When to Use jaw crusher machine?

15, Jul. 2024

 

Jaw Crusher Advantages and Disadvantages

A Comprehensive Analysis: Jaw Crusher Advantages and Disadvantages

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Jaw crushers are widely used in the mining and construction industry due to their ability to crush hard materials efficiently. They are a primary choice in crushing applications involving various materials like ores, concrete, and more. In this article, we will discuss the advantages and disadvantages of jaw crushers, shedding light on their overall impact on industrial operations.

Jaw Crusher Advantages:

High Efficiency: Jaw crushers provide efficient and rapid material reduction, making them suitable for high-throughput applications.

Versatility: They can handle a wide range of materials, including abrasive and hard stones, ensuring flexibility in usage.

Simple Structure: Jaw crushers have a simple structure, making maintenance and repair relatively straightforward.

Cost-Effective: In comparison to other crushers, jaw crushers are often more cost-effective due to lower initial and operating costs.

Size Adjustment: Most jaw crushers come with adjustable settings to control the size of the crushed materials, offering customization based on specific needs.

Jaw Crusher Disadvantages:

Maintenance Intensive: Although maintenance is simple, it needs to be frequent to ensure optimal performance, especially for heavy-duty usage.

Abrasive Material Wear: Jaw crushers can experience excessive wear on their metal surfaces when processing abrasive materials, impacting their longevity.

Dust Generation: During operation, jaw crushers can produce a significant amount of dust, necessitating proper dust control measures.

Noise Generation: They can be noisy during operation, requiring noise reduction measures for a better working environment.

Limited Feed Size: Jaw crushers have a maximum feed size limitation, restricting the material size that can be effectively processed.

In conclusion, jaw crushers offer numerous advantages, including high efficiency, versatility, and cost-effectiveness. However, they come with certain drawbacks like maintenance needs, abrasive material wear, and noise generation. Understanding these pros and cons is crucial for industries to make informed decisions and optimize their crushing processes accordingly. Regular maintenance and appropriate operational practices can help maximize the advantages while mitigating the disadvantages associated with jaw crushers.

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What Is A Jaw Crusher - MEKA

WHAT IS A CRUSHING PROCESS? / CRUSHING

In order to make use of the rocks or ores obtained through quarrying/explosion in the Mining and Construction sectors, the materials need to be crushed to reduce them to a smaller size. We call this process SIZE REDUCTION or CRUSHING.

The goals of the size reduction are as follows:


1.) Obtaining the size or surface area required for the use of the ore or material
2.) Allowing ease of transportation and storage
3.) Separating the different minerals contained within the ore and to release them from one another
4.) Obtaining the size or surface area required for the enrichment stage.

In general, crushing is carried out in three stages, depending on the desired size of the material.


Primary Crushing

This is the first stage of the crushing process. In general, the size of the feed material, which is between 800 and mm, is reduced to between 150 and 300 mm.

Secondary Crushing

This is the second stage of crushing. Feed size, which is around 150 to 300 mm, of the rock or ore from the primary crushing process is reduced to between 50 and 80 mm.

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Tertiary Crushing

This is the third stage of crushing. The size, which is around 5080 mm, of the ore or rock from the secondary crushing process is reduced to between 5 and 12 mm.

We call the machine that performs the CRUSHING process a CRUSHING MACHINE or CRUSHER.

MEKA Size Reduction Machines

WHAT IS A JAW CRUSHER? / JAW CRUSHER

This is a type of crusher that is widely used in the primary and secondary crushing processes.

It is usually preferred for the crushing of large blocks of hard and abrasive materials.

HOW DO JAW CRUSHERS WORK? / THE WORKING PRINCIPLE OF JAW CRUSHERS

All jaw crushers feature two jaws: one of which is fixed while the other moves. The working principle of jaw crushers is based on the reciprocating movement of the movable jaw that compresses and crushes the rock or ore between itself and the fixed jaw, as the material enters the zone between the jaws.

The moving jaw moves back and forward against the fixed jaw, and material fed from the top of the machine is compressed between the two, breaking it into smaller pieces. As the moving jaw moves away from the fixed jaw, the crushed material is discharged from the crusher at the bottom, with the size of the ejected material determined by the gap between the jaws.

WHAT ARE THE MAIN COMPONENTS OF JAW CRUSHERS? / PARTS AND MAIN PARAMETERS OF JAW CRUSHERS

Jaw crushers are generally defined by their opening size.

For example, a 900x650 mm crusher refers to a crusher with an inlet measuring 900 mm by 650 mm.

The main parts and main technical parameters of a jaw crusher are presented below.

1. Feed Chute
2. Drive Flywheel
3. V-belts
4. Electric motor
5. Motor Stand
6. Settings and Damping Group
7. Hydraulic Cylinder
8. Toggle Plate
9. Swing Jaw
10. Discharge
11. Fixed Jaw

Parts

G: Gape width,
b: maximum feed size,
This is generally desired to be between 80% and 90% of the inlet width
L:  area length
Around double the gape width
W: area width
Varies between 1.3 and 3 times the gape width.
Lmax (OSS): Far side jaw opening (OPEN SIDE SETTING)
Lmin (CSS): Near-side jaw opening (CLOSED SIDE SETTING)

 Parameters

Stroke (LT)

Minimum and maximum movability of the lower end of the jaw. This is equal to the OSS minus the CSS.

R: Size reduction ratio

The ratio of the gape width to the near side jaw opening.
This ratio may vary from 1/3 to 1/9, but is generally 1/3 for  and 1/4 for secondary 

θ: Nip angle

One of the most important parameters is the angle between the two jaws, which is referred to as the nip angle. The nip angle is the angle at which the material, that passes through the  inlet to be between the jaws can be gripped by the jaws without slipping. This angle depends on the size, hardness and frangibility of the material. It cannot be selected as too large or too small. The nip angle in primary  is lower than in secondary 

Generally, this value is between 18 and 24 degrees in primary, and between 22 and 28 degrees in  The nip angle can be 33 degrees maximum.

WHAT ARE THE DIFFERENT TYPES OF JAW CRUSHER? / JAW CRUSHER TYPES

There are two main groups of jaw crushers, categorized according to their jaw movement mechanism.

- Single-toggle jaw crushers
- Double-toggle jaw crushers

In single-toggle jaw crushers, the movable jaw is supported by the bearing on an eccentric shaft driven by the pitman to which it is attached. The pitman is supported by a toggle plate at the bottom of the moveable jaw. Toggle plate compressed between moveable jaw and main body. This mechanism ensures that any point on the moving jaw moves in an elliptical orbit. This mechanism makes a movement aka four bar linkage movement. Through this movement, the movable jaw applies both pressure and friction forces to the material to be crushed.

In double-toggle jaw crushers, the pitman is mounted on fixed non-eccentric shaft that situated at the top of the crusher. There are two toggle plates, one on the left and one on the right, are linked to the pitman that is hinged to the driven camshaft. The toggle plate on the left is linked to the jaw-supporting block, while the one on the right is linked to the main body.

The mechanism of double-toggle jaw crushers allows applying only pressure on the material.

A comparison of jaw crushers with the same capacity reveals that double-toggle jaw crushers are more expensive than ordinary jaw crushers. For this reason, mostly single-toggle jaw crushers are used in the aggregate sector, while double-toggle jaw crushers are used mostly for crushing very hard and highly abrasive materials.

The lifecycle of double-toggle jaw crushers is longer since they do not apply friction force.

References:
Mechanical Eng. Msc Suphi Yavuz, Başak Yavuz Makine, Technical Notes
Mining Eng. Msc Necati Yıldız, Ore Dressing and Enrichment Book

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