Design and Study on Intrinsically Safe Circuit of Portable Infrared Methane Alarming Device

2011 ◽  
Vol 328-330 ◽  
pp. 1930-1934
Author(s):  
Xiao Hui Wang ◽  
Jing Yu Wang ◽  
Jing Lin Zhang ◽  
Ting Liang
Keyword(s):  
Infrared Absorption ◽  
Coal Mine ◽  
Detection Accuracy ◽  
Calculation Results ◽  
Gas Environment ◽  
Intrinsic Safety

Based on the theory of infrared absorption, a new kind of portable methane alarming device has been developed with the advantages that cost-low, maintenance-free, miniaturization, and integration. Intrinsically safe circuit is absolutely necessary, because the device is installed in the explosive gas environment. To improve the detection accuracy and increase the safety of the coal mine, the device’s intrinsically safe circuit has been designed. All parameters of the circuit are designed in accordance with IEC 60079-0-2007 Explosive atmospheres-Part 0: Equipment - General requirements and IEC 60079-11-2006 Explosive atmospheres-Part 11: Equipment protection by intrinsic safety “i”. The related analyses and calculation results show that this intrinsically safe circuit is workable and reliable.

scholarly journals Anomaly Detection for Time Series with Difference Rate Sample Entropy and Generative Adversarial Networks

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Keke Gao ◽  
Wenbin Feng ◽  
Xia Zhao ◽  
Chongchong Yu ◽  
Weijun Su ◽  
...  
Keyword(s):  
Time Series ◽  
Anomaly Detection ◽  
Normal Mode ◽  
Coal Mine ◽  
Spontaneous Combustion ◽  
Sample Entropy ◽  
Generative Adversarial Networks ◽  
Detection Accuracy ◽  
Gas Concentration ◽  
Adversarial Networks

The spontaneous combustion of residual coals in the mined-out area tends to cause an explosion, which is one kind of severe thermodynamic compound disaster of coal mines and leads to serious losses to people's lives and production safety. The prediction and early warning of coal mine thermodynamic disasters are mainly determined by the changes of the index gas concentration pattern in coal mine mined-out areas collected continuously. The time series anomaly pattern detection method is mainly used to reach the state change of gas concentration pattern. The change of gas concentration follows a certain rule as time changes. A great change in the gas concentration indicates the possibility of coal spontaneous combustion and other disasters. To emphasize the features of collected maker gas and overcome the low anomaly detection accuracy caused by the inadequate learning of the normal mode, this paper adopted a method of anomaly detection for time series with difference rate sample entropy and generative adversarial networks. Because the difference rate entropy feature of abnormal data was much larger than that of normal mode, this paper improved the calculation method of the abnormal score by giving different weights to the detection points to enhance the detection rate. To verify the effectiveness of the proposed method, this paper employed simulation models of the mined-out area and adopted coal samples from Dafosi Coal Mine to carry out experiments. Preliminary testing was performed using monitoring data from a coal mine. The experiment compared the entropy results of different time series with the detection results of generative adversarial networks and automatic encoders and showed that the method proposed in this paper had relatively high detection accuracy.

Multi-loop magnetisation method for detecting coal mine wire rope defects

2020 ◽  
Vol 62 (9) ◽  
pp. 540-549
Author(s):  
Wang Hongyao ◽  
Tian Jie ◽  
Meng Guoying ◽  
Zhou Junying ◽  
Hua Gang
Keyword(s):  
Permanent Magnet ◽  
Coal Mine ◽  
Detection Method ◽  
Cost Effective ◽  
Wire Rope ◽  
Degree Of Saturation ◽  
Detection Accuracy ◽  
Test Model ◽  
Wire Ropes ◽  
Shape Structure

Existing methods for detecting magnetic leakage signals from damaged wire ropes require axial saturation magnetisation and the accuracy of the detection equipment depends on the degree of saturation of the magnetisation. Moreover, owing to the special characteristics of the structure, diameter and operating environment of the wire rope, it is difficult to achieve the expected magnetisation effect. Consequently, in addition to other issues, the detection accuracy and versatility of the equipment are low. This study proposes a method based on spatial multi-dimensional orthogonal array loop magnetisation to detect coal mine wire rope defects. First, a sensor excitation structure model is developed. Then, a method for detecting the radial magnetic flux using permanent magnet arrays is analysed and the influence of the number of permanent magnet radial magnetic blocks on the magnetisation effect is studied. In addition, a wire rope detection method based on the principle of clustering is investigated and used to discuss the influence of the shape, structure and size of the sensor on the magnetisation effect. Finally, through laboratory experiments, the applicability of the test model and the proposed method are verified. The results show that the magnetisation effect is better and more cost-effective when the number of permanent magnet radial magnetic blocks is eight and that the proposed detection method can effectively identify damaged wire rope joints. Furthermore, the proposed equipment achieves a signal-tonoise ratio of 28 dB, thereby improving the reliability of damage detection.

Explosion-Proof Design for Coal Mine Rescue Robots

2011 ◽  
Vol 211-212 ◽  
pp. 1194-1198 ◽  
Author(s):  
Yun Wang Li ◽  
Shi Rong Ge ◽  
Hua Zhu
Keyword(s):  
Coal Mine ◽  
Mobile Systems ◽  
Mine Environment ◽  
Environment Exploration ◽  
Rescue Robots ◽  
Mine Rescue ◽  
Intrinsic Safety

The explosion-proof design for coal mine robots that are used to explore environment and rescue after coal mine disaster must be adopted. In order to carry out the explosion-proof design for coal mine robots reasonably, based on the analysis of coal mine robots and their explosion-proof design, the explosion-proof types for robots are studied on. The conclusions are as follows: (1) the mixed explosion-proof design including integrated and partial explosion-proof design can be adopted in the robots design; (2) protection types for robots mainly include flameproof enclosure, pressurized enclosure, intrinsic safety, and combination of them. Based on this, the explosion-proof structures of the mobile systems of a track-type robot and a rocker-type robot for coal mine environment exploration are introduced. According to the different structure of the two robots, the concentrated and dispersed flameproof enclosures are respectively designed for the track-type robot and a rocker-type robot. This paper can provide reference for the explosion-proof design for coal mine robots.

scholarly journals Mechanical Chuck Design and Slip Strength Analysis

2021 ◽  
Vol 299 ◽  
pp. 01014
Author(s):  
Zhi Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Coal Mine ◽  
Strength Analysis ◽  
Existing Problems ◽  
Initial Design ◽  
Calculation Results ◽  
Working Principle ◽  
Drilling Rigs ◽  
Element Method

Chuck is one of the key parts of coal mine tunnel drill, its performance directly affects the performance of the machine. In view of the existing problems of the hydraulic chuck, the structure of the new hydraulic chuck is designed and its working principle is briefly described. The strength of slips is analyzed by finite element method. The calculation results show that the initial design of slips meets the requirements of tunnel drilling rigs.

scholarly journals Estimate of intrinsic safety of capacitive circuits

2019 ◽  
Vol 109 ◽  
pp. 00027
Author(s):  
Oleksandr Hladkov ◽  
Anatolii Mnukhin ◽  
Rishard Stasevich
Keyword(s):  
Coal Mine ◽  
Regression Equation ◽  
Universal Method ◽  
Discharge Time ◽  
Safety Parameters ◽  
Comparison Of The Results ◽  
Contact Closure ◽  
Intrinsic Safety

A universal method has been developed and tested for computer estimate of intrinsic safety of inductive capacitive circuits, which takes into account the most hazardous discharge type by contact closure and the regression dependences are obtained of minimal igniting energy on discharge time in a capacitive circuit and the comparison is made of results with available experimental dependences. A regression equation is received which connects minimal igniting energy and discharge time as well as voltage of a capacitive circuit. The comparison of the results with available experimental dependencies is made. The intrinsic safety parameters are defined which leads to decrease of risk for explosion and freely burning fire in a coal mine.

Balanced Ventilation Principle in the Application of Shigetai Coal Mine Ventilation System Optimization

2013 ◽  
Vol 392 ◽  
pp. 95-99
Author(s):  
Wen Cai Wang ◽  
Ya Chen Li ◽  
Chao Ping He ◽  
Bo Zhang ◽  
Hui Zhao
Keyword(s):  
Coal Mine ◽  
Ventilation System ◽  
System Optimization ◽  
Mine Ventilation ◽  
Line Length ◽  
Simulation Calculation ◽  
Resistance Measure ◽  
Calculation Results

In order to reduce Shigetai coal mine ventilation resistance of mine ventilation system, using balanced ventilation principle Shigetai coal mine ventilation resistance of mine ventilation system was analysed and balanced, and the balanced ventilation resistance measure mine ventilation resistance in 2014-2015 simulation calculation. Results suggest that balanced ventilation measures implemented in mine ventilation resistance, coal mine ventilation resistance in the next two years not only with increased ventilation line length increases, but lower. Visible, balanced ventilation of mine has better technical and economic results are obvious, merits promotion.

scholarly journals Simulation Research on Application of Azimuth Electromagnetic Wave in Coal Seam Detection

2020 ◽  
Vol 165 ◽  
pp. 03032
Author(s):  
Chen Gang ◽  
Chen Long ◽  
Fan Yiren ◽  
Li Quanxin
Keyword(s):  
Electromagnetic Wave ◽  
Coal Seam ◽  
Coal Mine ◽  
Optimization Design ◽  
Working Environment ◽  
Detection Accuracy ◽  
Simulation Research ◽  
Low Efficiency ◽  
Parameter Optimization Design ◽  
Research On Application

Aiming at the problems of poor detection accuracy and low efficiency on the roof and floor interface in horizontal well drilling in coal mine, the design idea of explosion-proof azimuth-while-drilling electromagnetic wave logging instrument in coal mine was put forward. In order to suit the working environment of underground coal seam, the change law of the influence of instrument parameters such as source distance and coil installation angle on the signal response was obtained through forward simulation. Through the simulation research on the response of azimuth-while-drilling electromagnetic wave logging instrument, it provided a basis for selection of parameter optimization design of the instruments applicable to the underground coal mine, and the change law of the response of coal rock roof and floor interface was mastered. The application of this instrument will improve the detection accuracy and efficiency on the roof and floor.

scholarly journals Designing Optically & Utilization of Thermopile Chip with Resonant Cavity Absorber Structure as IR Absorber

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 302
Author(s):  
Haigang Hou ◽  
Jian Yang ◽  
Guiwu Liu ◽  
Junlin Liu ◽  
Mudassar Abbas ◽  
...  
Keyword(s):  
Infrared Absorption ◽  
Duty Cycle ◽  
Dielectric Layer ◽  
Metal Layer ◽  
Optical Design ◽  
Resonant Cavity ◽  
Cavity Structure ◽  
Calculation Results ◽  
Absorber Structure ◽  
Suspension Structure

This paper presents a novel thermopile chip in which the resonant cavity structure was fully utilized as an absorber by an optical design. The resonant cavity absorber structure was designed using Al as anthe bottom reflective metal layer, air as the intermediate dielectric layer, and SiO2/TiN/Si3N4 sandwich layers as the top absorption layer, while the bottom reflective metal (Al) was deposited on the cold junctions of the thermopile. The simulation and calculation results show that the thermopile chip with resonant cavity absorber structure not only has great infrared absorption in the wide infrared absorption range but also can effectively prevent the cold junctions from absorbing infrared radiation and inhibit the rise of temperature. As a result, the temperature difference between the hot junctions and the cold junctions is increased, and the responsivity of the thermopile chip is further improved. Moreover, the duty cycle of the thermopile chip is greatly improved due to the double-layer suspension structure. Compared with the traditional thermopile chip structure, the sizes of the thermopile chip with the resonant cavity absorber structure can be further reduced while maintaining responsivity and specific detectivity.

Sign in / Sign up

Export Citation Format

Share Document