This standard applies to the cleaning and grading of grains, oilseeds and seeds and the processing of grain, feed and other agricultural and sideline products. GB/T 3943-1983 Round hole and long hole sieve GB/T3943-1983 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Perforated plate with round and
elongated apertures
UDC621.928.2
GB3943-83
This standard applies to the cleaning and grading of grains, oilseeds and seeds and the processing machinery of grain, feed and other agricultural and sideline products. Types and basic dimensions
1.1 According to the shape and distribution of the sieve holes, the sieve plates can be divided into types Ia, Ib, Ⅱa, Ⅱb and Ⅱc. 1.1.1 Type I sieve plate: a round hole sieve plate, the center of the sieve hole is located at the vertex of an equilateral triangle, as shown in Figure 1. Issued by the National Bureau of Standards on November 24, 1983
Implemented on October 1, 1984
Rules for the arrangement of type Ia sieve holes
(One side is perpendicular to the direction of material movement) GB3943-83
Rules for the arrangement of type Ib sieve holes
(One side is parallel to the direction of material movement) Figure 1 Schematic diagram of sieve hole arrangement for type I sieve
Type Ia sieve: One side of the equilateral triangle formed by the center of the sieve holes is perpendicular to the direction of material movement. a.
b. Type Ib sieve: One side of the equilateral triangle formed by the center of the sieve holes is parallel to the direction of material movement. 1.1.2 Type II sieve-
Oval or rectangular sieve, the longitudinal center line of the sieve hole is parallel to the direction of material movement, as shown in Figure 2. a.
GB3943—83
Type Ⅱc
Figure 2 Schematic diagram of sieve hole arrangement of type Ⅱ sieve
Type Ⅱa sieve: oblong hole sieve, the sieve holes are staggered in the vertical and horizontal directions. Type b
Type ⅡIb sieve: oblong hole sieve, the sieve holes are arranged in a straight line in the horizontal direction and staggered in the vertical direction. Type Ⅱc sieve: rectangular hole sieve, the sieve holes are staggered in the vertical and horizontal directions. GB3943—83
1.2 The sieve number is represented by the basic size d of the sieve hole multiplied by 10. Note: The basic size d of the sieve hole: Type I sieve is the diameter of the sieve hole, and Type II sieve is the width of the sieve hole. Basic size of the sieve hole: Type I sieve should comply with the provisions of Table 1, and Type II sieve should comply with the provisions of Table 2. The main series shall be used first. 1.3
Screen hole diameter
Screen piece number
Main series
Sub series
I-type screen size
Basic size
*The screening area percentage is expressed as the percentage of the perforated area relative to the total effective area of ​​the screen surface. **The values ​​in column (7) correspond to the values ​​in column (5). Screening area percentage*
(calculated value)
<7) **
15，10
23，18
27，21
Sieve piece number
Sieve hole diameter d
Basic size
Sub-series
Main series
GB3943—83
Continued table 1
Hole spacing
Basic size
18，20Www.bzxZ.net
25，28
28，32
45，50
Screening area percentage Ratio*
(calculated value)
58，43
63，46
33，26
46，35
47，38
58 fold 48
58，46
58，47
Sieve number
Sieve hole width d
Basic size
Main series sub-series
Sieve hole length S
Basic size
) values ​​are special for rice milling machine sieves.
*Belt (
GB3943--83
Table 2 Type II sieve dimensions
Transverse hole spacing C
Basic dimensions
25(34)
（40）
**(The values ​​in the column 11 correspond to the values ​​in the column 7. Deviation
Longitudinal hole spacing K
Basic dimensions
Screening area percentage
(calculated value)
<11)**
21<15)
23<17)
24<18)||tt ||26<19)
27<20)
29<21)
30<22)
26<24)
27《25||tt ||30<29）
33(31)
35（33）
《13)
《19)
<20）
Sieve piece number
Sieve hole width d
Basic size
Main series sub-series
Sieve hole length S
Basic size
GB3943--83
Continued Table 2
Horizontal hole spacing C
Basic dimensions
Longitudinal hole spacing K
Basic dimensions
Screening area percentage
(calculated value)
<11)**
1.4For type I screen, type Ia should be used first. When the diameter d of the screen hole is less than 3mm, type Ib can be used in consideration of the processing technology.
1.5For type II screen, type IIa and IIb should be used first. When the width d of the screen hole is less than 3mm, type IIc can be used in consideration of the processing technology.
1.6For screen, steel plates with thickness of 0.5, 0.8, 1.0, 1.2, 1.5, 2.0, and 2.5 mm can be used first. According to the special requirements of use, steel plates of other thicknesses can also be used. 2 Technical requirements
2.1 Galvanized steel plates should be used to manufacture agricultural screening and grading screens. The technical requirements of the steel plates should comply with the provisions of YB180-63 "Technical conditions for galvanized thin steel plates". For screens that must be heat treated, appropriate materials can be selected according to process requirements. 2.2 Processing accuracy of screen holes: Type I screens should comply with the provisions of Table 1, and Type II screens should comply with the provisions of Table 2. 2.3 The basic dimensional deviation of the length L and width B of the screen should comply with the provisions of tolerance grade h14 in GB1804-79 "Tolerances and fits, limit deviations of dimensions without tolerances".
GB3943--83
2.4 The two diagonals of the screen should be equal, and their basic dimensions are the theoretical correct dimensions of the diagonals of the screen, and their dimensional deviations should comply with the provisions of tolerance grade h15 in GB1804.
2.5 The punching of the screen should be carried out from one side. There should be no burrs on the working surface of the screen. The burr height of the non-working surface: Type I screen shall not exceed 0.2mm, and Type II screen shall not exceed 0.3mm. Special requirements can be negotiated separately. 2.6 The working surface of the screen should be flat. Cracks, peeling, scars and rust are not allowed. There should be no breaks, continuous punching, punching failure and missed punching (when using multiple rows of punches: the second row of two opposite sides of Type Ib screen is allowed to be missed). 2.7 The screens of rice mills and crushers must be heat treated. Under the same conditions, the relative life of the heat-treated screen should be more than doubled that of the untreated screen. The technical requirements for heat treatment refer to Appendix A (reference). 2.8 The flatness of the plane screen or the roundness of the arc screen should not exceed the requirements of Table 3. Table 3
The outer dimensions of the arc screen are shown in Figure 3.
Schematic diagram of arc screen
2...1 The dimensional deviation of the opening width L of the finished product should not be greater than 2.9.2 The straightness of the two straight edges A and B:
GB3943-83
When the screen length L>160~250mm, the straightness should not be greater than 2.5mm; when the screen length L>250~400mm, the straightness should not be greater than 3mm. 2.9.3 The flatness of the plane formed by the two straight edges A and B is: when the screen length L>160~250mm, the flatness should not be greater than 4mm; when the screen length L>250~400mm, the flatness should not be greater than 5mm. 3 Inspection rules
3.1 The screen must be inspected and qualified by the technical inspection department of the manufacturer before it can leave the factory. 3.2 The ordering unit has the right to sample the finished products shipped from the factory according to the provisions of this standard. When sampling, if 10% of the packages (boxes) are randomly selected from each batch of finished products and the number is less than one package (box), it shall be sampled as one package (box). Then a certain proportion of screen pieces are sampled from each package (box), and the total number of screen pieces is 1% of the delivery quantity of each batch, but it shall not be less than 5 pieces. The inspection of the screen pieces shall be carried out in accordance with Chapter 2 of this standard. As for the inspection results, if there is one piece that is unqualified for each item in the technical requirements, double the number of screen pieces shall be sampled and the unqualified items shall be re-inspected. If there are still unqualified items in the re-inspection results, this batch of screen pieces may not be accepted. 3.3 Use visual inspection to find the maximum deviation of the sieve hole size and hole spacing, and take a length of not less than 100mm in the vertical and horizontal directions, but at least including 5 sieve holes, to inspect the diameter or width, length and hole spacing of the sieve holes. 3.4 The flatness or roundness of the sieve piece shall be inspected with a flat plate or an inner arc template. 3.4.1 For plane screens with a screen area equal to or greater than 0.5m2, select 8 points according to the provisions of Figure 4-a, press the screen against the flat plate with a weight (the contact area of ​​the pressure point is not greater than 2000mm2), and then measure the maximum gap. 3.4.2 For plane screens with a screen area less than 0.5m2, select 5 points according to the provisions of Figure 4-b, press the screen against the flat plate with a weight (the contact area of ​​the pressure point is not greater than 2000mm2), and measure the maximum gap. a
Figure 4 The position of the weight when testing the flatness of the plane screen b
3.4.3 The roundness of the arc screen is tested with the inner arc template. As shown in Figure 5, press the two ends and the center of the screen against the arc template and measure the maximum gap.
Pressure F
GB3943--83
Pressure F
Circular arc sample
Pressure F
Figure 5 Schematic diagram of circular arc screen roundness inspection
3.5 The straightness of the two straight sides A and B of the circular arc screen is inspected with a ruler. 3.6 The flatness of the surface formed by the two straight sides A and B of the circular arc screen is inspected with a flat plate. 3.7 Brittleness test: The circular arc screen after heat treatment is placed on the flat plate of the manual thread press, and a pressing plate greater than or equal to the unfolded area of ​​the screen is covered on the circular arc surface. Then the screw is slowly rotated to flatten the screen and take it out. Observe with the naked eye. No cracks should be generated on the inner and outer surfaces.
4 Marking and packaging
4.1 The screen leaving the factory must be accompanied by the manufacturer's quality inspection certificate. 4.2 The screen mark code and factory mark should be marked on the edge of the screen. 4.3 The packaging of the sieve should be firm and reliable, and should be able to prevent deformation and moisture. 4.4 The surface of the non-galvanized steel plate sieve should be rust-proof. 4.5 Each package should contain sieves of the same specification. If there are different sieves, it should be explained. The gross weight of each piece shall not exceed 80kg. The outside of the package should be marked:
a. Name, logo code and description:
b. Quantity;
Manufacturer name and factory number.
4.6 Screen marking code:
Screen number
Marking example
Length × width standard code
The Ia type round hole screen manufactured according to this standard with a screen hole diameter d of 6.5mm, a screen length L of 980mm, and a screen width B of 498mm is marked as:
980X498
GB3943—83
GB3943—83
Appendix A
Technical requirements for screen heat treatment
(reference)
A, 1 The heat treatment process of the screen is recommended to adopt carbonitriding, soft nitriding, and low-carbon martensitic treatment processes. The specific requirements are as follows: Carbonitriding process
Surface hardness: HV1kg>550
Depth of penetration layer: 70~170μm.
b. Soft nitriding process
Hardness of compound layer: HV≥450;
Depth of compound layer: 6~15um.
Metallurgical structure: A small amount of spot looseness is allowed on the surface within one-third of the depth of the compound layer. Low-carbon martensitic treatment process
Material: It is recommended to use B3 or 20 steel and other materials; Hardness: HRA>68, hardness test is carried out after 0.15mm is ground off the surface, metallurgical structure: the content of non-martensitic structure shall not exceed 5% of the whole structure. A.2
Export screens can be negotiated separately according to the trade contract and are not subject to this appendix. Additional notes:
This standard is proposed by the Ministry of Machinery Industry of the People's Republic of China and the Ministry of Commerce of the People's Republic of China, and is under the jurisdiction of the Chinese Academy of Agricultural Mechanization Sciences.
This standard was drafted by the Jiangxi Agricultural Machinery Research Institute and the Hubei Scientific Research and Design Institute of the Ministry of Food. From the date of implementation of this standard, the former agricultural machinery department standard N7-62 "Agricultural machinery round hole and oblong hole screens" will be invalid.
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