What is the difference between hammer and impact crusher?

Hammer crushers operate based on the high - speed impact of hammers. A motor drives a rotor at high speed, and hammers attached to the rotor rotate along with it. When materials enter the crushing chamber, they are immediately struck by these high - speed hammers. The impact force not only breaks the materials but also imparts kinetic energy to them. The broken materials then collide with the inner walls of the crusher and each other, further reducing their size. Eventually, materials that are smaller than the gaps in the grate bars at the bottom of the crusher are discharged as the final product. For example, in a coal - processing plant, a hammer crusher can quickly break down large chunks of coal into smaller pieces suitable for further processing.

Impact crushers also rely on high - speed impact, but with a slightly different mechanism. In an impact crusher, materials are fed into a high - speed rotating rotor. The rotor has blow bars or hammers that strike the incoming materials. 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 the fragmentation of the materials. Vertical shaft impact crushers (VSIs), a type of impact crusher, 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.

Hammer crushers typically have a relatively simple structure. They mainly consist of a frame, a rotor, hammers, and grate bars. The frame provides the support for the entire crusher. The rotor, which is key to the operation, is equipped with multiple hammers. These hammers are usually made of wear - resistant materials such as manganese steel. The grate bars at the bottom of the crusher play a crucial role in controlling the size of the final product by allowing only materials of the appropriate size to pass through.

Impact crushers, especially horizontal shaft impact crushers (HSIs), have a more complex structure in some aspects. They have a rotor, blow bars, impact plates, and a crushing chamber. The impact plates are adjustable, which allows 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 often more focused on optimizing the impact forces and material flow within the crushing chamber.

Hammer crushers are best suited for materials with medium to low hardness and brittleness. Materials like limestone, coal, gypsum, and shale can be effectively processed by hammer crushers. For instance, in a limestone quarry, a hammer crusher can be used to break down the limestone into aggregates for construction purposes. However, when dealing with very hard and abrasive materials, the hammers in a hammer crusher tend to wear out quickly, which reduces its efficiency and increases maintenance costs.

Impact crushers can handle a wider range of materials. They are effective for both medium - hardness materials and some relatively hard materials. In the mining industry, impact crushers are used to crush ores such as copper ore and iron ore. They can also process materials like granite and basalt, which are relatively hard. The ability of impact crushers to handle different materials is due to their more robust design and the adjustable components that can be optimized for specific materials.

The product granularity of a hammer crusher is relatively coarser when compared to some impact crushers. The size of the final product is mainly determined by the gaps in the grate bars. While it can produce a range of particle sizes, achieving a very fine and uniformly - sized product can be challenging. In applications where a rough - sized product is acceptable, such as in some basic construction aggregate production, a hammer crusher can be a suitable choice.

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.

In a hammer crusher, the hammers are the main wear - prone parts. Since they are constantly in contact with the materials being crushed, they need to be replaced relatively frequently, especially when processing hard materials. Additionally, the grate bars may also experience wear and may need adjustment or replacement over time. The maintenance process for a hammer crusher often involves checking and replacing the hammers and maintaining the grate bars.

For impact crushers, the blow bars and impact plates are the main components that experience wear. However, the wear rate can vary depending on the type of material being processed and the design of the crusher. 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, but generally, proper maintenance of the key components is essential to ensure optimal performance.

BBjump's View: As a sourcing agent, when clients are deciding between a hammer crusher and an impact crusher, they should first assess their material - processing requirements in detail. If the materials are mainly of medium - low hardness and a coarser product granularity is acceptable, a hammer crusher can be a cost - effective choice due to its simple structure and relatively low initial cost. However, if the materials vary in hardness, or if a high - quality, uniformly - sized product is needed, an impact crusher is likely to be more suitable. When choosing a manufacturer, clients should look for one with a good reputation for producing durable and reliable crushers. They should also consider the availability of spare parts and after - sales service. A manufacturer that can provide quick replacement of wear - prone parts and offer technical support for maintenance can significantly reduce the downtime of the equipment and increase its overall productivity.

Hammer crushers are not ideal for crushing hard materials such as granite. The hammers in a hammer crusher will wear out very quickly when processing hard and abrasive materials like granite. This will lead to frequent replacement of hammers, high maintenance costs, and reduced efficiency. It is recommended to use an impact crusher or other crushers specifically designed for hard materials for granite crushing.

Impact crushers, especially vertical shaft impact crushers (VSIs), are more suitable for producing fine - sized and uniformly - shaped products. The impact and shaping mechanisms in impact crushers can break materials in a way that results in a more controlled and finer particle size distribution. Hammer crushers typically produce a coarser product, and achieving a very fine product with a hammer crusher can be difficult.

In a hammer crusher, the hammers and grate bars are the main components that require frequent maintenance. Hammers need to be replaced regularly due to wear from striking the materials. The grate bars may also need adjustment or replacement. For impact crushers, the blow bars and impact plates are the key wear - prone parts. The maintenance process for impact crushers may involve repositioning or replacing the impact plates and checking the condition of the blow bars. The wear rate and maintenance frequency can vary depending on the type of material being processed in both crushers.