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.
Since no centrifugal force exists until the motor begins to rotate, something, usually springs, must be used to initially hold the vanes against the casing contour. However, springs usually are not necessary in vane-type pumps because a drive shaft initially supplies centrifugal force to ensure vane-to-casing contact.