Mineral sizers is a new type of crushing equipment in recent years, which is widely used in open pit and underground mines at home and abroad. In recent years, the domestic Zhunge coal mine, Pingshuo Antaibao coal mine, Datong coal mine, Xinjiang coal mine, Taiyuan coal mine, Jiaozuo River coal mine and other coal mine have imported more than 50 sets of mineral sizer . However, due to the high price of introduction, it has become an urgent task to digest and absorb the technology. The crushing roller tooth is the most critical part of the double-toothed roller breaking machine, and its structure is reasonable or not, not only directly affects the service life of the whole equipment, but also the crushing power consumption. The production capacity and the quality of the particle size are closely related ", so in the design process of double toothed roller crusher, the shape selection and design method of crushing roller teeth is a key technology. Domestic some heavy machinery manufacturing enterprises have been able to produce with independent intellectual property rights of small and medium-sized double toothed roll crusher, but the key technology of crushing roller tooth has failed to fully support grip, field operation using various defects exist in the process, the serious influence the whole performance of the double toothed roll crusher, based on the large double toothed roll crusher for 1250 as the research object, Through the operation of double tooth roller crusher analysis,. Find out the cause of tooth damage of crushing roller. The effective improvement measures are put forward to provide a theoretical basis for the design of the roller teeth of mineral sizer.
1. Operation and use status of Xinjiang coal mine 1250 large mineral sizers
Xinjiang coal mine open-pit mine uses Citic heavy machinery production of 1250 large double tooth roller crusher. It is used for crushing stripping, and its main parameters are shown in Table 1. The crusher's production capacity can meet the requirements of users, but the inspection volume is large, the main reason is that the teeth of crushing roller must be maintained every time the stop. In the operation site, it can be clearly seen that most of the wear-resistant coating on the surface of the crushing roller teeth has fallen off, and the wear is very heavy, and the crushing roller teeth have been broken, as shown in FIG. 1 The use of Xinjiang coal mine 1250 large mineral sizer and FIG. 2 The damage of the crushing roller teeth.

The mineral sizers can be seen from the operation of Xinjiang coal mine 1250 large mineral sizer that most of the wear-resistant coating on the surface of the crushing roller teeth are almost off, and the wear is very serious.
The reasons are analyzed. One is that when a large chunk of crushing material falls from the heavy plate feeder to the crusher, the wear-resistant coating on the surface of the crushing roller teeth is dropped, which aggravates the wear of the crushing roller teeth. Second, due to the poor welding performance of crushing roller teeth, the quality of wear-resistant coating is not good, and the coating is easy to fall off. Third, the choice of electrode is not correct.
As can be seen from mineral sizers tooth damage of crushing roller. The teeth of the crushing roller are broken, and there is material on the joint surface between the teeth of the crushing roller and the teeth seat. The reasons are analyzed. First, the shape design of crushing roller teeth is not reasonable, which leads to the bad state of force, and it is easy to break when it is affected by large impact or hard to break materials. Second, there are defects in the manufacture of crushing roller teeth, which lead to the joints between crushing roller teeth and tooth seat can not be accurately engaged, and the force state of crushing roller teeth is not good.
Through the above analysis, it can be seen that the main reasons for the damage of the crushing roller teeth of mineral sizer are the large impact force when the material falls, the problem of wear-resistant coating, and the problem of the design and manufacture of the crushing roller teeth.
Wear resistant coating of roller teeth of double tooth roller crusher falls off. Serious wear problems, can use the following three measures. The first is to control the falling height of the material to avoid the wear-resistant coating of the crushing roller teeth damaged by large materials: the second is to use alloy steel with good welding performance to cast the matrix and hardmetal welding wire to surfacing to ensure the quality of the wear-resistant coating; the third is to use wear-resistant steel to cast the crushing roller teeth as a whole. High strength, good wear resistance. But the casting quality requirements are higher.
The following three measures can be taken to solve the problem that the mineral sizers teeth of crushing roller are broken and the joint surface between the teeth of crushing roller and the teeth seat is stuck with materials. Firstly, the tooth shape of crushing roller teeth should be optimized to improve the stress state and improve the service life of crushing roller teeth. Secondly, the tolerance and process of the joint surface of crushing roller teeth should be reasonable. Thirdly, the teeth of crushing roller should be detected to minimize casting defects.
(1) of the double toothed roll crusher the actual usage, it is concluded that broken roller teeth three main form of damage, {2) through the analysis of the crushing roller tooth damage form, get the damage reason, one is the material of the falling impact: the second is the problem of wear resistant coating: three is broken roller gear tooth profile design and manufacturing problems.
(3) In view of the reasons for the damage of mineral sizers crushing roller teeth, the effective improvement measures are put forward.

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