A rotary tank assembly is provided for a liner. The liner is structured to apply a compound to a plurality of container closures. The rotary tank assembly includes a compound tank, a fill tube structured to fill the tank with a volume of the compound to a desired level, a sensor assembly adapted to measure the level of the compound within the compound tank, and a rotary union assembly structured to pivotably couple the fill tube and the sensor assembly to the compound tank. The sensor assembly only requires one single probe.

A rotary tank assembly is provided for a liner. The liner is structured to apply a compound to a plurality of container closures. The rotary tank assembly includes a compound tank, a fill tube structured to fill the tank with a volume of said compound to a desired level, a sensor assembly adapted to measure the level of said compound within the compound tank, and a rotary union assembly structured to pivotally couple the fill tube and the sensor assembly to the compound tank. The sensor assembly only requires one single probe.