Year: 1895

page_text: Date of Application, 8th July, 1895-Accepted, 24th Aug., 1895
I ALBERT LUDWIG GEORG DEHNE of Halle on the Saale in the Empire of
Germany, 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 :-
In filterpresses with means for washing or rinsing them out, the fluid used for
washing or rinsing is supplied through a port, from which branch off ports
alternately to opposite sides of the plates, and which supply the fluid to the filter
cloths in their respective chambers.
The fluid penetrates the filter cloth and the press residues, and also the
opposite cloth, and then flows away to a suitable place with the washed-out
products.
If, however, during the ordinary filtering process, previous to the washing out
of the press, a cloth tears or bursts, the mass to be filtered gets behind the cloth,
and thus, through the small side passages, into the common wash-out passage, and
from their again back through the side passages of the other plates, behind the
cloths in the other chambers, whereby filtered and unfiltered materials are mixed
up and run off together, the filtering process being thereby brought to a stand still.
In general, with filter presses of the usual construction, the difficulty has been
got over by replacing the waste tap by a settling chamber, such chamber being
capable of isolation during filtration." In filter-presses with the system of wash-out
passages above described, this, however, will not answer, as the intermingling of
filtered and unfiltered liquids cannot be prevented.
The filtering process has then simply to be stopped, to clean out the press, to
obtain a perfectly clear filtrate.
In order, therefore, to overcome this evil with respect to presses of the above
described construction of wash-out passages, should a cloth burst or tear, according
to the present invention each one of the small branch passages o of the common
feed passages a for the washout fluid for each plate is furnished as represented in
the accompanying drawing, with a special cut-off i, and the outlet passages b and d
of each plate for the wash-out fluid and air, are also provided each with a separate
cut-off cock.
While the filtration is going on, all these cut-off cocks in the passages o, b, and d,
are closed, and the filtration proceeds in the usual manner, the material to be
filtered entering through the central passage e, and the filtrate going off through
the open passages c.
Should the filtrate issuing from any chamber appear cloudy, through a defect in
the cloth, the corresponding tap in the outlet passage c, and the cock i in the side
passage o, are turned off, thereby cutting the chamber out of the filter series, and
preventing the unfiltered liquid from getting through the side passages, and behind
the cloths in the remaining chambers.
The filtration can in this way be continued to the end with the remaining
chambers only.
Whilst the passage o of the chamber which runs cloudy is cut off, it is at the
same time isolated, and can be washed or rinsed out.
This is effected by shutting off the supply of unfiltered liquid, and also the
several passages c and the taps i, and opening the taps of the passages band d,
with the exception of the tap of that chamber from which the filtrate was thick.

page_text: The wash-out liquid enters the common passage a, branches off through the
passages o, penetrates the chambers, and drives out the air through the open taps
of the passage b (which, after all the air has been driven out, is shut again), and
then goes off, with the residues, through the passages d, into the gutters provided
for carrying it off.
The two Figures 1 and 2 show the alternate arrangement of the passages
for the plates 1, 3, 5, and so on, and for the plates 2, 4, 6, etc.,-Fig. 1A being a
section of Fig. 1.
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 :-
In a filter-press of that class which has means for washing or rinsing out the
residues of the filtering operation, providing the inlet and outlet passages for the
washing-out water, with cut-off cocks, for the purpose of cutting out any single
plate (or chamber), either whilst filtering or washing out, as herein described.
Dated this 6th day of July 1895.
NEWTON & SON,
Agents for the Applicant.