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N,N-ไดเอทิล-1,4-ฟีนิลีนไดเอมีน (DPD) สเปกโตรโฟโตเมทรี

The conductivity of a solution is primarily determined by the concentration and mobility of its ions, which are charged particles that can move freely in the solution. When an electric field is applied, these ions move towards the electrodes of opposite charge, creating a current. The more ions there are in the solution, and the faster they can move, the higher the conductivity. Therefore, by measuring the current, a conductivity probe can determine the solution’s ion concentration and mobility, and hence its conductivity.

However, conductivity probes do not just measure the conductivity of a solution. They can also measure its flow rate. This is because the flow of a solution can affect its conductivity. For instance, if the solution is flowing rapidly, the ions may not have enough time to reach the electrodes, resulting in a lower current and hence a lower conductivity. Conversely, if the solution is flowing slowly, the ions may have more time to reach the electrodes, resulting in a higher current and hence a higher conductivity. Therefore, by measuring the conductivity, a conductivity probe can infer the flow rate of the solution.

To measure the flow rate, a conductivity probe typically uses a technique called thermal dispersion. This technique involves heating one of the electrodes and measuring the temperature difference between the heated electrode and a reference electrode. The heat from the heated electrode is carried away by the flowing solution, and the rate at which this heat is carried away is proportional to the flow rate. Therefore, by measuring the temperature difference, a conductivity probe can determine the flow rate.

In conclusion, conductivity probes are versatile devices that can measure both the conductivity and flow rate of a solution. They do this by applying a voltage across two or more electrodes immersed in the solution, and measuring the resulting current and temperature difference. The current gives a measure of the solution’s conductivity, while the temperature difference gives a measure of its flow rate. Understanding how conductivity probes measure flow is essential for those who rely on these devices for their operations, as it allows them to interpret the readings accurately and make informed decisions.