09 Dec 2021
Everything you need to know about Cone crushers is right here
The Cone Crusher Encyclopedia
An ever present and important engineering equipment in the crushing plants, a cone crusher is an instrumental equipment for uniform and high capacity with single unit in any crushing set up. A machine operates by Compressing the feed material in between two surfaces of castings one moving and the other stationery. This crushing is usually aids the crushing than only impacting in most engineering processes and helps in making the material. To get 4-5 times reduction in sizing and the product can be used / moved to next step of crushing
How exactly does it work?
Feed from the vibro feeder is regulated and controlled into the in-built hopper at the top of the cone crusher. Gravity does its work and finds its way to the bottom. The material is compressed in between oscillating or rotating mantle and the fixed concave in the crushing chamber. Inter particle crushing also improves the crushing action as the feed moves towards the bottom of the Cone Crusher. The product is discharged through an opening in the bottom shell.
The crushing action is produced by the oscillating motion of the mantle, and it compresses the material between the mantle and concave part of the crushers.
It is important to know that due to the eccentric motion of the mantle, the gap between the mantle and the concave are different as well. The smallest gap is called closed size setting (CSS) and the bigger gap the open side setting (OSS). When the gap between the mantle and concaves is at its largest, the opposite side gap is at its smallest. These settings are important because they describe the largest possible product size output (OSS) and smallest possible product size output (CSS). As the mantle oscillates the OSS will become CSS and vice versa. This ensures that the feed is crushed on one side and the product is released on the other side.
The aforementioned eccentric motion is achieved by the eccentric bush with different thickness. The bearings support and drive the arrangement at the bottom of the main shaft through the gear and pinion drive countershaft which is supported by the bearings. This is powered by an electric motor. Through pulleys and a belt drive arrangement the speed can be reduced at the crusher.
The inner surface of the eccentric bushing is machined off-centre from the centre-axis of the crusher. As the bushing rotates, the main shaft oscillates in an elliptical orbit around the centreline of the crusher. This action causes the gap between the mantle and concave liners to open and close upon each rotation of the shaft. At the upper end of the mantle this movement is very small, but as the feed falls lower, the throw increases and the crushing force also correspondingly increases.
The main shaft floats with two bearings at the bottom and one bearing at the top. The shaft is supported in the oil chamber with a Hydraulic pump to move it up and down by varying the oil content in the chamber. Also, the uncrushable material creates pressure on the oil and this will push the oil to the accumulator and aid for tramp release.
The crushed product falls to the bottom shell and is discharged to the product conveying system for further processing.
These magnanimous cone crushers are capable of crushing all types of material including hard mineral rocks and stones. The cone crushers have proven to exhibit multiple advantages over other crusher designs, such as having low energy consumption, reliability, high efficiency (compared to other crushers) and a high reduction ratio too.
Despite being present in many industries, it is most commonly used in the construction and mining industries. Cone crushers are generally found in use for secondary, tertiary and downstream crushing services.
What are the various components of a cone crusher?
The main components of a cone crusher include the top body, concave ring, main shaft assembly with dead centre , mantle, eccentric bushing, drive, crown gear, frame, accumulator (tramp release) mechanism and the main body.
Let’s individually look at some of the pieces to understand the incredible equipment better.
The feed is fed into the crusher’s feed bin by conveyors located above the vertically mounted cone crusher. The feed then enters the crusher via an opening in the upper shell and depending on the cone crusher design, the feed material falls on the distribution plate, used to distribute the feed evenly, as it enters the crusher.
The main shaft is normally manufactured from high grade forged steel. The upper part of the shaft is supported with roller bearing. The self-aligning of the main shaft caters to the movement generated by the oscillating shaft. This oscillating movement is caused by the lower eccentric drive arrangement.
Mantle and Concaves
A mantle is installed over the cone, mounted onto the main shaft. The mantle forms parts of the replaceable surfaces and it oscillates with the moving shaft. The concave ring is housed within the upper casing and it forms the stationery surface.
Eccentric Drive and Bushing
Eccentric motion is achieved by the lower eccentric bushing which is being supported with the bearings and drive arrangement located at the bottom of the main shaft. The arrangement is similar in design and principle to that used by the oscillating crusher. It is possible to adjust the eccentric throw by installing different sized sleeves. The throw defines the range of movement and consequently the distance between the mantle and bowl liner. This is relevant at the choke point.
Pinion Gear and Counter Shaft Assembly
An alloy steel pinion gear is mounted onto a pinion drive shaft. This is supported by the pinion shaft bearings fed from a common lubricant system. An external motor pulley arrangement provides power to the pinion shaft, which inturn rotates the main shaft.
An annealed cast steel bottom shell houses the drive arrangement and eccentric drive components. The discharged material from the crusher passes through this bottom shell.