Improvements in the Purification of Gases.
Year: 1888

page_text: Complete Specification Left, 17 Sep
PROVISIONAL
SPECIFICATION.
Improvements in the Purification of Gases.
I, ERNEST SOLVAY, of 19 Rue du Prince Albert Brussels, in the Kingdom of
Belgium, Manufacturer, do hereby declare the nature of this invention to be as
follows:
Much trouble has often been experienced in freeing certain gases from impurities
contained in suspension therein in the form of impalpable dust or of vapor in the
vesicular state. In such cases recource has usually been had to depositing chambers
which afford to the substances in suspension time to deposit or precipitate by
reason of the state of relative rest of the gases resulting from the use of such
"washed" by being
chambers. In other cases the gases have been purified or
caused to pass through a suitable liquid. It has also been proposed to use electricity
to effect the purification also to cause the currents of the gases to be purified to
impinge against an obstacle and to forcing the gases to pass through small orifices or
passages. The desired purification has however been effected only very imperfectly by
means of the ordinary depositing chambers even when these have been furnished with
baffle plates. The gaseous current always chooses the easiest and most direct path or
passage along which it flows with scarcely diminished velocity whilst the remainder of
the space in the depositing chamber is only utilized to a very small extent and does
not play any active part in removing the impurities..
In order to effect perfect purification the current of gas to be purified is caused,
according to this invention, to pass through filtering material having a large surface,
through which it is obliged to spread equally by dividing itself up into very small
currents in order to find channels for its free passage. The extent of surface of the
filter the depth or thickness of the filtering material and the size of the grains or
particles composing the same, are proportioned. in such a manner as to leave a passage
of considerable total sectional area whilst offering sufficient resistance to prevent
concentration of the current of gas towards any part affording an easier passage.
The flow of the gases is from the bottom to the top of the chamber whereby dust or
other bodies in suspension in the gases can be deposited without choking or soiling the
filtering partition as soon as their velocity has become low enough; and can be after-
wards withdrawn from the lower part of the chamber. The filtering partition may
however be arranged vertically and the gases caused to pass laterally; or the gases
may be caused to radiate from the interior towards the circumference of the chamber
or vice versa.
If the gases in passing upwardly have a tendency to make for themselves flues or
passages through which they may flow more easily they may be caused to pass in a
downward direction. In this case however the surface of the filtering partition will
become soiled by the impurities removed from the gases and such partition should be
arranged in such a manner as to be accessible for either intermittent or for continuous
cleaning operations. The filtering medium or material may be composed of any
suitable substance; it may be granular or fibrous and be arranged in various ways.
If it be desired to purify a condensable vapour the filter may be provided with a
double casing or envelope which admits of its being maintained at the temperature
necessary to prevent condensation from taking place in its interior. A suitable filter

page_text: according to this invention in which the filtering medium is arranged approximately
horizontal may be constructed as follows:-A cylindrical chamber or vessel of metal,
sandstone or other suitable substance and with or without a steam jacket, a furnace or
other heating device is furnished with a cover on which is arranged an inlet pipe for
the gas or gases to be purified.
The outlet pipe is arranged at the bottom of the chamber or vessel. A perforated
diaphragm placed above the outlet orifice supports the filtering medium which com-
prises a layer of small pebbles above which is a bed of gravel of gradually increasing
fineness and passing gradually into sand which occupies the remainder of the thickness
of the filtering medium. A manhole is provided to allow of a periodical scraping or
raking of the upper surface of the sand for renewing the surface. If desired the
apparatus may be fitted with an internal rake or scraper mounted on a central vertical
shaft in such a manner as to effect the cleaning during the working of the filter. It
is to be understood that according to this invention there is in addition to the precipi-
tating or depositing action a filtering action due to the small passages formed by the
grains or particles of the filtering material.
These passages are fine enough to mechanically retain the impurities in suspension
and this second principle is believed to be novel in its application to the purification of
gases and vapours.
Dated this 18th day of December 1888
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Purification of Gases.
I, ERNEST SOLVAY, of Brussels, in the Kingdom of Belgium, Manufacturer, do
hereby declare the nature of this invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:
Much trouble has often been experienced in freeing certain gases from impurities
contained in suspension therein in the form of impalpable dust, or of vapor in the
vesicular state. In such cases resource has usually been had to depositing chambers
which afford to the substances in suspension, time to deposit or precipitate, by reason
of the state of relative rest of the gases resulting from the use of such chambers. In
other cases the gases have been purified or "washed" by being caused to pass through a
suitable liquid. It has also been proposed to use electricity to effect the purification ;
also to cause the currents of the gases to be purified, to impinge against an obstacle ;
and to force the gases to pass through small orifices or passages. The desired purifi-
cation has however been effected only very imperfectly by means of the ordinary
depositing chambers even when these have been furnished with baffle plates. The
gaseous current always chooses the easiest and most direct path or passage along
which it flows with scarcely diminished velocity whilst the remainder of the space in
the depositing chamber, is only utilized to a very small extent and does not play any
active part in removing the impurities. In order to effect perfect purification, the
current of gas to be purified is caused, according to this invention, to pass through
filtering material having a large surface, through which it is obliged to spread equally
by dividing itself up into very small currents in order to find channels for its free
passage. The extent of surface of the filtering material, the depth or thickness of such
material, and the size of the grains or particles composing the same, are proportioned
in such a manner as to leave a passage of considerable total sectional area, whilst
offering sufficient resistance to prevent concentration of the current of gas towards
any part affording an easier passage than other parts of the filter.
The arrows in the annexed drawings illustrate diagrammatically the difference
between the action of an ordinary depositing or purifying chamber shown in Fig 1

page_text: and a despositing or purifying chamber provided with a filtering partition according
to my invention and shown in Fig 2.
The flow of the gases may advantageously be from the bottom to the top of the
chamber as shown, so that dust or other bodies in suspension in the gases can be
deposited without choking or soiling the filtering partition as soon as their velocity
has become low enough and so that they can be afterwards withdrawn from the lower part
of the chamber. The filtering partition may however be arranged vertically, and the
gases be caused to pass laterally; or the gases may be caused to radiate from the
interior towards the circumference of the chamber or vice versa.
If the gases in passing upward have a tendency to make for themselves flues or
passages through which they can flow more easily, they may be caused to pass
in a downward direction. In this case however the surface of the filtering partition
will become soiled by the impurities removed from the gases, and such partition
should be arranged in such a manner as to be accessible either for intermittent or
for continuous cleaning operations. The filtering medium or material may be
composed of any suitable substance; it may be granular such as sand or fibrous
such as asbestos and be arranged in various ways. If it be desired to purify a.
condensable vapour the filter may be provided with a double casing or envelope
'to contain heated fluid whereby the filter can be maintained at the temperature
necessary to prevent condensation from taking place in its interior. A suitable
filter according to this invention, in which the filtering medium is arranged approxi-
mately horizontal, may be constructed as follows:-A cylindrical chamber or vessel
of metal, sandstone or other suitable substance and with or without a steam jacket,
a furnace, or other heating device, is furnished with a cover on which is arranged an
inlet pipe for the gas or gases to be purified. The outlet pipe is arranged at the
bottom of the chamber or vessel. A perforated diaphragm placed above the outlet
orifice supports the filtering medium which comprises a layer of small pebbles above
which is a bed of gravel of gradually increasing fineness and passing gradually into
sand which occupies the remainder of the thickness of the filtering medium. A
manhole is provided to allow of a periodical raking of the upper part of the sand for
renewing the surface. If desired, the apparatus may be fitted with an internal rake
mounted on a central vertical shaft in such a manner as to effect the cleaning during
the working of the filter. It is to be understood that according to this invention there
is, in addition to the precipitating or depositing action, a filtering action due to the
small passages formed by the grains or particles of the filtering material. These
passages are fine enough to mechanically retain the impurities in suspension, and this
second principle is believed to be novel in its application to the purification of gases
and vapours.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed, I declare that what I claim is :-
1. The process of purifying gases or vapors from dust or vesicular matters contained
in suspension therein by the deposition obtained by causing the gases or vapors to pass
through a filtering partition of large surface arranged to divide a depositing chamber
through which the gases or vapors are passed.
2. The process of purifying gases or vapors from dust or vesicular matters contained
in suspension therein by the filtration of the gases or vapors through a sufficient
thickness, bed, or layer of sand or other suitable granular or fibrous substance.
Dated this 17th day of September 1889.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.