IMPROVEMENTS IN FIL- TERING AND PRESERVING WATER
Year: 1852

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
PHILIP THOMPSON, of the Waterworks Chambers, Orange Street, Trafalgar
Square, Westminster, in the County of Middlesex, Civil Engineer and Sur-
veyor, send greeting.
WHEREAS Her present most Excellent Majesty, by Her Royal Letters
Patent under the Great Seal of the United Kingdom of Great Britain and
Ireland, bearing date at Westminster, the Second day of February, in the
fifteenth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Frederick Philip Thompson, my exors, adiñors,
and assigns, Her especial license, full power, sole privilege and authority,
that I, the said Frederick Philip Thompson, my exors, admors, and assigns,
or such others as I, the said Frederick Philip Thompson, my exors, admors,
and assigns, should at any time agree with, and no others, from time to time
and at all times during the term of years therein expressed, should and
lawfully might make, use, exercise, and vend, within England, Wales, and
the Town of Berwick-upon-Tweed, my Invention of "IMPROVEMENTS IN FIL-
TERING AND PRESERVING WATER;" in which said Letters Patent there is con-
tained a proviso, that I, the said Frederick Philip Thompson, shall cause a.
particular description of the nature of my said Invention, and in what manner
the same is to be performed, by an instrument in writing under my hand and
seal, to be inrolled in Her said Majesty's High Court of Chancery within six
calendar months next and immediately after the date of the said in part
recited Letters Patent, as in and by the same, reference being thereunto had,
will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Frederick Philip Thompson, do hereby declare that the nature of my Inven-
tion, and the manner in which the same is to be performed, are particularly
described and ascertained in and by the following statement thereof, reference
being had to the Drawings hereunto annexed, and to the figures and letters
marked thereon, that is to say:-
My Invention consists of improvements in filtering and preserving water.
The mode by which this object is effected is by forming a reservoir with a
filter bed over it, covering the entire area of the reservoir. The water being
delivered on the surface of the filtering media, percolates thence to the reser-
voir beneath, which thus becomes a large filtered water chamber; and thus
filtered, the water may be preserved and excluded from all causes of external
contamination. The method of forming this reservoir and filter bed will vary
according to circumstances; that is, when used for public water-works, or for
manufacturing or other purposes; but in all cases' it would be advisable that it
should be divided into compartments, to afford the means of emptying either
compartment if at any time it should be required to enter it for the purpose of
repair or cleansing, likewise to enable this to be done without stopping the
works or the supply; and the capacity of the reservoir should be regulated
for this purpose, or it may be formed without compartments.
Assuming, for instance, that such a reservoir and filter bed were required to be
formed for a public water-works or other works requiring a large supply of clean
water, and that it was determined to construct it on an elevated site, and accord-
ing to such a plan as is shewn on the accompanying Drawing, Figure I., I should
construct it thus :-Excavate the ground to the necessary depth for the bottom
of the reservoir and form flooring of concrete, to be afterwards paved with brick
or other suitable material. This flooring I should construct with channels laid
to an inclination sufficient only to allow a current to the deposit wells, or of an
inclination which I prefer of about half an inch in a length of ten feet. These
deposit wells should be formed at such parts as may be suitable for the purpose
of collecting any grit or other deposit, and the surface of the flooring on each
side of these channels should also have an inclination or fall towards the
channels. In the formation of the concrete, I should always prefer to use
hydraulic limes or cements, and should the nature of the soil on which the
reservoir is made render it necessary, I should lay a bed of puddle clay over
the whole surface before laying the concrete. Proper arrangements having
been made, the division walls should then be formed and constructed of sufficient
strength and height, either solid or cellular, filled in with concrete, or hollow,
to act as filtered water chambers or channels connected with a discharge well.

page_text: I should then have piers built of brick, stone, or other suitable material, at
certain distances apart, and to the height of several feet. These piers should
be then connected by archings of brick, stone, or other suitable material, and
form a connected series of large filtered water chambers, or form as it were a
subteraneous reservoir over the whole area; or they may be constructed with
iron pillars instead of piers and bearers or girders, and with perforated iron
plates or slate instead of the brick archings. These arching may be con-
structed in various ways, but the mode I prefer is either as running from the
sides of the division and surrounding walls, and meeting at a diagonal groining,
as shewn on the plan, Figure I., letter D, and this groining should be so
constructed as to permit the escape of air to the man-holes or shafts provided
for that purpose, or by the mode shewn in the compartment marked N
(Figure 1), where the arches extend from the walls on one side, and terminate
in the arch ×³, which is higher than and runs at right angles to, and admits
the air to escape most readily from the principal arches by the shafts and
man-holes M². These archings may be constructed either of purpose-made
radiated bricks to suit the curve, and with holes in them to allow of the
ready percolation of the filtered water, or they may be made by the common
bricks with open heading joints, to allow ready percolation. I prefer these
joints to be three quarters of an inch wide, but they may be made of other
dimensions. Man-holes or air-shafts may be provided for facilitating repairs
and for the escape of air, and they may or may not be covered. When the
reservoir is full of filtered water, if covered the draught of water from the
discharge pipe Ds (Figure 6) having a tendancy to create a vacuum, will cause
the filter to act more readily, and the deposit wells may be constructed below
them, and be covered with a hinged or moveable iron grating. Where the
locality will permit of it, I prefer in all cases to have drains connected with
these deposit wells, with proper sluice valves for the discharge of the waste
waters, whenever necessary to cleanse the bed of the filtered waters chambers.
The natural ground line of the excavation I prefer to be kept either at the
level or above the line of springing of the arches, and the sides of the reservoir
next the ground or embankments may be lined with concrete and a wall of
sufficient height and strength. The surrounding embankments may be made
in the way embankments for reservoirs are usually made, with puddle banks
and suitable slopes,
It is not, however, absolutely necessary that this mode of constructing a
reservoir and filter bed should be in an excavation, as with proper and suitable
materials it may be built on the surface of the land, or only sufficiently deep in
the soil for proper and secure footings. The division or partition walls may be

page_text: solid, but I prefer those which are hollow, and as being available for retaining
the filtered water; they may be built of brick, stone, or other suitable material
of sufficient strength, and to a height of several feet above the level of the
filtering media, and formed by two walls with a space between. These walls
may be connected at their basis by an invert laid to an inclination sufficient to
create a current, and within a few feet of the top by an arching, which may
from the bed of the supply trough for the distribution of the water on the top
of the filtering media, and the walls may be carried up a sufficient height to
form the sides of the trough, and further strengthened and connected by
strutting arches, proper arrangements being made at the intersections of the
cross division walls; the space between the walls may then act as a filtered
water discharge chamber or channel. It would be advisable that the walls thus
forming a filtered water discharge chamber or channel be connected with a
discharge well, which I prefer to construct at the end of the division wall, or
at such a point as may be in connection with all the divison walls when used
as filtered water chambers; the division walls next each compartment of the
reservoir or filtered water chamber may have openings formed and proper
water-tight sluices of sufficient capacity to allow the free passage of the water
from the chamber under the filtering media, and the sluices should be arranged
so as to stop the flow of the water from them necessary. I prefer to construct
the discharge well of a circular form, with walls of sufficient strength and
height, and with a dome or arched roof; the base to be sufficiently below the
general floor level of the filtered water chambers to allow space for the deposit
of any grit or other matter, and the external walls may be carried up to the
level of the top of the division walls.
The filtering media I prefer to employ is of the description usually adopted
for that purpose when used on a large scale, viz. :-Layers of clean washed
gravel graduated to different degrees of size by passing through different sized
seives for the lower part, and clean washed silicious sand above it, the finest
being at the top, care being taken that these materials should be so deposited as
to form as compact a mass as possible, and offer the greatest resistance to the
passage of the water; and I prefer that the media should form one compact
mass, from two to ten or more feet thick.
The mode of supplying the water to be filtered to this media will vary
according to circumstances, but I assume, as before stated, the reservoir and
filter bed to be constructed on elevated ground, and that the water would have
to be lifted to it by steam or other power.
In describing the construction of the division walls above, it is said the two
walls forming the division walls' may be connected at their base by an invert,

page_text: and within a few feet of the top by an arching, which may form the bed of the
supply trough. To form this supply trough, I fill in concrete level with the
upper surface of the last-named arching and the spandril of the extrados of the
dome of the discharge well, and pave the whole bed of the trough with stone or
other suitable material, but preserving a sufficient inclination to cause a good
current for the water to the ends of the trough when delivered by the raising
main. In the walls forming the sides of the supply trough or troughs, openings
should be left with proper water-tight iron or other sluices for the purpose of
allowing the free passage of the water on to the media, and the sluices to shut
it off when required. The sluices should be constructed with all necessary
rods, pinions, and apparatus for either opening or closing them, as is usual for
such works: The lip of these sluices I prefer being kept up as high as
possible above the surface of the filtering media, in order that the water may
fall in a thin sheet or stream through the space, and I prefer the lip of the
sluice well overhanging the outside of the wall, in order that there may be a
current of air on both sides of the flowing water.
The sluices niust be formed
accordingly, and it will be easy to regulate the openings by the quantity
required. Rough shingle, or gravel, or stone, or other suitable material should
be laid on the filtering media immediately under the water falling from the
sluices, in order to break the force and prevent the disturbance of the surface
of the filtering media.
As to supplying the water to be filtered, there are two modes by which this
may be done; one by causing the raising main, or main pipe which conveys
the water from the works or main, to be connected with the trough at.
its highest point where the water will be received, and by the inclination of
the bed of the trough will be dispersed along it by gravity, and discharge
through the sluice gates on to the filtering media, and I prefer to keep a
head of water on the filtering media, from one to eight or more feet, as may be
found necessary.
Another mode by which this may be done is by continuing the raising main
along the trough formed as above described, but without paving, or openings,
or sluices, to such point as will reach all the compartments or divisions, and
from this main to have branch mains with proper sluice valves junction, so as
to deliver the water on the filtering meadia in each compartment, as may be
required; these branch mains I prefer to be perforated, and in this case it
would be necessary to build up the piers, or make some other suitable arrange,
ment for carrying or supporting these branch mains.
As to supplying the filtered water, there are two modes by which this cau
be done, one by the filtered water being received into the chamber formed in

page_text: the division walls from each compartment of the reservoir, and that chamber
being connected with the discharge well. In this well the perforated head of
the supply main or mains should be fixed, and the water thus received would
have the utmost amount of head or pressure the whole of the reservoir would
afford. In this well arrangements should be made for fixing guages to
indicate the height of the water, and similar arrangements should also be made
to shew the height of the filtered water in each of the compartments.
Another mode is by laying a draft pipe or main on the bottom or within a
few inches of the bottom of each compartment, connected by proper sluice
valves and breeches pipes with the chief supply main; and when this mode be
used the division walls may or may not be built hollow, and the discharge well
dispensed with.
As to emptying either compartment when the division walls are found
hollow, as above described, and used as filtered water chambers, this is effected
by simply closing the sluices at the side of the supply trough next to the
compartment to be emptied, and thereby prevent the further flow of water on
the top of the filtering media, and closing all the large sluices (P 4, Figure 5
& 6) connected with the filtered water chambers and the division walls,
excepting those connected with the compartment to be emptied. The draft
will remain upon that compartment, and as soon as that is emptied, which
will be indicated by the water guage, then the large sluices should be closed
and the draft supplied by the other compartments. Little experience and
attention will soon determine the best times for these purposes; being thus
emptied, the cleansing or other works may proceed as usual in such cases.
Or should the mode described for laying the draft pipes or main on the
bottom of the compartment be adopted, the method for effecting the emptying
either compartment may be simply accomplished by shutting off by means of
the sluice valve the supply to the top of the filtering media and continuing
the draft until the guage indicates the compartment is empty, and then the
shutting the sluice valve connected with the supplying main.
For cleansing the filtering media, the several processes of scraping off and
washing and relaying the sand and gravel may be adopted.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a plan of a proposed reservoir and filter bed, shewing the
compartments into which it is divided, being in this instance four, namely,
A. L, N, O. A, compartment shewing the concrete and paved flooring and

page_text: gutters are indicated by the arrows. B indicates the channels or gutters laid
to the deposit wells; C, the deposit wells covered with an hinged or moveable
iron grating; D, diagonal groining; E, side or retaining walls and piers next
embankments; F, the concrete lining of inner slope of embankment, and the
inclination of which I prefer to use is one foot vertical rise to one and a half
feet horizontal length; G, brick or stone linings on concrete of inner slope
next top of embankment to counteract the wash of the water; H, foot or cart
road on top of embankment; J, outer slope of embankment, and the in-
clination of which I prefer is one foot vertical to two feet horizontal, but
greater inclinations would answer the purpose, depending on the material
used; K, entrance shaft or man-holes, acting also as air escapes; L, com-
partment shewing the mode of constructing the archings or roofs of the filtered
water chambers and the diagonal groining D, (top or outside view); M and
M', air shaft for egress of air, and acting likewise as man-hole for repair or
cleansing the filtered water chamber, and constructed over the deposit wells;
N, compartment shewing the mode of constructing the archings in this com-
partment being (top or outside view); ×³, transverse arch to be constructed
higher than the arches N to allow means for accumulating air to escape by
the air shaft and man-holes M'; O, compartment shewing the paving channels
or gutters and deposit wells, as in compartment A, and the arrangement of the
piers to suit the arching, as shewn in compartment N, and the transverse
arch x2; P, the division walls and supply trough; R, the discharge well.
i
Figure 2, section on the line A2, A3, shewing the general arrangements of
the division walls, the filtered water chambers, the deposit wells, the air shafts
or man-holes, the filtering media, head of water on same, and embankments;
S, puddle clay gutters or banks; T, the concrete flooring or foundations, and
the paving; U, natural ground line; W, filtering media; Z, head of water;
Y, filtered water chambers. All the lettering in this Figure, which are
identical with Figure I., indicates and refers to the same objects.
.
Figure 3, enlarged plan of portion of compartment at the lower right-hand
corner of Figure 1. The letters of reference on this Figure denoting those
parts in Figure 1, referring to the same letters, indicate and refer to the
same objects.
Figure 4, enlarged section on the line A³, A', Figure 1. W¹, filtering
media; T', concrete flooring or foundations and paving; X, piers and stone
bases supporting the arched roof ✗' of filtered water chambers; Y, filtered
water chambers; E, side or retaining walls; Z, head of water on surface of
filtering media.
Figure 5, enlarged section on the line A, A, Figure I. shewing the detail

page_text: of the division wall P and supply trough; G, brick side of trough of cross
division wall; ✗, piers on stone bases, supporting the arches; Y, filtered
water chambers; Y', filtered water delivering chamber or channel; P¹, divi-
sion walls; P, strutting arches; P³, invert; P, opening and sluice from
filtered water chambers; X', archings found either with open joints on pur-
pose-made bricks; W¹, filtering media; Z', head of water or media; P³, tie
arch; P, supply trough; P', supply sluice; T¹, concrete foundation and paved
floor of filtered water chambers.
Figure 6, section on the line A7, A8, Figure 1 and Figure 5.. T¹, concrete
foundations; P³, invert to division walls; P³, strutting arches; P*, opening
and sluice from filtered water chambers; P, tie arch and paved bed of
supply trough; Po, supply trough; P7, supply or water-distributing sluice;
R³, discharge well; D³, external walls of discharge well; D³, raising main
from pumping engines; D', grating or strainer; D³, draft or supply main, with
strainer or perforated end.
When my Invention is applied to domestic or manufacturing purposes,
and where the cisterns, tanks, backs, or vats are moveable, I prefer to con-
struct them with slate; but they may be made of stone, wood, lead, iron, or
other suitable material. For the lower portion or filtered water chamber I
prefer to have an inner lining, with a space between this lining and the side of
the cistern, tank, back, or vat, the space being only of a few inches in width,
and which I prefer to be left hollow, or filled with medicum which is bad
conductor of heat, and that I prefer such lining to be of slate or other suitable
material. The height of this lining will vary according to the size of the
cistern, tank, back, or vat; I prefer it to be about half the depth of the
cistern, tank, back, or vat, and the top of this lining will form a bearer or
ledge all around the inside of the cistern. On this ledge I lay a tray formed
of slate slab or other suitable material, the bottom being drilled with holes, or
having other openings or spaces to allow of ready percolation, and I then fill
this tray with a filtering media, formed of cleaned washed gravel and sand,
carefully graduated and compressed to a compact mass. On this I lay a
cover formed of slate slab or other suitable material, drilled with holes, or
having other openings or spaces, and fastened by means of bolts or keys,
either of iron or slate, or other suitable means, to the bottom of the tray or
sides of the cistern, tank, back, or vat, or only laid on the surface of the
media, though I prefer it to be bolted through, or secured as last described.
It is not, however, necessary that the holes should be as small or in the same
parts as the bottom, the principal object of this cover being to prevent the
disturbance of the filtering media by the action of the water on the surfaco

page_text: when first let on, see Figures 7, 8, 8, 8. Pipes of iron, lead, or other
suitable material should be secured to the bottom and top of the tray to allow
for the escape of air.
Figure 7, plan of cistern, tank, back, or vat, shewing the inner lining and
air space. a, tank lining; b, space to be filled with a medicum being a bad
conductor of heat, or left hollow; c, outside of cistern; d, supporters for filter-
ing tray; e, filtered water chamber.
Figure 8 a, inner lining; b, space; d, supporters for filtering tray; e,
filtered water chambers; f, tray filled with filtering media; f, air escape
pipes; f, bolts or keys; g, water on top of filtering media. Figure 8 a, elc-
vation of cistern; f³, air escape pipes; Figure 8b, end elevation; f', air
escape pipe.
The water being delivered on the top of this tray will percolate by means
of the holes in the slate through the filtering media, and be preserved in the
filtered water chamber below ready at all times for use.
Though this description of reservoir and filter bed, and of the cistern, tank,
back, or vat, may be constructed as above described, yet I do not confine
myself to the use of the materials I have mentioned, any materials not acted
on by water, and of sufficient strength and durability, may answer the purpose;
nor do I confine myself to that particular form of reservoir and filter, or
cistern, tank, back, or vat, as shewn by the accompanying Drawings, nor to
the details as herein described, so long as the peculiar character of my
Invention be retained, as these may be varied; but in all cases it is advisable
that the should be divided into compartments to afford the means of entry to
the, as it were, subterranean filtered water chambers, if at any time it should
be required, and that these filtered water chambers should be of sufficient
height to allow of an ample storage of filtered water.
I claim as my Invention the formation of a covered storage reservoir, such
as is herein described, or similar thereto, for filtered water, by the construction
of the filtered water chambers extending over the area of the reservoir, and
the covering of this area by the filtering media, thereby forming, as it were, a
subterranean filtered water reservoir, by which means the filtered water will
be obtained and preserved in a state of coolness, great purity, and free from
contamination.
In witness whereof, I, the said Frederick Philip Thompson, have here-
unto set my hand and seal, this Second day of August, One thousand
F. P. (L.S.) THOMPSON.

page_text: AND BE IT REMEMBERED, that on the Second day of August, in the
year of our Lord 1852, the aforesaid Frederick Philip Thompson came before
our said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according
to the tenor of the Statute made for that purpose.
「
Enrolled the Second day of August, in the year of our Lord One thousand
eight hundred and fifty-two.