Improvements in Filters.
Year: 1899

page_text: Date of Application, 12th Apr., 1899-Accepted, 10th June, 1899
COMPLETE SPECIFICATION.
Improvements in Filters.
I, ARTHUR ERNST KRAUSE, of 345, Fairmount Avenue, Jersey City, Hudson
County, State of New Jersey, United States of America, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
This invention relates more particularly to filters for removing oil from boiler
feed water, although it is also applicable to filters for removing sand, sediment,
and impurities generally from water, and for the filtration of sugar solutions, beer
and other fluids.
The chief objects of my invention are to provide compact filtering apparatus
containing a very large filtering surface in proportion to its size, adapted par-
ticularly for the removal of oil from feed water but likewise capable of being
employed for general filtration. Further objects are to provide an improved con-
struction and arrangement of filter bags, and to so arrange the filtering material
that all portions of the same shall be equally and highly efficient. I also provide
improved means for supporting the filter bags, maintaining passages for the un-
filtered and filtered liquids, and carrying off the filtrate. Further features of my
invention consist in providing means for preventing, so far as possible, the settling
of sediment upon the filter bags; in providing means for cleansing the filter; and
in so constructing the filter that it shall be durable, easily operated, easily cleaned,
readily taken apart and put together, and comparatively inexpensive.
According to my invention I employ one or more series of separate filter bags
which are supported upon a carrier passing through said bags and so constructed
as to afford channels or passages by which the liquid percolating through said bags
may pass away. The sides of each bag are held apart by distance or spreading
pieces or rings, the arrangement being such that all liquid passing through the
fabric composing the bag can readily pass into the aforesaid channels or passages.
The said pieces or rings also serve to secure the bags in place upon the carrier.
The bags are mutually supporting when in use, and require no internal stiffening
device to prevent them from falling over. sideways to such an extent as to interfere
with filtration.
Each series of filter bags is mounted upon a separate carrier; the said carriers
being preferably arranged parallelly about a supporting shaft, which can be turned
so as to cause the carriers to revolve around the said shaft, by which means the
filter bags may be cleaned without removing them from the filter, or in any way
disturbing their connection with the carriers.
The filtering chamber is preferably of cylindrical shape, and the unfiltered liquid
is introduced thereinto through a slot extending substantially the whole length of
said chamber and opening into the same in a tangential direction so as to cause the
liquid to circulate in the chamber. I provide at the bottom of the chamber a fin
or lip beside which is an aperture or apertures communicating with a sediment
chamber; and I provide a similar fin or lip at the top of the chamber beside which

page_text: is an aperture or apertures communicating with a scum chamber. By these means
the settling of sediment upon the filter bags is to a large extent avoided the major
portion of such sediment, and also scum, being delivered into the respective cham-
bers as the liquid washes or circulates round the filtering chamber.
In order that my invention may be clearly understood and readily carried into
effect I will proceed to describe the same more fully with reference to the accom-
panying drawings in which;-
Figure 1 is a central vertical longitudinal section of a filter constructed accord-
ing to my invention, the section being taken on the line a-a of Figure 2 looking
in the direction of the arrows; and
Figure 2 is a vertical transverse section of the filter, taken on the line b-b of
Figure 1 looking in the direction of the arrows.
Figure 3 is a detail view, drawn to an enlarged scale, of one of the filter bag
carriers with a number of bags thereon, some of which are shown in section. This
view also shows in section the header into which the filtrate from the various series
of filter bags is discharged.
Figure 4 is a vertical transverse section, drawn to the same scale as Figures 1
and 2, of this header, the section being taken on the line cc of Figure 3 looking
in the direction of the arrows.
Figure 5 is a vertical transverse section of one of the filter bag carriers, taken
on the line dd of Figure 3 looking in the direction of the arrows, the front layer
of fabric of the filter bag shown thereon being broken away to disclose one of the
distance or spreading rings within the bag.
Figure 6 is a detail central longitudinal sectional view of one of the filter bag
carriers, taken on the line e-e of Figure 7; and
Figure 7 is a transverse section taken near the discharge end of the carrier on
the line ff of Figure 6.
Figure 8 is a transverse sectional view of the filter taken on the line g-g of
Figure 1 looking in the direction of the arrows, and drawn to the same scale as
Figure 1. This view shows the rear support of the filter bag carriers, and the
bracket in which the shaft of the filter has one of its bearings.
Figures 9 to 14 inclusive are detail views of the filter bags and the parts in
proximity thereto, showing different means which may be employed for preser-
ving passages for the unfiltered and filtered liquid to and from the filtering sur-
faces; Figure 9 showing edge and sectional views of a number of filter bags, each
composed of two outer layers of cloth and a third inner layer of some fabric having
a "pile on each surface; Figure 10 being a transverse section of a filter bag
carrier, showing a face view of one of the filter bags of Figure 9, the outer layer
of fabric having been broken away to show the inner layer of "piled" fabric;
Figure 11 being a view similar to Figure 9, but showing bags which have between
them a layer of piled fabric; Figure 12 being a view similar to Figure 10, showing
a face view of one of the filter bags of Figure 11, the various layers of fabric of
this bag having been broken away to disclose the layers of piled fabric interposed
between said bag and the next succeeding bag; Figure 13 being a view similar to
Figure 9, showing external spacing rings between the filter bags; and Figure 14
being a view similar to Figure 9, showing filter bags made from a piled fabric
such as Turkish towelling.
In all the figures like reference figures are employed to designate the same or
similar parts.
1 is the main or central portion of the casing of the filter. 2 and 3 are end pieces,
the piece 3 having cored out in it a chamber 4 into which the filtrate passes, as
hereinafter described. 5 is a chamber cored out in the top of the section 1, and
may be termed a distribution chamber, since it serves to distribute the entering
liquid over substantially the whole length of the filtering chamber. It has an
opening 6 communicating with the supply pipe and a port 7, extending the whole
length of the distributing chamber, communicating with the filtering_chamber
and discharging the entering fluid tangentially thereinto as shown in Figure 2.

page_text: 8. is a supply pipe, which carries the liquid to the filter, and 9 is a discharge
pipe. The supply and discharge pipes are preferably connected by a by-pass pro-
vided with a valve 10 which is normally closed. Valves 11 and 12 are also inter-
posed between the supply and discharge pipes respectively and the filter, and these
valves are kept open while the filter is in operation.
13 is a central shaft extending from the discharge end of the filter through both
walls of the end piece 3 into and through the main or filtering chamber of the
filter, and having bearings in a bracket 14 at the opposite end of the filter, and also
in the outer wall of the end piece 3, where a stuffing box 15 is provided. This
shaft carries a plate 16 and a header 17, which together support a number of
filter bag carriers 18, upon each of which a series of disc-like filter bags 19 are
mounted.
The filter bag carriers 18 may have a spider-like or three-winged section, as
shown in Figures 2, 4, and 5, so that recesses are formed in their sides which,
with the filter bags themselves, constitute channels for the passage of the filtrate.
I may employ perforated tubes for carrying the filter bags, but I prefer the con-
struction of carrier shown since it may be cast and requires no boring or machine
work other than the screw-threading of the ends. Instead however, of having
three wings the said carriers may have only two wings; in other words, they may
consist of simple bars the width of which is about one third of their diameter.
The side recesses of these carriers are continued through their enlarged ends,
as shown at the left-hand in Figures 6 and 7, so that the filtrate may be dis-
charged into the interior of the header 17.
As well as an internal chamber, the header 17 has a hub revolubly mounted
in the inner wall of the end piece 3, and surrounded by a stuffing box. This hub
has an opening through which the shaft 13 passes, said opening being considerably
larger than the shaft, so. that the filtrate entering the interior of the header 17
passes through the opening in the hub thereof into the chamber within the end
piece 3.
A crank 22 is provided for rotating the shaft 13.
In the bottom of the main casing 1 of the filter are a series of openings 23 lead-
ing to a sediment chamber 24 cored out in the bottom of the casing 1 or otherwise
connected thereto. From this chamber sediment may be drawn, from time to time,
through a pipe 25 provided with a suitable valve 26. The pipe 25 and valve 26
may also serve as a means for emptying the main chamber of the filter. A pipe 27
having a valve 28, and connected with the filtrate chamber 4, is provided to facili-
tate the cleansing of the filter bags, as hereinafter described. At the top of the
filter there is a scum chamber 29 connected with the interior of the filter through
a passage 30. This scum chamber is provided with a gauge glass, and with a
cock 33 through which the scum may be drawn off.
As already stated and as shown in Figure 2, the water or other liquid enters
the filtering chamber in a tangential direction, and it consequently circulates with-
in the chamber in a rotary manner. Such circulation tends to prevent the collec-
tion of sediment upon the filter bags. This circulation also assists in the collection
of scum in the scum chamber 29, and in the collection of sediment in the sediment
chamber 24; for just beyond the openings 23, leading to the sediment chamber,
and just beyond the mouth of the passage 30, leading to the scum chamber, are
fins or lips 31 and 32, which intercept sediment and scum carried by the water and
direct the sediment into the sediment chamber and the scum into the scum chamber.
The filter bags 19 are each composed of two or more layers of fabric sewed,
woven or otherwise secured together at the outer edges, and having central aper-
tures in order that they may slip over the filter bag carriers 18. The bags may
be either round, as shown, square, or of any other shape desired. They may be
made of cotton twill having a coarse thread interwoven into the meshes so that
separate channels are formed for the unfiltered liquid to find its way over the
entire surface of each bag. when the bags are in place upon the carriers, as also
to form similar channels within the bags so that the filtered liquid may pass into

page_text: the side channels of the filter bag carriers. To further facilitate the passage of
the liquid through the interior of each bag the bags may be provided with internal
layers of fabric, such as that known as Turkish towelling, which has a pile on
each surface. Figures 9 and 10 illustrate this construction. The bags there shown
have each an interior layer 35 of piled fabric which keeps the outer layers of the
filter bag apart, while the spaces between the fibres of the pile permit the passage
of the filtered liquid.
Layers of piled fabric may also be interposed between the several bags, to
assist in preserving passages through which the unfiltered liquid may reach the
sides of the bags, as shown at 36 in Figures 11 and 12. In this case a finer filter-
ing cloth may be used for the bags, the interior and exterior layers of piled fabric
providing for the free passage of the liquid both to and from the filtering
surfaces.
Before placing the bags upon their carriers each bag has inserted into it two
spreading or spacing rings or washers 20 and 21, one of these rings, as 21, being
provided with projections or bosses on the side adjacent to the other ring, so as to
provide openings through which liquid within the filter bags may pass into the
side channels of the filter bag carriers. When the bags are in place on their car-
riers, the juxtaposed edges of adjacent bags are pressed together and against the
spacing rings by compression uuts 40, whereby they are securely held in place
and direct passage of unfiltered liquid between the bags into the channels of the
carriers is prevented.
The character of the fabric used in the making of the bags, and the use of
layers of piled fabric within the bags or between them, depends upon the character
of the fluid to be filtered and the impurities carried thereby. If the fluid carries
an exceedingly fine sediment, then cloth of close mesh may be required. If the
surface of the cloth is smooth it may be necessary or desirable to interpose between
the bags spacing rings 39, as shown in Figure 13.
It will be obvious from the above that in these various combinations of bags,
spacing rings, and interior and exterior layers of rough-surfaced fabric, a filtering
cloth of any degree of fineness may be used, the coarse or piled fabric acting
simply as a means for giving the liquid to be filtered and the filtrate free access
to and from the filtering surfaces, which otherwise would lie so closely together
as to prevent the passage of such liquids, or would clog up.
a
In particular cases, as in Figure 14, the bag is made of a material having
sufficiently fine body, but having also on both sides a pile, which obviates the
necessity of using interior and exterior separating cloths of piled fabric.
The use of piled fabric is not however absolutely necessary as I have found
from experiments with different kinds of liquids that even when the bags lie
close to each other and are composed of very smooth filtering material the liquid
readily finds its way over the entire filtering surface.
The operation of the filter is as follows:-
Water or other fluid entering the chamber 5 passes out through the port 7
into the main or filtering chamber of the filter, being projected in a tangential
direction. The water within this main chamber percolates through the sides of
the filtering bags into the interior thereof and then passes into the side channels
of the filter bag carrier 18, and flows into the interior of the header 17. It then
passes through the hollow hub of this header into the chamber 4 in the end piece 3,
and then out through the valve 12 of the apparatus. The sediment and impurities
carried by the liquid are caught as the latter passes through the filter bags. The
rotary circulation of the fluid within the main chamber of the filter, due to
the projection of said fluid in a tangential direction from the admission port 7,
tends to prevent the collection of sediment or scum upon the surface of the filter
bags, and to wash such impurities from said bags. The heavy impurities are car-
ried by centrifugal force to the sides and bottom of the filter, and being intercepted
by the fin 31, pass downward into the sediment chamber 24. The lighter impuri-

page_text: ties and scum pass to the top of the liquid within the filter and are intercepted
by the fin 32, passing up into the scum chamber 29.
Filtration continues in this manner until, through the collection of sediment
and impurities upon the surface and in the pores of the filter bags, the filtration
becomes too slow to be efficient. The filtering surfaces may then be cleaned by
revolving the bags by means of the crank 22. During this operation the inlet
and outlet valves 11 and 12 may be closed; and the impurities that are washed
off from the bags, which impurities pass into the sediment chamber 24, may be
drawn off by opening the cock 26. At the same time the scum within the cham-
ber 29 may be drawn off by opening the cock 33.
After the bags have been cleaned in this manner the supply and outlet valves
may be opened and filtration continued, as before. In order to facilitate rapid
cleaning of the bags, steam or any suitable fluid may be introduced into the filter
in a reverse direction through the pipe 27, the washing medium thus admitted
passing into the header 17 and thence into the interior of the filter bags and out
through their pores, thus serving to release impurities held in the pores of the
bags or upon their outer surfaces. The muddy liquid is then discharged through
the valve 26, the operation being continued until the bags are clean.
car-
When it is necessary to renew the bags, the end niece 2 at the right-hand end
of the filter is removed, together with the bracket 14 in which the right-hand end
of the shaft 13 has its bearing, and the plate 16. The filter bag carriers, with the
bags thereon, may then be removed by unscrewing them from the header 17 and
drawing them out. The filter bags may be removed from their
riers by unscrewing the nuts 40 and slipping the bags off. By a
reverse operation the filter bags may be put in place on their carriers and
the carriers reassembled in the filter. For feed water filters a number of carriers
and filter bags mounted thereon may be kept in readiness to be inserted immedi-
ately, so as to save time necessary for mounting new bags upon carriers.
My improved arrangement of the filter bags, viz., transverse bags mounted in
series without plates or frames upon carriers provided with means for carrying
off the filtrate, possesses many advangtages over the arrangement of bags employed
heretofore. A much greater amount of filtering surface in proportion to the space
occupied is obtained; the bags, being smaller, are not so likely to burst; and the
liability of the bags to rupture is further reduced owing to the fact that the pres-
sure is from the outside inward. Furthermore since the impurities are deposited
upon the outside of the bags, the bags may be more readily cleaned without re-
moving them from the filter, than is possible with the ordinary arrangement of
filter bags.
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 in a filter is:-
1. A series of separate and mutually supporting filter bags mounted transversely
upon a carrier, substantially as described.
2. A series of separate filter bags transversely mounted upon a carrier passing
through openings in such bags, and provided with means for preventing the pass-
age of unfiltered fluid between them into the filtrate, substantially as described.
3. The combination with filter bags of the kind referred to, of means substan-
tially as described for preserving passages within said bags through which fluid
may flow.
4. The combination with a series of filter bags of the kind referred to, of a car-
rier substantially as described forming with said bags channels in communication
with the interior of the bags.
5. A series of filter bags each composed of two or more layers of fabric separate
from the fabric of the adjacent bags, and provided with openings through which
a carrier passes, substantially as described.
6. A filter bag consisting of two or more layers of fabric one or more of which

page_text: have a piled surface or surfaces, said layers of fabric being secured together at
their edges and having central openings through which a filter bag carrier may
pass, substantially as described.
7. The combination with filter bags of the kind referred to, of layers of piled
fabric interposed between said filter bags, substantially as described.
8. The combination of a rotatable shaft arranged within the filtering chamber,
and filter bag carriers and bags thereon carried by said shaft and connected at one
end to a header which communicates with a suitable receptacle for the filtrate,
substantially as described.
9. The combination with a filtering chamber provided with a port through which
the fluid to be filtered enters said chamber in a tangential direction for the pur-
poses specified, of filtering-devices within said chamber and means for carrying
off the filtrate, substantially as described.
10. The combination with a filtering chamber of the kind referred to in the
preceding claim having filtering devices therein, and means for carrying off the
filtrate, of a sediment chamber and a scum chamber, and fins for deflecting the
sediment and scum into said chambers, substantially as described.
:
11. The improved filtering apparatus having its parts constructed, arranged and
combined to operate substantially as described with reference to the accompanying
drawings.
Dated this 19th day of "Annil 1800
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.