FLD-Helium-Series

Supported Applications

The Omega FLD Series comprises direct read variable area flow meters (rotameters) designed for the metering of gases and liquids. The series supports applications including carrier gas metering 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 Helium (He) variants, the broader FLD Series is calibrated for Air, Water, Nitrogen (N2), Hydrogen (H2), Carbon Dioxide (CO2), Argon (Ar), and Oxygen (O2).

Operating Conditions & Performance

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

Configuration Options

The series offers configurable options across frame materials, tube lengths, float types, and valve configurations. Models are available in aluminum frames (black anodized) or 316 stainless steel frames depending on the fluid service requirements.

• Tube Lengths: Available in 65 mm and 150 mm sizes with corresponding flow ranges for Helium from 65 to 120 mL/min (65 mm) and up to 40 L/min or 1500 mL/min (150 mm).
• Float Materials: Floats are available in glass, red sapphire, 316 stainless steel, carboloy, and tantalum. Suffixes denote the float type: G for glass, ST for 316SS, C for carboloy, and SA for red sapphire.
• Valve Options: Standard units include built-in control valves (typically 6-turn needle valves). Optional configurations include a -NV suffix for no valve or an -HRV suffix for a 16 turn high resolution non-rising stem metering valve on 150 mm meters.
• O-Rings and Packing: Aluminum/brass models utilize Buna O-rings, while stainless steel meters use FKM O-rings. Optional perfluoroelastomer and EPR materials are available.

The front shield is constructed of polycarbonate resin with a longitudinal magnifier lens to enhance reading resolution. The back plate consists of 1/8 in thick white acrylics, and side panels are aluminum (black anodized).

Key Product Differences

Variants within the Helium series differ primarily by tube length (65 mm vs. 150 mm), maximum flow capacity, frame material availability, and float composition.

• 65 mm Models: Examples include FLDHE3301S (maximum flow 65 mL/min) and FLDHE3302G (maximum flow 120 mL/min). These are listed with a 316 SS frame.
• 150 mm Models: Examples include FLDHE3501S (1.25 scfh), FLDHE3502C (5 L/min), and FLDHE3504G (100 mL/min). These models offer a wider range of maximum flows, extending to 1500 mL/min.

Mounting is achieved via panel mounting with two retaining nuts supplied; the series supports conversion to bench mounting using optional FLTR-1, FLTR-2, or FLTR-3 acrylic tripods which include a built-in spirit leveler. For vacuum services, valves must be mounted at outlets rather than inlets.