US 6,412,337 B1 · Apparatus and method for measuring the rheological properties of a power law fluid

Abstract

The apparatus (10) is used for determining the consistency index (k) and the power law index (n) of a Newtonian fluid or non-Newtonian power law fluid. A method is also disclosed. Accordingly, the fluid flows in a laminar manner through a first (12) and a second static mixer (14) successively connected together by means of an intermediary pipe (18). A first pressure differential (ΔP1) corresponding to a pressure drop of the fluid through the first static mixer (12) is measured. Similarly, a second pressure differential (ΔP2) corresponding to a pressure drop of the fluid through the second static mixer (14) is measured. Finally, the consistency index (k) and the power law index (n) are calculated using the Metzner and Otto concept generalized to static mixers. The apparent viscosity may also be calculated. This invention may be mounted directly on a main supply pipe (16) and allows the rheological properties of the fluid to be known in real time. It also improves the mixing of the fluid and maintains its homogeneity.

Claims22

Dependent claims

A method for determining the consistency index (k) and the power law index (n) of a fluid exhibiting a power law behavior when flowing through a pipe having an internal diameter (D), the fluid flowing in the pipe with a mean flow velocity (V), the method comprising the steps of:

passing the fluid in a first and a second static mixer through which the fluid flows in a laminar manner, the first and the second static mixer being in fluid communication with each other and being non-identical, the first static mixer having predetermined geometrical constants KS1 and KP1 and the second static mixer having predetermined geometrical constants KS2 and KP2;
measuring a first pressure differential (ΔP1) corresponding to a pressure drop of the fluid through the first static mixer;
measuring a second pressure differential (ΔP2) corresponding to a pressure drop of the fluid through the second static mixer;
and
calculating the consistency index (k) and the power law index (n) using the first and second pressure differentials (ΔP1, ΔP2), the mean flow velocity (V), and the geometrical constants KS1, KP1, KS2, and KP2 according to an approximation of Metzner and Otto concept generalized to static mixers.

2 more elements

An apparatus for measuring the consistency index (k) and the power law index (n) of a fluid exhibiting a power law behavior when flowing through a pipe having a given diameter (D) and with a mean flow velocity (V), the apparatus comprising:

a first static mixer having an inlet and an outlet, the inlet of the first static mixer being connected to the pipe, the first static mixer having predetermined geometrical constants KS1 and KP1;
a second static mixer having an inlet, an outlet, and being non-identical to the first static mixer, the outlet of the second static mixer being connected to the pipe, the second static mixer having predetermined geometrical constants KS2 and KP2;
an intermediary pipe connected between the outlet of the first static mixer and the inlet of the second static mixer;
first means for measuring a first pressure differential (ΔP1) corresponding to a pressure drop of a laminar flow of the fluid through the first static mixer;
second means for measuring a second pressure differential (ΔP2) corresponding to a pressure drop of the laminar flow of fluid through the second static mixer;
and
means for calculating the consistency index (k) and the power law index (n) according to an approximation of Metzner and Otto concept generalized to static mixers.

4 more elements

An apparatus for measuring the consistency index (k) and the power law index (n) of a fluid exhibiting a power law behavior when flowing through a pipe, the apparatus comprising:

a first static mixer having an inlet and an outlet, the inlet of the first static mixer being connected to the pipe, the first static mixer having predetermined geometrical constants KS1 and KP1;
a second static mixer having an inlet and an outlet, the outlet of the second static mixer being connected to the pipe, the second static mixer having predetermined geometrical constants KS2 and KP2, where KS2 is non-identical to KS1;
an intermediary pipe mounted between the outlet of the first static mixer and the inlet of the second static mixer;
a first pressure cell mounted on the pipe before the inlet of the first static mixer;
a second pressure cell mounted on the intermediary pipe;
a third pressure cell mounted on the pipe after the outlet of the second static mixer;
a first differential pressure transducer connected between the first and the second pressure cell, the first differential pressure transducer having an output terminal for a first pressure differential signal (ΔP1) indicative of a pressure drop of the fluid through the first static mixer;
a second differential pressure transducer connected between the second and the third pressure cell, the second differential pressure transducer having an output terminal for a second pressure differential signal (ΔP2) indicative of a pressure drop of the fluid through the second static mixer;
and
a computer having a subroutine in which the consistency index (k) and the power law index (n) are calculated according to an approximation of Metzner and Otto concept generalized to static mixers.

7 more elements

Dependencies are inferred from the claim text.

Apparatus and method for measuring the rheological properties of a power law fluid

Life of this patent

Apparatus and method for measuring the rheological properties of a power law fluid

Life of this patent

Abstract

Claims22