Coal sample preparation unit

Abstract

The invention provides a coal sample preparation unit, which relates to the field of coal sample preparation and comprises an automatic elevator, a variable-frequency feeding belt, a primary hammer type crushing mechanism, a first quantitative divider, a second quantitative divider, a fixed-mass divider and a control system, the primary hammer type crushing mechanism is used for primarily crushing coal, and the crushed coal is input into the first quantitative divider; coal output from a first division discharge port of the first quantitative division device is input into the double-roller crushing mechanism, and the double-roller crushing mechanism is used for performing secondary crushing on the divided materials; a waste material discharged from a first waste material outlet of the first quantitative divider is input into a second quantitative divider, and the second quantitative divider outputs a full-water sample; and the fixed mass divider is connected with the discharge end of the double-roller crushing mechanism. According to the weight of the raw coal sample, the division ratio is automatically adjusted, and the minimum sample reserving amount of general analysis coal samples, standby samples and total-moisture coal samples meets the national standard requirement.

Description

Technical Field

[0001] This invention relates to the field of coal sample preparation technology, and in particular to a coal sample preparation unit. Background Technology

[0002] Currently, the fuel sample preparation unit is an old-style fixed-ratio unit, which has the following problems.

[0003] 1. The crusher lacks a cleaning device and has poor moisture adaptability.

[0004] 2. The material is loaded manually, which is labor-intensive.

[0005] 3. The waste conveyor belt is located indoors, and the dust inside cannot be controlled, resulting in indoor air pollution, substandard environment, and harm to sample preparation personnel.

[0006] 4. For units that reduce samples to a fixed mass, the sample size is uncertain each time, requiring further manual reduction, which increases the labor intensity of personnel and the risk of contamination during sample preparation.

[0007] 5. The old unit's divider is a mechanical reciprocating divider. When the divider moves, it will knock some sample particles away, causing particle size segregation.

[0008] 6. The reduction ratio of the old unit is manually adjusted, and after each adjustment, it needs to be verified to ensure that the unit's precision and segregation are up to standard.

[0009] 7. The connections of components in the old unit are basically not sealed, resulting in a lot of dust during sample preparation and causing environmental pollution. Summary of the Invention

[0010] The present invention provides a coal sample preparation unit to solve at least one of the technical problems mentioned in the background art.

[0011] To solve the above-mentioned technical problems, the present invention discloses a coal sample preparation unit, comprising: Automatic hoists are used to transport coal; The variable frequency feeding belt is used to adjust the coal feeding rate at the discharge end of the automatic elevator. The primary hammer crusher is used to crush coal in the first stage. The coal is fed into the primary hammer crusher by the discharge end of the variable frequency feeding belt. The first quantitative divider is fed into the discharge end of the primary hammer crusher. The first quantitative divider is provided with a first waste outlet and a first divider discharge outlet. The coal output from the first reduction outlet is fed into the double roll crushing mechanism, which is used to perform secondary crushing on the reduced material. The waste discharged from the first waste outlet of the first quantitative reducer is input into the second quantitative reducer, and the second quantitative reducer outputs a total water sample. A fixed-mass sample divider, connected to the discharge end of the roller crushing mechanism, is used to prepare a fixed-mass sample. The control system is electrically connected to the automatic elevator, the variable frequency feeding belt, the primary hammer crusher, the double roller crusher, and the constant mass divider.

[0012] Preferably, the fixed-mass divider outputs 100g of 3mm sample and 700g of 3mm sample.

[0013] Preferably, the reduction ratio of the fixed-mass reducer is automatically adjusted online under the premise of no systematic deviation and satisfying the relationship between the sample quantity and particle size; The receiving hopper, waste hopper, and sample tube of the fixed mass divider are all made of stainless steel and feature a fully sealed design to prevent moisture loss and coal powder leakage. Preferably, the constant-mass divider can automatically adjust the dividing frequency, and the constant-mass divider vibrates as a whole when dividing coal to ensure that there is no material blockage.

[0014] Preferably, the opening size of the mass divider is at least three times the maximum nominal particle size of the coal sample; The inclination of the grid slots of the constant mass divider to the horizontal plane should be at least 60º, and the moving speed of the constant mass divider should be below 0.6m / s.

[0015] Preferably, the number of cuts for the synthesis of the specimen from all subsamples or subsamples after reduction should be no less than 60; and the cutting cycle of the subsequent cutter should not overlap with the cutting cycle of the previous cutter. The amount of sample retained after reduction meets the minimum sample quantity requirements for the corresponding particle size specified in GB 474 and GB / T 19494.2.

[0016] Preferably, the noise level during unloaded transport is no greater than 70 dB(A); during sample preparation, the noise level measured at a distance of 1 m from the edge of each transmission mechanism and 1.5 m below it is no greater than 85 dB(A). The sample preparation cycle is 5-15 minutes; the primary hammer crusher and double roll crusher are equipped with cleaning devices, and waste materials are placed outdoors.

[0017] Preferably, it further includes: a conveying test device, which determines the set conveying speed of the variable frequency feeding belt for the current batch of coal raw materials before batch sampling; a testing device is installed at this time. The testing device is not installed when batch sampling of the current batch of coal raw materials is being conducted. The conveying test device includes: The testing device includes: a horizontal plate, which is detachable below the breaker hammer on the inner wall of the primary hammer crusher. The horizontal plate is divided into several testing areas, and each testing area is equipped with a weighing device. Acquisition module: used to acquire the target feed flow range of the current batch of coal raw materials in the primary hammer crusher; First determining module: used to determine the target conveying speed range of the variable frequency feeding belt for the current batch of coal raw materials based on the acquisition results of the acquisition module; The first control module is used to control the operation of the variable frequency feeding belt, so that the actual conveying speed of the variable frequency feeding belt is different for the first conveying test of the current batch of coal raw materials. Each first conveying speed is conveyed for a preset time of one, and the weight of the current batch of coal raw materials discharged by the variable frequency feeding belt is detected for each preset time of one, so as to obtain the flow rate of the current batch of coal raw materials output by the variable frequency feeding belt per unit time corresponding to each first conveying speed. The second determining module is used to determine the secondary screening conveying speed based on the flow rate of the current batch of coal raw materials output by the frequency conversion feeding belt per unit time corresponding to each primary screening conveying speed. The second control module is used to control the actual conveying speed of the variable frequency feeding belt to the secondary screening conveying speed for the second conveying of the current batch of coal raw materials for testing. Each secondary screening conveying speed is conveyed for a preset duration of two. During each preset duration of two, the actual rotation speed of the primary hammer crusher is controlled to be the rated speed. When each preset duration of two ends and the primary hammer crusher is not crushing the coal, the detection device is controlled to detect and obtain the crushing effect evaluation value and diffusion effect evaluation value corresponding to each secondary screening conveying speed, and obtain the comprehensive crushing effect evaluation value. Screening module: Used to screen the smallest secondary screening value whose comprehensive crushing effect evaluation value is greater than the preset evaluation value. The conveying speed is the set conveying speed of the current batch of coal raw materials conveyed by the variable frequency feeding belt.

[0018] Preferably, the second determining module includes: Curve construction unit: used to construct a fitting curve of the flow rate of the current batch of coal raw materials output by the variable frequency feeding belt per unit time based on the flow rate of the current batch of coal raw materials output by the variable frequency feeding belt per unit time corresponding to each screening conveying speed; The division and determination of the unit is used to divide the fitting curve of the primary screening conveyor speed - the flow rate of the current batch of coal raw material output by the frequency conversion feeding belt per unit time into several curve segments. The difference between the maximum flow rate of the current batch of coal raw material output by the frequency conversion feeding belt per unit time and the minimum flow rate of the current batch of coal raw material output by the frequency conversion feeding belt per unit time in each curve segment is less than the preset flow rate difference. The median primary screening conveyor speed of each curve segment is determined as the secondary screening conveyor speed.

[0019] Preferably, the comprehensive crushing effect evaluation value corresponding to each secondary screening conveyor speed is calculated based on the following formula: ; This is the comprehensive crushing effect evaluation value corresponding to the i-th secondary conveying speed; , Evaluation weight one and evaluation weight two; M is the total number of detection regions. Let be the particle size qualification rate after the i-th secondary conveying speed is crushed by the primary hammer crusher. The value for evaluating the crushing effect at the i-th secondary conveying speed; The flow rate of the current batch of coal raw material output by the frequency conversion feeding belt per unit time corresponding to the i-th secondary conveying speed; t is the duration of the preset duration two; Let be the total weight of the coal falling to the j-th detection area at the i-th secondary conveying speed; when Within the preset range, then The value is 1, otherwise The value is 0; This is the evaluation value of the diffusion effect at the i-th secondary transport velocity.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: The fixed-mass divider supports automatic adjustment of the divider ratio. Combined with designs such as "opening size ≥ 3 times the maximum particle size of coal sample and grid inclination ≥ 60°", it ensures that there is no material blockage or sample spillage during the divider process. The number of coal sample cuts is ≥ 60 and the cycles do not overlap. It guarantees the uniformity of coal sample particle size and quality from the source, and ensures that the sample retention after divider strictly matches the GB474 and GB / T19494.2 standards, providing an accurate "sample basis" for coal quality testing (such as calorific value and ash content analysis).

[0021] From the automatic hoist feeding to the primary hammer crusher, roller crusher, quantitative reduction, and fixed-quality reduction, each stage is linked by a PLC system. The reduction ratio and frequency are dynamically adjusted according to the weight of the incoming material, adapting to a wide range of samples from 15-120kg. This achieves closed-loop control of "incoming material weight - reduction parameters - sample quality", ensuring consistent coal sample preparation accuracy under different working conditions (e.g., system coal sample loss <2%), meeting the core requirements of power plants and coal inspection agencies for "accurate reproduction of raw coal quality" in coal samples.

[0022] The fully automated design (automatic lifting and feeding, variable frequency speed control, and crushing and splitting linkage) eliminates manual intervention, completing sample preparation in 5-15 minutes, significantly outperforming traditional manual / semi-manual sample preparation efficiency. For high-frequency sample preparation scenarios such as power plants, it can significantly shorten sample preparation time, freeing up manpower for other processes.

[0023] It supports "automatic adjustment of reduction frequency and adaptation to different total sample volumes", and is compatible with the preparation of multiple specifications such as 6mm full water coal sample and 3mm storage sample. The crusher and reducer support cleaning and quick cleaning of the inspection window. It can stably prepare samples even for high ash and high viscosity coal types (such as lignite and bituminous coal) without clogging or sticking to the wall, and is suitable for industrial scenarios with complex coal types.

[0024] The fixed-mass reducer features a fully sealed structure (stainless steel receiving hopper and waste hopper, preventing moisture loss and coal powder leakage), and a cleaning device is added to the primary / double-roll crusher. The waste conveyor belt is externally mounted. These features optimize three aspects: coal sample moisture retention (ensuring the accuracy of full water sample testing), workshop dust pollution (reducing coal powder spillage), and equipment cleaning difficulty (the cleaning device reduces manual cleaning). This helps enterprises reduce environmental protection costs and improve the working environment of the sample preparation workshop.

[0025] The design of inspection doors / windows, maintenance platforms, and emergency observation doors makes the cleaning and maintenance of crusher components "visual and convenient." The high reliability and low failure rate of the fixed-mass divider, combined with noise control (≤70dB under no-load and ≤85dB under operation), not only reduces the intensity of operation and maintenance (such as reducing monthly troubleshooting time by 50%), but also protects the occupational health of workshop personnel and supports the long-term stable operation of the sample preparation unit.

[0026] The sample preparation precision, offset, sample retention amount, and particle size strictly comply with national standards such as GB474 and GB / T19494.2. From equipment design (opening and inclination of the fixed-mass divider) to sample preparation process (number of cuts and cycle), the entire chain meets the standardization requirements for coal testing. The sample preparation data is directly used in coal quality reports, avoiding testing disputes caused by non-compliant equipment. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of a coal sample preparation unit according to the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0030] Example 1: This invention provides a coal sample preparation unit, such as... Figure 1 As shown, it includes: Automatic hoists are used to transport coal and enable automatic feeding during sample preparation. The variable frequency feeding belt is used to adjust the coal feeding rate at the discharge end of the automatic elevator. The primary hammer crusher is used to crush coal in the first stage. The coal is fed into the primary hammer crusher by the discharge end of the variable frequency feeding belt. The first quantitative divider is fed into the discharge end of the primary hammer crusher. The first quantitative divider is provided with a first waste outlet and a first divider discharge outlet. The coal output from the first reduction outlet is fed into the double roll crushing mechanism, which is used to perform secondary crushing on the reduced material. The waste discharged from the first waste outlet of the first quantitative reducer is input into the second quantitative reducer, and the second quantitative reducer outputs a total water sample. A fixed-mass sample divider, connected to the discharge end of the roller crushing mechanism, is used to prepare a fixed-mass sample. The control system is electrically connected to the automatic elevator, the variable frequency feeding belt, the primary hammer crusher, the double roller crusher, and the constant mass divider.

[0031] Preferably, the fixed-mass divider outputs 100g of 3mm sample and 700g of 3mm sample.

[0032] Preferably, the fixed-mass divider should meet relevant standards, and the reduction ratio of the fixed-mass divider should be automatically adjusted online under the premise of no systematic deviation and meeting the relationship between the sample quantity and particle size. The fixed-mass divider has the characteristics of high reliability, low failure rate, convenient maintenance, high reduction accuracy, large reduction ratio adjustment range, and reliable operation.

[0033] The receiving hopper, waste hopper, and sample tube of the fixed-mass divider are all made of stainless steel (non-deformable, non-detachable, and non-adhesive). The structure adopts a fully sealed design to prevent moisture loss and coal powder leakage. During the divider process, there must be no sample spillage or coal blockage. Preferably, the constant-mass divider can automatically adjust the divider frequency to meet the requirement of consistent sample volume for different total sample sizes, ensuring that the sample quality meets the requirements. Divider ratio: automatically adjusted. The constant-mass divider vibrates as a whole during coal divider division to ensure no material blockage.

[0034] Preferably, the opening size of the fixed-mass divider is at least three times the maximum nominal particle size of the coal sample; the inclination of the grid of the fixed-mass divider to the horizontal plane is at least 60º; and the moving speed of the fixed-mass divider should be below 0.6 m / s.

[0035] Preferably, the number of cuts for the synthesis of the specimen from all subsamples or subsamples after reduction should be no less than 60; and the cutting cycle of the subsequent cutter should not overlap with the cutting cycle of the previous cutter. The amount of sample retained after reduction meets the minimum sample quantity requirements for the corresponding particle size specified in GB 474 and GB / T 19494.2.

[0036] Preferably, the noise level during unloaded transport is no greater than 70 dB(A); during sample preparation, the noise level measured at a distance of 1 m from the edge of each transmission mechanism and 1.5 m below it is no greater than 85 dB(A). The sample preparation cycle is 5-15 minutes; the primary hammer crusher and double roll crusher are equipped with cleaning devices, and waste materials are placed outdoors.

[0037] The equipment can accept samples weighing between 15-120kg. It automatically prepares one 1.25kg sample of 6mm total moisture coal (the above total moisture sample) and two 3mm samples, one 100g and one 700g.

[0038] The components, preparation procedures, preparation precision, and offset of the coal sample preparation unit of the present invention meet the requirements of relevant standards.

[0039] The coal sample preparation unit of the present invention has safety facilities and an openable and closable inspection door (or window), and provides sufficient maintenance space for easy inspection and maintenance.

[0040] The crusher cover should be openable for cleaning, and inspection windows should be installed at easily clogged areas such as the shrinking components and pipelines for inspection and cleaning. Other relevant locations should have maintenance platforms, passageways, and emergency observation doors to facilitate the inspection, maintenance, and replacement of individual equipment parts.

[0041] The coal sample preparation unit of this invention can automatically adjust the reduction ratio according to the weight of the incoming material to achieve fixed-quality reduction. It can ultimately prepare 6mm total moisture coal samples (≥1.25-1.7kg / sample) and 3mm storage coal samples (700g-1000g / sample; 100-120g / sample). The variation in the weight of the retained samples must not be less than the minimum retention amount for the corresponding particle size, and the particle size of the samples must meet the requirements. The coal sample loss of the system is less than 2%.

[0042] This invention constructs a PLC control system that automatically adjusts the reduction ratio based on the weight of the raw coal sample, so as to ensure that the minimum retention amount of general analytical coal samples, reference samples, and total moisture coal samples meets the national standard requirements.

[0043] Mechanical components: Based on the power plant sampling barrel, an automatic lifting device was designed to achieve automatic feeding; a waste conveyor belt was added; and a cleaning device was added to the crusher to prevent coal blockage and sample mixing.

[0044] The beneficial effects of the above technical solution are as follows: The fixed-mass divider supports automatic adjustment of the divider ratio. Combined with designs such as "opening size ≥ 3 times the maximum particle size of coal sample and grid inclination ≥ 60°", it ensures that there is no material blockage or sample spillage during the divider process. The number of coal sample cuts is ≥ 60 and the cycles do not overlap. It guarantees the uniformity of coal sample particle size and quality from the source, and ensures that the sample retention after divider strictly matches the GB474 and GB / T19494.2 standards, providing an accurate "sample basis" for coal quality testing (such as calorific value and ash content analysis).

[0045] From the automatic hoist feeding to the primary hammer crusher, roller crusher, quantitative reduction, and fixed-quality reduction, each stage is linked by a PLC system. The reduction ratio and frequency are dynamically adjusted according to the weight of the incoming material, adapting to a wide range of samples from 15-120kg. This achieves closed-loop control of "incoming material weight - reduction parameters - sample quality", ensuring consistent coal sample preparation accuracy under different working conditions (e.g., system coal sample loss <2%), meeting the core requirements of power plants and coal inspection agencies for "accurate reproduction of raw coal quality" in coal samples.

[0046] The fully automated design (automatic lifting and feeding, variable frequency speed control, and crushing and splitting linkage) eliminates manual intervention, completing sample preparation in 5-15 minutes, significantly outperforming traditional manual / semi-manual sample preparation efficiency. For high-frequency sample preparation scenarios such as power plants, it can significantly shorten sample preparation time, freeing up manpower for other processes.

[0047] It supports "automatic adjustment of reduction frequency and adaptation to different total sample volumes", and is compatible with the preparation of multiple specifications such as 6mm full water coal sample and 3mm storage sample. The crusher and reducer support cleaning and quick cleaning of the inspection window. It can stably prepare samples even for high ash and high viscosity coal types (such as lignite and bituminous coal) without clogging or sticking to the wall, and is suitable for industrial scenarios with complex coal types.

[0048] The fixed-mass reducer features a fully sealed structure (stainless steel receiving hopper and waste hopper, preventing moisture loss and coal powder leakage), and a cleaning device is added to the primary / double-roll crusher. The waste conveyor belt is externally mounted. These features optimize three aspects: coal sample moisture retention (ensuring the accuracy of full water sample testing), workshop dust pollution (reducing coal powder spillage), and equipment cleaning difficulty (the cleaning device reduces manual cleaning). This helps enterprises reduce environmental protection costs and improve the working environment of the sample preparation workshop.

[0049] The design of inspection doors / windows, maintenance platforms, and emergency observation doors makes the cleaning and maintenance of crusher components "visual and convenient." The high reliability and low failure rate of the fixed-mass divider, combined with noise control (≤70dB under no-load and ≤85dB under operation), not only reduces the intensity of operation and maintenance (such as reducing monthly troubleshooting time by 50%), but also protects the occupational health of workshop personnel and supports the long-term stable operation of the sample preparation unit.

[0050] The sample preparation precision, offset, sample retention amount, and particle size strictly comply with national standards such as GB474 and GB / T19494.2. From equipment design (opening and inclination of the fixed-mass divider) to sample preparation process (number of cuts and cycle), the entire chain meets the standardization requirements for coal testing. The sample preparation data is directly used in coal quality reports, avoiding testing disputes caused by non-compliant equipment.

[0051] Example 2, based on Example 1, further includes: a conveying test device. Before batch sampling of the current batch of coal raw materials, the conveying test device determines the set conveying speed of the variable frequency feeding belt for conveying the current batch of coal raw materials. A testing device is installed at this time. When batch sampling of the current batch of coal raw materials is performed, the testing device is not installed. The conveying test device includes: The testing device includes: a horizontal plate, which is detachable below the breaker hammer on the inner wall of the primary hammer crusher. The horizontal plate is divided into several testing areas, and each testing area is equipped with a weighing device. Acquisition module: used to acquire the target feed flow range of the current batch of coal raw materials in the primary hammer crusher (determined based on the crushing capacity of the primary hammer crusher, the scaling capacity of the first quantitative divider, etc.). First determining module: used to determine the target conveying speed range of the variable frequency feeding belt for the current batch of coal raw materials based on the acquisition result of the acquisition module (the conveying speed is screened once from the target conveying range according to the preset speed interval (which can be an integer conveying speed), and the second screening speed is further screened from the first screening speed). The first control module is used to control the operation of the variable frequency feeding belt, so that the actual conveying speed of the variable frequency feeding belt is different for the first conveying test of the current batch of coal raw materials. Each first conveying speed is conveyed for a preset duration of one (less than the preset duration of two, which can be 10S-20S). The weight of the current batch of coal raw materials discharged by the variable frequency feeding belt is detected for each preset duration of one, and the flow rate of the current batch of coal raw materials output by the variable frequency feeding belt per unit time corresponding to each first conveying speed is obtained. The second determining module is used to determine the secondary screening conveying speed based on the flow rate of the current batch of coal raw materials output by the frequency conversion feeding belt per unit time corresponding to each primary screening conveying speed. The second control module is used to control the actual conveying speed of the variable frequency feeding belt to the secondary screening conveying speed for the second conveying of the current batch of coal raw materials for testing. Each secondary screening conveying speed has a preset conveying time of two (which can be 30S-50S). During each preset time of two, the actual rotation speed of the primary hammer crusher is controlled to be the rated speed. When each preset time of two ends and the primary hammer crusher is not crushing the coal, the detection device is controlled to detect and obtain the crushing effect evaluation value and diffusion effect evaluation value corresponding to each secondary screening conveying speed, and obtain the comprehensive crushing effect evaluation value. Screening module: Used to screen the smallest secondary screening value whose comprehensive crushing effect evaluation value is greater than the preset evaluation value. The conveying speed is the set conveying speed of the current batch of coal raw materials conveyed by the variable frequency feeding belt.

[0052] Preferably, the second determining module includes: Curve construction unit: used to construct a fitting curve of the flow rate of the current batch of coal raw materials output by the variable frequency feeding belt per unit time based on the flow rate of the current batch of coal raw materials output by the variable frequency feeding belt per unit time corresponding to each screening conveying speed; The division and determination of the unit is used to divide the fitting curve of the primary screening conveyor speed - the flow rate of the current batch of coal raw material output by the frequency conversion feeding belt per unit time into several curve segments. The difference between the maximum flow rate of the current batch of coal raw material output by the frequency conversion feeding belt per unit time and the minimum flow rate of the current batch of coal raw material output by the frequency conversion feeding belt per unit time in each curve segment is less than the preset flow rate difference. The median primary screening conveyor speed of each curve segment is determined as the secondary screening conveyor speed.

[0053] Preferably, the comprehensive crushing effect evaluation value corresponding to each secondary screening conveyor speed is calculated based on the following formula: ; This is the comprehensive crushing effect evaluation value corresponding to the i-th secondary conveying speed; , Evaluation weight 1 and evaluation weight 2 (both with values ​​greater than 0 and less than 1, such as 0.6 and 0.4 respectively); M is the total number of detection regions (e.g., 3-5). Let be the particle size qualification rate after the i-th secondary conveying speed is crushed by the primary hammer crusher. The value for evaluating the crushing effect at the i-th secondary conveying speed; The flow rate of the current batch of coal raw material output by the frequency conversion feeding belt per unit time corresponding to the i-th secondary conveying speed; t is the duration of the preset duration two; Let be the total weight of the coal falling to the j-th detection area at the i-th secondary conveying speed; when Within the preset range, then The value is 1, otherwise The value is 0; This is the evaluation value of the diffusion effect at the i-th secondary transport velocity.

[0054] The beneficial effects of the above technical solution are as follows: By using the "conveying speed-comprehensive crushing effect evaluation value", the "particle size qualification rate" and "diffusion uniformity" under different belt speeds are quantitatively evaluated to ensure that the particle size and distribution of the crushed coal sample meet the testing requirements.

[0055] Adapting to coal quality differences: Customized testing for the "current batch of coal raw materials" can dynamically adapt to the hardness, particle size, and moisture content of different batches of coal, avoiding fluctuations in crushing effect caused by fixed parameters (e.g., high-moisture coal requires reduced conveying speed to prevent blockage, while low-hardness coal can increase speed and improve efficiency).

[0056] Before formal sample preparation, speed-effect matching is completed through a "conveyor testing device" to avoid repeated adjustments due to improper parameters during formal production. Based on the grading speed optimization of "primary screening-secondary screening," the belt speed is matched with the crushing mechanism's capacity, reducing material accumulation / idling (e.g., when the hammer crusher is running at full load, the belt speed is just right for feeding, increasing the sample production per unit time). When the crushing effect meets the standard, coal sample particles are less likely to fly away or be over-crushed, reducing dust in the workshop; at the same time, energy waste caused by ineffective crushing is avoided (e.g., hammer crusher idling or overloading).

[0057] Reduced labor costs: Pre-testing and automated control replace manual experience-based debugging, reducing the labor intensity of sample preparation personnel.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coal sample preparation unit, characterized in that, include: Automatic hoists are used to transport coal; The variable frequency feeding belt is used to adjust the coal feeding rate at the discharge end of the automatic elevator. The primary hammer crusher is used to crush coal in the first stage. The coal is fed into the primary hammer crusher by the discharge end of the variable frequency feeding belt. The first quantitative divider is fed into the discharge end of the primary hammer crusher. The first quantitative divider is provided with a first waste outlet and a first divider discharge outlet. The coal output from the first reduction outlet is fed into the double roll crushing mechanism, which is used to perform secondary crushing on the reduced material. The waste material discharged from the first waste outlet of the first quantitative reducer is input into the second quantitative reducer, and the second quantitative reducer outputs a total water sample. A fixed-mass sample divider, connected to the discharge end of the roller crushing mechanism, is used to prepare a fixed-mass sample. The control system is electrically connected to the automatic elevator, the frequency conversion feeding belt, the primary hammer crusher, the double roll crusher, and the constant mass divider.

2. The coal sample preparation unit according to claim 1, characterized in that, The fixed-mass divider outputs 100g of 3mm sample and 700g of 3mm sample.

3. A coal sample preparation unit according to claim 1, characterized in that, The reduction ratio of the constant mass fractionator can be automatically adjusted online under the premise of no systematic deviation and satisfying the relationship between the sample quantity and particle size. The receiving hopper, waste hopper, and sample tube of the fixed-mass divider are all made of stainless steel and feature a fully sealed design to prevent moisture loss and coal powder leakage.

4. A coal sample preparation unit according to claim 1, characterized in that, The constant-mass divider can automatically adjust the dividing frequency. When dividing coal, the constant-mass divider vibrates as a whole to ensure that there is no material blockage.

5. A coal sample preparation unit according to claim 1, characterized in that, The opening size of the fixed-mass divider should be at least three times the maximum nominal particle size of the coal sample; The inclination of the grid slots of the constant mass divider to the horizontal plane should be at least 60º, and the moving speed of the constant mass divider should be below 0.6m / s.

6. A coal sample preparation unit according to claim 1, characterized in that, The number of cuts for the synthesis of a specimen from all subsamples or subsamples after reduction should not be less than 60; and the cutting cycle of the subsequent cutter should not overlap with the cutting cycle of the previous cutter. The amount of sample retained after reduction meets the minimum sample quantity requirements for the corresponding particle size specified in GB 474 and GB / T 19494.

2.

7. A coal sample preparation unit according to claim 1, characterized in that, When unloaded, the noise level shall not exceed 70 dB(A); during sample preparation, the noise level measured at a distance of 1 m from the edge of each transmission mechanism and 1.5 m below it shall not exceed 85 dB(A). The sample preparation cycle is 5-15 minutes; the primary hammer crusher and double roll crusher are equipped with cleaning devices, and waste materials are placed outdoors.

8. A coal sample preparation unit according to claim 1, characterized in that, Also includes: Before batch sampling of the current batch of coal raw materials, the conveying test device first determines the set conveying speed of the variable frequency feeding belt for conveying the current batch of coal raw materials. At this time, the testing device is installed. When preparing samples of the current batch of coal raw materials in batches, no testing device is installed; The delivery test device includes: The testing device includes: a horizontal plate, which is detachable below the breaker hammer on the inner wall of the primary hammer crusher. The horizontal plate is divided into several testing areas, and each testing area is equipped with a weighing device. Acquisition module: used to acquire the target feed flow range of the current batch of coal raw materials in the primary hammer crusher; First determining module: used to determine the target conveying speed range of the variable frequency feeding belt for the current batch of coal raw materials based on the acquisition results of the acquisition module; The first control module is used to control the operation of the variable frequency feeding belt, so that the actual conveying speed of the variable frequency feeding belt is different for the first conveying test of the current batch of coal raw materials. Each first conveying speed is conveyed for a preset time of one, and the weight of the current batch of coal raw materials discharged by the variable frequency feeding belt is detected for each preset time of one, so as to obtain the flow rate of the current batch of coal raw materials output by the variable frequency feeding belt per unit time corresponding to each first conveying speed. The second determining module is used to determine the secondary screening conveying speed based on the flow rate of the current batch of coal raw materials output by the frequency conversion feeding belt per unit time corresponding to each primary screening conveying speed. The second control module is used to control the actual conveying speed of the variable frequency feeding belt to the secondary screening conveying speed for the second conveying of the current batch of coal raw materials for testing. Each secondary screening conveying speed is conveyed for a preset duration of two. During each preset duration of two, the actual rotation speed of the primary hammer crusher is controlled to be the rated speed. When each preset duration of two ends and the primary hammer crusher is not crushing the coal, the detection device is controlled to detect and obtain the crushing effect evaluation value and diffusion effect evaluation value corresponding to each secondary screening conveying speed, and obtain the comprehensive crushing effect evaluation value. Screening module: Used to screen the smallest secondary screening value whose comprehensive crushing effect evaluation value is greater than the preset evaluation value. The conveying speed is the set conveying speed of the current batch of coal raw materials conveyed by the variable frequency feeding belt.

9. A coal sample preparation unit according to claim 8, characterized in that, The second determining module includes: Curve construction unit: used to construct a fitting curve of the flow rate of the current batch of coal raw materials output by the variable frequency feeding belt per unit time based on the flow rate of the current batch of coal raw materials output by the variable frequency feeding belt per unit time corresponding to each screening conveying speed; The division and determination of the unit is used to divide the fitting curve of the primary screening conveyor speed - the flow rate of the current batch of coal raw material output by the frequency conversion feeding belt per unit time into several curve segments. The difference between the maximum flow rate of the current batch of coal raw material output by the frequency conversion feeding belt per unit time and the minimum flow rate of the current batch of coal raw material output by the frequency conversion feeding belt per unit time in each curve segment is less than the preset flow rate difference. The median primary screening conveyor speed of each curve segment is determined as the secondary screening conveyor speed.

10. A coal sample preparation unit according to claim 8, characterized in that, The comprehensive crushing effect evaluation value corresponding to each secondary screening conveyor speed is calculated based on the following formula: ； This is the comprehensive crushing effect evaluation value corresponding to the i-th secondary conveying speed; , Evaluation weight one and evaluation weight two; M is the total number of detection regions. Let be the particle size qualification rate after the i-th secondary conveying speed is crushed by the primary hammer crusher. The value for evaluating the crushing effect at the i-th secondary conveying speed; The flow rate of the current batch of coal raw material output by the frequency conversion feeding belt per unit time corresponding to the i-th secondary conveying speed; t is the duration of the preset duration two; Let be the total weight of the coal falling to the j-th detection area at the i-th secondary conveying speed; when Within the preset range, then The value is 1, otherwise The value is 0; This is the evaluation value of the diffusion effect at the i-th secondary transport velocity.

Images