Working Principle

W761-DCL2.2 mainly consists of two parts: the control panel and the Germany-made CL2.2 free chlorine sensor. The controller displays the disinfectant value (main measured value), the pH value of the aqueous solution (a pH electrode is required for selection), and the working status. It outputs signals such as analog, digital, and switching signals.

The free chlorine sensor Adopts a coated amperometric dual-electrode measurement system, with the core principles as follows:

1. Detection Target: Only detects hypochlorous acid (HOCL) in water; cannot detect hypochlorite (anionic form); only applicable to inorganic chlorinating agents (chlorine gas, sodium hypochlorite, calcium hypochlorite, chlorine generated by membrane electrolysis); cannot detect organic chlorinating agents (e.g., cyanuric acid-based products).

2. Signal Processing: Integrates a temperature sensor to achieve automatic temperature compensation, and outputs compensated signals—analog signals (4~20 mA or 0~±2V) and digital signals (Modbus RTU, via RS485 interface).

3. Calibration Requirements: Zero-point calibration is not required; slope calibration must be performed using the DPD-1 method (colorimetric method, DPD testing equipment needs to be purchased separately); after calibration, the pH value must remain stable (fluctuation < 0.05); otherwise, a sensor with lower pH dependence should be selected.

4. pH Impact: The concentration ratio of hypochlorous acid (HOCL) depends on the pH value; pH changes will cause measurement slope loss (e.g., approximately 60% slope loss at pH=8, and approximately 80% at pH=8.5, with pH=7 as the reference).

Application

Core adaptation to high-salt concentration water bodies, with specific scenarios as follows:

1. Basic Environment: Brine or seawater with a salt concentration of 3.5%~26% (conductivity > 50mS).

2. Specific Applications:

◦ Disinfection monitoring of drinking water and swimming pool water;

◦ Disinfection monitoring of slightly polluted process water and cooling water treatment;

◦ Must be used with a dedicated flow cell to ensure the water flow meets requirements.

Product Features

1. High-Salt Adaptability: Specifically designed for brine/seawater with a salt concentration of 3.5%~26%, and resistant to high-salt environments.

2. Advantages of Measurement System: Dual-electrode structure improves measurement stability; fast response time (T90 ≈ 30 seconds).

3. Easy Operation: Integrates temperature compensation, no zero-point calibration required; can be directly connected to a dedicated transmitter, supporting "one-click calibration".

4. Environmental Requirements:

◦ Water flow must be controlled at 15~30 L/H (in the flow cell);

◦ The water to be measured must be drinking water or clean water, free of solids and surfactants (e.g., detergent components);

◦ Only one type of disinfectant can be used at a time to avoid interference.

1. Slope Characteristics: The sensor slope fluctuates depending on the manufacturer/application (65%~150% of the nominal slope); it is recommended to determine the suitable measurement range by multiplying the concentration to be measured by 1.5 (e.g., if the concentration to be measured is 1.6ppm → a measurement range of 5ppm is recommended).

Technical Parameters

FAQ – Frequently Asked Questions

1. Where are your products manufactured?

Our products are proudly designed and manufactured in China, following international quality standards and certified processes.

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Absolutely. Our products are tested to meet CE, RoHS, and other international certifications.

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5. Can I get product samples before placing a large order?

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For standard products, we usually ship within 5–7 days after order confirmation. Customized products may take slightly longer.

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Yes, we offer remote technical assistance, manuals in English, and prompt solutions to any issues, ensuring smooth use worldwide.

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