Tuning fork vibration-type viscosity measuring apparatus

A vibration-type viscosity measuring apparatus having a measuring unit for measuring the viscosity and the temperature of a sample at the same time, said measuring unit comprising:

• (a) a support block firmly fixed to a base frame and having a support column at a lower section of the support block;
• (b) tuning fork vibrator means fixed to said support block and extending downward from the support block, the tuning fork vibrator means having a pair of vibrator subassemblies arranged on opposite sides of said support column to undergo vibrating movement, each of the vibrator subassemblies having at its free end a thin flat sensor plate placeable in a sample during the measurement of the sample viscosity, each sensor plate being arranged in the same imaginary vertical plane;
• (c) means for driving said pair of vibrator subassemblies at the same frequency in reverse phase relation to each other;
• (d) means for detecting the vibration amplitude of said pair of vibrator subassemblies which varies due to a viscosity resistance applied to the sensor plates when placed in the sample and for converting the vibration amplitude into an electrical signal;
• (e) a thermometer secured to the lower end of said support column, situated at an intermediate point between said sensor plates of the pair of vibrator subassemblies, and arranged in the same imaginary vertical plane where the sensor plates are arranged, the thermometer having a probe which can be immersed in the sample together with the sensor plates;
• (f) a sample container for containing therein the sample to be measured;
• and
• (g) adjusting means for adjusting a relative distance between said sensor plates and probe and said sample container so that depths of the sensor plates and probe immersed in the sample stored in said sample container can be adjusted, said adjusting means including carrier means mounted movably in an axial direction of said support column at the lower end of said support column, the carrier means detachably carrying thereon said sample container so that said sample container can be moved together with said carrier means in the axial direction of said support column.

An apparatus for measuring a viscosity of a liquid sample, comprising:

• a support having a shaft extending downwardly from the support;
• a pair of longitudinal vibrating means fixed to and extending downwardly from the support in opposed relation relative to the shaft to undergo vibrating movement, each of the longitudinal vibrating means having a center line of vibration about which the vibrating means vibrates and a center of gravity aligned on the center line of vibration, the longitudinal vibrating means having at their free ends a respective flat plate lying in and vibrating along the same plane parallel to the shaft;
• driving means disposed between the pair of vibrating means and the shaft to effect the vibration of the pair of vibrating means at the same frequency in opposite phase relation to each other;
• detecting means operative when the flat plates are immersed in a liquid sample for detecting a vibration amplitude of the vibrating means indicative of a viscosity of the liquid sample;
• and sensing means mounted at a lower end of the shaft and disposed in the same plane at an intermediate point between the flat plates for sensing a temperature of the liquid sample in contact with the liquid sample during the measurement of the liquid sample viscosity.