NO20171464A1 - System and method for attaching wires - Google Patents

Abstract

System for fixing one or more wires (5), where the system comprises a clamp (10, 40A, 40B, 30, 60) adapted to be fixed to a substrate (70), and one or more flexible filling elements (1). The flexible filling element (1) is designed to fill a part of a cavity formed between a wire (5) and the clamp (10, 40A, 40B, 30, 60), between several wires (5) and/or between one or several wires (5) and the substrate (70). The flexible filler element (1) is further arranged to apply to the wire (5) a force component (F) in the radial direction of the wire (5) when the flexible filler element (1) is subjected to an elastic deformation when the clamp (10, 40A, 40B, 30, 60) is in an active position.

Description

SYSTEM AND PROCEDURE FOR FIXING WIRES

The invention relates to a system for fixing one or more wires against axial movement/stretching, more specifically a system comprising a flexible element arranged to exert a radial force against a wire and a cable clamp. The invention also relates to a method for securing one or more wires in a clamp.

Background for the invention

Wires and cables designed for current and fluid are usually fixed using various types of cable clamps, cable clamps and cable rails.

In what follows, the term wire is used as a common term for wires and cables equipped with a tubular core or a core. The term clamp is used as a common term for cable clamps and cable clamps. Rail is used as a term for a cable rail, a bracket or another device designed for attaching a wire or a clamp.

The clamp can completely or partially enclose the wire. The clamp can be divisible and can be placed from an inactive position to an active position. In the inactive position, the wire is not attached. In the active position, the cable is fixed in the clamp itself or clamped firmly to a surface, for example a rail. The bracket can be attached to the substrate using a screw connection or other known method.

The axial length of the clamp can vary. The clamp is often made of plastic or metal, where a metal clamp is often provided with a rubber or plastic surface designed to provide a friction surface between the wire and the clamp. Rubber and plastic are also insulating against short circuits.

A current-carrying wire of known technique may comprise a current-carrying core of metal surrounded by an insulating material, for example plastic or rubber. It is known in the art that a current-carrying wire can generate heat and that metal expands when heat is applied. The current-carrying wire can thereby have a certain variation in its diameter and length, depending on the voltage and amperage in the wire. A wire with a large diameter and a large amount of current changes more than a small wire with a small amount of current. A varying power flow in a current-carrying line element is typical for installations in a wind turbine and in a power plant. Subsequent variation in the diameter of the wire element can have a loosening effect on a pinched wire element. A similar loosening effect can occur for lines containing a hot fluid, for example hydraulic oil.

It is known in the art that the friction between the wire and the clamp can be reduced when heat develops in the wire. In some cases, the heat generation can become so high that the outer surface of the cable's insulating material becomes plastic and smooth so that the cable can slide in the clip. Correspondingly, a varying diameter created by a varying power transmission will help to reduce friction. The problem is greatest for cables with a large diameter which are arranged vertically, for example in a wind turbine or in a power plant, where the vertical part of the cable can weigh several hundred kilograms. A live wire that slips is potentially very dangerous and can ultimately cause damage to both installations and personnel. This applies especially if the line carries a high-voltage current.

While thick wires are arranged individually to ensure adequate fastening, thin wires can be arranged in a plurality. A clip according to known technology can typically comprise 3 wires in so-called trefoil, 4 wires in phase 0 (TNC) formation or 6 wires in 2 x trefoil, where the 4 or 6 wires are arranged in pairs in height. Such a paired device, however, provides a limited contact surface between the cable elements and the cable clamp, which increases the risk that the cable may slip. Within the field, it is therefore preferred to arrange a maximum of 3 wires in one clamp in a trefoil, as described. For better use of space, however, it is desirable to have a clamp that includes 4 or 6 wires arranged in pairs, and where the 4 or 6 wires arranged in pairs have a fastening that is at least as good as for 3 wires laid in a trefoil.

On a round single wire, a circular clamp will have the best holding effect, but such clamps entail an investment in tools and place great demands on fit. In the same way, clamps that are supposed to hold several wires will make it difficult to wrap the wires tightly so that they are held in position when the wire is stretched.

Known technique

Wires can be attached individually to a structure or in a cable tray. Small cables are usually stripped, while different types of clamps are used for large cables.

Patent document NO 333025 describes a device for fixing a wire, where the wire is fixed inside a polygonal profile.

Patent document NO 317144 describes a device in the form of a clamp for clamping one or more elongated objects, where the clamp comprises a load-bearing assembly which is designed to be connected to a substrate.

Patent document NO 20032124 describes a cableway/armature rail consisting of an upwardly open, elongated trough-like body comprising a hole system in the form of rows of holes or perforations, in which body cables, pipes or the like can be placed which can be clamped to the body using pipe clamps or the like.

The purpose of the invention is to remedy or to reduce at least one of the disadvantages of known technology, or at least to provide a useful alternative to known technology.

The purpose is achieved by the features indicated in the description below and in the subsequent patent claims.

The invention is defined by the independent patent claims. The independent claims define advantageous embodiments of the invention.

General description of the invention

In a first aspect, the invention relates to a system for fixing one or more wires, where the system comprises a clamp designed to be fixed to a substrate, and one or more flexible filling elements. The flexible filling element is adapted to fill a part of a cavity formed between a wire and the clamp, between several wires and/or between one or wires and the substrate. The flexible filler element is further adapted to apply to the wire a force component in the radial direction of the wire when the flexible filler element is subjected to an elastic deformation when the clip is in an operative position.

The flexible filling element will be referred to below as a filling element. The substrate can be a rail designed for the screwable attachment of one or more clamps. The brace can be fully or partially enveloping. When using a partially enclosing clamp, for example a U-clamp, the cable can rest against the substrate. When using an enclosing clamp, a part of the clamp can be arranged between the wire and the substrate.

When a wire with a circular cross-section is arranged in a polygonal cable clamp, cavities are created between the wire and the clamp. Correspondingly, cavities are formed between wires which are arranged in pairs or triangularly. The size and number of the cavities depends on the number of wires, how the wires are arranged, the cross-section of the wires and the shape of the clamp.

For example, a wire arranged in a square or square bracket will create four cavities, one in each corner of the bracket. In order to increase the contact surface between the wire and the clamp, and thereby increase the friction, it is known to use clamps with more than four surfaces and/or with a curved surface.

Four wires of equal cross-section arranged squarely in a square cable clamp form one cavity in the center of the four wires and eight cavities between the wires and the clamp.

Three wires of equal cross-section arranged triangularly (trefoil) in a triangular clamp, forming one cavity in the center of the three wires and six cavities between the wires and the clamp. The centered cavity in a triangular arrangement is smaller than the centered cavity in a square arrangement when the diameters of the wires are equal.

When the cross-section of a wire changes, the surface pressure between the wire and the clamp and/or the substrate also changes. It is therefore important that the clamp is adapted to the wire so that the clamp exerts a clamping force against the wire. A metal clamp has limited elasticity, and a correct clamping force can therefore be difficult to achieve. The invention solves this problem by placing the filler element between several wires and/or between at least one wire and the clamp, so that the filler element functions as an internal spring that exerts a force against the wires.

By arranging the filling element in one or more of said cavities, as the invention describes, an extra, and essentially a constant pretension between the wires and the clamp is provided. This preload is designed to provide increased friction between the wires and between the wires and the clamp. When a wire expands, the filler element will be compressed perpendicular to the center axis of the filler element. When a wire shrinks, the filler element will expand perpendicularly to the center axis of the filler element.

The filling element is advantageously made of an elastic material which maintains its elasticity at varying temperatures. The material can also be oil and chemical resistant, fire retardant and weather resistant. Examples of such a material are ethylene-propylene rubber, known as EPDM, Neoprene or Nitrile.

The invention is applicable to various types of installations which are often very complex and where there are strict safety requirements. The installations can be fixed, mobile, land-based or offshore. Relevant installations are in a wind turbine, in a power plant, on a production plant for hydrocarbons or on a vessel. The invention does not limit the choice of material, but the filling element is advantageously made of a material that meets the safety requirements where the filling element is to be used.

The filler element may have a circular cross-section. A circular cross-section has the advantage that it provides a uniform radial force direction perpendicular to the center axis. The invention places no limitations on the shape of the cross-section, but the filling element should have a cross-section which provides a multi-directional elastic deformation and force.

The bracket can be polygonal.

The filling element can be used regardless of the chamber's cross-section, provided that a cavity is formed in the chamber's cross-section. A U-shaped clamp can, for example, enclose the wire 180 degrees and create two cavities against the substrate, where a filling element can be arranged. The filling element can be made in different dimensions so that it can be used in cavities of different sizes and shapes.

In a second aspect, the invention relates more specifically to a method for securing one or more wires in a clip, where the method comprises the steps:

- providing a clamp according to claim 1;

- arranging at least one wire in the clamp;

- arranging at least one filling element in at least one cavity in the clip; and

- arranging the clip in an effective position so that the clip thereby applies an elastic deformation to the filling element.

Execution examples

In the following, examples of preferred embodiments are described which are illustrated in the accompanying drawings, where:

Fig.1 shows in perspective a first embodiment of the invention, comprising a clamp in an inactive position, one wire and filling elements;

Fig.2 shows the clamp in figure 1 in an active position; and where the filling elements are subjected to an elastic deformation.

Fig.3 shows on a larger scale a section of figure 1;

Fig.4 shows a section of figure 2;

Fig.5 shows an end view of figure 3,

Fig.6 shows an end view of figure 4;

Fig.7 shows on a smaller scale and in perspective a compilation of a second, a third, a fourth and a fifth embodiment of the invention;

Fig.8 shows on a larger scale an end view of figure 7;

Fig.9 shows on a larger scale an end view of the second embodiment, comprising a square clamp, four wires with a large diameter and one filler element;

Fig.10 an end view of the third embodiment, comprising a square clip, four wires with a small diameter and one filler element;

Fig.11 an end view of the fourth embodiment, comprising a triangular clamp, three wires and one filling element; and

Fig.12 an end view of the fifth embodiment, comprising a rectangular clamp, six wires and two filling elements.

Figures 1 and 2 show a perspective view of a first embodiment of the invention, comprising a divisible clamp 10 with an upper half 101 and a lower half 102, one wire 5 and four filler elements 1. The filler elements 1 are arranged in the cavities formed by the wire 5 and the clamp's 10 upper and lower half 101, 102.

Figure 1 shows the clamp 10 in an inactive position. The four filling elements 1 are unloaded and retain their original shape. Through this, the filling elements 1 help to keep the upper part 101 and the lower part 102 separate.

Figure 2 shows the clamp 10 in an active position. The upper and lower halves 101, 102 are held together by means of screws (not shown) or in another manner known per se. The four filling elements 1 are pressed together and subjected to an elastic deformation. The deformation means that the filler elements 1 exert a radial force F (see figure 6) against the wire 5 and the clamp 10. If the cross-section of the wire 5 is increased as a result of heat generation, the filler elements 1 will be further pressed together. If the cross-section of the wire 5 is reduced as a result of cooling, the elastic deformation of the filling elements 1 will be reduced. The material properties of the filling element 1 essentially provide a constant force F against the surroundings when the filling element 1 is elastically deformed.

Figure 3 shows a section of Figure 1 on a larger scale.

Figure 4 shows a section of Figure 2.

Figure 5 shows an end view of Figure 3.

Figure 6 shows an end view of Figure 4. When the filling element 1 is subjected to an elastic deformation, a force component F is formed in the filling element 1 which acts against the wire 5 and the adjacent clamp half 102.

Figure 7 shows on a smaller scale and in perspective a compilation of a second, a third, a fourth and a fifth embodiment of the invention.

The second design example comprises a square clamp 40A, four wires 5 and one filling element 1.

The third embodiment comprises a square clamp 40B, four wires 5 and one filling element 1.

The fourth embodiment comprises a triangular clamp 30, three wires 5 and one filling element 1.

The fifth embodiment comprises a rectangular clamp 60, six wires 5 and two filling elements 1.

The four clamps, 40A, 40B, 30, 60 are arranged side by side and screwed to a rail 70. Clamps 40A and 40B are identical, but the wires 5 arranged in clamps 40B have a smaller diameter than the wires 5 arranged in clamps 40A.

The filling element 1 is shown with different diameters and comprises a part 1A and a part 1B. Part 1A is outside the clamps 40A, 40B, 30, 60 and thereby retains its original shape. The part 1B is enclosed by the clamps 40A, 40B, 30, 60 and thereby subjected to an elastic deformation which gives the filling element 1 an outwardly directed force component perpendicular to the central axis of the filling element 1 and essentially radially on adjacent wires 5.

Figure 8 shows an end view of Figure 7 on a larger scale.

Figure 9 shows on a larger scale an end view of the second design example, comprising a square clamp 40A, four wires 5 which are squarely arranged and one filling element 1 arranged in the cavity between the four wires 5.

Figure 10 shows an end view of the third design example, comprising a square clamp 40B, four wires 5 and one filling element 1. Figure 10 shows in principle the same as Figure 9, with the difference that the diameter of the wires 5 is smaller and the diameter of the filling element 1 is bigger.

Figure 11 shows an end view of the fourth embodiment, comprising a triangular clamp 30, three wires 5 and one filler element 1 arranged between the three wires 5.

Figure 12 shows an end view of the fifth embodiment example, comprising a rectangular clamp 60, six wires 5 arranged in pairs at three heights and two filler elements 2 arranged between the wires 5. Figure 12 shows how the invention enables a more compact and space-saving installation of a plurality of wires 5 , in that the wires 5 can be arranged in pairs in height.

It should be noted that all of the above embodiments illustrate the invention, but do not limit it, and those skilled in the art will be able to devise many alternative embodiments without departing from the scope of the appended claims. In the requirements, reference numbers in parentheses should not be seen as limiting.

The use of the verb "to comprise" and its various forms does not exclude the presence of elements or steps not mentioned in the claims. The indefinite articles "an", "ei" or "et" before an element do not exclude the presence of several such elements.

The fact that certain features are listed in different mutually dependent claims does not indicate that a combination of these features cannot be advantageously used.

Claims (4)

Patent claims 1. System for fixing one or more wires (5), where the system comprises a clamp (10, 40A, 40B, 30, 60) adapted to be fixed to a substrate (70), and one or more flexible filling elements (1) , c a r a c t e r i s e r t w e d that - the flexible filling element (1) is arranged to fill a part of a cavity formed between a wire (5) and the clamp (10, 40A, 40B, 30, 60), between several wires (5) and/or between one or more wire and the substrate (70); - the flexible filling element (1) is arranged to apply a force component (F) to the wire (5) in the radial direction of the wire (5) when the flexible filling element (1) is subjected to an elastic deformation when the clamp (10, 40A, 40B, 30, 60) is in an active position. 2. Device according to any one of the preceding claims, where the flexible filling element (1) is made of an elastic material which maintains its elasticity at varying temperatures. 3. Device according to any one of the preceding claims, wherein the cable clip (10, 40A, 40B, 30, 60) is polygonal. 4. Method for fixing one or more wires (5) in a clamp (10, 40A, 40B, 30, 60), characterized in that the method includes the steps: - providing a clamp (10, 40A, 40B, 30, 60) according to claim 1; - arranging at least one wire (5) in the clip (10, 40A, 40B, 30, 60); - arranging the flexible filling element (1) in a part of a cavity formed between a wire (5) and the clamp (10, 40A, 40B, 30, 60), between several wires (5) and/or between one or more wires and the substrate (70); - placing the clamp (10, 40A, 40B, 30, 60) in an active position to thereby apply to the flexible filling element (1) an elastic deformation adapted to exert a force component (F) in the radial direction of the wire (5)