The performance parameters of the ventilator mainly include flow, pressure, power, efficiency and rotation speed. In addition, the size of noise and vibration is also the main technical indicators of the ventilator. Flow is also known as air volume, expressed as the volume of gas flowing through the ventilator per unit of time. Pressure is also known as wind pressure, refers to the gas pressure increase value in the ventilator, with static pressure, dynamic pressure and full pressure points. Full pressure is equal to the difference between the full airflow pressure at the ventilator outlet section and the inlet section; the static pressure is equal to the difference between the ventilator outlet section and the inlet section; the dynamic pressure is the dynamic pressure of the average airflow velocity at the outlet section of the ventilator. On the same section, the full pressure of the airflow is equal to the sum of the static and dynamic pressure.
There is a certain functional relationship between the flow rate, wind pressure, power and efficiency parameters, and when one of the parameters changes, the other quantities change as well. Draw their relationship into a curve, called a performance curve. The performance curve shape is related to the ventilator type. Changing the air volume and air pressure of the ventilator to meet the requirements of changing operating conditions is called performance adjustment. There are five commonly used regulation methods.① places throttle or valve control flow in the intake or exhaust pipe. This method is the simplest but poorly effective. The ② impeller inlet front placement diversion device changes the airflow direction. The ③ changes the ventilator speed. This method has the best economic performance, but it is more complex. Change the speed should consider the strength of the impeller and the motor load conditions. The ④ changes the impeller width. When the working condition can be changed, the use efficiency of the ventilator does not change much, but it is more complex. The ⑤ changes the mounting angle of the moving blade. Using this method, the equipment cost is the most complicated, but the flow change range is large and the economy is good, generally used for large axial flow ventilator.
