Research On Composite Heat Tracing Antifreeze Technology For Instruments In Cold Areas

Whenever the winter comes,there will often be problems of instrument freezing or malfunction in some areas with low temperature.Serious accidents may cause accidents such as poisoning,fire and explosion,which will cause a great potential safety hazard for instrument and equipment in industrial production.The existing instrument antifreeze measures have different degrees of malpractice.Therefore,for some large instrument users,the winter meter antifreeze is a difficult task.In view of the above problems,this paper has studied a kind of compound thermal antifreeze technology in cold area.This way of heating can not only keep the instrument in the instrument box hot,but also control the temperature inside the instrument box,so as to ensure the normal work of the instrument.The research work of this paper mainly includes:1.Firstly,the background of the research and existing heat tracing measures was investigated.Based on the analysis and summary of the existing heat tracing measures,the exploration and research of the instrument composite heat tracing and freezing protection technology is carried out in the cold area.Based on the basic theory of heat transfer,the principle of steam tracing and electric heat tracing is used to analyze the principle of compound heat tracing.The equivalent circuit of the electric tracing unit is established and analyzed.Based on the above analysis and research,a transfer function model of the compound tracing system is established,which provides a theoretical basis for further research work.2.The temperature field of single steam pipe and double steam pipe in different locations of the instrument box is simulated by ANSYS.Then the temperature field of the compound heat tracing in the instrument box is simulated through the replacement of the electric heating sheet.At the same time,the optimal distribution position of the steam combined tube and electric heating plate was analyzed and optimized.3.A single-chip microcomputer is used as the core control unit,and the hardware and software control system of the compound heat tracing is designed,so that the temperature in the instrument box can be effectively controlled.4.In order to control the temperature of the instrument box effectively,the temperature switch control algorithm and the PID parameter self-tuning control algorithm based on the relay feedback are studied,and the simulation evaluation and experimental verification of the PID parameter self-tuning control algorithm based on the relay feedback are carried out.The results show that the temperature fluctuation of the temperature switch control algorithm is large,and it is suitable for application in the situation of low temperature control precision,while the temperature control effect of PID parameter self-tuning control algorithm based on relay feedback is better,the temperature fluctuation after adjustment is small and the steady-state error is small,it is the application of compound heat tracing system.The best temperature control algorithm.5.The production and debugging of the compound thermal antifreeze experimental device have been completed.A comparison test of heat tracing effect between heat tracing and compound tracing is carried out,and the temperature control algorithm in the instrument box is tested and analyzed.The test results show that the compound heat tracing has obvious advantages over the single way in the economy,controllability and stability,and the temperature control effect of PID parameter self tuning control algorithm based on relay feedback is more precise and stable than the temperature switch control algorithm.The instrument composite heat tracing and anti freezing technology in cold area has the advantages of low cost,high stability and high accuracy in temperature control.It has great practical value in the process of instrument antifreeze And a utility model patent has been authorized.