A crusher is a piece of mechanical equipment that is mainly used to break down the material into small particles. This is done so that the transportation of the material becomes easier. A jaw crusher consists of two jaws, one of which is movable, while the other is fixed. Jaw crushers are mainly used to break the elements that are approximately 1.5 m to 2.4 m in size into smaller particles. The size of the resultant crushed particles goes up to approximately 25 mm. Some of the major elements that can be easily broken with the help of a jaw crusher include coal, rocks, etc.
Working Principle of a Jaw Crusher
A jaw crusher mainly works on the principle of reciprocating motion exhibited by the moveable jaw of the jaw crusher. The repeated movement of the jaws results in the development of compression force that further causes the breakdown of the rock or the ore placed between the two jaws into smaller pieces. The movement of the jaw crusher is typically known as the chewing movement of the machine.
Working of a Jaw Crusher
The material to be broken with the help of a jaw crusher is fed between the two mechanical jaws. The fixed jaw, as the name suggests, is stationary and does not get displaced from its original position. The main task of the fixed jaw of the jaw crusher is to hold the material to be crushed in place so that it does not slip when the force is applied. The movable jaw exhibits a periodic to and fro motion and generates the necessary force to break down the object into small pieces. The angle between the moveable and the fixed jaw is roughly set to 20 or 30 degrees as it provides an appropriate amount of space to perfectly contain and capture the material in between the jaws. The motor relays the input power to the pitman. The pitman is further connected to the flywheel. The force generated by the motor causes the flywheel to move and helps to transfer the power to the shaft. The moveable jaw connected to the shaft is, therefore, starts to move and exhibit a reciprocating motion. The moveable jaw moves approximately 250-400 times per minute. The material inserted between the two jaws of the jaw crusher is, therefore, subjected to a significant amount of compression force. This compression force is mainly responsible to break the huge blocks of substances into smaller pieces. One of the main security issues that arise while using jaw crushers is that the small pieces of the crushed material tend to scatter in the surrounding. This random motion of the broken particles with a relatively high velocity may cause severe injuries to the person operating the machine or standing near the machine. To avoid any mishap, a protector is formed over the inlet opening of the machine that covers the gap between the jaws and restricts the movement of the smaller crushed particles.
Types of Jaw Crushers
A jaw crusher can be classified into two broad categories, namely, a single toggle jaw crusher and a double toggle jaw crusher.
Single Toggle Jaw Crusher
A single toggle jaw crusher consists of an eccentric shaft that is placed on the top of the crusher. The rotation of the shaft along with the toggle plate generates the necessary compression force required to break down the substance into smaller particles. A single toggle jaw crusher has a better capacity than a double toggle jaw crusher.
Double Toggle Jaw Crusher
A double toggle jaw crusher consists of two shafts and two toggle plates. The first shaft is the pivoting shaft on the top of the crusher, whereas the other shaft is the eccentric shaft that is used to drive both the toggle plates.
Advantages of a Jaw Crusher
1. Jaw crushers are comparatively inexpensive.
2. Both the structure and working of a jaw crusher are quite simple.
3. The product size is quite small and can range up to millimetres.
4. Repair and maintenance of a jaw crusher are convenient and easy.
5. The reliability of a jaw crusher is significantly high.
6. The broken parts of the jaw crusher are easy to replace.
Disadvantages of a Jaw Crusher
1. The crushed material sometimes gets stuck between the jaws, and the machine gets jam. This can be resolved by loosening up the spring attached to the base of the jaw crusher, dislocating the entire set-up, removing the stuck particle, and reconfiguring the machine.
2. If the safety protocols are not properly followed, the breakdown of material into smaller particles may cause severe injuries and accidents.
3. The resultant products obtained after crushing are uneven in size.
4. Jaw crushers are bulky and produce vibrations.
5. The productivity of a jaw crusher is quite low.
6. The range of the jaw is a constraint; therefore, only a confined amount of material can be fed to the machine.
7. The moveable jaw of the jaw crusher is highly susceptible to undergo wear and tear.
Uses of a Jaw Crusher
Mining
A jaw crusher is typically used in the mining of elements such as coal. It is used to break down the large blocks of coal or other elements into smaller particles to ease the transporting.
Metallurgical Industry
The metallurgical industry mainly deals with the study of the physical and chemical properties of elements, compounds, and alloys. A majority of metallurgical tasks require the breaking down of substances into smaller particles. For this purpose, jaw crushers are primarily employed.
Construction
Carrying construction material from one place to another is difficult. This can be simplified by transporting the material after crushing it into smaller pieces with the help of a jaw crusher.
Chemical Industries
A number of chemical industries extract pure forms of elements from their rocks. For this purpose, the rocks are crushed into smaller pieces with the help of jaw crushers. Then the smaller particles of the rocks are subjected to chemical reactions, and the pure form of the element is successfully extracted.
