This standard specifies the type and size, technical requirements, test methods, inspection rules, marking and packaging of wall bushings for electrostatic precipitators. This standard applies to DC rated voltage of 72kV, working temperature of positive 150℃, and installation location altitude not exceeding 1000m. This standard does not apply to working environments that are sufficient to reduce bushing performance and cause condensation on the surface of bushing porcelain parts. JB/T 6746.4-1993 Porcelain insulator wall bushings for electrostatic precipitators JB/T6746.4-1993 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Porcelain Insulators for Electrostatic Precipitators
Wall Bushings
Subject Content and Scope of Application
JB/T 6746.493
This standard specifies the types and dimensions, technical requirements, test methods, inspection rules, marking and packaging of wall bushings for electrostatic precipitators (hereinafter referred to as bushings).
This standard applies to bushings with a rated DC voltage of 72kV, an operating temperature not exceeding 150C, and an installation location with an altitude not exceeding 1000m. This standard does not apply to working environments that are sufficient to reduce the performance of the bushing and cause condensation on the surface of the bushing porcelain parts. 2 Reference Standards
JB/Z94
3 Terminology
Technical Conditions for High Voltage Insulator Porcelain Parts
Test Methods for Insulators
Electrical Terminology Insulators
Insulators Product packaging
The terms used in this standard conform to the provisions of GB2900.8. 4 Types and dimensions
4.1 The bushing shall be manufactured according to the drawings approved by the prescribed procedures. Its type and main dimensions shall conform to the provisions of Figure 1, Figure 2 and Table 1. L
Ministry of Machinery Industry·1993—08—21
Implementation on 1993-10—01
JTK-07201Abzxz.net
JTK-07202A
The bushing model is indicated as follows:
5 Technical requirements
JB/T6746.493
Table 1 Main dimensions of bushing
Indicates that the working temperature is 1 50℃
Product design sequence number·Use two-digit Arabic numerals to express the DC rated voltage: kv
Wall bushing for electrostatic precipitator (K represents glue-mounted structure) 5.1 The bushing should be made of heat-resistant porcelain material. Its appearance quality should comply with the relevant provisions of GB772. 5.2 The cross-section of the bushing porcelain should be homogeneous and dense, and there should be no penetration after the porosity test. The pressure during the porosity test shall not be less than 20MPa, and the product of pressure and time shall not be less than 180MPa·h. 5.3 The bushing shall withstand three rapid temperature changes without damage, and the test temperature difference shall comply with the relevant provisions of GB772. 5.4 The bushing shall be glued with a special high-temperature resistant adhesive, and the exposed surface of the adhesive shall be Flat. 5.5 The exposed surface of the metal accessories of the bushing shall be treated with anti-rust treatment; the screw hole shall be coated with anti-rust oil to prevent rust. 5.6 The electrical performance of the bushing shall comply with the following provisions. When the power frequency AC voltage is used instead of the DC voltage test, the qualified range of the power frequency voltage value is the DC voltage value divided by √2.
5.6.1 The bushing wall thickness breakdown voltage shall not be lower than the corresponding provisions of GB772. 5.6.2 The bushing shall withstand the 5min rated spark voltage test without breakdown, damage or abnormal heating, and its test voltage value shall comply with the corresponding provisions of GB772.
5.6.3 It shall withstand room temperature and high temperature DC withstand voltage test without breakdown, damage or flashover. The test value shall comply with the provisions of Table 2. When the power frequency AC voltage is used instead of the DC voltage test, the qualified range of the power frequency voltage value is the DC voltage value divided by √2. Table 2 Room temperature and high temperature DC withstand voltage
DC rated voltage
DC test voltage at room temperature
DC test voltage at 150℃
5.7 Within two years from the date of delivery, if the user finds that the bushing does not meet the requirements of this standard under the conditions of transportation, storage, installation and operation approved in accordance with the prescribed procedures, the manufacturer must replace it free of charge. 6 Test method
Except for the test methods specified in this standard, the rest shall be carried out in accordance with the corresponding provisions of GB775.1~775.2. 6.1 Room temperature and high temperature DC withstand voltage test The clean and dry test sample is installed in a closed device, and the shortest distance between the test sample and the high-voltage electrode and the inner wall of the device is not less than one times the dry flashover distance of the test sample. During the test, the test sample is placed in a vertical state and the voltage is applied between the two electrodes of the test sample. When testing at room temperature, the sample should maintain thermal equilibrium with the ambient temperature; when testing at high temperature, the sample should not be heated by direct baking, baking or other local heating methods, and the heating rate should not exceed 100℃/h.
When the temperature of each part in the device reaches the specified working temperature, apply voltage to the specified value and maintain for 1min. The sample should not be broken down, damaged or flashed, and the test is passed.
Inspection rules
The bushing is inspected by the quality inspection department of the manufacturer. The manufacturer should ensure that all the bushings delivered meet the requirements of this standard. 7.1
According to the inspection rules specified in this standard, the user has the right to inspect whether the quality and indicators of the bushing meet the requirements of this standard. 7.2
7.3 The bushing should be inspected in batches. The bushings of the same model manufactured by the same process method are considered as a batch, and the number of each batch shall not exceed 100. 7.4 The inspection of the bushing is divided into individual testing, sampling testing and type testing. 7.4.1 Test one by one
Test one by one in accordance with the provisions of Table 3. If any of the requirements specified in Table 3 are not met, the bushing shall be unqualified. Table 3 Test items one by one
7.4.2 Sampling test
Test item name
Appearance inspection
Dimension inspection
Work amount Spark voltage test
Test basis
Article 5.1 of this standard
Article 4.1 of this standard
Article 5.6.2 of this standard
Sampling test After the test is passed one by one, randomly sample 2 test pieces and conduct the test according to the provisions of Table 4. Table 4 Sampling test items
Test item name
Dimension inspection
Temperature cycling test
Porosity test
Test basis
Article 4.1 of this standard
Article 5.3 of this standard
Article 5.2 of this standard
Test quantity
All test pieces after item 1
Ceramic blocks after item 2
Test method
Test method
If two test pieces do not meet any requirement specified in Table 4 during the test, the batch of products shall be unqualified; if one product does not meet any requirement in any item, twice the number of test pieces shall be selected from the same batch of products for repeated testing. If there is still one test piece that does not meet any requirement in Table 4, the batch of casing shall be unqualified. However, if only the size inspection fails, only the size will be doubled. If it still fails, the manufacturer is allowed to select each one.
7.4.3 Type test
When a new product is trial-formed or the structure of a normal product is modified, the raw material formula and process method are changed, a type test must be carried out. The number of samples for type test shall not be less than 3, and after all tests are passed, the test shall be carried out according to Table 5. Table 5 Type test items
Test item name
Appearance inspection
Dimension inspection
Temperature cycle test
Wall thickness breakdown voltage test
Industrial spark voltage test
Room temperature and high temperature DC withstand voltage test
Pore acid test
Test basis
Article 5.1 of this standard
Article 4.1 of this standard
Article 5.3 of this standard
Article 5.6.1 of this standard|| tt||Article 5.6.2 of this standard
Article 5.6.3 of this standard
Article 5.2 of this standard
Test quantity (pieces)
All after item 1
All after item 2
1 after item 3
1 after item 3
1 after item 3
1 after item 3
After items 4 to 6, one piece of each porcelain block
When the type test is performed, if even one piece does not meet any of the requirements in Table 5, the type test is unqualified. 8 Marking and packaging
Test method
Article 6.1 of this standard
8.1 The casing should be packed in wooden boxes and ensure that it will not be damaged during transportation due to poor packaging. Its packaging shall refer to the corresponding provisions of JB/Z94. The packaging box should be marked with:
Manufacturer name;
Product model:
Product quantity;
Total weight of the packaging box:
“Handle with care”, “Porcelain parts” and other words or indication marks 8.2 The casing porcelain parts should have clear and firm manufacturer’s trademark and manufacturing year. 8.3
Each batch of bushings delivered shall be accompanied by a product certificate. This certificate shall bear the seal of the manufacturer's quality inspection department. Additional notes,
This standard was proposed by the National Technical Committee for Standardization of Insulators. It is under the jurisdiction of the Xi'an Electric Ceramics Research Institute, which is entrusted with the interpretation.
This standard was mainly drafted by Jiujiang Electric Ceramics Factory. This standard was mainly participated in by Tongchuan Electric Ceramics Motor Factory. This standard was mainly drafted by Liu Jisheng and Shu Guodong. This standard was mainly participated in by Li Dasen and Zhao Jincai. 24
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