Improvements in or connected with Filtering Apparatus.
Year: 1898

page_text: Date of Application, 14th June, 1898-Accepted, 6th Aug., 1898
COMPLETE SPECIFICATION.
Improvements in or connected with Filtering Apparatus.
I, GOTTFRIED FLORACK, Building Contractor, of 120, Grafenbergerchaussee, Dus-
seldorf, in the German Empire, 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:-
This invention relates to a rotary drum filter in which the filtering media are
so arranged, that the liquid entering an initial or preparatory filter is conveyed
into a hollow shaft or the like, whence, after having been saturated with carbonic
acid, it is conducted to the finishing or supplementary filters which it enters; and
in order to avoid the necessity of arresting the filtration while the finishing filters
are being cleansed, an adjustable tube is fitted upon the said hollow shaft, which
tube, through the medium of a suitable coupling, connects each of the finishing
filters alternately with the hollow shaft, or similarly disconnects it from the same;
so that the liquid is at all times discharged only through one of the said finishing
filters, or where more than two such filters are provided through one set of
finishing filters, while the remaining filter or filters may in the meantime be
cleansed.
In the drawings:
Fig. 1 is a side elevation of a drum filter embodying my invention; Fig. 2 is a
plan, and Fig. 3 an end elevation of the same; Figs. 4 and 5 shown the preliminary
filter on a larger scale; Figs. 6 to 8 show the finishing or supplementary filters,
one of which is represented as communicating with the hollow shaft,
and the other as being cut off therefrom; Figs. 6 and 8. show also
the valves or flaps which prevent the material filtered off from re-entering the
hollow shaft; Fig. 9 is a separate view of the apparatus for cleansing the strainers.
The liquid to be filtered flows through the feed pipe into the case which is
closed in on all sides and contains one or more filtering drums n. These initial
filtering drums consist each of two halves separated from each other by a parti-
tion at right angles to the axis of the drum; and each half may in its turn be
divided into four sectors or compartments by four radial ribs, which, in revolving,
take round with them the liquid contained in the drum. The said initial filters
are mounted upon a hollow shaft a, which is supported in stuffing boxes s¹, 53, 53
and receives slow rotary motion through the medium of a strap pulley z (as illus-
trated in Fig. 1). The lateral apertures of the initial filter drums are kept closed
by means of straining cloths and strainers or sieves, which the liquid to be filtered
must penetrate, before it can gain admittance into the interior of the drums; after
which the liquid enters the hollow spindle a through apertures provided for the
purpose, and is thus conveyed to the finishing filter drums n¹ n³, mounted upon
the same shaft outside the case. In contact with the sieves or straining cloths
fitted in the sides of the initial filter drums, there are arranged stripping plates
or brushes (Figs. 4, 5 and 9), so as to sweep or brush the material remaining
behind after filtration off the said sieves or strainers, and to make it drop into a
receptacle k¹, whence such material or sediment is transferred by a screw conveyor q

page_text: into the mud collector. The scrapers are held in contact by their elasticity or by
other suitable means. Into this mud collector there may open a pipe serving for
the admission of hot water, so that the mud is here flushed through by the water
and any sugar or other soluble matter, that may still be contained in the muddy
sediment, is extracted therefrom and may be conducted to the macerating cistern.
In order to enable the carbonic acid, which has to be employed for the purpose
of separating the lime, to be supplied, before the liquid reaches the final filter,
a carbonic acid feed-pipe t is inserted into the pipe leading from the preliminary
to the final filter, and through it the liquid enters the said final filter. Upon
the shaft a is mounted a junction box made air-tight by means of stuffing boxes;
to which box is secured the above mentioned pipe serving to supply carbonic acid.
At the part of the hollow shaft, where the said box t is mounted, perforations are
provided all round, in order to permit the carbonic acid to gain access to the liquid
on all sides, so that it may mix with such liquid, and that the whole of the lime
added may be precipitated.
Instead of the hollow rotary shaft, a solid shaft might be employed, if preferred;
the liquid might be conducted from the initial to the final filters by a special
stationary pipe, and both the initial filters and the final filters might be set in motion
separately and independently of each other. In order to facilitate the cleansing
of the final filtering drums and to avoid the necessity of interrupting the filtration,
whilst the cleansing is in progress, there is fitted upon the shaft a an adjustable
tube or slide r, whereon the two finishing filter drums ¹, n² are placed loosely,
being however retained in position laterally by the holders e attached to the said
shaft, so that the said drums may revolve independently of the shaft, but cannot
slide thereon. The tube r, which the key p compels to participate in the rotary
motion of the shaft a, is capable of being shifted to the right and left by means
of a coupling g, by which movement one filter is set in operation, while the other
is thrown out of gear (as illustrated in particular in Figs 6 and 8). The finishing
filter drums are internally divided into compartments by radial ribs or ridges
which serve to impart circular motion to the liquid, each of the compartments
being provided with an aperture 2. In the final filter which happens to be in
operation at the time each of the apertures 03 is situated just over the aper-
tures o¹ and o, of the same size, formed in the tuber and in the shaft a respectively,
so that the liquid to be filtered may pass from the hollow shaft into the interior
of the several compartments of the filter, whence it is discharged through side
orifices which are covered by straining cloths and by sieves placed over such
cloths into the collecting trough a below. The liquid to be filtered, therefore,
enters the final filters through the hollow shaft, while it gains admission to the
preliminary filters from outside (see in particular Figs. 4 and 5). In order to
prevent the sediment contained in the compartment which happens to be upper-
most in the final filter in use, while the filter is at rest, from entering the hollow
shaft, valves or flaps v are provided, which will close of their own accord, when-
ever the corresponding compartment of the filter is situated at the top (Fig. 7).
In the drawings (Fig. 6) the final filtering drum n¹ is supposed to be in operation,
while n² is represented as being at rest. When all compartments of the former
are charged with sediment, such filter is thrown out of gear by means of a lever h,
the clutch, along with the tuber, being to this end moved to the right for such a
distance, that the orifices o¹ coincide with the orifices o2 of the filter n³, while
at the same time the pins or tappets f f 'engage with corresponding perforations
in the final filter n², so that this filter receives rotary motion from the shaft a and
tube r, and that the liquid may enter the same through the orifices o, o¹, 02, as
indicated by Fig. 8. In the meantime the filter n', being out of gear, remains
idle, and the apertures o¹ of the left side no longer coincide with the orifices o,
whereby the liquid to be filtered is debarred from entering the filter n'. Consequently
the sediment may be conveniently removed and the cleansing may now be proceeded
with. Instead of carbonic acid gas, other suitable precipitants may be introduced
between the preliminary and the final filter.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare, that what I claim
is:-
1. A rotary drum filtering apparatus comprising in its construction a preliminary
inward-flow filter adapted to conduct the liquid to a central tube or hollow shaft
connected with a carbonic acid supply pipe for precipitating the lime in the liquid,
and a supplemental outward-flow filter or filters adapted to treat the liquid dis-
charged from the preliminary filter, substantially as described.
2. In a rotary drum filtering apparatus having a preliminary filter and two or
more supplemental filters, the combination of a perforated hollow shaft a carrying
the supplemental filtering drums, with a perforated sliding tube, an adjustable
sleeve adapted to establish or interrupt communication between the said shaft
and the interior of the filtering drums, and a movable.coupling adapted to reverse
the position of the said tuber relatively to the filtering drums, substantially as
described.
3. A rotary drum filtering apparatus comprising in its construction a scrapen
or brush d kept in contact with the sieves of the filtering drum by elasticity or
other means for the purpose of removing the mud or dirt, a screw-conveyor or other
suitable means for transporting the mud thus scraped off, and a receptacle supplied
with hot water and adapted to receive the said mud, substantially as described.
4. A rotary drum filter constructed and adapted to operate as described and
illustrated by the drawings.
Dated this 14th day of June 1898
FAIRFAX AND WETTER,
Agents, 37 and 39, Essex Street, Strand, London.