Anti-blocking control method for weighing belt conveyor of an automatic sampling system

Abstract

The present invention relates to a weighing belt conveyor anti-blocking control method for an automatic sampling system, comprising the steps of sampling, material transportation, weighing, etc. The weighing belt conveyor anti-blocking control method for an automatic sampling system provided by the present invention distributes the taken coal samples in a large area of ​​the weighing belt conveyor in a loose manner, thereby preventing material blockage.

Description

Technical Field

[0001] The present invention relates to a method for preventing blockage of a weighing belt conveyor in an automatic sampling system, belonging to the technical field of automatic control. Background Art

[0002] Coal is one of the main raw materials in industries such as metallurgy, electric power, and coal chemical industry. When materials enter the factory, sampling and inspection are required to determine whether the batch of materials meets the relevant procurement requirements. Generally, the transportation methods of incoming coal mainly include truck transportation, train transportation, and ship transportation, etc. Therefore, the corresponding coal unloading methods and sampling methods are also different. The relevant regulations in the national standard GB / T19494.1—2004 Mechanical Sampling of Coal: There are two major methods for coal sampling in the sampling method, namely moving coal stream sampling and stationary coal (train carriages, truck carriages, barges, etc.). At the same time, there are certain requirements for the number of sampling times (sub-samples) of each batch (ship, train) of incoming materials. Among them, moving coal stream sampling (belt transportation) is the most commonly used and simplest sampling method at present. Specifically, it is an automatic sampling system at the head of the belt. This system is generally built in a multi-story building (belt transfer station), and the equipment in each functional area is arranged in sequence using the height difference of different floors. Therefore, the drop is relatively large (basically more than 1.5m). Due to different coal unloading equipment and unloading methods in each enterprise, the coal flow situation on the main transportation belt is also different. For example, in ship unloader and train coal unloader, the coal flow on the main coal transportation belt is unstable, and coal peaks and coal valleys (no coal on the belt) often occur. Therefore, it is impossible to ensure that coal is sampled each time, resulting in the number of sampling times of incoming coal not meeting the national standard requirements, thus affecting the representativeness of the sampled test materials. Therefore, a weighing belt conveyor is added to the automatic sampling and sample preparation system to check whether coal is sampled in a single sampling and determine whether to supplement sampling in the automatic sampling and sample preparation system, increasing the representativeness of the test sample. When the belt conveyor weighs the mass of the sampled test material, the belt conveyor must be in a stationary state. When the upper-level belt conveyor drops the sampled wet coal from a high place (more than 1.5m) onto the weighing belt conveyor, the coal sample falls onto the belt at high speed under the influence of gravity acceleration and concentrates in a small area of the belt. After the weighing belt conveyor weighs and runs, the friction between the coal and the belt is less than the sum of the friction between the coal layer and the side plates on both sides and the resistance of the current-limiting plate. The belt runs forward, causing the coal layer to float above the belt, forming blockage. Especially for coal with high moisture content and high viscosity, it is more likely to be blocked. After each blockage, the system cannot sample normally, and it needs to be cleaned manually on site in time, otherwise it will affect the sampling of subsequent batches of incoming coal. According to the experience of the sampling machine manufacturer, when the moisture content of coal > 12%, it is not suitable to sample with an automatic sampling and sample preparation system with a weighing function, and blockage is likely to occur.

[0003] There are also relevant patents in the prior art introducing automatic sampling, mainly introducing the equipment structure, process, and function of the automatic sampling system, but they do not introduce specific measures and methods for preventing blockage. Therefore, there is an urgent need for a method for preventing blockage of a weighing belt conveyor to solve the above technical problems in order to sample completely according to the standard. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the above-mentioned technical drawbacks and provide a control method that can solve the problem of material blockage at the weighing belt conveyor in the head sampling system for coal with high moisture content and high viscosity, thereby reducing equipment failures, increasing equipment utilization rate, and improving the representativeness of the sampled specimens.

[0005] To solve the above technical problem, the technical solution proposed by the present invention is: a method for preventing blockage of a weighing belt conveyor in an automatic sampling system, comprising the following steps:

[0006] Step 1: When there is a material flow on the main coal conveyor belt and sampling can be performed; the sampling machine performs a full cross-section sampling operation on the material flow and pours the sampled sample into the discharge hopper;

[0007] Step 2: The vibrators of the material conveyor belt, the weighing belt conveyor, and the discharge hopper operate simultaneously until all the samples in the discharge hopper are unloaded onto the material conveyor belt;

[0008] Step 3: The material conveyor belt continues to operate, sending the sample to the feed opening and dropping it onto the weighing belt conveyor; as the sample gradually drops, the sample moves forward with the weighing belt conveyor. When it reaches t1, the weighing belt conveyor stops. At this time, the front end of the sample is 5 to 10 cm away from the feed opening of the weighing belt conveyor; when the material conveyor belt reaches t2, all the samples are sent to the feed opening and then it stops; where the running speed V 1 of the material conveyor belt 2 and the running speed V of the weighing belt conveyor satisfy the following relationship: 运 where 0.5 ≤ S ≤ 1.5, in the formula, t 1 is the effective running time of the material conveyor belt, that is, the time from when the sample starts to drop from the material conveyor belt onto the weighing belt conveyor to when all the samples drop from the material conveyor belt onto the weighing belt conveyor; L 称 is the effective running distance of the material conveyor belt, that is, the distance traveled by the material conveyor belt from when the sample starts to drop from the material conveyor belt onto the weighing belt conveyor to when all the samples drop from the material conveyor belt onto the weighing belt conveyor; t 2 is the running limit time of the weighing belt conveyor, that is, the time from when the sample starts to drop from the material conveyor belt onto the weighing belt conveyor to when the weighing belt conveyor stops; L

[0009] is the limit running distance of the weighing belt conveyor, that is, the distance traveled by the weighing belt conveyor from when the sample starts to drop from the material conveyor belt onto the weighing belt conveyor to when the weighing belt conveyor stops;

[0010] Step 4: The weighing belt conveyor weighs the coal sample taken this time;

[0011] The anti-blocking control method for the weighing belt conveyor of the automatic sampling system provided by the present invention distributes the sampled coal samples loosely over a large area of the weighing belt conveyor, making it less likely to block. The control method provided by the present invention is practical, easy to implement, and has good use effects; it solves the problem of material blockage in the weighing belt conveyor, can accurately obtain the weight information of each sampling, and the system can judge whether to supplement the sampling, so as to ensure the number of sub-samples taken for each batch of incoming materials, and ultimately ensure the representativeness of the sampled specimens and the composition detection data. It can be applied to the specimens required for the inspection of incoming materials with high moisture and high viscosity in other industries, and has good practical value and popularization value. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention will be further described below with reference to the accompanying drawings.

[0013] Figure 1 It is a schematic structural diagram of an automatic sampling system applying a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] Embodiment

[0015] The anti-blocking control method for the weighing belt conveyor of the automatic sampling system in this embodiment can be applied to an automatic sampling system as shown in Figure 1 The automatic sampling system includes: a material flow detector 1 arranged on the main conveyor belt, a head sampling machine 2, a discharge hopper 3 connected to the head sampling machine, a conveying belt conveyor 4 arranged below the discharge hopper 3, a chute pipe 7 arranged at the discharge opening of the conveying belt conveyor 4, and a weighing belt conveyor 10 arranged below the chute pipe 7; wherein vibrators 9 are installed on both the discharge hopper 3 and the chute pipe 7, a material flow shaping plate 5 is arranged on the conveying belt conveyor 4, a bulk material rod 6 is arranged in the chute pipe 7, and a material flow shaping plate 5 is also provided on the weighing belt conveyor 10, and a material pusher 8 is also installed; a chute pipe 7 is also arranged at the discharge opening of the weighing belt conveyor 10 to send the sample to the subsequent process.

[0016] The anti-blocking control method for the weighing belt conveyor of the automatic sampling system in this embodiment includes the following steps:

[0017] Step 1: When the material flow detector 1 detects that there is a material flow on the main coal conveyor belt and sampling can be carried out; the head sampling machine 2 performs a full cross-section sampling operation on the material flow and pours the sampled sample into the discharge hopper 3;

[0018] Step 2: The vibrators 9 and the material pusher 8 of the conveying belt conveyor 4, the weighing belt conveyor 10, and the discharge hopper 3 operate simultaneously until all the samples in the discharge hopper are unloaded onto the conveying belt conveyor; during the process, when the sample passes through the material flow shaping plate 5 on the conveying belt conveyor 4, it is leveled;

[0019] Step 3: The material conveying belt conveyor 4 continues to run, sending the sample to the feeding port and dropping it along the chute 7 onto the weighing belt conveyor 10; among them, the bulk material rod 6 can break up the sample; as the sample gradually drops, the sample moves forward with the weighing belt conveyor 10. When the weighing belt conveyor 10 runs to t1, the weighing belt conveyor 10 stops. At this time, the front end of the sample is 5 to 10 cm away from the feeding port 5 of the weighing belt conveyor 10; when the material conveying belt conveyor 4 runs to t2, all the sample is sent to the feeding port and then it stops; among them, the running speed V of the material conveying belt conveyor 1 and the running speed V of the weighing belt conveyor 2 satisfy the following relationship: where 0.5 ≤ S ≤ 1.5. In the formula, t 运 is the effective running time of the material conveying belt conveyor, that is, the time from when the sample starts to drop from the material conveying belt conveyor onto the weighing belt conveyor to when all the sample drops from the material conveying belt conveyor onto the weighing belt conveyor; L 1 is the effective running distance of the material conveying belt conveyor, that is, the distance the material conveying belt conveyor runs from when the sample starts to drop from the material conveying belt conveyor onto the weighing belt conveyor to when all the sample drops from the material conveying belt conveyor onto the weighing belt conveyor. t 称 is the limit running time of the weighing belt conveyor, that is, the time from when the sample starts to drop from the material conveying belt conveyor onto the weighing belt conveyor to when the weighing belt conveyor stops; L 2 is the limit running distance of the weighing belt conveyor, that is, the distance the weighing belt conveyor runs from when the sample starts to drop from the material conveying belt conveyor onto the weighing belt conveyor to when the weighing belt conveyor stops. Among them, according to the length relationship of L1 and L2 on site, select an appropriate S value, then set the speed of the material conveying belt conveyor or the weighing belt conveyor, and then calculate the speed of the other one according to the above relationship and set it.

[0020] According to the principle of material accumulation on the weighing belt conveyor and the structural characteristics of the weighing belt conveyor, the running speed of the weighing belt conveyor has a certain influence on material blockage. If the running speed of the weighing belt conveyor is too slow and the feeding amount of the material conveying belt conveyor is too large, material blockage will also occur. Therefore, controlling the speed ratio of the weighing belt conveyor and the material conveying belt conveyor within a certain range can prevent material blockage from occurring.

[0021] Since the distance (material running length) between the inlet feeding point and the outlet feeding point of the weighing belt conveyor and the material conveying belt conveyor is inconsistent, the speed ratio of the weighing belt conveyor and the material conveying belt conveyor can be controlled by calculation;

[0022] Step 4: The weighing belt conveyor 10 weighs the coal sample mined this time;

[0023] Step 5: After weighing is completed, send the sample to the subsequent process; start the weighing belt conveyor 10, the electric feeding device 8 and all the equipment at the rear end simultaneously. After the coal enters the vertical crusher 11 through the chute pipe and is crushed, it falls into the reduction belt conveyor 12. The crushed coal flow is reduced by the scraper splitter 13, and the reduced coal sample enters the sample collector 14 through the chute pipe 7; the unreduced coal sample enters the waste belt conveyor 15 through the chute pipe 7 for waste disposal.

[0024] The present invention is not limited to the above embodiments. Any technical solution formed by equivalent replacement falls within the protection scope required by the present invention.

Claims

1. A method for preventing blockage of a weighing belt conveyor in an automatic sampling system, the automatic sampling system comprising a material flow detector provided on a main conveyor belt, a head sampling machine, a discharge hopper connected to the head sampling machine, a material conveying belt conveyor arranged below the discharge hopper, a chute arranged at the material falling opening of the material conveying belt conveyor, and a weighing belt conveyor arranged below the chute, wherein vibrators are installed on both the discharge hopper and the chute; Characterized in that, it comprises the following steps: Step 1: When there is a material flow on the main coal conveyor belt and sampling can be carried out, the sampling machine performs a full cross-section sampling operation on the material flow and pours the sampled sample into the discharge hopper; Step 2: The vibrators of the material conveying belt conveyor, the weighing belt conveyor, and the discharge hopper operate simultaneously until all the samples in the discharge hopper are unloaded onto the material conveying belt conveyor; Step 3: The material conveying belt conveyor continues to operate, sending the sample to the material falling opening and dropping it onto the weighing belt conveyor; As the sample gradually falls, the sample moves forward with the weighing belt conveyor. When it reaches t1, the weighing belt conveyor stops. At this time, the front end of the sample is 5 to 10 cm away from the feeding opening of the weighing belt conveyor. When the material conveying belt conveyor reaches t2, the sample is completely sent to the feeding opening and then stops. Among them, the running speed V1 of the material conveying belt conveyor and the running speed V2 of the weighing belt conveyor satisfy the following relationship: S = t 运 / t 称 = , where 0.5 ≤ S ≤ 1.

5. In the formula, t 运 is the effective running time of the material conveying belt conveyor, that is, the time from when the sample starts to fall from the material conveying belt conveyor to the weighing belt conveyor until the sample completely falls from the material conveying belt conveyor to the weighing belt conveyor; L 1 is the effective distance of the material conveying belt conveyor, that is, the distance traveled by the material conveying belt conveyor from when the sample starts to fall from the material conveying belt conveyor to the weighing belt conveyor until the sample completely falls from the material conveying belt conveyor to the weighing belt conveyor; t 称 is the running limit time of the weighing belt conveyor, that is, the time from when the sample starts to fall from the material conveying belt conveyor to the weighing belt conveyor until the weighing belt conveyor stops; L 2 is the limit distance of the weighing belt conveyor, that is, the distance traveled by the weighing belt conveyor from when the sample starts to fall from the material conveying belt conveyor to the weighing belt conveyor until the weighing belt conveyor stops; Step 4: The weighing belt conveyor weighs the coal sample taken this time; Step 5: After weighing is completed, the weighing belt conveyor starts and sends the sample to the subsequent process.

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