Two Ways to Control the Air Quantity of Draught Fan

(1) the working principle of adjusting the air quantity of the draught fan of industrial drying machine: when the draught fan is working in the ventilation network, the actual air volume is equal to the flow of air in the ventilation network and the pressure is equal to the resistance of the ventilation network. The fan performance curve depicts the variation of the air flow and pressure of the fan. The ventilation network characteristic refers to the relationship between the air flow and the resistance of the ventilation network.

When the drying equipment is used to dry the materials, the working conditions of the draught fan need to be adjusted according to production requirements, namely, to change the location of the operating point of the fan to make the output of the air volume keep balance with the actual needs of the air volume. The following is the two ways to control the air quantity.
the throttle regulation: it means that the throttle valve should be installed in the exhaust pipe of the fan in the industrial dryer. According to actual needs, changing the opening degree of the throttle valve will change the characteristics of the pipe to regulate air flow.
(2) the adjustment of the rotational speed: as for the fan itself, it is more economical without additional energy loss when changing the rotational speed of the draught fan. However, it is necessary to use the motor to adjust the speed when changing the fan speed, which will need to add speed control device. In addition, the greater the power of the motor is, the higher the cost will be.