roots blower compressor
A Roots blower, also known as a rotary lobe compressor, is a type of positive displacement machine that uses two rotating lobes to compress and move air or gas. It’s a valve-less design where the lobes trap and transfer air between the intake and exhaust ports. Roots blowers are commonly used in low-pressure applications like vacuum pumps and pneumatic conveying systems.
Here’s a more detailed explanation:
How it works:
- Positive Displacement: Roots blowers operate on the principle of positive displacement, meaning they move a fixed volume of air with each rotation of the lobes.
- Counter-rotating Lobes: Two identical, usually symmetrical, lobes (resembling stretched gears) rotate within a housing.
- Trapping Air: As the lobes rotate, they trap air between the lobes and the housing.
- Transferring Air: The trapped air is then carried from the intake side to the exhaust side.
- External Compression: Compression occurs outside the blower as the trapped air is forced against the system’s resistance, such as a pressurized vessel.
Key Features and Applications:
- Valve-less Design:Unlike some other compressor types, Roots blowers don’t require valves for operation, simplifying their design.
- Low Pressure Applications:They are best suited for low-pressure applications, typically under 1 bar (14.5 psi).
- Constant Airflow:Roots blowers provide a relatively constant airflow, making them suitable for applications like pneumatic conveying where steady airflow is important.
- Industrial Uses:They are commonly used in various industries, including food and beverage, chemicals, water treatment, and wastewater treatment.
- Vacuum Pumps:Roots blowers are often used as vacuum pumps to create a vacuum in a system.
- Superchargers:They can also be used as superchargers in internal combustion engines to force more air into the engine, increasing power.
Distinction from Compressors:
- Pressure Ratio:Air compressors typically operate at higher pressure ratios compared to air blowers.
- Compression Method:While both involve compression, compressors often use internal compression (like with pistons or screws), while Roots blowers use external compression.
- Efficiency:Roots blowers generally have lower efficiencies compared to other compressor types, especially at higher pressure ratios.