter for filtering fluids, both
by the ascending and descending columns, the first by the pressure of the
column used, and in which is the rapid filter for general purposes; and,
secondly, by a descending column, which effects a second filtration.
It will be seen by reference to Diagram, Figure 1, that the water passes
from the main under pressure to the pipe A into the chamber B, and
through the prepared medium C, which is of any fibrous material stretched
tight over the frames D, so that the water passes through this medium before

page_text: "
it comes into contact with the chemically prepared medium E, and the gravel
E', and the carbon F, in the ascending column of the first filter. This medium
is made of any vegetable or animal fibre, and is prepared with "tannin," or
solutions of "tannin" and iron, which preparations have an affinity for organic
matter which arrests in its course the larger particles of feculent vegetable or
animal matter, animalculæ, earthy matter, or anything that may be in sus-
pension in the fluid to be filtered. I also place fibrous or woody matter
saturated with sulphate of iron in solution, which is afterwards washed with a
solution of chloride of lime, when it is afterwards exposed to the action of the
atmosphere and oxadized, making it a protochloride or a perchloride of iron.
Another method of saturating the above materials will be by first steeping
them in a solution of sulphate of iron for some time, and then washing them
off with a weak solution of nitric acid, and afterwards expose to the air for
oxidasition; or 1 first saturate the above fibrous materials with a solution of
"tannin
or "tannic acid" and then immerse them in a solution of sulphate
of iron, making a "tannate of iron," either of which will have an affinity for
organic matter. By placing them in the chamber E at the back of the
medium C, or in any portion of the ascending or descending columns sepa-
rately, or in combination with the carbonaceous material, for the purpose of
arresting and decomposing the finer portions of organic matter that may pass
through the first fibrous prepared medium, as before described; therefore
nothing but the very finest particles that may pass through these mediums
remain to be purified and arrested by the first column of carbonaceous or
other material. This completes the first filtration for all ordinary uses, which
is drawn off from the chamber G through the tap H. The fluid for drinking
purposes is again filtered by its own gravity from the chamber G down
through a second column of carbonaceous or other material in combination,
and then into the lower chamber J, which fluid would be thus filtered through
four mediums, and thereby divested of all matters injurious to health. The
arresting chamber B, over which is stretched the prepared medium C, this
will "choke up," and must be cleansed on its surface periodically, dependant
on the amount of feculent organic animalculæ or earthy matter in suspension
in the fluid. The surface of this medium is cleansed by a revolving brush K
attached to a spindle L passing through a stuffing box M, and to which is
attached a handle N, so that by opening the lower "drain tap" O and turning
the handle N the medium is brushed clean and the impure matter runs off
through the waste pipe, preventing at any time any of the grosser particles of
matter from entering the filter. Instead of the revolving brush I use a vertical
brush, if necessary, as shewn in Figure 1, a, the spindle L' passing through

page_text: the stuffing box M¹, being worked in a vertical direction, the foul matter is run
off, as before described, through the waste pipe O¹, so that the ascending and
descending columns containing the mediums herein described will never
"choke up" (which is not the case with filters now in use), thus cleansing
the fluid of all matters in suspension both by mechanical and chemical
means.
Chapter 2. Another and cheaper form of filter, embodying the same
chemical and mechanical mediums, adapted to ordinary household purposes is
shewn in Figure 2. This filter is somewhat similar to the ordinary descending
filter, save in the provision made to catch the particles of feculent and
organic matter by my chemically prepared mediums; first, in the form of a
bag P; and, secondly, in a loose fibre chemically prepared, which is shewn
marked P¹; this bag is "slipped on" with an elastic cord Q around the upper
edge of the filter; when this bag is "choked up" and will no longer let the
fluid pass through it we take the bag off, wash it clean, and return it to the
filter again, as before described. I also place (chemically prepared) woody
or fibrous material, as marked P¹, or any porous matter charged with any of
the before-mentioned chemical compounds, and place them immediately below
the bag P, so as to arrest any organic matter that may pass through it before
entering the filtering material in the lower chamber.
Chapter 3. My next form of filter is shewn in Figure 3, which is a
"cistern filter" immersed in the fluid. The first filtering medium R is of
cloth chemically prepared, which is fastened around the edges of the filter S, S;
in the centre of this cloth is affixed a wood flange T, and on to this is attached a
rod U which when pulled up and fastened with the pin V strains the prepared
cloth tight (as shewn in the Drawing); the fluid passes through this medium
in the direction of the arrows, arresting the particles of matter as before
described; it then descends through the first column of carbonaceous or other
materials W, it then passes out through the perforated bottom X, and ascends
through another column of filtering material Y into the water chamber Z;
the fluid can then be drawn off through the pipe a'. Should the medium R
want cleansing I take out the pin V, give the rod a rapid up-and-down motion,
which." flaps" the cloth, throwing off the particles of matter which chokes it
up, when the water will pass through it as before.
Chapter 4. Figure 4 represents another form of "cistern filter" where
the fluid passes through the tightened filtering medium under the bottom of
the filter (inverting the former arrangement), the fluid ascends through a
column of filtering material a" into a chamber 6", and out through the pipe c".
If the filtering cloth or medium requires cleansing I have a wooden rod e

page_text: attached in the centre to a wooden flange f" as before (only inverted); the
rod passes up the tube g" and is fastened down by the pin h"; by releasing
this pin and giving an up-and-down motion to the rod the whole of the
particles of matter "choking up" the cloth will be thrown off, as before
described, when the water will again flow through in the direction of the
arrows.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Paul Rapsey Hodge in the Great Seal Patent Office on the
1st April 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PAUL
RAPSEY HODGE, of 106, Cannon Street, in the City of London, Civil Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of October, in the year of our Lord One
thousand eight hundred and sixty-six, in the thirtieth year of Iler reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said Paul
Rapsey Hodge, Her special licence that I, the said Paul Rapsey Hodge,
my executors, administrators, and assigns, or such others as I, the said
Paul Rapsey Hodge, 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 vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "In-
PROVEMENTS IN APPARATUS FOR THE FILTRATION OF FLUIDS," upon the condition
(amongst others) that I, the said Paul Rapsey Hodge, my executors or
administrators, by an instrument in writing under my, or their, or one of their
hands and seals, 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 Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Paul Rapsey Hodge, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement
Chapter 1-My Invention relates to certain new combinations and
arrangements in the construction and conformation of filters for the cleansing

page_text: of fluids, and also in the use of certain chemical and mechanical mediums
used separately or in combination for the filtration and decomposition of all
impurities contained in fluids. Other advantages are in the arresting of all
larger particles held in suspension and not allowing them to enter the body of
the filter; such particles, when arrested, are by the peculiar mechanical
arrangement of such filtering mediums drawn off; the fluid is then passed
into the filter to be acted on by the chemical and mechanical combinations
therein contained. The nature of these improvements will be better under-
stood from the accompanying Drawings, with their letters of reference.
It will be seen in Figures 1 and 2, Sheet 1, that the water passes from the
main under pressure through the pipe A into the chamber B, and through the
chemically prepared medium C (as will be hereafter explained); this medium
is made of any fibrous material stretched tight over the frames D, so that the
water or other fluid pass through this medium before it comes into contact
with another chemically prepared medium E and the gravel or granulated
broken potters' ware E¹, and the carbon F in the ascending column of the
first filter; this passes off into the cistern G through the overflow pipe H,
which is regulated by a ball-cock or any other suitable hydraulic regulator, so
as to keep the line of fluid to a defined height in the body of the filter ; this
process is what I term my rapid filtration, and may be used for all ordinary
purposes, being fully divested of all its feculent matter and such impurities as
are essential to be abstracted from the water for culinary purposes. I then
pass the fluid by its gravity down through the gravel J and. prepared fibrous
material K into the filtering strata L and M, and then into the oxidising
chambers N, and thence into the chamber N¹. The oxidising chambers are
suspended from the partition O, and may be of any convenient size and
number, and are filled usually with the best prepared animal charcoal, but not
so compact as the other filtering mediums above; the sides of these chambers
N are perforated and the water allowed to pass freely through them, by this
immersion of animal charcoal or other compounds, either separate or in com-
bination, I take all organic matter and other impurities held in suspension
from the fluid in the chamber N' and make it perfectly pure for use; henco
we have a combination of a rapid filter which can be used where there is a
pressure of (at least) two feet above the top of the filter, and a descending filter
which doubly purifies the fluid. By reference to the chamber B it will be
seen that there is a brush made of split bass or any other elastic fibre that will
not decompose by the action of the water; this brush has a spindle O passing
through the shifting box P, on the outer end is a handle Q, so that whenever
the filtering medium C is choked up the waste tap R is opened and the handle

page_text: turned around, thereby brushing the surface of the filtering medium; all the
dirt and filth passes off through the lower tap R, and the filtering medium is
again ready to pass fluid through for another period, thereby preventing any
of the larger particles of matter from ever entering the filter, and at the same
time having the property of self-cleansing.
Figure 3 represents other forms of cleansing chamber with an horizontal or
vertical movement to the brush instead of the rotary movement above
the
described, the chamber being a square box instead of a circular one;
brush C' impinges against the medium C, and is operated on by the handle.
which is
Figure 4 represents another chamber with a distended bag
operated on by the rod O, when motion is given to it; when the waste pipe is
pen and the back pressure cleanses the medium, as in Figure 1, these
chambers and fibrous arresting mediums can be placed in any convenient
position, either horizontal or vertical. The cleansing of the medium in
Figure 1 may be effected by merely closing the tap A and opening the waste
pipe tap R, when the pressure from the filter will cleanse the surface of the
filtering medium by the reversed current.
Chapter 2. Another form of filter is represented in Figure 5, which
embodies all the elements of the filter previously described, but operate on the
descending principle only. A, A, the body of the filter, which is similar to
filters now in ordinary use in its outward conformation, save that it is much
larger in proportion to its diameter; B, B, the top chamber, in which is sus-
pended a chemically prepared bag C, C, passing over the outer edges D, D,
and is held fast by means of an elastic band E, E; this bag is chemically
prepared and made of the same material as the medium previously described
in Chapter 1. The fluid to be filtered is poured into this bag, and percolates
through the fibre into the chamber B, catching or arresting all larger particles
of matter, such as moss, worms, mud, and organic matter in suspension, so
that the filter has nothing to do but to oxidise the smaller particles of organic
matter by passing through the gravel F and cloth medium G, and down into
the animal charcoal H, and through the final purifier or oxidiser J, and thence
through the perforated sides K, K, into the lower water chamber L, L; this
oxidiser or purifier, with its carbon, is constantly present and acting on the
filtered water until it is drawn off.
Chapter 3. Another form of filter is shown in Figure 6, which embodies
all the principles and elements of those previously described, but is immersed
in the fluid in an ordinary cistern. A, A, the cistern; B, B, the body of the
filter; C, C, the fibrous chemically prepared medium fastened all round the
outer edges D, D. In the centre of this bag is fastened a wood rod E by

page_text: the washers F, this bag is distended by pulling up the rod, and fastening it
with the pin G at the top. The water percolates through this fibrous medium,
which arrests the particles of matter as before described, thence passes through
the descending column of carbon and other filtering mediums, out through
the perforations H, H, at the bottom, and up through the annular chamber of
carbon I into the water chamber J, and is drawn off through the pipe K.
Figure 7 represents another cistern filter similar to the one in Figure 6,
but the bag or filtering fibrous medium, is underneath, the fluid entering the
filter upwards through the medium, as shewn by the direction of the arrows.
The rod E which disturbs the bag passes freely through an iron tube F, and
is fastened to the bag by the washers G, and held down at the top to keep
the bag distended, as in Figure 6 (only inverted). The fluid passes up in
the direction of the arrows through the ascending column of carbon and other
filtering materials, and into the water chamber J, and is drawn off through
the pipe K.
Chapter 4. Another form of my self-cleansing filter is shewn at Figure 1,
Sheet 2, which is particularly adapted to the filtration of water for the supply
of towns or breweries where now large areas of sand filtering beds are used.
Figure 1 represents a section of my self-cleansing filter. A, A, the casing,
which is of any suitable material; B and B', the bottom and top covers;
C and C, two cloth diaphragms prepared with tannin as described, which are
fastened around the edges on the perforated platforms D and D', and distended
by the rods E and E¹, passing through stuffing boxes in the covers; outside
of which the rods are fastened by a pin or other means at a point to keep the
filtering diaphragms C and C¹ perfectly tight. The water passes through
these diaphragms in the direction of the arrows, and enters top and bottom
through the central ingress pipe F and up to the top, and down to the bottom
through the pipes G and G¹, thence through the mediums C and C, in the
direction of the arrows; thence down and up through the perforated plat-
forms D and D, and through the filtering mediums J, J, and J, J¹, and out
through the platforms K and K' into the central egress chamber L, and
through the egress pipe M, when the fluid is perfectly filtered. In order to
cleanse this machine I cause it to hang on hollow centres supported by
the bearings on the top of the two frames N and N¹, so that it can be turned
over at pleasure. When the filtering diaphragms C, C', get choked up
(top and bottom), I take the pin P out of the bottom rod, and relax the
diaphragm C with the rod E; I give it an upward and downward motion,
and as it were "flop" the medium C at the same time. I open the waste or
mud tap R, and wash it through by the water passing from the top and out

page_text: through the filtering diaphragm C, thus cleansing the lower half; I then
swing the whole apparatus over, and turn the top to the bottom, and bottom
to top, and clean and wash through the other half in the same way, when the
filter is again ready for use. When the filtering medium is in any way choked
up by reason of any organic matter being in the carbon, or gravel or prepared
mediums, I take a jet of steam or boiling water from the pipe S and pass it
through both the bottom and top halves of the machines when the whole
may be washed through with cold water, and again ready for use.
I make a
filter also on this principle by only using the lower half, and not swinging it
on trunnions as above described, and bringing in the water at the bottom as
before described, and passing it off from a chamber at the top. The great
element in this kind of filter is the use of the prepared filtering diaphragm
arresting the larger particles of matter, and also the method of cleansing it,
and discharging such matter without its going into the filtor.
Chapter 5. In either of the filters previously described in Chapters 1, 2,
3, and 4 the chemically prepared mediums are of any fibrous material, but
from long experience in these matters, and after numerous experiments, I find
nothing so god as cotton or linen fibre, either woven or inserted in a chamber
in a spongy form. I take the medium cloth C or bag, as described in Figures
4, 5, 6, & 7, and immerse it in tannin liquor for at least thirty days, when it is
perfectly tanned ready for use, and not liable to decompose. The mediums E
and E in the chambers, Fig. 1, 3, 4, I prepare by taking carded cotton wool,
which I first immerse into a solution of sulphate of iron until the interstices of
the fibre is thoroughly impregnated; I then immerse it in a weak solution of
chloride of lime, which converts the sulphate into a perchloride of iron; it is
then washed clean, and exposed for some time to the action of the atmosphere,
and then placed in the chambers for use as described.
Another method is by taking the vegetable fibre and saturating as before
in a solution of sulphate of iron as described above, I then wash it off in a
weak solution of nitric acid, or I take sawdust or cork chippings, and saturate
it in the same way as the vegetable fibres as before described, either of which
have an affinity when prepared thus for organic substances, and are useful in
addition to the animal or vegetable charcoal for the oxidising and taking up
of any organic matter that may be in the fluids to be filtered.
Having thus described the nature and particulars of my said improvements,
I desire it to be understood that I do not confine myself to the exact details
herein described, as such may be varied and modified without departing from
the principles thereof; but which I claim as new and of my Invention is the
combination, conformation, and arrangement mechanically and chemically of

page_text: the duplex cleansing pressure filter, as described in Chapter 1, and shewn in
Figures 1, 2, 3, and 4, Sheet 1.
Also the arrangement, conformation, and combination of the chemically
prepared bag filter with the oxidising chamber, as shewn in Figure 5, and
described in Chapter 2.
Also the combination and arrangement of the cistern filters on the ascending
and descending principle, with the distended chemically prepared arresting
medium or diaphragm, and the manner of cleansing the same, as shewn in
Figures 6 and 7, Sheet 1, and described in Chapter 3.
Also in the combination and arrangement of the duplex oscillating filter
with its arresting mediums, and method of cleansing the same, and also in
purifying, recussitating the filtering compounds contained therein by hot water
or steam, as shewn in Figure 1, Sheet 2, and fully described in Chapter 4.
Also in preparing fibrous material or other vegetable compounds with
tannin and other chemical matters for the especial uses set forth in this
Specification, and especially described in Chapter 5.
In witness whereof, I, the said Paul Rapsey Hodge, have hereunto set
my hand and seal, this First day of April, in the year of our Lord
One thousand eight hundred and sixty-seven.
PAUL R. IIODGE. (L.S.)