Cazuela de Vaca (Beef and Pumpkin Stew) This hearty Chilean stew of beef, corn, and pumpkin is a one dish meal. The main ingredients are stewed in serving-sized pieces, so that each person receives a large piece surrounded by a broth with the other vegetables.
Quick Answer. A rotary vane vacuum pump works by using centrifugal force to turn blades against the circular surface of a cylinder whereby pockets of air are pushed from an inlet port to an outlet port as air pressure increases.
Impellers (and jet-pumps) work on the principal of positive and negative pressure, or the push/pull concept. As a blade rotates, it pushes water back (and outwards due to centrifugal force). At the same time, water must rush in to fill the space left behind the blade.