toky electrical co., ltd-九游会登录
add date: 2018-11-21 views: 3265
introduction:
whether it is for daily civilian use or industrial use, heating equipment is essential, and heating equipment plays an important role in all walks of life. large to metallurgical heavy work, small to food heating, will have their own dedicated heating equipment.
figure 1 principle of common heating equipment
at present, in the whole heating industry, the main use of position control mode, pid control mode, manual mode, etc., the most frequently used heating method is pid heating mode, which has the characteristics of intelligent heating and precise heat preservation, realizing full automatic temperature control.
pid control (proportional-integral-derivative control) is a common feedback loop component in industrial control applications, consisting of proportional unit p, integral unit i and differential unit d. the basis of pid control is proportional control; integral control can eliminate steady-state error, but may increase overshoot; differential control can speed up the response of large inertia system and weaken overshoot. by using pid to control heating, it can achieve rapid heating and automatic insulation, which can completely replace the manual operation in the past, and also stabilize the quality of the products produced.
figure 2 pid control effect curve
industry:
food processing equipment
for food processing and food production, baking machines and heating boxes are used. the heating equipment used in today's food production is mainly composed of the following parts: heating box, heating and cooling device, temperature controller and alarm circuit.
this type of control forms the reliability of controlling the closed loop to increase heating. such applications are mainly in the industry where temperature is precisely controlled.
in the baking industry, the temperature requirements are relatively high, because too high and too low will affect the appearance and taste of the product, so accurate temperature control is essential
before using the heating device, you first need to do the self-tuning operation of the device. because the heating controller is shipped from the factory, the relevant coefficient of heating is the factory value, not applicable to all equipment, so the relevant parameters need to be adjusted before heating. this setting process is fully automatic and does not require manual intervention.
take our te-w series temperature control table as an example. after the instrument is installed, press ““at” to start the auto-tuning function under normal temperature and 50% load. wait for 15-30 minutes according to different equipment. after the auto-tuning is completed, enter the menu to see the p, i, and d parameters and make a record.
by using the intelligent pid heating controller, manual field operations can be greatly reduced, and in batch production, products with different batches and different dates can be achieved with high stability.
figure 3 coffee bean roasting equipment
figure 4 puffed food equipment control cabinet
figure 5 large baking equipment
plastic production equipment
temperature control meters are the most widely used in the plastics industry. whether it is raw material processing, preliminary processing, secondary processing, molding processes, etc., temperature control is used, the amount of use is extremely large, and the temperature control has special technical requirements. therefore, the temperature control controller is also required to have precise and stable temperature control.
in the large-scale pc and pvc plastic pipe production plants, the raw materials are initially mixed with heating equipment. in order to ensure the uniformity of the materials during the mixing process and to meet the requirements of the preliminary processing, the temperature of the mixture must be used. control is carried out while the raw material is uniformly heated.
figure 6 raw material mixing unit control cabinet
after mixing, it is the heating before extrusion and the control of different process temperature zones. since the temperature control of the manufacturing process is very precise in the production of plastics, pid temperature control must be used, the equipment starts heating quickly and enters the working state quickly. in order to ensure the requirements of the process, the heating equipment needs precise temperature control and temperature control, so that the entire working area maintains a certain temperature.
figure 7 extruder console
the film production process is similar to that of the extruder. after the preliminary processing of the raw materials, after different process temperatures, high-quality film raw materials are produced, and then the material is stretched and the thickness of the film is controlled.
figure 8 small film machine
figure 9 large film machine
metal production equipment
at present, all metal processing uses heating equipment, steel production, and alloy processing, all of which require heating equipment. however, for the heating equipment generated by metal processing, the position control heating is currently used. due to the large heating power, the final heating equipment needs to use high-power contactors for control, and temperature control in this industry. the requirements are not too harsh, so in order to extend the overall life of the equipment and other comprehensive conditions, the use of position control.
since the requirements for heating and heat preservation are relatively low, it is generally controlled by using an instrument of ai208 or below.
figure 10 large metallurgical equipment
figure 11 large metallurgical equipment control cabinet
small heating equipment
in addition to large heating equipment, of course, small heating equipment, especially experimental testing equipment, small processing, etc., will use heating equipment.
generally, small heating equipment is mainly used in the test industry and small-scale processing, etc., and its temperature control requirements are more demanding. small heating equipment generally uses electric heating, high heating speed, sensitivity, etc., so the stability of heating temperature is high. temperature control instruments of te-w or higher are usually used.
figure 12 experimental heating equipment
figure 13 small steam boiler equipment
figure 14 small sealing machine
to sum up:
by using an intelligent temperature controller, the temperature control effect of the device and the energy consumption of the device can be greatly improved.
the traditional heating method is compared with the pid heating method. the traditional heating method is suitable for occasions with low temperature control requirements. the pid heating method is suitable for occasions with high temperature control requirements; the traditional heating method fluctuates up and down during the heat preservation period. affecting the stability of the product, the pid heating method can achieve a relatively stable heat preservation effect and improve the stability of product production. so now more and more devices will be upgraded to use intelligent temperature controllers.
figure 15 comparison of position control and pid control
