The Roots blower is a commonly used centrifugal positive displacement pressurizer, which can be categorized in the following ways depending on its structure and field of application:

1. Categorized by structure:
   • Single-stage Roots Blower: consists of a pressurized air drum with gas intake and discharge through one inlet and one outlet.
   • Multi-stage Roots Blower: consists of two or more stages of pressurized air drums, each with an inlet and an outlet.
   • Vertical Roots Blowers: Drum wheels are mounted vertically and are typically used in applications with limited space or special needs.
2. Categorized by application area:
   • Industrial Roots Blowers: Used for gas pressurization, ventilation, extraction, discharge and other applications in industrial processes, such as sewage treatment, mine ventilation, water treatment, etc.
   • Environmental Protection Roots Blower: Used for waste gas treatment and purification, including waste water treatment, waste gas desulfurization, waste gas denitrification, etc.
   • Pumped Roots Blowers: With pumping function for applications conveying liquids or high viscosity media, such as chemicals, food processing, paper making, etc.
3. Categorized by pressure:
   • Low Pressure Roots Blowers: For lower pressure requirements, typically operating in the 0.1 to 1.0 atmospheric pressure range.
   • Medium Pressure Roots Blowers: For medium pressure requirements, typically operating in the 1.0 to 3.0 atmospheric pressure range.
   • High Pressure Roots Blowers: For high pressure requirements, typically operating in the 3.0 to 5.0 atmospheric pressure range.

These classifications are only a common way of dividing Roots blowers, and can actually be categorized in more detail based on other parameters and characteristics. The type of Roots Blower best suited for selection will depend on the specific needs and requirements of the application.