This standard specifies the dimensions and deviations of conveyor belt width, length, total thickness and cover thickness and their measurement methods. The dimensions and deviations of total thickness and cover thickness and their measurement methods in this standard are not applicable to conveyor belts with metal cores. GB/T 4490-1994 Conveyor belt dimensions GB/T4490-1994 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Conveyor belts
Conveyor belts--Dimensions
GB/T 4490-94
Replaces GB 4490-84
This standard is equivalent to the international standards ISO251-1987 "Width and length of conveyor belts" and ISO583-1990 "Total thickness and cover thickness tolerance of fabric core conveyor belts (direct measurement method)". Subject content and scope of application
This standard specifies the dimensions and deviations of conveyor belt width, length, total thickness and cover thickness and their measurement methods. The dimensions and deviations of total thickness and cover thickness and the measurement methods in this standard are not applicable to conveyor belts with metal cores. 2 Reference standards
GB2941 Standard temperature, humidity and time for environmental conditioning and testing of rubber specimens GB/T5723 Determination of dimensions of specimens and products for testing vulcanized rubber and thermoplastic rubber 3 Width
3.1 Width and limit deviation
The width and limit deviation of the conveyor belt shall comply with the provisions of Table 1. Table 1
Conveyor belt width, mm
Limit deviation
Conveyor section width, mm
Note: The limit deviation of the conveyor belt width of 300 to 650 mm can also be negotiated by the supply and demand parties. 3.2 Measurement methodwww.bzxz.net
Limit deviation
The width of the conveyor belt is measured with a steel ruler with a measurement error of no more than 1 mm. Take 3 measurement values ​​for each dimension and take the median as the measurement result.
Instructions for use:
1] The note below Table 1 is added later and is not included in ISO 251-1987. Approved by the State Administration of Technical Supervision on December 22, 199442
Implemented on October 1, 1995
4 Length
4.1 Length and limit deviation
GB/T 4490-94
4.1.1 Conveyor belts are divided into two types according to their structural shapes: end belts and endless belts. Their length dimensions are determined by negotiation between the supplier and the buyer. 4.1.2 The length limit deviations of different types of conveyor belts shall comply with the provisions of Table 2. Table 2
Conveyor belt type
Annular belt
Ended belt
4.2 Measurement method
Conveyor belt length, m
>15～20
Composed of one section
Composed of several sections
Length of each section
Total length of each section
4.2.1 Measure with a steel ruler whose measurement error is not greater than 1mm. 4.2.2 Measurement of the length of the end belt
Lay the belt flat and in a loose state, and measure the belt length with a steel ruler. 4.2.3 Measurement of the circumference of annular belt
Limit deviation
±50mm
±75mm
Put the belt on a flat surface as shown in Figure 1, mark four points a, b, c, and d on the belt, and make ab-cd. After measuring the length of ab segment, lay down segments ac and d respectively and measure their lengths, and then calculate the central circumference (L) of the belt according to the following formula: Lp= 2ab + ac + bd
Figure 1 Length measurement of annular belt
Measure three times according to the above method, and take the median as the central circumference of the belt. Then calculate the inner circumference (L) of the belt according to formula (2). L, = L.
Where: L——Inner circumference of the belt, m,
Lp—Central circumference of the belt, m
d—Thickness of the belt, mm.
Note: This formula is applicable to plane conveyor belts with uniform and symmetrical cross-sections. 5 Cover thickness
5.1 Cover thickness and limit deviation
(2)
GB/T4490—94
The nominal value of the conveyor belt cover thickness shall be determined by negotiation between the supply and demand parties. The limit deviation of the conveyor belt cover thickness shall comply with the provisions of Table 3. Table 3
Nominal value of upper and lower cover thickness, mm
Upper deviation
Lower deviation
Upper deviation
Lower deviation
Limit deviation
Not specified
Not specified
5% of basic size
This regulation is only applicable to conveyor belts with a cover thickness greater than or equal to 1mm, and the cover must be completely peeled off during the test. 5.2 Measurement method
5.2.1 Temperature
The test room temperature shall be in accordance with GB2941 standard. 5.2.2 Measuring tools
The measuring tool is a rotating pointer thickness gauge that complies with the provisions of GB5723. The minimum scale spacing is not greater than 0.1mm, the diameter of the flat round measuring foot is 10mm, and the pressure applied by the measuring foot to the sample is 22±5kPa or 10±2kPa. 5.2.3 Sample
Cut a rectangular sample from the full-thickness fabric core conveyor belt. Its dimensions are as follows: a. Width: about 50mm,
b. Length: equal to the full width of the belt.
5.2.4 Procedure
5.2.4.1 Using the thickness gauge specified in 5.2.2, determine the total thickness d of the sample at the following number of measuring points (depending on the width b) in accordance with the provisions of Method A in GB5723:
a. b≤650 mm
b.650mm
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