1. The main part of the oil fume purifier is usually represented by a rectangle or box, which indicates the external shape of the whole equipment.

2. Inside the main body, there will be many components such as motor, fan, filter screen and controller. Among them, the motor and fan are usually represented by a circle or ellipse plus a letter M(Motor). The filter screen is represented by a parallelogram. The controller is represented by a diamond or trapezoid.

3. The power supply of the oil fume purifier is usually represented by a plus sign and a rectangle, indicating the electrical connection between the power supply and the main part.