The Influence Of The Hammer Mill In Making Quality Pellets

Most people think that pellet making is just down to the pellet mill. While the pellet mill obviously plays a crucial role, what is also highly significant is the quality of material you feed the pellet mill. Material moisture content is a key point, and precise consistent control can reward you with producing better quality pellets with produced production costs. However there is another key factor, the size of the particles and the hammer mill. The hammer mill is used for final size reduction. Material input for the hammer mill must be below 1 cubic inch, therefore a chipper or shredder is often used before the hammer mill. Within the hammer mill there is a screen which can be changed. The holes of the screen normally relate to the diameter of pellet you wish to produce. So for instance if you were producing wood pellets for pellet boilers you may be using an 8mm pellet mill die, you would therefore be using a 6mm screen. General rule the particles need to be below the diameter of the pellet die diameter. While this is the case with a 6mm screen, some particles will be larger than this. The reason is simple, some particle may have a diameter lower than 6mm, but their length could be much longer. You want to reduce this as much as possible, therefore we generally use a 4-5mm screen in the hammer mill no matter what diameter of pellets we are making. This reduces the issue of rogue over sized particles, however it also has another benefit. Pellet compression is about getting heat into the particles to melt the natural lignin, and this is much easier with a smaller diameter particle. However by this logic you may think why not use a 1mm or 2mm screen. Well first this would dramatically reduce the productivity of the hammer mill. Secondly it also creates potential issues for the pellet mill. Remember in the pellet mill the rollers and die should not touch there should be about a 1mm gap. Therefore the pellet mill finds it difficult to compress very small particles through the die holes. They will not compress through the die.

 The Wood Pellet Mill Production Guide © PelHeat Ltd - The Influence Of The Hammer Mill In Making Quality Pellets