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As the core parts of impact crusher, once the rotor is broken, it means that the production is suspended, and the loss caused by shutdown is not expected to be seen. In this case, are there any emergency solutions to solve the urgent problem?
A sand and aggregate company applies impact crusher as the second crushing equipment. The impact crusher has been running normally for 4 years. After routine shutdown inspection, it was found that there was a crack in the rotor of the impact crusher. Emergency measures were taken to deal with the problem, so that the production could proceed smoothly.
The rotor of the impact crusher is welded structure of steel plate, and made of ZG20SiMn. The rotor rib plate is cracked through, and there are symmetrical cracks on both sides of the rib plate. According to the analysis, the causes of rotor fracture are as follows:
(1) The thickness of the broken rib plate is 150 mm, and there are manufacturing defects inside the rib plate;
(2) The stress concentration exists at one end of the crack;
(3) Each plate hammer is fixed by the inclined fastening plates under the three rib plates. The three fastening plates may have inconsistent bolt tightening force, which may lead to the inconsistent stress of rib plates, and the excessive stress of one fastening plate will cause the rib plate fracture.
Due to the lack of rotor spare parts and the scheduled maintenance time is not reached, plus the heavy production task, only emergency measures can be taken.
(1) On both sides of the crack, a groove of 50 mm wide and 50 mm deep shall be gouged with carbon arc, and the groove shall be polished with a polishing machine;
(2) The cracks are welded with ER50-6 welding wire;
(3) The same reinforcing plate is welded on both sides of the broken rib plate and the rib plate at the symmetrical position. The reinforcing plate is made of Q345B, and the reinforcing plate is welded with ER50-6 welding wire. The problem of rotor balance of impact crusher is considered during welding. After crack treatment, the vibration of the impact crusher is in normal range, and it is put into operation without balancing.
After the solution taken for rotor failure of impact crusher, it has been used for nearly half a year, and the impact crusher is in normal operation and the output is not affected. Considering the reliability of the equipment operation and combining with the actual production situation, it is considered to replace the rotor during overhaul.