Coal crusher

Coal crusher is a core specialized equipment in coal transportation systems of thermal power plants, coal chemical industry, coal mines, metallurgy and other industries, responsible for the crushing and pretreatment of raw coal. It is known as the particle size control center of coal transportation systems. Its core function is to crush raw coal (conventional feed particle size ≤ 300mm, heavy-duty models can adapt ≤ 800mm) to the qualified particle size required by downstream coal mills and boilers (mainstream thermal power requires discharge particle size ≤ 20mm, circulating fluidized bed boilers require ≤ 10mm, particle size qualification rate ≥ 95%), while cooperating with the pre iron removal device to intercept and discharge hard impurities such as iron blocks and gangue in the raw coal, protecting downstream precision equipment such as coal feeders and mills from impact damage from the source. It is a key equipment to ensure stable coal supply system and efficient combustion of boilers.

1、 Core working principle
The coal crusher is based on four core crushing methods: impact, shear, extrusion, and grinding. Different models are adapted to differentiated crushing logic: the mainstream ring hammer coal crusher relies on a high-speed rotating rotor to drive the ring hammer, which performs high-frequency impact and impact crushing on the raw coal, and cooperates with the shearing and grinding effects of the sieve plate to achieve particle size control; Qualified materials are discharged through the gaps in the sieve plate, and large pieces of materials are retained in the crushing chamber for continuous crushing until they meet the standards; At the same time, the avoidance structure can automatically discharge iron blocks and other unbreakable debris to avoid equipment damage.

2、 Classification and Core Features of Mainstream Models
There are three main types of coal crushers commonly used in coal transportation scenarios, among which the ring hammer type is the absolute main model in the thermal power industry. The core parameters and adaptation scenarios are shown in the table below:

Table

3、 Core structure composition (ring hammer coal crusher, mainstream thermal power models)
1. Rotor assembly (core working component of equipment)
The rotor is the power execution core of the coal crusher, consisting of a high-strength alloy steel main shaft, hammer disc, spacer sleeve, ring hammer, and ring hammer shaft. The ring hammer can revolve with the rotor and rotate around the hammer shaft to improve crushing efficiency; Before leaving the factory, the entire machine needs to undergo strict dynamic balance verification to ensure that the operating vibration value is ≤ 0.025mm. The ring hammer is made of high chromium wear-resistant alloy material and has a service life of not less than 3000 hours.
2. Body and crushing chamber
Composed of upper and lower casings, wear-resistant lining plates, crushing plates, impact plates, and iron removal chambers, the casing is welded with thick steel plates and has high strength, earthquake resistance, and sealing and dust prevention characteristics; The inner wall is embedded with high manganese steel wear-resistant lining plate, which can be replaced and maintained; The iron removal chamber is used to collect and discharge unbreakable debris such as iron blocks to avoid equipment jamming and damage.
3. Drive and transmission system
Composed of a driving motor, hydraulic coupling/permanent magnet coupling, reducer, and elastic coupling, it can achieve soft start and overload protection, adapt to heavy-duty start stop and continuous operation conditions, effectively buffer starting impact, and avoid motor burnout; Explosion proof models can be adapted to high-risk scenarios such as underground coal mines.
4. Screen plate and gap adjustment mechanism
Composed of coal crushing plate, arc-shaped sieve plate, sieve plate frame, and adjusting mechanism, the sieve plate is made of wear-resistant manganese steel material. The gap between the sieve plate and the ring hammer can be flexibly adjusted through the adjusting mechanism to accurately control the discharge particle size; The sieve size can be customized according to downstream process requirements, with a conventional aperture of 10-30mm.
5. Safety protection and auxiliary systems
Equipped with shock absorber base, hydraulic door opening mechanism (convenient for maintenance), temperature monitoring device (bearing overheating alarm), vibration monitoring device, blockage alarm device, and dust removal interface, it can achieve full working condition safety protection and intelligent monitoring.

4、 Core technical parameters (mainstream ring hammer coal crusher)
Compliant with JB/T 8911-1999 "Ring Hammer Crusher" and DL/T 512-2014 "KRC Series Ring Hammer Crusher" power industry standards, the mainstream selection parameters are as follows:

Table

5、 Core advantages of the product
Strong adaptability to working conditions and wide compatibility with coal types: it can adapt to various types of raw coal with a moisture content of ≤ 15%, without fear of high ash content, high gangue and poor quality coal. The ring hammer type machine can achieve crushing under both dry and wet working conditions, without the risk of material blockage, and can operate continuously and stably for 24 hours.
High crushing efficiency and excellent product quality: With a large crushing ratio, a single device can complete coarse and medium crushing of raw coal, reducing the number of system equipment; The discharge particle size is uniform and controllable, with a low over crushing rate, effectively improving boiler combustion efficiency and reducing fuel consumption.
Safe and reliable, easy to maintain: equipped with overload protection and automatic debris discharge function, which can effectively avoid equipment jamming and damage; The standardization level of vulnerable parts is high, and the replacement of components such as ring hammers, screen plates, and lining plates is convenient. The hydraulic door opening mechanism greatly reduces the difficulty of maintenance and shortens downtime.
Energy saving and environmentally friendly, high degree of intelligence: fully sealed structural design, no dust overflow, in line with environmental emission standards; Equipped with an intelligent monitoring system, it can monitor bearing temperature, equipment vibration, and discharge particle size in real time, achieve early warning of faults, and can be connected to the power plant DCS centralized control system to achieve remote fully automatic control.

6、 Common faults and core maintenance
Core common faults: wear and tear of ring hammer/plate hammer, blockage/damage of sieve plate, unbalanced vibration of rotor, overheating of bearings, powder leakage of machine body, and blockage of feed inlet.
Core maintenance points: Regularly check the wear of vulnerable parts, replace the ring hammer in a timely manner when it is worn to 2/3 of its original thickness, and symmetrically balance the weight to ensure rotor balance during replacement; Regularly clean the coal and debris stuck in the gaps of the sieve plate, and calibrate the gap between the sieve plate and the ring hammer; Regularly add bearing grease and monitor temperature and vibration values; Regularly verify safety protection devices to ensure sensitivity and reliability.

7、 Applicable scenarios
Core scenarios: Coal crushing system in thermal power plants, large-scale open-pit/underground coal mine preparation plants, raw material crushing in coal chemical projects, coke crushing in coking plants, and coal crushing in metallurgical sintering plants.
Expanding scenarios: Fine crushing operations of medium and low hardness brittle materials such as limestone, gypsum, and slag in the building materials and chemical industries.