Fluid level detection apparatus, fluid level detection method, and computer-readable medium containing fluid level detection program

A fluid level detection method comprising:

• providing a vibrator and a vibration sensor on an outer wall surface of a container at respective positions that interpose, from above and below, a fluid level of a fluid provided in the container, the vibrator being configured to apply a vibration to the container that contains the fluid, the vibration sensor being configured to detect a vibration wave that is generated by the vibrator and propagates through the container;
• calculating, with a controller, a height of the fluid level, on a basis of the vibration wave detected by the vibration sensor;
• causing, with the controller, the vibrator to generate, as the vibration, an ultrasonic vibration that covers a predetermined frequency range, and
• calculate, with the controller, as the height of the fluid level, a nominal value of the height of the fluid level on a basis of a high frequency component in the vibration wave detected by the vibration sensor, and correct the nominal value on a basis of a low frequency component in the vibration wave detected by the vibration sensor, the high frequency component being higher than a first predetermined frequency, the low frequency component being lower than a second predetermined frequency.

A non-transitory computer readable medium containing a fluid level detection program, the fluid level detection program causing, when executed by a computer, the computer to implement a method, the method comprising:

• providing a vibrator and a vibration sensor on an outer wall surface of a container at respective positions that interpose, from above and below, a fluid level of a fluid provided in the container, the vibrator being configured to apply a vibration to the container that contains the fluid, the vibration sensor being configured to detect a vibration wave that is generated by the vibrator and propagates through the container;
• calculating a height of the fluid level, on a basis of the vibration wave detected by the vibration sensor;
• causing the vibrator to generate, as the vibration, an ultrasonic vibration that covers a predetermined frequency range, and
• calculate as the height of the fluid level, a nominal value of the height of the fluid level on a basis of a high frequency component in the vibration wave detected by the vibration sensor, and correct the nominal value on a basis of a low frequency component in the vibration wave detected by the vibration sensor, the high frequency component being higher than a first predetermined frequency, the low frequency component being lower than a second predetermined frequency.