CERTAIN IMPROVEMENTS IN APPARATUS FOR PURIFYING WATER
Year: 1863

page_text: LETTERS PATENT to Frederick Ludwig Hahn Danchell, of Red Lion
Square, in the County of Middlesex, Civil Engineer, for the Invention of
*CERTAIN IMPROVEMENTS IN APPARATUS FOR PURIFYING WATER."
Sealed the 29th Decomber 1863, and dated the 21st July 1863.
PROVISIONAL SPECIFICATION left by the said Frederick Ludwig Hahn
Danchell at the Office of the Commissioners of Patents, with his Petition,
on the 21st July 1863.
1, FREDERICK LUDWIG HAHN DANCHELL, of Red Lion Square, in the County
of Middlesex, Civil Engineer, do hereby declare the nature of the said
Invention for CERTAIN IMPROVEMENTS IN APPARATUS FOR PURIFYING WATER," to
be as follows:-
This Invention consists in certain improvements in apparatus forpurifying
water, firstly, by means offiltration; secondly, by means of precipitation; and
thirdly, by precipitation and filtration combined.
Having found by experience that a former Invention of certain improve.
ments in filters patented by me the Sixteenth day of February, in the year
One thousand eight hundred and sixty, No. 1712, was imperfect in its action
without certain arrangements to regulate the speed of the filtration according
to the nature of the water and the impurities contained therein, I now wish to

page_text: power of the parties concerned to regulate the speed of the water passing
through the said filter as may be deemed necessary. This constitutes the first
part of my Invention, and is effected by a mode of obstructing the free passage
of the water either when entering into the
filter or when passing out, or in both cases.
The mode which I prefer is that of a set
screw applied, as shewn in the annexed
Diagram. The further the screw is set the
greater is the obstruction, and the less water will be able to pass, and vice
versa.
The second part of my Invention consists in causing certain matters in
solution in the water to become insoluble and to settle as a precipitate at the
bottom of the vessel or vessels containing the said water. For this purpose I
mix with the water to be acted on caustic lime and carbonate of soda in certain
proportions, that is, 1 part ofa strong solution of carbonate of soda to 32 parts
of water saturated with lime. The mixing of these said ingrediences with water
I cause to take place in a vessel which is connected with another at the bottom,
so as to admit the said water to pass from the one into the other, thereby
causing the pure water to ascend, leaving the heavy matter as a precipitate at
the bottom.
The third partof my said Invention consists in applying both these modes of
purifying the water simultaneously, so that those impurities which are not
affected by the one may be acted upon by the other. For this purpose I
arrange the filter to be fixed in the upper part of the vessel containing the
water which has been purified by precipitation as above described, so that the
water, after having discharged its mineral salts, cair pass through the filter and
made to leave behind its organic impurities.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frederick Ludwig Hahn Danchell in the Great Seal Patent
Office on the 20th January 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
LUDWIG HAHN DANCHELL, of Red Lion Square, in the County of Middlesex,
Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of July, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-seventhycarof Her

page_text: reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Frederick Ludwig Hahn Danchell, Her special licence that I, the
said Frederick Ludwig Hahn Danchell, my executors, administrators, and
assigns, or such others as I, the said Frederick Ludwig Hahn Danchell,
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 "CERTAIN IMPROVEMENTS IN APPA-
RATUS FOR PURIFYING WATER," upon the condition (amongst others) that I, the
said Frederick Ludwig Hahn Danchell, 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 mannerthe same was to be perforined, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Frederick Ludwig Hahn Danchell,
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 and accompanying Drawings, that is to say:-
It has generally been supposed that the pores in a filtering material in order
to arrest minute particles in suspension in water ought to be smaller than the
smallest particles to be arrested. This theory, however, is erroneous, from the
fact, that in this case, as cach particle would stop up a pore, all the pores on
the surface of the filtering material would be closed after the first time of
filtering any impure water; also, that if the pores or passages in the filtering
material were to be so small er smaller than the smallest particles in suspen-
sion, many of which are only visible with a microscope; then the capillary
attraction would be so great that even the water alone could not pass except
by means of considerable pressure. It is therefore not the narrowness of the
passages or pores which retain the minute bodies, but the attractive force of
the filtering material; and the size of the pores only in so far influences the
process as it determines the speed with which the water will percolate through
the filtering medium, and leaving the attractive force to exercise its power
more or less undisturbed. The narrower the passages are the slower will be
the flow of the water, and consequently the less the attractive force is inter-
fered with and the more perfect the filtering will be. Fine porous material is
not then the direct cause of perfect filtration, but only indirect in so far as it
affects the speed; the great drawback, however, is that the pores easily become

page_text: clogged and prevent the water from percolating through the material at all.
To obviate this and at the same time to give the flow of the water a speed that
will not destroy the attractive force, is the object of one part of my Invention,
and is effected in the following manner: -1 avail myself of a vessel or jar of
earthenware or other suitable material (see Fig. 1, 2, and 3) the bottom of
which (a) is perforated; the top is closed air-tight with a cover (b); (c) is a
strainer to prevent the filtering material from passing away with the water.
The said vessel or jar is entirely filled with my filtering material which may
be considered the best adapted for the purpose. I prefer animal or bone
charcoal coarsely granulated (about 1 to of an inch cubical). (d) is the
pipe for the exit of the water; (c) may be either a screw or tap or any other
contrivance for the purpose of narrowing the passage through which the water
has to flow, and by that means to regulate the quantity of water which is to
pass through the pipe,and consequently also the speed of the flow through the
filtering material.
Instead, therefore, of adopting a filtering material with sufficiently fine
pores to give the flow the required speed without destroying the proper action
of the attractive force, I adopt a coarse material which will admit the passage
of the water very freely, and regulate the speed by means of the screw or tap
(e) above described. In this case the filter will continue to perform its duty
for a much longer period without the passages of the water becoming obstructed.
In cases where large quantities of water are required, such as for manufac-
tories, waterworks, and other establishments, I adopt the same arrangement,
only that I modify it according to each particular case.
Besides the impurities in mechanical suspension there are often matters in
solution which it is desirable that the water should be freed from, such as
earthy silts, metallic oxides, and organic matter. For this purpose it is gene-
rally necessary to apply some chemical means to effect a precipitation of the
matters in question, and a great variety of different means has been proposed,
many of which have some time or other been patented; but the reason why
they have been so little introduced practically has generally been the time they
require to effect the precipitation.
The means to meet this objection constitutes the second part of my Inven
tion. I construct a cistern, tank, or water holder in the manner as shown in
Fig. 4. (p) is the service pipe supplying the water from the main into the
tube T, into which also are introduced the chemical ingredients chosen to pre-
cipitate the matters in solution. The said precipitate is carried with the water
to the bottom of T, and whilst the water passes through the connection V to
the tube T in which it ascends, the precipitate remains behind at the bottom

page_text: of T, T, and V. One of the matters in solution in water most frequently met
with is bicarbonate of lime. Dr. Clark, of Aberdeen, has discovered a means to
precipitate this substance by an admixture of caustic lime. To employ this
means practically I have constructed the following apparatus, Fig. 5, in which
consists the third part of my Invention. (r) the cistern is provided with two
partitions (a) and (b), (a) contains the precipitating medium, slaked lime;
(b) contains in a separate casing the filtering material, which consists ofanimal
or bone charcoal, which, as stated above, I prefer to any other. (w) is a flat
box with an outlet or spout (1) through which the water flows from W
into T; (m) is a tube communicating with (m) inside the compartment (a);
(m) has an opening (o) on one side to allow the water to pass down into the
bottom of (a); (o) is on a level with the spout (/), and is made with a slide
to be contracted or enlarged to regulate the quantity of water flowing down;
(n) is an outlet or spout, causing the water which rises in (a) to flow over
into (T.) The compartment (a) having been previously filled with slaked lime
up to about one-third of its depth, causes the water entering into it through
(m) to become impregnated with caustic lime. This impregnated or lime
water flowing over the spout (n) and mixing with the water from the spout
(1) in the tube T, causes the lime in the water to precipitate in form of car-
bonate of lime at the bottom of T, whilst the water alone, without the precipi-
tate, ascends through T into the cistern or tank. The ascending water rising
above the partition of the compartment (6) fills this compartment, and entering
the filter (p) through the holes (9) rises through the filtering material until
it reaches the strainer and pipe at (), from whence it will flow after having
been deprived of its carbonate of lime, its organic matter in solution, and solid
particles in mechanical suspension. The precipitate collecting in V will consti-
tute a filtering material in itself, but iu cases where it is found expedient,
animal charcoal or any other filtering medium may be introduced in this part
of the apparatus to assist in the purification of the water before the filter (p)
is reached, and for which purpose the perforated partition (s) may be provided.
The following three points constitute my claims with regard to this
Invention
1. The application of a screw, tap, or other convenient means to contractor
enlarge the passage of the water either to or from the filter, thereby to
regulate the speed with which the water is to flow through the filtering
medium.
2. The construction of an apparatus as herein-before described to facilitate
and speed the precipitation of matters previously held in solution in the

page_text: ination.
In witness whereof, I, the said Frederick Ludwig Hahn Danchell, have
hereunto set my hand and seal, this Twentieth day of January, in the
year of our Lord One thousand eight hundred and sixty-four.
FREDERICK LUDWIG HAHN DANCHELL. (1..s.)