The 50 Series Pressure Relief Valve is designed to maintain constant upstream pressure within close limits. In operation, the valve is actuated by line pressure through a pilot control system, opening fast to maintain steady line pressure but closing gradually to prevent surges. In addition to surge relief, this valve can be used for pressure relief, pressure sustaining, back pressure, or unloading functions in a by-pass system.

There are many variations on the basic pressure relief valve, including but not limited to the following.

• 50-01KO Pressure Relief with KO Anti-Cavitation Trim
• 50-33 Excessive Pressure Safety Shut-Off
• 52 Series Pressure Relief and Surge Anticipator
• 550 Series Pressure Relief, Pressure Sustaining
• 58-01 Combination Back Pressure and Solenoid Shut-Off
• 350 Series Electronic Pressure Relief