A lightning arrester based on Parylene coating and coating processing method

Abstract

The present invention discloses a Parylene-coated lightning arrester and a coating processing method. The Parylene-coated lightning arrester comprises a lightning arrester and a Parylene coating, wherein the Parylene coating is coated on a valve core column and a composite outer jacket of the lightning arrester. The Parylene coating has advantages such as waterproofness and corrosion resistance as well as good electrical properties, thereby improving the electric field distribution of the lightning arrester during operation and enhancing the insulation performance of the lightning arrester.

Description

Technical Field

[0001] The present invention relates to the technical field of lightning arresters, and in particular to a lightning arrester based on a Parylene coating and a coating processing method. Background Art

[0002] Lightning arresters, sometimes called surge protectors, are used to protect various electrical equipment in power systems from overvoltage damage. Typically connected between a conductor and the ground wire, a lightning arrester diverts high transient overvoltages from the circuit to the ground, preventing damage to electrical equipment caused by the surge.

[0003] Lightning arresters work outdoors for a long time. Although they are protected by synthetic jackets, synthetic jackets are easily affected by the environment, including high temperature, rain, snow or saline-alkali coverage. When the surface of the arrester jacket is seriously polluted, the voltage distribution will be very uneven, which may burn out the parallel resistor and cause a fault, seriously affecting the insulation performance of the arrester.

[0004] During the arrester potting process, the gap between the valve stem and the composite jacket is sealed with low-molecular-weight silicone rubber. The purpose of using silicone rubber potting is to better secure the valve stem and increase insulation resistance. Although silicone rubber offers excellent water resistance and sealing properties, it lacks sufficient insulation against low-molecular-weight vapors and oils. Furthermore, silicone rubber does not adhere well to other materials. Summary of the Invention

[0005] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a lightning arrester based on Parylene coating and a coating processing method, which can improve the insulation performance of the lightning arrester and extend the service life of the lightning arrester.

[0006] In order to solve the above problems, the present invention adopts the following technical solutions:

[0007] A lightning arrester based on a Parylene coating comprises a lightning arrester and a Parylene coating; the lightning arrester is a composite-jacketed metal oxide lightning arrester, and the Parylene coating is an HT-type Parylene coating; the Parylene coating is applied to the surface of the composite jacket and the surface of the valve core column of the lightning arrester; the Parylene coating applied to the surface of the valve core column fills the gaps in the resistor stack and enables better adhesion between the silicone rubber and the valve core column; the Parylene coating isolates the valve core column from water molecules or stain molecules present in the lightning arrester; and the Parylene coating applied to the surface of the composite jacket of the lightning arrester improves the electrical performance of the lightning arrester.

[0008] The raw material for preparing the HT type Parylene coating is 1,1,2,2,9,9,10,10-octafluoro-p-xylene ring dimer.

[0009] The thickness of the HT type Parylene coating is 10-50 μm.

[0010] The coating processing method of the arrester based on Parylene coating comprises the following steps:

[0011] The first step is the surface pretreatment of the arrester parts: first, the surface of the arrester parts is pretreated by sandblasting, and the surface is pre-polished and deburred;

[0012] The second step is ultrasonic cleaning: soak the pre-treated arrester parts and perform ultrasonic cleaning, then rinse with clean water, dehydrate, and then dry; then activate the surface of the dried arrester parts with a coupling agent;

[0013] The third step is to coat the valve core column with a Parylene film by using a vapor deposition method. The Parylene raw material is heated in a sublimation furnace until it sublimates. The sublimated gas enters a cracking furnace and is cracked into monomers. The generated monomers are then sent to a vacuum deposition chamber below 0°C for polymerization and deposition on the valve core column. The remaining gas is recovered through a cold trap.

[0014] The fourth step is potting after assembly: assemble the parts of the arrester, fix the resistor on the valve core column of the arrester with epoxy resin, put the low molecular weight silicone rubber into a vacuum tank and evacuate it. After the bubbles in the rubber liquid have completely escaped, promptly pour the rubber liquid into the cavity between the valve core column and the composite jacket of the arrester to shape the rubber;

[0015] The fifth step is coating the composite jacket of the lightning arrester: the vapor deposition method is used to coat the composite jacket of the lightning arrester with Parylene film. The specific method is as follows: the Parylene raw material is heated to sublime in the evaporation chamber of the sublimation furnace, and the sublimated gas enters the cracking chamber of the cracking furnace to be cracked into monomers, and then the generated monomers are sent to the vacuum deposition chamber at room temperature to be polymerized and deposited on the composite jacket of the lightning arrester, and the remaining gas is recovered through a cold trap.

[0016] The third and fifth steps are to be carried out in a dedicated deposition device, which includes a sublimation furnace, a cracking furnace, a deposition chamber, a cold trap and a vacuum pump arranged in sequence.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects:

[0018] After the arrester composite jacket is coated with Parylene, the arrester improves its electrical performance, such as reducing the dielectric constant and dielectric loss factor. The thermal stability and weather resistance are significantly improved. The composite jacket has low gas permeability, low moisture absorption and stable chemical properties.

[0019] The Parylene coating on the valve stem, which is made up of stacked resistors, fills the gaps between the resistors and improves adhesion between the silicone rubber and the valve stem. The coating isolates the valve stem from water molecules and other contaminants inside the arrester, preventing the resistors from burning out due to water ingress or contamination that could affect voltage distribution.

[0020] Insulated composite-jacketed metal oxide arresters operate outdoors for extended periods and are significantly affected by the environment. While arresters are regularly inspected and their composite jackets cleaned, applying a coating can help maintain better performance during these inspections and cleanings, potentially extending the inspection and cleaning cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic structural diagram of the Parylene coating-based arrester provided by the present invention.

[0022] Figure 2 The figure is a flow chart of the coating processing method of the arrester based on Parylene coating.

[0023] Figure 3 Schematic diagram of coating processing equipment. DETAILED DESCRIPTION

[0024] In order to more clearly understand the technical solution provided by the present invention, it is further explained below with reference to the accompanying drawings and specific implementation cases.

[0025] A lightning arrester based on a Parylene coating comprises a lightning arrester and a Parylene coating.

[0026] The arrester is a composite jacket metal oxide arrester, and the Parylene coating is applied on the surface of the composite jacket and the surface of the valve core column of the arrester to improve the insulation performance of the arrester and increase the service life of the arrester.

[0027] The Parylene coating is HT type Parylene.

[0028] The raw material for preparing the HT type Parylene is 1,1,2,2,9,9,10,10-octafluoro-p-xylene ring dimer (AF4).

[0029] The thickness of the HT type Parylene coating is 10-50 μm.

[0030] like Figure 1As shown, the lightning arrester coated with Parylene coating in this embodiment includes a valve core column 1 formed by stacking resistor sheets, a Parylene coating 2 on the valve core column, a lightning arrester composite jacket 3 covering the valve core column 1, and a Parylene coating 4 on the lightning arrester composite jacket.

[0031] Example:

[0032] like Figure 2 As shown, the above-mentioned Parylene-coated arrester and coating processing method are as follows, including the following steps:

[0033] The first step is the surface pretreatment of the arrester parts: first, the surface of the arrester parts is sandblasted and polished to remove burrs and other pre-operations. After acceptance, the next step is carried out;

[0034] The second step is ultrasonic cleaning: hot-dip clean the parts after the previous step's pretreatment to soften, separate, and dissolve the contaminants on the parts. Place the parts in an ultrasonic cleaner and clean them for 3-5 minutes. Rinse with running water and dehydrate them. Then, dry them with hot air or steam. Activate the surface of the dried arrester parts with a silane coupling agent. After acceptance, proceed to the next step.

[0035] The third step involves coating the valve stem using a vapor deposition method to coat the valve stem with a Parylene film. The method involves vaporizing the 1,1,2,2,9,9,10,10-octafluoro-p-xylene dimer in a sublimation furnace at a temperature of 130-170°C and a pressure of 100-133 Pa. The vaporized material then enters a pyrolysis furnace at a temperature of 630-670°C and a pressure of 50-67 Pa, where it is pyrolyzed at high temperatures to produce a gaseous reactive intermediate. This gaseous reactive intermediate then enters a deposition chamber containing the valve stem, maintained at a temperature below 0°C and a pressure of 10-13.3 Pa, where it undergoes a polymerization reaction, forming a Parylene film on the surface of the valve stem. The deposition rate is 0.1-5 μm / h. A cold trap is used to collect unreacted gases and protect the vacuum pump.

[0036] The fourth step is potting after assembly: Assemble the parts of the lightning arrester, fix the valve core column of the lightning arrester with epoxy resin, put the low molecular weight silicone rubber into a vacuum tank and evacuate it. After the bubbles in the rubber liquid have completely escaped, immediately perform potting to form it.

[0037] Step 5: Coating the arrester composite jacket: Parylene is deposited on the arrester composite jacket using vapor deposition. 1,1,2,2,9,9,10,10-octafluoro-p-xylene dimer is vaporized in a sublimation furnace at a temperature of 130-170°C and a pressure of 100-133 Pa. The vaporized material then enters a cracking furnace at a temperature of 630-670°C and a pressure of 50-67 Pa, where it undergoes high-temperature cracking to produce reactive intermediates. The gaseous reactive intermediates then enter a deposition chamber containing the arrester composite jacket, maintained at a temperature below 0°C and a pressure of 10-13.3 Pa, where they undergo polymerization, forming a Parylene film on the composite jacket surface. The deposition rate is 0.1-5 μm / h. Finally, a cold trap is used to collect unreacted gases and protect the vacuum pump.

[0038] The third and fifth steps are to be carried out in a dedicated deposition device, the schematic diagram of which is shown in the figure below. Figure 3 As shown, the process includes a sublimation furnace, a cracking furnace, a deposition chamber, a cold trap, and a vacuum pump. This process needs to be carried out under vacuum conditions, so a vacuum pump is required to evacuate the equipment.

Claims

1. A coating processing method for a Parylene-coated lightning arrester, the Parylene-coated lightning arrester comprising a lightning arrester and a Parylene coating; the lightning arrester is a composite-jacketed metal oxide lightning arrester, and the Parylene coating is an HT-type Parylene coating; the Parylene coating is applied to the surface of the composite jacket and the valve core of the lightning arrester; the Parylene coating applied to the valve core fills gaps in the resistor stack and improves adhesion between the silicone rubber and the valve core; the Parylene coating isolates the valve core from water molecules or contaminants present within the lightning arrester; and the Parylene coating applied to the composite jacket of the lightning arrester improves the electrical performance of the lightning arrester. Its characteristics are: The coating processing method comprises the following steps: The first step is the surface pretreatment of the arrester parts: first, the surface of the arrester parts is pretreated by sandblasting, and the surface is pre-polished and deburred; The second step is ultrasonic cleaning: soak the pre-treated arrester parts and perform ultrasonic cleaning, then rinse with clean water, dehydrate, and then dry; then activate the surface of the dried arrester parts with a coupling agent; The third step is to coat the valve core column with a Parylene film by using a vapor deposition method. The Parylene raw material is heated in a sublimation furnace until it sublimates. The sublimated gas enters a cracking furnace and is cracked into monomers. The generated monomers are then sent to a vacuum deposition chamber below 0°C for polymerization and deposition on the valve core column. The remaining gas is recovered through a cold trap. The fourth step is potting after assembly: assemble the parts of the arrester, fix the resistor on the valve core column of the arrester with epoxy resin, put the low molecular weight silicone rubber into a vacuum tank and evacuate it. After the bubbles in the rubber liquid have completely escaped, promptly pour the rubber liquid into the cavity between the valve core column and the composite jacket of the arrester to shape the rubber; The fifth step is coating the composite jacket of the lightning arrester: the vapor deposition method is used to coat the composite jacket of the lightning arrester with Parylene film. The specific method is as follows: the Parylene raw material is heated to sublime in the evaporation chamber of the sublimation furnace, and the sublimated gas enters the cracking chamber of the cracking furnace to be cracked into monomers, and then the generated monomers are sent to the vacuum deposition chamber at room temperature to be polymerized and deposited on the composite jacket of the lightning arrester, and the remaining gas is recovered through a cold trap.

2. The coating processing method of a Parylene-coated arrester according to claim 1, characterized in that: The third and fifth steps are to be carried out in a dedicated deposition device, which includes a sublimation furnace, a cracking furnace, a deposition chamber, a cold trap and a vacuum pump arranged in sequence.

3. The coating processing method of a Parylene-coated arrester according to claim 1, characterized in that: The raw material for preparing the HT type Parylene coating is 1,1,2,2,9,9,10,10-octafluoro-p-xylene ring dimer.

4. The coating processing method of a Parylene-coated arrester according to claim 1, characterized in that: The thickness of the HT type Parylene coating is 10-50 μm.

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