ISO 4324:1977 pdf download – Surface active agents – Powders and granules – Measurement of the angle of repose
5.1.2 Agitator, comprising two rods placed opposite one another along the whole length of the interior Wall of the funnel (5.1 .l), and extending into the Stern; these rods should be capable of being turned easily by means of a handle.
5.1 .3 Base-plate, of minimum length 220 mm and minimum width 158 mm. The base-plate shall be completely rigid and shall have a polished surface or be engraved with concentric circles of diameters of from 1 0 to 1 00 mm, the centres of which shall be coaxial with the axis of the funnel.
5.1.4 Transparent plastic vessel, of minimum diameter 1 00 mm and minimum height 25 mm, placed 75 mm below the lower end of the funnel (5.1.1 ). Its internal surface shall be slightly rough. lt shall be positioned on the base- plate (5.1.3) in such a way that the centre of the vessel and the axis of the funnel coincide, the centring being facilitated by the graduation of the concentric circles on the base-plate.
5.1.5 Funnel support, fixed and positioned so that the axis of the funnel (5.1 .l) is the vertical line passing through the centre of the concentric circles engraved on the base- plate (5.1 .3). 5.1.6 Supporting rod, comprising a scale graduated in millimetres from 0 to 1 00, starting from the base-plate (5.1 .3). A rod ,integral with a horizontal slide moves on this scale, allowing the height of the cone to be measured. The whole apparatus shall be protected against Vibration.
7.1 Preparation of sample and test portion
If the laboratory sample has formed agglomerates after a prolonged period of storage, it may still be examined if it regains the fluid state after the vessel containing it has been inverted.
Take 150 ml of the laboratory sample with the graduated measuring cylinder (5.2).
7.2 Determination
Carry out the measurements in one of the standard atmospheres defined in ISO 554.
Place the test portion in the funnel (5.1.1)， having previously blocked the stem. Unblock the stem and allow the powder to flow through, slowly agitating it using the agitator (5.1 .2).
NOTES
1 The agitator is not always required, but to achieve the specified reproducibility of the tests, the agitation process should always be included .
2 In the case of sticky products, it may be necessary to complate the discharge by careful use of a spatula.
Two minutes after the flow has ceased, measure the height of the powder cone. Carry out a minimum of five tests on different portions of
the laboratory sample.