Device for producing expanded mineral granulated material

Abstract

An apparatus for producing a bloated mineral granulate with a heated processing channel (1) for the mineral granulate fed to a conveying flow (13), wherein an inflow opening (4) is provided in the processing channel (1) for forming a granulate-free laminar flow (5) running along the inner wall of the processing channel, is described. In order to design a device of the type described above in such a way that a continuous, qualitatively controllable production process is achieved, it is proposed in that the processing channel (1) comprises two channel sections (16), (17) with differing cross-sections, wherein the channel section (16) with a smaller cross-section projects into the channel section (17) with a larger cross-section, forming the inflow opening (4), and wherein the channel section (16) with a smaller cross-section is enclosed by the channel section (17) with a larger cross-section in such a way that an inflow opening (4) is formed completely around the projecting region of the channel section (16) with a smaller cross-section.

Claims

1. An apparatus for producing a mineral granulate, said apparatus comprising: a heated processing channel for mineral granulate fed to a conveying flow; said processing channel having an inflow opening therein forming a granulate-free laminar flow running along an inner wall of the processing channel; wherein the processing channel comprises two channel sections with cross-sections, one of said cross-sections being larger than the other of said cross-sections; wherein the channel section with the smaller cross-section projects into the channel section with the larger cross-section so as to form the inflow opening between an inside wall of the channel section with the larger cross-section and a portion of the channel section with the smaller cross-section that is located inside said inside wall; and wherein the channel section with the smaller cross-section is enclosed by the channel section with the larger cross-section so that the inflow opening extends completely around the portion of the channel section with the smaller cross-section that is inside said inside wall of the channel section with the larger cross-section and provides the granulate-free laminar flow along the inner wall of the processing channel.

2. An apparatus according to claim 1, wherein the processing channel has a cross-section that widens in a region of the inflow opening in an inflow direction of the laminar flow.

3. An apparatus according to claim 2, wherein the processing channel is replaceably arranged in a furnace shaft.

4. An apparatus according to claim 3, wherein the laminar flow has a process medium with a viscosity that differs from viscosity of a process medium of the conveying flow.

5. An apparatus according to claim 4, wherein heating elements operatively associated with the processing channel are arranged in a supply area of the laminar flow surrounding the processing channel.

6. An apparatus according to claim 3, wherein heating elements operatively associated with the processing channel are arranged in a supply area of the laminar flow surrounding the processing channel.

7. An apparatus according to claim 2, wherein the laminar flow has a process medium with a viscosity that differs from viscosity of a process medium of the conveying flow.

8. An apparatus according to claim 7, wherein heating elements operatively associated with the processing channel are arranged in a supply area of the laminar flow surrounding the processing channel.

9. An apparatus according to claim 2, wherein heating elements operatively associated with the processing channel are arranged in a supply area of the laminar flow surrounding the processing channel.

10. An apparatus according to claim 1, wherein the processing channel is replaceably arranged in a furnace shaft.

11. An apparatus according to claim 10, wherein the laminar flow has a process medium with a viscosity that differs from viscosity of a process medium of the conveying flow.

12. An apparatus according to claim 11, wherein heating elements operatively associated with the processing channel are arranged in a supply area of the laminar flow surrounding the processing channel.

13. An apparatus according to claim 10, wherein heating elements operatively associated with the processing channel are arranged in a supply area of the laminar flow surrounding the processing channel.

14. An apparatus according to claim 1, wherein the laminar flow has a process medium with a viscosity that differs from viscosity of a process medium of the conveying flow.

15. An apparatus according to claim 14, wherein heating elements operatively associated with the processing channel are arranged in a supply area of the laminar flow surrounding the processing channel.

16. An apparatus according to claim 1, wherein heating elements operatively associated with the processing channel are arranged in a supply area of the laminar flow surrounding the processing channel.

Description

BRIEF DESCRIPTION OF THE INVENTION

(1) In the drawing, for example, the object of the invention is shown, in which

(2) FIG. 1 is a schematic section of a device according to the invention with material feed from the head side and material discharge from the foot side in co-current operation,

(3) FIG. 2 a representation corresponding to FIG. 1 of a device according to the invention with material feed from the foot side and material discharge from the head side in counterflow operation.

WAYS TO EXECUTE THE INVENTION

(4) A device according to the invention has a processing channel 1. The processing channel 1 is arranged in a furnace shaft 3, which is surrounded by a heat insulation jacket 2. In the processing channel, an inflow opening 4 according to the invention is provided for the formation of a granule-free laminar flow 5 running along the inner wall of the processing channel.

(5) The mineral granulate, which may be based on bloatable volcanic glass, for example, is fed in via a feeding device 6, which in the design shown in FIG. 1 is assigned to a head section 7 connected to the processing channel 1. In contrast, the mineral granulate is discharged via a discharge section 9 assigned to a foot section 8, whereby the discharge can be supported by the supply of additional cooling air 10.

(6) The laminar flow 5 is fed to the processing channel 1 via feed openings 11 provided in the furnace shaft 3, whereby the head section 7 also has a discharge area 12 for the laminar flow 5 running upwards along the inner wall of the processing channel. The laminar flow 5 forms a kind of air curtain which does not mix with the granule conveying flow 13 and thus prevents the softened granules from adhering to the inner wall of the processing channel. In addition, the laminar flow 5 can be preheated so that an additional chimney effect is created which further promotes the rising and application of the laminar flow 5 to the inner wall of the processing channel.

(7) The design of a device according to the invention shown in FIG. 1 is particularly suitable for particle sizes above 100 ?m, especially since in this case the granulate particles are conveyed through the processing channel 1 by gravity. The laminar flow 5 and the granule conveying flow 13 run in opposite flow directions in processing channel 1. The residence time of the particles in processing channel 1 can be adjusted, for example, by the inflow velocity of the laminar flow 5 or an additionally provided suction in the discharge area 12.

(8) The design shown in FIG. 2 is particularly suitable for particle sizes below 100 ?m. The laminar flow 5 and the granule conveying flow 13 have the same flow direction in processing channel 1. In this design, the granulate particles are fed into the processing channel 1 as a process medium via a feed device 6 assigned to the foot section 8 by means of injected process air 14. The dwell time of the particles in processing channel 1 can again be adjusted via the inflow velocity of the laminar flow 5, the inflow velocity of the process air 14 or via a discharge unit provided in a discharge area 12 assigned to the head section 7. In addition, additional cooling air 15 can be introduced into the head section 7.

(9) Particularly favorable design conditions arise if the cross-section of the processing channel 1 widens in the area of the inflow opening 2 in the direction of inflow of the laminar flow 5, especially if the processing channel 1 comprises two channel sections 16 and 17 with different cross-sections, whereby the channel section 16 with a smaller cross-section protrudes into the channel section 17 with a larger cross-section, forming the inflow opening 4. In this case, the channel sections 16 and 17 may each have a circular cross-section and be aligned coaxially with respect to their longitudinal axis, the channel section 16 being partially pushed into the channel section 17. The cross-sectional geometry of the processing channel 1 or the channel sections 16 and 17 can be freely selected, whereby particularly favorable process conditions are achieved with a circular cross-section. According to a design, it can also be provided that processing channel 1 or channel sections 16 and 17 are formed by a suitable, heat-resistant foil.

(10) It can also be provided that the laminar flow 5 discharged via the discharge area 12 is fed to a heat exchanger, for example for heat recovery, so that the process heat can in turn be transferred to a newly supplied process air 18 forming the laminar flow 5.

(11) The processing channel 1 can be arranged replaceably in the furnace shaft 3, so that, for example, the channel sections 16 and 17 can be removed individually or together from the furnace shaft 3 in order to be able to carry out any necessary maintenance work more easily or to replace the processing channel 1 or the channel sections 16 and 17. Likewise, the head section 7 and the foot section 8 can each be attached interchangeably to the processing channel 1 and/or the furnace shaft 3, thus enabling a modular design of the device that can be adapted to the intended application. Thus, it is possible to change, for example, between a countercurrent process according to FIG. 1 and a co-current process according to FIG. 2 or between a process with particle sizes above 100 ?m and below 100 ?m by only minor modifications or by simply exchanging the head section 7 with the foot section 8.

(12) The device may have a supply area 19 for the laminar flow 5 surrounding the processing channel 1. In the supply area 19, heating elements 20 for the processing channel 1 can be arranged, which then simultaneously serve to heat the laminar flow 5. The heat input into the laminar flow can, for example, be adjusted via the inflow velocity of the process air 18 forming the laminar flow 5 into the supply area 19.