WO1986000829A1

WO1986000829A1 - A device for distribution of finely divided material over a surface

Info

Publication number: WO1986000829A1
Application number: PCT/SE1985/000299
Authority: WO
Inventors: Ralf Larsson
Original assignee: Ralf Larsson
Priority date: 1984-08-01
Filing date: 1985-08-01
Publication date: 1986-02-13
Also published as: SE8403935D0; SE8403935L; EP0188597A1

Abstract

Device for distribution of powder, particles of flocculated material over a surface, incorporating a housing (1) having at least one opening (10) arranged along the bottom thereof and intended for discharging distributed material and a shaft (8) rotatably supported in the longitudinal direction, said shaft being equipped with a fixed brush (9) helically arranged along the shaft, said brush being intended to brush the material to be distributed towards said openings, the housing (1) being provided with an inlet (2), for the material to be distributed, arranged at one end thereof, and with an outlet (6) for excess material provided at the opposite end of the housing after said openings (10), whereby the brush (9) is intended, during the rotation of said shaft, to convey, like a worm conveyor, material between said inlet and said outlet, and thereby in a manner known per se discharge material through said openings (10).

Description

A DEVICE FOR DISTRIBUTION OF FINELY DIVIDED MATERIAL OVER A SURFACE

Background, of the invention

The present invention refers to a device for distribution of powder, particle or flocculated material over a surface, and incorporating a housing having at least one opening arranged along the bottom thereof for discharging distributed material, and a shaft rotatably supported in the longitudinal direction of the housing, which shaft is provided with a fixed brush helically arranged along the shaft, said brush being intended to brush the material to be distributed towards said openings in the housing.

At many occasions it is desirable to be able to produce an even and uniform distribution of a finely divided material, e.g. sand, flocculated fibres or the like upon a surface. At such an application it is often possible to use electrostatic application.

At industrial application of such finely divided material upon different carrier materials it is often required that the quantity of material applied is rather accurate, and for this purpose has earlier been used rotary vane feeders, shaking tables and the like. In one embodiment has also been used a gravity shaft, which is charged by means of a rotary vane feeder, and in the bottom of which is arranged a screen. A rotatable brush is arranged above the bottom of the screen and at its rotation the material to be distributed hopefully will be evenly distributed over the entire surface of the screen, from where it is brushed down through the screen to the surface material therebelow, by means of said brush. Particles, which are bigger than the openings of the screen, however will remain and will cause a blocking of the screen after a period of time.

These industrially utilized distribution devices due to the necessity of using rotary vane feeders or other dosing apparatuses furthermore have rather a complex design and are therefore expensive, and at embodiments with electrostatic application there are also problems regarding the insulation of the components of the device which are not to be electrostatically charged.

Purpose and most essential features of invention

The purpose of the invention is now to provide a device for distribution of powder, particle or flocculated material over a surface, of the type defined in the preamble of claim 1, which device is considerably simplified as compared to earlier devices for this purpose and which is efficient and easily insulated at use of electrostatic application, and this has been achieved in that the housing is provided with an inlet for the material to be distributed, positioned at one end thereof, and an outlet for excess material provided after said openings at the opposite end of the housing, said brush being adapted at the rotation of said shaft in the manner of a worm conveyor, to transport material between the inlet and the outlet, and thereby in a manner known per se discharge material through said openings.

Description of the drawings

The invention will hereinafter be further described with reference to an embodiment shown in the accompanying drawing.

Figure 1 shows in perspective a device according to the invention with wall portions partly cut away for the sake of clearness.

Figure 2 shows diagrammatically in a side view in longitudinal cross section the device according to figure 1 adapted for electrostatic application.

Figure 3 is a cross section along line III-III in figure 2, and

Figure A shows in a planar view the underside of the discharging area of the device. Description of embodiments

In figure 1 is shown in perspective a device according to the invention, which incorporates an elongated, mainly horizontally arranged and tubular housing 1, which in the figure is shown with partly cut away wall portions in order to give the picture an increased clearness. The device however will operate as well if the housing is arranged vertically. The elongated housing 1 is provided with an inlet 2 (see fig. 2) arranged at the top thereof and to which is connected a filling conduit 3, through which material to be distributed in the device is supplied. The inlet opening 2 is provided adjacent one end of the housing and in the housing outside said inlet is arranged a wall 4 with a driving motor 5 provided outside said wall, which motor can be located at the opposite end of the housing as well. The housing is at the opposite end provided with a downward directed open outlet socket 6.

In the wall 4, which sealingly separates the space enclosing the motor 5 from the other parts of the housing, there is arranged a center bearing 7, in which is supported a shaft 8, which in cantilever-wise extends through the housing between the inlet 2 and the outlet 6, and which is rotated by the driving motor 5. The shaft 8 is equipped with a brush 9 arranged helically thereabout and being nonrotatably connected to the shaft.

In the bottom of the housing 1 along the space between said inlet 2 and outlet 6 is arranged at least one opening e.g. an elongated slot or as in the case shown, a large number of openings 10, in the embodiment shown the holes in a net 11.

In figure 2 is shown in a longitudinal section a device corresponding to that shown in figure 1, but which however is adapted for electrostatic application of the distributed material, and current supply 12. is for this purpose arranged to the wall 4, and the voltage is via sliding contacts 13 fed to the shaft 8, and preferably to a thin thread 14 wound around said shaft. The part of the shaft 8 situated on the opposite side of the wall 4 is preferably electrically insulated from current supply.

The shaft 8 may alternatively be coated with a thin electrically conductive layer, e.g. a copper layer or the like.

Below the housing 1 there is in this figure schematically shown a material surface 15, which is earthed in order to cause a potential difference between the distributing device and the distributed material on one hand and the material surface 15 on the other hand.

In figure 3 is shown in section a portion of the device according to the invention with means for electrostatic application, whereby the connection differs from that according to figure 2 in that the current supply 16 is instead arranged to the net 11 forming the openings. As can also be seen from this view the net is equipped with adjustable covering ledges 17, which can be individually displaced and locked in desired positions.

As can also be seen from this figure the bristles of the brush project through the openings whereby an automatic rinsing of the openings is also achieved.

In figure 4 is finally shown the underside of the net 11 of the outlet openings, and from this it can be seen that the covering ledges can be adjusted thus that the outlet opening has an increasing width in a direction from the inlet towards the outlet. It is also possible to use several covering ledges arranged after each other in the longitudinal direction of the housing and being individually adjustable, whereby it is possible to obtain different discharged quantities in different positions along the longitudinal direction of the housing.

The function of the device according to the invention is the following:

Material that shall be distributed, e.g. sand, flocculated fibres etcetera, is supplied via the conduit 3 through the inlet 2 to the interior of the housing. No accurate dosing of the material is thereby neccesary. The motor 5 rotates the shaft 8, whereby the helical brush 9 like a worm conveyor transports the material in a direction from the inlet towards the outlet. During this way particles of the material will fall through the openings. The quantity of material falling through is depending on the rotational speed of the shaft and of the total area of the openings 10. Excess material and bigger particles will be fed out through the outlet 6.

At electrostatic application the particles will pass through an electrostatic field generated between an electrode and an earthed surface, whereby the electrode is constituted by the shaft/the brush or the net. By giving the electrode generating the field a small mass it is achieved that it is possible to limit the condenser effect. By using a thin conductor or a conducting surface layer on the shaft it is obtained a satisfactory charging effect at a small contact member mass. It is hereby possible to get a big freedom of material choice for different parts of the device.

By choice of appropriate material in housing 1 and brush 9 it is also possible to cause the electrostatic charging of the electrostatic field required for the electrostatic application, by means of the friction when the brush rotates against the walls of the housing. Such appropriate material combinations may e.g. be NYLON/TEFLON or TEFLON/ POLYESTER .

Due to the design of the device with one brush which in the manner of a worm conveyor moves the material from the inlet to the outlet, and thereby, by adjustment of the motor speed and setting of the covering ledges, deposits adjustable quantities of material, whereas the excess is fed out at the outlet, is obtained that the requirement of accurate dosing devices is eliminated.

The invention is not limited to the embodiments shown in and described in connection to the drawings but modifications and variations are possible within the scope of attached claims.

Claims

1. A device for distribution of powder, particle or flocculated material over a surface, incorporating a housing (1) having at least one opening (10) arranged along the bottom thereof for discharging distributed material, and a shaft (8) rotatably supported in the longitudinal direction of the housing, which shaft is provided with a fixed brush (9) helically arranged along the shaft, said brush being intended to brush the material to be distributed towards said openings in the housing, c h a r a c t e r i z e d t h e r e i n, that the housing (1) is provided with an inlet (2) for the material to be distributed positioned at one end thereof, and an outlet (6) for excess material positioned after said openings (10) at the opposite end of the housing, said brush (9) being adapted at rotation of the shaft, in the manner of a worm conveyor to transport material between the inlet and the outlet, and thereby in a manner known per se discharge material through said openings (10).

2. A device according to claim 1 , c h a r a c t e r i z e d t h e r e i n, that the brush (9) is arranged to project with its bristles through said openings (10).

3. A device according to claim 1 or 2, c h a r a c t e r i z e d t h e r e i n, that said openings (10) in the bottom of the housing are holes in a net (11).

4. A device according to anyone of the preceding claims, c h a r a c t e r i z e d t h e r e i n, that the total discharge area of said openings (10) in the transverse direction of the housing is variable.

5. A device according to claim 4, c h a r a c t e r i z e d t h e r e i n, that the total discharge area of said openings (10) in the transverse direction of the housing is variable by means of at least one movable covering ledge (17).

6. A device according to claim 5, c h a r a c t e r i z e d t h e r e i n, that the housing is equipped with several individually adjustable covering ledges (17) provided after each other in the longitudinal direction of the housing for setting of different discharge areas in different sections of the housing.

7. A device according to anyone of the preceding claims, c h a r a c t e r i z e d t h e r e i n, that the discharge openings of the housing have a continuously increasing area in a direction from the inlet (2) towards the outlet (6).

8. A device for distribution of powder, particle or flocculated material over a surface, according to anyone of the preceding claims, whereby the application upon the surface is effected in electrostatic manner, c h a r a c t e r i z e d t h e r e i n, that members (14,11) are provided for charging a component in the housing (1) acting as electrode.

9. A device according to claim 8, c h a r a c t e r i z e d t h e r e i n, that the shaft (8) carrying the brush (9) is supported in a bearing (7) provided in a wall (4) in the housing and from there is arranged in cantilever-wise over the portion of the housing (1) provided with said openings (10), whereby the members (14) for charging the electrode are arranged on the ca ntilevering side of said wall (4), whereas the driving means (5) for the shaft is provided on the other side thereof, and the space on said other side of the wall (4) being electrically insulated from the portion of the housing provided with said openings (10).

10. A device according to claim 9, c h a r a c t e r i z e d t h e r e i n, that adjacent the bearing (7) there are arranged supply means e.g. sliding contacts (13) for supply of charging current to the shaft (8), which is provided with contact means (14) having a small mass and being adapted to constitute said electrode.

11. A device according to claim 10, c h a r a c t e r i z e d t h e r e i n, that the electrode is constituted by a fine charging thread (14) arranged along the shaft (8) and preferably helically wound about it.

12. A device according to claim 10, c h a r a c t e r i z e d t h e r e i n, that the electrode is constituted by a thin-walled metal coating of the shaft (8), e.g. a cqpper-plating.

13. A device according to claims 3 and 9, c h a r a c t e r i z e d t h e r e i n, that means (16) are provided for supply of a charging current to the net (11) provided with said openings.

14. A device according to claim 8 or 9, c h a r a c t e r i z e d t h e r e i n, that brush (8) and housing (1) are of such a material combination as to give an electrostatic friction charging.