CH618789A5 - Appliance for measuring the flow properties of granular substances and substance mixtures. - Google Patents

Description

The purpose of the present invention is to provide a device with which these flow properties can be determined quickly and precisely. After knowing the measurement results, it is then possible to optimize these flow properties by changing the physical properties, for example the grain size and / or the moisture content of the substances or substance mixtures, until the amount flowing out of an opening per unit of time remains constant. This is particularly important for the automatic tableting of granular substances or mixtures of substances.

This purpose is achieved with the device defined in claim 1.

An exemplary embodiment of the invention is explained below with reference to the drawing.

The discontinuous flow values of a poorly tablettable, multi-component granulate (referred to in the table with R. T.) were examined in the following way. 100 g of granules were filled into the device and the amount of granules falling through the opening having a diameter of 10 mm was weighed with mg accuracy, with the opening increasing by 0.1 s in each case. In the same way, 4 granules were examined, which consisted of 97% milk sugar, 2% gelatin and 1% magnesium stearate and differed in the way they were produced. The following values were obtained:

Material quantities of different granules that have flowed through within different periods of time

Granu

Time (s)

lat

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

R.T.

1.25

2.45

3.2

4.5

5.5

6.5

7.4

8.3

8.7

1

1.6

2.9

4.1

5.3

6.75

7.8

9.0

10.3

-

2nd

1.5

2.6

3.7

4.8

5.9

7.0

8.15

9.25

-

-

3rd

1.6

2.8

4.0

5.2

6.4

7.6

8.8

10.0

-

-

4th

1.75

3.1

4.4

5.7

7.1

8.4

9.75

11.15

-

-

Note: Each value is the average of 10-22 measurements. The spread is ± 0.14-0.23%.

Through mathematical analysis of the values it can be determined For the easily tablettable milk sugar granules (1-4)

that the b0 belonging to the individual time periods t (s) results in the following general equation: the amount of material m (g) that has passed through in the case of the granules which are difficult to tablettate can be described by the following equation = a * t + b:

The values of the natural constants a and b, the Schüttwin-m = a • t1M b5 kel of the powder flowed out as well as those with the ASTM-

Method (E. Pandula, G. Takâcs: Ipari gyógyszerészet, Medi-wherein a and n are natural constants and the values a = 1.02 cina Budapest 1964, p. 624) have certain fluidity values and n = 1.11. are summarized in the following table.

3rd

618 789

Values of the well tablettable granules

Natural constants a b

Angle of repose ASTM (g / s)

1

12.3

0.4

42.9 °

12.4

2nd

11.0

0.4

44.7 °

12.1

3rd

12.0

0.4

42.3 °

12.4

4th

13.3

0.4

42.5 °

12.5

From the table it can be seen that the introduced function constant a gives a better characteristic of the fluidity than is the case with the other methods.

Since, in operational practice, a certain amount of powder has to fall through an opening of a given cross-section and a time period that can only be set on the machine within narrow limits is available, the values can be used to determine which of the parameters that can be regulated by setting the machine the given powder is suitable for the respective machine operation (tableting, packaging, etc.).

According to one embodiment, the measurements are carried out with a device consisting of an exchangeable funnel and an exchangeable opening. The opening is covered by a corresponding closing part, the opening and closing, that is to say the pouring out of the examined powder, takes place by means of electrical and mechanical elements arranged in an appropriate order.

According to another embodiment, the powder quantities flowing out of a given funnel through a given opening within different time units are measured gravimetrically. In another variant, the flow rate of a selected quantity of powder from a given funnel through a given opening is measured with the same arrangement. In both cases, the height of the conical funnel and the cross section of the opening can be chosen as desired.

The advantage of the invention is that it also influences the flow properties of the various properties of the powder, such as grain size distribution,

Composition, moisture content, additives, etc., can be examined.

Two preferred embodiments of the device are shown in FIGS. 1 and 2.

The device shown in FIG. 1 consists of an electronic control unit I, an electronic evaluation unit III, actuators IV and V activated by the unit II, a closing element VII controlled by the actuators and an opening which can be opened and closed therewith VIII. According to a preferred variant of this embodiment, the opening VIII is provided with a sensor IX which sends an end signal to the evaluation unit III.

The embodiment of the device according to the invention shown in FIG. 2 consists of a unit 1 receiving and transforming the signal for manual opening, a unit 2 receiving and transforming the signal for manual closing, and a unit 3 receiving and transforming the signal for changing operations logic circuit 4, a time control element 5, a display control element 6, display unit 7, counter 8, an opening control element 9, a closing control element 10, a circuit breaker 11 connected to the logic circuit and a circuit breaker connected to the time control element 12.

The invention is illustrated by the following example.

30th

35

40

example

Granules with the following composition:

Active ingredient

Magnesium stearate

Polyvidonium

talc

Potato starch lactose

28% 2% 3% 3% 30% 34%

is produced with three different water contents and examined in the granulate exponer. This is used to measure the quantities of the granules which only differ in terms of their water content and are otherwise completely identical. The following values are obtained:

H2O content

0.1

0.2

0.3

0.4

Opening times (s) 0.5 0.6 0.7

0.8

0.9

1.0

5.5%

0.93

1.52

1.95

2.35

2.70 3.15 3.40

3.75

2.34%

0.93

1.62

2.20

2.84

3.35 3.82 4.32

4.81

-

-

1.2%

1.35

2.42

3.10

4.40

5.21 6.15 7.02

7.92

8.77

9.52

Note: The standard deviation of the measured values is ± 2.5%

Mathematical analysis of the measured values 55 shows that the relationship between the amount of granules m (g) falling through and the time t (s) can be represented by the equation m = a-t1 / b.

(1)

With different moisture content (1.2-5.5% H2O), the water content is included in the natural constants in the following way:

(9)

Ii + c LH2O% J

60 By inserting the expressions (2) and (3) in (1) we obtain:

I t b = a- (H2Ö%) n m «

ß

[HP0

+ 0 "

«L'HoO #] n

In the case examined, the natural constants have the following (2) values: a = 1.1; β = 0.204; C = 2.65; n = 0.189.

2 sheets of drawings

Claims (2)

618789 PATENT CLAIMS 1. Device for measuring the flow properties of granular substances and substance mixtures, characterized by the following components: a container with an outlet opening (VIII) and with a closing element (VII) for opening and closing this opening, actuators (IV, V) for actuating the Closing element (VII), an electronic unit (II) for actuating the actuators, an electrical evaluator (III) for evaluating measured variables, a control unit (I) for controlling the electronic unit (II) and for outputting signals which indicate the state of the device, whereby this control unit (I) has a first converter (1) which responds to manually triggered signals for the electromechanical opening of the outlet opening by means of the closing element (VII), a second converter (2) which responds to manually triggered signals for the electromechanical Closing the outlet opening by means of the closing element (VII), a third to manually triggered signals responsive converter (3) for changing the operating mode of the device, and having a logic circuit (4), the input of which is connected to the three converters (1, 2, 3), and wherein the evaluator (III) has a control means (6) having a display unit (7) and a counter (8) connected to it, and wherein the electronic unit (II) for the actuators has a first control element (9) for opening and a second control element (10) for closing the outlet opening, which two are connected to the time control element (5) and each influence a circuit breaker (11 or 12) for actuating the actuators (IV or V). 2. Device according to claim 1, characterized by a in the outlet opening (VIII) arranged sensor (IX) for sending signals to the evaluator (III). 10th 20th 25th Numerous publications have dealt with the research of the flow properties of granular substances or mixtures of substances. Most recently, TM Jones and N. Pilpel (J. 40 Pharmacol. 18, 429-442 [1966]) have investigated the effect of the grain size distribution on QF Danish and EL Parroth (J. Pharm. Sei. 60,548-554 [1971]) measured the mass velocity (g * s-1) of the outflowing powder with different openings and variable height of the powder column to be measured. K. Kurihara and I. Ichikawa (Chem. Pharm. Bull. 21 [2], 394-403 [1973]) found mathematical relationships between the flow velocity, the relative cross-section and the grain size. The previously known devices do not meet today's requirements for a quick and precise determination of the flow properties, for example for the production of pharmaceutical tablets. Furthermore, no apparatuses are known so far which enable an automatic or semi-automatic measurement of these flow properties.