Flat die pelleting press

Our company produces flat die pelletizing presses. Our presses are designed to produce quality products in varying types of wood.

Flat chopper is used for  extrusion agglomeration . Extrusion agglomeration using a flat (chopper) disc is proven to be an economical method, even for the hardest wood chips. The final product is called a pellet. Grinder rollers and perforated chopper are important elements in pelletizing process. Roughly pre-crushed products are fed vertically from the top to the pressure rollers and form a layer of product on the disc. On top of the top, the rollers run over this layer and compress the material

Процес на пресоване на пелети в плоска матрица
Flat chopped pellet press process

Compression occurs in cylindrical holes on the disc

  • Roll under hydraulic pressure, move to the left
  • Material to be pelleted on disc spread from above
  • Compressed material inside holes tap
  • Blade cut to the desired length throws down the pellets

When the material is rounded into the holes, the pressure is continuously increased, so that the cylinder formed by the particles is disengaged in the holes, downward. To achieve this, the frictional force of the pellets in the holes must not exceed the effective pressure force of the rollers. In order to provide better pre-compression and product bonding, a press is formed between the mold and the rollers to prevent metal-to-metal contact, which can cause unnecessary wear of the discs and rollers. The cylinders run through each hole several times per second, so that the pellets progress through the holes in the apertures.

The individual layers of material forced into the effective holes of the die form an endless strand cut to the desired pellet length from below using adjustable knives. The aim is to produce a homogeneous pellet Which does not exhibit a layered structure with the stability left unchanged even after exposure to mechanical stress. The achievement of this goal is influenced by many factors, as follows:

Compression rate of material (F force adjustment)
Moisture content of the material to be pelleted
In steam treatment, amount of steam
Number and size of rolls
Disc diameter and effective number of holes
The length, diameter and physical shape of the holes
Distance between rolls and disc "h"
Drive motor power
Speed of Cylinders
Pellet drying
Pellet cooling

Pellet Press Parts Description:

  1. Feeding
  2. Intelligent material router
  3. Hydraulic press system
  4. Roll Head
  5. Rolls
  6. Disc (Horizontal pellet maker)
  7. Main shaft
  8. Sliding blade system
  9. Main body
  10. Pelet outlet port
  11. Reductor
  12. Motor
According to the pelleting properties of the material to be pelleted, the disc diameter, the perforated surface area and width of the disc, the number of discs may vary.

Material Feeding

The material is fed directly to the printing machine vertically from above, without any deflector and without the use of mechanical aids. Therefore, in materials such as sawdust, which have a particularly low bulk density, there is no danger of clogging or bridging due to the uneven distribution. Our presses have a large feeding area especially for materials with low bulk density suitable for wood sawdust.

Roll Head

The roller head forms a unit consisting of roller axles and rotating upright grinding rollers. The number of holes, diameter, width, shape (cylindrical or conical) and the roll surface are selected to best fit the material to be pelletized. The average roll speeds of 2.4-2.6 m / s are an average speed. The hydraulic roller head adjustment system (see Figure 3) makes it possible to optimize the distance between the rollers and the disc during operation. Therefore, the thickness of the material layer can be adjusted so that the most economical pressing capacity can be achieved.

Figure 3: Hydraulic disk grinder cylinder

Adjustment system operation

  • The space between the rollers and the disc is set to “h”
  • Hydraulic pressure pressure is set to “F force”
  • Pressure is supplied
  • Pellet material is fed from the top.


  • If the motor load is too much, the pellet supply is reduced
  • If load is low, feed pellet is increased
  • If the motor is overloaded, press automatically stops and goes into failure
  • Print pressure, speed is adjusted again.

The hydraulic pressing system makes it possible to change the distance between the rollers and the die during operation. In this way the thickness of the product layer can be adjusted and the operation is not interrupted.

Disc thickness, number of holes, shape and diameter and width of the roller path may vary depending on the material to be processed. A high specific print output with low energy consumption per unit is among the other things that are greatly affected by the time the material is retained in the effective holes. The shorter the retention time, the lumps become softer, etc., the higher the output, the lower the pellet quality. To avoid this, the length of the effective motors can be extended until the full motor power is consumed. The longer the holes, the greater the risk of clogging the rollers. Therefore, it is preferable to maximize the number of disc holes so as not to break the pressure force. The disc perforated portion area varies from 15 to 30 cm2 per kW of installed power depending on the type of material to be pelletized, the intended use and the desired material jam.

The disc is supported all around the press casing and held in place by the wedges only. This minimizes the risk of mold breakage.

The roll head is loosely seated on the main shaft and is connected to the disc body by means of clamps. The roll head is held with adjustable hydraulic nuts from above. Therefore, the molds are very easy to change and quick, because no screws or clamps are required to be loosened except for the hydraulic nut. The roll head and the disc can be easily removed by means of an electric winch and can be replaced without having to clean the interior.

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