FLD-Argon-Series

Supported Applications

The Omega FLD Series comprises direct read variable area flow meters (rotameters) designed for precise metering of gases and liquids. The series is explicitly documented for use with Air, Water, Nitrogen (N2), Hydrogen (H2), Carbon Dioxide (CO2), Argon (Ar), Helium (He), and Oxygen (O2). 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 flow and level indication.

Operating Conditions & Performance

The FLD Series operates with a maximum operating pressure of 200 psig/13.8 bars and a maximum operating temperature of 121 C (250 F). Standard accuracy is specified as plus/minus 5% of full scale (FS), with repeatability at plus/minus 0.25%. The useful flow range provides a minimum ratio of 10:1, where the minimum flow rate is defined as 10% of the maximum rate shown for each specific model.

For Argon specifically, available ranges include:

• 65 mm tubes (316 SS Frame): Maximum flows from 2.5 scfh to 50 scfh and up to 1000 mL/min.
• 150 mm tubes (316 SS Frame): Maximum flows ranging from 2 L/min to 25 L/min, with specific models covering 33 to 325 mL/min.

Configuration Options

The series offers configurable dimensions and materials tailored to process requirements. Models are available in two tube lengths: 65 mm or 150 mm, housed in either aluminum (black anodized) or 316 stainless steel frames.

Construction Materials

• Flow Tubes: Heavy walled borosilicate glass with rib-guided or fluted designs for stable readings.
• Floats: Options include glass, red sapphire (SA), 316 stainless steel (ST), carboloy (C), and tantalum. The float material is indicated by the model suffix.
• Mounting Fittings: Aluminum (black anodized) or 316 stainless steel for fluid contact areas.
• O-Rings and Packing: Buna O-rings in aluminum/brass models; FKM O-rings in stainless steel meters. Optional perfluoroelastomer and EPR are available.

Housing & Mounting

The standard configuration features side panels of black anodized aluminum, a front shield made of polycarbonate resin with a longitudinal magnifier lens for enhanced reading resolution, and a 1/8 in thick white acrylic back plate. Units are designed for panel mounting (drill two 15 mm holes; maximum panel thickness 9.5 mm) or convertible to bench mounting using optional FLTR-1, FLTR-2, or FLTR-3 acrylic tripods with built-in spirit levelers.

Valve & Connection Options

Inlet and outlet connections are standard at 1/8 NPT female. Built-in control valves include a standard 6-turn needle valve or an optional -HRV suffix for a 16 turn high resolution non-rising stem metering valve (available on 150 mm meters). A no-valve option (-NV) is available by subtracting cost from the base price.

Valve positioning defaults to inlets (bottom); however, for liquids valves may be located at inlets or outlets (top), and for vacuum services valves must be mounted at outlets. An oxygen cleaning option (-02CLEAN) is offered as an additional-cost suffix.

Key Product Differences

The FLD Series distinguishes models by fluid type, tube length, frame material, float composition, and valve configuration. Model numbers follow the pattern FLD[fluid letters][4-digit code][float suffix][options]. For example:

• Fluid Prefixes: FLDA (Air), FLDW (Water), FLDAR (Argon), FLDC (Carbon Dioxide), FLDHE (Helium), FLDH (Hydrogen), FLDN (Nitrogen), and FLDO (Oxygen).
• Tube Length: The third digit in the 4-digit code indicates tube size; '2' denotes 65 mm tubes, while '3', '4', or '5' denote specific configurations for 150 mm tubes depending on fluid and frame.
• Frame Material: Aluminum frames typically use a second digit of '2' (e.g., FLDA32xx), while 316 SS frames often utilize digits like '3', '4', or '5' in the corresponding position depending on fluid and range.
• Float Suffixes: G = glass float; ST = 316SS float; C = carboloy float; SA = red sapphire float. Note that some model numbers carry suffixes like S or T which are not defined in the standard printed legend but appear on specific variants.