AN IMPROVEMENT IN FILTERING-APPARATUS
Year: 1884

page_text: I, JOHANN KROOG, of Halle-on-the-Saale, in the Kingdom of Prussia, Civil
Engineer do hereby declare the nature of my invention for "AN IMPROVEMENT
IN FILTERING-APPARATUS" and in what manner the same is to be perforined, to
be particularly described and ascertained in and by the following statement:-
This invention relates to improvements in filtering-apparatus, or filter-presses.
If out of a mixture of liquid and solid substances the latter are to be obtained in
the shape of cakes, the difficulty often arises that the said cakes thus obtained are
not homogeneous in all their parts, and that the upper parts of the said cakes are
softer, or less compact than the lower parts of the same. This difficulty being of
great importance under all circumstances, it will become the more so in all such
cases where the cakes obtained by means of filtration are to be subjected to a
further treatment, by subjecting them to the action of some liquid or fluid, while
yet in the filter-press.
Now, my present invention is intended to obviate all these difficulties, and its
object is to produce entirely homogeneous cakes, first, by a novel construction of
the filtering-plates, second, by providing a wind or air-pipe, having a stop-cock,
upon the frames serving for the reception of the mixture of liquid and solid
substances, and third, by an entirely novel method or mode of working.
In the accompanying drawing.
Figure 1 is a filtering plate provided with fine vertical grooves.
Figure 2 is a horizontal section of the same, on the line a, b.
Figure 3 is a vertical section of the same, on the line c, d and of the filter frame
shewn in Figure 4.
Figure 4 is an elevation of the said filter frame.
Figure 5 is a transverse section, drawn to an enlarged scale, of a number of
plates and frames shewing the order of the latter and the position of the channels,
or passages, in the joining flanges of the said plates.
Figures 6 and 7 illustrate a modified form of a filtering plate, and
Figure 8 is an elevation of the frame for the same.
In Figures 1 to 5 inclusive S indicates the channel, or passage, for the said
S
mixture of substances, u u the inlets for the said mixture from the passage
into the interior of the frame r, and the stop-cock of the air-pipe, having'a
suitable basin or receptacle arranged upon the upper part of the said frame.

page_text: I wish it to be understood that I am aware of the fact that filtering-plates
provided with fine grooves, are old, and that they have been applied for the reason
that they offered advantages as compared with filtering-plates covered with
perforated sheet metal, by reason of their larger filtering area. Yet notwith-
standing these advantages they have been but seldom used, partly on account of
the difficulty met with in their manufacture, and partly because they were liable to
burst on increasing, but inconsiderably, the pressure or temperature, by reason of
the channel, or passage, cast into their lower part, and by reason of the circum-
stance that the connection between their lower rims and their central parts was
established by nothing else except by the thin ribs between their said grooves.
Besides, the cleansing of the said passage cast into the said plates, was most difficult.
All these difficulties are obviated with the plates constructed in accordance with
the principles of my present invention. With the plates of my said improved
construction the liquid filtered is educted from the said grooves by means of small
conduits narranged vertically in any convenient number near the lower side of
the said plates, and enters the lateral passages or channels o countersunk into both
sides of the joining flanges of the said filtering-plates, whence the said liquid will
flow off through the cock h provided near one corner of each plate. The filtering-
cloth t extends beyond the said lateral channel o and also beyond the lower rim of
the plate and frame r.
It is evident that by the construction described, a most perfect eduction of the
filtered liquid from the said vertical grooves is obtained, and that consequently,
the cakes in the said frames will be formed so as to be perfectly uniform, and
that, furthermore, the said plates offer no difficulty in their manufacture and
cannot burst.
Now, in order to entirely secure the uniformity in the formation of the cakes
from the very beginning, it is necessary to have all the frames filled completely
at the beginning of the filtering-process. This condition is arrived at by the use of
the stop-cock of the said air-pipe arranged upon the frames r, and by means of
the following method, or mode of working, that is to say:-
All the outlet cocks h of the filtering-plates p are closed before opening the
inlet-valve, provided near the end of the passage S, through which the mixture of
liquid and solid substances is to enter the frames r; and at the same time all the
air-cocks upon the said frames are opened. This being done the inlet valve of
the passage S is opened slowly so as to allow the said mixture of liquid and solid
substances to enter the frames r through the said passages S and its outlet-
conduits u u. The said mixture on entering the frames r will expel therefrom the
air which will leave through the opened air-cocks L, and this will continue until it
will be noticed from the appearance of the upper part of the said mixture of
substances in the said basins above the air-cocks that the charge of the frames r is
completed. Now, the said inlet-valve of the passage S is closed, whereupon the
air-cocks will be closed likewise, and this being done the outlet-cocks h of the
plates are opened. The inlet valve of the passage S is then opened again to its
fullest extent so as to allow the stream of mixed substances to enter the frames r
again. The filtration which could not take place before (by reason of the opened
air-cocks ) now commences, and the formation of entirely homogeneous cakes will
take place because the filtered liquid can readily flow off from all the spaces of the
said grooves in the plates p and, for the reason that the frames r were completely
filled at the beginning of the filtering process so that no air could influence the said
formation of the cakes with any noxious effect.
The small quantities of the mixed substances having remained in the basins of
the air-cocks on closing the same, will escape, on opening the said cocks before
the commencement of a fresh filtering-process, into the then emptied frames r.
In the modified arrangement illustrated in Figures 6, 7 and 8 of the drawings,
the said outlet-cocks h are substituted by the channels and u, while the
inlet-passage for the mixture of solid and liquid substances is indicated by the
letter m.

page_text: Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
First The combination, with the grooved filtering-plates, of the open lateral
channels o arranged on both sides of the said filtering-plates in the joining flanges
of the same, and serving the purpose of educting the filtering liquid and allowing
of introducing liquids or fluids into the frames r, substantially as set forth.
Second. The combination, with the frame r, of an air-cock having a basin, or
receptacle, substantially as, and for the purpose, specified.
Third The method, or mode of working, employed in producing entirely
homogeneous cakes, substantially as, and for the purpose, herein described.
Dated this 17th day of September 1884.
HASELTINE, LAKE & Co.,
For the Applicant.