FLD-Oxygen-Series

Supported Applications

The Omega FLD Series comprises direct read variable area flow meters (rotameters) designed for the measurement of gases and liquids. The series is explicitly documented for 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 indication.

While this specific product listing focuses on Oxygen (O2) calibrated models, the FLD Series architecture supports a broader range of media including Air, Water, Nitrogen (N2), Hydrogen (H2), Carbon dioxide (CO2), Argon (Ar), and Helium (He).

Operating Conditions & Performance

The series delivers standard accuracy of plus/minus 5% of full scale (FS) with a repeatability of plus/minus 0.25%. The useful flow range is specified as a minimum ratio of 10:1, where the minimum flow rate represents 10% of the maximum rate shown for each model.

Performance limits are defined by a maximum operating pressure of 200 psig/13.8 bars and a maximum operating temperature of 121 C (250 F). The meters utilize heavy walled borosilicate glass flow tubes with rib-guided or fluted designs to ensure stable readings.

Oxygen Measurement Ranges

Available Oxygen models are configured for two tube lengths, offering the following maximum flow capabilities:

• 65 mm Tube Length (Models FLDO3301G through FLDO3307ST): Maximum flows range from 1 L/min to 8 L/min and 50 mL/min to 500 mL/min.
• 150 mm Tube Length (Models FLDO3501S through FLDO3507S-HRV): Maximum flows range from 1 L/min to 58 L/min and 250 mL/min to 400 mL/min.

Configuration Options

The FLD Series is configurable across frame materials, float types, valve options, and mounting styles. Models are shipped completely assembled with side plates, a protective magnifying front shield made of polycarbonate resin with a longitudinal lens, a back plate, built-in control valves (unless specified otherwise), and flow tubes.

Construction Materials

• Frames: Aluminum (black anodized) or 316 stainless steel. Note that Oxygen models in this listing are supplied with a 316 SS frame.
• Floats: Options include glass, red sapphire, 316 stainless steel, carboloy, and tantalum. Suffixes denote the float material: G (glass), ST (316SS), C (carboloy), SA (red sapphire).
• O-Rings: Buna O-rings are standard in aluminum/brass models; FKM O-rings are used in stainless steel meters. Perfluoroelastomer and EPR options are available.

Valve & Mounting Options

• Standard Valve: Built-in 6-turn needle valve (inlet mounted standard).
• -HRV Suffix: Adds a 16 turn high resolution non-rising stem metering valve, available for 150 mm meters.
• -NV Suffix: Unit supplied without a valve.
• Mechanical Mounting: Designed for panel mounting with two retaining nuts; requires drilling two 15 mm (0.59 in) holes through panels up to 9.5 mm (0.375 in) thick. Bench mounting is achievable using optional FLTR-1, FLTR-2, or FLTR-3 acrylic tripods.

Special Service Options

• -02CLEAN Suffix: Specifies oxygen cleaning for the unit.
• Fittings: Various materials and styles of fittings are available to suit specific installation needs.

Key Product Differences

The primary distinction within this Oxygen series is tube length, which dictates flow range and physical dimensions. The 65 mm models (FLDO33xx) feature a side view of 47 mm open x 29 mm x 16 mm with an inlet/outlet center distance of 114 mm for the smaller size configuration. The 150 mm models (FLDO35xx) accommodate higher flow rates and have an inlet/outlet center distance of 224 mm.

Model numbers follow a structured guide: FLD[fluid letters][tube/size/range number][float suffix][options]. For example, FLDO3301G indicates an Oxygen meter with a 65 mm tube and glass float, while FLDO3507S-HRV denotes a 150 mm unit with a sapphire float and high-resolution valve.

Valve positioning varies by application: standard inlet mounting is used for gases; liquid applications may utilize valves at inlets or outlets (top); vacuum services require valves mounted at the outlet. If unspecified, meters ship with valves at the inlets.