Fan is used to transport gas. From the energy point of view, it is a kind of machinery which transforms mechanical energy of original motor into gas energy. It is divided into centrifugal fan, axial flow fan, diagonal flow fan, centrifugal fan, axial flow fan, diagonal flow fan and cross flow fan, boiler fan, ventilation fan, industrial furnace (cupola, forge furnace, metallurgical furnace, etc.) Fan, mine fan, main fan (also known as main fan), local fan (also known as local fan), pulverized coal fan.
Current situation of fan: according to the general provisions of fan design specification, the air volume margin of forced draft fan and induced draft fan is 5% – 15%, and the wind pressure margin is 10% – 20%. In the design process, it is difficult to calculate the resistance of the pipe network and to consider various problems in the long-term operation process. Usually, the maximum air volume and wind pressure margin of the system are always taken as the basis for type selection. However, the model and series of fans are limited. It is often to lean upward when the appropriate fan type number is not selected. It is common for the margin to be greater than 20-30%. Therefore, when these fans operate, only by adjusting the opening of air door or air duct baffle to meet the requirements of production process for air volume. The mechanical characteristic of fan is square torque characteristic. When the fan is running, the method of adjusting the opening of damper or duct baffle to adjust the air volume of fan is called throttling regulation. In the process of throttling regulation, the inherent characteristics of the fan remain unchanged. Only by closing the opening of the damper or baffle, the resistance of the pipeline will be increased artificially, thus increasing the loss of the pipeline system, which is not conducive to the energy-saving operation of the fan. Generally, the air volume is controlled by the regulating valve. Although the control is simple, the power consumption is large, which is not conducive to energy saving. It is a simple control mode in exchange for high operating cost.
According to the variable torque characteristics of the fan, the inverter can calculate and output the actual active power at high speed, realize the special automatic energy-saving operation, and achieve good energy-saving effect; because the inverter adopts the AC-DC-AC inverter working characteristics, the motor has the soft start and soft stop function when starting or stopping, which reduces the impact on the grid when the motor starts, and improves the equipment At the same time, because of the strong protection function of frequency converter, it plays a very good role in protecting the equipment and effectively reduces the maintenance cost of the equipment.
After the transformation, the sudden change of load will not cause trip and other accidents; at the same time, the frequency converter has a variety of protection functions, which can calculate and protect over-voltage, under voltage, over-current, overload and overheating in the frequency converter, and record the cause of the fault, which is of the most practical significance. The compressor working condition supplied according to the gas demand is economic operation In line state, under normal operation of equipment, it can save 10% to 75% in general (non critical load operation).