🔍 Key Concepts

• How a positive displacement rotary (Roots-type) blower actually moves air (does it squeeze it smaller, or just carry it along at nearly constant volume?) • Difference between internal compression (inside the casing between lobes) and external or backflow compression (when air meets a higher-pressure space at the outlet) • What happens to the air pocket when it first opens to the discharge passage/manifold which is already at a higher pressure

💭 Think About

• Look at the spaces numbered around the lobes: do those pockets get smaller in volume as the lobes rotate, or do they stay nearly the same size while moving from inlet to outlet? • If the pockets don’t really shrink, then where could the pressure rise actually occur—while trapped between lobes, while sliding along the casing, or when that trapped volume suddenly connects with the high‑pressure discharge area? • Think about how the discharge manifold pressure is maintained: does the blower itself squeeze the air to that pressure before it leaves, or does the pressure jump happen as the fresh air mixes with air already at higher pressure at the outlet?

✅ Before You Answer

• Verify whether any part of the casing and rotor motion actually reduces the trapped volume of the air pocket (true compression) • Identify exactly where the trapped air pocket first opens to a region of higher pressure in the drawing • Confirm whether this blower is mainly a moving device (air transporter) or a true internal compressor that squeezes the air between lobes or between lobes and casing