Plast-O-Matic Valves” Series TRVDT three-port, in-line relief valve is a good fit for systems requiring minimal footprint or where the use of a piping tee is not practical. The valve has an economical, heavy-duty design and allows for easy replacement in existing systems. When closed, the valve has a straight-through flow pattern. The pressure setpoint is infinitely adjustable between 50 PSI and 100 PSI, with a maximum inlet pressure of 150 PSI. Once the set pressure is reached, the diaphragm is lifted off the center port, and the excess liquid flows out through the third port at the bottom of the valve. The valve features a PTFE diaphragm seal with no wetted metals or elastomers. This diaphragm allows the valve to support highly aggressive, corrosive liquids. The large area of the diaphragm makes for higher sensitivity and a lower pressure drop with high-flow conditions. An additional nonwetted, u-cup seal design includes the patented fail-dry vent, which provides visual warning of impending seal malfunction. This allows the valve to continue operating until maintenance can be performed on the system. Valves are available in pipe sizes of ½”, ¾”, and one inch in PVC, natural polypropylene, PTFE, and Kynar PVDF.