Application of a glaze for super-high voltage porcelain insulators in glazing sand

Abstract

The application relates to the technical field of electric porcelain insulators, and particularly discloses application of a glaze for superhigh-voltage porcelain insulators in glazing sand, which comprises the following raw materials in parts by mass: microinclined feldspar 10-20 parts, soda feldspar 10-20 parts, high-plasticity clay 5-15 parts, kaolin 7-12 parts, calcined talc 10-14 parts, wollastonite 4-10 parts, quartz powder 15-25 parts, zirconium silicate 6-10 parts and aluminum oxide 2-6 parts. A preparation method comprises the following steps: S1, weighing the raw materials according to the glaze for superhigh-voltage porcelain insulators; S2, mixing and grinding all the raw materials, sieving after grinding, obtaining glaze slurry after sieving, and drying the glaze slurry to obtain the glaze. The scheme is used to solve the problem of reduced bending strength of the porcelain insulator after sanding on the end part in the prior art, and the problem of complex process and high cost caused by separately glazing the head part and the umbrella part to improve the bending strength and cooperate with sanding.

Description

Technical Field

[0001] This invention relates to the field of electrical porcelain insulator technology, specifically to the application of a glaze material for ultra-high voltage porcelain insulators in glazing sand. Background Technology

[0002] With the development of the national economy and the improvement of electrification levels, electricity has become increasingly prominent in the energy sector, and ensuring electricity security has gradually become one of the core elements of the new energy security strategy. Due to the surge in electricity consumption, the proportion of electricity on the consumer side will gradually increase. Faced with ever-growing electricity demand, the task of ensuring a stable supply of electricity to the industry remains arduous.

[0003] To meet the needs of high-voltage power transmission projects, porcelain insulators are also divided into high-voltage insulators and ultra-high-voltage insulators according to their application scope. Currently, the highest-grade ultra-high-voltage insulator is the high-strength aluminum porcelain insulator. Due to the wide range of ultra-high voltage applications, the bending strength requirement for high-strength aluminum porcelain insulators before glazing is no less than 140MPa, and after glazing, the bending strength requirement is no less than 160MPa. However, with the development of the electrical age, the porcelain industry is also constantly developing. For high-voltage power transmission projects with even higher pressures, such as 500 kV to 1000 kV, the bending strength requirements for insulators are even higher.

[0004] Currently, there is increasing research on insulators in the industry, and our company has also conducted in-depth research on porcelain insulators. For glazed materials, we can achieve a bending strength of over 200MPa after glazing. However, because porcelain insulators need to be fixedly installed, they must be used in conjunction with metal parts. For example, suspension porcelain insulators need to be used with iron caps and steel feet. To improve the bonding strength between the iron caps, steel feet and porcelain insulators, sand is often applied to the surface of the insulator where the iron caps and steel feet are installed to increase the friction coefficient of the porcelain insulators, thereby improving the connection strength between the iron caps, steel feet and porcelain insulators. However, because sand has low strength and a large difference in thermal expansion coefficient compared to porcelain insulators, the overall bending strength of porcelain insulators that originally achieved a bending strength of over 200MPa after glazing actually decreases under thermal stress, resulting in a decline in the electromechanical performance of porcelain insulators.

[0005] To address the aforementioned issues, existing technologies involve separately glazing porcelain insulators. One type of glaze is applied to the end that connects to metal components (such as iron caps or steel feet), while a different glaze is applied to the umbrella section of the porcelain insulator. For example, suspension porcelain insulators have a head glaze and an umbrella glaze. By changing the glaze material of the head glaze to better match the sand on the head, it is possible to ensure that the bending strength of the porcelain insulator can still exceed 200 MPa after glazing and sanding. However, this method requires glazing the head and umbrella sections separately, and both the head and umbrella sections involve glazing the inner and outer surfaces, making it very costly to achieve porcelain insulators with high bending strength. Summary of the Invention

[0006] The present invention aims to provide a glaze for ultra-high voltage porcelain insulators and its preparation method, so as to solve the problem of reduced bending strength of porcelain insulators after sanding at the ends in the prior art, while the method of applying head glaze and umbrella glaze separately to cooperate with sanding to improve bending strength is complicated and costly.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A glaze for ultra-high voltage porcelain insulators comprises the following raw materials in parts by weight: 10-20 parts microcline, 10-20 parts albite, 5-15 parts high-plasticity clay, 7-12 parts kaolin, 10-14 parts calcined talc, 4-10 parts wollastonite, 15-25 parts quartz powder, 6-10 parts zirconium silicate, and 2-6 parts alumina.

[0008] Preferably, as an improvement, the glaze obtained after all raw materials are prepared contains the following chemical composition: 60-72% SiO2, 14-17% Al2O3, less than 0.7% Fe2O3, 3-4% CaO, 3-5% MgO, 2-3.5% K2O, 1.5-3% Na2O, and 4-7% ZrO2.

[0009] Preferably, as an improvement, the plagioclase is 10-18 parts and the albite is 12-20 parts.

[0010] Preferably, as an improvement, the calcined talc is 10-12 parts.

[0011] Preferably, as an improvement, the quartz powder is 17-22 parts.

[0012] This invention also provides a method for preparing glaze for ultra-high voltage porcelain insulators, comprising the following steps: S1. Weigh the raw materials according to the glaze material for ultra-high voltage porcelain insulators; S2. Mix all raw materials and grind them. After grinding, sieve the mixture to obtain a glaze slurry. Dry the glaze slurry to obtain the glaze material.

[0013] Preferably, as an improvement, iron removal treatment is required in step S2 by sieving.

[0014] The principle and advantages of this scheme are as follows: The formula of this invention, through controlling the amounts of microcline, albite, Ordos clay, kaolin, calcined talc, wollastonite, quartz powder, zirconium silicate, and alumina, ensures that the content of alumina, calcium oxide, magnesium oxide, sodium oxide, and zirconium oxide in the resulting glaze is controlled within a very suitable range. Furthermore, the excellent effects of each raw material are maximized through synergistic action (combining viscosity, high-temperature fluidity, suspension, gloss, and strength of the glaze), resulting in the most ideal overall effect. This formula also ensures that the glaze produced under this formula... The glaze, when applied to the blank, can achieve a bending strength far exceeding that of existing technologies (enabling high-strength aluminum porcelain insulators to reach 220MPa, or even 233.7MPa, after glazing and sanding, based on the bending strength of the blank of 170MPa), greatly improving the bending strength of the suspended porcelain after sanding. It also allows for one-time glazing of the head umbrella during the first glazing of the blank, greatly simplifying the glazing process and reducing the production cost for enterprises. In addition, the resulting suspended porcelain can also ensure smoothness, flatness, no color difference, and good wear resistance and corrosion resistance.

[0015] This invention also provides a method for using a glaze for ultra-high voltage porcelain insulators, comprising the following steps: Step 1: One-time glazing of the porcelain insulator head and umbrella: Grind the glaze material into a glaze slurry, and then put the head and umbrella part of the blank into the glaze slurry. The glazing method is used to achieve the overall glazing of the porcelain insulator inside and out, and obtain the glazed blank. Step 2: Apply glaze sand to the glazed blank: Apply glaze adhesive to the head of the glazed blank, and then apply glaze sand to the glaze adhesive surface of the glazed blank to obtain a glazed and sanded blank. Step 3: Place the glazed and sand-coated blanks in a kiln for firing to obtain ultra-high voltage porcelain insulators.

[0016] Furthermore, as an improvement, the glaze-coating sand in step two is prepared using the following steps: I. Prepare the glaze into glaze powder, and mix the glaze powder with porcelain sand evenly; II. While the porcelain sand and glaze powder are being stirred evenly, CMC glue is added continuously. This allows the glue to coat the glaze powder onto the porcelain sand, forming a glaze-coated sand with an inner layer of porcelain sand, a middle layer of glaze powder, and an outer layer of glue.

[0017] Furthermore, as an improvement, step two also includes the following sub-steps: III. Apply glaze-containing adhesive to the head of the glazed blank. The glaze-containing adhesive is made by mixing and stirring the glaze and adhesive. After applying the glaze-containing adhesive, apply glaze-coating sand to the surface of the glaze-containing adhesive to obtain a glazed and sanded blank.

[0018] This invention produces glazed sand using glaze, porcelain sand, and adhesive. The glaze powder is first mixed with the porcelain sand, coating the inner layer of the porcelain sand with a layer of glaze powder. Then, with the addition of adhesive, the glaze powder is further encapsulated. Any glaze powder that did not adhere during the mixing process is also incorporated into the adhesive, forming a glazed adhesive layer. This increases the glaze content on the porcelain sand (creating a structure where the core is porcelain sand, the middle layer is primarily glaze, and the outer layer is glazed adhesive). This improves the strength of the glaze coating on the porcelain sand during subsequent firing and allows for a gradual transition in the coefficient of thermal expansion of the porcelain insulator surface, contributing to increased bending strength.

[0019] Furthermore, in this invention, the glaze is mixed with adhesive to form a glaze-containing adhesive. This glaze-containing adhesive is used for coating before sanding, allowing the glaze in the adhesive to approach the glaze layer of the blank due to the absorbency of the blank. The glaze-coating sand adheres to the glaze-containing adhesive layer by filling, extrusion, or sandblasting. Under extrusion or spraying pressure, the glaze-coating sand is embedded into the glaze-containing adhesive layer, and may even come into contact with the glaze on the blank. Thus, before firing, the glaze is distributed in the inner, middle, and outer layers of the porcelain insulator, preventing glaze discontinuity. During sintering, the glaze, glaze and sand, and glaze and blank are linked together through physical and chemical reactions, erosion / diffusion / reaction, forming a whole. This ensures that there are no problems such as sand loss, sand deficiency, or sand separation during sintering, greatly improving the bending strength of the porcelain insulator after sanding. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating a method for preparing glaze for ultra-high voltage porcelain insulators according to an embodiment of the present invention.

[0021] Figure 2 This is a cross-sectional view of the glazed sand made with glaze in this invention. Detailed Implementation

[0022] The following detailed description illustrates the specific implementation method: The reference numerals in the accompanying drawings of the instruction manual include: porcelain sand 1, glaze powder 2, and glue 3.

[0023] A glaze for ultra-high voltage porcelain insulators comprises the following raw materials in parts by weight: 10-20 parts microcline, 10-20 parts albite, 5-15 parts high-plasticity clay, 7-12 parts kaolin, 10-14 parts calcined talc, 4-10 parts wollastonite, 15-25 parts quartz powder, 6-10 parts zirconium silicate, and 2-6 parts alumina.

[0024] Combination Figure 1 A method for preparing a glaze for ultra-high voltage porcelain insulators includes the following preparation steps: S1. Weigh the raw materials, including 10-20 parts of microcline, 10-20 parts of albite, 5-15 parts of high plasticity clay (Ordos clay is used for high plasticity clay), 7-12 parts of kaolin, 10-14 parts of calcined talc, 4-10 parts of wollastonite, 15-25 parts of quartz powder, 6-10 parts of zirconium silicate, and 2-6 parts of alumina.

[0025] S2. After mixing all the raw materials, wet ball milling is used. After ball milling, the mixture is sieved to remove iron. After sieving, a glaze slurry is obtained. The glaze slurry is dried to obtain the glaze material.

[0026] The chemical composition of the glaze obtained by the above method is shown in the table below:

[0027] The above-mentioned glaze can be used to glaze the surface of porcelain insulators. This embodiment takes the glazing of suspension porcelain insulators as an example, and the glazing process of porcelain insulators using the above-mentioned glaze includes the following steps: Step 1: First-time glazing of the porcelain insulator umbrella: Grind the glaze material into a glaze slurry, ensuring the slurry can pass through a 360-mesh sieve. The residual weight after sieving should be 0.05%-0.18%, and the specific gravity of the glaze slurry should be 1.45-1.55 g / cm³. 3 Then, the head and umbrella-shaped parts of the unglazed blank are completely immersed in the glaze slurry. The glaze is applied to the inside and outside of the ceramic insulator by immersion glazing to obtain a glazed blank. In this step, because the sintered blank has a very high water absorption, the glaze adheres to the surface of the blank under the action of water absorption after the blank is immersed in the glaze slurry. The glaze immersion requirements are: the glaze thickness is controlled at 0.25-0.60 mm and the immersion time is 5-7 seconds.

[0028] Step Two: Applying Glazed Sand to the Glazed Blank: Apply glaze-laden adhesive to the head of the glazed blank, then apply porcelain sand containing glaze powder onto the glazed blank coated with glaze-laden adhesive, resulting in a glazed and sanded blank. The specific steps of this step are as follows: I. Preparation of glaze powder and uniform mixing of glaze powder and porcelain sand: The glaze of the present invention is ground into powder to obtain dry glaze powder with a fineness of less than 80 micrometers. Then, porcelain sand is taken. The porcelain sand is C130 porcelain with a particle size of 0.8 to 1.5 mm. The porcelain sand and glaze powder are stirred evenly. Some glaze powder will adhere to the surface of the porcelain sand. In this embodiment, the mass ratio of porcelain sand to glaze powder is controlled at 1:(0.6 to 0.9).

[0029] II. While the porcelain sand and glaze powder are thoroughly mixed, continue stirring and gradually add glue. This allows the glue to coat the glaze powder onto the porcelain sand, forming an inner layer of porcelain sand, a middle layer primarily composed of glaze powder, and an outer layer mainly composed of glue—a glaze-coated sand layer (e.g.,...). Figure 2 As shown in the figure, this step yields glazed sand with distinct, sticky particles and an outer glaze particle size of 1.4 to 1.8 mm. The mass of the glue used in the preparation of the glazed sand is 1 / 4 to 1 / 3 of the mass of the glaze powder.

[0030] During the preparation and preparation of the glazed sand, the glazed sand is tightly covered with a container to prevent it from drying out and to ensure that the surface of the glazed sand is sticky when used.

[0031] III. Apply glaze-containing adhesive to the inside and outside of the head of the glazed blank. The glaze-containing adhesive is an adhesive mixed with glaze slurry (glaze slurry after iron removal during glaze production). The mass ratio of glaze slurry to adhesive in the glaze-containing adhesive is controlled at 1:(0.8~1.1). The glaze slurry used is the same as that used for the first glazing of the head umbrella. The adhesive used in the adhesive and the adhesive used in the glaze coating sand are both commonly used sanding adhesives in the industry, such as CMC adhesive. Then, apply the glaze coating sand to the outer and inner surfaces of the head of the glazed blank by filling or sandblasting. In this step, the outermost layer of the glaze coating sand is an adhesive layer, which is sticky. The glaze-containing adhesive also has high viscosity, which allows the glaze coating sand to adhere evenly to the surface of the head of the glazed blank (without sand falling off, piling up, or lacking sand, and with good uniformity), resulting in a glazed and sanded blank.

[0032] Step 3: Place the glazed and sand-coated blanks in a drawer kiln for glazing and firing, and then cool to room temperature to obtain high-grade suspended porcelain. This high-grade suspended porcelain can be used in ultra-high voltage and even extra-high voltage power transmission projects.

[0033] The glaze prepared using the above formula can be used for a single glazing of the umbrella head, eliminating the need for separate glazing of the head and umbrella parts. It can also be used as an outer coating of the porcelain sand during sanding and as a material used in conjunction with adhesive. This allows the blank to form an inner glaze layer, a middle glaze-adhesive layer, and an outer glaze-coated sand layer after a single glazing of the head. Because the glaze-coated sand embeds itself into the middle and inner layers under mutual pressure or the force of sandblasting, the glazes in each layer erode, diffuse, and react with each other after sintering, thus bonding together to form a whole. The inner, middle, and outer layers can be well bonded together, and the outer layer... The porcelain sand is coated with glaze, ensuring a smooth and flat exposed glaze surface for the porcelain insulator, while also stabilizing the sand and maintaining a high roughness at the sand-coated area. Furthermore, the application of glaze in the inner, middle, and outer layers allows for a gradual transition between the glaze and sand on the surface of the insulator head, thus minimizing differences in expansion coefficients and significantly reducing thermal stress. The coordinated proportions of the raw materials in the glaze enable the resulting insulator to achieve a bending strength of 220-233.7 MPa, far exceeding existing technologies. The resulting insulator also boasts a smooth, flat umbrella-shaped surface, free of pinholes and color variations, and exhibits excellent wear and corrosion resistance. This not only avoids the problem of decreased bending strength after sand coating in existing technologies but also represents a breakthrough in bending strength. Moreover, the resulting glaze can be used for a single glazing of the insulator head, greatly simplifying the manufacturing process for insulators meeting ultra-high pressure requirements and reducing manufacturing costs.

[0034] In this embodiment, multiple experimental and control groups were tested to obtain the glaze formula for the suspended porcelain with the aforementioned flexural strength. The specific composition of each raw material is as follows: Microcline was selected from Shaanxi Province, and its main chemical analysis parameters are as follows:

[0035] The sodium feldspar used is from Linxiang, and its main chemical analysis indicators are as follows:

[0036] Ordos clay is a type of clay with a high hydration rate, averaging 95%. It is also a highly plastic clay with an average binding strength of around 5.0 MPa. Its main chemical control indicators are as follows:

[0037] The kaolin used is from Xianyang, which is a medium-to-low plastic clay with an average binding strength of about 0.5 MPa. Its main chemical control indicators are as follows:

[0038] Calcined talc from Zichuan was used, and its main chemical analysis parameters are as follows:

[0039] The wollastonite used is from Luzhou, and its main chemical analysis parameters are as follows:

[0040] The quartz powder used is from Jiangxi Province, and its main chemical analysis control indicators are as follows:

[0041] Zirconium silicate using Huaan Zirconium silicate has the following key chemical control indicators:

[0042] The alumina used is Kaiyuan alumina, and its main chemical analysis control indicators are as follows:

[0043] The specific test data is as follows: Table 1 - Comparative experimental data before and after changes in microcline dosage

[0044] Table 2 - Comparative experimental results before and after changes in microcline dosage

[0045] As can be seen from Tables 1 and 2, changing the amount of microcline and albite will not only reduce the overall bending strength of the suspended porcelain, but also cause problems such as poor smoothness and pinholes.

[0046] Table 3 - Comparative experimental data before and after changes in calcined talc dosage

[0047] Table 4 - Comparative experimental results before and after changes in calcined talc dosage

[0048] As can be seen from Tables 3 and 4, both excessive and insufficient calcined talc content will result in insufficient high-temperature fluidity. Consequently, after glazing and sanding, the suspended porcelain will not only have a strength below 200 MPa and poor smoothness, but also, due to excessive calcined talc content, more and overlapping crystals will occur, resulting in a dull glaze and color difference.

[0049] Table 5 - Comparative experimental data before and after changes in wollastonite dosage

[0050] Table 6 - Comparative experimental results before and after changes in wollastonite dosage

[0051] As shown in Tables 5 and 6, when the wollastonite content is too low and the clay content is too high, the relative viscosity of the glaze is too high, while the high-temperature fluidity is too low, resulting in the suspended porcelain after firing being both rough and having pinholes. When the wollastonite content is too high, the relative viscosity is greatly reduced and the high-temperature fluidity is greatly increased, solving the problems of roughness and pinholes. However, glaze bubbles are easily generated, which leads to a significant decrease in wear resistance and corrosion resistance. Moreover, the flexural strength of the suspended porcelain after firing can only reach a maximum of about 194 MPa, which does not break through the existing flexural strength of suspended porcelain.

[0052] Table 7 - Comparative experimental data before and after changes in quartz powder dosage

[0053] Table 8 - Comparative experimental results before and after changes in quartz powder dosage

[0054] As shown in Tables 7 and 8, when the quartz powder content is too low, the relative viscosity of the glaze increases, and the high-temperature fluidity at the lower firing position deteriorates, resulting in poor smoothness and flatness of the fired porcelain and the presence of pinholes. At the same time, the flexural strength cannot be improved. When the quartz powder content is too high and the clay content is too low, although the glaze surface of the umbrella part is smooth and flat, without pinholes, and has good wear and corrosion resistance, its flexural strength has just exceeded 200 MPa, and the flexural strength has not been significantly improved. In addition, due to the insufficient clay content, the glaze slurry suspension performance is poor, which affects the uniformity of the glaze in the glaze body and leads to color difference problems.

[0055] Table 9 - Comparative experimental data before and after changes in zirconium silicate dosage

[0056] Table 10 - Comparative experimental results before and after changes in zirconium silicate dosage

[0057] As shown in Tables 9 and 10, when the zirconium silicate content is too low, the relative viscosity of the glaze is too high and the high-temperature fluidity at the lower firing position is too low, resulting in suspended porcelain after firing, with problems such as strength of less than 200 MPa, pinholes, color difference, and poor wear resistance and corrosion resistance. When the zirconium silicate content is too high, although there is no color difference on the surface and the wear resistance and corrosion resistance are quite good, problems such as roughness, pinholes, and even glaze shrinkage occur, and the bending strength is also less than 210 MPa, making it impossible to achieve a breakthrough in bending strength.

[0058] It should be noted that due to the large amount of experimental data, not all results are presented. Through comparative research, it was found that controlling the alumina content between 2 and 6 parts per liter ensures minimal impact on the overall effect while keeping other components constant, guaranteeing the quality of the glaze and ensuring flexural strength. However, excessively low alumina content will reduce the glaze's effectiveness. of Hardness, but excessive use will reduce the high-temperature fluidity of the glaze. thereby This reduces the quality of the glaze.

[0059] Based on the experimental data above, it can be seen that the formula of this invention, through the control of the amounts of microcline, albite, Ordos clay, kaolin, calcined talc, wollastonite, quartz powder, zirconium silicate, and alumina, enables the glaze prepared under this formula to achieve a bending strength far exceeding that of existing technologies when applied to the blank. This allows the high-strength aluminum porcelain insulator to reach 220 MPa, or even 233.7 MPa, on top of the blank's bending strength of 170 MPa, after glazing and sanding, greatly improving the bending strength of the suspended porcelain after sanding. Furthermore, it allows for one-time glazing of the head umbrella during the first glazing of the blank, greatly simplifying the glazing process and reducing production costs for enterprises. In addition, the resulting suspended porcelain can also guarantee a smooth and flat surface, no color difference, and good wear resistance and corrosion resistance.

[0060] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. The application of a glaze material for ultra-high voltage porcelain insulators in glazing sand, characterized in that: The glaze is composed of the following raw materials in parts by weight: 10-18 parts microcline, 12-20 parts albite, 5-15 parts high plasticity clay, 7-12 parts kaolin, 10-14 parts calcined talc, 4-10 parts wollastonite, 15-25 parts quartz powder, 6-10 parts zirconium silicate, and 2-6 parts alumina. The glaze obtained after mixing all the raw materials has the following chemical composition: SiO2 60-72%, Al2O3 14-17%, Fe2O3 less than 0.7%, CaO 3-4%, MgO 3-5%, K2O 2-3.5%, Na2O 1.5-3%, ZrO2 4-7%, and IL 3.5-7.0%. The total chemical composition of the glaze is 100%. It also includes the following steps: I. Prepare the glaze into glaze powder, and mix the glaze powder with porcelain sand evenly; II. While the porcelain sand and glaze powder are being stirred evenly, CMC glue is added continuously. This allows the glue to coat the glaze powder onto the porcelain sand, forming an inner layer of porcelain sand, a middle layer of glaze powder, and an outer layer of glaze-coated sand with glaze glue.

2. The application of the glaze material for ultra-high voltage porcelain insulators according to claim 1 in glaze-coating sand, characterized in that, The calcined talc is 10-12 parts.

3. The application of the glaze material for ultra-high voltage porcelain insulators according to claim 1 in glaze-coating sand, characterized in that, The amount of quartz powder is 17-22 parts.

4. The application of the glaze material for ultra-high voltage porcelain insulators according to any one of claims 1-3 in glazing sand, characterized in that, The preparation method of glaze for ultra-high voltage porcelain insulators includes the following steps: S1. Weigh the raw materials according to the glaze; S2. Mix all raw materials and grind them. After grinding, sieve the mixture to obtain a glaze slurry. Dry the glaze slurry to obtain the glaze material.

5. The application of the glaze material for ultra-high voltage porcelain insulators according to claim 4 in glazing sand, characterized in that: In step S2, iron removal is performed by sieving.

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