Roll crusher

1. Introduction

Roll crushers consist of two or more adjacent rolls placed parallel to each other and rotated in opposite directions. Single roll crushers are also available which rotate a single roll against a fixed breaker plate. Mineral or rock particles placed between the rolls are nipped and then crushed as they pass between the rolls. Rolls are held against each other by springs.

2. Design of Roll Crusher

Two types of roll crushers are generally designed. In the first type, both rolls are rigidly fixed to a frame with provision for adjusting the lateral position of one of the rolls to control the gap between them. Once set these rolls are locked into place. One roll is attached to the driving mechanism while the other rotates by friction. Single roll crushers are also available which rotate a single roll against a fixed breaker plate. In the second type, at least one roll is spring mounted which forms the driving roll, the other roll rotates by friction (following Figure). The nest of springs helps to provide uniform pressure along the length of the rolls. The springs are helical and pressure varies with the size of crusher and could be as high as 6 t/m (about 8300 kPa). In some roll crushers the rolls are individually driven. The drive is either by gears or belt. Both rolls usually rotate at the same speed but some crushers are designed such that one roll could rotate faster than the other. For fine grinding both rolls are rigidly fixed to the base, and therefore, they do not permit any movement of the rolls during operation. The surfaces of the rolls are smooth, corrugated or ribbed. Heavy duty toothed rollers are sometimes used as primary crushers, but the use of such rollers in the metallurgical industry is very limited. Read more

Roll crusher introduction

Brief description of roll crusher

Roll crusher is one of the oldest ore crushing equipment, due to its simple construction, it is still gaining application in cement, silicate and other industrial sectors, mainly used as medium and fine crushing operation of ore. Since this crusher has the disadvantages of large floor space and low production capacity, it is rarely used in metal mines and is replaced by cone crushers. However, in small mines, or processing precious ores, the requirements of the mud is very small re-election plant (for example, tungsten ore) there is the use of roller crusher.

There are two basic types of roll crushers: double roll crusher and single roll crusher.

Double roll crusher (also called twin roll crusher) is composed of two cylindrical rollers as the main working mechanism (Figure 1). When working, the two round rollers rotate in opposite directions, and the material (ore) is crushed by the friction between the rollers, which rolls the material into the crushing cavity formed by the two rollers. The crushed product is discharged from the gap between the two rolls under the action of gravity. The size of the gap determines the maximum size of the crushed product. Double roll crushers are usually used for medium and fine crushing of materials.
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Roll crusher installation, operation and maintenance

Roll crusher installation and empty run test

1. Installation of the roll crusher

The roll crusher should not be stacked for a long time in an unventilated place where it is easy to rust. The roll crusher can be installed on a concrete foundation or on the floor of a building. In order to better withstand the uneven force generated by the machine at work, wooden strips are placed under the bottom frame so that the whole machine fits the strips, and when it comes to the steel plate weld, the strips are shoveled lower in this position so that the strips can also fit the steel plate weld.

For the installation position of the roll crusher, please refer to the layout drawing. The square holes are reserved on the foundation for installing the ground bolts and secondary pouring mortar.

2. Empty run test of roll crusher

(1) Check the relative position between the parts, which should be in accordance with the drawing requirements.
(2) The roll crusher should be tested in empty loading for 4h after assembly.
(3) The rotating parts such as V-belt pulley, gears and rollers should be smooth and no vibration during operation, and the tooth surface of the toothed rollers should not touch the body.
(4) bearing temperature rise shall not exceed 30℃, and the maximum temperature shall not exceed 70℃.
(5) After passing the no-load test run, carry out the test run with load, and the test run time can be carried out according to the system requirements.
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Roll crusher working principle & structure

1. Overview

Roll crusher is an old crushing machine. The main advantages of the roll crusher are: simple structure, compact and light body, low price, reliable work, easy to adjust, less over-crushing phenomenon, can crush sticky wet materials. Because of the above advantages of the roll crusher, there are still some industrial sectors using it, and there are new improvements and developments.

The disadvantages of roll crusher are: low production capacity, requirement for feeding the material evenly and continuously to the full length of the roll, otherwise the roll wears unevenly, and the size of the product is not uniform, which may need frequent repair. For smooth roll crusher, the size of the fed material is much smaller than the diameter of the rolls, so it cannot crush large pieces of material, and it is not suitable for crushing hard materials, either. It is usually for medium and fine crushing of medium-hard or soft materials. Although the toothed roll crusher can clamp into larger materials, it is limited to medium crushing, and the compressive strength of the material cannot exceed 60.8MPa, otherwise the tooth prongs will break easily.

According to the number of rolls, roll crushers can be divided into four types: single-roll, double-roll, three-roll and four-roll; according to the shape of the roll surface, they can be divided into three types: smooth, grooved and toothed roll crushers. The specification of the roll crusher is expressed by the diameter of the roll ø x the length of the roll L.
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