FI57701B - REPRESENTATIVE PROCEDURE OF THE PARTICULAR SAO ATT REPRESENTATIVE PROV ERHAOLLES - Google Patents

Description

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Republic of South Africa-South Africa (ZA) 75/0251 (71) De Beers Industrial Diamond Division Limited, 8th. Floor, ^ 5 Main Street, Johannesburg, South Africa-South Africa (ZA) (72) Charlie Maurice Levitt, Johannesburg, Samuel Chatterley, Florida Lake, Transvaal, South Africa-South Africa (ZA) (7 * 0 The present invention relates to an apparatus for mixing finely divided material and for obtaining representative sample fractions from a mixture. Oy Jalo Ant-Wuorinen Ab (5 * 0 Apparatus for dividing a partial feed into representative samples - The present invention relates to an apparatus for mixing fine material and obtaining representative sample fractions from a mixture.

The most common, but not necessarily the most optimal method for mixing a finely divided substance consisting of ingredients of different sizes or different densities or mixtures of different substances is to use a mixing drum into which the substance is fed. The mixing drum most preferably makes an 8-digit movement, which is obtained by rotating the mixer about a horizontal axis and swinging it around a moving "" axis perpendicular to the axis of rotation. To achieve good mixing, the mixer must be operated for several hours. Fragile particles may disintegrate during mixing.

Numerous methods and apparatus are used to obtain samples from a batch of fines. In all cases, the aim is to obtain a representative sample and, in some cases, to obtain an "exact sample" of the substance, the "exact sample" being defined as the "exact weight of the representative sample". The simplest sampling method is "spooning". Accurate weights can be obtained with this method but the samples are by no means representative. Similarly, for very large batches, a sampling method in which the substance is manually stacked into a soup, a heap is applied, the applied heap is divided into quarters, two quarters are removed, and the procedure is repeated for the remainder does not produce representative samples.

There are many sample dispensers in use in the industry. One commonly used device comprises an inclined plate from which a plurality of wedges protrude.

The wedges divide the partial stream flowing along the plate into fractions, which are removed through a hole in the plate at the root of the wedges. Ordinary sample dividers divide the substance into sixteenths. Smaller fractions, each with powers of 16, are obtained by passing the material through the apparatus again.

Sample dividers, also known as gutter dividers, divide the sample into two parts. Re-derivation yields samples corresponding to approximately quarters, eighths, etc., and by combining it is theoretically possible to obtain an "exact _ sample". In practice, exact weights can never be obtained and the samples are not fully representative. Furthermore, the device cannot be used uncomplicated, for example, to provide 100 accurate samples for testing by as many customers. It is also not possible to carry out continuous sampling. Finally, the device has the considerable disadvantage that its use is frustrating.

Sample distribution and reduction devices are not suitable for mixing fines because they require a lot of time in use. Nor do they provide a two-dimensional homogeneous distribution of matter.

It is an object of the invention to provide an apparatus for dividing a particle feed into representative samples which is simple and quick to use and which comprises a housing delimiting a closed space through which the flow of particles can pass under gravity and a plurality of deflection members mounted in the housing. wherein the deflection members form a plurality of vertically spaced layers, each of which includes a plurality of deflection members spaced apart in a horizontal plane extending over a horizontal horizontal cross-section of the housing.

According to the invention, there is provided an apparatus for distributing a partial flow, which is characterized in that means are arranged downstream of the deflection means for collecting at least some of the particles passing through the deflection means.

The deflection members are preferably rods that are substantially parallel to each other. The spaces between the bars have been made sufficiently large so that groups of two or more parts do not wedge into the spaces between the bars. A suitable spacing between adjacent rods is approximately 3-30 times the size of the largest particles. Preferably, the spacing of adjacent rods is 3-10 times the size of the largest particles.

According to the invention, the bars of some of the horizontal layers form an angle with respect to the remaining bars. The recommended angle is 90 °. This angle ensures that the mixed material is homogeneous in the plane, i.e. in two mutually perpendicular dimensions.

The layers are suitably mounted in two groups of layers, the bars in each group being substantially parallel to each other and forming an angle with the bars in the other group.

The invention will also be illustrated by the accompanying drawing, in which Figure 1 is a perspective view of a preferred embodiment of a device according to the invention, Figure 2 is an enlarged side view of a portion of the device of Figure 1, and "Figure 3 is a perspective view of a container having a plurality of logs or" exact samples ". .

The drawing shows an apparatus 10 for mixing a fines in two dimensions to obtain a homogeneous stream or mixture of materials. The apparatus 10 comprises two groups of rods 12 and 14, each of which consists of a plurality of rows of rods 15 in a row, the rods of the second group being substantially perpendicular to the rods of the second group. The rods 15 of each group form layers 16 which are spaced vertically apart (see Figure 2). The rods are spaced apart in two overlapping horizontal layers such that each rod is vertically below and substantially midway between the two rods of the previous layer. The rods are enclosed in a rectangular housing 20 with a reservoir 22 below the lowest layer of the rods. The rods can be mounted at any angle to each other other than at a right angle, for example 120 °. Parallel bars also do not need to be arranged in groups of layers but can be installed alternately. That is, in each successive tan layer, the bars may be mounted perpendicularly or obliquely to the bars of the previous layer.

Ten bars 15 are mounted on each second horizontal layer 16, with 9 bars between the layers between them. Each layer group 12 and 14 has 19 horizontal layers. The housing 20 supports the rods 15.

The space between the bars, both vertically and horizontally, should be sufficient to prevent two or more particles from getting stuck between the two bars. The gap successfully used is three times the diameter of most of the particle, measured between the surfaces of the rods 15. In the embodiment in which the diamond part or diamonds were mixed with the resin particles, each rod had a diameter of about 6.3 mm, a length of 30 cm and a distance of about 1.9 cm between the longitudinal axes of the parallel bars. An opening of about 1.3 cm was formed between the long ends of the walls and the bars.

The cross-section of the bars is preferably circular, as a result of which the part impinging on the bar deviates from its direction substantially randomly, for example a typical passageway 18 is shown on the left side of Fig. 2. Other cross-sectional shapes of the bar may be used provided that the shape does not affect the randomness of the passage of the particle as it passes through the layer groups 12 and 14.

In Figure 3, inside the vessel 22, round vessels 24 and rectangular sample vessels 26 are placed. Vessels of any number or size may be used. 100 square sample vessels can be used to obtain 100 exact samples.

In practice, the material is poured through a funnel in the middle of the layer groups, above them, and collected in a similar container 10 in the tank 22 to obtain a premix of the material. The contents of the containers are then in turn poured through the layers and assembled from the bottom of the layers as desired.

As they pass through the layers, the particles collide with the rods 15 and occasionally deviate from their path. At the same time, the particles mix with each other to achieve a homogeneous distribution. As shown in Figure 2, as the substance falls through the first layer group, it spreads in the manner of an expanding prism and forms a homogeneous mixture, for example in the X-direction. This mixture then spreads in the Y-direction at right angles to the X-direction as it passes through the second group of layers and leaves as a homogeneous partial rainfall which spreads over substantially the entire area of the vessel 22.

In the above embodiment, each group has 19 horizontal layers. The number of layers may be as small as 10 or there may be a thousand depending on various factors such as the diameters of the bars 15 and the spaces between them; the nature and size of the components to be mixed and the degree of mixing desired. Increasing the number of layers has little effect— ”“ on the time required to mix the finely divided material.

Degradation of brittle components, such as diamond particles, is minimized by using the apparatus of the invention. This is because the parts are substantially only affected by gravity; and the distance a particle falls into the rods between collisions is small, so the forces acting in the collision are small.

Specific embodiments of the hardware.

1. Dividing or reducing the sample.

This can be achieved with a single pass through the device. For example, a 4 g sample is obtained from a 4000 g batch using one 1 cm x 1 cm container in a device with a 33 x 33 cm bottom.

2. Accurate sampling.

This can be achieved with a series of containers, each sized to contain a certain amount of substance, for example 240, 10, 5, 2, 1 g.

The actual weights in the containers after one pass can be determined and combined to give an "exact" weight. For greater accuracy, the contents of the selected vessel can be re-passed through the device.

3. Large number of samples from a given lot.

This can be achieved by dividing the container into a corresponding number of containers, for example 5, 25, 100, 1000, etc.

4. Continuous sampling.

This can be achieved by using a pipe with a certain cross-sectional area, which pipe is placed vertically below the layers. Such a procedure is not applicable to standard sample dispensers.

Claims (5)

57701 6 An apparatus for dividing a particle feed into representative samples, the apparatus comprising a housing (20) defining an enclosed space through which the flow of particles can pass under gravity and a plurality of deflection members (15) mounted in the housing to deflect particles in the flow, the deflection means (15) forming a plurality of vertically spaced layers (16), each of which includes a plurality of deflection members (15) spaced apart horizontally extending over a horizontal horizontal cross-section of the housing, characterized in that members (22, 24) are arranged downstream of the deflection members (15), 26. for collecting at least a portion of the particles passing through the deflection means. Apparatus according to claim 1, characterized in that the deflection members (15) are rods and in that the rods (15) of the adjacent layers are displaced laterally relative to each other so that, when projected onto a plane, each rod is between two rods of the adjacent layer. Apparatus according to claim 2, characterized in that the bars (15) of some layers (16) form an angle with the bars of the other layers. Apparatus according to any one of claims 1 to 3, characterized in that the particle collecting means comprise a container (22) and at least one part of an upwardly open container (24, 26) for collecting particles accumulating in the container when the particles are lowered through the deflection members (15). . Apparatus according to any one of claims 1 to 3, characterized in that the particle collecting means comprise a tube having a diameter smaller than the cross-section of the housing (20) below the deflection members for continuously collecting a part of the partial flow through the deflection members.