Ring Die Pellet Machine
A ring die pellet mill, also known as a ring die pellet mill or ring die pellet feed forming machine, is a pelleting machine that processes powdery or fibrous materials into cylindrical pellets based on the principle of die roller extrusion. This equipment is a key piece of machinery in the production of pelleted feed, and its performance largely determines the feed processing output, playing a crucial role in the feed processing process. The development history of ring die pellet mills can be traced back to the early 20th century—around 1910, the world's first extrusion pellet mill was invented, and around 1920, the first flat die pellet mill was successfully developed. Almost simultaneously, the world's first ring die pellet mill was also invented. After a century of development, the ring die pellet mill has evolved from initially relying on a single rotating roller to extrude materials to pellet mills with two or three rollers, and has abandoned the active roller mode in favor of an active ring die, forming the structure of the ring die pellet mill commonly used today. The equipment can directly press pellets from crushed materials such as corn, soybean meal, straw, grass, and rice husks.
Overall Structure and Core Components
The ring die pellet mill boasts a scientifically precise structural design, primarily composed of five systems:
(I) Feeding System: Composed of a speed-regulating motor, reducer, auger cylinder, and auger shaft. The feeding system employs a mechanically forced feeding method, where material is centrifugally distributed into the pelleting chamber via high-speed rotation. The feeding reducer utilizes a cycloidal pinwheel reducer, effectively controlling the auger speed between 12-120 rpm.
(II) Conditioning System: Includes a conditioner (agitator), where steam is introduced to regulate temperature and humidity, improving pelleting characteristics. The temperature of the conditioned powder can reach 64-85℃, and the humidity 14-16%. If molasses or oil is added, it is added through the agitator along with the steam for conditioning; the amount of oil added generally does not exceed 3%.
(III) Pelletizing System (Pressure Chamber): This is the core working unit of the equipment. The pelleting chamber structure mainly consists of a ring die and pressure rollers. The ring die is a hollow cylindrical shape with several circular through holes drilled radially. The pressure rollers are circular, with their outer surfaces often machined into a rack shape to increase friction between the rollers and the material. There are typically 2-3 pressure rollers, evenly distributed inside the ring die. The ring die is driven to rotate actively by a power source, while the pressure rollers are passively rotated and squeezed by the friction between the material and the ring die.
(IV) Transmission System: This includes the main motor, reducer, drive shaft, and gear system. The transmission mechanism includes a bevel gear connected to the bottom of the main shaft, an angular gear meshing with the bevel gear, and an angular gear shaft that drives the angular gear. Some high-end models use a helical gear reducer transmission structure.
(V) Cutting and Discharge System: This includes cutters fixed to the housing and a discharge port. The columnar material extruded from the die orifice is cut into uniformly long particles by the cutters. Three cutters are typically located on the outside of the ring die.
Applicable fields and industry coverage
Ring die pellet mills have a wide range of applications. In feed processing, this is the primary application area, suitable for processing complete pelleted feed for various livestock and poultry, including pigs, cattle, sheep, rabbits, chickens, ducks, and fish. In organic fertilizer production, they can produce bio-organic fertilizer pellets. In biomass energy, they can produce biomass fuel pellets from various crop straws such as sawdust, rice husks, cotton stalks, cottonseed hulls, and weeds. In the chemical industry, they can be used for pelleting various powdered chemical raw materials. The equipment can also be applied to the grain, food, pharmaceutical, and pesticide industries.
Types of available raw materials
Ring die pellet mills are adaptable to a wide range of raw materials. Feed raw materials: pulverized corn, soybean meal, straw, grass, rice husks, etc. Biomass raw materials: sawdust, rice husks, cotton stalks, cottonseed hulls, weeds, and various crop straws. Fertilizer raw materials: bio-fertilizer, organic fertilizer, compound fertilizer, etc. Other raw materials: household waste, factory waste, etc. The equipment can process pellets with a diameter range of 1.5-12mm.
Operating Principles and Forming Mechanisms
The working principle of a ring die pellet mill is based on die roller extrusion molding. The process is as follows: Powdered compound feed in the hopper is fed into a conditioner via a feeder and an iron removal device. Steam is introduced into the conditioner for conditioning and stirring. The conditioned material enters the pressing chamber through a feeding chute, where a feeding scraper feeds the powder into the pressing zone within the ring die. Due to the centrifugal force generated by the high-speed rotation of the ring die, the material is carried into the conical extrusion zone between the ring die and the pressure roller. As the die roller rotates, the material moves forward more rapidly, and the extrusion pressure and material density gradually increase. When the extrusion pressure increases sufficiently to overcome the friction between the material and the inner wall of the die hole, material with a certain density and binding force is squeezed into the ring die hole. The columnar material extruded from the die hole is cut by a cutter fixed to the casing, forming uniform pellets. Based on the state of the powdered material under die roller extrusion, the pelleting process can be divided into a deformation and compaction zone and an extrusion molding zone.
Core strengths and unique highlights
Ring die pellet mills have the following significant advantages: High output: Single-machine capacity is far higher than that of flat die pellet mills of the same specifications, making them suitable for large-scale industrial production. Low power consumption: Lower energy consumption per unit product, resulting in economical production costs. High pellet quality: Pelletized feed has high density, high hardness, and a smooth surface. High degree of automation: Enables continuous and automated production. Ring die pellet mills have significant advantages in feed compression, especially for concentrated feed. Their high output and low power consumption make them dominant in large-scale feed processing.
Production range and suitable scale
Ring die pellet mills offer a wide range of production capacities. Small models, such as the SZLH25, have a capacity of 0.5-1.5 tons per hour, suitable for small farms and feed mills with an annual output of 1000-3000 tons; the HKJ-250 has a capacity of 500-700 kg/h. Medium models, such as the SZLH350, have a capacity of 3-6 tons per hour, suitable for small to medium-sized feed mills with a single-shift annual output of 10,000-20,000 tons; the SZLH304 has a capacity of 1-3 tons per hour. Large models, such as the SZLH400, have a capacity of 4-10 tons per hour.
Target customer group
The main customer groups for ring die pellet mills include: production managers and equipment purchasers in feed processing plants; managers of large, medium and small aquaculture farms and livestock and poultry farms; large-scale professional farmers; technicians in bio-organic fertilizer production enterprises; operation managers of biomass fuel pellet production enterprises; and powder processing customers in industries such as grain processing, chemical industry and pharmaceutical industry.
| 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 |
