Ring Die Pelleting Machine
Model: HP-450/HP650
power(kw) 30+2.2/45+4
capacity(t/h) 1-5/5-8
Ring Die Pelleting Machine
A ring die pellet mill is a machine that extrudes powdered feed into pellets, and it is widely used in the feed processing industry. This equipment uses the principle of die-roller extrusion molding. Through the relative rotational motion of the ring die and pressure rollers, the conditioned powdered material is extruded into the die holes and formed. After being cut by a cutter, uniform pellets are obtained. Ring die pellet mills are characterized by their compact structure, attractive appearance, high output, low power consumption, ease of use, and reliable operation.
Component Composition and Functional Zoning
From the perspective of production technology, the ring mold granulator can be divided into the following functional units:
(1) Feeding unit: composed of speed-regulating motor, reducer and auger. By adjusting the speed of the stepless speed regulating motor, the appropriate material flow rate is obtained.
(2) Conditioning unit: including agitator and steam system. The materials are mixed with steam for conditioning, and if molasses or oil is needed, they are also added here.
(3) Granulation unit: including ring die and pressure roller. The ring die is hollow cylindrical with a number of circular through holes drilled radially; the outer surface of the pressure roller is mostly processed into a rack shape. This is the core station for material forming.
(4) Cutting unit: includes a cutter fixed on the outside of the ring die. It is used to cut the columnar material extruded from the die hole into particles of a certain length.
(5) Transmission and control unit: including main motor, reducer, transmission shaft and gear system.
Production line roles and processes
Ring die pellet mills play a core role in the pelleting process of feed and organic fertilizer production lines. The complete feed pelleting process is as follows: raw material crushing → ingredient mixing → conditioning (steam) → ring die pelleting → cooling → crushing → screening → packaging.
In feed production, compounded feed powder enters the feeding auger from the hopper, is conditioned by steam in the conditioner, and then enters the pressing chamber through the feed chute. Under the extrusion action of the ring die and pressure rollers, columnar pellets are formed. The freshly formed pellets are generally between 75-90℃ and have a moisture content of about 17%. They need to be cooled by a cooler to reduce the temperature and moisture content to the specified requirements. Finally, they are screened to obtain qualified products. In biomass fuel and organic fertilizer production, the process is relatively simplified, usually eliminating the need for steam conditioning and proceeding directly to pelleting.
Granulation process and stages
The pelletizing process of a ring-die pellet mill can be divided into the following stages:
Conditioning stage: Powdered material is thoroughly mixed with steam in the conditioner. After conditioning, the material's moisture content should ideally be between 15% and 16.5%; a practical test is to squeeze the material into a clump by hand—it should hold its shape but crumble when released. Conditioning causes starch granules to begin gelatinizing under appropriate temperature and moisture conditions, thereby enhancing the material's binding properties.
Feeding and distribution stage: The conditioned material enters the compression chamber via a feed chute. Centrifugal force generated by the high-speed rotation of the ring die carries the material into the wedge-shaped compression zone formed between the ring die and the press rollers.
Compression and forming stage: Under the compressive force exerted by the die and rollers, the material is compacted and forced into the die holes. Inside the die holes, the material passes through two phases: a deformation/compaction zone and an extrusion/forming zone.
Cutting and discharge stage: The cylindrical material extruded from the die holes is cut into pellets by a cutter.
Pre-conditioning and material preparation
The conditioning process at the front end of the ring die pellet mill is crucial to the pelleting effect. Conditioning involves introducing steam into the material to regulate its temperature and humidity, thereby improving pelleting characteristics. Before conditioning, the material moisture content should generally be below 13%; after conditioning, the suitable moisture content should be between 15% and 16.5%. The conditioning temperature typically reaches 64-85℃. When the conditioning moisture content exceeds 18%, the material is prone to slipping between the inner wall of the ring die and the pressure rollers, and pellets may not even be formed. If the conditioning moisture content is below 14%, pellet formation is difficult, and the pulverization rate is high. Conditioning gelatinizes starch and denatures proteins, which not only improves the adhesion and durability of the pellets but also kills pathogenic microorganisms in the material.
Operating procedures and key control points
Standardized operation of the ring die pellet mill is crucial for ensuring pellet quality and equipment longevity. The core operational principles are: "slow startup, steady feeding, frequent monitoring, and complete emptying."
Pre-startup preparation: Check that the ring die is securely installed and the gap between the rollers and the inner wall of the ring die is within the normal range; check the tension of the V-belts; verify sufficient lubrication at all lubrication points; and confirm that the iron removal device is functioning correctly.
No-load trial run: Operate the machine without load for 3–5 minutes before starting production to check for abnormal noises in the motor or bearings and to ensure smooth operation of the drive components.
Loaded operation: Gradually introduce feed material and adjust the gap between the rollers and the die based on pellet formation quality; the standard gap is typically maintained between 0.1 mm and 0.3 mm. During production, continuously monitor the main motor current and conditioning temperature, adjusting the feed rate or steam addition as necessary.
Shutdown procedure: The shutdown sequence is the reverse of the startup sequence; shut down the relevant equipment in the order dictated by the process flow. Ensuring that the ring die holes are filled with an oily mixture before shutdown is a key factor in extending the service life of the ring die.
Application Effectiveness and Industrial Contribution
Ring-die pellet mills demonstrate outstanding performance in the production of animal feed and organic fertilizer. In the feed processing sector, the ring-die pellet mill is a primary piece of machinery for producing pelleted feed, and its performance largely determines processing output. Characterized by high output and low energy consumption, the equipment meets production needs ranging from one thousand to tens of thousands of tons annually. The high-temperature conditioning process during pelleting eliminates common pathogenic microorganisms and parasites, thereby enhancing the hygienic safety of the feed. The moisture content of the finished pellets remains essentially the same as that of the raw material, facilitating storage and transport. In the biomass energy sector, ring-die pellet mills convert agricultural and forestry waste into high-density fuel pellets, enabling the value-added utilization of resources.
| Model | HP-450 | HP-650 |
| Capacity (t/h) | 2-5 | 4-8 |
| Pelleting Rate (%) | >95% | >95% |
| Motor Power(Kw) | 30+1.5 | 55+3 |
| Dimension(mm) | 2150*1350*2200 | 2500*1350*2535 |
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