IMPROVEMENTS IN APPARATUSES FOR CLARIFYING AND PURIFYING WATER AND OTHER LIQUIDS
Year: 1860

page_text: LETTERS PATENT to Benjamin Nadault de Buffon, of No. 28, Rue
des Saints Pères, in the Empire of France, for the Invention of "IMPROVE-
COMPLETE SPECIFICATION filed by the said Benjanin Nadault de Buffon
at the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 31st December 1860, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BENJAMIN
NADAULT DE BUFFON, of No. 28, Rue des Saints Pères, Paris, in the Empire
of France, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
APPARATUSES FOR CLARIFYING AND PURIFYING WATER AND OTHER LIQUIDS," and
have petitioned Her Majesty to grant unto me, my executors, administrators..
and assigns, Her Royal Letters Patent for the same, and have made solemn.
Declaration that I am the true and first Inventor thereof.
NOW KNOW YE, that I, the said Benjamin Nadault de Buffon, do hereby
declare the following Complete Specification, under my hand and seal, fully,
describes and ascertains the nature of the said Invention, and the manner
in which the same is to be performed (reference being had to the accoin-
panying Drawings), that is to say.

page_text: The present Invention consists in certain improvements in apparatuses for
filtering water and other liquids.
The chief characteristics of the improved apparatus are, 1st., being formed
of a concentric tube and cylinder, both made of perforated and inoxidable
sheets of metal, and 2nd, containing in the space between the two cylinders
an elastic and compressible filtering matter of such a kind that by compressing
it in a press a matter having a greater or lesser degree of porosity is obtained
according to the nature of the liquid to be clarified, and the pressure under
which the flowing takes place.
Fig. 1 represents a small filter after this system, the lower extremity being
screwed to the bottom of a cask or other receptacle containing the water
to be clarified. The extremity of the upper tube is closed by a cork, the
purified water flowing off at the lower part. It will be seen on referring
to the transverse section represented, Fig. 2, that from the converging of
the streams of liquids, the latter traverses the filtering matter from the out-
side to the inside, and tends to condense and keep it together, and consequently
the filtration is performed under favourable conditions; whilst if performed
the other way-the-result-is-very-different,_as_the_filtering matter then has
a tendency to separate & become more porous, thereby allowing the liquid
to pass without clarifying it.. These two different aptitudes of the same
apparatus, according as it works alternately by one or the other surface,
are utilised by devoting the convex surface to the filtering, and the concave
one to the cleansing, which is the necessary consequence of the first operation.
The proper working of the apparatus, principally from the prompt and
efficient action of the cleansing, results from three causes, viz.; 1st., its
concentric form; 2nd, the selection of a compressible filtering matter; and
3rd, the increase of speed in an interior counter current capable of quickly
clearing the filter, as soon as it begins to be obstructed. The best substance
to be employed as filtering matter is wool shearings, resulting from the
manufacture of shawls, cloths, and other woollen stuffs; but as this is an
animal substance, and consequently very liable to decay, it can only be employed
after certain preparations to prevent it from corrupting. This preparatory
process, which consists in mineralising the wool, is conducted as follows:-
The wool shearings when they leave the manufacturies are impregnated
with vegetable colours which would give the water a bad colour, and also
frequently contain oil or other similar matters employed for greasing the
machines. These foreign matters may be removed by simply washing the
wool in a liquid containing a suitable proportion of some alkali. One of the
simplest methods is to employ a liquid formed of about 2lbs. of crystallised

page_text: soda (or a similar proportion of potash or other similar substance) to 12
gallons of river water. This liquid maintained at a temperature of about
80° centi. cleanses the wool in a few hours of the fatty matters it may
contain as well as the colouring matters.
This preliminary operation being completed, a more important one remains,
viz. the mineralisation of the wool, by means of which the latter is rendered
permanently secure against decomposition. The substance which has the
property of producing this result is tannin or tannic acid. When the wool
has been subjected to the action of tannin it becomes greatly changed by a
powerful chemical reaction and becomes incorruptible; but as this direct
action has the inconvenience of leaving a disagreeable taste, and might only
operate for a limited period, it is found advantageous to render it more.
powerful by adding an insoluble metallic salt, which becomes absorbed in
the filaments of the wool. The most remarkable of the agents effecting
this is tannate of copper, which is obtained by the reaction of tannin on
sulphate of copper, or by the direct combination of this acid with copper
filings. Tannate of iron acts in nearly the same manner, but its action is
less energetic and probably less durable. Either of these acids may, however
be employed, although the tannate of copper.appears preferable for the reasons
above stated.
The operation itself is very simple. When the wool to be employed as
filtering matter has been washed, and while still damp, it is steeped in a
solution of tannin, composed of about 2lbs. of fresh tannin to about 4 gallons
of river water. A solution of sulphate of copper is added, consisting of about
7 oz. avdp. of the sulphate to about 2 gallons of water. This is mixed withi
care and left at a temperature of 60° to 80° centi. for at least 5 or 6 hours,
at the end of which period the wool is completely incorruptible, no matter
with what liquid it is brought into contact, or at what temperature the latter
may be.
If sulphate of iron is used to produce a similar reaction about
10 oz. should be employed with the above-named quantity of water. On
leaving the vats or boilers in which the preparation is made the wool is
stretched on frames covered with canvas, where it dries. It is then well
washed in common sieves or in bags made of some permeable material, after
which it is ready to be employed with the aid of a press and stampers for
filling the filters, in which it receives the desired degree of compression.
The tannates of copper and iron being perfectly insoluble salts exercise
no injurious action on the quality of the water, as experience has satisfactorily
shown. The proportions above indicated are those usually employed, but in
some cases it may be found advantageous to vary them.

page_text: DIFFERENT FORMS OF THE APPARATUSES..
The apparatus of which the principles have been described, is divided into
three distinct classes, according to the various degrees of pressure of the
water to be filtered, and the circumstances on which the manner of the
flowing and cleansing depends. The first class (class A), represented in the
Drawings, Fig. 3, 4, 5, 6, & 7, includes the employment of a small filter
(Fig. 1) screwed to the bottom of an open vat of wood or metal, and working
under a slight pressure, not usually exceeding about 40 inches above the
bottom of the receiver.
The second class (class B) shown Figs. 8, 9, 10, & 11, consists of appa-
ratuses, which by means of a fixed or flexible tube are put in communication.
with one or more pumps, and thus furnish clarified water under a constant
pressure sensibly equal to that of the atmosphere. The apparatuses represented
Figs. 8 & 9, are portable, and that in Fig. 11 fixed, differing only in the
use to which they are are put and not in principle. The case in which the
filtration is operated by means of a siphon may also be included under this
head, the only difference being in the mode of effecting a vacuum in the
-tube-furnishing-the-clarified water. _
The third class (class C), represented Figs. 12 & 13, consists of the
filters which are placed in closed vats and put in communication with an
upper reservoir.
For these three classes of apparatus several cylinders may be placed in
the same vat, or several feeding tubes may be employed according as desired;
the system however is still the same.
Fig. 7 represents the vertical section of a metal vat, enclosing two or four
small filters screwed.to the bottom, beneath which knee pipes, suitably placed,
unite the produce of the filtration in a single stream. A similar arrangement
may be advantageously employed in filtering wines and oils.
CLEANSING THE FILTERS.
The thorough efficacy of the mode of cleansing in the present Invention
results, as has been already stated, from two causes, viz., 1st, the concentric
cylindrical form, the advantages of which have been explained; and, 2nd,
the elasticity of the filtering matter, rendering it capable of receiving the
action of a rapid current without becoming loosened or expanded. It remains
to be shown, that in all the various forms of apparatuses above described these
essential principles are strictly observed.
In the apparatus represented, Fig. 3, the filter (which is of ordinary dimen-

page_text: sions) gives rather more than one gallon per minute. The small pump
serving to cleanse it therefore furnishes a powerful stream, the produce of
which being 176 pints per second is equal to 10 times the rate of the
filtering. In the other Figures representing filters of the same class the
cleansing is effected by an injection produced by means of an upper reservoir.
Thus by raising the reservoir, or by a suitable enlargement of the branch pipes,
the injection may always be rendered as powerful as required.
For the second class (that of sucking cylinders) the same pump could not
be used for both cleansing and filtering without some modification. It is
therefore necessary to adopt one of the three following methods:-1st, to have
at the mouth of the pump a false orifice or adjutage, which reduces its
natural yield to about one-third, and use it in that condition for the filtering,
restoring it to its original state when required for the cleansing; 2nd, to
connect the filter for the latter operation with a stronger pump; 3rd, to
employ a system of flexible tubes or hose filled with water in any way, having
at the bottom a stop-cock to be opened more or less quickly in order to
produce the force required in the cleansing. Fig. 10 shows this arrangement,
which becomes indispensable, when the only pump available is the small
portable one annexed to the filter for country use.
When the sucking filter is used on board ship, and in some other instances
the mode of cleansing represented, Fig. 10, may always be employed; but as,
under ordinary circumstances, this method would offer some difficulty, the
system shown, Fig. 10bis, may be adopted instead. This system is based on
the principle of the condensed air manometer.
The receiver G, G, while empty is screwed to the filter, and on filling it
with water by means of the small pump P, the air contained in the receiver is
condensed into the upper part b, where it acts as a spring, exercising on the
liquid a, the degree of pressure desired, and on turning the cock e, the water
enters the interior of the filter with the speed and volume necessary to effect
an instantaneous cleansing.
The cleansing of the filters in closed vats (3rd class) represented Figs. 12
& 13, is effected by means of separate tubes and cocks. By having them of
a greater diameter than those employed in the filtering, the desired result is
obtained.
DESCRIPTION OF THE DRAWINGS.-CLASS A.
Fig. 1, tubular fiter of the smallest size made of galvanised perforated
sheet iron the inner tube of the same materiala handle of calvanised
Tig. 1,
Smanest Size made
garvamise
perforated
sheet iron the inner tube of the same material: a b handle of galvanised
sheet iron closed with a cork; c, small nut screw for screwing the filter.

page_text: Fig. 2, transverse section of the half of a filter, showing the convergence or
divergence of the streams of liquid, according as the flowing is from the
outside to the inside, or vice versa.
Fig. 3, longitudinal section of an ordinary cask, to the bottom of which is
screwed a small filter pouring the clarified water beneath by means of a
The pure water runs off by the cock e and the water employed in the
cleansing by a valve.
cock o.
Fig. 4, the same description of filter screwed to the bottom of a vat of
sheet iron, at the bottom of which is fixed a horizontal tube b, c, communi-
cating with a vertical pipe c, d, in which is placed at will another similar pipe,
in which again a funnel h is placed. In this manner the funnel and tubes,
being together about 7 feet high, will contain about 1 gallons of water, and
on turning the cock when the vat is empty, or nearly so, the water contained
in the tubes is precipitated by its own weight into the interior of the filter,
thereby effecting the cleansing. The object of this arrangement, which is less
efficacious than the first, is to avoid the use of a pump.
Fig. 5, arrangement applicable when the above-mentioned filter is employed
where the water is laid on, running very slowly by a guaged orifice requiring
the-employment of a reservoir. The reservoir is supposed to be placed at a
height of 7 to 12 feet above the level of the filtering apparatus; the
fresh water then descends from the reservoir in the vertical pipe separated by
a cock from the horizontal tube placed under the vat, as in the preceding
case. The cock supplying fresh water is soldered on a small circular box.
The cleansing is effected by means of a stop-cock after the partial or total
emptying of the vat; n, cock for the clarified water. A small valve is arranged
for the passage of the dirty water caused by the washing.
Fig. 6, same filter and vat arranged as required when the fresh water is
received from a pipe r, s, coming from the supply; s, cock for the fresh
water; r, ditto for the cleansing. If the cocks r, s, are exposed to shocks.
from the shutting off of the water from without, they may be protected by
adding a small cone pierced with holes, as represented u in the same Figure.
Fig. 7. In case the supply of water takes place but once a day by means
of an orifice closed by a turn-cock opening in a public road, the advantage of
a spontaneous cleansing by a counter current may still be retained by adapting
the horizontal tube already described beneath the reservoir (which may be
either of sheet iron or wood) receiving the proper volume of water, and by
making the same arrangements as in the preceding case. To cause the water
at the moment of the distribution to penetrate in a suitable proportion into
the interior of the filter, the orifice of the discharging pipe is furnished with a

page_text: Fig. 13, slightly different arrangement of the mechanism of a larger
apparatus of the same class. The direction of the arrows indicate the working
of the cocks both for the filtering and cleansing.
From the above description, it will be seen that the filters are composed of
two concentric cylinders of inoxidable perforated sheet iron, the space between
them being filled with a single layer of wool shearings prepared in the manner
above described, and condensed in a press, although, if thought proper, other
matters may be employed. The distinguishing characteristic of the filters is,
that they are completely immersed in the liquid to be operated upon, and
effect the filtering from the outside to the inside, whilst the cleansing is
operated in the reverse manner by means of a counter current from the interior
to the exterior. The efficacy of this plan results from the employment of a
compressed elastic substance, and the greater degree of speed given to the
counter current.
The layer of filtering matter may be either homogeneous or mixed, that is
to say, it may be of wool shearings only, or of wool mixed with other sub-
stances, such as cotton, hemp, flax, &c., which have previously been subjected
to the mineralising process above described. The prepared wool may also be
used in conjunction with a small quantity of fine powdered matter such as
charcoal without changing the system above described, provided the mixture
preserves a certain degree of elasticity.
Having thus described my Invention, and the manner in which the same
may be carried into effect, what I claim and desire to secure by Letters
Patent is, the improvements in tubular filters above described and represented
in the accompanying Drawings, the details of which, however, may be varied
without departing from the principle on which the Invention rests.
I also claim the mode of preparing the wool and other matters for the pur-
poses above described.
In witness whereof, I, the said Benjamin Nadault de Buffon, have
hereunto set my hand & seal, this Thirty-first day of December, in
the year of our Lord One thousand eight hundred and sixty.
BENJAMIN NADAULI DE BUFFON.
(L.8.)