A method for calculating the optimal chain distance of scraper

Abstract

The present invention discloses a method for calculating the optimal chain distance of a scraper. According to the force analysis of the scraper, the knowledge learned from material mechanics is used to establish the scraper bending moment equation and draw a scraper bending moment distribution diagram; according to the scraper bending moment distribution diagram, the optimal chain distance equation of the scraper is established, that is, when the bending moment at the scraper chain is equal to the negative value of the middle bending moment of the scraper, the maximum bending moment of the scraper is the smallest, that is, the chain distance at this time is the optimal chain distance, and the optimal chain distance can be calculated according to this equation, and a maximum bending moment variation diagram of the scraper with different chain distances is drawn. The optimal chain distance calculated by the present invention is suitable for underground mining chute scraper transfer machines and open-air scraper conveyors. The use of this chain distance can minimize the stress state of the scraper, improve the safety factor of the scraper, and extend the service life of the scraper, which has great promotion and application value.

Description

Technical Field

[0001] The invention relates to the technical field of scraper conveyor design, in particular to a method for calculating an optimal chain distance of a scraper. Background Art

[0002] Scraper conveyors are widely used in the coal industry, including underground mines, open-pit mines, power plants, coal preparation plants, etc., and are responsible for the transportation and transfer of coal. Among them, the scraper chain, as an important component of the transmission system, is related to the operating efficiency of the scraper conveyor. In recent years, with the large-scale development of mining and transportation equipment, the trough width of the scraper conveyor has continued to increase, and the scraper has also been lengthened. However, the chain pitch of the middle double chain scraper remains basically unchanged, or some equipment blindly uses the side double chain, resulting in frequent bending or even breaking of the scraper, which seriously affects the efficiency of mine mining and transportation, and brings certain safety hazards to equipment and personnel. At present, there is no method for calculating the scraper chain pitch, so there are certain human factors in determining the scraper chain pitch, which belongs to the calculation blank area. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide a method for calculating the optimal chain distance of a scraper. The calculation method is simple and clear. The optimal chain distance of a scraper can be obtained by the calculation method. The optimal chain distance is a chain distance between the middle double chain and the side double chain, so the simple middle double chain or side double chain is not the best chain distance. The use of the optimal chain distance can reduce the stress state of the scraper to the minimum, increase the safety factor of the scraper, and extend the service life of the scraper, which has great promotion and application value.

[0004] The technical solution adopted by the present invention is: a method for calculating the optimal chain distance of a scraper, based on an assumption: during the normal operation of the scraper chain, the scraper is subjected to the pulling force of two chains and the resistance of the coal in front of the scraper, and the pulling force of the chain on the scraper is equal to the resistance of the coal; based on the coal quality state, it is assumed that the resistance of the coal to the scraper is uniformly distributed.

[0005] Furthermore, a method for calculating the optimal chain distance of a scraper comprises the following steps:

[0006] ① Draw a schematic diagram of the scraper force, such as Figure 1 shown.

[0007] ② According to the segment-by-segment analysis method, the bending moment equations of each segment of the scraper are listed.

[0008] ················(1)

[0009] ·····(2)

[0010] ·········(3)

[0011] In the formula,

[0012]

[0013]

[0014]

[0015]

[0016] in,

[0017] ③ According to the bending moment equation, draw the scraper bending moment distribution diagram, such as Figure 2 As shown. Figure 2 It can be seen that the bending moment is the largest at the chain distance. When the bending moment at the chain distance is equal to the absolute value of the bending moment at the middle position of the scraper, the maximum bending moment at this time is the smallest, that is, the stress state of the scraper is the best at this time, and the chain distance is optimal, as shown in the curve .

[0018] ④ Find the optimal chain distance of the scraper

[0019] From equation (1), we can get

[0020]

[0021] From equation (2), we can get

[0022]

[0023] make , can be obtained

[0024]

[0025] From the above formula, we can get , then the maximum bending moment equation of the scraper is

[0026] ···············(4)

[0027] ·················(5)

[0028] Plotting the above function, such as Figure 3 As shown. Figure 3 It can be seen that when the chain distance is less than When the chain distance is greater than When the chain distance is larger, the maximum bending moment is larger; when the chain distance is Value When , that is, the optimal chain distance of the scraper .

[0029] The present invention is reasonably and simply designed, and uses the knowledge of material mechanics to analyze and calculate the force on the scraper. The obtained optimal chain distance can reduce the stress state of the scraper to a minimum, extend the service life of the scraper, effectively reduce the equipment failure rate, and improve the mining and transportation efficiency of the mine.

[0030] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is the schematic diagram of the scraper force;

[0032] Figure 2 The bending moment distribution diagram of scraper with different chain distances;

[0033] Figure 3 The maximum bending moment variation diagram of scraper with different chain pitches; DETAILED DESCRIPTION

[0034] The essential contents of the present invention are further explained below in conjunction with examples:

[0035] Taking the SGZ1200 / 1000 conveyor for open-pit mine as an example, the scraper length , scraper chain distance , Rated tension of a single chain Assuming the motor is at full power and the chain tension acts on one scraper, the bending moment at the scraper chain distance can be obtained from equation (4): ; If the optimal chain distance of the scraper is adopted, the optimal chain distance is ,Depend on Figure 3 It can be known that the bending moment at the scraper chain distance , the maximum bending moment of the scraper is reduced by 71%.

[0036] It can be seen that by adopting the optimal chain distance, the stress state of the scraper will be greatly reduced.

Claims

1. A method for calculating the optimal chain distance of a scraper, characterized in that: During the normal operation of the scraper chain, the scraper is subjected to the pulling force of the two chains and the resistance of the coal in front of the scraper, and the pulling force of the chain on the scraper is equal to the resistance of the coal; according to the coal quality state, it is assumed that the resistance of the coal to the scraper is uniformly distributed; a method for calculating the optimal chain distance of the scraper includes the following steps: ①Draw a schematic diagram of the scraper force; ② According to the segment-by-segment analysis method, the bending moment equations of each segment of the scraper are listed: In the formula, L—scraper length, m l—scraper chain distance, m q—uniformly distributed load, KN / m F—chain tension, KN in, ③ According to the bending moment equation, draw the scraper bending moment distribution diagram. It can be seen from the scraper bending moment distribution diagram that the bending moment at the chain distance is the largest. When the bending moment at the chain distance is equal to the absolute value of the bending moment at the middle position of the scraper, the maximum bending moment at this time is the smallest, that is, the stress state of the scraper is the best at this time, and the chain distance is optimal, as shown in curve l4; ④ Find the optimal chain distance of the scraper From equation (1), we can get From equation (2), we can get Let M4 = -M'4, we can get From the above formula, we can get l = 0.586L, then the maximum bending moment equation of the scraper is: The above function is used to draw the maximum bending moment variation diagram of the scraper with different chain pitches. It can be seen from the maximum bending moment variation diagram of the scraper that when the chain pitch is less than 0.586L, the larger the chain pitch, the smaller the maximum bending moment; when the chain pitch is greater than 0.586L, the larger the chain pitch, the larger the maximum bending moment; when the chain pitch l is 0.586L, the maximum bending moment of the scraper has a minimum value M min =0.043F·L, that is, the optimal chain distance of the scraper is l=0.586L.

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