Abstract: A method for cleaning the U-tube of the measurement cell of a densimeter, the measurement cell including an isothermic enclosure defining a measurement chamber closed by a stopper surrounded by a resilient seal, a U-tube extending inside the measurement chamber for containing a sample, the U-tube secured to the stopper at a base of the U-tube which includes free ends projecting outwardly from the measurement chamber to permit injection of the sample via an injection opening and evacuation of the sample via an evacuation opening, and means for causing the U-tube to vibrate. The method comprises, following a step of analyzing a sample, injecting a rinsing solvent into the injection opening of the U-tube, and subjecting the stopper to ultrasonic waves.

Abstract: A method for the accurate measurement of the density of a sample using a densimeter equipped with a measurement cell, a sample-containing U-tube including a ferromagnetic member, an insulated conductive reading plate maintained at a different potential relative to the U-tube, and an electromagnetic excitation winding. The method includes the steps of transmitting a synchronised rectangular excitation signal continuously to the U-tube to cause the U-tube to vibrate at resonance frequency, the vibration being represented by a sinusoidal resonance signal; determining the resonance frequency from the variations in the voltage at the terminals of the capacitor and deducing an approximate value of the density of the sample; controlling the pulse width of the rectangular excitation signal to maintain a predefined constant amplitude of the resonance signal; and deducing a correction factor dependent on the viscosity of the sample.

Abstract: A method for cleaning the U-tube of the measurement cell of a densimeter, the measurement cell including an isothermic enclosure defining a measurement chamber closed by a stopper surrounded by a resilient seal, a U-tube extending inside the measurement chamber for containing a sample, the U-tube secured to the stopper at a base of the U-tube which includes free ends projecting outwardly from the measurement chamber to permit injection of the sample via an injection opening and evacuation of the sample via an evacuation opening, and means for causing the U-tube to vibrate. The method comprises, following a step of analyzing a sample, injecting a rinsing solvent into the injection opening of the U-tube, and subjecting the stopper to ultrasonic waves.

Abstract: A method for the accurate measurement of the density of a sample using a densimeter equipped with a measurement cell, a sample-containing U-tube including a ferromagnetic member, an insulated conductive reading plate maintained at a different potential relative to the U-tube, and an electromagnetic excitation winding. The method includes the steps of transmitting a synchronised rectangular excitation signal continuously to the U-tube to cause the U-tube to vibrate at resonance frequency, the vibration being represented by a sinusoidal resonance signal; determining the resonance frequency from the variations in the voltage at the terminals of the capacitor and deducing an approximate value of the density of the sample; controlling the pulse width of the rectangular excitation signal to maintain a predefined constant amplitude of the resonance signal; and deducing a correction factor dependent on the viscosity of the sample.