AU628985B2 - Device for feeding out bulk material - Google Patents

Description

I II r r a L it I I r421 11~1 1 OPI DATE 08/01/91 AOJP DATE 28/02/91 APPLN. ID S'15 PCT NUMBER PCT/SE90/00217 INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 5 (11) International Publication Number: WO 90/15766 65/46 Al (43) International Publication Date: 27 December 1990 (27.12.90) (21) International Application Number: (22) International Filing Date: Priority data: 8902138-0 14 June 1 PCT/SE90/00217 3 April 1990 (03.04.90) 989 (14.06.89) (71X72) Applicant and Inventor: FORSBERG, G6ran [SE/SE]; Tuggelitevigen 3A, S-653 50 Karlstad (SE).

(74) Agent: HYNELL, Magnus; Hynell Patenttjanst AB, Box 236, S-683 02 Hagfors (SE).

(81) Designated States: AT, AT (European patent), AU, BB, BE (European patent), BF (OAPI patent), BG, BJ (OAPI patent), BR, CA, CF (OAPI patent), CG (OAPI patent), CH, CH (European patent), CM (OAPI patent), DE*, DE (Utility model)*, DE (European patent)*, DK, DK (European patent), ES, ES (European patent), FI, FR (European patent), GA (OAPI patent), GB, GB (European patent), HU, IT (European patent), JP, KP, KR, LK, LU, LU (European patent), MC, MG, ML (OAPI patent), MR (OAPI patent), MW, NL, NL (European patent), NO, RO, SD, SE, SE (European patent), SN (OA- PI patent), SU, TD (OAPI patent), TG (OAPI patent),

US.

Published With international search report.

In English translation (filed in Swedish).

628 (54) Title: DEVICE FOR FEEDING OUT BULK MATERIAL (57) Abstract The present invention relates to a device for a common feeding out of bulk materials from separate containers 2) in a desired mixing ratio, the outlets (12, 13) of the containers being placed above separate sections of an essentially horizontal conveying screw Said conveying screw is enclosed by a rotatable'drum (7,7A-7B) having inlet holes (14) for bulk materials from said containers in areas for the outlets of the containers.

I:-

See back of page i i WO 90/15766 PCT/SE90/00217 DEVICE FOR FEEDING OUT BULK MATERIAL TECHNICAL FIELD The present invention relates to a device for a common feeding out of .'.bil'ki'maiterials frrm separate containers in a desired mixing ratio, the outlets of the containers being placed above separate sections of an essentially horizontal conveying screw..

BACKGROUND ART It has already been suggested, that different bulk materials be mixed by means of a conveying screw, which rotates in a stationary drum, which encloses the conveying screw. DE-B-1 200 788 and FR-A-2 171 055 relate to examples of this technique.

The value of this technique is however limited, since it is either necessary to choose small inlet holes in order to prevent a clogging of the thread path already by the material which is fed through the inlet hole for the first bulk material, a small transport capacity in this way being obtained, or to make the inlet holes larger, said risk of clogging in this case being experienced already from the beginning, no or merely a small amount of material being fed through the next inlet hole, i.e. the desired mixing not taking place or being reduced to a great extent. In order to counteract these effects said inlet holes for the different bulk materials have been placed close to each other in the initial end of the conveyor screw, more precisely at a distance of just 1-2 thread turns. Such a construction will of course have a very minor capacity. It is true that this capacity to some extent can be increased by increasing the rotation speed of the conveying screw, but this of course is also not a satisfactory technical solution.

The above-mentioned problems can be eliminated to some extent by using a so called para screw instead of a normal conveying screw, i.e. a screw having increasingly deep thread paths in the transportation direction of the screw. NO-C-83 991 shows 1 1 1 1 *r v 1 B' 1 1 1

,^A

1 Iil l a iS^ 2 an example of this technique. However, the value of the para screw is limited, since it can not be made very long with a maintained reasonable thickness. Thus, it is useful only in smaller units, e.g. for the use described in NO-C- 83 991, namely mobile concrete mixers.

BRIEF DISCLOSURE OF THE INVENTION The present invention provides a device for common feeding out of bulk materials from separate containers in a desired mixing ratio comprising; at least two containers each container having an outlet located above separate sections of a conveying screw, characterized in that said conveying screw is enclosed by a rotatable drum having inlet holes for bulk materials from said containers in the areas of the outlets of the containers.

*BRIEF DESCRIPTION OF DRAWINGS In the following description of two preferred embodiments reference will be made to the accompanying drawings, in 20 which: Fig. 1 is a perspective view showing the basic principle of the invention; ee Fig. 2 is a sectional view of the discharge device as well as the containers according to a first embodiment; and 25 Fig. 3 shows in a side view a second embodiment of the discharge device.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring firstly to Figs. 1 and 2 a first container is designated 1 and a second container designated 2.

Containers 1 and W090/15766 PC/SE90/00217 3 2 respectively contain a first bulk material 3 and a second bulk material 4 respectively, the latter to be mixed with the first bulk material in a certain desired mixing proportion.

Between containers 1 and 2 there is a partition Along the bottom of the containers a so called feeder tube 6 extends, common to the two containers, i.e. a bulk mass transport device of the type shown in document SE-C-404 684. Feeder tube 6 comprises, according to the pricinples known through i.a. this patent specificatio, a cylindrical drum 7, designed to rotate about its axis 8, and inside drum 7 a conveying screw 9, coaxially disposed in relation to the drum and its direction of rotation being opposite to the direction of rotation of drum 7. Drum 7 is rotated by means of a motor 10 and screw 9 is rotated by means of a motor 11, Fig.

2. Feeder tube 6 is, as has been mentioned, disposed in the bottom of containers 1 and 2 and surrounded by bulk materials 3 and 4 respectively along that entire length of the feeder tube, which extends through containers 1 and 2, i.e. the drum, inside those areas where the drum is surrounded by bulk materials 1 and 2, is exposed to outlets 12 and 13 respectively for bulk materials of the containers. Within these areas, which include the main part of the total length of feeder tube 6, drum 7 is provided with a plurality of inlet openings 14 in the shape of axial slits, which according to this embodiment is evenly distributed on the surface of drum in its axial as well as in its periphery direction. In the outlet end outlet holes 15 are placed above a belt conveyor 16. Inspection holes in the bottom of containers 1,2 are designated.17.

When drum 7 and conveying screw 9 are rotated in opposite directions,bulk materials 3 and 4 fall. into drum 7 through slits 14 along the entire length L. Drum 7 and screw 9 are rotated with such a speed, that the material which is fed into drum 7 will not fill; it to a greater extent than to a certain part of its cross-section. -Consequently, the particles in bulk materials 3 and 4 are not stopped by materials, which have already been fed into drum 7, but are able to fall through Y 3 1 l v l I 1 1 1 l l l f l 1 1 1 _J i l WO 90/15766 PCT/SE90/00217 slits 14 with the same ease regardless where they are located along length L of the drum. Thus, in accordance with the known working principle of feeder tube 6, the bulk material is allowed to be fed into the drum completely uniformly at different locations along length L1 of first container 1 and along length L2 of second container 2 respectively. However, the loading speed of the two bulk materials 3 and 4 can be different, depending on the different properties and particle sizes of materials 3 and 4. Thus, in order to obtain the desired mixing ratio in material 18, which is fed onto belt conveyor 16, partition 5 preferably is disposed in such a way, that it can be located in different positions along length L, i.e. for an adjustment of the ratio L 1

/L

2 Through a variation of the ratio L 1

/L

2 the mixing ratio.in the discharged material 18 is adjusted.

Fig. 3 shows another particular embodiment of the invention.

Those parts of the construction, which are unchanged as compared to the above described embodiment, have the same reference numerals as in Figs. 1 and 2. Thus, information about these parts is found in the description supra. Thus, e.g.

partition 5 preferably can be placed in different positions, which, according to this embodiment, can be used to roughly adjust the mixing ratio in the discharged bulk material 18.

The novel feature of this embodiment is that the drum has been subdivided into two sections. 7A and 7B. The two sections 7A and 7B can be rotated independently of each other but are connected to each other through a race bearing 20. Race bearing is according to Fig. 3 .placed below partition 5 but does not have to be placed in the area of wall 5, which preferably can be placed in different locations along, the assembled drum 7A/7B. First drum section 7A is driven by means of a motor 21 and second drum section 7B by means of a motor 10. Conveying screw 9 is common to the two drum sections 7A and 7B and extends through the two sections. It is driven by motor 11.

By means of motors 21 and 10 drum sections 7A and 7B respectively can be rotated with different and varying rotation WO 90/15766 PCT/SE90/00217 speeds, and in this way the loading speed of bulk materials 3 and 4 to the assembled drum 7A/7B can be adjusted. This can be utilized to fineadjust the mixing ratio, but it can also be used as the only adjustment instrument, in case partition 5 is fixedly disposed between containers 1 and 2. The possibility of influencing the mixing ratio through a variation of the absolute and/or relative rotation speeds of drum sections 7A and 7B is of course particularly advantageous, since this adjustment can be done, when containers 1 and 2 already have been filled with bulk materials 3 and 4 respectively, whereas it is very difficult or impossible to move partition 5 in this situation.

In the described embodiment holes/slits 14 are evenly distributed on the surface of the drum. However, this does not always have to be the case. It is possible to arrange the holes non-uniformly, e.g. use more holes per surface unit in one section of the drum in order to increase the feeding into this section. The drum can also be disposed in such a way, known per se, that it is laterally movable, the drum digging its path through the bulk material. Also, it is possible to use more than two containers and below or in the bottom of these containers dispose a common feeder tube, in the way described supra. Thus, t L present invention is not limited to the described embodiments, which merely serve as two illustrated embodiments within the scope of protection of the inventive idea.

1 c 1 11 1 1 1 1 11 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 l i i

II

Claims (4)

1. A device for common feeding out of bulk materials from separate containers in a desired mixing ratio comprising; at least two containers each container having an outlet located above separate sections of a conveying screw, characterized in that said conveying screw is enclosed by a rotatable drum having inlet holes for bulk materials from said containers in the areas of the outlets of the containers.

2. A device according to claim 1, characterized in that the outlet of each container is arranged above separate sections of the rotatable drum and that the ratio between the length of the separate sections of the rotatable drum, provided with inlf't holes for the bulk materials, which the drum exposes to the respective outlets from the containers, ;can be varied in order to adjust the mixing ratio. S090

3. A device according to claim 2, characterized in that said ratio between the length of said separate sections of the rotatable drum is variable by a movable partition S• between the separate containers.

4. A device according to claim 1, characterized in that the drum along its length has at least two sections which are rotatable at different speeds, in that at least one of said sections is rotatable with a variable speed, and in that those sections of the rotatable drum, provided with inlet holes for bulk materials, which the drum exposes to the respective outlets from the containers, at least partially coincides with said sections of the drum having different rotation speeds, the mixing ratio being varied by S varying the rotation speed ratio of the sections of the S 7 drum. A device according to claims 2 and 4, characterized in that it is possible to roughly adjust the mixing ratio by using a variable ratio between the length of those sections of the rotatable drum, provided with inlet holes for bulk materials, which the drum exposes to the respective outlets of the containers, and in that the mixing ratio can be fineadjusted, since the drum along its length is provided with at least two sections, which are rotatable with different speeds, at least one of the sections being rotatable with a varying speed and those sections of the rotatable drum, provided with inlet holes for bulk materials, which the drum exposes to the respective outlets from the containers, at least partially coinciding with said sections of the drum, which can rotate with different speeds. Dated this 18th day of June 1992 Goran FORSBERG By His Patent Attorneys: GRIFFITH HACK CO Fellows Institute of Patent Attorneys of Australia. V t S D50 o* oooo 1 I 'o o o*