Rotary pump has two subtypes: rotary gear and which?

• A. Rotary vane
• B. Piston
• C. Gear
• D. Diaphragm

Answer: (A)

Rotary pumps are positive-displacement devices driven by a rotating element that traps fluid in small chambers and moves it to the discharge. Among the rotary family, the two common subtypes are gear pumps and vane pumps. The vane pump uses a rotor with sliding vanes that sweep fluid into and out of expanding and contracting pockets as the rotor spins, creating a steady flow with each revolution. This is the other subtype complementary to gear pumps, which rely on intermeshing gears to form sealed chambers. Piston and diaphragm pumps, by contrast, operate with reciprocating motion or a flexible membrane and aren’t considered rotary subtypes. So the correct pairing for the two rotary subtypes is gear and vane.