HACH 1720E Low-Range Online Turbidimeter
| Brand | HACH |
|---|---|
| Origin | Imported |
| Manufacturer Type | Manufacturer |
| Model | 1720E |
| Configuration | Online |
| Measurement Range | 0.0001–9.9999 NTU and 10.000–99.999 NTU (auto-ranging) |
| Resolution | 0.0001 NTU (0–9.9999 NTU) |
| Operating Temperature | 0–50°C (single-sensor), 0–40°C (dual-sensor) |
| Accuracy | ±2% of reading or ±0.015 NTU (whichever is greater) for 0–10 NTU |
Overview
The HACH 1720E Low-Range Online Turbidimeter is an EPA-compliant, continuous-monitoring instrument engineered for high-precision turbidity measurement in low-concentration aqueous streams. It operates on the principle of 90° side-scatter detection using a tungsten-filament incandescent light source and a submerged photodetector—fully compliant with Standard Method 2130B and USEPA Method 180.1. The optical architecture is optimized for stability in sub-1 NTU applications, where sensitivity to air entrainment, flow pulsation, and refractive index variation poses critical challenges. A proprietary bubble elimination system actively removes entrained air from the sample stream prior to optical interrogation, decoupling measurement integrity from hydraulic fluctuations—ensuring consistent performance across variable pressure and flow conditions typical in municipal filtration and membrane process monitoring.
Key Features
- Auto-ranging dual-scale measurement capability (0.0001–9.9999 NTU and 10.000–99.999 NTU) with seamless transition between ranges
- Integrated bubble removal module eliminating interference from microbubbles—a dominant error source in sub-0.1 NTU measurements
- EPA-certified 90° scattered-light detection geometry with temperature-compensated photodiode and stable tungsten lamp source
- Flexible calibration protocol: supports two-point calibration (0 NTU and 20 NTU standard) or single-point verification across 1–40 NTU range
- Multi-unit display output: NTU (nephelometric turbidity units), FTU (formazin turbidity units), TE/F (turbidity equivalent/formazin), and mg/L (as formazin equivalent)
- Robust stainless-steel sensor housing rated for continuous immersion; IP68-rated electronics enclosure
- Low maintenance design: calibration interval recommended every 90 days under normal operating conditions
Sample Compatibility & Compliance
The 1720E is validated for use with potable water, filtered surface water, membrane permeate, activated carbon effluent, and recirculating cooling water—applications requiring trace-level particulate quantification. Its optical path geometry and signal processing algorithm are optimized for samples with low-to-moderate particle density and minimal color interference. The instrument meets ISO 7027:2016 requirements for nephelometric turbidity measurement and is referenced in ASTM D6508 and USP . For regulated environments, its analog/digital outputs support integration into SCADA systems compliant with ISA-88/ISA-95 frameworks, and audit-trail-capable data logging satisfies GLP and GMP documentation requirements per FDA 21 CFR Part 11 when paired with HACH’s DataStream software.
Software & Data Management
The 1720E interfaces seamlessly with HACH’s PlantWeb® digital ecosystem via 4–20 mA analog output, Modbus RTU/ASCII, or optional Ethernet/IP. When connected to HACH’s DataStream™ software (v5.0+), it enables time-stamped trend visualization, automated calibration logging, alarm threshold configuration (e.g., deviation >0.02 NTU from baseline), and export of CSV/Excel-compatible datasets. All calibration events—including date, operator ID, standard lot number, and measured deviation—are stored with immutable timestamps. Firmware updates are performed via secure USB or network-based OTA protocols, maintaining version traceability per IEC 62443-3-3 cybersecurity guidelines.
Applications
- Drinking water treatment: real-time monitoring of filter effluent, sedimentation basin outflow, and finished water distribution points
- Municipal distribution networks: early detection of main breaks or biofilm sloughing through turbidity excursions ≥0.05 NTU
- Membrane filtration plants: integrity verification of UF/MF membranes by detecting sub-0.1 NTU breakthrough events
- Pharmaceutical water systems: compliance with EP 2.2.2 and JP 2.05 for purified water and water-for-injection (WFI) quality assurance
- Power generation: monitoring of condensate polishing train effluent and closed-loop cooling water clarity
- Food & beverage production: verification of final rinse water clarity prior to packaging line entry
FAQ
What regulatory standards does the 1720E comply with?
It conforms to USEPA Method 180.1, ISO 7027:2016, ASTM D6508, and Standard Methods 2130B.
Can the 1720E be used in pressurized pipelines?
Yes—the sensor is rated for continuous operation at up to 10 bar (145 psi) with appropriate mounting hardware and flow conditioning.
Is temperature compensation automatic?
Yes—internal thermistor provides real-time compensation across the full operating range (0–50°C for single-sensor configurations).
How often does the optical window require cleaning?
Under typical drinking water conditions, manual cleaning is required only during annual preventive maintenance; fouling-resistant quartz window coating extends intervals.
Does the 1720E support digital communication protocols beyond 4–20 mA?
Standard options include Modbus RTU over RS-485; EtherNet/IP and PROFIBUS DP-V1 are available as factory-configured options.
