In the pneumatic regulating temperature control device, when the temperature measuring element detects the temperature of each section of the cold feed extruder and converts it into an electrical signal, it is input to the temperature display regulator. All the way to the measurement display part shows the actual temperature, all the way to the adjustment part and compares with the set temperature to get the deviation value, the regulator outputs a signal to control the heating system and cooling system according to certain mathematical rules.
When the measured cylinder temperature deviates from the set temperature value, the pneumatic regulator sends signal commands to control the opening of the pneumatic actuators of the heating system and cooling system according to the magnitude and nature of the deviation. If the barrel temperature exceeds the set value, the opening of the pneumatic actuator of the cooling system increases, and the cooling water flow increases (even to full flow), while reducing the opening of the pneumatic actuator in the heating system Degrees (even fully closed), the temperature of the barrel is reduced to the set temperature value; if the barrel temperature is lower than the temperature set value, the opening of the pneumatic actuator of the cooling water system is reduced to reduce the flow of cooling water ( Even reduced to zero), while increasing the opening of the pneumatic actuator of the heating system, increasing the flow of heating steam (even to full flow), so that the barrel temperature rises to the set value. This cyclical adjustment achieves the purpose of controlling the temperature.
The electric (solenoid valve) adjustment temperature control device is different from the above pneumatic adjustment. The main difference is the on-off electrical signal sent by the temperature regulator, and it often has a proportional nature. When the measured temperature of the barrel is higher than a certain range of the set temperature value, the temperature regulator sends a signal to turn on the power of the electric actuator that controls the cooling water system, and at the same time cuts off the power of the heating system, so that the temperature of the barrel drops; When the temperature drops and is below a certain range of the set temperature, the temperature regulator sends a signal to turn on the power of the heating system, and at the same time cuts off the power of the electric actuator that controls the cooling water system, so that the barrel temperature rises. This repeated heating and cooling makes the temperature value of the system tend to the set value, thereby achieving constant temperature control.
In the early stage of extruder using temperature control device, medium heating and pneumatic adjustment method were often used. At present, electric heating and solenoid valve adjustment methods have basically been adopted to replace traditional methods. The reasons are: ① energy saving; ② simple structure; ③ reliable operation.
The electric heating temperature control device mainly includes an electric heating direct cooling open temperature control device, an electric heating direct cooling closed temperature control device, an electric heating indirect cooling closed temperature control device, and an electric heating direct cooling high temperature closed temperature control device.
Its circulation circuit is composed of circulation pump-body water channel-open water storage (with built-in heater)-filter. A cooling water supply pipe with a solenoid valve is installed on the water reservoir, and an overflow pipe is provided at an appropriate position of the water reservoir. When working, the circulating pump will input the warm water of the water reservoir into the water channel of the fuselage to heat the fuselage at a constant temperature, so that the temperature of the fuselage matches the temperature of the warm water. At this time, the thermocouple on the circulating circuit will detect the temperature of the circulating water and convert it. The electrical signal is input to the controller. If the detected temperature is higher than the set temperature, the controller will turn on the solenoid valve that controls the supplemental cooling water, and at the same time cut off the power supply of the heater, so that the water temperature in the water reservoir drops; if the detected temperature is lower than the set temperature , The controller will close the solenoid valve of the supplementary cooling water pipeline, and at the same time turn on the power supply of the heater, so that the water temperature of the water reservoir is increased, thereby increasing the water temperature of the circulation system. As a result, it is carried out continuously and alternately to achieve constant temperature control of the extruder.
The temperature control machine of the extruder is characterized by simple structure, reliable operation, and low cost. However, the temperature of the circulating water is low, generally below 95°C. It is not suitable for extruders that require higher temperature heating, but it is suitable for general rubber extrusion. The heating temperature of the machine is feasible. Because its circulation loop is open, its water temperature can only be lower than the vaporization temperature of water. If a higher temperature is required, a closed hot water circulation temperature control device must be used. It can increase the pressure of the circulating water and increase the boiling point of the water. The temperature of the circulating water can generally reach 130°C.
Hebei Shuangda Rubber & Plastic Machinery Co., Ltd. is a modern enterprise integrating R&D, production and sales of complete sets of equipment for rubber, silicone and plastic extrusion machinery. Our company is located in Liyuantun Industrial Zone, Wei County, Southeast Hebei Province, with a good geographical location and convenient transportation.
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