Apparatus for measuring the representative parameters of rheological properties of viscoelastic fluids
First Claim
1. Apparatus adapted to determine representative parameters of rheological properties of viscoelastic liquids, particularly dilute solutions of macromolecular compositions, said apparatus including means for translating the difference between the behavior of said liquids during flow and beyond a critical strain rate with the behavior of a Newtonian liquid having a viscosity equal to that of the viscoelastic liquid ascertaining by the relationship between strain rate and the resulting stress in the two liquids, said appartus comprising:
- (a) a pair of similar cylinders each terminating at one end in a calibrated thin wall orifice;
(b) a pair of pistons adapted to slide within the cylinders and adapted to be pushed conjointly towards the ends of the cylinders by a motor;
(c) blockable filling means connecting each of said cylinders to a respective reservoir of liquid, one of said reservoirs adapted to hold a viscoelastic liquid and the other of said reservoirs adapted to hold a Newtonian comparison liquid;
(d) first differential pressure measurement means including two conduits, each of said conduits opening into a respective one of said cylinders immediately upstream of one of said calibrated end orifices;
(e) control means coupled to said motor to adjust its speed upwardly along a predetermined increasing range of speeds selected such that the strain rate of the liquid flow in each of the calibrated orifices has a minimal speed which is lower than and a maximum speed which is several times greater than the critical strain rate of the viscoelastic liquid; and
(f) registration means for correlating respective data couples gathered from the control means and from the first differential pressure measurement means, the entire registered dats representing the relationship between the differential stress and the strain rate.
1 Assignment
0 Petitions
Accused Products
Abstract
Apparatus for determining rheological parameters of viscoelastic fluids is provided. The apparatus comprises two similar cylinder-piston assemblies ending at identical flow orifices. The pistons are pushed conjointly by a motor at an adjusted speed. A differential manometer is arranged between the cylinders immediately upstream of the orifices. One of the cylinders contains fluid to be studied and the other a Newtonian comparison fluid. The strain rates of the fluids are defined by the adjusted flow rates, and the pressure differential expresses elongation stress of the viscoelastic fluid. This apparatus is applicable in the rheological study of dilute solutions of macromolecular compositions.
-
Citations
22 Claims
-
1. Apparatus adapted to determine representative parameters of rheological properties of viscoelastic liquids, particularly dilute solutions of macromolecular compositions, said apparatus including means for translating the difference between the behavior of said liquids during flow and beyond a critical strain rate with the behavior of a Newtonian liquid having a viscosity equal to that of the viscoelastic liquid ascertaining by the relationship between strain rate and the resulting stress in the two liquids, said appartus comprising:
-
(a) a pair of similar cylinders each terminating at one end in a calibrated thin wall orifice; (b) a pair of pistons adapted to slide within the cylinders and adapted to be pushed conjointly towards the ends of the cylinders by a motor; (c) blockable filling means connecting each of said cylinders to a respective reservoir of liquid, one of said reservoirs adapted to hold a viscoelastic liquid and the other of said reservoirs adapted to hold a Newtonian comparison liquid; (d) first differential pressure measurement means including two conduits, each of said conduits opening into a respective one of said cylinders immediately upstream of one of said calibrated end orifices; (e) control means coupled to said motor to adjust its speed upwardly along a predetermined increasing range of speeds selected such that the strain rate of the liquid flow in each of the calibrated orifices has a minimal speed which is lower than and a maximum speed which is several times greater than the critical strain rate of the viscoelastic liquid; and (f) registration means for correlating respective data couples gathered from the control means and from the first differential pressure measurement means, the entire registered dats representing the relationship between the differential stress and the strain rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
-
-
21. A method for determining representative parameters of rheological properties of viscoelastic liquids, particularly dilute solutions of macromolecular compositions, the method utilizing which apparatus includes means for translating the behavioral difference between said viscoelastic liquids during flow and beyond a critical strain rate with the behavior of a Newtonian liquid having a viscosity equal to that of the viscoelastic liquids by relating the strain rate and the resulting stress of the two liquids, the method comprising:
-
(a) filling one cylinder with a viscoelastic fluid and a second cylinder with a Newtonian comparison fluid; (b) conjointly forcing said fluids through said cylinders in the same direction by driving a piston within each of said cylinders; (c) drawing a portion of the fluid from each of cylinders upstream and adjacent to an orifice positioned at an end of each of said cylinders; (d) conducting said fluid portions into a first differential pressure measurement means; (e) verifying the equality of the viscosity of said fluids by assuring that said differential pressure measurement means is in equilibrium; (f) increasing the speed of a motor with control means for driving said pistons by discrete, predetermined amounts; and (g) plotting a point corresponding to a pair of correlated values derived from said first differential pressure measurement means and said control means. - View Dependent Claims (22)
-
Specification