Method for packaging glass or ceramic electrical insulators with a polysiloxane coating

Abstract

The present application relates to a method for packing electrical insulators (4) for high or extra-high voltage, such as insulators for power lines made of insulating material selected from glass or ceramic, and in particular to packing electrical insulators having a protective hydrophobic coating of elastomeric polysiloxane on their surface, under vacuum or inert gas.

Description

TECHNICAL FIELD

[0001] The field of the present application relates to the packaging of high or extra high voltage electrical insulators, such as electrical line insulators made of insulating material selected from glass or ceramic, and in particular electrical insulators coated on their surface with a protective hydrophobic silicone rubber. BACKGROUND

[0002] It is known that electrical insulators are packaged in wooden boxes, either individually or in the form of strings of electrical insulators, for transport and / or storage. However, during the handling of the boxes, the friction and / or impact between the insulators and the wood of the box can cause damage to the silicone coating.

[0003] The use, packaging and transport of pre-coated ceramic insulators are described in the article "Pre-coated ceramic insulators for transmission line applications" by E.A. Cherney et al., IEEE Transactions on Dielectrics and Electrical Insulation, Vol. 20, pp. 237-244, February 2013.

[0004] A shock-absorbing packaging obtained by heat-sealing shock-absorbing sheets and a thermoplastic resin film and its use are described in patent document EP1323642A1.

[0005] Patent document EP3299304B1 describes a suction device for placing a vacuum insulation panel under vacuum or for producing a vacuum bag.

[0006] In order to protect the electrical insulators from friction and / or impact in the wooden box, foam fillers are placed in the box to isolate the electrical insulators from the wood of the box.

[0007] However, the wooden box containing the electrical insulators and equipped with the foam filler can be stored for long periods at the construction site before the installation of the insulators. Since the construction site can be located in an area affected by severe external conditions, such as heavy rain, floods or contact with standing water, moisture can be absorbed by the foam filler. When the filler is wet, its humidity comes into contact with the electrical insulators for long periods, which can cause the silicone coating to flake off, making the electrical insulators damaged before installation. The silicone coating can also be damaged when the electrical insulators are in direct contact with standing water for long periods.

[0008] Therefore, manufacturers are seeking a packaging method for electrical insulators that overcomes these drawbacks. SUMMARY

[0009] The object of the present application is to provide a method for packaging glass or ceramic electrical insulators having a silicone coating that better protects the electrical insulators from friction and / or impact during the handling of the box containing the electrical insulators; at the same time, it limits the humidity of the environment and the formation of water vapor that can come into contact with the electrical insulators during storage.

[0010] To this end, the subject of the present application is a method for packaging glass or ceramic electrical insulators coated with a polysiloxane coating, comprising the following steps:

[0011] - placing the electrical insulators or the string of electrical insulators from the open portion of the bag into the water- and air-tight sealed bag, said open portion of the bag being defined by two edges, said two sealing edges being sealed to each other to form a sealing band and to sealably close the bag;

[0012] - superimposing said two edges to form the sealing band and placing the sealing band between the two sealing bars of the sealer;

[0013] - placing the first end of the suction nozzle between the two edges of the bag to be sealed;

[0014] - closing the sealing bars so that the first end of the suction nozzle remains between the two edges to be sealed and clamps the sealing strip;

[0015] - connecting the second end of the suction nozzle to the vacuum source until a suitable vacuum degree is reached;

[0016] - when the suitable vacuum degree is reached, removing the suction nozzle remaining between the two edges of the bag and sealing by fusion of the sealing strip.

[0017] The method of the present application can have the following specific features:

[0018] - the first end of the suction nozzle can be flat;

[0019] - the multilayer material of the bag can be polyethylene terephthalate (PET) / aluminum / oriented polyamide (OPA) / polyethylene (PE);

[0020] - the multilayer material of the bag is recyclable or biodegradable;

[0021] - inert gas is introduced into the vacuum bag before sealing by fusion of the sealing strip.

[0022] Advantageously, the vacuum packaging of the insulators or the string of insulators in a water- and air-tight bag allows storing in all types of storage areas and enables maintaining the seal before use, thus protecting it from the surrounding humidity, thus guaranteeing a good integrity of the polysiloxane coating of the electrical insulators.

[0023] This packaging method is even more advantageous, the bag forming the primary packaging being resistant to mechanical handling and transport, it also protects the electrical insulators from impacts and / or abrasions with other materials forming the secondary packaging, such as wooden crates.

[0024] The flat shape of the first end of the suction nozzle improves its performance in holding the bag between the two edges to be sealed; it also improves the sealing of the sealing strip during the process of extracting air from the bag, because the sealing bar of the sealing machine usually has PTFE or rubber strips, which are more suitable for the flat nozzle port.

[0025] In some embodiments, an inert gas may preferably be introduced into a vacuum-sealed bag to improve the storage conditions of electrical insulators with a polysiloxane coating. Attached Figure Description

[0026] A better understanding of the invention and its other advantages can be achieved by reading the following description and accompanying drawings, wherein:

[0027] Figure 1 The diagram illustrates an electrical insulation string used in power transmission lines.

[0028] Figure 2 The illustration schematically shows a string of electrical insulators consisting of multiple electrical insulators to be packaged in this application;

[0029] Figure 3 Different packaging steps of the method of this application are shown;

[0030] Figure 4 A sealing machine for packaging one or more electrical insulators in a sealed bag is shown schematically.

[0031] Figure 5A and Figure 5B The illustration schematically shows strings of electrical insulators packaged in bags to be sealed under vacuum or inert gas conditions. Figure 5A This is a front view. Figure 5B This is a cross-sectional view. Detailed Implementation

[0032] The packaging method described in this application is applicable to parts made of insulating materials, such as glass or ceramics, and is particularly suitable for electrically insulating electrical components, such as high-voltage and ultra-high-voltage electrical insulators.

[0033] Figure 1 An example is given of an insulator string 1 consisting of electrical insulators 4 suspended on a cable tower 3 for a high-voltage or ultra-high-voltage transmission line 2. Figure 2 It shows Figure 1 In an insulator string 1, there are multiple consecutive electrical insulators 4, for example, an electrical insulator 4 with a tempered glass skirt, whose outer surface 4' is coated with a polysiloxane protective layer. When stored for a long time, the polysiloxane coating on the skirt tends to be damaged due to prolonged and periodic contact with moisture, and the polysiloxane coating may detach from the skirt.

[0034] The packaging method in this application is... Figure 3The electrical insulators 4 are shown in a block diagram. One or more electrical insulators 4, made of glass or ceramic and coated with a coating of polysiloxane, are packaged in a bag 5 under vacuum or inert gas, as shown in Figure 5A and 5B The bag 5 is watertight and airtight, and has mechanical strength, so as to protect the electrical insulators 4 from impacts and / or abrasions with other materials during handling and / or transport of the electrical insulators 4. The bag 5 is also weldable, so that it can be sealed.

[0035] The bag 5 can be made of any waterproof, air-permeable and mechanically strong material, preferably a multilayer material of polyethylene terephthalate (PET) / aluminum / oriented polyamide (OPA) / polyethylene (PE), which has shown satisfactory results in protecting the polysiloxane coating of the electrical insulators 4 in humid storage areas. Bags 5 made of recyclable or biodegradable multilayer materials with waterproof and airtight properties can be preferably used.

[0036] The packaging method according to the present application can be applied not only to the electrical insulators 4 but also to a string 1 of electrical insulators 4, which can be of a length generally comprised between 1 and 1.5 meters, or can be longer.

[0037] In the present application, the method comprises a first step 101 in which the electrical insulators 4 (or a string 1 of electrical insulators) are introduced into the bag 5 from the open portion (not shown) of the bag 5, which is defined by two edges 6 and 6' which can be sealed to each other to form a sealing band 7 which, once sealed, hermetically closes the bag 5.

[0038] When the electrical insulators 4 are introduced into the bag 5, a second step 102 comprises superimposing the two edges 6 and 6' of the open portion of the bag 5 to form a sealing band 7 which protrudes from the bag 5, so as to be placed Figure 4 between the two sealing bars 8 of the sealer 9.

[0039] Before sealing the bag 5, it is necessary to evacuate the air from the bag 5 using an air suction nozzle 10 connected to a vacuum source 11, for example a vacuum pump. To this end, in a step 103, a first end of the air suction nozzle 10 is placed between the two edges 6 and 6' of the bag 5 to be sealed, and a second end of the air suction nozzle 10 is connected to the vacuum source 11.

[0040] Then, in a step 104, the two sealing bars 8 are brought into contact with each other, clamping the first end of the air suction nozzle 10 between the two edges 6 and 6' by applying pressure on the sealing band 7, clamping the two edges 6 and 6'.

[0041] Therefore, the bag 5 is clamped under pressure, and in a step 105 the vacuum source 11 is activated until a suitable and controllable degree of vacuum is reached.

[0042] When the desired appropriate vacuum level is reached, the suction nozzle 10 is withdrawn from the sealing bar 7 to remove the suction nozzle 10 in step 106, and the sealing bar 7 is sealed by fusion before the vacuum-sealed bag 5 is released by opening the sealing bar 8, as shown in Figure 5A and 5B .

[0043] In one embodiment, at least the first end of the suction nozzle 10 is flat, which makes it easier to connect to the flexible seal provided on each sealing bar 8, thus enabling a better seal when extracting air from the bag 5.

[0044] In another embodiment, when the appropriate vacuum level is reached, an inert gas can be introduced into the vacuum bag 5 by known means, for example, through the sealing bar 7 parallel to the suction nozzle 10 before sealing by fusion of the sealing bar 7.

[0045] The present application is not limited to the above-described embodiments and can be modified without departing from the scope of the present application.

Claims

1. A method for packaging line electrical insulators (4) for high or extra-high voltage power lines, suspended on cable towers, of glass or ceramic with a coating of polysiloxane, characterised in that comprising the steps of: placing a line insulator (4) or a string (1) of line insulators (4) into a bag (5) to be sealed through an open portion of the bag (5), said bag (5) being made of a multilayer material impermeable to water and air and comprising an aluminum layer, said open portion of the bag (5) being defined by two edges (6, 6') which are sealed to each other to form a sealing band (7) to sealably close the bag (5); overlapping the two edges (6, 6') to form the sealing band (7) and placing the sealing band (7) between two sealing bars (8) of a sealing machine (9); placing a first end of a suction nozzle (10) between the two edges (6, 6') of the bag (5) to be sealed; closing the sealing bars (8) to hold the first end of the suction nozzle (10) between the two edges (6, 6') to be sealed and to clamp the sealing band (7); connecting a second end of the suction nozzle (10) to a vacuum source (11) until a predetermined vacuum degree is reached; when the predetermined vacuum degree is reached, removing the first end of the suction nozzle (10) held between the two edges (6, 6') of the bag (5) and sealing by fusion of the sealing band (7).

2. The method of claim 1, wherein: The first end of the suction nozzle (10) is flat.

3. The method according to claim 1 or 2, characterized in that: The multilayer material of the bag (5) is made of the following layers: polyethylene terephthalate (PET) / aluminum / oriented polyamide (OPA) / polyethylene (PE).

4. The method of claim 1 or 2, wherein: The multilayer material of the bag (5) is recyclable or biodegradable.

5. The method of claim 1 or 2, wherein: Before sealing the sealing band (7), inert gas is introduced into the vacuum bag (5).

6. The method of claim 3, wherein: Before sealing the sealing band (7), inert gas is introduced into the vacuum bag (5).

7. The method of claim 4, wherein: Before sealing the sealing band (7), inert gas is introduced into the vacuum bag (5). Before sealing the sealing band (7), inert gas is introduced into the vacuum bag (5).

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