How To Use Jaw Crusher?

In order to make good use of the rocks or ores obtained through quarrying or explosion in the Mining and Construction sectors. The materials need to be crushed and reduce them to a smaller size. The most common crushing machine is Jaw crusher. It is widely used in the primary and secondary crushing processes. How to use jaw crusher properly? Let's study this artical begining from jaw crusher's working principle, then we will know about jaw crusher's installation, adjustment, maintenance to operation jaw crusher well.

Part 1: How Does A Jaw Crusher Work

A jaw crusher has two jaws like animals chewing jaws: one is fixed jaw and the other is movable.  The two vertical crushing jaws create a V-shaped crushing chamber.  When jaw crusher works, the moving jaw moves back and forward against the fixed jaw, and material fed from the top chamber is compressed between the two jaws, breaking it into smaller pieces. As the moving jaw moves away from the fixed jaw, the crushed material is discharged from discharge opening at the bottom. 

The size of a jaw crusher is measured by the top opening of the crushing chamber. For example, a PE600X900 jaw crusher measures 90mm from one crushing jaw to another and is 600mm across the width of the two jaws. 

Part 2: Jaw Crusher Types

Jaw crushers come in different shapes and sizes to fit different crushing needs. Some of the most common types of jaw crushers used today are single-toggle jaw crushers and double-toggle jaw crushers.

In single-toggle jaw crushers, the moving crusher operates in an elliptical pattern while in double-toggle jaw crushers, a pendulum motion is utilized in order to crush hard materials. The crushing force is generated by the eccentric shaft which is then transferred to the crushing zone by a toggle plate system. Spring pulling rods provide non-positive connection throughout the whole system and heavy loads are compensated by the centrifugal masses on the eccentric shaft.

Because of the angle of deep between the two crushers, the fed material can be reduced significantly upon entering the crushing chamber. The adjustable crusher settings and the suitability of the chosen tooth form for the crushing plates will determine the final size grain distribution of the crushed materials. An adjustable wedge system allows for multiple adjustments of the crusher settings. All parts of the adjusting system can be easily accessed and requires little to no maintenance. The parts can also be replaced in the event that it completely wears out. More details, we could study this artical:  How to adjust jaw crusher gap?

All of the toggle plates used in jaw crushers use replaceable temperature pressure bars that are maintenance-free. A lubrication system is used to ensure adequate grease supply to the bearing points.

From above jaw crusher's working principle and parts fuction, let's to study the jaw crusher installation. Correct installation is an important precondition for good use of jaw crusher machine.

Part 3: How to install jaw crusher?

Jaw crushers are usually installed on concrete foundations. Due to the large vibration of stone jaw crusher, it is necessary to isolate the foundation of the crusher from the plant foundation. When assembling jaw crusher, it is necessary to install jaw crusher frame on concrete foundation first, and then install other components in sequence.

1. Jaw cruser frame installation

When installing the crusher frame, things that can absorb vibration, such as hard wood, rubber, etc., should be placed between the frame and the concrete. The horizontal and vertical levelness of the frame installed on the foundation or wooden base shall meet the installation requirements of the equipment. When the rack is installed, the horizontal and vertical levelness of the foundation should be less than 0.2 mm to ensure that the subsequent installation error does not exceed the installation requirements of the equipment.

2. Eccentric shaft and bearing mounting

Before assembling the shaft and bearing, the sliding bearing needs to be ground, then put it into the sliding bearing seat, and use a level to test its levelness and coaxiality. If the measurement results meet the requirements, install the eccentric shaft on the bearing, and check the fit between the shaft and the bearing by applying red lead powder on the journal. If there are too many high points on the surface of the sliding bearing, further scraping and grinding is required until the high points between the contact surfaces disappear. Finally, a certain amount of lubricating oil should be applied between the bearing seat and the bearing to reduce the wear of the shaft. The contact area between the eccentric shaft sliding and the frame should not be less than 80%, and the gap between them should be less than 0.07mm

3. Toggle plate / bracket mounting

For a long time, jaw crusher's bracket can be disassembled between toggle plate and the supporting liner: loosen the spring nut of the pull rod, remove the spring, and then tie it to the lower part of the movable jaw with a chain or a wire rope, and then pull the wire rope with a crane to make the movable jaw move. When the jaw is close to the fixed jaw, the bracket will fall off automatically. During the installation process, the above steps can be repeated in reverse.

4. Movable jaw plate installationg

The movable jaw  is assembled by pre-assembling the movable jaw parts. After assembling the movable jaw, movable jaw shaft, movable tooth plate and elbow pad on the ground, use a crane or a crane to lift the assembled parts into the frame of the crusher. For sliding bearings, the matching bearings and housings must first be studied so that the sliding bearings can be installed in place. Simultaneously detect the coaxiality and inclination of the sliding bearing assembly to ensure that the inclination is 0.2 mm.

Part 4: How To Operate A Jaw Crusher?

After jaw crusher installation, we must follow the jaw crusher operation precautions as below:

1. Before starting the jaw crusher, start the oil pump motor and cooling system first. After 3-4 minutes, wait for the oil pressure and oil flow indicators to be normal before turning on the motor.

2. After starting, if the jaw breaker makes an abnormal knocking sound, stop the operation immediately, and restart the equipment after the fault is identified and eliminated. After start-up, it should run with no load first, and after a period of time, the feed can only be started when the operation is normal.

3. During the operation, pay attention to the situation that large pieces of material are stuck in the feeding port. If this happens, iron hooks must be used to turn over the material; if large pieces of material need to be taken out of the crushing chamber, special tools should be used. , It is strictly forbidden to operate directly by hand to avoid accidents.

Part 5: Replacement of Jaw Crusher Wearing Parts 

In the jaw crusher, the liner, thrust plate and eccentric shaft are the main wear parts. The following is an introduction to the precautions for the replacement of these wear parts. The fixed jaw liner (tooth plate), movable jaw liner (tooth plate), and both side liners (guard plates) of the jaw crusher are most prone to wear. If the wear is severe, the particle size of the product will become larger.

1. Jaw liner is turned around to reuse

When the liner is initially worn out, the liner can be turned around for use, or the upper and lower pieces can be turned around for use. The wear of the jaw plate is mostly concentrated in the middle and lower parts. When the tooth plate wears off 3/5, it needs to be replaced with a new liner. When 2/5 of the liners on both sides are worn out, they need to be replaced with new ones.

2. Replacement of mandrel, eccentric shaft and bearing bush

If there is not much wear on the shaft and you just want to repair the geometric shape, you can turn it on a lathe. However, when the journal size is reduced by 5% after several turnings, no more turning is allowed and a new one should be replaced. Since the jaw crusher works under impact load, the Babbitt alloy lining on the bearing bush needs to be recast every two years.

If the eccentric shaft and the bearing bush, the mandrel and the bearing bush are worn, and the gap is greater than 1.5 times the original assembly gap, it needs to be adjusted or replaced with pads; the oil groove is worn 1.5mm, and the oil groove should be re-opened and adjusted; the upper cover of the connecting rod head When the gap between the shaft and the eccentric shaft is worn to more than 1.5 times the assembly gap, it also needs to be adjusted with padding or replaced with a new one.

3. Thrust plate replacement

When the thrust plate is severely worn or the front thrust plate is broken, the ore in the crushing cavity must be removed first, and the severely worn or broken thrust plate should be taken out to check whether the movable jaw and the toggle plate on the connecting rod are damaged. Then pull the movable jaw to the vicinity of the fixed jaw, lubricate the working surface of the toggle plate with dry oil, replace it with a new thrust plate, make it slowly contact with the working surface of the toggle plate, and tighten the horizontal pull rod, so that the movable jaw can take the thrust board clamped. Tighten the safety cover, connect the lubrication system, and then adjust the size of the ore discharge port.

Frequently Asked Questions - FAQ

1. Jaw crusher working principle

All jaw crushers work through compression. In a V-shape dalignment, a fixed jaw is thestationary breaking surface. A moveable swing jaw exerts theforce on the material to crush it. The crushed material is discharged from the bottom.

2. Construction of jaw crusher

Jaw crushers are comprised of a fixed plate and a moving plate. High manganese steel is the traditional material used to make the jaw plates of jaw crusher. 

3. Jaw crusher parts and their functions

The real heart of the jaw crusher and its components are the toggle plates, the pitman, and the ply wheel. They generate the crushing action and provide the energy needed to break hard rocks.

1.The flywheel is to generate energy in the form of motion. 

2.Pitman is simply a shaft which is possible to generate a motion whose direction is primarily up and down. 

3.Toggle plates is an arm extending from the pitman. They are set at an angle to the arm and the swing jaw. The movement of the toggle plate forces the swing jaw to be pushed outwards towards the stationary jaw plate to crush stones.

Through the above precautions, we help customers solve a lot of jaw crusher work problems, and extend jaw crusher machine's service. If there are new problems, we welcome you to discuss with Baichy Machinery and solve them together.