Serie 3800
24Pages

494C Pilot Operated Pressure Relief Valves Series 3800 Pilot Operated Pressure Relief Valves

Principles of Operation Closed Valve Position: as the system approaches set pressure, the pressure pick-up transmits the pressure from the inlet of the main valve through the pilot control and into the dome of the main valve. This pressure acts upon the top of the piston in the dome, holding the piston rmly against the seat on the nozzle in the main valve. The surface area of the piston in the dome of the main valve is greater than the seat area, so the greater the system pressure, the greater the force holding the piston on the main valve seat. As a result, the pilot operated relief valve...

Main Valve: Advantage Farris Convertible Design: the unique convertible design mini- Main Valve Soft Seat: unlike metal seated valves which mizes the number of components and maximizes their interchangeability, reducing parts inventories and overall costs. require costly machining and lapping procedures, the main valve soft seat is easily maintained and repaired. Convertible Nozzle: threaded convertible nozzles can be Less Weight, Lower Prole: system pressure provides removed and replaced easily without factory service. They can be installed with common tools while the valve is in line,...

Series 3800 Main Valve General Notes: 1. Part used on 3" inlet sizes and larger. 2. Materials certified in compliance with NACE hardness requirements. 3. Teflon for seals required in main valve for temperatures below -20°F. Consult the Factory. 4. Teflon used for 0-Fiing Seat Seal (Item 12) for all valves with 900#, 1500#, and 2500# inlet flanges. Inconel is a registered trademark of Inco Alloys International, Inc.

PCF3, HPCF3 & PCL Pilot Control Valves: Advantage Farris \£Crt/U*> pilot control valves are snap acting and non-flowing, minimiz- ing the flow of line media through the pilot for reduced fugitive emissions and extended valve life. Full 316 Stainless Steel Construction: resists corro sion and extends the life and versatility of the PCF3, HPCF3 Adjustable Blowdown: allows setting blowdown between 3% and 7% of set pressure so that product loss is minimized and fugitive emissions reduced. Viton Seats and Seals: these corrosion-resistant seals and seats enhance valve life. Neoprene, ethylene...

Series 3800 Pilot Control Valve General Notes: 1. For NACE Service (S7 Trim), substitute ethylene propylene.

Selection Table:

Selection Table: General Notes: 1. Standard elastomer is Viton which is suitable to a maximum temperature of 450°F. For temperatures above 450°F, the O-Ring Seals must be specified as Kalrez®. Consult the Factory. 2. The 300# and 600# flanges have identical drilling with flange thickness equal to the 600# class. 3. For liquid service applications, add "L" to the type number for valves with standard size connections and "Y" for valves with oversize connections. Example: 38FC10L-120 and 38FC10Y-120. 4. Valves with ring joint inlet connections available on application only. Consult the Factory.

Selection Table: Full Port Design Selection Table: Dual Port Design General Notes. Standard elastomer is Viton which is suitable to a maximum tempera- ture of 450°F. For temperatures above 450°F, the O-Ring Seals must be specified as Kalrez. Consult the Factory. The 300# and 600# flanges have identical drilling with flange thickness equal to the 600# class. Full port design suitable for use on air, gas, and vapor services only. A 1" X 2" valve is available with an "A" orifice (0.719 sq. in.) provided remote sensing is specified. Valves with ring joint inlet connections available on...

Numbering System Orifice Area Temperatures & Materials Orifice Area Orifice Area Elastomer O-Ring Seat Seal Teflon O-Ring* Seat & Seals (Main Valve Only) To simplify the selection and specifying of Farris pressure relief valves, use the following type numbering system. The type number- ing system is ideal as the digits which comprise a specific type number have a distinct significance. The digits describe the basic valve series, orifice, seat and internal construction, inlet temperature range, body, and spring material, inlet flange class as well as Code liquid design. Ordering Information...

Inlet Class Inlet Facing Raised Face, Ring Joint inlet facing only, also used: L-Liquid Service Vapor Service Y-Liquid Service D-Air & Vapor E-Liquid Service valves only. Parts Replacement Valves: If an exact replacement valve is required, the valve type, size and serial number must be specified to assure proper dimensions and material being supplied. If a specific valve has become obsolete, a recommendation for the current equivalent, Spare Parts: When ordering parts, use part names as listed in the bills of material in this catalog. Specify valve type, size and serial number. If serial...

Sizing Information The 3800 Series pilot operated valves are built in conformance to Section VIII of the ASME Boiler and Pressure Vessel Code for air, gas, vapor and liquid services. Sizing is per the equations listed below. For Air, Gas & Vapor Service: (SCFM) For Vapor or Gas Service: (Lbs./hr.) A = Required orifice area in square inches V = Required gas capacity in SCFM W = Required vapor capacity in pounds per hour VL = Required liquid capacity in U.S. gallons per minute P = Relieving pressure in pounds per square inch absolute = set pressure + overpressure + 14.7 psig where the...

Accessories A full line of accessories is available to meet your service requirements. Manual or Remote Blowdown PILOT CONTROL CHECK VALVE FOR MANUAL BLOWDOWN VALVE REMOTE CONTROL ONLY (OPEN TO DEPRESSURE) Manual or Remote Blowdown: the main valve can be cycled to the open position by venting the pressure in the dome above the piston. The optional manual valve for this purpose mounts directly on the main valve. By installing a solenoid valve, the main valve can be cycled remotely. Neither the manual or remote blowdown system will interfere with the normal overpressure protection provided by...