What are the methods for self-inspection and calibration of sand and gravel standard sieves?

I am not a professional in this field, but I also want to understand and learn* one time.

It took me half a day to find it! Moderator please give me more wealth and charm! ! ! Haha★★The verification method is as follows: 1. Conduct appearance and data inspection of the standard sieve according to technical requirements. 2. Use a vernier caliper to measure the inner diameter of the screen frame. 3. Sand, gravel or pebble test sieve for ordinary concrete 5mm4pt] Use a vernier caliper to measure the size of the sieve holes above. The number of test holes should be no less than 20% of the total number. Use a graduated magnifying glass to detect sieve holes of 5mm and below. The number of test holes should be no less than 40. For round-hole sieves, the diameter deviation value is calculated based on the difference between a single measured value and the sieve hole diameter. For square-hole sieves, the maximum deviation between a single measured value and the sieve hole size is the maximum deviation, and the deviation between the average value of 40 measured values ​​and the sieve hole size is the average deviation. 4. For construction sand, gravel or pebble test sieves, use a vernier caliper to measure the size of the sieve holes above 4.75mm. The number of holes should be no less than 20% of the total number. Use a graduated magnifying glass to detect sieve holes of 4.75mm and below. The number of holes should be at least 40. The maximum and minimum values ​​among various apertures represent the deviation range of the corresponding aperture. This post was last edited by Lai Lai on 2009-3-24 22:36 ]

The following is the full content of the standard: Sand and gravel standard screen self-inspection and calibration method ZML-011 1. Technical requirements 1. Neat appearance, with model, specifications and manufacturer. 2. The screen frame is flat and smooth, and can be easily stacked with other screens, covers, material receiving barrels, etc. with the same basic size of the screen frame. The connection between the screen mesh and the screen frame can prevent leakage of materials to be screened. 3. The inner diameter of the screen frame is 300±5mm, or 200±5mm. 4. The hole diameter of the round hole sieve for sand, gravel or pebble test sieve for ordinary concrete should comply with the requirements in the following table: Sieve hole diameter W (mm) Diameter deviation (mm) Sieve hole diameter W (mm) Diameter deviation (mm) 100±0.8125.0±0.3580±0.7120.0±0. 3063±0.6116.0±0.2550±0.5310.0±0.2140±0.465.0±0.1431.5±0.402.5±0.11 5. The mesh size and deviation of square hole sieves for sand, gravel or pebble test sieves for ordinary concrete should comply with the requirements in the following table: Screen hole diameter W (mm) Screen hole allowable deviation (mm) Average deviation (2) The average size of the square hole screen holes shall not be larger than W+Y and shall not be smaller than WY. 6. The mesh size and deviation of the sand square hole screen for construction should comply with the requirements in the following table: Screen hole size (mm) Allowable deviation (mm) Screen hole size (mm) Allowable deviation (mm) 9.5±0.300.6±0.0214.75±0.150.3±0.0122.36±0.080.15±0.0061.18±0.040.075±0.004 7. The mesh size and deviation of the square hole screen for gravel and pebbles used in construction should comply with the requirements in the table below: Screen hole size (mm) Allowable deviation (mm) Screen hole size (mm) Allowable deviation (mm) 90±0.8026.5±0.3575±0.7019.5±0.276 3±0.6016±0.2153±0.559.5±0.1437.5±0.454.75±0.00431.5±0.402.36±0.11 2. Calibration items and conditions 1. Calibration items (1) Appearance (2) Inner diameter of sieve frame (3) Sieve hole size 2. Inspection instruments (1) Scale magnifying glass: The magnification is 40 times and the measurement accuracy is 0.01. (2) Vernier caliper: The measuring range is 300mm, and the graduation value is 0.02mm. (3) Steel ruler: The measuring range is 300mm, and the graduation value is 1.0mm. (4) Water: 20±5℃ 3. Calibration method 1. Check the appearance and data of the standard sieve according to the technical requirements. 2. Use a vernier caliper to measure the inner diameter of the screen frame. 3. Use a sand, gravel or pebble test sieve for ordinary concrete. Use a vernier caliper to measure the size of the sieve holes above 5mm. The number of test holes should be no less than 20% of the total number. Use a graduated magnifying glass to detect sieve holes of 5mm and below. The number of test holes should be at least 40. For round-hole sieves, the diameter deviation value is calculated based on the difference between a single measured value and the sieve hole diameter. For square-hole sieves, the maximum deviation between a single measured value and the sieve hole size is the maximum deviation, and the deviation between the average value of 40 measured values ​​and the sieve hole size is the average deviation. 4. For construction sand, gravel or pebble test sieves, use a vernier caliper to measure the size of the sieve holes above 4.75mm. The number of test holes should be no less than 20% of the total number. Use a graduated magnifying glass to detect sieve holes 4.75mm and below. The number of test holes should be at least 40. The maximum and minimum values ​​among various apertures represent the deviation range of the corresponding aperture. 4. Processing of verification results If all verification items meet the technical requirements, it is considered qualified. 5. Calibration period, records and certificates The calibration period should be determined according to the test needs and should not exceed 24 months. The calibration record format is shown in the table below, and the calibration certificate format is shown in Appendix I.

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1. The appearance is neat and tidy, with model, specification and manufacturer. 2. The screen frame is flat and smooth, and can be easily stacked with other screens, covers, material receiving barrels, etc. with the same basic size of the screen frame. The connection between the screen mesh and the screen frame can prevent the leakage of materials to be screened 3. The inner diameter of the screen frame is 300±5mm, or 200±5mm