Modern crushing machinery was created after the gradual improvement and popularization of power machinery such as steam engines and electric motors.
In 1806, a roller crusher driven by a steam engine appeared;
In 1858, Blake in the United States invented the jaw crusher to break rocks;
In 1878, the United States developed a gyratory crusher with continuous crushing action, and its production efficiency was higher than that of jaw crusher with intermittent crushing action;
In 1895, William of the United States invented an impact crusher with low energy consumption.
In the 80s of the 20th century, the feed size of the large jaw crusher, which crushes 800 tons of materials per hour, has reached about 1800 mm.
There are two types of jaw crushers commonly used: double toggle plate and single toggle plate. The former only makes a simple arc swing when working, so it is also called a simple swinging jaw crusher; The latter moves up and down while swinging in an arc.
The technical level of domestic jaw crusher manufacturers is very different, and the products of a few manufacturers are basically close to the world's advanced level, while the products of most manufacturers are far behind the world's advanced level. The jaw crusher frame accounts for a large proportion of the mass of the whole machine (50% for the cast frame and 30% for the welded frame). Foreign jaw crushers are all welded frames, and even the moving jaws are welded structures. The use of welded frame for jaw crusher is the development direction. There are many examples of unreasonable structural design of domestic jaw crusher, and the reason is that the stiffeners are not arranged according to the actual force of the crusher
In recent years, with the increase in the proportion of open-pit mining, as well as the adoption of large electric shovels (excavators) and large mining vehicles, the ore block degree transported from open-pit mines to the crushing workshop has reached 1.5~2.0 meters; At the same time, due to the decreasing grade of raw ore, in order to maintain the original production capacity of the concentrator, it is necessary to greatly increase the mining and crushing of raw ore, so the jaw crusher is developing in the direction of large-scale. At present, the largest jaw crusher manufactured abroad is: 3000×2100 mm (simple pendulum), 1800 mm of ore feeding, and 1100 tons/unit·h of production capacity; 2100×1670 mm (compound pendulum), when the discharge port is 355 mm, its production capacity is 3000 tons/unit·h.
With the emergence of impact-resistant large-scale rolling bearings, there is a trend of using compound pendulum jaw crusher instead of simple pendulum crusher at home and abroad, because under the same conditions, the former has 30% higher production capacity than the latter; When the production capacity of the two is the same, the former is 20%~30% lighter than the latter. However, there are still some problems in the structure of the compound pendulum jaw crusher, which need to be studied and improved.
It should be noted that in recent years, due to the improvement of China's large-scale rolling bearing materials and the need for underground coarse crushing equipment, the compound pendulum jaw crusher also has a trend of developing in the direction of large-scale, and is currently trial-producing 900×1200 compound pendulum crusher. With the large-scale equipment specifications, the adjustment device and safety device of the general jaw crusher must adopt a new mechanism. Therefore, another trend in the development of the current jaw crusher is that the size of the discharge port adopts a hydraulic adjustment mechanism, which is not only simple and fast, but can be adjusted as needed at any time in the work; At the same time, the safety device of the overload of the machine is also a hydraulic mechanism to achieve safety and reliability, and the thrust plate is not damaged, and the machine resumes work immediately after troubleshooting. This hydraulic jaw crusher is being vigorously developed at home and abroad. China has produced 900×1200 hydraulic pendulum jaw crushers, and put into production and use in Laiwu iron ore and roots iron ore. Production practice has proved that the insurance mechanism and adjustment mechanism of the hydraulic jaw crusher have achieved the purpose of safety insurance and convenient adjustment, and the situation is good, and it is well received by the post workers.
In terms of improving the crushing efficiency of the jaw crusher, in addition to making local improvements in the structure of the original equipment, such as increasing the height of the crushing chamber and increasing the production capacity; Reduce the discharge port and increase the crushing ratio; In addition to increasing the swing speed of the moving jaw to improve the production capacity of the equipment and improve the product quality, at present, all countries are studying and testing new types of crushers, such as impact jaw crushers, double-acting jaw crushers and hydraulic transmission jaw crushers.
