scholarly journals Air Curtain Dust Removal Device Design and Dust Prevention Strategy in Heading Face

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Xu Huang
Keyword(s):  
Base Plate ◽  
Dust Concentration ◽  
Prevention Strategy ◽  
Previous Model ◽  
Dust Removal ◽  
Device Design ◽  
Airflow Velocity ◽  
Air Curtain ◽  
Total Dust ◽  
Left And Right

Dust protection is a safety guarantee of heading face. The previous model of air curtain research was ideal, and the dust removal effect was rarely studied in the actual dust-producing face. This paper presents a method of air curtain dust removal (ACDR) in the actual heading face. The author designed an air curtain dust removal device (ACDRD). The law of total dust concentration, respiratory dust concentration, and respiratory dust ratio is obtained. The minimum outlet airflow velocity is analyzed using the flat-plane injection theory. The effect of the exhaust fan placement on the dust removal effectiveness is examined. Research indicates the following: The airflow speed at the upper, left, and right sides of the ∩-shaped slot is 17.39 m/s, 12.04 m/s, and 13.66 m/s, respectively. The minimum dust removal speed of the air curtain is 5.48 m/s. The total dust concentration is the highest in the spot of roadheader operator, and the concentration of respiratory dust decreases sharply within 20 m. When the indentation air duct is 2.1 m away from the base plate, the dust-proof effect is better. The results can provide theoretical bases and methods for air curtain analysis of the heading face.

scholarly journals Experimental study of the dust-removal performance of a wet scrubber

2021 ◽  
Author(s):  
Shengyong Hu ◽  
Yang Gao ◽  
Guorui Feng ◽  
Fei Hu ◽  
Changhe Liu ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Water Intake ◽  
Dust Concentration ◽  
Dust Removal ◽  
Respirable Dust ◽  
Average Pressure ◽  
Total Dust ◽  
Air Volume ◽  
Wet Scrubbers ◽  
Wet Scrubber

AbstractA variety of dust control methods are often applied in coal mines, among which the application of wet scrubbers has proven to be an efficient technology for the removal of dust in airstreams, rather than diluting or confining the dust. In this paper, a wet scrubber design was developed. Based on a self-designed experimental test platform, the total dust concentration, respirable dust concentration, air volume, and average pressure drops of wet scrubbers with 12, 16, 20, and 24 blades were measured under different water intake conditions. The results show that the different water intake levels have only minimal effects on the air volume of the wet scrubbers. However, increased water intake had improved the dust removal efficiency of the wet scrubbers with the same number of blades. The wet scrubber with 16 blades was found to have the best dust removal efficiency at a water intake level of 1.35 m3/h. Its total dust and respirable dust removal efficiency reached 96.81% and 95.59%, respectively. The air volume was 200.4 m3/min, and the average pressure drop was determined to be 169.4 Pa. In addition, when the wet scrubber with 16 blades was applied in a coal preparation plant in China’s Shanxi Province, it was observed that the total dust concentration had fallen below 8.1 mg/m3, and the respirable dust concentration had fallen below 5.9 mg/m3. Therefore, the results obtained in this research investigation provide important references for the use of wet scrubbers to improve coal production environmental conditions.

scholarly journals CFD-Based Determination of the Optimal Blowing and Suction Air Volume Ratio of Dual-Radial Swirl Shielding Ventilation in a Fully Mechanized Excavation Face

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Kuan Wu ◽  
Shiliang Shi ◽  
Yijie Shi ◽  
Yong Chen
Keyword(s):  
Ventilation System ◽  
Volume Ratio ◽  
Simulation Method ◽  
Dust Concentration ◽  
Dust Control ◽  
Underground Mines ◽  
Physical And Mental Health ◽  
Control Effect ◽  
Air Curtain ◽  
Air Volume

Dust is one of the main pollutants in coal mines, which seriously affects the physical and mental health of workers, as well as the safe production in underground mines. Dual-radial swirl shielding ventilation is a new ventilation method for a fully mechanized excavation face and can effectively reduce the dust concentration in the underground. The dust control effect of dual-radial swirl shielding ventilation is mainly affected by the thickness and integrity of the shielding air curtain, as well as the disturbance of the flow field near the air curtain. By changing the blowing and suction air volume ratio of the air duct, the strength of the radial air curtain can be improved, and the dust control effect of the dual-radial swirl shielding ventilation system can be effectively improved. In order to determine the optimal operating parameters of the dual-radial swirl shielding ventilation system, a numerical simulation method was used to conduct an in-depth study on the blowing and suction air volume ratio of the system. The results showed that when the blowing and suction air volume ratio of the air duct was 1.5, the radial air curtain had the highest strength. Under this condition, the dust concentration at the driver’s position of the roadheader was the lowest, and the dual-radial swirl shielding ventilation system can achieve an ideal dust control effect.

scholarly journals Experimental Research and Numerical Simulation of Ejector Precipitator in a Fully Mechanized Mining Face

2020 ◽  
Vol 45 (11) ◽  
pp. 9815-9833
Author(s):  
Guodong Zhai ◽  
Wentao Zhang ◽  
Yaozong Li ◽  
Xinghao Lu ◽  
Wenyuan Hu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Negative Pressure ◽  
Coal Dust ◽  
Structural Parameters ◽  
Dust Concentration ◽  
Dust Removal ◽  
Measuring Point ◽  
Mining Face ◽  
Supply Water

AbstractIn order to effectively reduce the coal dust concentration in a fully mechanized mining face, this research used laboratory experiment, numerical simulation, and field test to conduct an in-depth exploration of the ejector precipitator installed at the low-level caving coal hydraulic support. Firstly, through the experimental platform in the laboratory, the dust removal effect of the nozzle with different structural parameters was tested, and the 3D particle dynamic analyzer was adopted to verify its atomization characteristics; then, the structural parameters corresponding to the nozzle in the best test results were obtained. Secondly, by using Fluent, the negative pressure flow field in the ejector barrel was numerically simulated. The results indicated that when the pressure of supply water was 12 MPa, the negative pressure value formed in the flow field was the lowest and the inspiratory velocity was the largest, which was conducive to dust removal. Finally, the tests of liquid–gas ratio and dust removal ratio were carried out in a fully mechanized mining face. The results showed that when the nozzle specification recommended by the experiment and the pressure of supply water recommended by the numerical simulation were used, the removal ratios of the total coal dust and the respirable coal dust were 89.5% and 91.0%, respectively, at the measuring point of the highest coal dust concentration. It indicates that the ejector precipitator has a good application effect in reducing the coal dust concentration in a fully mechanized mining face and improving the work environment of coal mine workers.

Respiratory Protection Provided by Negative Pressure Half Mask Filtering Respirators in Coal Mines

2018 ◽  
Vol 277 ◽  
pp. 232-240 ◽  
Author(s):  
Sergiy Cheberiachko ◽  
Olena Yavors’ka ◽  
Dmytro Radchuk ◽  
Andrii Yavorskyi
Keyword(s):  
Negative Pressure ◽  
Occupational Diseases ◽  
Coal Mines ◽  
Dust Concentration ◽  
Respiratory Protection ◽  
Breathing Zone ◽  
Sampling System ◽  
Total Dust ◽  
Exposure Limit ◽  
Low Efficiency

Two studies were conducted in the coal mines to evaluate worker exposures to a dust, and the effectiveness of air-purifying negative-pressure half mask respirators and was found that miners’ protection were insufficient. An elastomeric and filtering half-mask negative pressure respirators with (mid-efficiency) filters P2 (FFP2) were studied. Measurements of total dust concentrations in the in-mask and outer air were conducted simultaneously. Not identical sampling system led to an underestimation of the actual total inside dust concentration in the first study. The results have been corrected to reduce the systematic error. The inside total dust concentrations Ci exceeded national Permissible Exposure Limit (PEL) in most cases in both studies; in first GM Ci=24.7 mg/m3; in second 8.6 mg/m3. Protection factors were: from 2.9 to 6.9 in first study; and from 5.6 to 34 in second. Low efficiency of respirators can be caused by its non-continuous usage. High risk of miners’ occupational diseases should be reduced by decreasing the dust concentration in the breathing zone. It is advisable to check the possibility of improving respiratory protection of miners by powered air-purifying respirators.

Measuring the External Ear for Hearing Protection Device Design

2018 ◽  
Vol 26 (3) ◽  
pp. 4-8 ◽  
Author(s):  
Mohammad Amin Mououdi ◽  
Jafar Akbari ◽  
Maryam Mohammadi Khoshoei
Keyword(s):  
Measured Data ◽  
Anthropometric Measurements ◽  
Optimal Threshold ◽  
Hearing Protection ◽  
External Ear ◽  
Protection Device ◽  
Device Design ◽  
Protection Devices ◽  
Left And Right ◽  
The Mean

In this study we aimed to obtain anthropometric measurements of external ear dimensions for designing hearing protection devices (HPDs). We measured 3 dimensions of left and right ears of 153 operational workers and compared the measured data with earplugs (Eps) and earmuffs (Ems). The mean (± SD) earhole length, pinna length, and pinna width for the subjects were 14.6 (± 2.5), 62.8 (± 5.0), and 34.8 (± 4.2) mm, respectively. The mean longitudinal and transverse diameters of the Ems for the ear were close to the 95th and 97.5th percentile, respectively. The Ems met the optimal threshold of ergonomic design; however, the Eps required a better design.

CFD simulations of air curtain dust removal effect by ventilation parameters during tunneling

2020 ◽  
Vol 31 (6) ◽  
pp. 2456-2468 ◽  
Author(s):  
Shuai Yin ◽  
Wen Nie ◽  
Lidian Guo ◽  
Qiang Liu ◽  
Yun Hua ◽  
...  
Keyword(s):  
Dust Removal ◽  
Cfd Simulations ◽  
Air Curtain

An Ergonomic Testing System for the First Metatarsophalangeal Joint Stiffness

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Fatemeh Farhadi ◽  
Muhammad Faraz ◽  
Marabelle Heng ◽  
Shane Johnson
Keyword(s):  
Measurement Errors ◽  
Intraclass Correlation ◽  
Joint Stiffness ◽  
Metatarsophalangeal Joint ◽  
Testing System ◽  
Device Design ◽  
First Metatarsophalangeal Joint ◽  
Left And Right ◽  
The Mean ◽  
The Right

Osteoarthritis sufferers commonly have first metatarsophalangeal joint (MTPJ) problems in which articular surfaces are changed permanently due to fatigue. Therefore, medical devices for early diagnosis would increase the opportunity for prevention of disease progression. In previous studies on stiffness of the first MTPJ many details, although functionally of great importance, have not been fully considered including: design and size of the device, tribology consideration, and errors from device. Therefore, the motivation of our research was to enhance the device design by reducing the size of the device, and device design was enhanced by minimizing measurement errors through development of a new ergonomic left and right foot instrument located medial to the first MTPJ (instead of beneath the foot). The first MTPJ stiffness (N mm/kg radian) measurement was taken on 28 subjects with two replicates per subject by the same tester. The first MTPJ stiffness ranged from 3.49 to 14.42 N mm/kg radian with the mean (SD) value of 8.28 (3.15) N mm/kg radian for the left feet and 3.91 to 11.90 N mm/kg radian with the mean (SD) value of 7.65 (2.07) N mm/kg radian for the right feet. Reliability evaluation was measured using intraclass correlation coefficient and described an excellent reliability between two tests.

Sign in / Sign up

Export Citation Format

Share Document