Double-rotor continuous mixer structure
Double-rotor continuous mixer is a new type of rubber and plastic continuous mixing machine, which can work continuously and maintain the superior mixing characteristics of the mixer. It looks like a twin-screw extruder, but the way of feeding and discharging is different from that of a twin-screw extruder.
The machine is mainly composed of barrel, rotor and discharging device. The mixing chamber of the equipment cylinder is two interconnected holes with a cross section of ∞. The rotor in the mixing chamber shears, crushes, kneads and mixes the materials. The cylinder is also provided with cooling water holes and electric heaters, which can heat and cool the materials according to the process requirements.
Rotor structure can be divided into feeding section, mixing section and discharging section according to function.
The feeding section of the rotor is like a pair of non-meshing twin screws, and its surface is composed of rectangular threads, which convey the materials added by the metering feeder to the mixing section. The mixing section of the rotor is like a pair of rotors in an internal mixer, and there are two pairs of spiral ribs with opposite directions and different angles on its surface. The spiral rib connected with the feeding section conveys the material forward, and the spiral rib connected with the discharging section conveys the material in the opposite direction, where the material is compressed, melted, cut, stretched and finally mixed and plasticized; The discharge part of the rotor is oval, and the material is discharged from the barrel through the discharge port. The discharging device consists of a discharging door and an adjusting device. By adjusting the discharge adjusting device, the opening of the discharge door can be controlled, so as to control the residence time of materials in the mixing cavity.
Working process of double-rotor continuous mixer
Various polymer materials are added to the continuous mixer through a quantitative feeder and sent to the mixing section through the threads of the rotor feeding section. In the mixing section of the rotor, the material is first pushed forward by the connecting part of the screw and the feeding section, while the connecting part of the screw and the discharging section forces the material to move in the opposite direction. In this way, materials are piled up here, cut, crushed, crushed, melted and mixed. With the continuous addition of new materials, the mixed materials are finally forced to move to the discharge section and discharged through the discharge door.
Because the discharging capacity of the continuous mixer is determined by the feeding capacity, the equipment can work in the hungry state or in the full state. Therefore, the residence time and output of materials in the mixer can be adjusted by controlling the feed rate. The adjustable working parameters of the machine are: feed speed, rotor speed, back pressure, temperature, discharge port, etc. The experiment shows that the discharge temperature increases with the increase of rotor speed and decreases with the increase of discharge door opening. The input power increases with the increase of output (feed rate) and rotor speed, and decreases with the increase of discharge door opening and barrel temperature.
In the working process of double-rotor continuous mixer, the mixing effect of materials mainly occurs in the mixing section of rotors. Because the length, helix angle and rotation direction of the eight spiral ribs on the mixing section of the two rotors are different, the material will be pushed by the eight spiral ribs with different sizes and directions in turn. Therefore, the moving speed and direction of the melt will change at least eight times in a circulating flow process. Usually, in the process of mixing, the speed and direction of material flow will change about 5000 times in a mixing section. This change further aggravates the renewal of material mixing interface and the disorder of flow, promotes the breaking and dispersion of dispersed phase and the formation of new phase interface, which is extremely beneficial to the dispersion and mixing of materials and the elimination of low melting point volatiles, and makes the machine have good dispersion and mixing characteristics and degassing performance.
Characteristics of double-rotor continuous mixing granulation unit
We combine a double-rotor continuous mixer and a hot-feed single-screw extruder into a set of double-rotor continuous mixing and granulating unit with continuous mixing and extrusion functions. Compared with the traditional mixing equipment, this equipment has the following characteristics:
Reasonable structural design
Adopting the latest mixing theory, the computer newly designed double mixing section structure, wedge-shaped high-efficiency rotor configuration (national invention patent), high shear rate, good dispersion filling mixing effect and large production capacity.
A variety of rotor structure configurations can meet various mixing process requirements of different materials;
Split barrel, convenient and quick to clean materials;
The two-step arrangement separates the mixing function from the extrusion function of the machine, which has wide technological adaptability and excellent filling, dispersing and mixing capabilities.
The unique design of electric heating and closed-loop constant temperature soft water cooling system makes the temperature adjustment and control of each section more flexible and effective, and can cool the mixer rotor and extruder screw core respectively.
There are many controllable variables and good universality.
During the working process of the mixer, the mixing process is adjusted and controlled online by adjusting the operating parameters such as feed speed, rotor speed, barrel temperature and discharge port, so as to achieve the expected mixing effect without stopping.
Convenient maintenance
No complicated thrust bearing system, simple and convenient operation and maintenance; Low energy consumption and operating cost (under the same process conditions, the energy consumption per unit product is 30~50% lower than that of conventional equipment). The barrel is of split structure, so the material cleaning is convenient and thorough; The rotor adopts double mixing section structure, so it is not necessary to disassemble the bearing when disassembling the rotor, and the maintenance is quick and simple.
Highly automated
The whole system adopts advanced PCC centralized control, which can make the mixing operation process of the equipment always in the best state; Perfect interlocking control ensures automation, high efficiency, safe production and stable product quality.
The real-time operation of the process monitoring and recording system realizes the real-time recording, display and remote transmission of operation parameters, which provides a strong guarantee for stable production and product quality control.
The mixed element has good wear resistance.
The mixing cavity of the barrel adopts imported cemented carbide S600 sleeve, the rotor adopts high-quality nitrided steel, and the surface is covered with cemented carbide, which solves the problem of equipment wear.
There are various granulation methods, which can meet different technological requirements.
The granulation of this unit can be matched with traction granulation equipment, underwater granulation equipment and air-cooled hot-cutting granulation equipment according to different mixed materials.
Low labor intensity and good environmental protection.
Weightless metering feeding is recommended for the equipment, and pretreatment by high-speed mixer is not needed. Workers have low labor intensity and a good environment.