DE3314202A1 - Apparatus for determining the flow properties of solid bulk materials - Google Patents

Abstract

A description is given of an apparatus for determining the flow properties of solid bulk materials consisting of an elongated rectangular sample container (1), at least the front wall of which is transparent, with a skimmer (2) for transferring excess material to the overflow (3), which feeds into the collecting container (7), and two parallel slide bars (4 and 5), which work in opposite directions and are driven by the threaded spindle (6), with the scale (9) for reading off the gap width above the collecting container (7), and a mobile protractor (8) in front of the transparent front wall of the sample container (1) for reading off the natural angle of repose. The flow number obtained is a fictitious variable which depends both on the bulk material and on the measuring apparatus. <IMAGE>

Description

33H202

Device for · determination of the flow properties of solid debris

The invention relates to the device of claim.

In many branches of industry as well as in pharmaceutical In industry, disperse solids such as powder or granulates are processed. Because powders and granules are not like solids and liquids are continuous masses but collections of independent particles, a special theological aspect occurs Behavior that leads to technical difficulties in the dosage accuracy of the active ingredient content and the weight single-dose dosage forms such as tablets, coated tablets and capsules.

Difficulties arise in particular when powders are highly cohesive.

In the past there has been no lack of measuring methods and devices for determining the flow behavior, in particular the angle of repose and the flow velocity develop au. (In the context of the present Invention understood the angle obtained by the free surface of a resting, under specified conditions Piles of powder against the horizontal. "The Storage and Recovery of Particulate Solids ", Appendix D; A Report of a Working Party of The Institution of Chemical Engineers, edited by J.C. Richards (1966).

Flow material is allowed to run out from a constant height through a funnel until the tip of the cone just does

COPY

33H2Ü2

Has reached the end of the funnel (pouring angle).

The good flows

from a funnel onto a flat, raised circular plate until the material flows over the edge of the plate.

The material is poured into a cylinder, which is the same on a second, solid or hollow cylinder Diameter is located. By carefully lifting the upper cylinder, a cone is formed on the base.

The goods are in a larger container with a built-in circular platform. As soon as the good is through an opening in the lower part of the container flows out, a cone remains on the platform.

The good is in an expediently transparent Container with a horizontal bottom. If the material runs out through an opening in the floor, it remains a residue in the container whose angle of inclination to Horizontal is determined. The container and the outlet opening can either be rectangular (2-dimensional Outflow angle) or have a round shape (3-dimensional ler outflow angle).

However, the known devices have the disadvantage that their operation is cumbersome and a larger number making measurements is therefore very time-consuming.

The object of the present invention was to provide a device that is easy to use, a high one Throughput of samples allowed and still shows a high reproducibility of the measured values.

COPY

The task according to the invention was achieved with the

according to the device solved, which consists of a stretched,;

rectangular sample container (l) , in which the purpose-;

at least the front wall is moderately transparent j

and with a scraper (2) for transferring over- _;

waste material in the overflow (3) »the in the j

Collecting container (7) leads. On the horizontal floor '.

of the sample container (l) there are two opposing j

Parallel slides operated via the threaded spindle (6) _: (4 and 5) with the scale (9) i which open to a gap and allow the sample to flow into the collecting container (7), the width of the gap being read on the scale (9)

can be. <

The angle j in front of the transparent front wall

knife (8) is used to read the slope angle. To the j

Leveling the device are used by adjustable feet and a j

Dragon-fly. A schematic representation of the invention [

MAESSEN device is shown in FIG. j

To determine the flow properties, refer to the sample |

container (l) a conical filling funnel that!

Sample poured onto the incline of the filling funnel and taken from:

there slid into the sample container (l) and with
the scraper (2) brought to a defined height. then
the threaded spindle (6) is turned on the rotary knob until
the slides (k and 5) open and the sample flows out until the tear-off edge has reached the surface. Then read the angle with the protractor (8).

It has proven to be useful as a material constant
to use a fictitious quantity to characterize the flow properties. This quantity was called the flow number

COPY

1 / ι 1

14 / _ J ζ

and was defined as follows:

Flow index = gap width (cm) χ depth of device (cm) χ Bosch: η ^; - angle (Degree).

A high flow number indicates poor flow properties of the bulk material, while small flow numbers indicate good flow properties.

example

. Consisting A. With a sample of placebo Graiiulat of 75 wt -% lactose, 20, ei% cornstarch, 2.5% polyvinylpyrrolidone, 1, Ί% talc and 0.3% of magnesium stearate, the following measurements are obtained:

Gap width
(cm) Approach angle
(Degree) to the right Mi. divided Flow number 0.18 Left 52 5't, 5 39.2 0.20 57 50 53.0 k2, k 0.10 56 50 53.0 33.9 0.18 56 51 53.5 38.5 0.16 56 51 53.5 3 ^, 2 56

The mean flow number is 37.6.

COPY

B. With a sample of a placebo powder molding compound consisting of 6 3.8% by weight lactose, 29.8 % raikro- ^v crystalline cellulose, 5.9 % corn starch and 0.5 % magnesium stearate, the following measurement results are obtained :

Gap width Approach angle Left to the right Average Flow number (cm) (Degree) 65 70 67.5 65 60 62.5 1.89 82 85 83.5 510.3 1.90 73 73 73 475.0 1.72 87 82 84.5 574.5 1.46 70 62 66 426.3 2.00 676.0 1.40 369.6

The mean flow number is 505.

The device depth is 4.0 cm for both measurements.

COPY

Claims (1)

33U202 JS Claim Device for determining the flow properties of solid bulk materials, consisting of an elongated, rectangular sample container (1), at least the front wall being transparent, with a scraper (2) for transferring excess material into the overflow (3; 3) which flows into the collecting container (7 ) and two counter-rotating parallel slides (4 and 5) operated via the threaded spindle (6) with the scale (9) for reading the gap width above the collecting container (7) and a • ί * · sliding protractor (8) in front of the transparent front wall d'es sample container (l) for reading the Guidelines. COPY