A NEW OR IMPROVED METHOD OF PREPARING AND BURNING CLAY, AND APPLICATION OF THE SAME IN THE MANUFACTURE OF APPARATUS AND CONTRIVANCES FOR THE PURPOSES OF ABSORBTION, OF FILTRATION, AND OF CHEMICAL DIALYSIS
Year: 1880

page_text: LETTERS PATENT to John Guy Wilson, of the Office for British & Foreign
Patents, 71, Market Street, in the City of Manchester, Mechanical Engineer
and Patent Agent, for an Invention of "A NEW OR IMPROVED METHOD OF
PREPARING AND BURNING CLAY, AND APPLICATION OF THE SAME IN THE
MANUFACTURE OF APPARATUS AND CONTRIVANCES FOR THE PURPOSES OF
ABSORBTION, OF FILTRATION, AND OF CHEMICAL DIALYSIS." A communication
from abroad by Dr. George Praetorius, of Breslau, Silesia, Kingdom of Prussia,
in the Empire of Germany,
PROVISIONAL SPECIFICATION left by the said John Guy Wilson at the
Office of the Commissioners of Patents on tho 6th April 1880.
JOHN GUY WILSON, of the Office for British & Foreign Patents, 71, Market
Street, in the City of Manchester, Mechanical Engineer and Patent Agent.
"A NEW OR IMPROVED METHOD OF PREPARING AND BURNING CLAY, AND
APPLICATION OF THE SAME IN THE MANUFACTURE OF APPARATUS AND CONTRIVANCES
FOR THE PURPOSES OF ABSORBTION, OF FILTRATION, AND OF CHEMICAL DIALYSIS."
A communication from abroad by Dr. George Praetorius, of Breslau, Silesia,
Kingdom of Prussia, in the Empire of Germany.
This Invention relates to an improved method of preparing and burning clay in
order to obtain a material which can be rendered porous or otherwise in the course
of manufacture, and to be used in the construction of various apparatus or
contrivances, say, for the purpose of filtration, for absorption, and for chemical
dialysis. The clay employed for the manufacture of absorption and other similar
vessels which are to be subjected to and capable of resisting the influence of acids,
must be free from all combination of iron and lime, but for other purposes
ordinary clay prepared in the same manner as in the manufacture of faïence may
be used.
The clay is mixed with a certain quantity of powdered wood charcoal which has
been previously subjected to the influence of muriatic acid, and kneaded together
into a homogeneous compound, out of which the desired vessels are formed or
pressed, and afterwards burned or baked, those designed for the purposes of

page_text: absorption and dialysis being burned in chills, whilst those for filtering vessels are
burned in ovens. For absorption vessels the proportion of powdered charcoal is
75 per cent., whilst for vessels used for filtration or dialysis the proportion is
33 per cent. To produce a partial glazing of these vessels, the parts which are to
remain unglazed are dipped into or are besmeared with oil or fat, or covered with
oil cloth, whilst all the other parts not so treated are rendered more or less porous
by the burning or baking operation.
The absorption vessels are unglazed except at their outer ends, and may be made
of a circular, rectangular, or other desired shape, and if of a cylindrical form they
may be arranged with conical bottoms, and with corresponding recesses in their
tops so as to fit one into the other, leaving an enclosed space between, and thus
such vessels constitute a cylinder, the outer or cylindrical surfaces of which are
glazed, and which can be closed in at both extremities by a glazed cover, and thus
present a series of enclosed absorption surfaces to the contents which are at the
same time protected by the glazed surfaces from the influence of the atmosphere.
The absorption vessels are capable of being used in place of filtering paper, and
as a substitute for the tiles or plates hitherto used for absorption purposes, and are
considerably more durable, secing that they are not affected by the destroying
influences of acute acids. Moreover vessels so constructed can be employed over
and over again continuously as soon as they are washed and purified by means of
water mixed if necessary with muriatic, sulphuric, or nitric acid, but if used for
the treatment of organic preparations, such vessels need only to be washed with
pure water and dried in the air in a warm place to render them fit for renewed
usc..
Vessels serving the purpose of chemical dialysis may consist by preference of a
cylinder or rectangular box open at the top, and glazed inside and outside and
divided internally into two compartments by a division plate formed of porously
burned clay made in accordance with this Invention, or such apparatus may
consist of two separate parts, 1st, of a cylinder, the feeding pipe of which is glazed,
whilst the other surfaces are porous, and 2nd, of a tank into which the cylinder
before mentioned is placed, such tank being constructed of any suitable water-
tight material.
In constructing filtering apparatus the necessary porous or filtering portions of
the same are constructed of clay prepared as hereinbefore described, and may
either for themselves the filtering medium, or may be used in conjunction with
charcoal, sand, or other filtering media. One modification consists of two vessels,
the upper one of which is open at the top to the atmosphere, and is formed at the
lower part of two layers of the improved porous material, the upper layer being
more porous than the lower one, and which thus constitute the filtering surfaces,
whilst the lower vessel is enclosed and made entirely of glazed earthenware or
other suitable material. These two vessels are placed the one on the top of the
other, and the necessary air-tight joint between the two is effected by preference
by an annular recess formed in the joining surfaces, and into which an india-
rubber tube is inserted, this tube being provided with a suitable stop-cock, so that
when the air is exhausted from such tube, the same becomes flattened and permits
of its easy introduction into the annular recess before mentioned, whilst the two
compartments of the filter are brought together, but which tube when the air is
once more admitted swells out, and so makes an effectual air-tight joint. Another
modification consists of a bottle or other suitably shaped vessel formed of this
improved porous material, and through the walls of which the liquid to be filtered
is drawn by a pump or other means, or slabs of this material may be used instead
of the filter cloths now employed in apparatus for filtering saccharine liquids, or
cylinders may be made of the same material and be strengthened with iron hoops,
and so be employed in centrifugal machines. Again, tubes may be formed of the
same porous material either in straight, curved, or other suitable shapes and lengths,
and be combined with pumps for filtering purposes.

page_text: This improved material may also be made as follows, and used instead of
charcoal for filtering purposes:-Sixty per cent. of charcoal powder is added to
clay, and the compound so formed is divided into small pieces, say, from / to ³/
of an inch in size; these small particles are burned and become porous by burning
out the charcoal; or instead of small pieces of the compound as aforesaid, the said
compound may be plastered on to cloth or other suitable fabric in thin layers, and
the same be rolled into cylindrical form and dried in the open air, and afterwards
burned at the highest temperature. After burning, the roll is divided into discs
by means of a saw, or crushed into pieces of the required size, and then may be
used in place of animal charcoal or for filling filters, being capable of being
renovated by reburning.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Guy Wilson in the Great Seal Patent Office on the 6th
October 1880.
JOHN GUY WILSON, of the Office for British & Foreign Patents, 71, Market
Street, in the City of Manchester, Mechanical Engineer and Patent Agent.
"A NEW OR IMPROVED METHOD OF PREPARING AND BURNING CLAY, AND
APPLICATION OF THE SAME IN THE MANUFACTURE OF APPARATUS AND CONTRIVANCES
FOR THE PURPOSES OF ABSORPTION, OF FILTRATION, AND OF CHEMICAL DIALYSIS."
A communication from abroad by Dr. George Praetorius, of Breslau, Silesia,
Kingdom of Prussia, in the Empire of Germany.
This Invention relates to an improved method of preparing and burning clay, in
order to obtain a material which can be rendered porous or otherwise in the course
of manufacture, and so be used in the construction of various apparatus or
contrivances, say, for the purpose of filtration, for absorption, and for chemical
dialysis. The clay employed for the vessels of absorption and other similar vessels
which are to be subjected to and capable of resisting the influence of acids, must
be free from all combination of iron and lime, but for other purposes ordinary
clay prepared in the same manner as in the manufacture of faience may be used.
The clay is mixed with a certain quantity of powdered wood charcoal, which has
been previously subjected to the influenco of muriatic acid, and mixed together into
a homogeneous compound, out of which the desired vessels are formed or pressed,
and afterwards burned or baked. For absorption vessels the proportion of powdered
charcoal is 75 per cent., whilst for vessels used for filtration and dialysis the pro-
portion is 33 per cent. These proportions are of the highest importance, for more
charcoal mixed with the prepared clay renders it impossible to produce practicable
vessels. In producing vessels for the purpose of absorption and of chemical dialysis,
the clay is mixed with charcoal dust, and for manufacturing filters the grain of the
charcoal may be from 1/4" to " inch diameter. As the plastic clay after the
burning out of the charcoal becomes so smooth that it can be scratched with the
nails of the hand, there is added to it about from 10 to 12% of fluor spar, and an
equal quantity of Norwegian feldspar; or pulverised quartz or kaolin may be used
for the same purpose according to the nature of the clay. The parts of the filters
which are not required to be porous are made of ordinary clay and glazed, or of a
clay of best plastic qualities, to which is added 20 or 30° of feldspar, in which latter
case glazing is not necessary. Vessels intended for the purpose of absorption and
dialysis are burned in chills in such a manner that the heating gases may reach
the objects, but that the latter are not brought directly into contact with the flame
until the disappearance of the charcoal.
The filtering vessels are burned in ovens or kilns heated by charcoal or coal fires,
and without the use of chills. In case however of the burning furnace being heated
by coal the vessels are covered after being air-dried with a compound of from 30
to 40° of charcoal dust and 60 to 70° of pulverised clay, which is mixed with
water, and after the burning operation is shaved off the vessels.
To produce a partial glazing of these vessels, those parts which are to remain
unglazed are dipped into oil, or are besmeared with oil or fat, or covered with oil-
cloth.
Vessels serving for the purpose of absorption remain unglazed, and are only
provided at their outer ends with a coating of glaze, and thus the atmosphere or
liquids employed penetrate the inside of such vessels.
Absorption Vessels.-Figs. 1 and 2 of the accompanying Drawing represent an
absorption vessel of a circular form, whilst Fig. 3 represents a similar vessel of
rectangular shape, both being of simple and practicable construction.

page_text: Figs. 4 and 5 represent vessels which can be placed one above the other, by
which means it is rendered possible to protect the substances which are to be dried
within them against the influence of the air, and yet to submit such substances to
the influence of two absorbing surfaces. The conical shape a, b, c, d, of the under
side of the vessel represented in Fig. 5, and the corresponding shape of the upper
part, effect a close joint betwixt two of such vessels when placed one upon the
other. Fig. 6 illustrates a vertical section of several of such vessels placed ono
upon the other, and thus forming a cylinder closed at both extremities, and having
the cylindrical surfaces glazed.
To obtain large surfaces for the purposes of absorption a certain number of the
vessels just described are arranged together in one frame, the material of con-
struction being chosen according to the qualities of the substances to be dried in
such vessels. The practicable dimensions of the absorption vessels are from 2', to
25 inches diameter, and 21% to 25 inches in depth or height. The manufacture of
larger vessels is discouraged, secing that they are liable to fracture and to changing
shape during the burning process.
Vessels thus constructed are a substitute for filtering paper, and for the tiles and
plates hitherto employed, and especially as they are not affected by acids. They
can be used over and over again continuously as soon as they are washed and
purified by means of water mixed, if necessary, with inuriatic, sulphuric, or nitric
acid. If such vessels have been used for the treatment of organic preparations they
require only to be washed with pure water and then dried in the air or a warm
place, and are thus rendered fit for renewed use.
Vessels serving the purpose of chemical dialysis.-The first category of vessels for
this purpose consist of a cylinder or a rectangular box open at its upper end and
glazed inside and out, divided internally into two compartments by a division wall,
consisting of porously burned clay. Each compartment is provided with a stop-
cock. The other category consists of vessels formed in two separate parts, 1, in a
cylindrical vessel, the feeding pipe of which is glazed, whilst the other surfaces aro
porous and unglazed; 2, in a tank into which the first vessel is placed, this tank
being provided with an outlet pipe, and constructed of any water-tight material.
Filtering Apparatus.-This consists principally of a vessel constructed of porously
burned clay made in accordance with this Invention, and which, in certain parts of
its surface, is made impermeable by means of glazing; and of a second vessel serving
to receive the filtered liquid. Or there may be employed a vessel of large surface
(formed entirely of porous clay without any glazing), which is immersed into the
liquid to be filtered. This filtering vessel may be combined with another vessel
from which the air is exhausted.
The filtering apparatus can also be divided into two compartments, and in this
case a porously burned plate is placed upon an annular projection within a vessel
formed of any impermeable material, and a perforated plate of glazed earthen waro
can be placed in certain cases under the above mentioned filtering plate; or such
perforated plate may be formed of metal. From the lower compartment the air is
exhausted by means of an air-pump.
I will now proceed to describe the different modifications of improved filtering
apparatus constructed in accordance with this Invention, and illustrated on the
annexed Drawings.
Figs. 7 and represent a combined filtering apparatus with provision for the
exhaustion of air. This apparatus consists of two vessels B and C, the lower
extremity of the vessel B being placed within and fitting the upper part of the
vessel C.
The upper vessel B is provided with handles H, whilst the upper edge of the
vessel C is arranged with a short branch pipe R and stop cock S. A hollow ring
of india-rubber K, placed within the annular groove g, h, i, k, is provided, with the
small tube passing through the branch pipe R, and which is turned up round its
flange, as illustrated. A small glass or metal pipe is inserted into this hose or tube.
The air being exhausted from the india-rubber ring K, such ring becomes flattened,

page_text: and the stop-cock S is closed. In this state the vessel B is placed within the conical
border C, and the cock S being then re-opened the air re-enters, and by distending
the ring R so produces a perfectly air-tight joint between the vessels. E, E', is a
suction pipe having its outlet end D provided with a draw off cock G, and H', H',
are handles. The pipe serving for the withdrawal of the filtered liquid is provided
with the branch J, in which is fixed the vertical glass pipe 7 communicating with
the interior of the vessel C, and which allows the level of the filtered liquid to be
seen from the outside. If the vessel C is constructed of glass the gauge tubo ris
then dispensed with. The vessel C stands upon a pedestal E. The bottom of the
vessel B is formed of two layers S and S', the upper one being more porous than
the lower one, corresponding to the grain of charcoal powder employed in its
production. The annular part marked u of the vessel B consists of clay mixed
with pulverized glazing before being burned, and has for its object to prevent the
absorption of the liquid by the upper part of the filtering vessel. The glass pipe E¹
forming a bend, as illustrated, so arranged that its mouth is placed on a level
with the upper end of the glass observation pipe 7. The capacity of the vessol B
is nearly equal to one third that of the lower vessel C.
Figures and 10 represent a filtering apparatus suitable for use upon the tablo
of an air-pump. The suction pipe E is fixed within the centre of the spherically
shaped bottom of the vessel C, this cylinder C being provided with two observation
glasses F, F, which are superfluous if such vessel is constructed of glass. L is the
stop-cock appertaining to the suction pipe of the air-pump. The two receptacles B
and C are provided with the annular grooves fand f', in which the india-rubber
ring r fits closely, so forming an air-tight joint owing to its elasticity, and which is
compressed by the copper or iron band R (sco Fig. 13).
Figure 15 shews a section of a filtering apparatus shaped like a filter-bag, which
is fixed air-tight over the filtered liquid vessel. This apparatus is only glazed in its
upper part above the level of a, a, or this upper part is formed of very impermeable
clay.
Fig. 16 represents a section of a bottle-shaped filter. The bottle A is placed in:
the vessel B, which is formed with an annular projection C. The bottle A is
provided with several feet so that it stands clear of the vessel B, as illustrated. The
inouth O is closed by an india-rubber cork or stopper, through the centre of which
a suction-pipe passes, and which is fitted with the stop-cock N. E is another mouth
or branch, through which passes the syphon-pipe H, in order to empty the filtered
liquid which has penetrated through into A. The vessel B is filled with the liquid
or compound requiring to be filtered; the blocks P, P, serve to adjust the position
of the bottle A; G, G, are the handles.
Filtering apparatus employed in sugar refineries for filtering the juice by means
of animal charcoal is modified in accordance with this Invention. Instead of the
usual filter cloth or felt a plate of this improved porously burnt clay P, see Fig. 11,
is placed over each of the perforated copper plates S, so dividing the filter into two
compartiments A and B. These copper plates are supported by annular projections
in the interior of the vessel, and between such plates a perforated india-rubber disc
is inserted to ensure a tight joint all round the edges. The upper compartment A
is filled with coarso grained charcoal, and the lower one with finer grained charcoal.
The man-holes O and 0¹ serve for the withdrawal of the charcoal. This filter is
placed in communication by means of a pipe with a receiver, from out of which the
filtered liquid or juico is forced by means of an ordinary pump. If the filtering
apparatus is itself constructed of porously burned clay, and is made strong enough
by the application of suitable iron-hoops, this filtering apparatus may take the
place of the metal sieves hitherto employed in centrifugal machines. If it be
required to filter by means of charcoal in this description of centrifugal inachino
the charcoal is put into the drum whilst it is revolving in such a manner that the
inner surface of the drum becomes covered with such charcoal, after which the
liquid is introduced by means of a pipe, the mouth of which is directed against
the vertical shaft of the drum.

page_text: Figure 12 represents such an apparatus consisting of the filter A provided with
a neck R and flange E. The tank B is constructed of stone, wood, iron, copper, or
any other suitable material. The cross-piece K carries the pump P. The flanges G
and E are jointed in the same manner as described in Figure 10.
In the case of
under-ground water requiring to be filtered this filter is placed in the water or in
a well, and in this latter case the water can be submitted to different stages of
filtration by covering the filter with charcoal and with gravel, or other suitable
filtering material. This description of filter pit or well will be useful in producing
a good potable water in military encampments for the purpose of producing a very
large filtering surface, and in place of the porous and unglazed cylindrical vessel a
system of porously burnt clay tubes may be employed which may be arranged one
beneath the other, or one over the other, and combined by suitable sockets. This
system of straight or curved tubes may be also combined with pumps for the
purpose of withdrawing filtered liquid. Fig. 17 shews such a combination. R, R,
are the porous filter tubes, the middle one of which is provided with the branches B.
To the vertical branches B the boxes of cast iron A are connected in the manner
hereinbefore described with india rings, and the boxes themselves are con-
nected in the ordinary manner with the pumps P supported by the pillars S.
Z, Z, Z, are bracing bands which increase the rigidity of the construction; L, L, are
walls between which the filtering tubes R are arranged; v, v, v, v, are four
connecting tubes located between the three pairs of tubes, and consisting of less
porous material. Fig. 18 shows a similar coiled arrangement of filter, which is
also combined with two pumps. For the purpose of cleaning the deposit off the
filtering surfaces they are covered with a felted or linen cloth. Before use all tho
herein before described filters must be put into water for half an hour. For the
purpose of extracting liquids from more solid substances, and for rapidly drying
such substances the apparatus represented by Fig. 14 is employed. The cast-iron
cylinder A is provided with the piston R, and the piston itself with the stopper Z,
to fill the substance to be extracted into the space between the piston and the
bottom of the cylinder. The bottom of the cylinder consists of the perforated
metal cap e covered with a disc of india-rubber provided with corresponding
perforations. Over the metal and the india rubber cap is placed a cap of porously
burned clay p. The man hole O serves for the withdrawing of the compressed
substances. The piston rod S is hollow, and provided with the air channel i. i, i,
are guide pieces secured to the piston serving to guide the valve d up and down.
The spiral springs f, f, serve to keep the valve d away from the piston, and thus the
space below the piston communicates by means of the air channel with the
atmosphere. During the descent of the piston these springs are compressed, so
closing the air channel, which becomes opened during the ascent of the piston,
and thus only the weight of the piston has to be raised.
The improved porously burned clay can also be employed for filtration purposes
in the following manner:-To the clay is added 60 per cent. of charcoal powder,
and this compound is formed and divided into small pieces of 1/, to 3/8 inch diameter
by means of any known and suitable machinery. These small particles are burned
so that they become porous by the out burning of the charcoal, and may be placed
either round the outside of the filtering-vessels or in the interior of them. Another-
method of preparing these small filtration pieces, which on account of the capillary
attraction of their surfaces purify liquids, is as follows:-The compound of clay
and 60 per cent. of charcoal powder is plastered to a piece of textile material in the
form of a thin layer. The material so coated is then rolled up and dried in the air,
and afterwards burned at the highest temperature. After burning, the roll is
divided into squares by means of a saw, or may be crushed into small pieces and so
employed as a filtering medium or as a substitute for animal charcoal. They are
capable of being reburned after use, and this may be used over and over again.
Fig. 19 represents a modification of Figs. 12 and 16, and Fig. 20 is a sectional
view of a funnel or hopper B, in which is inserted a porous inner shell A, and

page_text: is thus useful for filtration purposes, the same acting either by percolation or
suction.
Having thus particularly described the nature of the said Invention so communi-
cated to me from abroad as aforesaid, together with the best methods with which
I am acquainted for carrying the same into practical effect, I wish it to be under-
stood that I do not confine myself to the precise details, relative proportions, or
dimensions of the various apparatus herein before described and illustrated on the
accompanying Drawings, as the same may be considerably varied without departing
from the Invention, but what I claim is-1st. The improved method of preparing
and burning clay, substantially as and for the purposes herein before described.
2nd. The use and application of the specially prepared porous clay in the manu-
facture of apparatus for the purposes of absorption, filtration, and chemical dialysis,
substantially as herein before described and illustrated on the accompanying
Drawings. 3rd. The improved arrangement and construction of apparatus for
absorption, filtration, and chemical dialysis, as herein before described and illus-
trated on the accompanying Drawing.
In witness whereof, I, the said John Guy Wilson, have hereunto set my
hand and seal, this 5th day of October, in the year of our Lord 1880.
JOHN C. WILSON