초록 ▼

The vapor pressure of a multi-component liquid composition is measured by providing an eductor through which the liquid composition is caused to flow at selected inlet pressures to provide incrementally changing pressure differentials across the eductor. The pressure differential is read for each in

The vapor pressure of a multi-component liquid composition is measured by providing an eductor through which the liquid composition is caused to flow at selected inlet pressures to provide incrementally changing pressure differentials across the eductor. The pressure differential is read for each incremental change across the eductor and the suction port pressure is read at each incremental pressure differential until the suction port pressure as a function of the pressure differential indicates a change in slope or point of inflection along the so-called dead fluid curve indicating the bubble point or true vapor pressure of the liquid composition. A motorized pressure regulator valve may be interposed in the liquid composition flow conduit upstream of the eductor for incrementally changing the pressure differential. The point of inflection may be obtained by determining the mathematical relationship using the cubic spline fit technique and calculating the second derivative of the function of the suction port pressure versus the pressure differential across the eductor until the second derivative equals zero.

대표청구항 ▼

A method for determining the true vapor pressure of a multi-component liquid composition which typically exhibits, at a constant temperature, different vapor pressures due to the vaporization of compositions of different molecular weight in the liquid, comprising the steps of: providing an eductor h

A method for determining the true vapor pressure of a multi-component liquid composition which typically exhibits, at a constant temperature, different vapor pressures due to the vaporization of compositions of different molecular weight in the liquid, comprising the steps of: providing an eductor having an inlet port, a suction port, and an outlet port; passing a sample of liquid through said eductor at various flow rates while measuring the pressure differential between said inlet port and said outlet port and the pressure at said suction port, said pressure measurements being taken at a flow condition wherein a relatively low pressure differential between said inlet port and said outlet port is exhibited; and incrementally changing the flow rate while measuring the pressure differential between said inlet port and said outlet port and recording the suction port pressure at each incremental change in pressure differential at least until a point of inflection is observed in the proportional relationship between the pressure differential and the pressure at the suction port as an indication of the true vapor pressure of the liquid composition.