Portable dissolved oxygen analyzer is a commonly used instrument in water quality testing, environmental monitoring, industrial control and other fields, which can quickly and accurately measure the concentration of dissolved oxygen in water. In order to ensure the reliability and accuracy of the instrument, the portable dissolved oxygen analyzer needs to meet the following technical requirements:
1. Measurement range
Dissolved oxygen concentration: The range of dissolved oxygen concentration in water that can usually be measured is 0 to 20mg/L or wider, depending on the application requirements.
Dissolved oxygen saturation: Generally, measurement of dissolved oxygen saturation should be supported, with a range typically between 0 and 200%.
Measurement accuracy: The common accuracy requirement is ± 0.1mg/L or higher to ensure the reliability of the measurement results.
2. Measurement principle
Polarography: Measuring the concentration of oxygen through electrode reactions, commonly used in portable dissolved oxygen analyzers, with fast response and high accuracy.
Fluorescence method: Based on the principle of fluorescent probes, it is suitable for more complex or high-precision applications, but usually has a higher cost.
3. Response time
The response time for measuring dissolved oxygen should usually not exceed 60 seconds to ensure rapid acquisition of real-time data.
The instrument should be able to maintain a fast response speed even when the dissolved oxygen in the water sample changes rapidly (such as changes in water flow).
4. Temperature compensation
Temperature changes can affect the solubility of dissolved oxygen, therefore, the instrument should have automatic temperature compensation (ATC) function. The compensation range is usually from 0 ° C to 50 ° C.
For water environments with significant temperature fluctuations, accurate temperature compensation is crucial to ensure that measurement results are not affected by temperature fluctuations.
5. Battery life and portability
Battery life: The portable dissolved oxygen analyzer should have a long battery life, generally requiring continuous use for at least 10-20 hours after a single charge or battery replacement.
Size and weight: Easy to carry, moderate size, suitable for one handed operation, usually within 500 grams.
6. Data storage and display
Data storage: The instrument should support storing multiple measurement results, typically requiring at least 100 to 1000 pieces of data to facilitate later viewing and analysis.
Display screen: It should be equipped with a clear and easy to read LCD or LED display screen, which displays real-time information such as dissolved oxygen concentration, temperature, saturation, and battery level.
7. Calibration function
Portable dissolved oxygen meters typically require support for manual or automatic calibration to ensure their measurement accuracy in different water quality environments.
Calibration can be performed based on a known dissolved oxygen standard solution, with common calibration points including 0% saturation (zero calibration) and 100% saturation (saturated solution calibration).
8. Anti interference performance
The instrument should have a certain anti-interference ability and be able to work stably under different water quality conditions, such as salinity and acidity.
Especially in water samples with high turbidity, abundant aquatic plants, or oil stains, the performance of the instrument should not be affected.
9. Waterproof grade
Due to the fact that portable dissolved oxygen meters are typically used in outdoor environments, they should have a high level of waterproof and dustproof performance. The common requirement is IP67 or higher to ensure that the instrument can still function properly in rainy or splashing environments.
10. Interface and Communication
Data output: The instrument should be equipped with standard communication interfaces (such as USB, Bluetooth, RS232, etc.) to facilitate connection with computers, mobile phones, or other devices for data transmission and analysis.
Software support: The portable dissolved oxygen analyzer should provide supporting software that supports functions such as data recording, analysis, and export.
11. Operating environment
Temperature range: The instrument should adapt to a wide temperature range, typically operating between -10 ° C and 50 ° C.
Pressure range: In some special applications, the instrument should support a certain pressure range, especially in applications with high water depth.
12. Other functions
Bubble interference compensation: The presence of bubbles in water may affect the measurement of dissolved oxygen, and some portable dissolved oxygen meters may have automatic compensation for bubble interference.
Recording function: The portable dissolved oxygen analyzer should have the function of automatically recording measurement data, which can automatically save data according to the set time interval, facilitating water quality monitoring.
13. Price and Maintenance
The price of portable dissolved oxygen meters should consider their measurement accuracy and functionality, and the cost should be controlled within a reasonable range.
The electrodes of the instrument should be easy to replace, easy to maintain, and able to work stably for a long time.
summary
Portable dissolved oxygen analyzer is a very practical water quality monitoring tool, and its technical requirements mainly focus on measurement accuracy, response speed, temperature compensation, data storage, and instrument portability. To ensure that the instrument can work stably in different environments and applications, with high precision, good anti-interference ability, and convenient operating interface. When choosing a suitable portable dissolved oxygen analyzer, it is necessary to consider factors such as specific application scenarios, environmental conditions, and budget comprehensively.