Combustion Catalog | Fives North American

Product Overview | Limiting Orifice Valve

An 1807 Limiting Orifice Valve is used to set air/gas ratio on a nozzle-mix burner. It has a V-port plug that can be adjusted sensitively and accurately with an Allen wrench. Turning the screw counterclockwise increases flow. A cap conceals the adjustment and discourages tampering with the setting. After adjustment always replace top cap on valve body to reduce air or gas leaks. The V-port adjustment is in a removable gas cartridge assembly, simplifying inspection or replacement. 1807 Valves have brass internals; 1807- -K Valves have iron internals for coke gas and others corrosive to brass; 1807- -TK Valves are for hot gases. Valves with the pre-fix "M" have ISO 7 Rp threaded end connections. 1807- -C valves are cleaned for oxygen service standard. They can be used in applications with system pressure less than 25 psi and pipe velocity less than 100 FPS. For high pressure oxygen valves up to 125 psi see Bulletin 1807B. 1807- -H limiting orfice valves for high pressure service have cast iron bodies, O-ring seals, spring loaded plug for vibration resistance, socket head adjustment, and screw-on cap.

Limiting Orifice Valves are not designed for shutting off gas. Use an approved ball valve, plug valve or cock.

SPECIFICATIONS Operating Pressure: 1807- -C, -K, -TK, 25 psig (1.7 bar) 1807- -H, 125 psig (8.6 bar) Maximum Design Temperature: 1807- -TK, 600°F (316°C) All other 1807's, 225°F (107°C) Minimum Design Temperture: -20°F (-28°C) Body Materials: cast iron Gas Cartridge Assembly Material: 1807- -K SST and Zinc plated steel All other 1807's brass Stuffing Box Cap Material: 1807- -K 303 SST All other 1807's brass O-rings: Viton

TWO TYPICAL PIPING ARRANGEMENTS FOR LIMITING ORIFICE VALVES

SINGLE BURNER

MULTIPLE BURNER

Air

Air

Nozzle Mixing Burner

Nozzle Mixing Burner

Nozzle Mixing Burner

Butterfly Air Valve

Motor Operated Valve

Flexible Nipples 4D min.

1807 Limiting Orifice Valve

1807 Limiting Orifice Valves

10 D min.

Gas

Metering Orifi ce

4D min.

10 D min.

10 D min.

4D min.

Shutoff Valve

Gas/Air Ratio Regulator

Gas

Install 1807 Valve as close as possible to burner. Normal practice is to select limiting orifice valve pipe size same as ratio regulator (North American #7218 or #7216), or as burner gas connection if several burners are fed by one regulator. There is no performance advantage in using the smallest possible 1807 for the flow and pressure drop available.

Bulletin 1807 Page 2

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