Ball, Steel, 8 mm diameter, Mirror Finish, Pfeiffer, DUO, Part# 330096

This is a small steel ball. Its part number is 330096. It measures exactly 8 mm in diameter. The surface has a mirror finish, meaning it is extremely smooth and shiny .

This ball is used inside the pump as a check valve. A check valve is like a one-way door. It lets gas flow in one direction. But it blocks gas from flowing back the other way.

This steel ball is made specifically for one pump model:

• Pfeiffer DUO 125 

If you own this pump and are doing a major overhaul or rebuild, you will need this part. In fact, it is included as a standard component in the Major Overhaul Kit (Part # PMK025) for the DUO 125 .

The job of this steel ball is simple but very important.

• Creates a one-way seal: The ball sits in a small cone-shaped seat. When gas tries to flow the wrong way, the ball presses into the seat and blocks it.

• Allows forward flow: When gas flows in the correct direction, it pushes the ball out of the seat. The gas can then pass through.

• Prevents backflow: This keeps the pump working efficiently. Backflow can reduce vacuum pressure and damage the pump over time.