1. The distinctive feature of jaw crusher is the two plates which open and shut like animal jaws. The jaws are set at an acute angle to each other, and one jaw is pivoted so that it swings relative to the other fixed jaw. Material fed into the jaws is alternately nipped and released to fall further into the crushing chamber. Eventually it falls from the discharge aperture.
2. Jaw crusher is mainly used as coarse crusher and medium crusher in mining, building materials, infrastructure and other sectors. According to the width of the feed opening, there are three types of jaw crushers: large machines with feed opening width greater than 600MM, medium machines with feed opening width 300-600MM and small machines with feed opening width less than 300MM. Jaw crusher is simple in structure, easy in manufacture and reliable in work.
3. Jaw Crusher is the traditional product in crushing and beneficiation plants, it is suitable for crushing a variety of soft and hard ores and rocks. PEF series are for primary crushing, while PEX series are for secondary crushing. Primary Jaw Crusher and Secondary Jaw Crusher are two main types.
Primary Jaw Crusher
Secondary Jaw Crusher
Jaw crusher working Principle
A jaw crusher uses compressive force for breaking of particle. This mechanical pressure is achieved by the two jaws of the crusher of which one is fixed while the other reciprocates. A jaw or toggle crusher consists of a set of vertical jaws, one jaw is kept stationary and is called a fixed jaw while the other jaw, called a swing jaw, moves back and forth relative to it, by a cam or pitman mechanism, acting like a class II lever or a nutcracker. The volume or cavity between the two jaws is called the crushing chamber. The movement of the swing jaw can be quite small, since complete crushing is not performed in one stroke. The inertia required to crush the material is provided by a weighted flywheel that moves a shaft creating an eccentric motion that causes the closing of the gap.
Crushing ratio is an important evaluation index of jaw crusher. The crushing ratio of jaw crusher is the ratio of raw material size to crushed product accuracy. It indicates the degree of reduction of raw material after crushing. After the stones are crushed, the particle size becomes smaller. The crushing ratio indicates the reduction multiple of particle size after the stones are crushed.
1. Low noise and less dust.
2. Large crushing ratio and uniform product size.
3. Simple structure, reliable work and low operating cost.
4. Safe and reliable lubrication system, easy replaceable parts, simple maintenance.
5. Deep crushing cavity, no dead zone, which improves the feeding capacity and output.
6. Energy saving, saves power of 15%-30% for single machine.
7. Large adjustment of discharge opening range, which can meet the requirements of different users.
Key parts of the jaw crusher
1. Main frame
Jaw crushers are extremely heavy-duty machines and hence must be robustly constructed. The main frame is often made from cast iron or steel, connected with tie-bolts. It is often made in sections so that it can be transported underground for installation. Modern jaw crushers may have a main frame of mild steel plate welded together.
2. Jaw plates and cheek plates
The jaws themselves are usually constructed from cast steel and are fitted with replaceable liners, made from high manganese steel, or Ni-Cr alloyed cast iron. Apart from reducing wear, hard liners are essential in that they minimize crushing energy consumption, reducing the deformation of the surface at each contact point. They are bolted in sections on to the jaws so that they can be removed easily and reversed periodically to equalize wear.
Cheek plates are fitted to the sides of the crushing chamber to protect the main frame from wear. These are also made from hard alloy steel and have similar lives to the jaw plates.
3. Transmission shaft
The eccentric shaft is the main shaft of the crusher, which is subject to huge bending and torsional force and is made of high carbon steel. The eccentric part must be processed precisely with heat treatment, and the bearing liner is cast with babbit alloy. The eccentric shaft is equipped with a pulley at one end and a flywheel at the other end.
Factors affecting the capacity
1. Hardness of the material. The harder the material is, the more difficult to crush them, and the more serious the wear and tear on the equipment.
2. Composition of the material. The more fine particles contained in the raw material, the more it affects the sand making process, because these fine particles are easy to adhere and affect the conveying.
3. Required fineness of the crushed material. The smaller discharged material, the lower processing capacity.
4. Viscosity of the material. The greater viscosity of the material, the easier it will adhere. Materials with high viscosity will adhere to the inner wall of the crushing chamber in the jaw crusher, which will affect the working efficiency.
5. Humidity of the material. When the moisture contained in the material is large, the material is easy to adhere in the jaw crusher, and also easy to cause blockage in the conveying process, it will reduce the process capacity of the total crushing plant.