Improvements in the Production of Solution of Alkaline Silicate or Water-glass, and in Apparatus therefor.
Year: 1890

page_text: Date of Application, 14th Mar., 1890-Accepted, 19th Apr., 1890
COMPLETE SPECIFICATION.
Improvements in the Production of Solution of Alkaline Silicate or
Water-glass, and in Apparatus therefor.
A communication from PAUL SIEVERT, of Dresden, in the Empire of Germany.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., 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 :-
The well known and usual process of dissolving water-glass mainly consists in
mixing the material such as is supplied by the trade-in lumps or powder with water
and treating it for several hours by steam in suitable chambers during which treatment
it is continually stirred. This process however can only be carried out at a profit by
means of extensivo industrial plant where the requisito machinery is within easy
reach. In addition to this, another difficulty arises in practising this method ciz. :-
that owing to the glass being boiled in the water for a considerable length of time the
solution becomes turbid-probably in consequence of the formation of neid
silicates and therefore requires subsequent fining or clarifying which of course
involves a loss of time.
It is for this reason that in many industries and notably in the soap manufacture
water-glass is purchased directly in solution. But this has the disadvantage of un-
necessarily increasing the cost of warehousing and treatment seeing the considerable
percentage of water which is contained in water-glass supplied in this form; besides
a variety of other drawbacks.
Now the object of this invention is a process which will enable water-glass to be
purchased by manufacturers in lumps and a solution of the required strength to be
obtained on the spot without necessitating any special provision steam being
the only agent required and this heing in most casos constantly at hand as is
well-known.
This novel process mainly consists in first softening (partly dissolving) the lumps of
water-glass by intimate contact with the steam, and then constantly moistening them
by means of a spray of water or any suitable alkaline lye, while the solution is
discharged and collected as it forms. By causing the solution before it is discharged
to flow a greater or less distance over the softened lumps it can be made more or less
rich at will.
This process also offers this important advantage that the solution thus continuously
produced at the desired degree of strength or richness, is perfectly clear and can at
once be used for any industrial purposo. This may be accounted for by the fact that
the formation of acid silicates which causes the turbidness may be avoided by placing
the water-glass in direct contact-if even for a moment only-with the water or lye.
This however is only possible when the pieces of glass are previously by an intimate
contact with steam inade capable of a rapid dissolution.
To carry out the process described I prefer to employ the apparatus shown in the
accompanying drawing in longitudinal section. It consists of an external boiler or
jacket a of an elongated shape surrounding a reservoir 6 with perforated walls.
In this reservoir, the lumps of water-glass are piled up loosely so as to form as high a
pile or heap as possible. By means of a special steam pipe c or a rose d steam under
a pressure of from 4 to 5 atmospheres is admitted into the boiler a and thereby the
pieces of glass brought into intimate contact with the steam which softens (partly
dissolves) them.
On one side of the boiler a a small boiler fis arranged into which opens a steam
pipe 9 and a water pipe h. As in the small boiler f the pressure is the same as in the
large boiler a the water (or the alkaline lye) must be forced into it by means of an

page_text: injector or pump. The steam by its downward pressure forces the water through
the rose d into the large or main boiler. The amount of water may be regulated
by suitable cocks which will also enable either the water or the steam or both to
be cut off when required.
The water or lye admitted in a spray descends on to the pieces of glass and performs
a washing action through which as it proceeds, it is converted into a solution more
or less strong according to the distance it is made to flow. When the liquid reaches
the bottom of the boiler a it issues through the pipe e. Into this pipe e it will be
necessary to arrange a condenser of any suitable construction so that the steam that
may be carried away along with the liquid may be condensed therein.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. A process for the continuous production of a clear solution of water-glass mainly
consisting in first softening or partly dissolving the lumps or pieces of water-glass put
up in a proferably high heap or pile within a perforated vessel, by means of steam
under pressure and of a spray of water or a suitable alkaline lye, the solution being
continuously discharged as it forms and acquiring the desired degree of richness by
flowing over the surfaces of the lumps of water-glass on its way to the discharge
orifice substantially as described.
2. The apparatus for carrying out the process described in the preceding claion
consisting of a boiler or jacket a surrounding or enclosing a reservoir such as b having
perforated walls and adapted for the reception of a preferably high pile of lumps or
pieces of water-glass in combination with a rose d arranged within reservoir b
near its open top substantially as described and illustrated in the accompanying
drawings.
DAL
↑
JEN