In the past, small and medium-sized sand and gravel quarries often use fine jaw crusher as secondary crushing equipment, and at present, large and medium-sized sand and gravel quarries are dominated by cone crusher. In some special occasions, such as the requirements of the ore product granularity cubic shape is particularly strict (i.e., less needle flake particles), often use the impact crusher as a secondary or tertiary crushing equipment (impact broken grain better), such as China's high-grade highway construction of pavement quarry commonly used in this type of equipment. In foreign countries, due to the urban construction waste of reinforced concrete regeneration is very popular, therefore, the use of impact crusher as the main equipment is very common.
Impact crusher with the rotor diameter and effective length as the specification of the division standard, the gap between the typical products at home and abroad is mainly product design and wear-resistant materials.
1、Product design
The same specification of the impact crusher at home and abroad is similar to the quality of the host, however, foreign products shell quality is small, rotor and impact frame quality. However, the quality of foreign products is small, and the quality of rotor and impact frame is large, while the quality of domestic products is large, and the quality of impact frame is small. Due to the small mass of the rotor, the rotational inertia is small, and the power of the dragging motor is also small, especially in the crushing of hard rock and hope to get small particles when the processing capacity is low.
In addition, in the design of the impact cavity, the adjustment of the impact plate for different particle size requirements, and the replacement of the plate hammer, etc., the difference in design between domestic and foreign products is also very obvious. These aspects of the bad design, not only affect the quality of the product, but also to the use, maintenance also brings a lot of inconvenience.
2、Wear-resistant materials
As a secondary or tertiary crushing impact crusher, in the crushing of hard materials, its main wear-resistant parts of the plate hammer made of high-chromium cast iron, China's high-chromium cast iron standards (wear-resistant white cast iron standards) applies to small parts. For large parts, such as hundreds of kilograms of plate hammer quality control standards are not complete, the host manufacturer does not manufacture wear-resistant materials, so the quality of wear-resistant parts such as plate hammer easy to lose control. What's more, many casting manufacturers lack the necessary quality control conditions, therefore, under the same working conditions, the service life of wear parts at home and abroad is often 1 times the difference.
The development history of impact crusher can be traced back to the 1850s, because of its relatively high production efficiency, can handle a variety of materials, the structure of the form is relatively simple, easy to move, and so on, and thus the rapid development. 1952, China appeared in the first real impact crusher, after many years of development, the level of impact crusher manufacturing is gradually maturing, but in order to eliminate the gap between the level of the international level, the equipment manufacturer should also insist on technological innovation, improve the degree of automation, and gradually get rid of the single introduction and imitation of products.