Apparatus for dressing surface of grained material or granules

Abstract

In an apparatus below an uppermost module 7 having a centrifugal flow guide there is an axially positioned nozzle 17 supplying a dressing agent, directed onto a dispersing screen 20 which constitutes a cover of a chamber 19 arranged axially below the nozzle 17 and connected with an external blower 21, whereas above the nozzle 17 on the vertical axis of the body 1 there is positioned a shield 16, whereas below the chamber 19 there is arranged a module 10 having a centripetal flow guide, below which there is positioned another module 7 having a centrifugal flow guide, and the lower end of the body 1 is constituted by a module 10 having a centripetal flow guide.

Claims

1. An apparatus for dressing surface of a grained material or granules, having a vertical through body, provided with arranged alternately first modules having a centrifugal flow guide in a form of an axial support and a plurality of directing elements ends of which face an inner wall of the vertical through body and second modules having a centripetal flow guide in a form of plurality of directing vanes positioned on an inner wall of each one of the second modules ends of the vanes face towards the vertical axis of the vertical through body, in the vertical through body above the uppermost of one of the first modules having the centrifugal flow guide there is an axially attached hopper connected with a container of grained material, whereas the vertical through body is positioned inside a cylindrical housing, and in the upper part of the cylindrical housing, above the vertical through body, there is an axially positioned a fan driven by a motor, characterized in that below the uppermost of one of the first modules having the centrifugal flow guide there is an axially positioned nozzle supplying a dressing agent, directed onto a dispersing screen having a small openings, which constitutes a cover of a chamber arranged axially below the axially positioned nozzle and connected with an outer external blower, whereas above the axially positioned nozzle on the vertical axis of the vertical through body there is positioned a shield, whereas below the chamber there is arranged one of the second modules having the centripetal flow guide, below which there is positioned another one of the first modules having the centrifugal flow guide, and the lower end of the vertical through body is constituted by the one of the second modules having the centripetal flow guide.

2. The apparatus according to claim 1, characterized in that the upper end of the cylindrical housing is tightly closed.

3. The apparatus according to claim 2, characterized in that the lower end of the cylindrical housing is open and constitutes an outlet funnel of dressed material.

4. The apparatus according to claim 1, characterized in that the upper open end of the vertical through body is positioned below the fan.

5. The apparatus according to claim 3, characterized in that the cylindrical housing is attached to a stationary frame.

6. The apparatus according to claim 1, characterized in that a rotary air throttle 15 is mounted in the vertical through body perpendicularly to the vertical axis of the vertical through body above the hopper.

7. The apparatus according to claim 1, characterized in that a ratio of an area (F) of a cross-section of the cylindrical housing to an area (S) of a cross section of the vertical through body 1 fulfils a condition $1,3\le \frac{F}{S}\le 8.$

8. The apparatus according to claim 1, characterized in that the hopper is closed from above with a cover having a shape of a spherical cap.

9. The apparatus according to claim 1, characterized in that the shield has the shape of a spherical cap of a diameter of the base bigger than the diameter of the chamber covered with the dispersing screen having small openings.

10. The apparatus according to claim 9, characterized in that a ratio of an area (S) of a cross-section of the vertical through body to an area (G) of the dispersing screen fulfils a condition $6\le \frac{S}{G}\le 70.$

11. The apparatus according to claim 1, characterized in that the dispersing screen is shaped as a spherical cap.

12. The apparatus according to claim 11, characterized in that a ratio of an area (S) of a cross-section of the vertical through body to an area (G) of the dispersing screen fulfils a condition $6\le \frac{S}{G}\le 70.$

13. The apparatus according to claim 1, characterized in that the dispersing screen is cone-shaped.

14. The apparatus according to claim 1, characterized by having a plurality of the first modules with the centrifugal flow guide and a plurality of the second modules with the centripetal flow guide, whereas the first modules with the centrifugal flow guide and the second modules with the centripetal flow guide are positioned alternately below the chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an axial cross-section of the apparatus in a schematic view in which the three modules having centrifugal and centripetal flow guides are used.

(2) FIG. 2 shows an enlarged fragment of the apparatus showing the chamber covered with the screen shaped as the spherical cap, and

(3) FIG. 3 presents a view of a fragment of FIG. 2 seen from side of the nozzle.

DETAILED DESCRIPTION

(4) An apparatus according to the invention has a vertical cylindrical through body 1 positioned inside a cylindrical housing 2 attached to a stationary frame 3. The upper end of the housing 2 is tightly closed, while the lower end of the housing 2 is open and it constitutes an outlet funnel 4 of dressed grained material. In the upper part of the housing 2, above the open end of the body 1, there is positioned a fan 5 driven by a motor 6. The body 1 is provided with arranged alternately a modules 7, having a centrifugal flow guide in a form of an axial support 8 with a plurality of directing elements 9 of whose the ends face an inner wall of the body 1, and the modules 10 having a centripetal flow guide in a form of a plurality of directing vanes 11 arranged on an inner wall of the module 10 of whose the ends face towards the vertical axis of the body 1. Inside the body 1, above the uppermost module 7 having the centrifugal flow guide, is mounted axially a hopper 12 connected to a reservoir 13 of grained material, the hopper 12 being closed at the top by a cover 14 shaped as a spherical cap. In the body 1, above the hopper 12 a rotary air throttle 15 is fixed perpendicularly to the vertical axis of the body 1. Below the uppermost module 7 having the centrifugal flow guide, in the vertical axis of the body 1, there is situated a shield 16 shaped as a spherical cap, and on the axis of the shield 16 there is attached a nozzle 17 to feed the dressing agent supplied via a conduit 18 from a container not shown in the drawing. In the body 1 below the nozzle 17 there is situated a chamber 19, the upper cover of which is a dispersing screen 20, the chamber 19, being connected to an external blower 21 via a pipe 22. Below the chamber 19 there is the module 10 having the centripetal flow guide below which is positioned another module 7 with the centrifugal flow guides is positioned with the centrifugal flow guide. The nozzle 17 feeds the dressing agent directly onto the surface of the dispersing screen 20. The dispersing screen 20 preferably has the shape of the spherical cap, but may alternatively have a shape of a cone. The screen 20 has a plurality of evenly spaced small circular openings 23. The diameter of the base of the shield 16 is larger than the diameter of the chamber 19 covered by the dispersing screen 20, the shield 16 protects the dispersing screen 20 against agglomeration of falling grains. A ratio of an area S of a cross-section of the body 1 to an area G of the dispersing screen 20 amounts 6 to 70. The apparatus may have a plurality of the modules 7 with the centrifugal flow guide and a plurality of the modules 10 with the centripetal flow guide, said the modules 7 and 10 being arranged alternately below the chamber 19, and the module 10 with the centripetal flow guide constitutes the lower end of the body 1. The value of a ratio of a cross-section an area F of the housing 2 to the area S of a cross-section area S of the body 1 amounts 1.3 to 8. The circulation of saturated air in the body 1 is opposite to the direction of the movement of the grained material forced by the action of gravity and is marked with an arrows 24.

(5) Hereunder is described the operation of the apparatus: the grained material fed from the reservoir 13 falls out from the hopper 12 under the action of gravity and drops onto the directing elements 9 of the centrifugal flow guide in the uppermost module 7, which distribute the material uniformly in the space of the body 1. At the same time, the dressing agent fed from the container via the conduit 18 is directed by the nozzle 17 onto the dispersing screen 20, the air supplied by the tube 22 from the external blower 21 to the chamber 19 is ejected through the openings 23 in the dispersing screen 20 causing dispersing of the droplets of the dressing agent, so that very fine droplets and mist are obtained. Small droplets stick to and dress the descending grain, while the mist flowing in the opposite direction provides even grain dressing. Further, the mist is drawn by the fan 5 to the upper open end of the body 1, from which it travels to the housing 2. As a result of the operation of the fan 5 a constant induced flow is generated from the upper end of the body 1 through the space between the walls of the housing 2 and the body 1 to the lower open end of the body 1 from which the mist is sucked up. The grains falling down by the action of gravity below the chamber 19 are put into continuous oblique and swirling movement by the directing elements 9 and the directing vanes 11 of the modules 7 and 10, and while moving they are effectively dressed over their entire surface. The throttle valve 15 enables to adjust the flow rate of the dressing agent in the form of mist, depending on the type of material to be dressed.