Rosemount 499ACL-01-54 Free Chlorine Sensor
Overview
Rosemount 499ACL-01-54 is a two-electrode, membrane-covered amperometric sensor purpose-built for continuous free chlorine measurement in drinking water and process water applications. Manufactured by Emerson under the Rosemount Analytical brand, the 499ACL-01 uses a silver/silver-chloride anode and a platinum cathode to generate a current directly proportional to the free chlorine concentration present in the sample, eliminating the need for expensive reagents, buffer chemicals, or upstream sample pre-treatment that many colorimetric or DPD-based analyzers require.
As the official authorized partner and exclusive regional representative for Rosemount in Oman and the GCC, Seven Star LLC proudly supplies the 499ACL-01-54 free chlorine sensor to municipal water authorities, desalination plants, and industrial utilities across the Sultanate. Every unit shipped from our Muscat-based inventory is warranted, traceable to Emerson-certified stock, and backed by regional calibration and commissioning support — a level of assurance grey-market resellers cannot match.
Measurement Principle
The 499ACL-01 operates on the amperometric membrane principle. Free chlorine species (hypochlorous acid and hypochlorite ion) diffuse across a selective, gas-permeable membrane cap into an internal electrolyte reservoir, where they are reduced at the platinum cathode. This reduction reaction produces a measurable current in the range of 300 to 700 nA per ppm, which the transmitter linearizes into a 0–10 ppm (mg/L) chlorine reading. Because the membrane physically excludes interfering ions and particulates while allowing only free chlorine species to pass, the sensor delivers accurate readings even in raw or lightly turbid source water.
An automatic pH correction algorithm compensates readings up to at least pH 9.5, removing the need for a separate pH probe or manual buffer dosing in most municipal water treatment scenarios. The sensor also incorporates automatic temperature compensation and automatic pressure equalization across the membrane, which maintains consistent membrane tension and prevents the drift that plagues older amperometric designs. The practical result is a sensor with no moving parts, no reagent consumption, and no scheduled chemical replenishment — only periodic membrane cap renewal, which requires no special tools.
Engineering Design of the Rosemount 499ACL-01-54
The 499ACL-01-54 ships in a rugged polymer sensor body rated for continuous immersion in flowing sample streams up to 50°C and 65 psig, matching the demands of both open-channel and pressurized process piping installations. The membrane cap assembly is field-replaceable and threads directly onto the sensor body without tools, allowing plant technicians to perform routine maintenance in minutes rather than requiring a full sensor exchange or factory service visit.
Electrical connection is made through a shielded, integral cable suited for direct wiring into a Rosemount 1054, 1056, or compatible analyzer/transmitter, which powers the sensor and displays the linearized chlorine concentration. The –54 suffix denotes the standard cable length and connector configuration commonly specified for flow-through assembly mounting in Seven Star LLC’s regional stock, and the sensor is compatible with Rosemount’s flow-through and submersion mounting hardware for straightforward retrofit into existing chlorination monitoring points.
Key Features
The Rosemount 499ACL-01-54 free chlorine sensor combines simplicity, reagent-free operation, and fast response into a single field-proven package:
- Measures free chlorine directly from 0 to 10 ppm without sample pretreatment, reagents, or buffer chemicals.
- Delivers a fast response time of less than 60 seconds, supporting tight closed-loop dosing control.
- Provides automatic pH correction to at least pH 9.5, removing the need for a dedicated pH probe.
- Features an easily replaceable membrane cap that requires no special tools for field service.
- Includes automatic temperature compensation for stable readings across seasonal water temperature swings.
- Maintains correct membrane tension through automatic pressure equalization, extending sensor life.
- Offers an optional Variopol (VP) quick-disconnect connector for sensor replacement without re-running cable.
- Operates reliably in samples up to 50°C and 65 psig for both open-channel and pressurized applications.
Industrial Applications
The 499ACL-01-54 is deployed throughout drinking water treatment plants, wastewater reclamation facilities, and industrial process water systems where continuous, unattended free chlorine monitoring is essential for regulatory compliance and disinfection assurance. Typical installation points include post-chlorination monitoring, distribution network residual verification, cooling tower blowdown monitoring, and RO desalination pretreatment trains where chlorine residual must be tightly controlled ahead of membrane-sensitive processes.
As the officially authorized partner for Rosemount in Oman and the GCC, Seven Star LLC distributes the 499ACL-01-54 to municipal utilities, EPC contractors, and industrial operators throughout Muscat, the Sohar and Salalah economic zones, and the wider Sultanate of Oman. Our regional stock and technical support The Rosemount 499ACL-01-54 reduce lead times for desalination and water treatment projects that cannot tolerate the downtime associated with imported, non-warrantied sensors sourced through unauthorized channels.
Technical Specifications
The table below summarizes the key operating parameters of the Rosemount 499ACL-01-54 free chlorine sensor:
| Parameter | Specification |
|---|---|
| Model | Rosemount 499ACL-01-54 |
| Measured Parameter | Free Chlorine (Cl2) |
| Measurement Range | 0 to 10 ppm (mg/L) |
| Sensitivity | 300 to 700 nA/ppm |
| Response Time | <60 seconds |
| Sensor Type | Two-electrode amperometric, membrane-covered |
| Electrode Materials | Silver/silver-chloride anode, platinum cathode |
| pH Compensation | Automatic to at least pH 9.5 |
| Operating Temperature | Up to 50°C (122°F) |
| Operating Pressure | Up to 65 psig |
| Connector Option | Standard cable or Variopol (VP) quick-disconnect |
| Compatible Transmitters | Rosemount 1054, 1056, and compatible analyzers |
Request a Quote for Rosemount 499ACL-01-54 Free Chlorine Sensor
Seven Star LLC maintains regional warehouse stock of the Rosemount 499ACL-01-54 free chlorine sensor for immediate dispatch across Oman and the GCC. Order the Rosemount 499ACL-01-54 today — contact our instrumentation division for a formal RFQ, a technical datasheet download, or application engineering support for your water treatment or desalination project. As the authorized partner for Rosemount in Oman and the GCC, Seven Star LLC guarantees genuine Emerson stock, full manufacturer warranty, and local calibration support unmatched by unauthorized resellers.
Seven Star LLC recommends the Rosemount 499ACL-01-54 as the standard free chlorine sensor for new potable water and desalination monitoring points across Oman, and keeps the Rosemount 499ACL-01-54 in regional stock for same-week dispatch.
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