The development of in-line oil contamination sensor for N320 Lubricant used in scraper conveyor reducer is described. The sensor can detect the NAS contamination level of the lubricant and prompt the replacement of oil when the oil contamination level exceeds the indicator of the exchanging standard of L-CKC industrial closed gear oil. This paper describes the sensor's design requirements, principle of operation, selection of wavelength, mechanical structure design and test calibration. The shortcomings of the sensor and relevant solutions are also pointed out in this article.

The central groove is a key component of armored face conveyor. Failure of welded joints in the central groove often occurs in engineering. In this article, the welding procedure parameters were analyzed to the improve strength and toughness of the dissimilar steel weld joint in the central groove. First, four types of super-high wear-resistant steel and two types of high-strength welding wire were chosen as the welding materials. Carbon equivalent method, cold crack sensitivity index method, and maximum hardness of heat-affected zone test were applied to analyze their welding properties. Second, to improve their weldability, the proper preheating temperature was determined using Y-groove cracking test and mechanical property tests. Finally, a semi-automatic CO 2 welding method was adopted, and a second mechanical property test was conducted to determine the proper welding wire. Results show that the chosen steels have poor weldability and cold cracking sensitivity. Preheating must be used to prevent cold cracking. When the preheating temperature is higher than 80°C, the cold crack rate can be controlled to under 20%, which can satisfy application requirements. Welding wire YMGR76 is appropriate. Using YMGR76, the preheating temperature drops to 120°C, and the strength and toughness of the weld joint are improved to 813 MPa and 112 KV 2 /J, respectively. This study provides a welding procedure to improve the reliability of the central groove.

In this paper, according to the problem of multiload on centerlized belt conveyor during mine production process, an autocontrol system based on armoured belt feeder and PLC, is studied to ensure conterlized belt conveyor running steadily and safely. This system realizes a clock loop control via the feedback signal of driving motor current which reflect the change of coal quantity, and can automatically adjust the real-time transport capacity of each armouted belt feeder to optimize the overall quantity of coal on centerlized belt conveyor.Keywords-armoured belt feeder; multi-loading; coal quantity I.

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