KARLSSON, Anders (Alamedan 23, Karlskrona, S-371 31, SE)
1. A sealing system for cable entries or pipe penetrations, comprising
- a compressible body (2) with an radially outer surface having a shape matching the inner dimensions of an opening in a wall and an inner surface having a shape matching a cable or pipe (26), or a seal insert,
- first (6, 8) and second (10, 12) fittings on either side of the axial ends of the compressible body (2), sandwiching the compressible body (2) between each other, adapted to transfer and distribute a compression force to the ends of the compressible body (2),
- compression means (14), adapted to urge the first fittings (6, 8) towards the second fittings (10, 12), characterized in thai the sealing system comprises a removable sleeve (18, 20) adapted to tightly encircle the radially outer surface of the compressible body on one side of the opening in the structure (24).
2. The sealing system of claim 1, wherein the sleeve comprises two interconnecting parts, releasably connected to each other.
3. The sealing system of claim 2, wherein the interconnecting parts are connected by means of a tongue and groove arrangement.
4. The sealing system of any preceding claim, wherein the interconnecting parts are hingedly connected to each other at one end.
5. The sealing system of any one of claims 2-4, wherein the interconnecting parts interconnects with some clearance, such that they may be assembled manually.
6. The sealing system of any preceding claim, wherein the interconnecting ends of the interconnecting parts comprise overlapping holes, such that locking pins may be used for assembly.
7. The sealing system of any preceding claim, wherein a seal insert having an inner diameter being adapted to a particular diameter of a cable or pipe is arranged in the compressible body.
8. The sealing system of any preceding claim, wherein the inner periphery of the sleeve is provided with peelablc sheets, so that the sleeve may be adapted to receive cables or pipes of various diameters.
9. The sealing system of any preceding claim, wherein the sleeve may be positioned on either side of the wall relative to one specific position of the sealing system.
10. A method for mounting a sealing system of any preceding claim, comprising the steps of :
- arranging a compressible body (2) with an radially outer surface having a shape matching the inner dimensions of an opening in a wall and an inner surface having a shape matching a cable or pipe (26), or a seal insert, around a cable or pipe, - arranging first (6, 8) and second (10, 12) fittings on either side of the axial ends of the compressible body (2), sandwiching the compressible body (2) between each other, adapted to transfer and distribute a compression force to the ends of the compressible body (2),
- arranging compression means (14), adapted to urge the first fittings (6, 8) towards the second fittings (10, 12),
- arranging a removable two-piece sleeve (18, 20) adapted to tightly encircle the radially outer surface of the compressible body on one side of the opening in the structure (24), and
- tightening the compression means.
Technical Field The present invention relates to a sealing system, for use in cable entries, pipe penetrations.
Sealing systems of the above kind are widely used today, for sealing of cables entries, pipe penetrations etc. Application areas include cabinets, technical shelters, junction boxes etc in different industrial environments, such as automotive, telecom, power generation etc.
The sealing systems are adapted to prevent ingress of fluids and moisture, as well as dust or pests, such as rodents and termites. The sealing systems may be adapted to receive cables for telecommunication, electricity, or pipes for gas or liquids.
During the construction of a new site, e.g. a technical shelter, there are several sealing systems available for use. However, when improving/repairing/substituting the sealing system of an existing technical shelter there are additional issues to consider. If the technical shelter is in use, it might be unacceptable to disrupt the traffic in the telecommunication cable.
Present sealing systems have been attached to the wall, generally a plate being a part of the technical shelter etc, by means of welding, screw joints, rivets etc. However, none of the above methods of attachment are applicable without jeopardizing the function of the cable. Also, any cutting, drilling or other machining work involves the risk of contaminating the working area, which is inappropriate in many environments.
Summary of the Invention
It is an object of the present invention to provide a sealing system particularly suited for sealing cable or pipe transits in thin-walled structures. It is another object of the present invention to provide a sealing system particularly suited for retrofitting to cables and pipes of various diameters.
According to the invention a sealing system is provided. The sealing system comprises a compressible body, having a diameter being slightly smaller than the diameter of opening in which the system is to be applied, and an axial dimension
(length) being greater than the extension (length) of said opening. The extension of said opening is generally the thickness of the wall or partition in which the opening is arranged. The compressible body has a through hole dimensioned to receive a cable or pipe, or a seal insert adapted to receive a cable or pipe. Fittings surrounds the axial ends of the compressible body and are adapted to transfer and distribute compression from compression means to the compressible body.
The compressible body also has through holes through which compression means, such as screws, arc led. The compression means are used for pulling the fittings towards each other, thereby compressing the compressible body. As the compressible body is compressed axial Iy, it will expand radially, inwards and outwards. This expansion will ensure sealing towards the cable/pipe and fixation to the opening to which the system is applied.
However, when said sealing system is arranged in a thin-walled structure, such as a sheet-metai structure, with a thickness considerably smaller than the axial length of the compressible body, adequate sealing and fixing properties cannot be achieved since the opening does not provide sufficient contact surface for the sealing system.
To this end the system is provided with a sleeve with the same inner diameter as the outer diameter of the compressible body, and an axial length such as to provide a sufficient envelope surface for the sealing system to operate properly. The sleeve serves two main purposes: providing sufficient envelope surface for ensuring proper function of the sealing systems sealing capabilities, absorb axial loads transferred through the cables/pipes.
The compressible body, any seal insert, the fittings, and the sleeve are partitioned in an axial direction, generally comprising two parts. The two parts of the sleeve are releasable connected to each other. In this way each part of the sealing system can be arranged around the cable or pipe without being thread over one end of the cable a pipe, i.e. the cable or pipe can remain connected and operational during the mounting of the inventive sealing system.
According to one or more embodiments the two parts of the sleeve may have interconnecting tongues and grooves extending in an axial direction, such that the two parts are interconnected by sliding the one into the other. The two parts may be identical, each having one tongue and one groove. This construction is efficient during manufacturing and also beneficial for the person doing the assembly, in that there is no need to store more than one type of sleeve (in each size category).
According to one or more embodiments the sleeve parts may be hingedly connected to each other at one end, and in one or several embodiments one or both ends of each sleeve part may have holes, such that the holes of the sleeve parts overlap in the assembled state. In this way locking pins may be used to effect the assembly. According to one or more embodiments the sealing system is adapted for use on thin-walled structures.
According to one embodiment a seal insert may arranged in the through hole of the compressible body. By using a seal insert, the compressible body may be optimized for its purpose, while the seal insert is optimized for sealing towards the cable/pipe. Also, the same sealing system becomes more versatile when various seal inserts can be used for the same compressible body.
The seal insert may be an insert comprising several peelablc layers of material, such as to be able to conform to various cable/pipe dimensions. This type of seal insert provides the most flexible solution. The function of the seal insert with peelablc layers of material is thoroughly described in several applications. Also, the seal insert does not have to have a circular cross section, and several seal inserts may be used in combination, which in an assembled state takes up the opening in the compressible body. The modules used are preferably adaptable to cables of various dimensions, by means of peelable sheets. The sheets are held together by an adhesive effect. The adhesive effect is strong enough to normally keep the sheets together, but not stronger than making it possible to peel off a separate sheet by hand.
For a detailed description of seal inserts please refer to WO04/112211 or WO03/ 104701 where the relevant type of seal insert is disclosed. The construction and alternatives described therein, in relation to seal inserts with peelablc layers, is considered as forming a part of this application and is hereby incorporated by reference. According to one or more embodiments, the inner periphery of the sleeve parts is provided with peelable sheets, such that the inner diameter of the sleeve can be varied to accommodate compressible bodies of various dimensions.
The invention also relates to a method of mounting said sealing system, according to claim 10. Note that the method steps of claim 10, illustrated in Fig. 10, are not necessarily executed in the stated order.
Brief Description of the Drawings
Fig. 1 is a cross sectional view of a sealing system first embodiment of the invention, arranged in an opening in a structure.
Fig. 2 is a cross section of the sealing system of Fig. 1, in a compressed state.
Fig. 3 is a cross sectional view of a sealing system second embodiment of the invention, arranged in an opening in a structure.
Fig. 4 is a cross section of the sealing system of Fig. 3, in a compressed state. Figs. 5-9 illustrate some embodiments of the sleeve of the inventive sealing system.
Fig, 10 is a flow chart for an inventive method.
Description of Embodiments The sealing system 1 of Fig. 1 comprises a compressible body 2, having a through hole 4 dimensioned to receive a cable or pipe (not shown), or a seal insert 5 adapted to receive a cable or pipe. Fittings 6, 8, 10, 12 surrounds the axial ends of the compressible body 2 and are adapted to transfer and distribute compression from compression means 14 to the compressible body 2. It should be noted that the compressible body 2, or the seal insert 5, may have one, or several, through holes filled with a rubber core blank instead of with a cable or pipe. If the hole is needed for a cable or pipe at a later time, the blank may be removed. With one exception the reference numbers have only been included in Fig. 1 (of Figs. 1-4), and it is considered obvious to identify components of Figs. 2-4 from the numbering of Fig. 1. Holes (not shown) extend through the compressible body 2, and the compression means 14, in the form of screws extend through the holes, interconnecting the fittings 6, 10 and 8, 12, respectively. At one end each screw is threaded into the fitting. Tightening of the screws will pull opposing fittings 6-12 towards each other, thereby compressing the compressible body. In this context it should be noted that the compression means 14 could also comprise a screw and nut, or any other type of suitable compression means 14
Prior to compressing the compressible body 2 a sleeve, comprising two parts 18, 20 releasabiy interlocked to each other, is arranged tightly around the compressible body 2, see also Figs. 5-9. In the embodiment of Fig. 1 the sleeve is generally adapted to abut one side of the structure 24 with one end surface, and be basically flush with the compressible body with the other end surface.
Figs. 1-4 illustrate the above system 1 arranged in an opening 22 in a structure having a thin wall 24, "Thin" refers to a comparison with the axial extension, length, of the sealing system 1 , The axial direction refers to a direction along the axis of symmetry of the compressible body 2, and the radial direction is orthogonal to the axial direction.
In the system of Figs. 3 and 4, the sleeve 18, 20 is arranged on one side of the opening 22 in the thin wall 24, abutting the wall, while the fittings 8, 10 abuts the wall 24 on the opposing side. The screws 14 extend into the fittings 12, 14 where they cooperate with an internal thread. The internal thread could be replaced by a nut. In Figs. 1 and 2 on the other hand, the sleeve 18 and the fittings 8, 10 arc arranged on the same side of the wall 24.
As indicated in Figs. 1-4 the entire system is partitioned in an axial direction, such that it can be arranged around an existing cable 26 in an existing opening 22. Figs. 2 and 4 illustrate the systems of Figs. 1 and 2, respectively, after tightening of the screws, i.e. after compression of the compressible body 2. As the compressible body 2 is compressed axially, it will expand radially, inwards and outwards. This expansion will ensure sealing towards the cable/pipe 26, via the seal insert 5 (when available) and fixation to the opening 22 to which the system is applied. The sleeve 18, 20 will ensure that the adequate portion of the compressible body 2 expands. It should be noted that the size of the bulge 3 created as the compressible body expands may be exaggerated in Figs. 2 and 4. Further, it is apparent from the embodiment of Fig. 2 that the compressible body will provide a seal of the opening 22, but the same holds for the embodiment of Fig. 4, where the compressible body 2 will bulge to seal the opening 22 adequately. According to one embodiment the sealing system thus enables the sleeve to be positioned on either side of the wall, relative to one specific position of the sealing system, as described above in relation to Figs. 1-4.
To ensure flexibility in relation to various diameter of the cables and/or openings 22 either or both of the outer circumferential surface of the compressible body, or the inner circumferential surface of the sleeve parts may be provided with a peelable structure, similar to the peelable structure of the seal insert 5.
The sleeve parts are preferably formed by extrusion and have therefore a form that is suitable for this, including a certain thickness of the material. Also, it is beneficial if the two parts of the sleeve are identical, such that they can be extruded in the same process, cut to the appropriate length, and interconnected. It should be noted that other methods of forming the sleeve parts are contemplated, such as moulding.
The compressible body is generally made of rubber, or other elastomeric material. The compressible body may comprise more than one material, for achieving a specific purpose, such as a metallic mesh for achieving electrical shielding, or a metallic foil to achieve potential equalization. The metallic mesh may be formed of conductive
rubber. The fittings need to be rigid enough to transfer and distribute the compression force from the tightening of the screws to the compressible body 2, examples of materials include steel, aluminium, rigid plastics, rigid composits, etc. The scat insert is generally made of rubber or other polymer material. It needs some flexibility to ensure proper sealing properties and it can be tailor-made for a specific purpose, in the same way as the compressible body.
Figs. 5-9 illustrate various alternatives for the sleeve parts 18, 20, the common feature being that it is possible to arrange the resulting sleeve around a cable without slipping it over an end of the cable. Each figure illustrates a front view and a side view of the specific embodiment of the sleeve. The sealing system is thus optimized for retrofitting to existing cable entries, pipe penetrations and the like, where disconnection of the cable/pipe is not a desired alternative. The sleeve, irrespective of embodiment, should be able to withstand the forces exerted by radial expansion of the compressible body 2. The sleeve parts are preferably formed in such a way that there is some clearance in the interconnection between the parts. This means that the parts may be assembled easily, and without any tools. As the compressible body 2 is compressed, the sleeve parts will be pressed outwardly, such that the frictional forces will realize locking between the parts in an axial direction, and the cooperating tongue 28 and groove 30 will realize locking between the parts 18 and 20 in a radial direction. From the drawings it should be obvious that the phrase "tongue and groove" may be interpreted to include any similar arrangement providing an interlock between the two parts of the sleeve.
Cable has been mentioned as an example around which the sealing system is applied, but it could as well be a pipe, or a conductor of fluids or electricity with another cross sectional shape, such as a busbar. This means that even if the inner circumference of the through hole of the compressible body 2 is illustrated as being circular in cross section, it may as well have any other shape, such as oblong, rectangular, square etc, to match the shape of existing and future pipes/cables and seal inserts.
It should also be obvious for the skilled person that the term "thin-walled structure" does not limit the invention to use in walls only, rather it can be used in any partition of a structure, such as a wall, a roof a floor etc. Also, the term "thin" in "thin- walled" generally cannot be defined quantitatively. In most foreseeable applications it relates to sheet-metal structures, or similar structures of plastic, but for this application the wall is thin if it does not provide adequate envelope surface for the seal system to operate properly. That is, "thin" is not only dependent on the thickness of the wall, but
also the axial length of the sealing system. As a very approximate number it is considered that at least 80 % of the axial length of the compressible body should be covered, on the outside, by a rigid contact surface. If the opening in the wall does not provide this, the inventive split sleeve may be used. It should be noted that the amount of contact surface required also depends on the rubber used in the sealing system, the level of sealing etc, which is why it is difficult to mention an exact number.