Liquid purification or separation – Casing divided by membrane into sections having inlet – Each section having inlet
Reexamination Certificate
1998-07-30
2001-04-03
Drodge, Joseph W. (Department: 1723)
Liquid purification or separation
Casing divided by membrane into sections having inlet
Each section having inlet
C210S321870, C210S323200, C210S335000, C210S340000
Reexamination Certificate
active
06210576
ABSTRACT:
The invention relates to a system for cross-flow membrane filtration, having a number of membrane modules, wherein the membrane modules, lying one behind the other, are connected with each other in series (passes) for the flow-through of the retentate, and the series are parallel connected with collection lines for supplying and removing the retentate.
DESCRIPTION OF THE PRIOR ART
Membrane modules of this type are known as components of cross-flow filtration installations. Cross-flow filtration is a pressure filtration. Here, the product to be filtered flows at a predetermined speed crosswise to the direction of passage and along the surface of the filter or filtration membrane. The cross flow prevents the deposition of solids on the surfaces of the filters to a large extent and therefore allows an extended operating time without plugging of the filters.
Membrane modules of this type are often designed as so-called tube or capillary modules, wherein one or several capillary tubules or tubes are combined in a bundle-shaped unit. Depending on the type, the membrane here is attached to the inner wall or the outer wall of the tubes. In one embodiment, nineteen membrane tubules of an interior diameter of ½ inch are combined into a bundle in a module. The retentate flows simultaneously and parallel through these nineteen tubules at a predetermined pressure. After passage through the filter membranes, the permeate flows off via two connections on each membrane module.
A known system for membrane filtration, having a number of such membrane modules
1
, is shown in a lateral view in
FIG. 1
a,
and in
FIG. 1
b
in partial section along the line B—B in
FIG. 1
a.
In this case the membrane modules
1
are arranged one behind the other in five series
3
(passes) on supports
2
. Seven membrane modules
1
, lying in a vertical plane one above the other, are connected in a series by U-shaped elbows
4
in each pass
3
. The medium to be filtered is pumped in as retentate at a connector
5
in each pass
3
, and leaves the pass
3
at a connector
6
of the topmost membrane module
1
. Supply and removal of the retentate at the connectors
5
and
6
of the five passes
3
takes place via horizontally extending collection lines, not represented.
Collection lines
8
, shown in
FIG. 1
b,
are also provided for removing the permeate from connectors
7
of the membrane module
1
. A problem with these known systems resides in that on the one hand the U-shaped elbows
4
determine the vertical distances between the membrane modules
1
, but on the other hand can only be efficiently produced with tolerances of the distances of several millimeters between their connectors. Therefore the distances between the membrane modules
1
do not match the distances between the support
2
. A large production outlay results because of adjustment work on the frame of the supports
2
.
FIG. 2
illustrates a known solution of this matching problem. The distance tolerances between the membrane modules
1
and the supports
2
are evened out by placing the membrane modules
1
on flexible compensation brackets
9
. The production, mounting and adaptation of the compensation brackets
9
again results in a large labor outlay. Furthermore, the seating of the membrane modules
1
is not always secure. There is a danger of breakage in connection with modules made of plastic or ceramic material. If the distances between the supports
2
with the compensation brackets
9
are not sufficiently accurately matched, or if the axes of the modules
1
are not sufficiently parallel, leaking flange connections and damage to their seals can result. This even more so, since the number of the flange connections to be made is mostly greater than 160.
SUMMARY OF THE INVENTION
It is therefore the object of the invention to remedy the stated problems to a great extent.
In accordance with the invention, this object is attained in connection with a system of the type mentioned at the outset in that the membrane modules of each series (pass) are arranged lying horizontally next to each other in at least one plane.
The system is advantageously designed in such a way that the horizontal planes of several series (passes) of membrane modules are arranged vertically above each other, and that the collection lines for the supply and removal of the retentate of the series (passes) are vertically oriented.
In the course of this, the characteristic may arise that at least one series (pass) of membrane modules is arranged in two planes located vertically above each other, and that the connection from the lower plane to the upper plane between two membrane modules takes place by means of an obliquely extending U-shaped elbow.
In a preferred embodiment the collection lines for the supply and removal of the retentate have removal openings for collected solids (sludge).
Additional variants of the system are characterized in the claims.
In comparison with known arrangements with series of membrane modules which are arranged vertically, the system in accordance with the invention offers the additional advantage that it is possible to increase the number of modules in each series (pass) without needing additional support arms, as long as the simple support frame already has a sufficient number of reserve spaces for such additional modules.
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patent: 3734297 (1973-05-01), Windle
patent: 4016078 (1977-04-01), Clark
patent: 4080296 (1978-03-01), Clark
patent: 4732676 (1988-03-01), Molnar et al.
patent: 4988445 (1991-01-01), Fulk
patent: 5034125 (1991-07-01), Karbachsch et al.
patent: 5137631 (1992-08-01), Eckman et al.
patent: 5141640 (1992-08-01), Sasajima et al.
patent: 5470469 (1995-11-01), Eckman
patent: 75 05 931 (1975-02-01), None
patent: 0 039 583 (1981-11-01), None
patent: 0 065 070 (1982-11-01), None
patent: 1 465 971 (1977-03-01), None
patent: 96/41676 (1996-12-01), None
Bucher-Guyer AG
Burns Doane Swecker & Mathis
Drodge Joseph W.
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