BODY FOR MEMBRANE FILTERS

Abstract: The invention is characterized in that it comprises several components formed by at least two filtering elements that are coaxially coupled to one another by means of connecting elements, thereby forming an assembly with ends finishing in two respective terminal parts. Said component assembly is surrounded by a layer that has been molded thereon and which consists of fibreglass and resin. Once hardened, said layer forms the rigid, cylindrical outer surface of the body for the membrane filters. The outer surface of said body has two peripheral grooves close to the ends thereof, said grooves enabling connection of two bodies and the end heads of the filter. Said grooves may be complemented with peripheral end projections and may also be located inside said body.

Description: Different membrane filter types are already known which have a body formed for example by a spiral membrane or a microtube membrane and determining a cylinder, a shell being arranged on the periphery of said membrane in order to thus maintain the diameter of its cylindrical arrangement. This cylinder constitutes the filtering element that is housed in a rigid tube each of whose ends is provided with an end member, to these latter being fitted the corresponding caps having the fluid inlet and outlet. The membrane filters of this kind are preferentially used for filtering liquids. Since in these filters the filtering element is manufactured in a separate operation it becomes difficult to later on get it to perfectly fit into the outer tube, this possibly bringing about a defective functioning of the filter. This problem becomes more serious when the filter consists of two or more filtering elements being coaxially connected by means of connecting elements arranged between them. The following are cited as background prior art to this type of bodies for membrane filters: European Patent No. 048731-A which relates to a filter unit with end connectors for connecting a plurality of filter units, each end connector having a base with a sealing surface and a connecting portion for another end connector; and Patent WO-9820962-A1 which relates to a filtration membrane module comprising a filter housing having external connections and a compartment in which a bundle of filtration membranes are provided, the filter body being made from PVC. This invention has as its object a membrane filter body having a low manufacturing cost and comprising two or more filtering elements with the corresponding connecting elements between them and with the end members, said assembly having its periphery snugly fitted to the outer shell thus determining a notable efficiency of the filter. This membrane filter body is characterised in that said assembly being made up by the filter components is surrounded by a fibreglass and resin layer moulded on it, said layer when having hardened forming the rigid outer surface of said cylindrical body. Near each of its ends the outer surface of said cylindrical body will be preferably provided with a corresponding peripheral slot being apt to facilitate the connection between two of these bodies, as well as that of the end caps being respectively provided with the inlet and outlet for the liquid to be filtered. For those cases requiring said connections to be mechanically stronger each of the ends of the cylindrical body has been provided wit a peripheral projecting ridge next to each of said peripheral slots. For said connections the cylindrical body of the filter will in some cases be provided with only said peripheral projecting ridges. It has also been foreseen to improve said connections so that they can be apt to be fitted to commercial fittings, the peripheral slots being for such a purpose provided near the ends of the inner surface of the cylindrical body, a metallic stiffener being provided in those cases requiring the connections to be mechanically stronger. These and other characteristics will be best made apparent by the following detailed description whose understanding will be made easier by the accompanying three sheets of drawings showing some practical embodiments cited only by way of example not limiting the scope of the present invention. In the drawings: Fig. 1 illustrates in a diagrammed longitudinal section the assembly being made up by three filtering elements; Fig. 2 shows in a diagrammed longitudinal section the above-mentioned assembly being provided with the cylindrical outer shell; Fig. 3 represents the filtering body in a side view; Fig. 4 shows in a diagrammed front elevation the configuration of the connecting elements being provided between the filtering elements, and that of the end members; Figs. 5 and 6 in a diagrammed longitudinal section and in a side view respectively represent the end region of the filter body being provided with said peripheral projecting ridge and slot; Fig. 7 shows in a side view the end region of the filter body with only the peripheral projecting ridge; Fig. 8 represents in a diagrammed longitudinal section the end region of the filter body with the above-mentioned inner slot; and Fig. 9 in a side view shows the end region of the filter body as per Fig. 8. According to the drawings the membrane filter body comprises several components formed by three filtering elements 1, 2 and 3 being coaxially connected to each other by means of connecting elements 4 thus forming an assembly having each of its ends provided with an end member 5, said assembly being shown in Fig. 1. The filtering elements are formed by a spiral membrane being wrapped on a tube 6 thus forming a cylinder in its turn being wrapped in a tape 7 being wound on its periphery in order to thus maintain the cylindrical arrangement of the spiral membrane. The connecting elements 4 and the end members 5 have a circular configuration with a central orifice 8 and radial openings 9 (Fig. 4). The assembly having been made up by the above-mentioned components forms a cylinder that is surrounded by a fibreglass and resin layer 10 being moulded on said cylinder, said layer when having hardened thus forming the rigid and cylindrical outer surface of this membrane filter body, a corresponding cap (not shown) being respectively provided with the inlet and outlet for the liquids to be filtered being fitted to each of the ends of said body, the periphery of said filter body near each of its ends having been provided with a slot 11 in order to facilitate said fitting. Said layer 10 will be preferably moulded on the assembly comprising the above-mentioned components by means of winding a resin-impregnated glass filament, said winding thus determining the thickness of said layer according to the requirements to be met by the filter and above all in correspondence with its operating pressure. In this kind of membrane filters the liquid to be filtered flows in through one of the end faces of the filter body as per arrow F, and the filtered liquid flows out through the axial tube as indicated by arrow F'. For the connection of the caps to the filter bodies and between said bodies each of these latter's ends has been provided with a peripheral projecting ridge 12 next to each of the peripheral slots 11' (Figs. 5 and 6) or with only a projecting ridge 12 (Fig. 7). For said connections a peripheral slot 11" has been as well provided in the inner surface and near the ends of the filter bodies.

Claims: A membrane filter body, comprising several components formed by at least two filtering elements (1), (2) and (3) being coaxially connected to each other by means of connecting elements (4) thus forming an assembly having each of its ends provided with an end member (5), characterized in that this assembly has been made up by said components being surrounded by a fibreglass and resin layer (10) being moulded on it, said layer when having hardened thus forming the rigid and cylindrical outer surface of said membrane filter body. A membrane filter body as per claim 1, characterised in that near each of its ends its outer surface is provided with a peripheral slot (11) being apt to facilitate the connection between two bodies, as well as that of the end caps being fitted to the filter. A membrane filter body as per claim 1, characterised in that at each of its ends its outer surface has been provided with a peripheral projecting ridge (12) being apt to facilitate the connection between two bodies, as well as that of the end caps being fitted to the filter. A membrane filter body as per claim 3, characterised in that next to each of said projecting ridges (12) its outer surface has been provided with a peripheral slot (11'). A membrane filter body as per claim 1, characterised in that near each of its ends its inner surface has been provided with a peripheral slot (11") being apt to facilitate the connection between two bodies and that of the end caps.

Inventors: THOMASSEN JOHANNES A, THOMASSEN, JOHANNES A., THOMASSEN, Johannes A., Membrane ConceptsS.L.
Applicants: MEMBRANE CONCEPTS S L, MEMBRANE CONCEPTS S.L.
Application year: 2001
Main classification: B01D29
IPC codes: B01D35, B01D63, B01D65