IMPROVE- MENTS IN MEMBRANES OR MEDIA FOR ELIMINATING MICRO-ORGANISMS FROM LIQUIDS AND GASES AND IN THE METHOD OF AND APPARATUS FOR THE MANUFACTURE OF SUCH MEMBRANES OR MEDIA
Year: 1883

page_text: LETTERS PATENT to Charles Denton Abel of N° 28 Southampton Buildings
Chancery Lane in the County of Middlesex for an Invention of "IMPROVE-
MENTS IN MEMBRANES OR MEDIA FOR ELIMINATING MICRO-ORGANISMS FROM
LIQUIDS AND GASES AND IN THE METHOD OF AND APPARATUS FOR THE
MANUFACTURE OF SUCH MEMBRANES OR MEDIA "
communicated to him from
abroad by Friederich Breyer of Vienna in the Empire of Austria
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 24th April 1883.
.
CHARLES DENTON ABEL of N° 28 Southampton Buildings Chancery Lane in
the County of Middlesex "IMPROVEMENTS IN MEMBRANES OR MEDIA FOR
ELIMINATING MICRO-ORGANISMS FROM LIQUIDS AND GASES AND IN THE METHOD
OF AND APPARATUS FOR THE MANUFACTURE OF SUCH MEMBRANES OR MEDIA "
[communicated to him from abroad by Friederich Breyer of Vienna in the Empire
of Austria]
This invention relates to the production of a medium by means of which it is
rendered possible to eliminate from liquids and gases all known micro-organisms,
and probably all such that are in existence.
The medium consists essentially of exceedingly finely divided microliths, for
which a specially prepared metallic gauze serves as support.
The mode of producing this medium, as also the apparatus required for this
purpose, and the mode of using the same will be readily understood from the
following description.
If microliths, preferably microliths of talc, such as are known in trade as stick
asbestos, asbestos fibre, or Bostonite, are reduced under water, small fibres are
obtained that are finer than cocoon silk or spiders' web and not thicker than from
0.000012 to 0.000051 (0.0003 to 0-0013/m) but which are from 10,000 to
100,000 times as long as they are thick.
The splitting of the stick asbestos into its finest particles is best effected by

page_text: means of a roller mill whose rolls have only a rolling motion and no, (or very
Blight) sliding or grinding action, and which work under water and exert a pressure
of at most 11 lbs (0.5 kilogrms) per 0.16 square ins. (1 square cent/m) of roller
surface. The splitting of the Bostonite is best effected by a so-called whole-stuff
rag engine such as is used in paper making, the roller blades of which may approach
the fixed blades to within a distance of 00197 ins. (0.5™/m).
The asbestos thus prepared is separated by deposit in apparatus consisting of a
vertical drum with a stirring apparatus, the axis of which is tubular at the lower
end and is provided with two or more series of holes at different levels. A discharge
pipe with cock is made vertically adjustable in this axis.
This apparatus is charged with asbestos from the rag engine or roller mill to such
an extent that the weight of the water therein is from 1000 to 2000 times that of
the weight of the dry asbestos.
The stirring apparatus is then rotated (about from 30 to 60 revolutions per
minute) and according as the asbestos is to be sorted into a greater or less number
of degrees of fineness, it is allowed to subside for from 15 to 30 minutes. In order
to withdraw the finest particles first, the discharge pipe is so adjusted that the
liquid with the suspended microliths can only flow off through the uppermost holes,
the cock being opened. On then closing the cock the pipe is adjusted with its
upper opening level with the next holes and the cock being opened again the liquid
is drawn off in a separate receptacle. The remainder being then drawn off through
the lowermost holes, this is again subjected to reduction.
Thus by the system of reduction employed and by means of the adjustable
discharge tube in combination with the said apertures of different levels the size of
the asbestos particles can be regulated according to the density and fineness of the
micromembrane required.
"
The fibrous material thus obtained can however not be employed directly for
the purpose in question. It must be attached to a support for which purpose,
metallic wire gauze is best suited, which is prepared and mounted as follows:-
A wire gauze of about 0.0078ins (0.2/m) linear opening in the mesh and about
0.00355 (0.09m/m) thickness of wire is stretched either over a metal frame or
on a metal grating. These frames or gratings may be square, round, oval or other
shape. The wire gauze is stretched by placing the frame on a fixed base and, after
laying the wire gauze upon it, pressing a second metal frame provided with leather
packing down upon it so as to clamp the gauze between the two frames whereby
the wire gauze will be stretched perfectly smooth. A third frame is then fixed
permanently thereon, after which the clamping frame is removed.
For stretching wire gauze over the metal grating the former is first stretched flat
in another frame, and is then placed with the frame on the grating, whereupon the
frame is secured to the grating by rivets or otherwise, so that the wire gauze
becomes stretched to the required degree. Two gratings thus prepared are then
placed with the wire gauze surfaces facing each other and are screwed together, a
vulcanite or gutta percha plate having been first placed between the wire gauze
surfaces.
In this condition the metal gratings or frames are placed in an electro-plating
bath and are allowed to remain until the wire gauze has become stiffened by the
metallic electro-deposit at the point of interlacing of the wires, and the wire gauze
is also in metallic connection with the metal frames or gratings. The gratings are
then separated from each other and each grating is separately treated in the bath
again in order to obtain a uniform deposit. By this means a porous homogeneous
metal plate which forms the bed of the micromembrane is obtained. Upon this bed,
the above described fine fibre material is deposited by subsidence and is connected
thereto in the following manner.
The metallic bed is placed with the wire gauze uppermost in a sediment frame,
the upper edge of which must be at least 0.196ins (5 m/m) above the top of the
membrane bed, and the bottom of which must have an opening, which is just as
large as the wire gauze surface above it.

page_text: This frame rests with feet loosely upon the bottom of a sediment vessel, and has
a fixed solid partition below it which only serve to prevent the formation of eddies
above the discharge pipes in the bottom of the vessel when letting off the sediment
liquid. After the membrane bed has been placed in the sediment frame and this
has been placed in the vessel a stirring apparatus is lowered in the latter to such
an extent that a horizontal perforated pipe thereof is situated from 0·6 (15°/m)
to 0.98 (25%) from the membrane bed; a liquid consisting of one part by weight
of a solution of soda or potash-water glass of 1-25 to 1.30 specific gravity with 100
parts by weight of water is poured in a boiling condition through a pipe so as to
stand above the sediment frame and to drive all air bubbles completely out of the
membrane, whereupon the sediment vessel is filled with the same liquid mixture
in a cold condition up to above the perforated pipe.
The asbestos particles, or generally, the mass of microliths to be employed for
the micromembrane is introduced into the stirring apparatus together with a
mixture of water-glass and water, in such proportion that on discharging the
whole contents of the stirring apparatus into the sediment vessel by opening a
cock, 3000 to 4000 parts of liquid having 5 per cent water glass of 1.25 to 1.30
specific gravity are made to contain 1 part of dry microliths. Before opening the
cock stirrers in the stirring chamber are rotated for at most 1 to 1 minutes at a
speed of about 30 revolutions per minute.
After the stirrers have stopped the cock is opened and the mass is allowed to
flow through the perforated pipe into the sediment vessel, care being taken that no
frothing or formation of air bubbles in the liquid takes place, and that the
sediment vessel is supplied as uniformly as possible. The stirring apparatus is
now taken out and the sediment vessel is covered by a plate and put by to rest,
so as to allow the suspended microliths to deposit on the wire gauze in the form
of a thin loose snow like layer. After the deposit has been effected the cock of
the discharge pipe, whose restricted opening extends to just under the before
mentioned partition plate is opened.
The discharge of the liquid must not take place with shocks, and generally
speaking it must only be effected at such a speed as though the whole of the liquid
had to pass through the layer of microliths. Several sediment frames may be
arranged side by side in one sediment vessel."
On the completion of the depositing process the whole sediment frame inclusive
of the micromembrane formed and the metal bed is placed in a drying stove and
dried at a gradually increasing temperature rising to from 212° to 248° Fahr.,
until a uniform white shining surface is observable. By this drying process a
peculiar change is effected in the loose fibres and microliths lying upon the metal
gauze owing to their applying themselves closer to the surface thereof. The thin
films of water glass solution which connect the microliths with each other, tear by
the drying, and form inorganic connections between the microliths. After cooling
the micromembrane together with the metal bed, these, together with the sediment
frame, are placed in a vessel constructed just the same as the before mentioned
sediment vessel. Several sediment frames with dried micromembranes can be.
placed in this vessel if metal gratings are placed upon them to support the feet of
the superposed frames.
After the dried micromembranes are placed in the vessel, a solution consisting
by preference of three parts by weight of calcic chloride to 100 parts of water are
poured into the vessel just as slowly as it was previously drawn off. Instead of
calcic chloride, chloride of magnesium or chloride of barium can be employed.
The membranes are left in this bath for from 4 to 6 hours, and during this time
microscopically observable change also takes place which is of the greatest
mportance.
The before mentioned films of water glass dissolve somewhat, and roll up into
exceedingly small globules and attach themselves under occlusion of common salt,
n the form of micro-crystals of silicate of lime, barium, or magnesia to the
nicroliths, so as to serve as an inorganic connection to these.

page_text: After fixing by means of the chloride of calcium bath the liquid is allowed
to flow off slowly through the discharge pipe and the micromembrane is placed,
without the sediment frame, in a vertical position in pure water in order to remove
the soluble salts from the micromembrane.
If it is desired to obtain very fine and dense micromembranes, the same
depositing and cementing processes as above described may be repeated once or
twice on the same membrane, the finer and the finest microliths being successively
deposited, and by this means it is possible to obtain an inorganic membrane which
at about 0.01 (0.25 m/m) to 0·012 (0.30m/m) thickness has on the outer layer
of 0-002 (0-005/m) thickness for every 0·0015 sq ins (1 square "/m) from
that in
three hundred thousand to four hundred thousand microapertures, so
.consequence of. the fineness of the microliths and diffused position thereof, about
one third of the membrane surface may be considered as open surface, thus offering
to the passage of liquids or gases, on account of the great thinness of the membrane,
no other resistance than the coefficient of friction of fibrous bodies.
It should be stated that about from 0.11 grains to 0.15 grains (7.5 to 10 milli-
gramme) dry asbestos fibre are required for every 0·0015 sq ins (1 sq "/m) of
membrane surface of a thickness of from 0.001 to 0.012. In order to obtain
so called micro membrane
greater durability two micromembrane plates or
elements are connected together with their membrane surfaces facing each other,
the edges of the frames being cemented together watertight by means of india
rubber. solution. Such a combination is termed a membrane system and it can be
used in any desired position for eliminating the microbodies and micro-organisms
from liquids and gases. It acts both as bottom plate, as cover, and as side wall for
eliminating chambers whether the liquid or gas passes from the interior to the
outside or conversely.
With reference to the construction of apparatus, for instance, for the elimination
of microbodies and microorganisms from air for ventilation and from impure
water that requires to be rendered potable, the apparatus consists by preference of
two opposite membrane systems connected at their rims, and having a siphon
connected to the space between them. If this apparatus is placed in a reservoir
and the air is exhausted from the siphon, the liquid to be freed from microbodies
and micro-organisms flows through the micro membrane system into the central
space and flows off at the lower end of the siphon with a very small difference of
'levels.
This apparatus, which is particularly suitable for portable purposes, is provided
with a casing of stamped sheet steel provided with suction apertures. The size of
the siphon pipe should be so calculated as only to pass as much water as can be
yielded by the entire micromenbrane surface.
These double membrane systems may be used in any size, both as apparatus for
travellers, troops, & and for the supply of water to towns &°.
When the outer surface of the membrane has become coated with impurities
through use, it can be cleaned by sluicing, or, for small apparatus, by lightly
brushing with a feather brush. If the apparatus has become quite unusable, the
parts of the micro-membranes consisting of the microliths can be removed and
replaced by new ones, while the metallic portions can be re-used repeatedly by
slightly electro-plating them again.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Denton Abel in the Great Seal Patent Office on the
23rd October 1883.
CHARLES DENTON ABEL of No. 28 Southampton Buildings, Chancery Lane, in
the county of Middlesex IMPROVEMENTS IN MEMBRANES OR MEDIA FOR
ELIMINATING MICRO-ORGANISMS FROM LIQUIDS AND GASES AND IN THE METHOD
OF AND APPARATUS FOR THE MANUFACTURE OF SUCH MEMBRANES OR MEDIA "
A communication to me from abroad by Friederich Breyer of Vienna in the Empire
of Austria
-
This invention relates to the production of a medium by means of which it is
rendered possible to eliminate from liquids and gases all micro-organisms known
until now and probably all such that are in existence.'
The medium consists essentially of exceedingly finely divided microliths, for
which a specially prepared metallic gauze serves as support. The mode of
producing this medium, as also the apparatus required for this purpose and the
mode of using the same will be readily understood from the following description,
referring to the accompanying drawings.
Fig. 1 shows a vertical section of the apparatus for eliminating micro-organisms,
as constructed in a compendious and convenient form for eliminating micro-bodies
and micro-organisms from impure water, so as to render the same potable. Figs, 2, 3
and 4 shews the details hereof. Fig. 5 shews a horizontal section, and fig. 6 a
vertical section of a modified construction of the separator of increased eliminating
power and in particular suited for separating micro-organisms and bodies from
gases, atmospheric air and the like; Figs 7 and 8 shew the details hereof. Fig. 9
shews a longitudinal section of an auxiliary apparatus for mixing and sorting the
reduced microliths. Fig. 10 shews an apparatus for producing the micro-
membranes. Fig. 11 shews a small part of a micro-membranes to a greatly
magnified scale; figs. 12, 13, 14, 15, 16 and 17 are various micro bodies enlarged
to the same scale.
If microliths, preferably microliths of talc, such as are known in trade as stick
asbestos asbestos fibre or Bostonite are reduced under water, small fibres are
obtained that are finer than cocoon silk or spiders web and not thicker than from
0.00012 to 0.000,051 (0·003 to 0.0013 /m) but which are from 10,000 to
100,000 times as long as they are thick.
The splitting of the stick asbestos into its finest particles is best effected by
means of a roller mill whose rolls have only a rolling action and no, or very slight
sliding or grinding action, and which work under water and exert a pressure of at
most 11 lbs (0.5 kilogrms) per 0.16 square ins (1 square cent/_) of roller surface.
The splitting of the Bostonite is best effected by a so-called whole stuff rag engine,
such as is used in paper making the roller blades of which may approach the fixed
blades to within a distance of 00197 ins. (0·5/m) The asbestos thus prepared is
separated by deposit in apparatus, such as is shewn in fig. 9, according to the size
of the particles. This apparatus consists of a vertical drum with a stirring
apparatus, the axis of which is tubular at the lower end and is provided with
holes at a a¹ a. The pipe b with cock c is vertically adjustable in this axis.
This apparatus is charged with asbestos from the rag engine or roller mill
through the opening d to such an extent that the weight of the water therein is
from 1000 to 2000 times that of the weight of the dry asbestos.
The stirring apparatus is then rotated by a ball pulley e or by other means
(about from 30 to 60 revolutions per minute) and according as the asbestos is to
be sorted into a greater or less number of degrees of fineness, it is allowed to
subside for from 15 to 30 minutes. In order to withdraw the finest particles first,
the pipe 6 is so adjusted that the liquid with the suspended microliths can only
flow off through the holes a a, the cock c being opened. On then closing the cock,

page_text: '
The
the pipe is adjusted with its upper opening level with those a¹ a' and the cock
being opened again, the liquid is drawn off in a separate receptacle.
remainder being then drawn off through a a², this is again subjected to reduction.
Thus, by the system of reduction employed, and by means of the adjustable
tube b in combination with apertures such as a a' a³, Fig. 9, the size of the asbestos
particles can be regulated according to the density and fineness of the micro-
membrane required.
The fibrous material thus obtained can however not be employed directly for the
purpose in question. It must be attached to a support, for which purpose metallic
wire gauze is best suited, which is prepared and mounted as follows:-A wire
gauze of about 0.0078 (0.2 m/_) linear opening in the mesh and about
0.00355 (0.09 m/m) thickness of wire is stretched either over a metal frame,
Figs. 2 and 3 or on a metal grating figs. 7 and 8. These frames or gratings may
be square, round, oval or other shape.
Fig. 2 shews a longitudinal section and plan of a stamped frame f on which the
wire gauze g is fixed by placing the frame on a fixed base h, Fig. 3, and, after
laying the wire gauze g upon it, pressing the metal frame k provided with leather
packing down upon it, whereby the wire gauze will be stretched perfectly
smooth. The frame k must be pressed down until its upper surface is flush with
or preferably slightly below that of the frame f in order to be able to press upon
the latter and on the wire gauze another frame f¹. The surplus edge of wire
gauze is then cut off. For stretching wire gauze over the metal grating fig. 7,
the former is first stretched flat in another frame, not shewn, and is then placed
with the frame on the grating, whereupon the frame fs. is secured to the grating
by rivets or otherwise, so that the wire gauze becomes stretched to the required
degree. Two gratings thus prepared are then placed with the wire gauze surfaces
facing each other, as at fig 8, and are screwed together, a vulcanite or gutta
percha plate having been first placed between the wire gauze surfaces. In this
condition, the metal gratings or frames are placed in an electroplating bath and
are allowed to remain until the wire gauze has become stiffened by the metallic
electro deposit at the point of interlacing of the wires, and the wire gauze is also
in metallic connexion with the metal frames or gratings. Without this operation
of electroplating the wire would not be rigidly connected with the metal frame
nor would the single wire threads be unremoveably connected with one another.
After this operation, the whole forms a stiff and rigid porous plate. The gratings
are then separated from each other, and each grating is separately treated in the
bath again in order to obtain a uniform deposit. By this means a porous
homogenous metal plate which forms the bed of the micro-membrane is obtained.
Upon this bed, the above described fine fibre material is deposited by subsidence
and is connected thereto in the following manner. The metallic bed is placed
with the wire gauze uppermost in the sediment frame fig. 10. ff¹ is the section
of the membrane bed. The upper edge of the sediment frame must be at
least 0.196 (5"/m) above the top of the membrane bed, and the bottom must
have an opening m, which is just as large as the wire gauze surface above it.
This frame rests with its feet n loosely upon the bottom of the sediment vessel A
and has a fixed solid partition o, which only serves to prevent the formation of
eddies above the discharge pipes p and p', when letting off the sediment liquid.
After the membrane bed has been placed in the sediment frame, 7 and the latter
has been placed in the vessel A, the stirring apparatus q is lowered in the latter to
such an extent that the horizontal perforated pipe r is situated from 0-6 ms (15°/m)
to 0.98 25%) from the membrane bed; a liquid consisting of one part by weight
of a solution of soda or potash water-glass of 1.25 to 1.30 specific gravity with
100 parts by weight of water is poured in a boiling condition through the pipe 8
so as to stand above the sediment frame and to drive all air bubbles completely
out of the membrane, whereupon the sediment vessel is filled with the same liquid
mixture in a cold condition up to above the perforated pipe r.. The asbestos
particles or generally the mass of microliths to be employed for the micro-

page_text: membrane is introduced into the stirring apparatus through the opening 9,
together with a mixture of water glass and water, in such proportion that, on
discharging the whole contents of the stirring apparatus into the vessel A by
opening the cock q¹, 3000 to 4000 parts of liquids having 5 per cent water glass
of 1.25 to 130 specific gravity are made to contain 1 part of dry. microliths.
Before opening the cock q¹, the stirrers are rotated for at most 1 to 1'/, minutes at
a speed of about 30 revolutions per minute. After the stirrers have stopped, the
cock q' is opened, and the mass is allowed to flow through the piper into the
sediment vessel, care being taken that no frothing or formation of air bubbles in
the liquid takes place, and that the sediment vessel is supplied as uniformly as
possible. The stirring apparatus is now taken out and the sediment vessel is
covered by a plate and allowed to rest. With coarse fibre material or microliths
the subsidence takes from 1 to 1/2 hours; with finer materials, from 6 to 12 hours,
and even longer. After this time, a very loose layer, similar to light snow will
be observed with the naked eye at the bottom of the vessel. After the deposit
has been effected, the cock of the pipe p, whose restricted opening extends to just
under the plate o is opened.
The discharge of the liquid must not take place with shocks, and generally
speaking it must only be effected at such a speed as though the whole of the liquid
had to pass through the layer of microliths, because the liquid will only find its
way through the micromembrane when the level thereof has sunk to the level of
the upper flange of the sediment vessel l. Before that time the liquid flows off at
the periphery of the sediment frame. The apparatus should also stand on the
ground in order to avoid all vibrations. Several sediment frames may be arranged
side by side in one sediment vessel.
.
On the completion of the depositing process, the whole sediment frame
inclusive of the micro-membrane formed and the metal bed is placed in a drying
stove and dried at a gradually increasing temperature rising to from 212°
to 248° Fabr., until a uniform white shining surface is observable with the naked
eye. By this drying process a peculiar change is effected in the loose fibres and
microliths lying upon the metal gauze, owing to their applying themselves closer
to the surface thereof. The thin films of water glass solution which connect the
microliths with each other, tear by the drying, and form inorganic connexions
between the microliths. By the tearing by drying of the water glass, fine porous
openings are formed, without which the filter consisting of microliths could not
act. After cooling the micromembranes together with the metal bed, these
together with the sediment frame 1, fig. 10, are placed in a vessel constructed just
the same as the vessel A. Several sediment frames with dried micromembranes
can be placed in this vessel if metal gratings are placed upon them to support the
feet n of the superposed frames
After the dried micromembranes are placed in the vessel, a solution consisting
by preference of three parts by weight of calcic chloride to 100: parts of water are
poured into the vessel A through the pipe p, just as slowly as it was previously
drawn off. Instead of calcic chloride, chloride of magnesium or chloride of barium
can be employed. The membranes are left in this bath for from 4 to 6 hours, and
during this time a microscopically observable change also takes place, which is of
the greatest importance. The before mentioned films of water glass dissolve
somewhat, and roll up exceedingly small globules and attach themselves, under
occlusion of common salt, in the form of micro-crystals of silicate of lime barium, or
magnesia, to the microliths, so as to serve as an inorganic connection to these.
Fig. 11 shews a portion of a layer of the microliths, connected by the said micro-
crystals, whereby the asbestos fibres assume the appearance of being covered with
warts and receive a rough surface. This layer has been found by optical
measurement and calculation to be about 0·00127 (0.0323 /m) thick at its
thickest part, and from 8 to 10 such layers form a diffuse surface which is quite
mpenetrable for the rays of light of the microscope. In order to judge readily of
the proportionate size of the microlith fibres I have, at fig 12, shewn a globule of

page_text: human blood, at fig. 13 a cell of beer ferment, at fig 14 a mildew spore, at fig. 15 &
thread of cocoon silk, at fig. 16 a spiders web, and at fig. 17 a fibre of bostonite
enlarged in the same proportions as the portion of a microlith layer, shewn
at fig. 11.
After fixing by means of the chloride of calcium bath, the liquid is allowed to
flow off slowly through the pipe p¹, and the micromembrane is placed, without the
sediment frame, in a vertical position in pure water in order to remove the soluble
salts from the micromembrane. If it be desired to obtain very fine and dense
micromembranes the same depositing and cementing processes as above described
may be repeated once or twice on the same membrane, the finer and the finest
microliths being successively deposited, and by this means it is possible to obtain
an inorganic membrane, which, at about 001 (0.25 m) to 0·012 (0.30 /)
thickness, has on the outer layer of 0.002 in (0.005 m/m) thickness for every
0.0013.º9.
9. in (1 square /m) from 300,000 to 400,000 microapertures, so that in con-
sequence of the fineness of the microliths and diffused portions thereof, about one
third of the membrane surface may be considered as open surface, thus offering to
the passage of liquids or gases, on account of the great thinness of the membrane,
no other resistance than the coefficient of friction of fibrous bodies.
Before proceeding to the statement of the eliminating powers of the micro-
membranes, it should be stated that about from 0.11 grains to 0.15 grains
(7.5 to 10 milligramme) dry asbestos are required for every 0·0015 (1 sq m)
of membrane surface of a thickness of from 0.001 to 0.012. In order to obtain
greater durability, two micromembrane plates or so-called micro-membrane elements
are connected together with their membrane surfaces facing each other, the edges
of the frames being cemented together watertight by means of india rubber
solution, the gratings, when used, having the flanges screwed together as at figs. 7
and 8, while, with frame membrane beds, the frames are connected as at fig 4.
Such a combination is termed a membrane system and it can be used in any desired
position for eliminating the micro-bodies and micro-organisms. It acts both as
bottom plate, as cover, or as side walls for chambers, whether the liquid or gas
passes from the interior to the outside or conversely.
With reference to the construction of apparatus, for instance, with the view to
eliminate from the air micro-bodies and to render impure water potable, the
apparatus shewn at fig 1 with the double membrane system is best suited, con-
sisting of two opposite membrane systems u u connected at their rims and having
a siphon v. If this apparatus is placed in a reservoir B and the air is exhausted
from the siphon, the liquid to be freed from micro-bodies and micro-organisms,
indicated by horizontal lines, flows in the direction of the arrows through the
micro-membrane system, and flows off at c¹ with a very small difference of levels.
A difference of level between C and C¹ of from 9 is to 11 in (20 to 25 cm) is sufficient,
with the most dense membrane to pass through 0·15 вq ins (1 sq.m.) of membrane
surface 0.024 cub: ins. (0.39 cub cm) of water per minute.
The apparatus shewn at fig. 1, which is particularly suitable for portable purposes,
is provided with a casing of stamped sheet steel w provided with suction apertures
1, 2, 3, 4. The size of the siphon pipe should be so calculated as only to pass as
much water as can be yielded by the entire micro-membrane surface.
These double membrane systems may be used in any size, both as apparatus for
travellers, troops, etc, and for the supply to towns, etc.
When the outer surface of the membrane has become coated with impurities
through use it can be cleaned by sluicing or for small apparatus by lightly
brushing with a feather brush. If the apparatus has become quite unusable, the
parts of the micromembranes consisting of the microliths can be removed and
replaced by new ones, while the metallic portions can be re-used repeatedly by
slightly electroplating them again.
Fig. 5 shews a horizontal section and fig 6 a vertical section of a quadruple
membrane system, formed with the above described grating beds, and consequently
suited for a very considerable eliminating power.

page_text: This construction is more particularly suitable for the removal of micro-organisms
and bodies from gases, atmospheric air &c, the parts shewn by horizontal section
lines again representing the gas or liquid.
Having thus described the nature of this invention and in what manner the
same is to be performed, as communicated to me by my foreign correspondent, I
claim:-
First: The method of producing micro-membranes for eliminating micro-bodies
from liquids and gases, consisting in the deposition of microliths upon a porous
diaphragm or backing substantially as described.
Second: The method of producing micro-membranes for eliminating micro-
bodies from liquids and gases, consisting in the deposition of microliths upon a
porous diaphragm or backing, to which they are connected by an inorganic
substance without destroying their porosity, as described.
Third: The herein described process of producing membranes or media for
eliminating micro-bodies from liquids and gases, which consists in depositing finely
reduced asbestos upon a porous backing and attaching the same to said backing by
an inorganic substance.
Fourth-The herein described process of producing membranes or media for
eliminating micro-bodies from liquids and gases, which consists, first, in forming a
uniformly porous metallic backing by treating wire gauze in an electrolytic bath
so as to obtain a metallic deposit for the purpose specified, then depositing upon
the prepared backing a finely reduced inorganic fibrous substance, and lastly
connecting the same to the backing, as set forth.
Fifth: The herein described process of producing membranes or media for
eliminating micro-bodies from liquids and gases, which consists in first depositing
upon a porous metallic backing, by subsidence in presence of soda or potash water-
glass, finely reduced asbestos, then subjecting the same to the action of heat and
finally to that of chloride of calcium or its specified equivalents, substantially as,
and for the purposes described.
Sixth: The process of reducing asbestos into finely divided fibres, which consists
in subjecting the same to pressure, or to pressure and friction, while submerged in
water substantially as and for the purposes specified.
Seventh: The use for eliminating micro-bodies from liquids and gases, of
membranes or media composed of microliths deposited upon a porous backing
substantially as and for the purposes herein described.
Eighth The use of separating apparatus consisting of the vessel B¹, shaft S
provided with stirrers S¹ and discharge ports at different elevations in its hollow
portion in combination with the discharge pipe b adjustable vertically within the
hollow part of shaft S, substantially as and for the purposes specified.
Ninth The depositing vessel consisting of the vessel A having pipes S₁ p p', in
combination with the vessel B'. having a piper and the stirrers g, all constructed
for co-operation substantially as shown and described.
Tenth Constructing apparatus for eliminating micro-bodies from liquids and
gases, of one or more micromembranes consisting of a porous backing having a
coating or deposit of finely divided asbestos arranged for operation substantially as
herein described with reference to the accompanying drawings.
In Witness whereof I the said Charles Denton Abel have hereunto set any
and and seal this twenty third day of October in the year of our Lord one
housand eight hundred and eighty-three.