The hammer crusher is a type of ore crushing equipment. It can be used to crush medium-hard brittle materials with low water content, such as limestone, gypsum, slag, coke, coal, etc. It is widely used in cement manufacturing, chemical, electric power, metallurgy, and other industries.
Hammer crusher mainly breaks materials by the impact of hammers. The material entered into the working area of the crusher is crushed by high-speed hammers. The crushed material obtains kinetic energy from the hammers, and then it impacts on the crushing plate and grate screen at high speed and is broken for the second time. After that, the material smaller than the gap of the grate screen is discharged, and the material with larger particle size is bounced back to the lining plate and crushed by the additional impact of the hammers. The materials also impact each other during the whole crushing process in the crusher.
We take a 900 x 900mm single rotor, irreversible multi-row hinged hammer crusher as an example to introduce its structure and parts. This type of hammer crusher is commonly seen in cement plants and is suitable for crushing limestone, coal, and other medium hardness ores. It is mainly composed of a transmission device, rotor, lining plate, grate screen, and shell.
The shell is composed of the lower body, the upper rear cover, the left and the right side walls. Each part is connected by bolts. A feeding port is set on the upper part. The inner part of the shell is made of manganese steel, which can be replaced after being worn. The lower body is welded by steel plates in order to place the bearing to support the rotor on both sides of the lower body. A shaft seal device is arranged between the casing and the shaft to prevent ash leakage.
The rotor is composed of main shaft, hammer holder, and pin shaft. The hammer is suspended on the hammer holder in eight rows by the pin shaft. In order to prevent the axial movement of the hammer frame and the hammer head, both ends of the hammer frame are fixed with a compression disc and a lock nut. In addition, in order to make the rotor store a certain amount of kinetic energy in motion, flywheel or large pulley should be installed at one end of the main shaft.
The main shaft is the main part supporting the rotor, which needs to bear the mass and impact force from the rotor and hammer head in the process of operation, so its material must have high strength and toughness.
The hammer holder is used to hang the hammer heads. Although it does not directly participate in the process of crushing materials, it is still subject to the impact and friction of ore and wear, so it should be made of materials with good wear resistance.
The heavier the hammer, the more kinetic energy it possesses, and the higher the crushing efficiency. But heavy hammer also causes more damage to other parts and accelerate their wear process. The hammer weight should be able to balance the production efficiency and the wear rate.
The arrangement of grate bars of the hammer crusher is a circular arc that is perpendicular to the moving direction of hammerhead and has certain clearance with the rotary radius of rotor. The material smaller than the gap between grate bars can pass through the gap, and the material larger than the gap will be continuously impacted, ground and broken by the hammers until it can pass through the gap. Due to the impact of hard materials and metal blocks, the grate is easy to bend and break, so it needs to be inspected and replaced frequently.
The lining plate is installed inside the shell to protect it from the ore. The lining plate is cast by high manganese steel, the same material used for grate bar and hammer. The lining plate can be replaced when it is seriously worn to ensure product quality.
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