FLUIDYNE Backpressure Safety Relief or Surplus or Diaphragm Assisted Safety Relief Valve is single seated, diaphragm controlled and spring regulated valve where the pressure of the system being relieved, acting upon the diaphragm provides a sensitive control of the valve opening in accordance with the regulating spring setting. The application or ideal for installations where a direct spring loaded type is too insensitive to pressure or flow changes. The Fluidyne Backpressure Relief Valve Protects systems from overpressure and Monitors pump outputs. Fluidyne Backpressure Relief Valve is most suitable for water, air, gas, steam, oil or chemical services.