Cable joint

Abstract

This utility model pertains to electrical engineering, specifically to devices for connecting and protecting electrical cables. Specifically, the utility model pertains to cable joint designs employing cold-shrink technology to ensure cable entry sealing. The technical result consists in reducing the risk of loss of the cable joint housing seal. For this purpose, an annular protrusion with a rear surface perpendicular to the cable joint housing's cable entry is provided on the joint housing. A cold-shrink tube is installed on the entry, overlapping the protrusion. The cavity, formed by the rear surface of the protrusion, the inner surface of the tube, and the outer surface of the housing, is filled with a sealing compound. 2 c.p. fils, 1 fig.

Description

[0001] Field of technology of the utility model

[0002] This utility model pertains to electrical engineering, specifically to devices for connecting and protecting electrical cables. Specifically, the utility model relates to cable joint designs using cold-shrink technology to ensure cable entry sealing. The utility model can be used in various industries, including transportation, energy, telecommunications, construction, and utilities, for installing cable lines operating in difficult operating conditions, including underground or outdoor installations.

[0003] Prior art of the utility model

[0004] Various cable joint designs are available for sealing cable connections, including cast-in joints and joints using heat-shrink or cold-shrink components. The latter have become widespread due to their ease and speed of installation, which requires no heat or open flame.

[0005] The technical solution known from the document [RU 193849 U1, publication date 11 / 19 / 2019] was chosen as a prototype. The cable joint disclosed in the document contains a housing having a cable entry with slots at the ends in the form of petals, wherein the cable entry has an outer annular protrusion, and a cold-shrinkable tube is installed on the cable entry.

[0006] A disadvantage of the prototype is the high risk of loss of the cable joint housing's seal during long-term operation. This disadvantage is due to the prototype's design relying solely on the radial compression force generated by the shrinkable cold-shrink tubing. The annular projection in the prototype serves only a narrow mechanical purpose—preventing the stretched tubing from slipping off the housing during storage and installation—but it does not contribute to the formation of an additional sealing barrier. Consequently, during operation, under the influence of cyclic temperature deformations and external vibration loads, the materials of the housing and tubing, which have different coefficients of thermal expansion, experience mutual micro-shifts. This leads to a localized weakening of the clamping force between the tubing and the housing, leading to the formation of gaps and capillary channels at their junction.Penetration of moisture through these channels into the coupling causes corrosion of the connections, a drop in insulation resistance and, ultimately, can lead to electrical breakdown and complete failure of the cable line.

[0007] Thus, the technical problem that the utility model is aimed at solving is the need to eliminate the existing shortcomings of the prototype.

[0008] Disclosure of the essence of the utility model

[0009] The technical result that the utility model is aimed at achieving is to reduce the risk of loss of tightness of the cable joint housing.

[0010] The essence of the utility model is as follows.

[0011] The cable joint comprises a housing with a cable entry with cold-shrink tubing installed thereon. The cable entry has an annular projection on the outside for securing the cold-shrink tubing, which is installed overlapping said projection. The projection has a sliding (lead-in) surface and a rear surface located perpendicular to the axis of the housing. Unlike the prototype, the cavity formed by the rear surface of the projection, the inner surface of the tube, and the outer surface of the housing is filled with a sealant.

[0012] The cable joint housing with cable entry provides mechanical protection of the cable connection from external influences and initial positioning of the components. To further reduce the risk of loss of sealing, the cable joint housing may have a hole for filling its interior with electrical insulating compound. Two-component polyurethane or epoxy resins can be used as electrical insulating compounds.

[0013] The cable gland is fitted with a cold-shrink tube, which creates the primary seal by radially compressing the cable surface and the gland. To further reduce the risk of loss of sealing, the cable gland can be designed as a petal-shaped collet formed by triangular cutouts.

[0014] The cable gland is equipped with an external annular protrusion. This protrusion has a profile that includes a sliding (entry) and stop surface. The sliding (entry) surface, designed, for example, as a cone or rounded (chamfered), facilitates the shrinking of the cold-shrink tubing, ensuring its smooth passage over the protrusion without damage. The stop surface, located perpendicular to the housing axis, prevents axial displacement or slippage of the tubing from the cable gland under operating loads. Cold-shrink tubing was chosen due to its advantages over heat-shrinkable alternatives, as shrinking does not require the use of heating equipment or an open flame. This eliminates the risk of thermal deformation of the housing or damage to the tubing itself during installation.

[0015] The closed annular cavity formed by the thrust perpendicular surface of the protrusion and the inner surface of the shrunk tube is filled with a sealing compound, creating an additional sealing contour. During the tube shrinkage process, radial pressure is exerted on this compound, ensuring that all irregularities and potential capillary channels at the junction of the housing and tube are filled, while maintaining a low sealing compound consumption. Various viscous or elastic materials can be used as sealing compounds, such as non-hardening polymer mastics based on butyl rubber, silicone compounds, or other compounds with high adhesion to the housing and tube materials.

[0016] The utility model is characterized by a previously unknown set of essential features, distinguished by the fact that the cavity formed by the rear surface of the protrusion, the inner surface of the tube, and the outer surface of the housing is filled with a sealing compound. Filling this cavity with the sealing compound creates increased contact pressure on the sealing compound during the tube shrinkage process. This causes the sealing compound to displace air, distribute evenly over the entire contact surface, and fill micro-irregularities and possible capillary channels at the junction of the tube and housing. This ensures the formation of an additional elastic seal, independent of the elasticity of the tube itself.The use of a sealing compound specifically in the contact zone between the thrust surface of the protrusion and the inner surface of the tube ensures long-term and stable sealing of the most vulnerable section of the cable joint - the transition from the tube to the housing, where the likelihood of gaps forming is greatest due to differences in the properties and geometry of the materials.

[0017] The set of essential features of the utility model ensures reliable mechanical fixation of the cold-shrinkable tube due to the geometry of the annular protrusion with a thrust surface and allows for the creation of an additional sealing circuit by introducing a sealing compound that operates in a closed cavity under the pressure of the shrinkable tube and guarantees sealing in the zone of potential risk of loss of tightness, regardless of the quality and condition of the elastic tube during operation.

[0018] This ensures the achievement of a technical result consisting in reducing the risk of loss of tightness of the cable joint housing.

[0019] The utility model has a set of essential features previously unknown in the prior art, which indicates its compliance with the patentability criterion of “novelty”.

[0020] Implementation of a utility model

[0021] The utility model is explained by the following materials.

[0022] Fig. 1 - cable joint, general view, longitudinal section.

[0023] To illustrate the possibility of implementation and a more complete understanding of the essence of the utility model, a particular case of its implementation is presented below, which can be changed or supplemented in any way, while the present utility model is in no way limited to the presented particular case of its implementation.

[0024] The cable joint comprises a hollow housing 10 made of a dielectric polymer material and provided with an opening for subsequent filling of the internal cavity with an electrical insulating compound. Housing 10 has at least one cable entry 12 designed for inserting a cable into the internal cavity of housing 10 and formed in the form of a petal-shaped collet formed by several longitudinal triangular cutouts.

[0025] On the outside of the cable entry 12, a ring-shaped protrusion is made monolithically with it for fixing the cold-shrinkable tube, including the input surface 14 and the rear surface 16. The sliding (input) surface 14 is made with a slope to facilitate installation, while the rear surface 16 is located perpendicular to the longitudinal axis of the housing 10.

[0026] A cold-shrinkable tube 18 is installed on the cable entry 12 with an overlapping annular protrusion in such a way that it radially compresses the surface of the cable entry 12, the annular protrusion and forms a closed cavity, which is formed by the rear surface 16 of the protrusion and the inner surface of the cold-shrinkable tube 18 adjacent to it. The said cavity is filled with a viscous or elastic sealing composition 20 (for example, a polymer mastic).

[0027] The utility model operates as follows.

[0028] The coupling is supplied assembled, in which the free part of the cold-shrinkable tube 18 is in a stretched state and is held in this state by a removable spiral cord.

[0029] During installation, after connecting the cable cores inside housing 10, the spiral cord is removed. This causes tube 18 to shrink, tightly pressing the outer cable sheath against the surface of cable entry 12. As tube 18 shrinks, the inner surface of tube 18 exerts increasing pressure on sealant 20. Under this pressure, the viscous sealant 20 spreads throughout the cavity, filling all microscopic irregularities and potential capillary channels at the material interface. Simultaneously, the shrunken portion of tube 18 is secured by an annular protrusion, which prevents axial displacement or slippage of tube 18 from cable entry 12 during operation.Moreover, due to the fact that the cavity behind the rear surface 16 is filled with a sealing compound 20, which is under pressure during the shrinkage of the tube 18, a sealing contour is formed, which, in combination with the mechanical fixation of the tube by the protrusion, ensures the tightness of the housing 10. After this, the internal cavity of the housing 10 can be filled with an electrical insulating compound to fix the connection of the wires and create the main volume of electrical insulation and additional sealing of the coupling.

[0030] Thus, the technical result is achieved, which consists in reducing the risk of loss of tightness of the cable joint housing.

Claims

1. A cable joint comprising a housing having a cable entry with a cold-shrinkable tube installed thereon, wherein the cable entry has an annular projection on the outside for securing the cold-shrinkable tube, which is installed with an overlap of said projection, wherein the projection has a sliding surface and a rear surface located perpendicular to the axis of the housing, characterized in that the cavity formed by the rear surface of the projection, the inner surface of the tube and the outer surface of the housing is filled with a sealing compound.

2. The coupling according to item 1, characterized in that the cable entry is made in the form of a petal-shaped collet formed by triangular cutouts.

3. The coupling according to item 1, characterized in that the housing has an opening for filling the internal cavity with electrical insulating compound.

Images