Method of and apparatus for determining deposition-point temperature

An apparatus for analyzing the deposition rate of a normally-liquid petroleum-based composition having constituents in a solution which solidify and deposit on a surface where such surface is below a deposition-point temperature of the composition, the apparatus comprising:

• acoustic-wave sensing means having an exposed surface and an isolated surface, the exposed surface being in contact with the petroleum-based composition for detecting the presence of constituents deposited on the exposed surface and for generating an output signal in response to the deposition thereon;
• temperature varying means for causing the temperature of the exposed surface to drop below the deposition-point temperature of the constituents in the composition;
• and
• means for monitoring the rate of deposition of the constituents as a function of temperature of the exposed surface.

A method for analyzing a normally-liquid petroleum-based composition having constituents in a solution which solidify and deposit upon a surface when such surface is cooled below a deposition-point temperature of the composition, the method comprising the steps of:

• contacting the petroleum-based composition with at least one surface of an acoustic-wave device;
• actively cooling the one surface of the acoustic-wave device over a predetermined range of temperatures including the deposition-point temperature of the petroleum-based composition;
• activating the acoustic-wave device with an electrical circuit and measuring at least one parameter thereof which varies in response to deposition of the constituents;
• and
• measuring and recording the temperature of the one surface of the acoustic-wave device to determine if the constituents have deposited on the one surface.