DE9319542U1 - Device for dosing absorbent substances - Google Patents

Description

GAB Company for Plant Engineering and Operational Rationalization mbH, Walter-Geerdes Straße 5, 28307 Bremen

"Device for dosing absorbent materials"

The invention relates to a device for dosing absorbent substances.

The invention is particularly applicable to the dosing of absorbent solid materials, e.g. fiber materials that are added to plaster, screed and the like in order to improve the strength of these materials. According to the prior art, these fibers were weighed by hand and manually added to a mixer. Furthermore, the use of so-called fiber discharge floors was known, in which fiber material was fed through a filling nozzle of a conveyor screw and was conveyed directly to the mixer. These fiber discharge floors had the disadvantage that with a continuous material feed, the amount of the actually dispensed metered material was difficult to estimate due to the conveying time of the screw and fiber material sometimes got stuck in the area of the conveyor screw.

2427 Bremen:

Hollerallee 32, D-28209 Bremen Postf. 10 71 27, D-28071 Bremen Telephone (04 21)3 40 Fax (04 21) 3 49 17 Telex 244 958bopatd

Berlin:

Uhlandstrasse 173/174 D-10719 Berlin

Munich:

Franz-Joseph-Strasse 38
D-80801 Munich

Leipzig:

Phillip-Rosenthal-Strasse D-04103 Leipzig

Dusseldorf:

Neßlerstrasse D-40593 Düsseldorf

Telephone (0 89) 34 70 80 Telephone (03 41) 29 4428 Telephone (02 11) 71 89 83

Fax· (»30)8 8139.27· «Fax^ &iacgr;089)3·&Idigr;7010 Fax (0341)310325 Fax (0211)7182750

Telex "83.661IfTOnJd "iTelexfcäfJfe farto d

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was retained. Therefore, the dosing accuracy of these fiber discharge floors was low. Due to the poor cleaning options, the fiber discharge floors mentioned were only suitable for one type of fiber and their maintenance was time-consuming and labor-intensive.

It is the object of the present invention to provide a device for dosing absorbent materials, which enables a higher dosing accuracy and can be largely automated.

The object is achieved by a device for dosing absorbable substances, which comprises: a storage container containing the dosing material, a quantity measuring device for measuring the quantity of dosing material in the storage container and a suction device for sucking dosing material out of the storage container in a gas stream, which is followed by a separating device separate from the storage container for retaining sucked-out dosing material.

In an advantageous embodiment, the device according to the invention can comprise a dispensing device for dispensing the dosing material retained in the separating device.

The invention can further provide a control device which receives a measurement signal from the quantity measuring device and controls the suction device and, if applicable, the dispensing device.

Advantageously, it can be provided that the quantity measuring device measures the quantity of the dosing material in the storage container during suction

BOEHMERT & BOEHMERT, NQRßEMANN and PARTNER

permitted by the suction device.

The invention proposes that the quantity measuring device comprises a scale.

In one embodiment of the invention, it can be provided that the control device determines the amount of dosing material contained in the storage container before suctioning the dosing material out of the storage container, monitors the amount of dosing material contained in the storage container during suctioning and stops suctioning when a predetermined amount of dosing material has been suctioned out of the storage container.

The invention may further provide that the suction device comprises a liftable suction head.

It can be provided that the suction head is pivotably connected to a suction pipe.

Furthermore, the invention proposes that the suction device comprises a milling device for crushing the dosing material in the storage container.

The invention can provide that the control device ignores the signal from the scale while the milling head is active.

The invention can further provide that the control device raises the suction head after suctioning the dosing material out of the storage container into a position in which the suction generated by the suction device is not sufficient to suction the dosing material out of the storage container.

BOEHMERT & BOEHMERT, N0RP.EMANN and PARTNER

The invention can also provide that the control device maintains the gas delivery through the suction head after lifting for a period of time that is longer than the delivery time of the dosing material from the suction head to the separating device .

The invention also proposes that the separating device comprises a container which is divided into two separate spatial areas by a filter device for the dosing material, wherein a gas inlet opening and a gas-tight sealable discharge opening are provided in one of these two areas and a gas outlet opening is provided in the other of these two areas and the gas outlet opening is connected to a vacuum generator.

It is further proposed that the suction device comprises a flexible gas conveying line which is connected to the gas inlet opening.

It can be provided that the container is divided into two spatial areas by the casing of an elongated hollow body which passes through the container and is provided with the gas inlet opening on its upper side and the closable discharge opening on its lower side, the interface between these two spatial areas consisting at least partially of a gas-permeable material which retains the metered material, and in the one of these two areas which lies outside the elongated hollow body, an air outlet opening is provided which is connected to a vacuum pump.

It can be provided that the gas-permeable part

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the interface consists of a perforated sheet, which is provided with a filter fabric on the inside of the elongated hollow body, which retains the dosing material.

Advantageously, the filter fabric can be provided with a PTFE coating.

According to the invention, a collecting section can be provided in the lower region of the elongated hollow body, in which the casing of the hollow body is gas-impermeable.

Furthermore, the invention proposes that an axially movable piston is provided in the elongated hollow body for stripping the metered material from the gas-permeable wall.

Furthermore, it can be provided that the control device opens the closable discharge opening of the separating device after a certain period of time has elapsed after the suction has ended in order to discharge the separated dosing material.

It can be provided that the control device actuates the piston before opening the dispensing opening in order to strip retained dosing material from the gas-permeable wall of the hollow body.

It can also be provided that the control device actuates the piston after the dispensing opening has been opened in order to strip retained dosing material from the gas-permeable wall of the hollow body.

According to the invention, the amount of the dosing material in the storage container can be continuously monitored during suction.

BOEHMERT & BOEHMERT, NPRP.EMANN and PARTNERS

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be monitored. In this way, the suction can be precisely controlled according to the dosing specification. In an advantageous control, the gas conveyance through the suction device is continued after the suction process has ended; this ensures that the amount of dosing material retained in the separating device is equal to the amount of dosing material that has been sucked out. In an advantageous embodiment of the device, dosing material adhering to the separating device can be removed and added to the dosing quantity. This can ensure that the amount of material separated in the separating device is essentially equal to the amount of material delivered. With these measures, a significantly higher dosing accuracy can be achieved than before, whereby according to the invention a significantly faster conveying is possible than with the previously known screw conveyor. In an advantageous embodiment, the quantity measuring device is an electronic scale which is coupled to an electronic control device. Using the weight of the dosing material in the storage container as a parameter, the device according to the invention can be easily automated.

The new dosing device makes it possible to create a packaging system with reusable containers for transport between the manufacturer of the dosing material and the end user, which replaces the currently common disposable packaging (sacks, boxes, etc.). The transport containers also serve as storage containers, which means that the previous transfer into customer-side storage silos and packaging in specific dosing quantities is no longer necessary. The vacuum conveying of the dosing material makes it possible to arrange the storage container and separator at a greater distance than before and to maintain this distance - when using a flexible air conveying line -

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to adapt to changing operating conditions.

Further features and advantages of the invention emerge from the following description, in which an embodiment is explained in detail using the schematic drawings.

In the drawing figures show

Fig. 1 is a schematic representation of the inventive

dosing device in accordance with the invention;

Fig. 2 a cross section of the separator cylinder

the dosing device in Fig. 1;

Fig. 3 shows the section marked A of the

Fig. 2 in an enlarged view; and

Fig. 4 a view of the underside of the separator

decylinder of Fig. 2, with the lower end nozzle and the output nozzle removed.

The embodiment shown in the figures is a dosing device for fiber material that is to be added to plaster, mortar or the like. The dosing material is provided in a storage container 1 on an electronic scale 3. The scale 3 continuously measures the weight of the container 1 and sends a corresponding signal to a control unit (not shown). A suction head 10 can be inserted into the container 1, which is connected to a suction pipe 12 via a swivel connection 11 and can be raised together with it.

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can be raised or lowered. For this purpose, the suction pipe 12 is connected to a crossbar 14, which is guided on a vertical guide rod 16. A motor (not shown) acts on the crossbar 14 in order to move the crossbar 14 and thus the suction pipe 12 and the suction head 10 parallel to the guide rod 16. In Fig. 1, the crossbar 14 and the suction head 10 are shown in two different vertical positions.

The suction head 10 is also provided with a swivel drive 18 for swiveling against the suction pipe 12. Fig. 1 shows the suction head 10 in the lowered and raised position in various swiveled positions. Finally, a drive (not shown) is provided to swivel the suction pipe about its own axis. The stroke of the suction pipe 12 on the guide rod 16, the length of the suction head 10 and the maximum swivel angle of the suction head 10 relative to the suction pipe 12 are specified in such a way that the end of the suction head 10 can reach every point on the container 1 through a combined lifting, swiveling and rotational movement.

The suction pipe 12 is connected to the separating cylinder 20 via an air conveying line 19. The air conveying line 19 is flexible, so that the storage container 1 and the separating cylinder 20 can be moved against each other. The separating cylinder 20 is a double-walled cylinder with an outer, air-impermeable wall 22 and an air-permeable inner wall 24. The inner wall 24 consists essentially of a perforated plate 24a, which is lined on the inward-facing side with a filter fabric 24b with a PTFE coating. The perforated plate 24a and the filter fabric 24b are attached to the top and bottom of the inner wall 24 by means of an explosive device, as shown in Fig. 3.

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ring 25. This enables the filter fabric 24b to be replaced quickly and easily. The inner wall 24 divides the cylinder 20 into an annular outer space 26, which is hermetically sealed at the top and bottom, and a cylindrical inner space 28. The cylindrical inner space 28 continues at the top of the cylinder 20 in a cylinder attachment 30, which is coaxial with the cylinder 20 and has the same radius as the cylindrical inner space 28. The walls of the cylinder attachment 30 are impermeable to air. On its underside, the cylinder attachment 30 passes directly into the cylindrical inner space 28 of the separating cylinder 20 via a circular opening 32 in the cover 29 of the cylinder 20. The cylinder attachment 30 and the cover 29 are preferably manufactured in one piece.

An air inlet opening 34 is provided in the cylinder attachment 30, to which the air conveying line 19 is connected via an electric/pneumatic ball valve 35, which in turn is connected to the suction pipe 12. At the lower end of the separating cylinder 20, an air outlet opening 36 is provided in the outer wall 22, which is connected to a vacuum pump 42 via an electric/pneumatic ball valve 37, an air line 38 and a blower protection filter 40. In the cylinder attachment 30 and in the cylindrical interior 28 of the separating cylinder 20, a piston 44 is mounted so as to be movable in the axial direction along a guide rod 46 and can be moved from a position above the air inlet opening 34 to a position below the air outlet opening 36. The diameter of the piston corresponds essentially to the diameter of the cylindrical interior 28, so that when the piston 44 is moved downwards, fiber material adhering to the inner wall 24 is stripped off and in the lower area

BOEHMERT & BOEHMERT, NQRTAEMANN and PARTNERS

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of the separating cylinder 20. The separating cylinder 20 has a discharge opening 50 at its lower end in the area of the cylindrical interior 28, which is closed by a slide plate 52. The slide plate 52 is arranged between an upper end connection 54a and a lower end connection 54b and can be retracted along guide rods 56 via a pneumatic cylinder 55 so that the opening 50 is released. Above and below the slide plate, pneumatic seals 58 are provided in the end connections 54a, 54b, which are inflated when the slide plate 52 is closed so that the slide plate 52 is completely clamped and the opening 50 is hermetically sealed. Below the opening 50, a discharge connection 60 is provided which opens into a mixer 70.

The dosing device described above is controlled by the control device according to the following procedure. At the start of the dosing process, the storage container 1 with the fiber material is weighed on the scale 3 and the determined weight is stored in the control device. Furthermore, the weight of the amount of fiber material to be dispensed is entered into the control device. The control device then activates the vacuum pump 42 so that air is sucked through the air-permeable inner wall 24 of the separating cylinder and a corresponding negative pressure is generated in the air conveying line 19, the suction tube 12 and the suction head 10. The suction head 10 is now lowered via the height adjustment device 14, 16 until it is just above the surface of the fiber material in the storage container 1. Fibre material is now sucked in by the suction head 10 and fed via the air conveying line 19 and the air inlet opening 34 into the cylindrical interior 28 of the

BOEHMERT & BOEHMERT, NORftEMANN and PARTNER

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Separation cylinder 20. In the cylindrical interior 28, the air flow has a radial component towards the air-permeable partition wall 24, on which the fiber material is retained. Due to the suction effect of the air flow, the fiber material essentially remains attached to the inner wall 24, which is gradually covered with fiber material. Part of the fiber material also falls directly downwards in the cylinder and collects in the lower area of the cylindrical interior 28.

During the suction of fiber material, the weight of the storage container 1 is continuously monitored by the scale 3. Furthermore, during suction, the suction head 10 is pivoted against the suction pipe 12 and the suction pipe 12 is rotated, so that the fiber material in the storage container 1 is removed essentially evenly. This can be done by manually controlling the suction head or by automatically controlling it according to a predetermined algorithm stored in the control device. If the control device determines that the difference between the stored initial weight and the current weight of the storage container 1 is equal to the desired dosing weight, the suction head is raised so far that no more fiber material can be suctioned.

The vacuum pump 42 then remains in operation so that the dosing material, which is still in the air conveying line 19, reaches the separating cylinder 20. After a predetermined period of time, which essentially corresponds to the conveying time of the fiber material from the suction head 10 to the separating cylinder 20, the vacuum pump 42 is switched off or separated from the air outlet opening 36.

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and then the piston 44 is lowered in the cylinder to below the air outlet opening 36, whereby the fiber material adhering to the inner wall 24 is stripped off and collected in the lower area of the cylindrical interior 28. The amount of fiber material that has accumulated on the slide plate 52 after the piston 44 has been lowered is therefore essentially equal to the amount of fiber material sucked out. The air in the seals 58 is now released and the slide plate 52 is retracted so that the opening 50 is released and the fiber material falls through the opening 50 and the discharge nozzle 60 into the mixer 70. The slide plate is then returned to the closed position, the seals 58 are inflated and the piston 44 is returned to its rest position above the air inlet opening 44, after which the system is ready for another dosing process.

In a modification of the method described above, the piston can also be lowered during suction of the dosing material in order to clean the separating wall 24. In order to avoid a deposit of fiber material above the piston, the two ball valves 35, 37 are closed and/or the vacuum pump 42 is switched off during this process. This process can be repeated if necessary.

Furthermore, in particular in the case of larger dosing quantities, the slide plate 52 can be retracted before the piston 44 is lowered in order to deliver the dosing material to the mixer, so that the fiber material falls directly through the opening 50 and the discharge nozzle 60 into the mixer 70 when it is stripped off the wall 24.

BOEHMERT & BOEHMERT, NORDEMANN and PARTNERS

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According to the invention, dosing errors can be minimized. Because the suction head 10 does not rest on the dosing material in the storage container 1, the weight of the suction head 10 does not distort the weighing. The slight distortion of the weighing caused by the negative pressure generated by the suction head can, if necessary, be compensated for by a correction factor for the signal from the scale in the control device. In any case, however, the exact weight of the storage container 1 can be determined after the suction head 10 has been lifted out of the storage container 1.

Retention of fiber material in the air conveying line 19 can be avoided by suitable dimensioning, so that all of the fiber material extracted reaches the separating cylinder 20. With the help of the piston, it is possible to release all of the fiber material retained in the separating cylinder 20 via the opening 50. In this case, coating the separating wall 24 and the inner wall of the air conveying line 19 with a material that exerts a low adhesive effect on the fiber material is advantageous.

In a further embodiment of the embodiment shown of the dosing device according to the invention, a milling head (not shown) in the form of two spike rollers rotating in opposite directions can be attached to the end of the suction head. This milling head is used to loosen up clumped dosing material, which can then be more easily sucked out, or to produce suckable particles. Advantageously, the weighing of the storage container is suspended during the operation of the milling head, or the corresponding output signal of the electronic scale 3 is not used by the control device. In this way, falsification

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weighing during loosening can be avoided.

The features of the invention disclosed in the above description, in the drawings and in the claims can be essential both individually and in any combination for the realization of the invention in its various embodiments.

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S3632

List of reference symbols

I Storage container 3 Scale

10 Suction head

II Swivel connection 12 Suction pipe

14 Crossbar

16 Guide rod

18 Swivel drive

19 Air conveying line

20 separator cylinders

22 Outer wall of the separator cylinder

24 Air-permeable inner wall 24a Perforated sheet

24b Filter fabric

25 Snap ring

26 Annular area of the separating cylinder

28 Cylindrical interior of the separating cylinder

29 Cover of the separator cylinder 3 0 Cylinder attachment

32 Lid opening

34 Air inlet opening

35 Ball valve

3 6 Air outlet opening

3 7 Ball valve 38 Air line

40 Fan protection filters

4 2 Vacuum pump 44 Piston

4 6 Guide rod

50 Discharge opening

52 Slide plate

54a upper end fitting

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54b lower end fitting

55 pneumatic piston

56 Guide rod

58 pneumatic seal

60 discharge nozzles

70 mixers

Claims (22)

GAB Gesellschaft für Anlagenbau und Betriebsrationalisierung mbH, Walter-Geerdes Straße 5, 28307 Bremen "Device for dosing of absorbable solid substances" Claims 1. Device for dosing absorbent solid substances, characterized by a storage container (1) containing the dosing material, a quantity measuring device (3) for measuring the quantity of dosing material in the storage container (1) and a suction device (10, 12, 19) for sucking dosing material out of the storage container (1) in a gas stream, which is followed by a separating device (20) separate from the storage container (1) for retaining sucked dosing material. 2. Device according to claim 1, characterized by a dispensing device (44, 52) for dispensing the metered material retained in the separating device (20). 3. Device according to claim 1 or 2, characterized Bremen: Hollerallee 32, D-28209 Bremen Postf. 10 71 27, D-28071 Bremen Telephone (04 21)3 40 90 Fax (04 21) 3 49 17 68 Telex 244 958 bopat d Berlin: Uhlandstrasse 173/174 D-10719 Berlin Munich: Franz-Joseph-Strasse D-80801 Munich Telephone· (0.3&bgr;)·8 fl 1.CJ36 ·· Telephoi (0 89>34 70 Telefax '.(0"3O) 881 39·27· »Tttlefax &iacgr; ^O 83) 3^70 Telex 183*61«-on»d **«TelexSA*^2 forßo d Leipzig: Phillip-Rosenthal-Strasse 21 D-04103 Leipzig Telephone (03 41)29 44 28 Fax (03 41) 31 03 25 Dusseldorf: Neßlerstrasse D-40593 Düsseldorf Telephone (02 11) 71 89 Fax (02 11)7 18 27 BOEHMERT & BOEHMERT, NORDEMANN.and PARTNER by a control device which receives a measuring signal from the quantity measuring device (3) and controls the suction device (42) and optionally the dispensing device (44, 52). 4. Device according to one of claims 1 to 3, characterized in that the quantity measuring device (3) allows the measurement of the quantity of the dosing material in the storage container (1) during suction by the suction device (10, 12, 19). 5. Device according to one of claims 1 to 4, characterized in that the quantity measuring device comprises a scale (3). 6. Device according to claim 4 or 5, characterized in that the control device determines the amount of the dosing material contained in the storage container (1) before the suction of the dosing material from the storage container (1), during the suction the amount of the dosing material in the storage container (1) and the suction is stopped when a predetermined amount of dosing material has been sucked out of the storage container (1). 7. Device according to one of claims 1 to 6, characterized in that the suction device comprises a liftable suction head (10). 8. Device according to claim 7, characterized in that the suction head (10) is pivotally connected to a suction pipe (12). 9. Device according to one of claims 1 to 8, characterized in that the suction device (10) has a milling unit BOEHMERT & BOEHMERT, NORDEMANN.and PARTNER device for crushing the dosing material in the storage container. 10. Device according to claim 9, characterized in that the control device ignores the signal from the scale (3) while the milling head is active. 11. Device according to one of claims 3 to 10, characterized in that the control device controls the suction head (10) after suctioning the dosing material out of the storage container (1) into a position in which the suction generated by the suction device (42) is not sufficient to suction the dosing material out of the storage container (1). 12. Device according to claim 11, characterized in that the control device maintains the gas conveyance through the suction head (10) after lifting for a period of time which is longer than the conveyance time of the metered material from the suction head (10) to the separating device (20). 13. Device according to one of claims 1 to 12, characterized in that the separating device comprises a container (20) which is divided into two separate spatial areas (26, 28) by a filter device (24) for the metered material, wherein a gas inlet opening (34) and a gas-tight sealable discharge opening (50) are provided in one of these two areas and a gas outlet opening (36) in the other of these two areas and the gas outlet opening (34) is connected to a vacuum generator (42). 14. Device according to claim 13, characterized in that the suction device comprises a flexible gas conveying line (19) connected to the gas inlet opening (34) BOEHMERT & BOEHMERT, NORDEMANN.and PARTNER that is. 15. Device according to claim 13 or 14, characterized in that the container (20) is divided into two spatial areas by the casing (24) of an elongated hollow body which passes through the container (20) and is provided with the gas inlet opening (34) on its upper side and with the closable discharge opening (50) on its lower side, the interface (24) between these two spatial areas consisting at least partially of a gas-permeable material which retains the metered material, and in the one of these two areas (20) which lies outside the elongated hollow body, a gas outlet opening (6) is provided which is connected to a vacuum pump (42). 16. Device according to claim 15, characterized in that the gas-permeable part of the interface (24) consists of a perforated plate (24a) which is provided on the inside of the elongated hollow body with a filter fabric (24b) which retains the metered material. 17. Device according to claim 16, characterized in that the filter fabric (24b) is provided with a PTFE coating. 18. Device according to one of claims 15 to 17, characterized in that a collecting section is provided in the lower region of the elongated hollow body, in which the casing of the hollow body is gas-impermeable. 19. Device according to one of claims 15 to 18, characterized in that in the elongated hollow body an axially movable piston (44) for stripping off metered material BOEHMERT & BOEHMERT, NORDEMANN.and PARTNER from the gas-permeable wall (24). 20. Device according to one of claims 13 to 19, characterized in that the control device opens the closable discharge opening (50) of the separation device (20) after the elapse of a certain period of time after the termination of the suction in order to discharge the separated dosing material. 21. Device according to claim 20, characterized in that the control device before opening the discharge opening (50) actuates the piston (44) to strip retained dosing material from the gas-permeable wall (24) of the hollow body. 22. Device according to claim 20 or 21, characterized in that the control device actuates the piston (44) after opening the discharge opening (50) in order to strip retained dosing material from the gas-permeable wall (24) of the hollow body.