Pipe joints or couplings – Having plural independent paths – For concentric tubes or pipes
Reexamination Certificate
1998-12-18
2001-10-16
Luu, Teri Pham (Department: 3627)
Pipe joints or couplings
Having plural independent paths
For concentric tubes or pipes
C285S123100, C285S371000
Reexamination Certificate
active
06302448
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a coupling unit for coupling two tubular membrane elements of a kind applied in membrane filter technology, which membrane elements form extensions of one another.
As is probably known, membrane filtration is a separation technique in which liquids and gasses are separated with the aid of membrane elements. Some of the substances are retained and the rest of the substances pass through the membrane. Thus, a feed stream to be purified is divided into a purified production stream and a concentrate stream.
In a known membrane filter technique a plurality of membrane elements is connected in series and placed into a tubular pressure vessel. The pressure vessel fits closely around the membrane elements, with sealing rings provided between the membrane elements and the pressure vessel. The membrane elements and the pressure vessel thus form an assembled unit.
SUMMARY OF THE INVENTION
The object of the invention is to provide a coupling unit for such membrane elements, by which means it becomes possible to couple membrane elements without being obliged to employ such a pressure vessel.
To this end the coupling unit according to the invention is characterized by a jacket piece, which is provided at both its ends with sealing surfaces intended to engage the facing ends of the membrane elements to be coupled thereto.
With the aid of the jacket piece according to the invention the membrane elements are coupled together both in the flow-technical and in the constructive sense. With low-pressure applications the above-mentioned pressure vessel may be omitted altogether. However, if a pressure vessel is employed, the membrane elements and the pressure vessel form independent parts of the installation. This provides the possibility of manufacturing the membrane elements and the pressure vessel independently of each other, using different measurements and having a free choice of material. It also allows the pressure vessel to serve as conveyor pipeline for one of the streams.
In accordance with one preferred embodiment of the coupling unit, the sealing surfaces are formed on the interior peripheral wall of the jacket piece and are designed to engage the exterior peripheral wall of the ends of the membrane elements, with the inside diameter of the jacket piece being, at least at the ends, slightly larger than the outside diameter of the ends of the engaging membrane elements.
In this embodiment the coupling unit, as it were, engages around the ends of the membrane elements to be coupled. The difference between the inside diameter of the jacket piece and the outside diameter of the ends of the membrane elements is selected such as to obtain the desired fit. For example, if a coupling has to be pull-resistant the fit will be tighter than when such a coupling is not required to be pull-resistant.
Although the ends of the jacket piece could conceivably be provided with a step-like diameter increase in order to enable them to engage around the membrane elements, constructionally it is preferred that said inside diameter of the jacket piece is the same over its total length. In this manner an uncomplicated jacket piece is obtained whose manufacture is simple.
Another embodiment provides a coupling unit whose sealing surfaces are formed on the cross-cut end surfaces of the jacket piece, and are designed to engage the facing cross-cut end walls of the membrane elements. In such a case the cross-cut end surfaces of the jacket piece and the cross-cut end walls of the membrane elements are pushed together tightly by additional means.
Irrespective of which embodiment is adopted, it is further preferred that the sealing surfaces are provided with means such as sealing rings, surface profiling, and the like, to promote the efficacy seal and/or the engagement. The sealing rings may, for example, be admitted into peripheral grooves in the jacket piece to engage appropriate surface profiling on the membrane elements. Naturally, the reverse is also possible, with sealing rings being provided on the membrane elements and the jacket piece possessing surface profiling.
As a particular form of surface profiling thread could be mentioned, by means of which the jacket piece can be screwed onto the end of the membrane elements.
One particular embodiment of the coupling unit mentioned is characterized by at least one axially extending conduit portion located in the interior of the jacket piece, designed to have its two ends communicate with corresponding flow conduits in the membrane elements. When two membrane elements are coupled with the aid of said coupling unit, the conduit portion ensures that with respect to flow, corresponding flow conduits in the various membrane elements are in communication.
In this context it is preferred that the outside diameter of the conduit portion is slightly smaller than the inside diameter of said flow conduits in the membrane elements. This allows the ends of the conduit portion to be inserted into said flow conduits to form a sealing connection between the conduit portion and said flow conduits.
In this connection it is further advantageous if the conduit portion extends in the axial direction past the ends of the jacket piece. In this manner the overlap between the conduit portion and the flow conduits suffices to minimize the possibility of leakage.
A constructionally simple embodiment of such a variant of the coupling unit may be obtained by joining the conduit to the jacket piece by means of substantially radially extending spoke portions.
As already mentioned above, it is possible with the aid of the coupling unit according to the invention, to employ coupled membrane elements in combination with a pressure vessel known as such. In such a case it is preferred to provide the exterior periphery of the jacket piece with spacer studs. With the aid of said spacer studs it becomes simple to centre the coupling unit, and accordingly, the membrane elements in the interior of the pressure vessel.
Since in such a case the pressure vessel generally also acts as conveyor pipeline for one of the streams, it is advantageous to distribute the spacer studs evenly and in the axial direction over the periphery of the jacket piece. In this way they will form no impediment to said stream.
Naturally it is also possible to have more than one conduit portion inside the jacket piece of the coupling unit. In a general one could say that the embodiment of the coupling unit strongly depends on the design of the membrane elements to be coupled.
Hereinbelow the invention will be explained in more detail with reference to the drawings which illustrate a number of embodiments of the coupling unit according to the invention.
Other objects, advantages and novel features, and further scope of applicability of the present invention will be set fourth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
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patent: 4786088 (1988-11-01), Ziu
patent: 5034125 (1991-07-01), Karachsch et al.
patent: 5141261 (1992-08-01), Ziu
patent: 5456502 (1995-10-01), Sharp
patent: 5547231 (1996-08-01), Sharp
patent: 228017 (1963-06-01), None
patent: 0 383 146 B1 (1993-12-01), None
patent: 91/14498 (1991-10-01), None
patent: 93/23152 (1993-11-01), None
De Moel Petrus Jacob
Van Der Meer Walterus Gijsbertus Joseph
Van Paassen Wilhelmus Cornelis
Luu Teri Pham
Myers Jeffrey D.
N. V. Waterleiding Friesland
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