Year: 1886

page_text: I, GUSTAV BEHRNS, Engineer, residing in Lubeck, 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:-
My invention relates to filters for separating dust, or in general, finely com-
minuted solid matter from air, steam, water, or other fluids, and it consists in
constructing the filter out of a bag of suitable material having its open end at the
bottom, and receiving at this end the current of dust-laden air, &c., and in combining
therewith means for causing the bag to collapse at intervals, for subsequently
closing the same, and for finally reexpanding it quickly, in order to produce a back-
current of fluid through the pores of the bag and to shake it, so as to clean the bag
of adhering dust, &c. The invention also involves particular means for removing
and collecting the dust or other matter detached from the bag by the cleaning
process, and means whereby, in the case of filtration by suction, the bag is with-
drawn from the action of the suction-apparatus at the time it is cleaned.
A filter constructed according to my invention and designed to be used especially
for the filtration of dust-laden air, is represented on the annexed sheet of drawings
by Figs. 1 to 6 in an arrangement adapted for a current of air or other fluid
produced by means of a forcing-apparatus, aud by Figs. 7 to 9 in an arrangement
for a current obtained by a suction-apparatus. Fig. 1 is a front elevation of the
filter of the first arrangement, Fig. 2 à sectional view of the lower portion thereof;
Figs. 3 and 4 are side views with different position of movable parts; Fig. 5 is a
top view of the portion above the floor u and Fig. 6 a like view of the portion
below the said floor. Figs. 7 and 8 are side views of the filter of the second
arrangement with movable parts in different positions, corresponding to those of
Figs. 3 and 4; Fig. 9 is a top view. Fig. 10 shows a filtering bag of a form differing
from that of the bag in the preceding figures. Fig. 11 shows a part in detail.
The filtering-bag a, preferably made either in the form of a cylinder (Figs. 1 to 9)
or of a cone (Fig. 10), and closed at the top by a disk of wood, is fixed with its
lower border to the edge of an aperture p in the floor u, forming the top of the
chamber n through which the dust-laden air, &c. is driven into the bag by a
pressure-fan or other suitable forcing-apparatus. The bag is maintained in upright

page_text: and expanded state by means of a rope & running over two guiding-sheaves and a
weight c. The aperture p may be closed by a slide b consisting of a sheet of cloth
or other flexible material with transverse ledges, and which moves in guides close
to the underside of the floor u, and passes through a slit in the front wall of the
compartment n. This slide is connected by the two ropes h¹ to the sheaves j¹,
fixed on one axle with the sheave j, conneeted by the rope h to the weight c, and
it rests on a roller i, placed outside of the compartment n and continuously rotating
in the direction of the arrow shown in the drawing. The rope d is passed through
the slit e' (see Fig. 11) of the lever e centered at e³, and it is provided on either
side of the lever with a knot, or otherwise fastened to the same, so that, when the
lever is moved to one side, the weight c will be lifted, and the bag will collapse by
its own weight, as shown by Fig. 4, whereas, when the lever is released, the
weight c will return the same to the position of Fig. 3 and simultaneously draw
up and expand the bag.
The displacement of the lever e into the position of Fig. 4 is brought about by
an endless rope f, also passed through the slit e¹, and maintained in continuous
motion by means of a machine, and which acts on the lever by a knot or a driver g
fixed to the rope.
The said rope is at the same time made use of to keep the
roller constantly in slow rotation by being conducted downward over guiding
sheaves and passed around the sheave o, fixed on the shaft of the roller.
While
When, after the filtering operation has been going on for some time, the driver g
comes in contact with the lever e, it pushes the same into the position of Fig. 4 and
raises the weight c; the bag consequently then collapses by as much as the rope d
allows. Simultaneously a pull is thereby exercised on the part of the rope d which,
in the drawing, is on the left-hand side of the lever e, and this pull, in being
transmitted by the rope h and the sheaves j and j¹ to the ropes h, causes the slide b
to move to the left, and to close the aperture p, and therewith the bag a.
the slide is thus moved, it slips upon the roller in the direction contrary to the
rotation of the same. During the angular displacement of the lever e by the
driver g, the said driver slides along the lever until it meets with an enlargement e³
of the slit e', whereupon it slips through the same and releases the lever. The
weight c then quickly draws up and expands the bag, and thereby produces an
aspiration of fluid from the outside to the inside of the bag, and consequently a
back-current through the pores of the same. Moreover the weight being suddenly
stopped in its descent by the bag and the rope d, causes the bag to be shaken. By
the combined action of this shaking and of the back-draught the dust adhering to
the bag is detached and caused to drop on the slide b.
By the descent of the weight c the rope h becomes slack. The continuously
rotating roller may then by friction draw the slide along with it (i.e. to the right
relatively to the drawing) until the ropes h and ¹ have become taught again. The
slide then stops while the roller continues to rotate under the same. (Fig. 3 shows
the position of the slide a little before the end of its movement by the roller i, so
that the ropes h and h¹ are still somewhat slack.) By this displacement of the slide
the bag is opened again for the admission of dust-laden air or fluid while the dust
lying on the slide drops off the same in the measure as the slide, in passing over
the roller i, bends by its weight and assumes the vertical position. The dust on
leaving the slide may be collected in a suitable receptacle. In order that the bag,
on being drawn up, may be compressed as little as possible by the outward pressure,
it is provided with several light hoops.
If the filtration is to be brought about by a current produced by suction, there
has to be added to the described parts an impermeable casing k connected by a
pipe with a suction-apparatus. The communication between the casing and the
suction-apparatus requires, however, always to be stopped during the period the
filter is being cleaned, in order to bring the full pressure of the air or other liquid
into operation on the bag from the outside to the inside. For this purpose the
pipe is provided with a throttle-valve m, which is opened and closed by means of
a sheave fixed to the axle of the valve, and the rope h passed over the said

page_text: sneave and a guiding sheave 7, in combination with a rope s attached to the said
rope h and carrying a weight t.
In Fig. 7 these parts are shown in the position they occupy shortly before the
slide b is completely drawn back to open the bag. The throttle-valve is not.yet
quite open, and the part of the rope h between the weight c and the point of
attachment of the rope 8, is still slack; but the remaining part of h is held taught
by s and by the pendent weight t, so that there is friction between the rope h and
the sheave q, and that any subsequent pull exercised by the ropes h¹ on h, will open
the valve completely. By means of a stop the valve is then prevented from turning
further, whereas the rope h, if it should not have become taught upon its whole
length at the same moment, will slide along upon the sheave until complete
taughtness will have been arrived at. If now the lever e is brought into the
position of Fig. 8, the rope h operates to turn the valve m in contrary direction
until it is checked in closing position by another stop. The rope h then during its
further motion again slides on the sheave q, the weight t settles on a fixed support
(in the present case on the floor u), and the rope s becomes slack. If thereupon,
after the return of the lever e to the position of Fig. 7, and the consequent
slackening of the rope h, the slide 6 has partly reopened the bag, and taken up a
portion of the slack of the rope h, the weight t on being lifted by the rope & causes
tension in the latter and in the part of the rope h passing over the sheave q. By
its subsequent motion the rope then turns the sheave again in the direction in
which it opens the valve m.
For the filtration of air containing watery vapour, it is advisable to construct the
casing of a material which is a bad conductor of heat, for the purpose of
preventing a condensation of the vapour inside of the same.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. A filtering apparatus consisting of a bag having its open end at the bottom,
and means for creating a current of the fluid to be filtered into and through the
bag, in combination with means for keeping the bag expanded, for allowing it to
collapse at intervals and closing it, and for thereupon reexpanding and finally
reopening the same, substantially as and for the purpose described.
2. A filtering apparatus consisting of a bag having its open end at the bottom
and enclosed in a casing connected to a suction-apparatus adapted to draw the
fluid to be filtered through the bag into the casing, in combination with means for
keeping the bag expanded, for allowing it to collapse at intervals, for closing it
and simultaneously stopping the communication of the casing with the suction-
apparatus, and for thereupon reexpanding and finally reopening the bag, and also
reestablishing communication with the suction-apparatus, substantially as and for
the purpose specified.
3. The combination, with the bag a fixed with its lower open end to an aperture p
in the top of a compartment n, and means for creating a current of the fluid to be
filtered from the compartment n into and through the bag, of a rope & running over
guiding sheaves and attached with its ends respectively to the bag a and a weight c,
a lever e connected to the rope d and having a slit e¹ with enlargement e³ through
which passes the endless rope f provided with driver g, and a slide b resting on the
continuously rotating roller i and connected by the ropes h and h¹ to the weight c,
substantially as and for the purpose set forth.
4. The combination, with the bag a fixed with its lower open end to an aperture p
in the top of a compartment n, and enclosed in a casing k connected by a pipe / to
a suction-apparatus, of a rope & running over guiding-sheaves and attached with
its ends respectively to the bag and a weight c, a lever c connected to the rope d
and having a slit e¹ with enlargement es through which passes the endless rope f
provided with driver g, a slide b resting on the continuously rotating roller i and
connected by the ropes h and h¹ to the weight c, a throttle-valve m in pipe

page_text: carrying the sheave q over which and a guiding pulley is passed the rope h, and
the rope 8 attached to rope h and carrying the weight t, substantially as and for the
purpose described.
5. The combination, with the bag a fixed with its lower open end to an aperture p
in the top of a compartiment n, means for creating a current of fluid from the said
compartment into and through the bag, for keeping the bag expanded, for allowing
it to collapse and for reexpanding it, of a slide b consisting of a sheet of flexible
material with transverse ledges, a continuously rotating roller i placed outside of
the compartment n and supporting the slide b, and means for drawing the said
slide under the aperture p when the bag collapses, substantially as and for the
purpose set forth.