WO2005043691A1

WO2005043691A1 - Sealed passage element for conduction means, such as electric cables or suchlike, and relative sealing method

Info

Publication number: WO2005043691A1
Application number: PCT/IB2004/003098
Authority: WO
Inventors: Augusto Brambilla
Original assignee: Terrestrial Holding B.V.
Priority date: 2003-10-29
Filing date: 2004-09-23
Publication date: 2005-05-12
Also published as: ITUD20030214A1

Abstract

Sealed passage element (10) for conduction members (15), such as electric cables or otherwise, and relative sealing method. The sealed passage element (10) comprises a tubular body (16) in a through cavity (19) in which the conduction members (15) are arranged longitudinally, and sealing elements (17) arranged in the through cavity (19), in order to partly drown the conduction members (15) and seal them inside the through cavity (19). The tubular body (16) is provided inside with a seating (20) communicating with the through cavity (19) which guarantees the anchorage of the sealing elements (17) to the tubular body (16).

Description

"SEALED PASSAGE ELEMENT FOR CONDUCTION MEANS, SUCH AS

ELECTRIC CABLES OR SUCHLIKE, AND RELATIVE SEALING METHOD" * * * * * FIELD OF THE INVENTION The present invention concerns a sealed passage element for conduction means, such as electric cables or suchlike, which is able to allow the latter to pass between two insulated environments separated by a dividing wall, without the gases present in one environment being able to enter into the other. The element according to the present invention also allows to keep the two environments perfectly sealed, even when there are considerable differences in temperature, and is applied particularly in the chemical industry, on anti-deflagrating electric motors, in research laboratories or other places where it is necessary to have conditions of maximum safety and insulation between insulated environments. To be more exact, the present invention concerns a sealed passage element consisting substantially of a tubular body inside which a sealing resin is arranged, in which the conduction means are partly drowned. BACKGROUND OF THE INVENTION In order to hermetically insulate a room or an environment in which gases, substances or microorganisms that are dangerous to human beings may be present, for example in the chemical industry, in biological research laboratories or other, it is known that it is also necessary to seal perfectly the passages through which the conduction means, such as electric cables or suchlike, pass from one environment to the other. This need to hermetically insulate a determinate environment exists also in lighting apparatuses, such as for example fluorescent or electroluminescent lamps or suchlike, wherein it is required to insulate the luminous compartment from the compartment where the electronic components are arranged. A sealed passage element is known which comprises a tubular body through which such conduction means are able to pass and which is necessarily filled with a sealing resin in order to drown such conduction means. The resin, adhering to the inner surface of the tubular body, in this way creates a mass that is interposed between the conduction means and the tubular body, thus sealing the passage. Sealed passage elements of a known type have the disadvantage, however, that they do not guarantee a perfect seal when there are significant decreases in temperature. In fact, with very low temperatures, the resin is subjected to structural contractions which reduce the volume thereof, so that it detaches from the inner surface of the tubular body. This disadvantage causes through fissures to form between the resin and the tubular body, thus putting the two adjacent environments into communication, with the risk of contamination, pollution, explosion, damage to the structures or the workers, and also changes in the results obtained in any analyses carried out. One purpose of the present invention is to achieve a sealed passage element for conduction means between two separate environments, which seals the conduction means and at the same time guarantees an optimum and constant insulation of the two environments, substantially under any operating condition, even when there are differences in temperature . Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages. SUMMARY OF THE INVENTION The present invention is set forth and characterized in the main claims, whiXe the dependent claims describe other characteristics of the present invention or variants to the main inventive idea. In accordance with the above purpose, a sealed passage element for conduction means, such as for example electric cables or suchlike, according to the present invention comprises a tubular body able to be interposed between two separate environments and inside which the conduction means are able to be arranged longitudinally, and sealing means able to be arranged inside the tubular body, in order to partly drown the conduction means, sealing them inside the tubular body, and to insulate the two separate environments from each other. According to a characteristic feature of the present invention, the tubuILar body is provided inside with at least an anchoring seating for the sealing means. To be more exact, the anchoring seating comprises at least an anchoring surface arranged angled by an angle , more than 90°, with respect to the generatrix of the inner surface of the tubular body. In this way, when -the sealing means are arranged inside the tubular body, they penetrate inside the anchoring seating and adhere to the aforesaid anchoring surface. Consequently, a possible structural shrinkage of the sealing means entails an increase in their adherence against said anchoring surface. In this way we avoid the formation of longitudinal fissures between the sealing means and the inner surface of the tubular body. Thus the two environments are maintained permanently insulated substantially under any operating condition, even when the temperature suffers a significant reduction and the sealing means reduce their volume. Advantageously, the tubular body is made of metal and the sealing means consist of a resin of a known type, for example polyurethane and/or epoxy, with two components. BRIEF DESCRIPTION OF THE DRAWINGS These and other characteristics of the present invention will become apparent from the following description of some preferential forms of embodiment, given as a non- restrictive example, with reference to the attached drawings wherein:

- fig. 1 is a section view of a sealed passage element according to the present invention;

- figs. 2a-2n show some variants of the sealed passage element in fig. 1 DETAILED DESCRIPTION OF SOME PREFERENTIAL FORMS OF EMBODIMENT With reference to fig. 1, a passage element 10 according to the present invention is able to be arranged in a through hole 14 of a dividing wall 11 which separates two insulated environments 12 and 13. The passage element 10 comprises a tubular body 16, made of metal, provided with a central through hole 19, inside which a bundle of electric cables 15 can pass from one to the other of the environments 12 and 13. The tubular body 16 is attached inside the through hole 14, for example by means of a threading. The tubular body 16 comprises an inner circumferential seating 20 open towards the central through hole 19. Advantageously the inner circumferential seating 20 is shaped so as to define at least an anchoring surface 21. After arranging the bundle of electric cables 15 in the central through hole 19, the latter and the inner circumferential seating 20 are filled with a sealing resin 17, of a known type, so that the latter fills all the space inside the tubular body 16 and perfectly contacts the entire cylindrical surface of the central through hole 19, and partly drowns the electric cables 15. The anchoring surface 21 is inclined with respect to the generatrix of the cylindrical surface of the central through hole 19 by an angle a of more than 90°, for example about 135°, so that, n the event of structural contraction of the sealing resin 17, for example due to a significant reduction in temperature (condition shown by the line of dashes in fig. 1), the anchoring surface 21 can contrast said contraction along its whole circumference, thus constantly guaranteeing the adherence of the sealing resin 17, for example against a part of the tubular body 16. In this way, the electric cables 15 are always sealed and the insulation between the two environments 12 and 13 is constantly guaranteed, under any operating condition and at any temperature whatsoever. While the characteristic expressed above must always be taken into account, the inner circumferential seating 20 can have any shape whatsoever. Figs. 2a to 2n show, as an example, some of the preferential forms of the inner circumferential seating 20. As can be seen, every circumferential seating 20 has one or more anchoring walls 21 with sizes and arrangements, and also angles, that are different from the seating previously described and shown in fig. 1. It is clear, however, that modifications and/or additions of parts may be made to the passage element 10 as described heretofore, without departing from the field and scope of the present invention. It is also clear that, although the present invention has been described with reference to specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of sealed passage element for conduction means such as electric cables or suchlike, all of which shall come within the field and scope of the present invention.

Claims

1. Sealed passage element for conduction means (15) comprising a tubular body (16), disposed in a through cavity (19), in which said conduction means (15) are able to be arranged longitudinally, and sealing means (17) able to be arranged in said through cavity (19), in order to partly drown said conduction means (15) and seal them inside said through cavity (19), characterized in that said tubular body (16) is provided inside with a seating (20) communicating with said through cavity (19) and able to guarantee the anchorage of said sealing means (17) to said tubular body (16).

2. Element as in claim 1, characterized in that said seating (20) is provided with at least an anchoring surface (21) which forms an angle (α) of more than 90° with respect to the generatrix of the inner surface of said through cavity ( 19) .

3. Element as in claim 2, characterized in that said angle ( ) is about 135°.

4. Element as in any claim hereinbefore, characterized in that said seating (20) is circumferential.

5. Method to seal a passage element for conduction means (15) provided with a tubular body (16) inside which said conduction means ( 15 ) are able to be arranged longitudinally, and sealing means (17), characterized in that it comprises at least a first step of making an anchoring circumferential seating (20) inside said tubular body (16), and a second step of depositing said sealing means (17) inside said circumferential seating (20).