Pilot Operated Pressure/Vacuum Relief Valve

Groth Corporation660 Pilot Operated Pressure/Vacuum Relief Valve are used on liquid storage tanks and other process vessels or systems to prevent structural damage due to excess internal pressure or vacuum. Storage tanks are pressurized when liquid is pumped in and compresses the existing vapor or when increasing temperature causes increased evaporation or expansion of existing vapor. Conversely, vacuum may be created when pumping out or decreasing temperature. To prevent damage, vapor must be allowed to escape or enter the tank at a specified pressure or vacuum. The volume rate of venting depends upon the tank size, volatility of the contents, the pumping rate and the temperature. See API Standard 2000 for the procedures to determine venting requirements.

The pilot operated relief valve has two principal advantages over other types of relief valve. First, it is bubble tight to set pressure, and second, it is fully open at less than 10% above set pressure. These characteristics permit an operating pressure nearer to the maximum allowable working pressure of the tank. Higher operating pressures reduce evaporation and total venting volume, thereby reducing product loss and cost of processing emissions. A tank may also have provisions for emergency pressure relief due to fire exposure and/or inert gas blanket in the vapor space.

Features:

• Sizes 2 in.-12 in.
• Settings from 2 in. W.C. to 15 psig
• Standard body materials are aluminum (type 356), carbon steel or 316 SS
• Temperature range from -323°F-+300°F
• Cryogenic service
• Provides ability to meet Clean Air Act requirements
• Premium seat tightness to set pressure
• Snap or modulating valve action
• Designed for easy maintenance
• Inherent backflow prevention
• ISO 9001 certified manufacturing process
• Easily adjustable blowdown

<%=company%> 1202 Hahlo St., P.O. Box 15293, Houston, TX 77220-5293. Tel: 713-675-6151; Fax: 713-675-3714.