Year: 1887

page_text: Date of Application, 19th Feb., 1887
specification Accepted, 18th Feb., 1888
1, WILHELM JÄGER, Manufacturer of Könkendorf près Pritzwalk, in the Kingdom
of Prussia and 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:-
Fig. 1) shows a section through a centrifugal machine filter.
Fig. 2) is a section through a centrifugal machine filter applicable also as a rotary
pump.
Fig. 3) is a section of the filter-drum shown in Fig. 2.
Fig. 4) is a plan view of the filter-drum shown in Fig. 3.
Fig. 5) is a vertical section & Figure 6 a sectional plan of a self acting centrifugal
filter.
In practical use the centrifugal machine filters hitherto known have proved a failure.
The chief reason of this is to be found in the difficulty of constructing for them a
sufficiently porous filter, forming at the same time with mathematical exactness a
straight, hollow, concentrically rotating circular cylinder or in other words a filter
in which the outer layer of filtering material fits close against the turned, perforated,
permeable filter-drum at all points, and the inner layer of which fits against the said
outer layer and is likewise turned accurately on its inner surface.
But this centrifugal machine filter is a filter of that kind. It consists of a coarse-
grained filtering material placed in a perforated filter drum, covered on the inside
with fine metal gauze only, and operated by centrifugal power. This filter therefore
combines in itself all the above mentioned good qualities and works splendidly under
centrifugal pressure.
The difficulties to be overcome in constructing this filter are caused by the filtering-
materials being too coarse-grained. They do not rise, even if the perforated filter-
drum is covered on the inside with cloth, and do not spread themselves equally over
the surface of the drum, (as starch pulp for instance would do). When mixed with
water they let it run through at once, and settle in a ring at the bottom of the filter-
drum as soon as the latter is set in motion.
For this reason assistance must be given to the centrifugal power, and the example
of the potter and his wheel must be imitated.
There are two ways of remedying this evil.

page_text: The first is to direct a firm object, or if the centrifugal machine is revolving
rapidly, a jet of water against the filtering material that has to ascend. The other
way is, to make the thin filtering-cloth, that covers the inside of the perforated filter-
drum for this purpose, water-tight by applying to it dextrine, gum or any other
material that gradually softens and dissolves in water and disappears of itself after
having assisted the filtering material to ascend.
This latter method is however not so reliable as the other and first named mechanical
method, which is carried out in the following way.
The coarse-grained filtering material, for instance small bone charcoal, is mixed
with water and filled into the filter-drun B C D, which is open at the top, has a
perforated shell C and is covered on its inside with a fine metal-gauze F.
As soon
as the drum is set in motion a jet of water coming from a rubber hose about an inch
thick is made to play on the filtering material till the latter has reached the top D of
the filter-drum.
The water is then made to play up and down a few times on the inner layer of the
cylinder B C 1 thus formed, for the purpose of smoothening and rounding it off, as if
it were being turned on a lathe.
After the centrifugal machine filter has been made into a perfectly straight, hollow
circular cylinder, the distributor (of the fluid) is fastened to the shaft A; it consists
of the flat, round fluted plate H and the bell I.
The use of the space D E is to take up the shock of fluid coming from the
distributor. so that the fluid cannot tear or burst through the filtering-partition, and
to keep back the greater part of the dirt. From this deposit space D; E the fluid
runs along the outer or lower edge of the ring G and, passing over the inner or upper
edge of the bottom D, flows into the filtering-space BCD. By means of centrifugal
power it is forced through the filtering material, through the metal gauze F and the
holes of the shell (½, collects in the space formed by the casing and runs off through
the hole T.
As the fluid does not run out clear when the drum is first set in motion the
valve U is lifted to allow of its being conducted off separately and the outlet is
through T U V W. After a short time the valve U is shut and the filtered fluid
runs off through the pipe X.
In order to keep the fluid that has to be filtered always at the same level above the
inlet surface of the centrifugal machine filter, the flowing in of the fluid is regulated
by a self-acting regulator of the following kind.
K is the inlet-pipe, L is a valve in this pipe, which can be adjusted as desirable
by the hand-wheel M. The valve L is connected by means of rod R with the bell P,
which takes up through gutter N and pipe O the fluid that runs over the edge E out
of the filter-drum, and lets it run off through the adjustable valve Q. When the
outflow increases the bell P fills and sinks with the valve L and consequently decreases
the influx of the fluid.
S is a counter-weight against the rod R and on it are fastened the valve L and the
bell P.
Figs. 2-4 show another arrangement. The perforated filter drum, which is lined
with coarse-grained filtering material has at the bottom four pipe-shaped (tubular)
channels b, which run into a central pipe head d at the nave (hub).
This central pipe-head d is connected with the suction-pipe a for the fluid, and is
packed at the point of contact with the pipe a. The bottom of the centrifugal
machine has a raised edge c, which inclines inwardly and serves to bear the filtering-
material. It likewises serves to guide the fluid that comes rushing through the
section-pipe a and channels b, before, but not direct into, the filtering material. By
means of this contrivance the filtering material is prevented from being disturbed-
and the fluid is distributed over the whole of it. Another purpose of the edge c is
to keep the outlet openings of the pipes continually under water, for without that
arrangement the pipes would suck up air on the one side and would not form a
vacuum.
The filter-drun is covered on the inside with a fine metal gauze. If the filter-drum

page_text: is set in motion after being partly filled with water, the channels b and the whole
filter-drum act as a rotary pump that is to say, the water poured into the centrifugal
machine is distributed over the whole of its drum height, penetrates through the
filtering material and owing to the vacuum then formed sucks up a fresh quantity of
fluid out of the suction-pipe a. This fresh quantity of fluid runs through the
channels 6 into the interior of the filter-drum and pressing against the filtering
material penetrates through the latter. The purified (filtered) fluid runs off (escapes)
at D.
The filter-drum constructed as just described acts at the same time and in con-
sequence of the arrangements that are made as a regulator for the fluids that come in
to be filtered.
The more or the less the filter-drum is filled with fluid the more or the less fluid
will be sucked into the filter-drun through suction-pipe a. The reason of this is
up
that owing to the arrangements made the filter-drum acts (at the same time) as a
centrifugal-pump.
The quantity of fluid in the drum forms, in consequence of the centrifugal power,
a fluid-ring and is also almost stationary owing to the centrifugal power and to the
following quantity of fluid and if the quantity of fluid in the drum happen to be small
it takes up little space and therefore distributes itself in a comparatively thin layer
against the filtering-material that forms a ring. By means of this, the water sucked
up by the centrifugal power can run over a longer course, that is to say, almost to
the outer end of the channels b. But owing to the circumstance that this end of the
channels b is remote from the axis of the filter-drum, centrifugal power is developed
in a large measure and a large quantity of fluid flows out of the pipe a, and the
result is, that large quantities of the fluid that has to be filtered run over into the
filter-drum. But, let it be supposed, that in consequence of some occurrence, for
instance if the filtering material has got choked up by taking in too much extractable
material a larger or thicker fluid-ring has collected in the filter-drum, than the escape
of the fluid (that is to be filtered) out of the channels has approached the axis of
revolution of the filter-drum in the same measure as the thickness of the fluid-ring
has increased. In consequence of this the effective radius of the filter-drum, which
is acting as a rotary pump, is diminished, and the effect of the centrifugal power is
lessened in direct proportion to the quantity of water in the drum, and therefore the
suction-power is diminished in inverse proportion to the quantity of fluid collected in
the drum. The effect of the arrangements just described shows in what way they
act as a regulator for the fluid that has to be filtered. If there is no steam power
for driving the machine at disposal, the centrifugal machine filter may be operated
in the following way: (see Figs. 5 & 6) the fluid, conducted under pressure into the
machine for the purpose of being filtered, is made to rotate by means of turbine-like
channels fixed to the stationary plate H 1, which is not in connection with the
centrifugal machine. This rotatory motion is transmitted to the centrifugal machine
by means of catches or carriers (vanes) in the space CD E. The fluid, which is
conducted under pressure into the machine to be filtered thus transfers the power it
develops to the turbine-boxes (vanes) of the filter-drum and makes them rotate.
After having operated as a driving power, the fluid that is to be filtered is conducted
through the filtering-material in the manner already described.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed 1 declare that what I
claim is.
1) In the use of centrifugal machines as filtering contrivances a uniform distributing
of the filtering-material that covers the inner sides of the drum either by using a
filtering-cloth the pores of which are stopped up for the time being by means of
a substance easily soluble in water, or with the aid of a jet of water that operates on
the filtering-material, substantially as described.
2) In a centrifugal machine the space DCE, which is separated from the upper
part of the filter-drum and serves as a receptacle for the fluid coming out of the fluid

page_text: distributor HI in combination with the selfacting regulator S L R P, which regulates
the influx of fluid into the drum so that it does not exceed the escape of fluid out of
the drum; substantially as described.
3) The application of a centrifugal pump with rotary shell as regulator for the
filter claimed in claims 1 and 2; substantially as described.
4) In the centrifugal-machine filter claimed in claims 1 and 2, the pipe-conduit a
and channels b, which suck up the fluid that has to be filtered into the filter-drum
that is lined with filtering material, the said filter-drum being provided with a
raised edge c, which projects towards the inside of the drum and serves to bear the
filtering-material, so that by means of this arrangement the fluid that has to be filtered
and is sucked up by the pipe a must run in front of the filtering material and penetrate
it substantially as described.
5) The method of driving the centrifugal filter by the pressure of the fluid that
is to be filtered, the latter being directed under pressure, by means of curved channels
in the stationary distributing plate, against the curved vanes in the deposite-
chamber CDE of the filter drum, substantially as described.
TEL: 10
1007
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Filing Agents for the Applicant.