CZ303325B6 - Measuring cell for measuring friction parameters of particulate matter on boundary conditions - Google Patents

Abstract

In the present invention, there is disclosed a shear cell for measuring dependence of particulate matter internal friction angle on boundary conditions comprising a bottom (1), a sidewall (2) and a lid (3). The sidewall (2) is divided by a plane (4) into a first portion (22) and a second portion (21). The second portion (21) is coupled with the bottom (1). Internal space of the first portion (22), there is slidably mounted the lid (3). Cross section through the sidewall (2), performed in the plane (4) that divides the sidewall (2) into the first portion (22) and the second portion (21), comprises at least two straight sections (63, 64) that are parallel to each another.

Description

Measuring cell for measurement of friction parameters of particulate matter at boundary conditions

Technical field

The invention relates to the measurement of the dependence of the internal friction angle of a particulate matter on boundary conditions both in the field of science and research and for the purposes of process and construction engineering and solves simulation of the actual particulate matter particle flow process under real conditions. The measurement by shear test is assumed that during this test, a measured value of the internal friction angle measured up to its minimum value is reached for the measured sample.

BACKGROUND OF THE INVENTION

The internal friction angle is determined by the nature of the particulate matter and depends on the friction and boundary conditions. In practice, it is advantageous to carry out a laboratory simulation of the internal friction angle that corresponds to real conditions.

It is known that the dependence of particulate matter flow parameters on the normal force magnitude is determined on a shear machine containing a shear cell. The known shear cell has the shape of a cylindrical container with a flat bottom and has a horizontal planar lid. The side wall formed by the cylinder shell is divided by a plane parallel to the bottom plane into a lower part and an upper part. The lid has a circular plan and is slidingly adjusted in the upper part. The cap is subjected to a normal force in the vertical direction during measurement, while the upper part is subjected to a tangential force in the horizontal direction. Inside the vessel there is a space to accommodate particulate matter particles. The disadvantage of detecting particulate matter parameters in a circular floor plan is that the tangential and normal force dependencies found do not apply to the minimum or maximum values of the internal friction angle and are therefore difficult to transfer to practice. Therefore, the values thus determined are not universally valid and can only be applied in practice in practice. A further disadvantage is that the measured values, which do not respect the mechanisms of mutual transfer of particles, are in practice put into equations that do not respect the boundary conditions for which these equations were derived. These are mainly the deformation compatibility and the deformation of stress areas.

SUMMARY OF THE INVENTION

These disadvantages are solved by a measuring cell for measuring the frictional parameters of the particulate matter at the boundary conditions according to the invention, comprising a bottom, a side wall and a lid. The side groans are divided in plane into first and second parts. In the first side wall part there is a sliding lid, while the second side wall part is connected to the bottom.

It is an object of the invention that the cross-section of the side wall taken in a plane dividing the side wall into the first and second parts comprises at least two straight sections interconnected by two semicircular sections of the same diameter. The two straight sections are parallel to each other.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is an axonometric view of a shear cell according to an exemplary embodiment; Figure 2 is a plan view of the same shear cell. Fig. 3 is a section A-A of Fig. 2. Figs. Figure 4 shows the same as Figure 3 except that this is a situation during measurement.

- 1 GB 303325 B6

Examples of embodiments of the invention

The shear cell according to an exemplary embodiment is intended to be placed in a device capable of producing a tangential force 10 and at the same time a normal force 5. The shear cell has a bottom 1, a side wall 2 and a lid 3. The lid 3 has a shape in the space limited by the inner surface of the side wall 2 freely movable in the vertical direction. The side wall 2 is divided by a plane 4, parallel to the bottom 1, into a second part 21 and a first part 22. Thus, the inner space of the shear cell is divided into a first space 72 and a second space 71. the side wall 2 on the first part 22 and on the second part 21, comprises two straight sections 63, 64 interconnected by two semicircular sections 61, 62 of equal diameter. The straight sections 63, 64 are parallel to one another.

Before determining the dependence of the internal friction angle 8 of the particulate matter 8 on the boundary conditions, the first side wall panel 22 is placed on the second sidewall part 2 and the shear cell is filled with particulate matter particles 8 above plane 4. At the same time, the cap 3 is simultaneously applied in the vertical direction by a normal force 5 and at the same time a tangential force 10 is applied to the first part 22 of the shear cell in the direction of its longitudinal axis. against the second part

21. The time course of the tangential force W is measured by a load cell (not shown). The measurement of the dependence of the non-constant angle of internal friction of the particulate matter on the boundary conditions, up to its minimum value, for the same particulate matter particles 8 is performed for different combinations of values of tangential force 10 and normal force 5.

Industrial applicability

The invention can be used to identify the mechanical-physical properties of a particulate material that can subsequently be applied in the areas of transportation, handling, storage and technological processes with particulate matter.

Claims (1)

PATENT CLAIMS A shear cell for measuring the dependence of the internal friction angle of a particulate matter on boundary conditions, comprising a bottom (1), a side wall (2) and a lid (3), wherein the side wall (2) is divided by plane (4) into a first part (22). ) and a second part (21), the lid (3) being slidably provided in the first part (22) of the side wall (2), while the second part (21) of the side wall (2) is connected to the bottom (1), characterized in that the cross-section of the side wall (2) taken in the plane (4) dividing the side wall (2) into the first part (22) and the second part (21) comprises at least two straight sections (63, 64) interconnected two semicircular sections (61, 62) of the same diameter, the two straight sections (63, 64) being parallel to each other.