| Along with the fast development of economy in our country, requirement to energy source are increasing day by day. It will not change that the coal is main energy source in our country in a long period. The number of coal mines in our country is large, and the measurement techniques are uneven. These facts lead to the appearance of colliery accidents. The main reasons are the accidents of roof and gas. The harm of roof accidents is tremendous to coal mine. According to the count of colliery accidents, the number of roof accidents stand at top of every accident.Observing the pressure of coal mines is one of the most important jobs to realize scientific management in coal mines and to reduce the number of roof accidents. At present, most instruments and meters in the coal mines in our country are simple and with low precision, such as mechanical type roof pressure sensor, hydraulic roof pressure sensor, etc. in recent years, through the continuous efforts of researchers, resistance strain gauge type roof pressure sensor and vibrating wire type roof pressure sensors has been developed and been widely used in coal mines. However, some shortcomings such as low success rate when be installed, unreliable, are difficult to debug and so on exist in use of these roof pressure sensors. Therefore, it is extremely urgent to design a new type of sensor with high reliability, easy installation and debugging.Based on deep understanding of domestic and international coal mine roof pressure sensor, after careful analysis the shortages of current underground pressure sensors, and to consider the specific environmental of coal mines, a new type of volumetric roof pressure sensor has been designed in the paper. The sensor consists of three central components, namely:interface for pressure conversion, pipelines for pressure transmission and components for pressure sensing. In this paper, that the material, structure and various parameters of the components for pressure sensing have been studied theoretically, the structure of the components for pressure sensing have been analyzed through computer simulation (finite element method), and then its specific structure has been determined. This new type of pressure sensing has been declared a national patent of utility model (in the process of declaring to wait for the final result). In this paper, the overall design of volumetric pressure sensor has been expounded simply, a clear overall structure has been determined, and the part of pressure sensing has been analyzed in detail. After a number of analyses through finite element method and studies in theory, the actual structures and the specific sizes of the part of pressure sensing have been determined. Compared with traditional resistance strain gauge type roof pressure sensor and vibrating wire type roof pressure sensors, this sensor has the characteristics such as reliable operation, simple installation, convenient debugging, etc. Therefore, this sensor can enhance the reliability of coal mine roof pressure testing, and then will be convenient for realizing automatic detection and scientific management. It has important practical significance to improve the efficiency of coal production in our country and safety in coal mine. |
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