Triple Duty Valve

"Triple Duty Valve primarily required on the discharge side of a centrifugal pump in a hydronic heating or cooling system. This valve functions as a shut-off valve, spring loaded silent check valve, and balancing valve. Triple Duty Valves are constructed from rugged cast iron castings that are machined to exacting specifications. These bodies have drilled flanges that are in accordance with ASME B16.1.
The Keckley Style TDV has an automatic and silent operation. The disc will open when the line pressure is approximately  PSI. As the line pressure approaches zero, the spring will close the disc to prevent flow reversal and water hammer. The flow through the valve can be from bubble tight shut-off to full flow by the acme rising stem."