Hach 8315 / 8316 / 8317 Contact Conductivity Sensors

Overview

The Hach 8315, 8316, and 8317 contact conductivity sensors are precision-engineered electrochemical transducers designed for continuous, real-time measurement of aqueous solution conductivity in demanding industrial water quality monitoring applications—particularly in power generation, pharmaceutical water systems, boiler feedwater control, and high-purity process streams. These sensors operate on the two-electrode or four-electrode contact principle, where an alternating current is applied across inert stainless-steel electrodes, and the resulting voltage drop is measured to determine solution conductance. The electrode geometry, cell constant calibration, and temperature compensation algorithm (based on Pt1000 or built-in thermistor) ensure stable, drift-resistant performance across wide dynamic ranges—from ultrapure water (0.057 µS/cm) to concentrated brines (20,000 µS/cm). Unlike non-contact (inductive) sensors, contact-type designs offer superior resolution and accuracy at low conductivity levels, making them essential for condensate polishing, demineralizer effluent monitoring, and steam cycle chemistry control in thermal power plants.

Key Features

• Robust 316 stainless steel sensor body and electrode assembly engineered for long-term stability in aggressive chemical environments and high-pressure/temperature process lines.
• Three model variants (8315, 8316, 8317) differentiated by cell constant (K = 0.1 cm⁻¹, 1.0 cm⁻¹, and 10 cm⁻¹), enabling optimal sensitivity and linearity across distinct conductivity regimes.
• Interchangeable mechanical and electrical interfaces—compatible with Hach SC1000, SC200, and CL17sc controllers—supporting seamless integration into existing Hach ecosystem architectures.
• Factory-calibrated with NIST-traceable standards; optional field recalibration using certified KCl solutions (e.g., 0.01 M, 0.1 M) per ASTM D1125 protocols.
• Integrated temperature sensing (Pt1000 or thermistor) enables automatic temperature compensation to 25 °C using the classic linear or nonlinear (non-linear β-factor) algorithms per ISO 7888.
• IP68-rated housing ensures reliable operation under submerged or washdown conditions; suitable for inline, insertion, or submersible mounting configurations.

Sample Compatibility & Compliance

These sensors are validated for use in deionized water, reverse osmosis permeate, condensate, cooling tower makeup, wastewater effluent, and saline process streams. They comply with international standard methods for conductivity measurement—including ISO 7888 (Water quality — Determination of electrical conductivity) and ASTM D1125 (Standard Test Methods for Electrical Conductivity of Water). When deployed within a validated Hach SC-series controller platform, the full system supports data integrity requirements aligned with FDA 21 CFR Part 11 (electronic records/signatures), GLP, and GMP documentation workflows—including audit trail logging, user access controls, and calibration event archiving.

Software & Data Management

Data output is supported via isolated 4–20 mA analog signal (HART-enabled on select models) or digital Modbus RTU/ASCII over RS-485. When connected to Hach’s SC1000 or SC200 controllers, users gain access to embedded configuration tools, real-time diagnostics (e.g., electrode fouling detection, cable integrity check), and automated calibration prompts. Hach Insight™ software (Windows-based) enables centralized fleet management, historical trend analysis, alarm threshold configuration, and export of time-stamped CSV reports compliant with laboratory information management system (LIMS) ingestion protocols. All controller firmware updates and calibration certificates are traceable through Hach’s secure customer portal.

Applications

• Power plant cycle chemistry monitoring: condensate, feedwater, and blowdown conductivity surveillance per EPRI guidelines.
• Pharmaceutical purified water (PW) and water-for-injection (WFI) systems—meeting USP and EU Annex 1 requirements for conductivity verification.
• Industrial boiler water treatment control and ion exchange resin exhaustion detection.
• Municipal and industrial wastewater treatment—effluent compliance reporting under NPDES permits.
• Chemical manufacturing process stream purity verification and rinse water monitoring.

FAQ

What is the difference between the 8315, 8316, and 8317 models?

The distinction lies in their cell constants: 8315 (K = 0.1 cm⁻¹) is optimized for ultrapure water (0.057–200 µS/cm); 8316 (K = 1.0 cm⁻¹) covers general-purpose range (1–2,000 µS/cm); 8317 (K = 10 cm⁻¹) is intended for high-conductivity applications such as seawater or brine (100–20,000 µS/cm).
Can these sensors be used in pressurized piping systems?

Yes—rated for continuous operation up to 10 bar (145 psi) at 80 °C when installed with appropriate compression fittings or sanitary clamps.
Is temperature compensation mandatory?

Yes—conductivity is inherently temperature-dependent. All three models include integrated temperature sensing and apply automatic compensation per ISO 7888 Annex B algorithms.
How often should calibration be performed?

Initial factory calibration is valid for 12 months under normal operating conditions. Field verification is recommended quarterly; recalibration frequency depends on application severity, fouling risk, and regulatory requirements (e.g., daily verification in GMP water systems).
Are replacement electrodes or service kits available?

Electrodes are not user-replaceable; the entire sensor assembly is serviced as a unit. Hach offers extended warranty and certified refurbishment programs through authorized service centers.