What is the difference between impact crusher and jaw crusher?

Impact crushers operate based on the principle of high - speed impact. A high - speed rotating rotor is equipped with blow bars or hammers. When materials enter the crushing chamber, they are immediately struck by these high - speed components. The impact force not only breaks the materials but also imparts kinetic energy to them. After being hit, the materials are thrown against impact plates or aprons. The repeated impact between the materials, the blow bars, and the impact plates leads to further fragmentation. For example, in a horizontal shaft impact crusher (HSI), the rotor rotates horizontally, and the materials are fed into the crusher and then hit by the hammers on the rotor, followed by collisions with the impact plates. Vertical shaft impact crushers (VSIs) accelerate materials in the center of the rotor and eject them outwards to collide with an anvil or in a rock - on - rock crushing mechanism, which is particularly effective in shaping materials.

Jaw crushers work on the principle of compression. They have a fixed jaw and a moving jaw. The material is fed into the V - shaped crushing chamber formed by these two jaws. As the moving jaw moves towards the fixed jaw in a reciprocating motion, the materials are gradually compressed and crushed. The movement of the moving jaw is usually driven by an eccentric shaft, which causes the jaw to move in an elliptical path. When the moving jaw moves away from the fixed jaw, the crushed materials are discharged from the bottom of the crusher. For instance, in a primary jaw crusher used in a quarry, large boulders are fed into the crusher and are gradually broken down into smaller pieces as the jaws close in on them.

Impact crushers, especially HSIs, have a structure that includes a rotor, blow bars, impact plates, and a crushing chamber. The rotor is a crucial part, often made of high - strength materials to withstand high - speed rotation and impact forces. The blow bars, which strike the materials, are also made of wear - resistant materials such as manganese steel or high - chromium cast iron. The impact plates are adjustable, allowing for more precise control over the product size. In VSIs, the unique vertical - shaft design and the rock - on - rock or rock - on - anvil crushing mechanisms add to their structural distinctiveness. The overall design of impact crushers is focused on optimizing the impact forces and material flow within the crushing chamber.

Jaw crushers mainly consist of a frame, a fixed jaw, a moving jaw, an eccentric shaft, a toggle plate, and a flywheel. The frame provides the support for the entire crusher and needs to be sturdy enough to withstand the large forces generated during the crushing process. The fixed jaw is stationary, while the moving jaw is connected to the eccentric shaft through the toggle plate. The flywheel helps to maintain the momentum of the moving jaw and ensures a smooth operation. The structure of jaw crushers is relatively simple in comparison to some impact crushers, but it is designed to be robust for handling large and hard materials.

Impact crushers can handle a wide range of materials. They are effective for both medium - hardness materials and some relatively hard materials. In the mining industry, they are used to crush ores such as copper ore, iron ore, and gold ore. They can also process materials like granite, basalt, and limestone. Their ability to handle different materials is due to their more robust design and the adjustable components that can be optimized for specific materials. However, when dealing with very sticky or wet materials, impact crushers may face some challenges as the materials can adhere to the components and affect the crushing efficiency.

Jaw crushers are particularly suitable for crushing large and hard materials. They are often used as primary crushers in mining and quarrying operations. Materials such as large boulders, hard rocks, and ores with high compressive strength can be effectively processed by jaw crushers. They can handle materials that are difficult to break with other crushers. For example, in a granite quarry, jaw crushers are used to initially break down the large granite blocks into smaller, more manageable pieces for further processing. Jaw crushers are also less affected by the moisture content of the materials compared to some other crushers, making them suitable for processing materials with a certain level of wetness.

Impact crushers, especially VSIs, are known for their ability to produce a more cubical - shaped and uniformly - sized product. The impact and shaping mechanisms in impact crushers can break materials in a way that results in a more desirable particle shape. This is highly beneficial in applications like high - strength concrete production, where well - shaped aggregates can improve the workability and strength of the concrete. Impact crushers can produce a relatively wide range of particle sizes, and by adjusting the impact plates and other components, the product granularity can be fine - tuned to meet specific requirements.

Jaw crushers typically produce a product with a more irregular shape compared to impact crushers. The size of the final product is mainly determined by the gap between the jaws at the discharge end. While they can reduce large - sized materials to a certain extent, achieving a very fine and uniformly - sized product is more challenging with jaw crushers. The product of jaw crushers is often suitable for applications where a coarser - sized product is acceptable, such as in the initial stages of aggregate production or for some basic construction projects.

For impact crushers, the blow bars and impact plates are the main components that experience wear. The wear rate depends on the type of material being processed and the operating conditions. In some cases, the adjustable impact plates in HSIs can be repositioned or replaced, which can extend the overall lifespan of the wear - prone parts. VSIs, with their unique crushing mechanisms, may have different wear patterns. Regular maintenance, including checking the wear of components, proper lubrication, and timely replacement of worn - out parts, is essential to ensure optimal performance. However, due to the high - speed impact operation, impact crushers may require more frequent maintenance in some situations.

In a jaw crusher, the jaws (both the fixed and moving jaws) are the main wear - prone parts. Since they are constantly in contact with the materials being crushed, they need to be made of wear - resistant materials. The toggle plate and the eccentric shaft may also experience wear over time. The maintenance process for a jaw crusher often involves checking and replacing the jaws, as well as maintaining the proper alignment and operation of the eccentric shaft and toggle plate. Compared to impact crushers, jaw crushers generally have a simpler maintenance process in terms of component replacement, but they still require regular inspection to ensure smooth operation.

BBjump's View: As a sourcing agent, when clients are choosing between an impact crusher and a jaw crusher, they should first clearly define their material - processing requirements. If the materials are large and hard, and a coarser product is acceptable in the initial stages of processing, a jaw crusher is a great choice. Its simple structure and ability to handle tough materials make it reliable for primary crushing. However, if the goal is to produce a high - quality, uniformly - sized and well - shaped product, especially for applications like high - end construction materials, an impact crusher, especially a VSI, is more suitable. When selecting a manufacturer, clients should look for a company with a good reputation for quality and durability. They should also consider the availability of spare parts and after - sales service. A manufacturer that can provide quick replacement of worn - out parts and offer professional technical support can significantly reduce the downtime of the equipment and increase its overall productivity.

Yes, impact crushers can be used as primary crushers in some cases, especially when dealing with materials that are not extremely large and hard. However, jaw crushers are more commonly used as primary crushers because they are better suited for handling large - sized and very hard materials. Impact crushers may be more suitable for primary crushing when the material is of medium hardness and there is a need for a certain degree of product shaping right from the start.

The energy efficiency of the two crushers depends on various factors such as the type of material being processed, the desired product size, and the specific model of the crusher. Generally, for crushing hard and large - sized materials in large quantities, jaw crushers can be energy - efficient in the primary crushing stage as they use a simple compression mechanism. Impact crushers, especially when used for producing well - shaped products, may consume more energy due to the high - speed impact operation. But in some cases where the material is easier to break and a high - reduction ratio is required, impact crushers can be more energy - efficient.

The operating costs of impact crushers are often higher in terms of maintenance and component replacement. The high - speed impact operation causes more wear and tear on components like blow bars and impact plates, which need to be replaced more frequently. Jaw crushers, on the other hand, have relatively lower maintenance costs for components like jaws, although they still need regular inspection and replacement. However, if considering energy consumption, as mentioned earlier, it varies depending on the application. In summary, for long - term operation, the operating cost of an impact crusher may be higher than that of a jaw crusher in many cases, but it also depends on the specific processing requirements.