Jr Johanson, Inc.

Kerry D Johanson

Jerry R Johanson

Brian D Cox

An instrument for measuring certain physical properties of a sample of particulate material so that the flow characteristics of the material can be determined includes an improved compaction assembly having an upper piston that is surrounded by a retractable sleeve and further includes an improved test cell having cylindrical walls, having a failure outlet smaller than the diameter of the failure piston, and having a false bottom that can easily be removed from beneath a sample of compacted material to permit the failure portion of the test to be carried out. The tester can be used for determining the confined yield strength of the material, its bulk density, and its permeability.

Flow-no-flow tester

An improved flow-no-flow tester has two major advantages over its predecessor. First, it eliminates the need to invert the test cell after the compaction phase, thereby eliminating the possibility that failure of the compacted sample will occur before the failure load-measuring portion of the test can be done. Second, the improved tester determines the compaction load by measuring the force exerted by the sample against an upper piston, while a compressive force is applied to the sample by a lower piston. This results in greater accuracy than was obtained in the predecessor wherein the compaction load was taken to be the force applied to the compressing piston and which was in error due to the forces of friction and particle binding on the piston as it advanced against the sample. In addition, the improved tester minimizes the potential of particle binding during the failure portion of the test. These advantages result from the structure of the tester, in which the test cell is closed at its bottom by a lower piston that is used for applying the compaction load and that is closed at its upper end by an upper piston against which the sample is pushed in the compaction phase and which is used subsequently for applying a downward failure load. The tester also permits the failure load to be applied at various rates so that the viscous properties of bulk solids and the pseudo strength of fine powders can be measured.

Apparatus and a test method for bench scale determination of whether a particulate material will flow under the action of gravity alone from an outlet in the bottom of a container. The apparatus includes a test cell having inclined conical side walls, and that is closed at its larger end by a plug having an inwardly-facing surface that is concave and conforms to a coaxial cone. In this way, cylindrical surfaces are avoided, and the shape of the space within the test cell offers minimal interference with the plastic stress field of the material. This testing method includes the novel step of inverting the test cell after consolidation of the test material but prior to application of the failure load.

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Atascadero, CA, United States of America

Kerry D Johanson