Ultrasonic level sensing technology
The development of ultrasonic technology -- the use of sound waves traveling through air -- has centered around the process control industry, particularly in the area of bulk solid and liquid level sensing where features such as noncontact sensing, ease of installation, and superior accuracy have great appeal. This article discusses how ultrasonic level-sensing systems work, explains how changing conditions can cause their performance to deteriorate, and highlights recent microprocessor developments that allow ultrasonic systems to ignore these conditions and provide accurate and reliable outputs.
Using high-frequency sound waves to detect objects or measure distance is not new. Bats and dolphins have been using high-frequency sound as a tool for survival for millions of years. More recently, mankind has applied this technology for its own benefit. Early research and application centered on sonar [sound navigation and ranging] -- the use of sound waves traveling through water. Originally, most development activity was sponsored and funded by government defense agencies. However, subsequent underwater applications have been wide ranging.