Pietro Fiorentini Aperflux 851 Regulator

The Aperflux 851 is a high-performance downstream gas pressure regulator designed for medium- and high-pressure applications. Self-actuated and pilot-operated, this robust regulator is ideal for use in natural gas distribution networks, as well as civil and industrial installations requiring precision, responsiveness, and safety. Its top-entry design allows for full maintenance without removing it from the pipeline, minimizing downtime and simplifying service.

This model is particularly well-suited for applications with rapid flow changes, such as ON-OFF burners or industrial processes. With a fail-to-open configuration, the Aperflux 851 provides reliable gas flow even in the event of pilot diaphragm failure or loss of sensing pressure.

Key Benefits

• Pilot-operated, self-actuated regulator for accurate downstream pressure control

• Top-entry design allows for easy in-line maintenance

• Fail-open functionality ensures gas flow during pilot circuit failure

• Fast response to operating condition changes, including sudden load variation

• High turn-down ratio with precise pressure regulation

• Compatible with various pilot systems and optional accessories

• ANSI/UNI/DIN flanged connections in sizes 1” to 10”

Technical Highlights

• Max Inlet Pressure: Up to 1,450 PSIG (depending on configuration)

• Outlet Pressure Range: 11.6 – 1,073 PSIG, depending on pilot model

• Min Differential Pressure: Recommended 7.25 PSIG (30 PSIG ideal)

• Temperature Range: -40°F to +140°F with appropriate installation conditions

• Accuracy Class (AC): Up to 1%

• Lock-up Pressure (SG): 2.5%–5% depending on outlet pressure

• Noise Reduction: Optional DB/851 silencer reduces sound at the point of throttling

• Slam-Shut Devices: Available models SB/82 and HB/97 for over/under-pressure protection

• Integrated Monitor: Optional PM/819 safety monitor ensures continuity if the main regulator fails
   

Common Applications

• Natural gas gate stations

• Industrial gas delivery systems

• Civil gas distribution networks

• Burner systems requiring fast pressure response
   

Optional Accessories

• Slam shut valves (OPSO/UPSO)

• In-line safety monitor