What Is A Wood Hammer Mill? How Does It Work?

Wood hammer mill is a kind of sawdust making machine. Its main function is to crush large size wood chips into 3-5 mm sawdust for producing wood pellets and sawdust clumps. Compared with blade type wood crusher, it has no blades, but relies on the high-speed rotation of the hammer inside the machine to hit the biomass material and crush the material into fine sawdust.

The wood hammer mill is mainly composed of a casing, a shaft, a hammer, a screen, a wear-resistant liner, an induced draft fan, a cyclone separator, etc.

When the hammer mill is working, the motor drives the shaft to rotate, and the hammers on the shaft also rotate at high speed with the shaft. The wood raw material is fed into the crushing chamber from the feed port and is quickly crushed under the impact of the high-speed rotating hammer. The crushed material reaches the required fineness and is sent to the discharge port by the airflow through the screen. Otherwise, it will remain in the crushing chamber until it is crushed to the required size. For large-capacity hammer mills, we usually equip independent fans to assist in discharging sawdust.

The wood hammer mill uses the impact force of the rotating hammer mill to crush and grind the biomass material into the required size. Generally speaking, if you want to get fine products, the wood hammer mill should be set to a higher shaft speed, a smaller screen and a larger number of hammer mills; if you want to get coarser products, the wood hammer mill should be set to a lower speed, a larger screen and fewer hammer mills. Depending on the material characteristics and production purpose, the shaft speed, screen size and number of hammer mills can be changed individually or in combination to achieve the best comminution effect.

The hammer mill is a highly efficient device that is mainly used to crush various wood and biomass materials into fine particles or sawdust. The following are the types of materials that can be crushed by the hammer mill:

1. Wood
Wood chips: including wood chips and fragments generated from the wood processing process.
Wood chips: larger wood chips can be processed by a wood chipper first, and then crushed into sawdust by a hammer mill.
Bark: bark is also a common raw material that can be crushed by a hammer mill.
Wood chips and chipboard: such as scraps of plywood, particle board, etc.

2. Crop residues
Straw: such as corn straw, wheat straw, etc., can be crushed into fine particles by a hammer mill.
Peanut shells: The shells of peanuts can also be crushed by a hammer mill.
Bean straw: The straw of legumes is also suitable for processing with a hammer mill.

3. Other biomass materials
Nut shells: such as walnut shells, almond shells, etc., are suitable for crushing with a hammer mill.
Grass: Some dry grass materials can also be processed by a hammer mill.

4. Unsuitable materials
It should be noted that the following materials are not suitable for processing with a wood hammer mill:

Sticky or oily materials: such as some materials with high resin or grease content.
Materials with too high moisture content: Materials that are too wet will affect the crushing effect.
Wood with a diameter of more than 4 cm: For wood with a larger diameter, it is recommended to use a wood chipper for preliminary processing.