Pilot-operated relief valve for enhanced storage tank reliability and protection

Fisher safety valve portfolio now includes a two-inch model, enabling closer-to-setpoint control, easier installation, and simplified maintenance for smaller tanks

Emerson has introduced the Fisher 63EGLP-16 Pilot Operated Relief Valve for installation on pressurised bullet tanks used to store liquid propane and anhydrous ammonia. This type of pressure relief valve (PRV) is typically installed on tanks fabricated by original equipment manufacturers (OEMs), who provide them to end users, engineering firms or contractor customers. The new valve is certified under UL132 and American Society of Mechanical Engineers (ASME) Section VIII.

With a pre-installed national pipe tapered (NPT) thread standard two-inch male hex nipple, this new product serves the need for a solution with a two-inch connection that provides the same benefit as traditional multi-ported valves, but with simplified installation and maintenance. For this application, the PRV must be connected directly to the tank, with no isolation valve between the tank and the PRV. This National Fire Protection Association (NFPA) 58 code requirement presents challenges when testing the PRV while the tank is pressurised and in operation.

The Fisher 63EGLP-16 Pilot Operated Relief Valve addresses this and other issues because it is the only pilot-operated relief valve on the market designed specifically for this type of service. Operation is implemented with a dual pilot array, providing redundancy, and allowing for removal of one pilot for testing while the other is operational.

Because this is a critical safety-related application, reliable operation over a long lifecycle is needed. This requirement is met by the 2-inch PRV because it is similar in design to the Fisher 63EGLP 4-inch CL300 model, which has been proven in use over the past 10 years.