FLD-Air-Series

Supported Applications

The Omega FLD Series comprises direct read variable area flow meters (rotameters) designed for the metering of gases and liquids. Documented applications include metering carrier gases in chromatography, indicating and controlling gases in manufacturing processes, liquid and gas measurement in laboratories and pilot plants, as well as general flow and level indicating.

The series supports calibration for Air, Water, Nitrogen (N2), Hydrogen (H2), Carbon dioxide (CO2), Argon (Ar), Helium (He), and Oxygen (O2).

Operating Conditions & Performance

Performance specifications are defined by the specific fluid, tube length, and range selected. The series offers a standard accuracy of plus/minus 5% of full scale (FS) with repeatability of plus/minus 0.25%. A useful flow range of 10:1 minimum is provided, where the minimum flow rate is 10% of the maximum rate shown.

Operating limits include a maximum operating pressure of 200 psig/13.8 bars and a maximum operating temperature of 121 C (250 F). Flow tubes are constructed from heavy walled borosilicate glass, featuring rib-guided or fluted designs for stable readings.

Measurement Ranges by Fluid

The series covers extensive ranges across two tube lengths:

• Air (65 mm tubes): 2.2 scfh to 150 scfh; 0.6 scfm; 1 to 40 L/min; 7 to 1000 mL/min maximum flow.
• Air (150 mm tubes): 2.5 to 94 scfh; 1 to 1.5 scfm; 1.25 to 60 L/min; 25 to 800 mL/min maximum flow.
• Water: 0.5 to 750 mL/min (65 mm); 1 to 500 mL/min, 1.2 to 2 L/min, 3 L/hr, 29 gph, 0.22 to 0.45 gpm (150 mm).
• Argon: 2.5 to 50 scfh, 1000 mL/min (65 mm); 2 to 25 L/min, 33 to 325 mL/min (150 mm).
• Carbon dioxide: 1 to 35 L/min, 20 to 200 mL/min (65 mm); 100 to 300 mL/min, 10 L/min (150 mm).
• Helium: 65 to 120 mL/min (65 mm); 1.25 scfh, 5 to 40 L/min, 100 to 1500 mL/min (150 mm).
• Hydrogen: 1.5 to 42 L/min, 35 to 600 mL/min (65 mm); 225 scfh, 100 mL/min (150 mm).
• Nitrogen: 12 L/min, 6 to 200 mL/min (65 mm); 1.6 scfm, 2 L/min, 100 to 500 mL/min (150 mm).
• Oxygen: 1 to 15 L/min, 50 to 500 mL/min (65 mm); 1 to 58 L/min, 250 to 400 mL/min (150 mm).

Configuration Options

The FLD Series is configurable across frame materials, float types, valve options, and mounting styles. Units are shipped completely assembled with side plates, a protective magnifying front shield, back plate, built-in control valve (standard), and flow tubes.

Construction Materials

• Frame: Aluminum (black anodized) or 316 stainless steel. Side panels are aluminum black anodized; the front shield is polycarbonate resin with a longitudinal magnifier lens; the back plate is 1/8 in thick white acrylics.
• Floats: Glass, red sapphire, 316 stainless steel, carboloy, and tantalum. Suffixes denote material: G (glass), ST (316SS), C (carboloy), SA (red sapphire).
• O-Rings/Packing: Buna O-rings in aluminum/brass models; FKM O-rings in stainless steel meters. Optional perfluoroelastomer and EPR are available.

Valve & Mounting Options

• Standard Valve: Built-in 6-turn needle valve (inlet mounted standard).
• -HRV Suffix: 16 turn high resolution non-rising stem metering valve for 150 mm meters.
• -NV Suffix: Unit without valve.
• Valve Position: Inlets (bottom) standard; for liquids, valves may be at inlets or outlets (top); for vacuum services, valves must be mounted at outlets.
• Mounting: Panel mount with 1/8 NPT female inlet and outlet connections. Convertible to bench mounting using optional FLTR-1 / FLTR-2 / FLTR-3 acrylic tripods with built-in spirit leveler and leveling screws.

Special Service Options

• -02CLEAN Suffix: Oxygen cleaning available (additional cost).
• Fittings: Many fittings of various materials and styles are available for mounting.

Key Product Differences

The series is organized by fluid type, tube length, and frame material. Model numbers follow the pattern FLD[fluid letters][4-digit tube/size/range number][float suffix][options]. Examples include FLDA for Air, FLDW for Water, FLDAR for Argon, FLDC for Carbon Dioxide, FLDHE for Helium, FLDH for Hydrogen, FLDN for Nitrogen, and FLDO for Oxygen.

Tube lengths are available in 65 mm or 150 mm. Frame options include aluminum (black anodized) or 316 stainless steel. Specific model numbers correspond to maximum flow rates defined in the ordering tables; for instance, Air models range from FLDA3201C (2.2 scfh max) to FLDA3434G (800 mL/min max).

Dimensions vary by size: 65 mm units have an inlet/outlet center distance of 114 mm (4.50 in), while 150 mm units measure 224 mm (8.813 in). Panel mounting requires drilling two 15 mm (0.59 in) holes with a maximum panel thickness of 9.5 mm (0.375 in); retaining nuts are supplied.

Approvals include RoHS compliance and a 1 year warranty. NIST traceable calibration is not available for this series.