Inline Flowmeter Measures Chlorine Without the Need for Straight-Pipe Runs

Oct. 6, 2017
Company technicians perform on-site calibration adjustments prior to installation

The Model ST100L air/gas inline thermal mass flowmeter with Vortab flow conditioner from Fluid Components Intl. (FCI) provides accurate flow measurement without the long straight-pipe runs required by other meters.

The successful measurement of chlorine presents a challenge for flowmeter suppliers. Due to safety hazard regulations, flowmeter manufacturers cannot flow chlorine gas at their facilities for calibration. To address this problem, FCI field technicians perform on-site calibration adjustments to match the site-specific installation.

The Model ST100L is an inline, spool piece meter for chlorine measurement, which is available with an optional Vortab flow conditioner. This model is designed for 1-, 1.5- or 2-in. lines (DN25, DN40 or DN50). The conditioner eliminates flow profile disturbances to produce a repeatable flow profile for accurate flow measurement.

The ST100L flowmeter is typically installed in a water disinfection system’s chlorine gas inlet line to the chlorinator panel. For operation in corrosive chlorine gas environments, the meter’s wetted material—including its sensor element, inline flow body, flow conditioner and process connections—are all fabricated of Hastelloy C-276 to ensure their corrosion protection.

ST100L flowmeter users have multiple communication options: 4-20 mA analog, frequency/pulse or certified digital bus communications such as HART, Foundation Fieldbus, Profibus PA or Modbus RS485. Should a water plant’s communication need a change, the ST100L meter can be revised with field or factory replacement of the output circuit board.

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This meter utilizes constant-power thermal mass flow sensing technology that measures flow with 100:1 turndown in ranges from 0.006 to 1,850 scfm (0.01 to 3,140 ncmh). The transmitter/electronics can be mounted with the flow body or may be remotely mounted to 1,000 ft (305 m) away. The transmitter enclosure is NEMA4X/IP67 rated.