IMPROVE- MENTS IN THE MODE OF AND APPARATUS FOR FILTERING WATER AND OTHER FLUIDS:
Year: 1866

page_text: LETTERS PATENT to Thomas Spencer, of Euston Square, in the County
of Middlesex, Chemical Engineer, for the Invention of "IMPROVE-
MENTS IN THE MODE OF AND APPARATUS FOR FILTERING WATER AND OTHER
FLUIDS:"
Sealed the 3rd July 1866, and dated the 5th February 1866.
PROVISIONAL SPECIFICATION left by the said Thomas Spencer at the
Office of the Commissioners of Patents; with his Petition, on the
5th February 1866.
.
I,.. THOMAS SPENCER, of Euston Square, in the County of Middlesex,
Chemical Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE MODE OF AND APPARATUS FOR FILTERING WATER AND
OTHER FLUIDS," to be as follows:-
Being desirous of performing the double purpose of filtering from above and
below (that is, by descension and ascension) in one and the same operation,
I adopt the arrangement shewn in the accompanying Drawing, of which the
following is a description.
In Fig. 1A represents the section of a tile of a proportionate thickness
of earthenware or flag, with a hole or perforation in the centre; B; the section
of a hat-shaped piece of earthenware or other suitable material, which must
contain a series of holes or perforations near its crown, the size and number
of which are regulated by the quantity of water or other fluid required to
be filtered in a given tille. B is fastened on the tile A, but over the perfora-

page_text: tion of the same, with Portland or other suitable cement. Crepresents
the section of a jacket or covering of earthenware or other suitable material,
which must be placed so as to envelope the upper portion of the hat-shaped
piece B, and made to rest on the upper side of its flat rim. The space
between B and C is to be filled in with fine gravel, though not so fine as
to allow any of its granules to pass through the holes or perforations shewn
near the crown of the hat-shaped plate. C is then to be fastened to B with
Portland or other cement, as shewn by the surmounting plug or
bat of cement at D. The combined apparatus thus arranged is
then to be placed at given intervals on the covered drains of a
filtering bed or tank to be constructed at the bottom or lower level of the
same, the tile part of the arrangement being substituted for and made to
serve as one of the covering tiles of the said drain.
In order that the process
of filtration shall proceed with regularity and without obstruction, it is necessary
that the bottom or lower edge of C, which rests on the rim of B, shall have
on it a series of small channels or corrugations to permit the water to pass
through, but which shall at the same time prevent any of the surrounding
material from passing along with it. These channels are shewn in the radial
lines of Fig. 2 on the Drawing. The arrows on Drawing Fig. 1 shew the
direction of the water or other fluid when the apparatus is in operation. It
will be obvious to those in the least degree acquainted with the ordinary
modes of filtration that the apparatus here described may be made
to any suitable dimensions. For example, those shewn in the
Drawing may be made smaller or
or considerably larger, though I find
rule that it is not convenient that the size of the perforated
tile should exceed twelve inches square, and which regulates the dimen-
sions of the other parts of the arrangement. It may be necessary to add
that the apparatus when fastened over the drain in the filter is then surmounted
to any required thickness with gravel, sand, or carbide of any of the ordinary
and well-known filtering media.
SPECIFICATION
in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Spencer in the Great Seal Patent Office on
the 4th August 1866.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of February, in the year of our
Lord One thousand eight hundred and sixty-six, in the twenty-ninth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Thomas Spencer, Her special licence that I, the said Thomas
Spencer, my executors, administrators, and assigns, or such others as I, the
said Thomas Spencer, 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 "IMPROVEMENTS IN THE MODE OF AND APPARATUS FOR FILTERING WATER AND
OTHER FLUIDS," upon the condition (amongst others) that I, the said
Thomas Spencer, 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 Thomas Spencer, 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,
reference being had to the Drawings hereunto annexed, and to the letters and
figures marked thereon (that is to say):-
OBJECTS OF THE INVENTION.
Mechanical impurities are usually removed from water and other murds by
being made to pass through successive layers of sand and gravel or other
similar material. Sometimes the fluid is made to ascend through the filtering
media from below, but it is more generally made to pass from above downwards,
and thereby leave its impurities on the uppermost layer of the filtering media.
Though in the ordinary downward system the whole of the actual work of
filtration is apparently performed at the surface of the upper or intercepting
layer (usually one of fine sand), yet a series of thick graduated masses of coarser
material have always been found indispensable in order to act as retarding
or frictional media to prevent the water from passing too quickly at the surface
of the upper layer. Without the frictional intervention of the lower
layers to operate thus indirectly the lighter particles of suspended
purities are usually removeu
Dy
being made to pass through successive layers of sand and gravel or other
similar material. Sometimes the fluid is made to ascend through the filtering
media from below, but it is more generally made to pass from above downwards,
and thereby leave its impurities on the uppermost layer of the filtering media.
Though in the ordinary downward system the whole of the actual work of
filtration is apparently performed at the surface of the upper or intercepting
layer (usually one of fine sand), yet a series of thick graduated masses of coarser
material have always been found indispensable in order to act as retarding
or frictional media to prevent the water from passing too quickly at the surface
of the upper layer. Without the frictional intervention of the lower
layers to
to operate thus indirectly the lighter particles of suspended

page_text: matter would be carried through the top one, and thereby render the filtering
operation of little value. With the object of diminishing the thickness of
this lower mass of retarding or filtering media, which apart from
its own cost involves considerable increase in that of the reservoirs
to contain it, a system of upward filtration has been often tried
and nearly always abandoned on its being found to require the
removal of the whole of the filtering media whenever the intercepting layer
at the bottom requires cleansing. Though this latter system has some advan-
tages, yet by the downward one the process of cleansing is so easily effected
by the removal of a thin layer of the top sand only, and which contains all
the suspended impurities, provided the retarding or frictional layers are of
sufficient thickness, but not otherwise. The balance of convenience being
thus found to predominate in favor of the downward system, notwithstanding
its greater expense at the outset, it is now in general use in most waterworks
where filtration is practised.
In order to combine the advantage of both of these systems of filtration,
and at the same time to diminish the immense mass of material required
for the ordinary downward one, I have devised the mode I am about to
describe, in which both systems are made to operate together, as shown in
the accompanying Drawings. As only half the ordinary quantity of filtering
media is required, and if need be still less, the new mode has not only the
advantage of this great economy, but the operation of filtering is in itself
necessarily much better performed than if the intercepting media were double
the thickness. The lesser thickness of material required involves not only
its own saving but at least one-half of the cost of excavation and brickwork,
because of the depth of the walls being so much less; whilst the process itself
operates best with only a small head of water in the filter bed. The latter
is also of considerable advantage, where from the level character of the ground
little fall can be obtained without considerable expenditure of steam or other
power.
It will be seen on the Drawing that by the apparatus placed on the drain at
the bottom of the filter the downward rush of the water is so effectually
regulated or balanced by its ascension upwards as to allow of a more complete
interception of the suspended matters, and also to prevent all choking of the
interior. In my system the water descends through the sand not, as usual,
in straight but in a series of conoidal lines intersecting each other, and which
converge below at the regulating or balancing apparatus, where the water
is then bent upwards, as in a spring, before it reaches the lateral drain at
the bottom of the bed. By these means no more than a certain quantity of

page_text: water can ever pass through the apparatus at any point in a given time, which
greatly contributes to keep the surface of a filter bed free from hollows
where a series of the
series of the apparatus
apparatus are in operation together, whilst
it promotes at the same time the quiet interception of the
lighter particles of suspended matters on the surface of the fine sand
at the top.
To understand the improvement effected by this system it is necessary
to bear in mind that what I term retarding layers are in ordinary con-
structed filter beds placed for the sole purpose of acting in opposition to
or partially overcoming the downward gravitation of the water, in order
that the lateral attraction between the water and the media itself may
be allowed to operate, consequently any arrangement that shall bend or retard
the flow of the water in its downward passage necessarily promotes the attraction
of the suspended matters to the sand at the surface, and thus prevents the
same from being carried down along with the water. In short, it is to the
attraction of the sand for the lighter matters which are in suspension (which
are usually smaller than the interstitial spaces of the sand) that mechanical
filtration is due. Hence arises the necessity for the thick masses of filtering
media which are in filter beds of the ordinary construction, but which by this
Invention are rendered unnecessary.

page_text: The space between B and C is to be filled in with fine gravel, but not so
much so as to allow any of its granules to pass through the holes or per-
forations shown near the crown of the hat-shaped plate. C is then to be
fastened to B with Portland or other cement, as shewn by the surmounting
plug or bat of cement at D. The combined apparatus thus arranged is
then to be placed at given intervals on the covered drains of a filtering
bed or tank to be constructed at the bottom or lower level of the same,
the tile part of the arrangement being substituted for and made to serve as
one of the covering tiles of the said drain. In order that the process of
filtration shall proceed with regularity and without obstruction, it is
important that the bottom or lower edge of C, which rests on the flat rim
of the hat-shaped plate B, shall have on it a series of small channels or
corrugations to permit the water to pass through, but which shall at the
same time prevent any of the surrounding filtering material from passing
along with it. These channels are shewn in the radial lines of Fig. 2 on
the Drawing. The arrows on Drawing Fig. 1 show the direction taken
by the water or other fluid when the apparatus is in operation. It will be
obvious to those in any way acquainted with the ordinary modes of filtra-
tion that the apparatus here described may be made to any suitable
dimensions, according to the quality of the water to be filtered. For
example, those shown in the Drawing may be made smaller for the purpose
of domestic filtration, or considerably larger, though I find as a rule that it is
not convenient that the size of the perforated tile should exceed twelve
inches square, and which regulates the dimensions of the other parts of the
arrangement. It may be necessary to add that the apparatus when fastened at
any given interval over the drain in a filter bed or tank is then surmounted
to any required thickness with gravel, sand, or of any filtering or
purifying media. The quantity of water which shall pass through each
apparatus is obviously regulated by the number and size of the holes in the
hat-shaped plate B, and also by the depth of the corrugations on the lower
edge of C.
Having described the nature of this Invention, I may state that I am
aware that filtration has already been practised by means of perforated
tubes or pipes of earthenware of various shapes placed at the bottom of
the filter to allow of the passage of the water into the drain or clear water
chamber as the case may be; but what I claim as my Invention is the
covering or jacket C with a corrugated rim, as shown in Figures 2 and 3
in the accompanying Drawing.

page_text: I may add that I do not confine myself to the shape of the said covering
or jacket, or the size and number of the corrugations in its rim, but I may
state that the latter ought not to be so large as to allow of the passage of
ordinary sand.
In witness whereof, I, the said Thomas Spencer, have hereunto set
my hand and seal, the Fourth day of August, in the year of our
Lord One thousand eight hundred and sixty-six.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
THOMAS SPENCER. (L.S.)