In final assembly of certain machines/products like cars and refrigerators, fluid systems are filled before the machine/product leaves the manufacturing facility. To speed up the process of filling fluids the air is evacuated from the volume that is to be filled. A second vacuum is required that is applied at the end of the filling process to ensure drip-proof filling and precise measurement of fluids. Large body pumps are usually used to provide speedy evacuation.
Advantages with Piab