A hammer mill is a type of equipment that crushes materials by impact. It is classified into two types – single rotor and double rotor. It is primarily used to crush materials with a maximum particle size of 600-1800 mm down to 25 mm or less. Hammer mills are suitable for medium-hard and fine crushing of materials such as limestone, slag, coke, coal, and other industrial sectors, including cement, chemical industry, electric power, and metallurgy.
The hammer mill has rows of hanging hammers on its main shaft, each hinged with a pin shaft. The hammer’s working surface can be replaced when worn. Two trapped pin holes on the hanging hammer body adjust the gap between the hammer and the grate bar. The rotor’s ends are supported on rolling bearings and connected to the motor with an elastic coupling. A flywheel is installed at one end of the main shaft for smooth rotor rotation.
An arc-shaped discharge screen bar is installed below the rotor. Both ends of the grate bar are mounted on the cross beam, and the outer grate bar is pressed with a pressure plate. The grate arrangement is perpendicular to the rotor’s movement direction. The protruding part in the middle of the grate bars forms the gap between the grate bars, which expands downward and tilts toward the rotor’s rotation direction for material discharge.
A hammer mill is consisted of the wear parts:
The hammer mill’s main working part is the rotor, which consists of the main shaft, hammer disc, pin shaft, hammers, and other components. The disc has evenly distributed pinholes, and the pin shaft is used to suspend the hammerhead. To prevent axial movement of the disc and hammerhead, lock nuts are used to secure the pin at both ends. The rotor is supported by two rolling bearings, which are fastened to the lower body support by bolts. Two positioning pins are fixed at the bearings’ center distance. A flywheel is specially installed at one end of the main shaft to allow the rotor to store kinetic energy during motion, reducing the motor’s peak load and the hammerhead’s wear.
The main shaft is a crucial part of the hammer mill, as it supports the rotor and bears the weight and impact of the rotor and hammers. Therefore, the material used to make the main shaft needs to be highly tough and strong. To achieve this, high-quality alloy steel is used for the main shaft and undergoes ultrasonic flaw detection, quenching, and tempering.
The hammer disc, which holds the hammers, is also an important component of the hammer mill. It is bound to be impacted and rubbed by the ore during the crusher’s operation, so it must be resistant to wear. To improve its wear resistance, the hammer plate and hole are made of high-strength steel and treated with carburization and heat.
The hammer mill’s critical working component is the hammer. The production capacity of the hammer mill is determined by the quality, shape, and material of the hammer. The kinetic energy of the hammers is directly proportional to their weight. Higher hammer weight means greater kinetic energy and higher crushing efficiency. Hammer weights range from 15 kg to 300 kg, and different hammer weights can be customized as per customer requirements. The hammer head is made of new high-quality multi-element high chromium manganese steel composite casting, which has a service life several times longer than a general hammer.
The hammer mill crushes ore at high speed using its hammers. The ore gains great speed and kinetic energy instantly. To prevent the frame from being worn out, the side plates are lined with manganese steel, and the impact plates are made of high-strength steel that is cast and quenched. This process ensures superior wear resistance and impact resistance of the side plates and impact plates. The quality of the hammer mill determines its service life due to the harsh working environment. The materials used for its parts determine the quality of the hammer mill.
Hammer mill screens are perforated metal plates or bars that cover the discharge opening of a hammer mill. These screens have openings of various sizes, and their primary function is to control the particle size of the crushed material as it exits the hammer mill.
The configuration of the hammer mill screens influences the final product size and plays a crucial role in determining the efficiency of the milling process.
Qiming Casting produces wear parts for hammer mills that are highly wear-resistant, easy to install, and have a longer lifespan. They achieve this by working closely with hammer mill users to understand their needs.
In addition to standard manganese liners (Mn14, Mn18, Mn22), Qiming Casting also provides wear parts made from various materials to meet their customers’ diverse needs.
Learn more about Qiming Casting manganese steel casting solutions→
Some common problems and solutions for hammer mill parts during machine operation
Analysis: The crusher and motor are installed on different axes.
Solution: Correction and adjustment to meet the technical requirements of installation.
Solution: Control the lumpiness of the material.
Solution: Check carefully and tighten in time.
Solution: Adjust the gap between the rotor and the screen plate.
Download Brochure
Product List