SU1449868A1 - Disk-type viscosimeter - Google Patents

Abstract

The invention relates to a technique for determining the rheological characteristics of fibrous suspensions by measuring their viscosity under shear. The purpose of the invention is to expand the range of concentrations, varying the accuracy of viscosity determination in a wide range of velocity gradients while maintaining a high homogeneity of the fiber suspension. The movable disk is equipped with a nozzle for axially feeding the fiber suspension, in the gap between the disks an agitator is installed along the vertical axis of the viscometer, and the stationary disk is made of a series of rings, each of which is mechanically connected with a force sensor. The surface of the rings, in contact with the fibrous suspension, is made with a coating of fibers, 2 silt. (With co

Description

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The invention relates to a technique for determining the rheological characteristics of fiber suspensions by measuring their viscosity under shear conditions and can be used in the pulp and paper industry for laboratory research and factory testing of paper pulp.

The purpose of the invention. is an extension of the concentration range of the measured suspensions and an increase in the accuracy of viscosity determination in a wide range of velocity gradients while maintaining a high homogeneity of the fiber suspension.

On fig.I presents a diagram of a disk viscometer; figure 2 is a top view.

The disk viscometer contains a lower RI movable (rotating) disk 1, which has a hole centered on the center and is provided with a nozzle 2. The upper fixed disk 3 is a set of rings that have viewing windows 4 and are concentric with each other. Disks 1 and 3 are separated by a gap. The surface of the rings, not occupied by the inspection windows 4 and in contact with the inspected fiber suspension, is made with a fiber coating. The rings with the help of Kontinain 5 are fixed with bearings O with respect to the guide 6, which forms with the support 7 a kinematic screw – nut pair. The screw is a guide, 6, and the nut is a stand 7, and the guide 6 has the ability to move along the vertical axis of the viscometer in order to adjust the size of the gap. An agitator 9 is mounted on the shaft 8 passing inside the guide 6 in the gap between the disks along the vertical axis of the viscometer. The taller beam 10 mechanically connects the disk 3 to the sensitive element through the bracket 5: 1 dash shear force measurement. The shear force is recorded by an appropriate recording device 12.

The viscometer works as follows.

The initial fibrous suspension is fed continuously by the pump through the nozzle 2 onto the mixer 9. The impact of the mixer 9 causes dispersion of the fibrous suspension, which becomes homogeneous

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centration, there are no clumps of fibers and floccules. Simultaneously with dispersing, the stirrer 9 directs the slurry into the viscometer gap. When moving along the gap in a uniform, fibrous suspension, due to the rotation of the lower disk 1, a shear flow is performed along the width of the gap. When moving in the gap in the fiber suspension, two velocity components arise radially and circumferentially. At the actual diameters of the disks 1 and 3, the value of the circumferential component is much greater than the value of the radial component, which allows the radial component not to be included in the construction of the rheological characteristic. The magnitude of the shear force is recorded by a shear force sensor corresponding to each ring, from which the signal enters the recording device 12. At low revolutions of the disk 1, the magnitude of the marginal shear force is recorded from the first viscometer of the ring. Since the fibrous suspension is uniform in concentration, i.e. there is no phase separation, then the magnitude of the ultimate shear force is determined with a greater degree of accuracy. Further, as the suspension moves along the gap, its circumferential speed increases (with a constant number of revolutions of disk 1), and the amount of shear force is removed from the second ring, corresponding to an increase in the peripheral speed, i.e. the next portion of the rheological characteristic is determined, etc. Since there is a free flow of fiber suspension from the gap of the cigar meter, the absence of edge effects and secondary currents during operation of the viscometer is achieved, which also increases the accuracy of the measured y-shift and removes restrictions on the number of revolutions of the disk 1, which greatly expands the range of velocity gradients, which are determined by the number of revolutions of the engine, which causes the rotation of the disk 1.

Claims (1)

Invention Formula A disk viscometer consisting of two disks arranged with a controlled gap concentrically to each other, one of which is fixed and Associated with the force sensor, and another rotating, characterized in that, in order to expand the range of concentrations of the measured suspensions and improve the accuracy of viscosity determination in a wide range of gradients of speed while maintaining a high homogeneity of the fiber suspension, the disk rotates with a nozzle, for feeding a fiber suspension, which is mounted coaxially with a stirrer disposed in the gap, wherein the fixed disk is made of a set of independent rings mounted with the possibility of angular movement relative to each other, each ring being mechanically connected to a force sensor. Output suspensions B) {od suspension Figure 1 ten V / / 2 Thebes.2.