Crusher and its type Crusher type Crushers are divided […]
Crusher and its type
Crushers are divided into three categories according to their crushing stage. They are (i) primary crusher, (ii) secondary crusher and (iii) tertiary crusher. The primary crusher receives materials directly from the mine (ROM) after sandblasting and reduces the size for the first time. The output of the main crusher is sent to the auxiliary crusher, which further reduces the size of the material. Similarly, the output of the secondary crusher is fed to the tertiary crusher, which further reduces the material size. Before reducing to the required size, some materials may go through four or more crushing stages. As a means of tightly controlling product size and limiting waste, the degree of crushing is distributed in multiple stages.
Crushers are also classified by mechanically transferring crushing energy to the material. Jaw, rotary and roller crushers work by applying pressure, while impact crushers such as hammer crushers achieve crushing by applying high-speed impact forces.
There are many types of crushers used in various industries. These are given below.
Jaw crusher is used as primary crusher. It uses compressive force to destroy the material. The mechanical pressure is obtained through the two jaw plates of the crusher. The reduction ratio is usually 6: 1. The jaw crusher consists of two vertical jaws installed in a V shape, the top of the jaw is farther than the bottom.
One jaw remains stationary and is called a fixed jaw, while the other jaw is called a swing jaw and moves back and forth relative to this jaw through a cam or link mechanism. The volume or cavity between the two jaws is called the crushing cavity. The movement of the swinging claw may be very small, because it will not be completely squeezed in one stroke. The inertia required to crush the material is provided by a counterweight flywheel that can move the shaft, causing an eccentric motion, which causes the gap to close.
The feed enters the crusher from the top, and the blocks between the blocks are broken. Jaw crushers are heavy machines, so they need to be durable. The outer frame is usually made of cast iron or steel. The jaws themselves are usually made of cast steel. They are equipped with replaceable lining made of manganese steel or Ni-hard (Ni-Cr alloy cast iron). Usually both jaws are covered with a replaceable lining. Also in some types, the bushing can be turned upside down after a period of time, thereby extending the replacement time.
The basic concept of a gyratory crusher is similar to a jaw crusher. It consists of a concave surface and a conical head. Both surfaces are usually lined with manganese steel. The inner cone has a slight circular motion, but does not rotate. This movement is generated by the eccentric device. The crushing effect is caused by the narrow gap between the bushing line (movable) installed on the central vertical main shaft and the recessed bushing (fixed) installed on the main frame of the crusher. The gap is opened and closed by an eccentric wheel at the bottom of the main shaft, which causes the center to rotate perpendicular to the main shaft. The vertical spindle can rotate freely about its own axis.
The material moves downward between the two surfaces that are gradually crushed until it is small enough to fall out through the gap between the two surfaces. Rotary crusher can be used for primary or secondary crushing.
Cone crusher consists of crushing cavity, crushing cone and operating mechanism. The cone is built into the vertical shaft, which is supported from the top by a bowl-shaped bearing and from the other end to the eccentric operating mechanism.
The operation of the cone crusher is similar to the rotary crusher, the steepness of the crushing cavity is smaller, and the parallel areas between the crushing areas are more. The cone crusher crushes the material by squeezing the material between an eccentrically rotating main shaft (the main shaft is covered by a wear sleeve) and a closed recessed hopper (the recessed hopper is covered by a manganese recess or a bowl lining). When the material enters the top of the cone crusher, the material will be wedged and pressed between the shell and the bowl-shaped lining or recess. Large pieces of material are shattered once, then descend to a lower position (because they are now smaller), where they are shattered again. Continue this process until the pieces are small enough to fall through the narrow opening at the bottom of the crusher.