Device for filling bulk material

Abstract

Device for filling bulk material (28), in particular powder material, with a downpipe (12) which has an inlet opening (14) at one end and an outlet opening (16) for the bulk material (28) at the other end, with a tubular film (18) lining the downpipe (12), which is fastened to the downpipe (12) at its open ends and delimits an intermediate space (22) with the downpipe (12), and with a compressed air device for introducing compressed air into the intermediate space (22) via a ventilation opening (24) in the downpipe (12) and for discharging the compressed air from the intermediate space (22) via a ventilation opening (26) in the downpipe (12).

Description

[0001] The invention relates to a device for filling bulk material.

[0002] Bulk material, especially powder material, is typically filled via a downpipe. The bulk material is poured into the downpipe through an inlet opening. Due to its essentially vertical or steeply inclined orientation, it falls downwards. It exits through an outlet opening of the downpipe and is then poured into containers, packaging, a dosing device, or a production facility. The problem with this approach is that powder mixtures can partially separate upon impact with a substrate after exiting the downpipe, resulting in batches of the powder mixture no longer containing the correct mixing ratio of the powder components.

[0003] It is therefore an object of the invention to develop a device for filling bulk material in which the risk of demixing of the bulk material is reduced.

[0004] This object is achieved according to the invention by a device having the features of claim 1. Advantageous developments of the invention are the subject of the dependent claims.

[0005] The invention is based on the idea of ​​slowing down the fall of the bulk material through the downpipe by forcing the bulk material to force its own way through the tubular film that has previously been compressed using compressed air. The film is compressed by the compressed air so that its clear width is reduced to zero or close to zero. If the air pressure in the space between the bulk material and the downpipe is reduced after the bulk material has been poured into the downpipe, in particular to ambient pressure, the internal pressure of the bulk material can increase the clear width of the film tube, causing the bulk material to slide downwards through the downpipe. The applicant has discovered that with a suitable choice of film, the speed of the bulk material in the downpipe can be reduced to just a few centimeters per second, thus counteracting the demixing of a powder mixture upon impact after it emerges from the downpipe's outlet opening.It is preferred that the film be made of polyethylene (PE) or another polymer. This can be pure polyethylene (LDPE or HDPE), polyethylene with additives, or a material blend whose main component is polyethylene. It can be single-layer or multi-layer. Its thickness, which largely determines the rigidity and deformability of the film tube, is preferably between 0.08 mm and 0.15 mm, with a thickness of approximately 0.1 mm being preferred.

[0006] A control device is expediently provided for controlling the inlet and / or outlet of compressed air, preferably at a pressure of 1 bar to 1.5 bar, into and out of the intermediate space. In particular, the control device can be used to specifically reduce the excess pressure in the intermediate space based on the above-mentioned values ​​in order to keep the falling speed of the bulk material in the downpipe low. For better control of the air pressure in the intermediate space, at least one pressure sensor is expediently used. This sensor measures the air pressure in the intermediate space and uses the measured values ​​of this pressure sensor to control the inlet and / or outlet of compressed air.

[0007] The film is conveniently attached to the downpipe by means of flanges placed on the downpipe. The film is preferably clamped at the relevant end between the downpipe and the respective flange. Tri-clamp flanges are preferred for this purpose. This makes it particularly easy to replace and, in particular, without the aid of tools. A filling hopper is conveniently provided, which is connected to the downpipe and opens into the inlet opening. The filling hopper advantageously has a butterfly valve. The filling hopper can then be filled with bulk material with the butterfly valve closed, or it can be placed on the downpipe already filled. When the butterfly valve is opened, the bulk material enters the inlet of the downpipe.

[0008] Two separate openings can be provided for introducing compressed air into the gap and discharging it from the gap, i.e., a ventilation opening and a separate vent opening. However, it is preferred that the ventilation opening and vent opening coincide, so that only one opening for the compressed air needs to be provided in the downpipe.

[0009] The invention will be explained in more detail below with reference to an embodiment shown schematically in the drawing. Fig. 1 a device for filling bulk material, Fig. 2 to 6 the device according to Fig. 1 with attached filling funnel in different operating situations.

[0010] The device 10 shown in the drawing is used for filling bulk material, in particular powder mixtures. It has a downpipe 12 which, during operation, is oriented vertically or nearly vertically, with an angle of inclination relative to the horizontal of at least 80°. The downpipe 12 has an inlet opening 14 at the upper end and an outlet opening 16 at the lower end. Arranged inside the downpipe 12 is a tubular film 18 which, with its open ends in the region of the inlet opening 14 and in the region of the outlet opening 16, is connected to the downpipe 12 by means of a Tri-Clamp flange 20 in that it is clamped between the downpipe 12 and the flange 20. The film thus lines the downpipe 12 along its entire length like an inliner, so that bulk material filled into the inlet opening 14 falls through the film 18 to the outlet opening 16.

[0011] Between the wall of the downpipe 12 and the foil 18 there is a circumferential space 22, the volume of which is almost zero when the foil 18 is in contact with the wall of the downpipe 12, as in Fig. 1, Fig. 2. Compressed air with a maximum pressure of 1.5 bar can be introduced into the intermediate space 22 via a ventilation opening 24 in the downpipe 12 by means of a compressed air device (not shown in the drawing). The compressed air compresses the tubular film 18 over its entire length so that its clear width is reduced to zero or almost zero, so that no bulk material can fall through the downpipe 12. Only when the pressure in the intermediate space 22 drops as a result of the compressed air being discharged from the intermediate space 22 through a vent opening 26 can the clear width of the film 18 increase again, so that the bulk material can slip through the film 18. To feed and discharge the compressed air into and out of the intermediate space 22,From the intermediate space 22, a compressed air device (not shown in the drawing) is provided, which has, for example, a compressor connected to the ventilation opening 24 or a compressed air line connected to the ventilation opening 24 and a valve at the vent opening 26.

[0012] In Fig. 2 to 6, a filling process is shown. The bulk material 28 is shown in dark. A filling funnel 30 is placed on the downpipe 12, which opens into the inlet opening 14. Above the inlet opening 14, the filling funnel 30 is closed by a shut-off valve 32, so that initially no bulk material 28 reaches the inlet opening 14 when the filling funnel 30 is filled with bulk material 28, as shown in Fig. 2. Subsequently, the gap 22 is filled with compressed air so that the film 18 is compressed, as shown in Fig. 3. If then, as in Fig. 4, the shut-off valve 32 is opened, the bulk material 28 reaches the inlet opening 14, but is blocked in its area by the compressed film 18. Then, the ventilation opening 24 is closed and the vent opening 26 is released by opening the valve, so that the compressed air can escape from the intermediate space 22. The bulk material 28 then makes its way downward through the downpipe 12, expanding the inside diameter of the hose 18, pressing the film 18 against the wall of the downpipe 12. The film 18, due to its rigidity, offers resistance to the advance of the bulk material 28, so that the advance of the bulk material 28 in the downpipe 12 towards the outlet opening 16 occurs only slowly. Fig. Figure 6 shows how the bulk material 28 has made its way through the entire downpipe 12 and has penetrated into an extension 34, which is connected to the outlet opening 16 and can lead, for example, to a dosing device. The film 18 is again pressed over its entire length by the bulk material 28 against the wall of the downpipe 12 and again assumes the same position as in Fig. 1 and Fig. 2. Furthermore, it is possible to specifically adjust the pressure in the intermediate space 22 by means of a control device controlling the compressed air device in order to control the falling speed of the bulk material 28.

[0013] A method that can be carried out with the device according to the invention can be described as follows: 1. A method for filling bulk material, in particular powder material, with a downpipe which has an inlet opening at one end and an outlet opening for the bulk material at the other end, with a tubular film lining the downpipe, which is fastened to the downpipe at its open ends and delimits an intermediate space with the downpipe, wherein the intermediate space is filled with compressed air, preferably with a pressure of 1 bar to 1.5 bar, by means of a compressed air device via a vent opening in the downpipe until the film is compressed over at least a large part of its length, wherein the bulk material is filled into the downpipe via the inlet opening and wherein the compressed air is discharged via a vent opening in the downpipe by means of the compressed air device, so that the bulk material can expand the film and pass through the downpipe in its longitudinal direction. 2. Method according to item 1, wherein the filling of the intermediate space with compressed air and / or the discharge of the compressed air from the intermediate space are controlled by means of a control device. 3. Method according to item 2, wherein the pressure in the intermediate space is measured by means of at least one pressure sensor and wherein the filling of the intermediate space with compressed air and the discharge of the compressed air from the intermediate space is controlled as a function of the pressure measured values. 4. Method according to one of the items 1 to 3, wherein the bulk material is filled into the downpipe via a filling funnel opening into the inlet opening. 5. Method according to paragraph 4, whereby the filling hopper is filled with the bulk material and after filling the filling hopper with bulk material and after filling the intermediate space with compressed air, a shut-off valve of the filling hopper is opened and the bulk material falls from the filling hopper via the inlet opening into the downpipe.

Claims

[1] Device for filling bulk material (28), in particular powder material, with a downpipe (12) which has an inlet opening (14) at one end and an outlet opening (16) for the bulk material (28) at the other end, with a tubular film (18) lining the downpipe (12), which is fastened at its open ends to the downpipe (12) and delimits an intermediate space (22) with the downpipe (12), and with a compressed air device for introducing compressed air into the intermediate space (22) via a ventilation opening (24) in the downpipe (12) and for discharging the compressed air from the intermediate space (22) via a ventilation opening (26) in the downpipe (12). [2] Device according to claim 1, characterized by that the film (18) has a thickness between 0.08 mm and 0.15 mm. [3] Device according to claim 1 or 2, characterized bythat the film (18) is made of polyethylene (PE), in particular of pure polyethylene (LDPE or HDPE) or of a polyethylene with additives or of a material mixture whose main component is polyethylene. [4] Device according to one of the preceding claims, characterized by a control device for controlling the inlet and / or outlet of the compressed air into the intermediate space (22) and from the intermediate space (22). [5] Device according to claim 4, characterized by that the control device has at least one pressure sensor for measuring the air pressure in the intermediate space (22). [6] Device according to one of the preceding claims, characterized by that the film (18) is fastened to the downpipe (12) by means of flanges (20) placed on the downpipe (12). [7] Device according to claim 6, characterized by that the film (18) is clamped at the relevant end between the downpipe (12) and the respective flange (20). [8] Device according to claim 7, characterized by that the film (18) can be replaced without the use of tools. [9] Device according to one of the preceding claims, characterized by a filling funnel (30) connected to the downpipe (12) and opening into the inlet opening (14). [10] Device according to claim 9, characterized by that the filling funnel (30) has a shut-off valve (32). [11] Device according to one of the preceding claims, characterized by that the ventilation opening (24) and the ventilation opening (26) coincide.

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