Online Turbidity Meter

Online Turbidimeter

Basic Operation Manual

     Online Turbidimeter  

I. Measurement Principle

Io——Incident light

It——Transmitted light

Is——Scattered light

D——Solution turbidity

When a beam of parallel light of a specific spectrum passes through a solution, part of it is absorbed and scattered, and part of it passes through the solution. The intensity of the scattered light at a 90° angle to the incident light conforms to the Rayleigh formula:

Io——Incident light intensity      Is——Scattered light intensity        N——Number of particles per unit solution

V——Particle volume         λ——Wavelength of incident light        K——Coefficient

Under constant incident light conditions, within a certain turbidity range, the intensity of the scattered light is proportional to the turbidity of the solution. The above formula can be rearranged and rewritten as:

According to this formula, we can measure the turbidity of a water sample by measuring the intensity of the scattered light from particles in the water sample. This is the basic measurement principle of this product. The DZ series turbidimeter uses a combination of scattering and transmission principles for high turbidity measurements.

II. Basic Circuit Block Diagram

Schematic diagram of the scattered light structure instrument

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Schematic diagram of the transmitted light structure instrument

The photoelectric sensor consists of a light source, lens, photoelectric element, etc. When light passes through the measured liquid sample, the scattered light at a 90° angle to the incident light acts on the photoelectric element, generating an electrical signal that varies with turbidity. This signal, along with the reference signal, is sent to the signal processor.

The signal processor, centered around an integrated circuit, forms a stable electronic circuit that performs amplification, filtering, calculation, compensation, and other processing on the signal, making it linearly related to the turbidity of the measured liquid sample throughout the entire measurement range.

The regulated power supply consists of a transformer, rectifier, filter, voltage regulator module, etc., converting AC power that varies from 200 volts to 240 volts into the DC working voltage required by the instrument.

III. Structure Diagram

1. Turbidity sensor   2. Water inlet    3. Water outlet     4. Overflow port       5. Exhaust port

6. Power 220V   7. Signal output  8. Calibration potentiometer 9. Turbidity display meter 10. Signal output

11. Turbidity display panel 12. Hook    13. Power 220V

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The turbidity sensor is the key part of this instrument, containing photoelectric conversion devices, integrated circuit boards, stainless steel water tanks, etc., and requires extra care and maintenance. The turbidity display meter is preset and debugged at the factory, with a password inside, and users do not need to set it.

The calibration potentiometer is used to adjust the accuracy of the instrument. When the metrology authority calibrates this instrument, or when the user, after using the instrument for a long time, finds a deviation and confirms that the measurement value is inaccurate, and has zero-degree water and 10 NTU standard turbidity solution, the inspector or user can calibrate the instrument's accuracy themselves.

IV. Main Technical Performance

The DZG turbidimeter is designed according to the national requirements for water quality, the current drinking water production process in China, and the condition of China's water sources. It ensures the measurement accuracy requirements for finished water while also considering the needs for detecting settled water and source water. It uses a four-digit display, providing simple and accurate readings with high precision. It maintains three significant decimals within 0-10 NTU and two significant decimals within 11-100 NTU.

The turbidimeter's range can be divided into 1-10, 0-20, 0-100, 0-500, 0-2000 NTU, etc.

V. Usage Method

(1) Installation and Fixing

1. Fix the instrument on the wall, connect the water source to the water inlet with a hose, install a water inlet valve at the water source, and tighten the water inlet with a hose clamp (provided by the manufacturer) to prevent water leakage. Then connect the hose to the overflow port and water outlet (the hose length depends on the working environment), and also tighten it with a hose clamp (provided by the manufacturer). Clamp the water outlet halfway, slowly open the water source switch, and water will enter the water tank. Part of it will flow out from the water outlet, and another part will overflow from the overflow port as the water level rises. When a small amount of overflow water flows out from the overflow port, the water tank is full, and both the water outlet and overflow port have water flowing out. You can adjust the water inlet valve of the water source and the opening of the water outlet clamp to regulate the water flow, but the small amount of overflow from the overflow port must not be interrupted (Note•This is key). If the overflow port has no

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overflow water flowing out, please increase the water inflow or clamp the plastic tube of the water outlet a bit tighter to reduce the water flow at the water outlet, ensuring that the overflow port has overflow water flowing out, the water path is clear, and the instrument works normally.

2. Wiring

Turbidity display meter

Connect the signal line of the turbidity sensor to the input terminals 1 and 2 of the display meter, connect the 220V power supply to terminals 5 and 6, and connect the 4-20mA output to terminals 3 and 4.

(2) Usage Method

1. When using the instrument for the first time, please run it for 24 hours before testing.

2. Calibration: Use a non-continuous turbidimeter to measure the turbidity of the water at the outlet, and rotate the calibration potentiometer so that the digital display on the meter head shows the turbidity value of the outlet water.

4. After the turbidimeter is running normally, it outputs 4-20mA. 20mA corresponds to the full scale.

5. After about ten thousand hours of use, if the optical window is excessively dirty and the operational error is large, please clean the window.

7. When cleaning the window, turn off the water source, cut off the power, unscrew the three screws on the top of the instrument, remove the instrument panel, follow the instructions on the core, use a wrench to unscrew the screws at both ends of the stainless steel pressure plate, open the cleaning window, be careful not to drop the O-ring, use tweezers to hold an alcohol cotton ball to clean the optical window, then install the cleaning window, use a wrench to tighten the screws at both ends of the stainless steel pressure plate, pay attention to balance, close the cleaning window, and the cleaning work is completed.

Please calibrate according to the usage method. The instrument has been adjusted with special equipment before leaving the factory.

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The zero point does not need to be adjusted by the user.

8. Do not disassemble the instrument to avoid affecting or damaging the instrument's performance.

VI. Precautions

1. The hose clamps at the water inlet, water outlet, and overflow port must be tightened to prevent water leakage.

2. When water comes out of the exhaust port, reduce the water inlet valve to ensure no water flows out.

3. The overflow port must have water flowing out.

VII. Turbidity Standard

The DZG series turbidimeter uses the formazin polymer standard specified in GB5750-85 (8). For its preparation method, please refer to Article 6.2 of GB5750-85 (8).

It can be purchased by mail from our factory or contacted from the National Standard Material Center.

VIII. Common Faults and Troubleshooting

IX. Standard Accessories

1. Certificate of conformity

2. User manual

Turbidity - Flow-through Installation Picture

Turbidimeter Wiring