JPS6122273Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a test device for measuring the mechanical properties of powder and granules, and in particular, the powder and granules are filled in an annular space, and the powder is pressed in the direction of the annular axis. A shearing force is generated in the granular material layer by creating a swirling motion in the lower part of the body layer, and the fracture envelope of the granular material is determined by measuring the shear force and the pressing force, that is, the vertical force. This invention relates to a powder shear testing device for determining mechanical properties such as friction coefficient, adhesion stress, uniaxial collapse stress, maximum consolidation stress, and wall friction coefficient.

In recent years, granular materials have been used in various industrial fields, but it is extremely important to accurately understand the mechanical properties of granular materials, such as when designing equipment for handling granular materials and optimizing operating methods. It is becoming. In particular, the design of the strength of storage tank walls such as bunkers and silos, the determination of storage tank outlet dimensions, the calculation of the required power when transporting powder and granular materials by air, and the pressurization of powder, etc. Mechanical properties are essential. For this reason, several powder shear test devices have been proposed.

The prior art will be explained below with reference to the drawings.

FIG. 1 is a fragmented sectional view showing the configuration of a conventional device of this type. Base 1 with a rigid bearing in the center
An annular pedestal 6 having a concave portion on the upper surface is fixed to the upper surface of the bearing so as to be coaxial with the bearing. Pedestal 6
A plurality of ball bearings 5 are placed in the recess, and a disc-shaped rotary pedestal 4 having an annular recess on the upper surface is loaded via the ball bearings 5, and a shaft protruding from the center of the lower end of the rotary pedestal 4. is fitted into the bearing, and has a structure that is free to rotate on a plane. A lid 2 having a protrusion that fits into the annular recess of the rotary pedestal 4 is placed on the upper part of the rotary pedestal 4, and the central axis of the lid 2 is mounted on a bearing provided on the central axis of the rotary pedestal 4. are engaged with each other and are mounted so that they can freely rotate relative to each other. The annular space formed by the lid 2 and the annular recess of the rotary pedestal 4 is filled with powder to form a powder layer 3, and on the lid 2 is a circular plate having a through hole in the center. A weight 10 of the shape is loaded. The other end of the bar 8, which has one end fixed to the outer periphery of the lid 2, is connected to a rotating dynamometer 9, which is supported on the base 1 by a support member 11. The rotating base 4 has a structure that is horizontally rotated by a drive device 7. Although not particularly shown, a power transmission mechanism consisting of a rack, pinion, etc. is interposed between the drive device 7 and the rotary base 4.

In this configuration, when the rotating base 4 is rotated, the powder layer 3 rotates.
is sheared between the lid 2 and the rotating base 4, and the shear force at this time is measured by a rotary dynamometer 9. The normal force acting on the powder/granule layer 3 is calculated by dividing the weight of the weight 10 and the lid 2 by the horizontal cross-sectional area of the powder/granule layer 3.

However, in this configuration, since the vertical force is applied by a weight, the vertical force is constant during the test. Therefore, in order to obtain the failure envelope, perform a shear test many times using weights of different weights.
At this time, the relationship between the normal force and the shear force must be plotted on orthogonal coordinates and then determined by connecting them, which has drawbacks such as requiring a great deal of time and effort.

SUMMARY OF THE INVENTION An object of the present invention is to provide a shear testing device for powder and granular materials that overcomes the drawbacks of the prior art and is capable of determining the fracture envelope of a powder and granular material through a single shear test.

This invention was developed by confirming through experiments that the volume of the powder layer changes with shearing, and that when shearing is performed under a constant volume, the vertical force gradually increases or decreases. As a means of maintaining the volume and measuring changes in the vertical force, a press shaft equipped with a screw feed mechanism applies a vertical force to the powder layer, and a load cell is attached to the tip of the press shaft to measure the vertical force. It is configured so that it can be directly measured.

Hereinafter, the present invention will be described in detail according to embodiments shown in the drawings. FIG. 2 is a partially cutaway front view of a powder shear test device showing an embodiment of the present invention.

The base 1, a pair of stanchions 17, and a cross beam 18 are fixed to each other to form a rigid frame structure, and the stanchion 17 and a pair of slidable thrust bearings 2 are connected to each other.
One end (lower end) of the press shaft 19 is connected perpendicularly to the center of the arm 21 that connects and fixes the press shafts 2 to 2. One end (lower end) of the press shaft 19 is rotatably but immovably connected in the axial direction. A handle 20 is screwed onto a portion of the press shaft 19 that protrudes from the cross beam 18, and the handle 20 is supported by the support cylinder 23 on the cross beam 18 so as to be rotatable but immovable in the axial direction. Therefore, the handle 20
By rotating the arm 21, the arm 21 can be raised and lowered.

The inner peripheral wall extension member 13, the outer peripheral wall extension member 12, and the seat 6, which are arranged coaxially with the press shaft 19, are fixed to the base 1, and a sliding metal 14 is attached to the lower half of the inner peripheral wall extension member 13. There is. A plurality of ball bearings 5 are mounted on the upper surface of the pedestal 6, and a rotary pedestal 4 having an annular recess opening on the upper surface is mounted via the bearings 5. The inner and outer diameters of the recessed portion of the rotary pedestal 4 are equal to the inner circumferential diameters of the outer circumferential wall of the inner circumferential wall extension member 13 and the inner circumferential diameter of the outer circumferential wall extension member 12, respectively.
3. There is a small gap between the outer peripheral wall extension member 12 and the upper surface of the rotating base 4. Further, the inner circumferential surface of the rotating base 4 is rotatably attached to a sliding metal 14. An annular rack 16 is fixed to the outer edge of the rotating base 4, and the pinion 1 is connected to the pinion 1 through a drive device 7, a bar 8, and a rotational dynamometer 9 as a drive power measuring device.
As a result of power being transmitted to the rack 16 by the rack 5, the rotary base 4 is structured to rotate horizontally.

A load cell 2 is installed at the lower end of the press shaft 19.
A lid 2 is attached to the lower end of the load cell 24 to fit into an annular gap formed by the inner peripheral wall extension member 13 and the outer peripheral wall extension member 12.

In such a configuration, a powder layer 3 is formed by filling a space surrounded by the rotating base 4, the inner circumferential wall extension member 13, the outer circumferential wall extension member 12, and the lid 2 with powder. In this state, the handle 20 is rotated to lower the press shaft 19, arm 21, load cell 24, and lid 2, and the powder layer 3 is compacted until it reaches a constant volume. Next, when the rotary base 4 is rotated by the drive device 7, the powder layer 3 is sheared under a constant volume.

During the shear test, the load cell 24 and rotational dynamometer 9
The output of
Determine the fracture envelope of the powder by recording with a Y plotter or the like. That is, according to experiments conducted by the inventors, the change in normal force associated with shearing of a powder layer generally increases in the case of granules and decreases in the case of powder. If the normal force and shear force during a shear test are drawn as a continuous line on a rectangular coordinate plane using the shear test device according to the present invention that utilizes this characteristic, this continuous line is the fracture envelope of the powder or granular material.

As described above, according to this embodiment, the fracture envelope of a powder or granular material can be determined by a single shear test.

Further, the distance between the arm 21 and the base 1 can be accurately measured using a dial gauge or the like, and thereby the thickness of the powder layer 3 can also be accurately determined. Therefore, it is possible to perform a shear test after accurately setting the volume, apparent specific gravity, porosity, etc. of the powder layer 3, which provides excellent reproducibility and reliable mechanical properties of the powder and granule material. Physical property values can be determined.

Further, inner and outer peripheral wall extension members 13 and 12 are provided, and a minute gap is formed between the lower surface of the inner and outer peripheral wall extension members 13 and 12 and the upper surface of the rotating base 4, and a fine gap is formed between the lower surface of the inner and outer peripheral wall extension members 13 and 12, and the powder layer The shear 3 is always generated in this minute gap, and the thickness of the powder layer 3 can be determined accurately as described above, so from this point of view, it is possible to improve the test accuracy and reproducibility. You can find the value.

As described above, according to the shear test device for powder and granular materials according to the present invention, the fracture envelope of the powder and granular materials can be determined in just one shear test, and the mechanical properties of the powder and granular materials can be determined in an extremely short time. It can be determined by time.

[Brief explanation of the drawing]

FIG. 1 is a fragmented sectional view showing a conventional shear test device, and FIG. 2 is a fragmented sectional view showing an embodiment of the present invention. 2... Lid, 3... Powder layer, 4... Rotating pedestal,
7... Drive device, 9... Rotary dynamometer as a drive power measuring device, 12... Outer peripheral wall extension member, 13...
...Inner peripheral wall extension member, 19...Press shaft, 2
4...Load cell.

Claims (1)

[Scope of utility model registration request] a rotary pedestal having an annular recess opening on the upper surface; an inner and outer peripheral wall extension member extending upwardly the inner and outer peripheral walls of the recess; and a lid that fits into the annular gap formed by the inner and outer peripheral wall extension members; The rotating pedestal,
A powder layer filled in a space surrounded by the outer peripheral wall extension member and the lid, a driving device for the rotary base, and a driving power measuring device for measuring the driving power by the driving device, and the lid has a screw feeding mechanism. A shear test device for powder and granular material, characterized in that it is attached via a load cell to the lower end of a breath shaft that is raised and lowered by a mechanism.