Polymetron 8350SC Online pH/ORP Sensor
| Brand | Polymetron |
|---|---|
| Origin | USA |
| Manufacturer Type | Authorized Distributor |
| Origin Category | Imported |
| Model | 8350SC |
| Price | Upon Request |
| pH Measurement Range | 0–14 |
| Accuracy | ±0.05 pH |
| Temperature Compensation Range | up to 110 °C |
Overview
The Polymetron 8350SC Online pH/ORP Sensor is an industrial-grade electrochemical sensing platform engineered for continuous, high-stability measurement of hydrogen ion activity (pH) and oxidation-reduction potential (ORP) in demanding process water applications—particularly in power generation, boiler feedwater, condensate polishing, and demineralized water systems. Built on a robust, field-proven potentiometric principle, the sensor employs a glass pH electrode paired with a reference electrode (Ag/AgCl or calomel, depending on configuration) and a noble-metal ORP element (typically platinum or gold), all housed in a chemically resistant PPS or PVDF body. Its design adheres to fundamental Nernst equation-based response behavior, ensuring traceable, thermodynamically grounded measurements. The 8350SC operates as a two-wire or four-wire analog (4–20 mA) or digital (HART, Modbus RTU) transmitter-integrated probe, enabling direct connection to DCS, PLC, or SCADA systems without intermediate signal conditioning.
Key Features
- Single-platform architecture supporting both pH and ORP measurement modes—reducing spare parts inventory and system configuration complexity.
- Integrated temperature compensation via built-in Pt100 or Pt1000 RTD, validated across 0–110 °C for accurate automatic correction per ISO 7027 and ASTM D1293 conventions.
- Chemically inert wetted materials—including PPS housing, ceramic junction, and low-drift glass membrane—optimized for low-conductivity, high-purity water streams typical in thermal power plants.
- Modular, field-replaceable components: interchangeable electrodes, reference electrolyte cartridges, and cable assemblies minimize downtime during maintenance.
- Intuitive local interface with backlit LCD and tactile navigation buttons; supports guided calibration workflows (1- or 2-point pH, mV offset for ORP) with audit-trail-capable logging when paired with compatible transmitters.
- IP68-rated housing and optional sanitary tri-clamp or NPT threaded process connections for reliable operation in humid, washdown, or pressurized environments.
Sample Compatibility & Compliance
The 8350SC is validated for use in ultra-pure water (UPW), deionized water (DIW), boiler feedwater, turbine condensate, and cooling tower make-up—fluids characterized by low ionic strength (<1 µS/cm), high resistivity (>1 MΩ·cm), and susceptibility to CO₂ ingress. Its asymmetric liquid junction design mitigates junction potential drift under low-conductivity conditions. The sensor complies with IEC 61298-2 (industrial process measurement devices), meets EMC requirements per IEC 61326-1, and supports configuration alignment with FDA 21 CFR Part 11 when integrated with Hach’s SC1000 or GLP-compliant data loggers. Calibration traceability follows NIST-traceable buffer standards (e.g., DIN 19266, ASTM E70), and long-term stability testing confirms ≤0.01 pH/day drift under controlled bench conditions.
Software & Data Management
When connected to Hach’s IntelliCAL™ or SC Series transmitters, the 8350SC enables secure, timestamped data capture with configurable alarm thresholds (high/low pH, ORP deviation, sensor fault), trend history (up to 30 days at 1-min intervals), and export-ready CSV reports. Firmware updates are performed via USB or HART communicator, and configuration parameters—including slope, offset, temperature coefficient, and unit scaling—are stored in non-volatile memory. For enterprise integration, OPC UA and Modbus TCP gateways support seamless ingestion into Historian (e.g., OSIsoft PI, AVEVA System Platform) and LIMS environments, satisfying GMP documentation requirements for critical quality attributes in regulated utilities.
Applications
- Real-time pH monitoring in high-pressure boiler drum water to prevent caustic gouging or acidic corrosion.
- ORP control of sodium hypochlorite dosing in cooling water biocide management.
- Condensate return line surveillance to detect amine degradation or copper/iron oxide carryover.
- Monitoring of mixed-bed polisher effluent to verify resin exhaustion prior to regeneration.
- Feedwater pH optimization in nuclear plant secondary loops per EPRI guidelines and IEEE 381.
FAQ
What is the recommended calibration frequency for the 8350SC in power plant condensate applications?
Calibration should be performed at least once per shift in critical control loops; automated verification using zero-current mV checks can extend intervals between full calibrations where process stability is confirmed.
Can the 8350SC operate reliably below 0.1 µS/cm conductivity?
Yes—its specialized low-conductivity reference system and guarded electrode geometry minimize ground loop errors and junction clogging, enabling stable readings down to 0.05 µS/cm with proper flow cell installation.
Is temperature compensation mandatory for ORP measurements?
While ORP is inherently temperature-dependent, the 8350SC applies only linear mV-to-°C compensation for diagnostic consistency; absolute ORP values are reported at process temperature per ASTM D1498, not corrected to 25 °C.
Does the sensor support predictive diagnostics?
When paired with Hach’s SC200 or SC1000 transmitters, it provides real-time diagnostics including glass impedance, reference junction resistance, and asymmetry potential—enabling proactive maintenance scheduling.
