Special head umbrella one-time glaze process for super high pressure hanging porcelain

Abstract

The application relates to the technical field of porcelain insulators, and particularly discloses a one-time glazing process for a head-umbrella of an ultrahigh-voltage suspension porcelain insulator, which comprises the following steps: S1, preparing glaze slurry from glaze, wherein the glaze is prepared from the following raw materials in parts by mass: microclin 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; and S2, placing the head and umbrella of a blank into the glaze slurry to realize one-time glazing of the head and umbrella of the blank by adopting a glazing mode. The glaze slurry for glazing is contained in a glazing tank, the blank is placed vertically during glazing, a glazing device is arranged below the blank, and the glazing device is used for spraying the glaze slurry in the glazing tank to the blank after sucking the glaze slurry. The scheme is used to solve the problems of complex process and high cost in the prior art that the head and umbrella of a porcelain insulator are glazed separately.

Description

Technical Field

[0001] This invention relates to the field of porcelain insulator technology, specifically to a one-time glazing process for a special head umbrella for ultra-high voltage suspension porcelain. 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 could originally reach 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 (hereinafter referred to as suspension porcelain) have a head glaze and an umbrella glaze. By changing the glaze material of the head glaze to achieve a better match with the sand on the head, 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 (to avoid the risk of glaze cracking at the junction of the head and umbrella sections, an appropriate amount of water-retaining agent and plasticizer needs to be added to the head glaze, but this also results in a relatively higher viscosity of the head glaze, making it more prone to "glaze scale" in the pipes supplying the head glaze, which can reduce flow or even cause pipe blockage). 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 one-time glazing process for the head umbrella of ultra-high voltage porcelain insulators, so as to solve the problems of complex process and high cost in the existing technology of glazing the head and umbrella parts separately.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A one-time glazing process for a special high-pressure suspended ceramic umbrella includes the following steps: S1. Prepare the glaze into a glaze slurry, wherein the glaze is made from the following raw materials in parts by weight: 10-20 parts microcline, 10-20 parts sodium feldspar, 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. S2. Place the head and umbrella parts of the blank into the glaze slurry and use the glazing method to glaze the head and umbrella parts of the blank in one go.

[0008] Preferably, as an improvement, the glaze slurry can pass through a sieve with a mesh size of not less than 360 mesh.

[0009] Preferably, as an improvement, the glaze slurry is sieved through a screen, and the residual weight after sieving is 0.05%-0.18% to ensure that the glaze slurry has good suspension properties and ensures the uniformity of the glaze layer after the umbrella is glazed once.

[0010] Preferably, as an improvement, the thickness of the glaze layer after the umbrella is 0.25-0.6 mm after one glazing is completed.

[0011] Preferably, as an improvement, the glaze slurry for glazing is placed in a glazing tank. During glazing, the blank is placed upright, and a glazing spraying device is set below the blank. The glazing spraying device is used to draw the glaze slurry in the glazing tank and spray it onto the inner hole of the blank. This is to avoid the problem of poor glaze slurry flow on the inner surface of the blank, especially at the inner hole of the head, which would affect the glazing quality.

[0012] Preferably, as an improvement, the glazed blank is held at the top of the blank by a suction cup. Since the top of the suspended porcelain is neither the stress surface nor the exposed surface of the porcelain insulator (it will be covered by the steel cap), even if the top of the blank cannot be glazed or is glazed less due to the suction cup, it will not affect the bending strength of the suspended porcelain.

[0013] Preferably, as an improvement, the blank is wrapped in a thin film after the first glazing is completed.

[0014] Preferably, as an improvement, the glazing process maintains the flow of glaze slurry relative to the blank, avoids glaze material sedimentation, and ensures the uniformity of the glaze layer.

[0015] Preferably, as an improvement, the plagioclase is 10-18 parts and the albite is 12-20 parts. This scheme enables the glaze formula to reduce the melting temperature of the glaze, reduce the high-temperature viscosity of the glaze and increase the gloss of the glaze, while also minimizing the impact on the chemical stability of the glaze. It ensures that the expansion coefficient of the glaze can match both the blank and the porcelain sand used for subsequent sanding. This ensures that the bending strength of the umbrella after one glaze dip is significantly improved relative to the blank, and that the bending strength of the blank can still be greatly improved after the glaze is coated with porcelain sand.

[0016] Preferably, as an improvement, the calcined talc is 10-12 parts; by controlling the amount of calcined talc, the calcined talc can improve the mechanical strength and thermal stability of the glaze, and is conducive to combining with other raw materials to control the annual growth of the glaze within a reasonable range, thus ensuring the excellent quality of the glaze surface after the porcelain is fired.

[0017] Preferably, as an improvement, the quartz powder is 17-22 parts. By controlling the quartz powder, the silica content in the glaze glass is increased, which acts as a skeleton and helps to reduce the expansion coefficient of the glaze and improve the wear resistance, hardness, strength, whiteness, transparency and chemical stability of the glaze surface.

[0018] Preferably, as an improvement, the overall chemical composition of the glaze includes: 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.

[0019] The principle and advantages of this solution are as follows: This invention controls the content of alumina, calcium oxide, magnesium oxide, sodium oxide, and zirconium oxide in the glaze formula (amounts of microcline, albite, Ordos clay, kaolin, calcined talc, wollastonite, quartz powder, zirconium silicate, and alumina) within a very suitable range. Furthermore, through the synergistic effect of the raw materials, the excellent effects of each material are maximized (combining viscosity, high-temperature fluidity, suspension properties, gloss, and strength of the glaze), resulting in the most ideal overall effect. The glaze prepared under this formula can achieve both... After being applied to the blank, the bending strength is far superior to that of existing technologies. This allows the bending strength of the high-strength aluminum porcelain insulator to reach about 210 MPa after the head umbrella is dipped in glaze once, based on the blank bending strength of 170 MPa. This eliminates the need to separately glaze the head umbrella as in existing technologies to achieve a bending strength of over 200 MPa. This reduces the number of glazing equipment required, greatly reduces equipment procurement costs, and also greatly reduces the maintenance / repair costs of the glazing equipment. In addition, the single glazing of the head umbrella can greatly improve production efficiency.

[0020] Furthermore, the glaze used in this invention can also be used to glaze porcelain sand in subsequent processes. After coating the surface of the porcelain sand with glaze powder, it forms glazed sand. Finally, the glazed sand is applied to the inner and outer surfaces of the head of the suspended porcelain by sandblasting or sand filling. This allows the same glaze to be used for both the glazing of the head of the suspended porcelain and the treatment of the porcelain sand before sanding. This ensures that the bending strength of the suspended porcelain after glazing and sanding is increased to 220MPa-233MPa. This approach not only reduces costs but also achieves a breakthrough in the bending strength of the suspended porcelain. It also makes the resulting suspended porcelain smooth, flat, color-different, and has good wear resistance and corrosion resistance. Attached Figure Description

[0021] Figure 1 This is a flowchart of the one-time glazing process for the ultra-high pressure suspended porcelain head umbrella according to Embodiment 1 of the present invention.

[0022] Figure 2 This is a schematic diagram of the structure of the suspended porcelain umbrella during the first glazing process according to Embodiment 1 of the invention. Detailed Implementation

[0023] The following detailed description illustrates the specific implementation method: Example 1 Combination Figure 1 and Figure 2 A one-time glazing process for a special high-pressure suspended porcelain umbrella includes the following steps: S1. Glaze Preparation: The glaze is made from the following raw materials in parts by weight: 10-20 parts microcline, 10-20 parts albite, 5-15 parts highly plastic 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. All raw materials are mixed and then wet-milled. The resulting glaze slurry is sieved to remove iron using a 360-mesh sieve. The residual weight after sieving is 0.05%-0.18%. The cleaned glaze slurry is then poured into a glazing tank. During this process, the specific gravity of the glaze slurry is adjusted to achieve a specific gravity of 1.45-1.55 g / cm³. 3 For later use.

[0024] S2. Place the head of the spare blank onto the suction cup of the glazing machine (the suction cup adheres to the top of the blank). The glazing machine moves the suction cup and the upright blank into the glazing tank for one-time glazing of the head, so that the entire blank except for the top is immersed in the glaze. Before the blank is placed into the glazing tank, the agitator stirs the glaze in the glazing tank evenly and makes the glaze evenly suspended. During the glazing process, the glaze in the glazing tank is always in a flowing state. At the same time, a glazing spraying device is installed in the glazing tank. The glazing spraying device is located directly below the blank and is used to draw the glaze in the glazing tank and spray it onto the inner hole of the blank. The glazing requirements are: the glaze thickness is controlled at 0.25-0.60mm, and the glazing time is 5-7 seconds.

[0025] After the first glazing of the umbrella is completed, the glaze blank is removed and the glaze thickness of the head and umbrella part is measured. If the glaze thickness data meets the standard requirements, the glaze blank is put back on the shelf and protected with a film for subsequent sanding.

[0026] If the glaze thickness does not meet the standard, readjust the glaze slurry specific gravity or immersion time until the glaze thickness of the head and umbrella parts reaches the standard.

[0027] The chemical composition of the glaze used in the above process is as follows:

[0028] To verify the effect of sieving the glaze slurry on the single-stage glazing effect of the umbrella in this embodiment, test groups A to H below were used to verify the influence of the change in residual weight after sieving on the experimental results. Test groups A to H were identical except for the residual weight after sieving; the specific formula of the glaze used was: 15 parts microcline, 15 parts albite, 10 parts Ordos clay, 9 parts kaolin, 12 parts calcined talc, 7 parts wollastonite, 20 parts quartz powder, 8 parts zirconium silicate, and 4 parts alumina. Specific experimental data and conclusions are shown in Table 1. Table 1 - Experimental data and results of experimental groups A to H

[0029] As shown in Table 1, a lower residual weight after sieving through a 360-mesh sieve is more beneficial for improving the flexural strength of the glazed body after glazing. However, when the glaze particles in the glaze slurry are too fine (corresponding to test group E), the residual weight after sieving is extremely low. Although the flexural strength is high, it leads to glaze cracking. The presence of glaze cracking greatly increases the probability of contaminants remaining on the surface of the suspended porcelain, thereby increasing the probability of flashover and significantly reducing the quality of the suspended porcelain. It is not true that the finer the particles, the better. On the other hand, when the residual weight after sieving is too high, it indicates an increase in coarse particles in the glaze slurry. An increase in coarse particles not only fails to improve the flexural strength but also worsens the smoothness and thickness uniformity of the glaze surface. Therefore, controlling the residual weight of the glaze slurry after sieving is extremely crucial.

[0030] Example 2 Example 2 verifies the glaze used in Example 1 based on Example 1. Furthermore, to demonstrate that the glaze can be used for sandblasting after glazing the suspended porcelain, and that the suspended porcelain achieves a bending strength of 220-233 MPa after sandblasting, the following sandblasting process was performed on the suspended porcelain: 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 step, the mass ratio of porcelain sand to glaze powder is controlled at 1:(0.6 to 0.9).

[0031] II. While the porcelain sand and glaze powder are being stirred evenly, glue is added continuously. This allows the glue to coat the glaze powder onto the porcelain sand, forming a coated sand with an inner layer of porcelain sand, a middle layer mainly composed of glaze powder, and an outer layer mainly composed of glue (the glue in the outer layer will contain some glaze powder). This step yields coated sand with distinct, sticky particles coated with glaze. The particle size of the coated sand is 1.4–1.8 mm. During the preparation of the coated sand, the mass of the glue is 1 / 4 to 1 / 3 times the mass of the glaze powder.

[0032] After the glazing sand is prepared, the qualified glazing sand is put into a special container for later use to prevent moisture loss and the surface glue of the glazing sand from drying out, and to ensure that the glazing sand is in a sticky state.

[0033] III. Take the glazed blank from the first glazing of the umbrella head in Example 1, and brush the inside and outside of the head of the glazed blank with glaze-containing adhesive. The glaze-containing adhesive is an adhesive mixed with glaze slurry (glaze slurry after iron removal by sieving 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 in the first glazing of the umbrella head. The adhesive used in this step and the adhesive used in the glaze coating sand are both commonly used sanding adhesives in the industry, such as CMC adhesive. Then, the glaze coating sand is applied to the outer and inner surfaces of the head of the glazed blank by filling or sandblasting. In this step, the glaze coating sand itself is sticky, and the adhesive is also sticky, so that the glaze coating sand can be evenly adhered to the surface of the head of the glazed blank to obtain a glazed and sanded blank.

[0034] IV. The glazed and sand-coated blanks are placed in a drawer kiln for glazing and firing, and then cooled to room temperature to obtain high-grade suspended porcelain, which can be used in ultra-high voltage and even extra-high voltage power transmission projects.

[0035] Based on the above process, different raw material formulations yield different experimental results. The specific raw materials used in this embodiment are as follows: Microcline was selected from Shaanxi Province, and its main chemical analysis parameters are as follows:

[0036] The sodium feldspar used is from Linxiang, and its main chemical analysis indicators are as follows:

[0037] 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:

[0038] 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:

[0039] Calcined talc from Zichuan was used, and its main chemical analysis parameters are as follows:

[0040] The wollastonite used is from Luzhou, and its main chemical analysis parameters are as follows:

[0041] The quartz powder used is from Jiangxi Province, and its main chemical analysis control indicators are as follows:

[0042] Zirconium silicate using Huaan Zirconium silicate has the following key chemical control indicators:

[0043] The alumina used is Kaiyuan alumina, and its main chemical analysis control indicators are as follows:

[0044] Detailed experimental data and results are as follows: Table 2 - Comparative experimental data before and after changes in microcline dosage

[0045] Table 3 - Comparative experimental results before and after changes in microcline dosage

[0046] As can be seen from Tables 2 and 3, 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.

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

[0048] Table 5 - Comparative experimental results before and after changes in calcined talc dosage

[0049] As can be seen from Tables 4 and 5, 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.

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

[0051] Table 7 - Comparative experimental results before and after changes in wollastonite dosage

[0052] As shown in Tables 6 and 7, 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 decreases significantly and the high-temperature fluidity increases significantly, solving the problems of roughness and pinholes. However, this easily leads to glaze bubbles, which significantly reduces the wear resistance and corrosion resistance. Furthermore, 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.

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

[0054] Table 9 - Comparative experimental results before and after changes in quartz powder dosage

[0055] As shown in Tables 8 and 9, 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. Moreover, 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.

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

[0057] Table 11 - Comparative experimental results before and after changes in zirconium silicate dosage

[0058] As shown in Tables 10 and 11, 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.

[0059] 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.

[0060] 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.

[0061] 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. A one-time glazing process for a special high-pressure suspended porcelain umbrella, characterized in that, The steps include the following: S1. Prepare the glaze into a glaze slurry, wherein the glaze is made from 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 chemical composition of the glaze is: 60-72% SiO2, 14-17% Al2O3, less than 0.7% Fe2O3, 3.0-4.0% CaO, 3.0-5.0% MgO, 2.0-3.5% K2O, 1.5-3.0% Na2O, 4.0-7.0% ZrO2, and 3.5-7.0% Il, with a total chemical composition of 100%; S2. Place the head and umbrella part of the blank into the glaze slurry and use the glazing method to glaze the head and umbrella part of the blank in one go. The specific glazing method is as follows: The glaze slurry used for glazing is placed in the glazing tank. During glazing, the blank is placed upright, and a glazing spraying device is set below the blank. The glazing spraying device is used to draw the glaze slurry in the glazing tank and spray it onto the inner hole of the blank. The specific gravity of the glaze slurry is 1.45-1.55 g / cm³. 3 The glaze slurry is sieved through a 360-mesh sieve, and the residual weight after sieving is 0.05%-0.18%.

2. The one-time glazing process for the ultra-high pressure suspended ceramic head umbrella according to claim 1, characterized in that: The thickness of the glaze layer after the umbrella is 0.25-0.6mm after one glazing.

3. The one-time glazing process for the ultra-high pressure suspended porcelain head umbrella according to claim 1, characterized in that: The glazed blank is held in place by a suction cup at the top.

4. The one-time glazing process for the ultra-high pressure suspended porcelain head umbrella according to any one of claims 1-3, characterized in that: After the blank is dipped in glaze once, it is wrapped in a thin film.

5. The one-time glazing process for the ultra-high pressure suspended porcelain head umbrella according to any one of claims 1-3, characterized in that: The glazing process maintains the flow of glaze slurry relative to the blank.

6. The one-time glazing process for the ultra-high pressure suspended porcelain head umbrella according to claim 1, characterized in that: The calcined talc is 10-12 parts.

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