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Common Working Conditions and FAQs of Ultrasonic Open Channel Flow Meter for Liquid Measurement

September 19, 2022

This article will specifically analyze the common working conditions met when ultrasonic open channel flow meters are used to measure the liquids. Common working conditions include the following:

No.1-Steam

Steam here refers to the steam that affects the measurement.When there is steam on the water, if water droplets will condense on the probe, choose tetrafluoro emitting surface; otherwise, since it is working in the open air, there is no need to consider the influence of steam. Note that when the temperature of water and sewage exceeds 40°C, steam will be generated. And the higher the temperature, the greater the steam.

No. 2-with foam on the surface

To solve this, we can install 1 to 2 layers of perforated plates upstream of the installation point of the open channel flow meter to filter the foam.

No. 3-with floating objects on the surface

We can install 1 to 2 layers of perforated plates upstream of the installation point of the ultrasonic open channel flow meters to filter the foam. Or place the probe into a PVC pipe that is inserted the water and fixed. Note that use DN150 PVC pipe, and make the pipe 0.50 m higher than the highest water level, and the bottom of the pipe is cut at a 45° angle to allow water to flow in.

ultrasonic open channel flow meter

No. 4-Temperature

Its working temperature range is -20℃~ + 80℃, here refers to the air temperature around the probe, not that of the liquid to be measured. What happens if the temperature is less than -20℃? 1. It works fine when the temperature is less than -20℃ and greater than -25℃. 2. The LCD screen does not display. 3. It still measures, with 4-20mA output. 4. At such a low temperature, the emitting surface of the probe often freezes or frosts, which cannot be measured normally.

How it works when the temperature is below -20℃? We can install the flow meter in an instrument box that is equipped with an automatic heating device. When it is powered on, it will start automatic heating.

What should I do if the probe freezes? Bind the probe with electric heating cable connected to automatic temperature control device. The minimum temperature is set to less than 5℃and it starts to automatically heat.

No. 5-Corrosive liquids

To measure corrosive liquids, we can PVDF probe. We currently know there are two liquids that open channel flow meter can not measure, ammonia and pyridine.

No. 6-Output signals

Different outputs including standard output signal, non-standard output signal, digital signals and switch signals are all supported.

No. 7-Crystallization and volatilization

As the ultrasonic open channel flow meter works in the open air, there is no need to consider the influence of crystallization and volatilization For more working conditions and questions, you can contact Holykell engineers for professional solutions.