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.
To see how the pump works, look at the drawing below. The pump consists of a small diameter pipe (called the piston) inserted into a larger diameter pipe (called the cylinder). The drawing shows the pump at two points during its operation. The top drawing shows air being drawn into the pipe by pulling out the piston. The bottom drawing shows air exiting the pipe when the piston is pushed back in. At the right end of the pipe is a commercially bought one-way valve.