A process of forming a seal for a cable gland

Abstract

A process of forming a seal for a cable gland 1,2 comprising the steps of: determining the size of seal 20 required and selecting a mould (figure 5a,100), (figure 6, 199); pouring a setting material i

Description

Field of the Invention The present invention relates to the process of forming a seal for a cable gland, in particular but not exclusively for outdoor use. Background In many societies there is an increasing danger of inclement weather. For electrical installations or junction boxes that are exposed to the weather, this can be an issue, as can ingress of small animals or insects. Prior Art CN 217 821 014 (CHEN) discloses a glue-filled and sealed outdoor optical fibre protection box for optical cables, comprising a box body and an optical cable connector installed in the box body, characterized in that the box body includes an upper box body and a lower box body that are fastened to each other and the upper box body is provided with a material injection port and a vent hole, and the optical cable connector is installed in a cavity formed by fastening the upper box body and the lower box body, and the potting glue is injected from a material injection port In the cavity to fill the gap in the cavity. CN 215 071 594 (XIAO) discloses an insulation waterproof box satisfying a small-wire-diameter wire as branch connection, and relates to the technical field of wire and cable protection, the insulation waterproof box comprises a cavity used for placing a main cable and a small branch wire connecting wire clamp, and the cavity is filled with silicone grease or epoxy resin to realize sealing of the whole cavity so as to achieve a waterproof purpose of a cable connection part; the two ends of the cavity are provided with pipe openings used for a cable to penetrate through and the top end of a cover is provided with a glue pouring port. US 2012 0 025 471 (ANDRICK et al) discloses a self adjusting gasket to retard leakage at a joint between an associated first pipe and an associated second pipe comprising: a wedge shaped body made of a generally compressible, leak proof material having a profile that includes: a tapered front portion, a planar rear portion, a first contact surface, an inclined second contact surface, including a first fin having a trailing edge oriented generally normal to the first contact surface and a second fin spaced from the first fin, a generally continuous annular cavity located in the wedge shaped body wherein the cavity is not symmetrically shaped, and a fluid disposed in the cavity. Summary of the Invention According to a first aspect of the present invention there is provided a process of forming a seal for a cable gland comprising the steps of: determining the size of seal required; selecting a mould to reflect the size of the seal required; pouring a setting material into the selected mould; waiting for the fluid to cure into a resiliently deformable material; removing the seal from the mould; and inserting the seal to the cable gland. Preferably the mould is a tray with a plurality of moulds therein to which setting material is poured. Each mould has a cable bore to define an opening in the seal through which the cable passes. The plurality of moulds in one tray may be of the same size and a user may select the tray with the size of mould required. Advantageously a user can form multiple seals at the same time using one tray. Alternatively one tray may have of a plurality of different size moulds so that a user can select the desired mould size or sizes required on the tray to form the seal or seals required. According to a second aspect of the present invention there is provided a process of forming a seal for a cable gland having the steps of: arranging a displaceable mould at a sealing region of the cable gland; pouring a setting material into the mould arranged at the sealing region of the cable gland; waiting for the fluid to cure into a resiliently deformable material; removing the mould to leave the seal in the sealing region. Preferably the displaceable mould may comprise a funnel shape with a cable bore to guide setting material to the seal region of the cable gland so that setting material is poured and directed to the sealing region of the cable gland whilst allowing for passage of the cable through the opening in the seal created by cable bore. Once the setting material has been cured the mould can be removed, leaving the seal in situ. Ideally the displaceable mould is sized to fit the dimensions of the cable gland (stuffing gland) with which the seal created from the mould will be used. In this way when the nut is tightened the seal is compressed and fills the region where the nut engages thereby covering all gaps. According to a third aspect of the invention there is provided a process of forming a seal in a cable gland so that the cable gland acts as the mould, the cable gland has at least two chambers, each chamber is sealed by a breakable layer; the process having the steps of: arranging a cable in the cable gland; activating a mixing mechanism that breaks the breakable layers to allow mixing of contents of the at least two chambers to form a seal of cured resiliently deformable material within the cable gland. In this way a seal for a cable gland can be made at the site of fitting, to the desired size requirements, from a material that provides an effective reliable seal. Advantageously the system avoids the requirement for an installer to carry multiple seals of different sizes as the seals can be made on site. The process also ensures that the seals are made when required and thus avoids the risk of using a cable gland with old seals that may have degraded and be less reliable. Advantageously the seal, and / or a cable gland incorporating the seal ensures that sealing around the cable received to the cable gland achieves the purpose of preventing moisture and dust particles from entering an electrical connector or junction box. The seal that is formed is typically toroidal for use with a bipartite cable gland. The seal is arranged to be fitted between two parts of the gland such that the seal engages with parts of the cable gland when the seal is compressed by movement of the nut of the cable gland so that the seal expands radially under pressure to seal against a cable passing through the channel of the cable gland. In a preferred embodiment the setting material is a two part solution that is mixed to form a solution that will cure into a resiliently deformable material. Preferably the two part solution is a silicone gel. A preferred example of the setting material is Wiska (RTM) MP-Gel. In some embodiments the cured material has a Shore hardness of below 30A. In preferred embodiments the moulds may have cable bores of 9mm, 17mm or 36mm which correspond to commonly required openings through the seals. In addition to formation of a seal arranged in the cable gland a setting material may also be applied at the cable gland closure such that closure generally forces the setting material around a junction to be sealed. With reference to the third aspect of the invention the cable gland has at least two chambers, and adjacent chambers are separated by a breakable layer. The breakable layer is preferably a foil layer. A mixing mechanism causes one or more of the breakable layers to break and enable mixing of the contents of the chambers. Preferably a first chamber is filled with a first part of a two part solution and the second chamber is filled with a second part of the two part solution. In this way when the two parts mix, the solution solidifies to form the watertight seal. In a preferred embodiment the mixing mechanism includes a threaded cap that is turned to move along a threaded collar of the cable gland to force at least one of the breakable layers to break. For example the threaded cap may engage with the breakable layer to cause breakage. Preferably the modified cable gland has an annular safety cuff to prevent erroneous activation of the mixing mechanism. Therefore the cuff must be removed before movement of the threaded cap is enabled. The application refers to a cable gland for receiving a cable but it is appreciated that the cable gland may also receive a pipe. A preferred embodiment of the invention will now be described by way of example only and with reference to the Figures in which: Brief Description of Figures Figure 1 shows an isometric view of a first embodiment of a cable gland device according to the present invention; Figure 2 shows a reverse isometric view of the embodiment of the device shown in Figure 1; Figure 3 shows an exploded isometric view of the embodiment of the device shown in Figure 1; Figure 4 shows a reverse exploded isometric view of the embodiment of the device shown in Figure 1; Figures 5 show isometric views of a first embodiment of a mould for a sealing device according to the present invention; Figure 6 shows an isometric view of a second embodiment of a mould for a sealing device according to the present invention; Figure 7 shows a reverse isometric view of the embodiment of the mould for the device shown in Figure 6; Figure 8 shows an isometric view of a second embodiment of the device according to the present invention; Figure 9 shows a reverse isometric view of the embodiment of the device shown in Figure 8; Figure 10 shows an exploded isometric view of the embodiment of the device shown in Figure 8; Figure 11 shows a reverse exploded isometric view of the embodiment of the device shown in Figure 8; and Figure 12 shows a sectional view of the embodiment of the device shown in Figure 8. Detailed Description of Figures The Figures show cable glands 1,2, 299, seals 20 and moulds 100, 199 used to form the seals 20. With reference to the embodiment shown in Figure 1 there is shown a toroidal seal 20 arranged in a bipartite cable gland with an adjustable nuts 1 received to a body 2 with a collar 12. The seal 20 is toroidal with flat upper and lower faces that engage with the cable gland to form a watertight seal. As the parts of the cable gland are screwed together (the nut 1 is adjusted on the collar 12), the seal expands radially under pressure to seal against a cable (not shown) passing through the bore A of the cable gland. In particular reference to the embodiment of the cable gland shown in Figure 1, this cable gland comprises a seal 20 according to the fist aspect of the present invention, whereby the seal is fully formed and emplaced in the cable gland in use. The cable gland may otherwise be envisaged to comprise a standard cable gland as is known in the art, being formed in brass, aluminium, steel, or plastics for example, and having a male body 2 with a threaded collar 12, and female threaded nut 1. The collar 12 comprises endmost teeth 11, that receive and the seal 20 and further compress against the seal 20 as the nut 1 is wound onto the collar 12. The cable or pipe passes through this bore A in use, whereby tightening of the nut 1, 2 on the collar will tighten the resilient teeth 11 also towards the bore and thereby the cable passing therethrough. In this way the cable gland is secured onto the cable at a first end, with it envisaged that the second end may be secured onto a junction box or the like, having a threaded collar. In the pictured embodiment the first end is provided with the seal 20, which has two opposing flat faces 21, 22, with the upper face 21 arranged towards the nut 1 and the lower face 22 towards the collar 12. The upper face 21 is narrower in diameter, and an open bore 23 passes through orthogonally between the faces 21, 22. The seal 20 is emplaced within the teeth 11 and inside the nut 1. The cable is passed through the opening of the nut and the collar, and the nut 1 is screwed onto the collar 12, such that the nut depresses the seal 20 and expands it radially towards and against the cable (not shown) in the bore A, thereby preventing passage of moisture, and limiting rust and damage within the junction box. The seal 20 may either be formed in the cable gland using a displaceable mould 100 shown in Figures 5A, 5B, or in a mould tray 199 as shown in Figures 6 and 7. It is appreciated that each mould can be produced in any colour, with colours signifying what size gland the seal formed will work with. It may be envisaged that the mould may be provided in a range of sizes so the correct diameter is provided with all standard glands. In use a user mixes the setting material and pours it into a displaceable mould 100, or a mould tray 199. With reference to Figure 5 there is an example if a displaceable mould 100. The displaceable mould 100 has a funnel shaped bowl 40 and funnel delivery tube 41. Setting material (gel) is poured through the delivery tube 41 to file the funnel shaped bowl 40. A cable bore 43 creates an opening in the seal 20 for the cable to pass. The cable (not shown) is inserted through the aperture made in the seal 20 that is formed by the cable bore 43 of the displaceable mould 100. Once the setting material poured into the displaceable mould 100 has cured the mould is removed and can be reused over multiple installations. The displaceable mould 100 is shaped and dimensioned to ensure setting material is guided to the sealing region of the cable gland and does not enter other areas such as into a junction box. With particular reference to the embodiment of the mould 199 shown in Figure 6 the embodiment comprises a substantially flat rear panel 52, and six upstanding mould sections 5. The mould sections 5 are provided in two sets of different size dimensions and may be formed in rigid plastic or metal or alloy, or silicone or rubber, for example so as to aid in expelling the seals 20 from the moulds. The moulds comprise a circular open topped wall 50, and a central bore pillar 51. Figures 8 to 12 show an example of a modified cable gland 299 with a standard cable gland 81 with a foil cover 13 and a foil seal 31 which when the seal 31 separating to two chambers 10, 30 is broken allows two parts of a two part setting material to mix and solidify to form the resiliently deformable seal. In the pictured embodiment the modified cable gland 299 comprises an upper chamber 10 and a lower chamber 30 separated by foil seal 31 which prevents passage through the bore until the seal 31 between the two chambers is broken. The upper chamber 10 has a circular foil cover 13 arranged over its outer surface, namely the outer perimeter of the nut bore. The foil cover 13 acts to prevent liquid coming out from the cable gland 299. Preferably the foil cover 13 has a hole (not shown) to accept the cable but that prevents mixing of the two part setting material until the cable is in place and the foil seal 31 is broken. A central foil seal 31 is located between the upper chamber 10 and the lower chamber 30, internally within the bore proximate the threaded collar 12 that connects with the junction box (not shown) in use. The embodiment 299 comprises a plastic cover 3 over the threaded collar 12 end, which internally includes a female screw thread, running on the collar of the gland. An annular safety cuff 32 is arranged on part of the body 2 of the cable gland 81 that prevents thread movement of the cap along this collar 12 at rest, as shown in the Figures. However upon breaking / removal of this annular safety cuff 32 the cover 3 may be screwed up so that it moves along the collar 12 and, thereby, breaks the 5 intermediate seal 31, allowing the material in chambers 10 and 30 to mix to form the cured seal (not shown in Figures 8 to 12). The invention has been described by way of examples only and it will be appreciated that variation may be made to the above-mentioned embodiments without departing 10 from the scope of protection as defined by the claims.

Claims

1. A process of forming a seal for a cable gland comprising the steps of: determining the size of seal required; selecting a mould to reflect the size of the seal required; pouring a setting material into the mould; waiting for the fluid to cure into a resiliently deformable material; removing the seal from the mould; and inserting the seal to the cable gland.

2. A process of forming a seal in a cable gland having the steps of arranging a displaceable mould at a sealing region of the cable gland; pouring a setting material into the mould arranged at the sealing region of the cable gland; waiting for the fluid to cure into a resiliently deformable material; removing the mould to leave the seal in the sealing region.

3. A process of forming a seal in a cable gland with at least two chambers separated by at least one breakable layer having the steps of: arranging a cable in the cable gland; activating a mixing mechanism that breaks the breakable layers to allow mixing of contents of the chambers to form a seal of cured resiliently deformable material.

4. A process of forming a seal for a cable gland according to claim 1, claim 2 or claim 3 wherein the setting material is a two part solution that is mixed to form a solution that will cure into a resiliently deformable material.

5. A process of forming a seal for a cable gland according to claim 4 wherein the two part solution is a silicone gel.

6. A process of forming a seal for a cable gland according to claim wherein the setting material is Wiska (RTM) MP-Gel.

7. A process of forming a seal for a cable gland according to any preceding claim wherein the setting material cures into a resiliently deformable material that has a Shore hardness of below 30 on the A scale.

8. A process of forming a seal for a cable gland according to claim 1 including a tray with a plurality of moulds.

9. A process of forming a seal for a cable gland according to claim 8 wherein the tray has moulds of two or more different sizes.

10. A process of forming a seal for a cable gland according to claim 2 wherein the mould is funnel shaped with a cable bore to guide setting material to the seal region of the cable gland so that setting material is poured and directed to the sealing region of the cable gland whilst allowing for passage of the cable through the cable bore.

11. A mould for use in the process of forming a seal according to any preceding claim with a cable bore of 9mm.

12. A mould for use in the process of forming a seal according to any of claims 1 to 10 with a cable bore of bore of 17mm.

13. A mould for use in the process of forming a seal according to any of claims 1 to 10 with a cable bore of bore of 36mm.

14. A cable gland according to claim 3 having two chambers separated by at least one breakable layer and a mixing mechanism; wherein a first chamber is filled with a first part of a two part solution and the second chamber is filled with a second part of the two part solution.

15. A cable gland according to claim 14 wherein the mixing mechanism includes a threaded cap that is turned to move along a threaded collar of the cable gland to force at least one breakable layer to break and thereby permit mixing of the contents of the chambers.

16. A cable gland according to claim 15 with an annual safety cuff to prevent erroneous activation of the mixing mechanism.

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