MIXING DEVICE, MIXING HOPPER AND DOSING CONTAINER

Abstract

Mixing device 1, dosing container and mixing hopper for mixing a synthetic starting material with an additive, in particular a granular additive or additive in powder form, comprising a mixing housing 10 with an inlet 14 for allowing the substances into a mixing chamber 12 bounded by the mixing housing and an outlet 16 for discharging the substances from the mixing chamber in mixed form, wherein a rotor body 11 is provided on a rotatable shaft 17 in the mixing chamber and comprises on a side a number of rotor arms 18 extending parallel to the shaft in the direction of an opposite wall of the mixing housing 10, and wherein the opposite wall of the mixing housing is provided with a number of stator arms 19 extending parallel to the shaft in the direction of the rotor body, and wherein a mixing hopper is provided having an infeed side for receiving a flow of the substances for mixing and an outfeed side which is in open communication with the inlet of the mixing housing 10, and wherein a dividing body is provided between the infeed side and outfeed side in order to divide the flow of the substances for mixing into a number of at least substantially equal part-flows.

Claims

1. Dosing container for application in a mixing device for mixing a synthetic starting material with an additive, in particular a granular additive or additive in powder form, comprising a space bounded by a container wall for containing a supply of a substance for mixing and carrying a dosed quantity of the substance therefrom to a mixing housing of the mixing device, which space is in air-exchanging communication with an ambient air via an air filter, and wherein the dosing container is provided with measuring means which are able and configured to measure a weight change in the container, characterized in that the dosing container comprises further aerating means which are able and configured to allow air into the dosing container.

2. Dosing container as claimed in a claim 1, characterized in that the further aerating means comprise a non-return valve in a wall of the dosing container.

3. Mixing hopper for application in a mixing device for mixing a synthetic starting material with an additive, in particular a granular additive or additive in powder form, which mixing hopper is open on an infeed side in order to receive a flow of the substances for mixing and leaves an opening on an outfeed side in order to discharge the substances to a mixing housing of the mixing device, and wherein a dividing body is provided between the infeed side and outfeed side in order to divide the flow of the substances for mixing into a number of at least substantially equal part-flows, characterized in that a rotatable stirring body is provided between the dividing body and the outfeed side which is able to rotate through the part-flows with a stirring part in a plane transversely of a flow direction of the substances for mixing.

4. Mixing hopper as claimed in a claim 3, characterized in that a further rotatable stirring body is provided between the infeed side and the dividing body which is able to rotate through the flow with a stirring part in a plane transversely of a flow direction of the substances for mixing.

5. Mixing device for mixing a synthetic starting material with an additive, in particular a granular additive or additive in powder form, comprising a mixing housing with an inlet for allowing the substances into a mixing chamber bounded by the mixing housing and an outlet for discharging the substances from the mixing chamber in mixed form, wherein a rotor body is provided on a rotatable shaft in the mixing chamber and comprises on a side a number of rotor arms extending parallel to the shaft in the direction of an opposite wall of the mixing housing, and wherein the opposite wall of the mixing housing is provided with a number of stator arms extending parallel to the shaft in the direction of the rotor body, characterized in that a mixing hopper is provided having an infeed side for receiving a flow of the substances for mixing and an outfeed side which is in open communication with the inlet of the mixing housing, and wherein a dividing body is provided between the infeed side and outfeed side in order to divide the flow of the substances for mixing into a number of at least substantially equal part-flows.

6. Mixing device as claimed in claim 5, characterized in that the mixing hopper is provided between the dividing body and the outfeed side with a rotatable stirring body which is able to rotate through the part-flows with a stirring part in a plane transversely of a flow direction of the substances for mixing.

7. Mixing device as claimed in claim 5, characterized in that the mixing device comprises a dosing container for containing a supply of a substance for mixing and for carrying a dosed quantity of the substance therefrom to the mixing housing, wherein the dosing container is provided with measuring means which are able and configured to measure a weight change in the container, wherein the dosing container comprises an air filter for aerating a content of the dosing container and wherein the dosing container comprises further pressure-sensitive aerating means which are able and configured to allow air into the dosing container.

8. Mixing device as claimed in claim 7, characterized in that the further aerating means comprise a non-return valve in a wall of the dosing container.

9. Mixing device as claimed in one or more of the foregoing claims, characterized in that the rotor arms are positioned on an imaginary circular line at a regular distance from each other and follow the imaginary circular line during rotation of the rotor body, and that the stator arms are positioned at a distance from the imaginary circular line wherein a shortest possible distance between a stator arm and a passing rotor arm amounts to a maximum of 10 mm.

10. Mixing device as claimed in claim 9, characterized in that a shortest possible distance between a rotor arm and a most closely positioned stator arm amounts to a minimum of 3 mm, and is preferably between 5 and 8 mm.

11. Mixing device as claimed in claim 9, characterized in that a first set of stator arms positioned on an imaginary circular line at a regular distance from each other and a second set of stator arms positioned on an imaginary circular line at a regular distance from each other is provided in the mixing chamber, wherein the second set of stator arms describes a larger imaginary circle than the first set of stator arms, and that a set of rotor arms positioned on an imaginary circular line at a regular distance from each other is provided at least between the first set and second set of stator arms.

12. Mixing device as claimed in claim 11, characterized in that at least one further set of rotor arms positioned on an imaginary circular line at a regular distance from each other is provided.

13. Mixing device as claimed in claim 9, characterized in that the mixing housing is cylindrical and that the mixing chamber has a circular cross-section with a diameter between 350-500 mm.

14. Mixing device as claimed in claim 9, characterized in that the shaft with the rotor body is coupled to rotation means which are able and configured to rotate the shaft with the rotor body in a first direction and in a second, opposite direction.

15. Mixing device as claimed in claim 14, characterized in that the rotation means are able and configured to change a direction of rotation of the rotor body alternately between the first direction and the second direction at a preset interval.

16. Mixing device as claimed in claim 9, characterized in that the rotor body divides the mixing chamber into a primary mixing compartment at the inlet and a secondary mixing compartment at the outlet, and comprises an opening as passage between the primary mixing compartment and the secondary mixing compartment.

17. Mixing device as claimed in claim 16, characterized in that the rotor body comprises a number of openings positioned regularly on an imaginary circular line and that sealing means are provided which are able and configured to leave clear at least one of the number of openings and to seal the remaining of the number of openings.

18. Mixing device as claimed in claim 17, characterized in that the sealing means comprise a plate-like body which is provided in the mixing chamber and is placeable in front of the remaining of the number of openings so as to seal them.

19. Mixing device as claimed in claim 9, characterized in that the rotor body comprises a circular disc, a centre of which lies out of line with a centre of a cross-section of the mixing chamber.

20. Mixing device as claimed in claim 5, characterized in that the outlet for discharging the substances from the mixing chamber in mixed form comprises a transport mechanism which determines process speed and which is configured such that the transport mechanism for transporting the substances in mixed form from the mixing chamber substantially determines the speed at which substances are supplied to the inlet of the mixing housing.

21. Mixing device as claimed in claim 20, characterized in that the transport mechanism determining the process speed comprises a dual dosing screw which is suspended such that a first dosing screw engages in a second dosing screw such that the substances are transported out of the mixing chamber in mixed form.

Description

[0032] The invention will now be further elucidated on the basis of an exemplary embodiment and an accompanying drawing. In the drawing:

[0033] FIG. 1 shows a front view of a mixing device according to the present invention with a mixing housing and a mixing hopper; and

[0034] FIG. 2 shows a side view of the mixing device according to FIG. 1.

[0035] The figures are otherwise purely schematic and not drawn to scale. Some dimensions in particular may be exaggerated to greater or lesser extent for the sake of clarity. Corresponding parts are designated as far as possible in the figures with the same reference numeral.

[0036] As shown in FIGS. 1 and 2, mixing device 1 according to the present invention comprises a cylindrical mixing housing 10 which bounds a mixing chamber in which a number of substances can be mixed to a homogeneous mixture. The mixing chamber is divided here into a primary mixing compartment 12 and a secondary mixing compartment 13 by a rotor body 11 in the form of a circular metal disc. Provided in the mixing housing is an inlet 14 along which the substances can be carried into the primary mixing compartment. Provided in rotor body 11 are a number of openings 15 which allow passage from the primary mixing compartment to the secondary mixing compartment. An outlet 16 is provided in the mixing housing in order to discharge the substances mixed to a homogeneous mixture thereto from the mixing housing. The substances to be mixed in the mixing housing thus move during a mixing process from inlet 14 through the primary mixing compartment 12 and through an opening 15 via the secondary mixing compartment 13 to the outlet.

[0037] Rotor disc 11 is coupled rotatably to a central drive shaft 17 in the mixing chamber. Via central drive shaft 17 rotor disc 11 can be driven so as to rotate in a first direction as well as in an opposite second direction. Control means which change a direction of rotation of the drive shaft at a preset interval can be coupled to the drive shaft for this purpose.

[0038] Provided on the rotor disc are rotor arms 18 which rotate through the mixing chamber during rotation of the rotor disc. On a first side of the rotor disc a number of the rotor arms extend parallel to central drive shaft 17 from the rotor disc in the primary mixing compartment in the direction of a first wall of the mixing housing. In similar manner a number of the rotor arms extend parallel to the central drive shaft 17 from the rotor disc in the secondary mixing compartment in the direction of a second, opposite wall of the mixing housing. In both mixing compartments the rotor arms are provided here as a set of rotor arms which are positioned on an imaginary circular line at a regular distance from each other and which follow the imaginary circular line during a rotation of the rotor disc.

[0039] A set of stator arms 19 is also provided on either side of the imaginary circular line in each mixing compartment. The stator arms extend parallel to the rotor arms in the primary mixing compartment from the first wall of the mixing housing, a removable cover, in the direction of the rotor disc. In similar manner stator arms extend parallel to the rotor arms in the secondary mixing compartment from the second wall of the mixing housing in the direction of the rotor disc. Because the stator arms are fixed on the mixing housing, they do not co-displace during a rotation of the rotor disc. The rotor arms thus move along the stator arms in order to realize a mixing of substances received in the mixing housing. The rotor arms and stator arms are placed in the mixing compartments such that a smallest possible distance between a stator arm and rotor arm amounts to a maximum of 10 mm. Such a relatively close distance between a stator arm and passing rotor arm of a maximum of 10 mm results in a breakdown of compact pieces in the mixture, so that the mixing device is particularly suitable for mixing substances which tend to display a relatively high degree of clotting, for instance the addition of a mineral in relatively fine powder form, such as calcium carbonate, to a synthetic starting material such as for instance polyvinyl chloride.

[0040] The mixing device further comprises a mixing hopper 20 which is provided on top of the mixing housing and is in open communication with inlet 14 on an outfeed side in order to supply substances to the mixing housing. Opposite the outfeed side the mixing hopper is open on an infeed side so as to be filled there with substances for mixing. Between the infeed side and outfeed side a dividing body is provided in the mixing hopper which divides the flow of the substances for mixing into a number of at least substantially equal part-flows. The dividing body provides for a premixing of the separate substances to a premixture which is suitable for further processing in the mixing housing to a final mixture with the desired homogeneity. Provided between the dividing body and the outfeed side for the purpose of enhancing a proper throughflow of the substances in the mixing hopper is a rotatable stirring body 21 which can rotate through the part-flows in the mixing hopper with a stirring part in a plane transversely of a flow direction of the substances for mixing.

[0041] Although the invention has been further elucidated with reference to only a few exemplary embodiments, it will be apparent that the invention is by no means limited thereto. On the contrary, many other variations and embodiments are possible within the scope of the invention for the person with ordinary skill in the art.