Process of Making Sterilized Filters and Filtering Surfaces.
Year: 1895

page_text: Date of Application, 31st.Jan., 1895-Accepted, 16th Mar., 1895
COMIDELE
Process of Making Sterilized Filters and Filtering Surfaces.
OTTO WILHELM BRANDENBURG, Merchant, and FRIEDRICH HERMANN POTT,
Chemist, trading under the Firm of Otto Brandenburg & Co., both of
44 Chausséestrasse, Berlin, do hereby declare the nature of our said invention and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This invention relates to a process of condensing filtering surfaces i.e. to render
same more effective (or less impervious) and at the same time to sterilize same.
Such filters are specially adapted for the filtration of water, as they supply an
excellent drinking water which is free from bacterial or micro-organisms.
The condensation or filling out of the filtering surfaces of the filter, is effected by
a powder or sludge of finely reduced carbon, sand, fossil meal, asbestos or other
suitable substance held in suspension, which settles and finely distributes itself on
the filtering area or surface. This condensation of the filtering surfaces by the
deposited filtering material may be carried out so as to effect at the same time a
sterilization of the filtering material, by depositing the latter with the aid of hot
water.
The high temperature of the water holding the filtering material in suspension
destroys all germs and causes the filter itself i.e. the arrangement or device receiving
the filtering surfaces, to be sterilized simultaneously with the condensation or
settling of the suspended substance.
Such sterilized filters are made in the following manner. The carbon or other
filtering material is put into a vessel along with hot water and is constantly stirred
until a sludge or pulp is formed which latter is fed to the filter in a suitable manner
for instance by means of a suction or pressure pump. The filtering material thus
fed in a very fine and uniform state settles on the filtering surfaces and renders same
more compact or condensed, the action of the filter being thereby very considerably
increased. By means of the hot water causing the filtering material to settle,
both the filtering material and the filter itself are freed of all germs or
organisms.
By dissolving salts in the hot water, the specific gravity of the liquid holding in
suspension the filtering material, may be increased; the particles consequently remain
better in suspension.
All the known filtering arrangements best adapted for the said purpose of the
filter, may be employed.
For filtering water on a large scale, it is preferable to make the filter of the
form of the known filter-presses. According to this invention the capacity i.e. the
supplying of a sterilized filtrate, is increased by allowing a layer of finely distributed
carbon or the like to settle on the filtering surfaces of the filter press in the
manner aforedescribed, by means of hot water.
Having now particularly described and ascertained the nature of our inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
Process of making sterilized filters and filtering surfaces and simultaneous con-
densing the latter, consisting in causing the filtering material (carbon sand,

page_text: asbestos or the like) held in suspension to settle on the filtering surfaces by means
of hot water, or a hot solution of a suitable salt, substantially as described.
Dated this 31st day of Januarv 1895.
W. P. THOMPSON & Co.,
31, High Holborn, W.C., Patent Agents for the Applicants.