How to measure the liquid level when the ultrasonic level gauge is used on acetone
Ningbo Yokelink Machinery Co.,Limited , https://www.yokelink.com
Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
Recently, a customer purchased six of our POLO series two-wire explosion-proof ultrasonic level gauges to measure various chemicals such as liquid alkali, formaldehyde, sulfuric acid, and acetone. These devices are designed for use in hazardous environments where safety is critical.
After two weeks of operation, the customer reached out to report that while the gauges worked well for liquid alkali, formaldehyde, and sulfuric acid, there was a significant issue with the measurement of acetone. The readings showed an error of up to 30-40%, which was far beyond acceptable limits. I visited the site to investigate the problem and understand the situation on the ground.
The POLO series ultrasonic level gauge was installed at a distance of 4 meters from the bottom of the tank. In the field, the actual liquid level of acetone was 2 meters, but the device was showing only 1 meter. This discrepancy was due to the fact that the ultrasonic level gauge was set to a default sound speed of 331 m/s. However, acetone is a highly volatile substance, and the gas above the liquid has a different sound velocity than the one set in the device, leading to inaccurate measurements.
Our POLO series ultrasonic level gauges are equipped with a feature that allows users to adjust the sound speed setting. By modifying this value to match the actual sound velocity of the gas in the tank, the measurement accuracy can be significantly improved.
To solve the problem, we first calculated the actual sound velocity in the tank. The ultrasonic gauge measured the liquid level at 1 meter, meaning the sound wave traveled 6 meters (3 meters down and 3 meters back). Using the default speed of 331 m/s, the time taken was approximately 0.01812 seconds.
Next, we calculated the actual distance based on the real liquid level of 2 meters. The sound wave traveled 4 meters (2 meters down and 2 meters back). Using the same time, the actual sound velocity in the tank was found to be around 221 m/s.
We then accessed the hidden menu on the POLO series gauge by entering the password "0101" and adjusted the sound speed from 331 m/s to 221 m/s. After saving the changes, the gauge began showing a reading of 2.05 meters, very close to the actual level.
This case highlights how adjusting the sound speed setting can reduce large measurement errors. However, in volatile liquids like acetone, the gas composition may change over time, causing fluctuations in sound velocity. As a result, even after calibration, the accuracy might not be as high as when measuring non-volatile substances like water, but it typically remains within 5%.
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