ASSEMBLY FOR SENSING AND/OR MONITORING A PREDETERMINED LEVEL IN A VESSEL

摘要

An assembly for sensing and/or monitoring the level of a material in a vessel includes a level sensor mounted in the vessel so that it comes into contact with the material when the material has attained a predetermined level. The level sensor contains a low-frequency sensing system and a high-frequency sensing system. The low-frequency sensing system is formed by a mechanical vibrator system induced to vibrate at its natural resonant frequency, and establishing whether the mechanical vibrator system is in contact with the material or not is achieved by evaluating the frequency and/or amplitude of the mechanical vibrations. For forming the high-frequency sensing system high-frequency elastic vibration is induced in a component of the level sensor, and establishing whether this component is in contact with the material or not is achieved by evaluating an electric signal generated as a function of the high-frequency elastic vibration.