The vent and exhaust valve combines functionality with cost-awareness. The valve's function is determined by the replaceable lower valve body.

Functions

Vent and exhaust valves

The ball works like a ball check valve. The control element is a low-density, moving ball. As the liquid rises, the ball floats up, is pressed against the upper valve seat closing automatically. However, as the liquid level drops, gases can flow out past the ball, preventing vacuums and venting the system. This version is often used for storage tanks. The vent and exhaust valve prevents liquid leaks when filling the vessel, but ensures complete filling and does not prevent the vessel being drained.

Exhaust valves

The control element is a moving ball as in a double-seat valve. When open, air can escape. However, as the liquid rises, the ball floats up and is pressed against the upper sealing seat, closing automatically. When the pressure decreases, gravity causes the ball to fall to the lower sealing seat, preventing the liquid column dropping. A typical application is venting pipelines and pump suction lines. That prevents air being sucked in on start-up.