What is Flat Die Pellet Mills?

According to different shapes and sizes, pellet mill or pellet press can be divided into two main designs, one is flat die pellet mill and the other is ring die pellet mill.Flat die pellet mills are also called small pellet mill which are generally used for small pellet production, ring die pellet mills, however, are used to make pellets on a large scale.

Also called small pellet mill, the flat die pellet mill is small in size as the name suggested. Due to their more simple design and operation, this type of pellet maker is much more popular design for small pellet mills. The flat die pellet mill works on vertical principle. Being put from above, raw material drops down into the working area. According to different pellet mill dies, there are two designs of working principles. The first one is stationery die with a set of rotating rollers, the other is stationery rollers with a stationery die. When falling into this area, materials will naturally be compressed into pellet form between roller and die through the die holes.
 

Advantages of Flat Die Pellet Mills:

Generally, there are two main merits of flat die pellet mill. Firstly, compact structure. As we all know, flat die pelleting machines always refer to small pellet mills which means they are small in size and have the character of light, convenient to be moved and easy to be cleaned as well. The other advantage is its visibility. Many flat die pellet mills today are possible to view into the chamber when pelletizing, so you can solve and correct any problem quickly by easily viewing what has happened inside the chamber, that is also to say the flat die design has much more wider material choice.
As to the disadvantage, the greatest one is the wear and tear during the pelletizing process. Rollers’ inner and outer edges covers different distances when rollers rotating across the surface of die. However, pellet mill manufacturers have improved rollers to reduce the wear.

What is Ring Die Pellet Mills？

Ring die pellet mill is another popular design of pellet mills. Different from flat die pellet mills, the ring die pellet mill always used to produce wood pellets on a large scale for light industrial and commercial purposes. Ring die pellet mills are not so popular as flat die pellet mills for the more complicated design and higher costs, but they do have advantages over the smaller design for large scale wood pellet production. As the name suggests, in a ring die pellet mill the die include rollers just like a ring, in another word, the rollers just part of the die, the rollers bring to bear on the inner surface of the die when it start to work. A surge bin is used to put materials through variable speed conditioner then the material will be fed into the pellet mill door. A screw auger, however, will help put materials into the centre of the pellet mill chamber.

Advantages of Ring Die Pellet Mills:

There are also two advantages of ring die pellet mills.First of all, ring die pellet mill generate less wear and tear when pelletizing for the reason that the inner and outer edge of the roller covers the same distance. Secondly, ring die pellet mills are more energy efficient than the flat die design. Roller slip during the pelleting process brings about extra friction, but this extra friction is a good element to produce quality wood pellets for more friction results in more heat.