Research On The Counter Rotary Fan Anti-surge System Based On PLC And VVVF

The counter rotary fan has two fan of the same model and they are in series with each other, the two impellers rotating in opposite directions are arranged together tightly, the I level impeller airflow convoluted is exactly offsetted by the II level impeller, the counter rotary fan is mainly used in the construction of roads, railways, coal mines and other underground engineering tunnel or the part occasion of the forced ventilation. The paper is brief introduction to vaiahle vaiahle firequency technology at home and abroad, and lists the content and significance of the subject, provides the theoretical and experimental research.The counter rotary fan is a special axial fans that prone to surge easily. The surge is a fan of an unstable running conditions, when the surge happen, the fan noise observably increased, enhanced the body of the fan vibration, and airflow will be a strong pulsing, and the strong pulsing airflow may break the blade, resulting in the serious damage of fan or even endanger the personal safety of staff, so to solve the fan surge is very important and very meaningful. This paper first theoretically analyzed the difference of the speed triangle of the counter rotary fan and the speed triangle of the ordinary fan, and explained fan surge in the mechanism from the micro and macro analysis, raised the possibility of methods solved the surge of the counter rotary fan by the analysis of the speed triangle, and researched to solve the surge of the counter rotary fan by experiments.First, this paper has measured experimental data of a series of fans to run at different frequencies by the manual frequency control experiment, then the managed experimental data using Matlab illustrated to reduce or eliminate surge phenomena is feasible by vaiahle vaiahle firequency technology to the I level impeller, and fully validate the theoretical analysis of this paper. Manual frequency control experiment was a success set the stage for the paper describes the design of an automatic frequency control anti-surge system. This system used modular design, carried out a detailed introduction to the various hardware modules of the system, demarcated the data on the experimental. Automatic frequency control anti-surge system sets the security date and designs a control interface made use of the King View software, and monitors the entire automatic frequency control anti-surge system. When automatic frequency control anti-surge system contained various hardware and software is ready the experiment is begin. The experimental process had been described in detail, and there are some the screenshots about experiment control interface and the experimental results described the experiment of the entire automatic frequency control anti-surge is a success.The effect used vaiahle vaiahle firequency technology to solve the surge of the counter rotary fan is obvious, and the significance of the more significant. Either through the automatic frequency control system to control the running state of the fan, this system can prevent the occurrence of the surge of the counter rotary fan at any time, to avoid accidents caused by the surge of the counter rotary fan. Automatic frequency control anti-surge system circumvents the limitations of the method of ordinary surge and provides a new approach to solve the surge of the counter rotary fan.