🔍 Key Concepts

• Roots-type blower is a positive displacement air pump, not a compressor in the usual sense • Relationship between rotor speed and volume of air moved per revolution • How the rotors are driven and timed relative to each other

💭 Think About

• Look at the illustration and imagine one full revolution of the rotors: what happens to a single pocket of air from inlet to outlet? Is it squeezed between the rotors, or simply carried around? • Think about how a constant volume per revolution would affect air delivery as engine speed increases or decreases. • Consider how the rotors stay in correct phase with each other. Are they likely to be directly meshed together only, or driven from a common timing gear set?

✅ Before You Answer

• Verify whether compression in a Roots blower occurs inside the casing between rotors, or mainly when air is discharged into the higher-pressure manifold. • Check if air volume per revolution is essentially fixed by rotor geometry, making output depend on speed. • Consider whether "each set of lobes is independently driven" is mechanically realistic for keeping accurate timing/clearance between closely meshing rotors.