ASTM D6128 Test Fixture

Description

ASTM D6128- Standard Test Method for Shear Testing of Bulk Solids Using the Jenike Shear Cell

 

ASTM D6128  covers the apparatus and procedures for measuring the cohesive strength of bulk solids during both continuous flow and after storage at rest.

In addition, measurements of internal friction, bulk density, and wall friction on various wall surfaces are included.

The most common use of this information is in the design of storage bins and hoppers to prevent flow stoppages due to arching and ratholing, including the slope

and smoothness of hopper walls to provide mass flow.

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ASTM D6128  / Significance and Use

Reliable, controlled flow of bulk solids from bins and hoppers is essential in almost every industrial facility.

Unfortunately, flow stoppages due to arching and ratholing are common.

Additional problems include uncontrolled flow (flooding) of powders, segregation of particle mixtures, useable capacity which is significantly less than design

capacity,caking and spoilage of bulk solids in stagnant zones, and structural failures.

By measuring the flow properties of bulk solids, and designing bins and hoppers based on these flow properties, most flow problems can be prevented or eliminated.

For bulk solids with a significant percentage of particles (typically, one third or more) finer than about 6 mm (1⁄4 in.), the cohesive strength is governed by the fines

(-6-mm fraction).

For such bulk solids, cohesive strength and wall friction tests may be performed on the fine fraction only.

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ASTM D6128  / Apparatus

The Jenike shear cell is shown in Figs. 1-3.

It consists of a base (1), shear ring (2), and shear lid (3), the latter having a bracket (4) and pin (5).

Before shear, the ring is placed in an offset position and a vertical force F v is applied to the lid and hence to the particulate solid within the cell by means of

a weight hanger (6) and weights (7).

A horizontal force is applied to the bracket by a mechanically driven measuring stem.

It is especially important that the shear force measuring stem acts on the bracket in the shear plane (plane between base and shear ring) and not above or below

this plane.

The standard size Jenike shear cell is made from aluminum or stainless steel, and a smaller 63-mm diameter cell made from stainless steel is also available.

*** Before conducting ASTM D6128 , it is important to read the entire specification. Standards can be obtained from appropriate standard authorities.

 

***PARSROS  offers several types of grips and fixtures which will enable you to perform a variety of tests

  that are accurate and repeatable.