GB2089754A

GB2089754A - Device at suction conveyors for continuous transport of debris

Info

Publication number: GB2089754A
Application number: GB8134573A
Authority: GB
Original assignee: CARLSEN H W AB
Current assignee: CARLSEN H W AB
Priority date: 1980-11-17
Filing date: 1981-11-17
Publication date: 1982-06-30
Also published as: HK43288A; ES8300296A1; ES507219A0; FR2516489A3; DE3145600A1; JPS57112227A; GB2089754B; FR2516489B3; SG13988G; SE8008048L

Abstract

A conveyor arrangement for the continuous transport of debris comprises a container 1 housing a filter 2, and a suction pump 4 arranged to create an air current into the container through a conveyor tube 5 and thence through the filter 2 to the pump. Debris is carried into the container through the tube 5 on the air current and falls into the bottom 6 of the container. The debris is removed from zone 6 by a screw conveyor 7. The outlet of the screw conveyor has a hinged closure 13 which is biased into air-tight engagement with the outlet. The screw is capable of exerting sufficient force upon the debris to move the closure away from the outlet to discharge the debris. <IMAGE>

Description

SPECIFICATION Device at suction conveyors for continuous trans port of debris The present invention relates to conveyor arrange ments for the continuous transport of debris, in which a suction pump is provided to generate a partial vacuum in a filter container in order to transport debris thereto on a current of air and in which the filter container contains a filter through which the air is passed to the pump from a zone in which the debris is deposited by the air current and from which the debris is discharged.

In known conveyor arrangements of this type, the debris is generally discharged from the filter contain er by a cell feeder. The cell feeders used have however a poor feeding capacity and are quickly worn out.

According to the present invention there is pro vided a conveyor arrangement for the continuous transport of debris, comprising a filter container containing a filter device, a suction pump arranged to create an air current into the container through a conveyor tube, and thence through the filter device to the pump, the debris being carried into the filter container along the conveyor tube by the air current and fed, upstream of the filter device, into a dis charge zone of the container said discharge zone having an outlet, and a discharge device having an inlet connected to receive debris from said outlet, said discharge device comprising a screw conveyor having at its outlet end a closure which is biased into engagement with the outlet opening to seal the opening in an air-tight manner, and said screw conveyor including a feed screw for feeding debris from the filter container to the outlet of the screw conveyor with sufficient force to move the closure away from the outlet opening against the biasing force and to discharge the debris through said outlet opening.

The invention will now be described in more detail with reference by way of example to the accompany ing drawing, which illustrates diagrammatically a conveyor arrangement according to the invention.

The plant shown in the drawing comprises a filter container I (a so-called low-pressure vessel) with a replaceable filter device 2 of conventional type. At its upper end the filter container 1 is connected to a pump 4 via a conduit 3 and adjacent the lower end of the container is a conveyor tube 5 for debris, preferably in the form of powder or granules, e.g.

cement material. The pump 4 is of a size to generate such a vacuum in the filter container 1 that a powerful air current is obtained along the conveyor tube 5 and the debris if transported along said tube by the air current to a debris zone 6 down below in the filter container 1 (arrow R) while the air (arrow L) is passed through the filter device 2, which prevents the debris from flowing into the pump 4. The debris zone 6 beneath the filter device 2 has a decreasing cross-section in a downward direction and towards an outlet 17 which communicates with a discharging device 7 below. This device is designed as a screw conveyor comprising a cylindrical tube 8 with a feed screw 9 driven by a motor 10. Outlet 17 opens to tube 8.The outer diameter of the feed screw 9 is preferably only a few millimetres less than the inner diameter of the tube 8 and the motor operates the feed screw 9 such that it rotates with a speed of rotation substantially more than 100 rpm, preferably 800-1200 rpm, whereby the feed screw 9 attains a compressor effect.

The outlet 11 of the tube 8 is sealed in an air-tight manner by means of a sealing device 12. This device preferably comprises a cap 13, which is pivotally suspended about an axis 14 above the tube 8 in a support structure 15. The cap 13 is preferably suspended with its centre of gravity so positioned that the cap automatically returns to the position closing the tube 8. The cap 13 and/or the tube 8 may be provided with sealing rings (not shown) if this is necessary for obtaining sufficient sealing.

Since the feed screw 9 has a slightly smaller outer diameter than the inner diameter of the tube 8 and is driven to rotate at high speed, the screw may discharge the debris from the zone 6 with such a force that the debris pushes the cap 13 out of its sealing position. Furthermore, the feed screw feeds such large amounts of debris that the tube 8 is sealed beyond the cap 13, i.e. the discharging device 7 is sealed by means of the debris even if the cap 13 is open, which means that the discharging device forms a valve device permitting discharge of debris from the filter container 1 without affecting the vacuum therein.

In order to eliminate the risk of sticking of the debris in the zone 6, a guiding device 16 is provided in the filter container 1 for directing the flow of debris directly towards the outlet 17. The guiding device may comprise a downwardly directed end portion 18 of the conveyor tube 5.

The size of the discharging device in combination with the rotary speed is so selected that despite the compressor effect, the screw has such a capacity that the filter container 1 does not become filled with debris, which instead is discharged at the same rate as the debris is fed to the container 1. In this way it is ensured that the plant reaches a very high feeding capacity without the risk of damaging the filter device 2. The filter container 1 also has a float switch 19 for controlling a valve 20 such that the valve opens if the debris in the filter container 1 also has a float switch 19 for controlling a valve 20 such that the valve opens if the debris in the filter container 1 rises to a certain level because of shutdowns or for other reasons. By opening the valve 20, the vacuum in the filter container is relieved and the transport of debris thereto ceases. The float switch 19 and valve 20 may co-operate with a regulating device 21, e.g. a time relay or a microswitch of conventional type, regulating the valve 20 to close again after exposure container 1 is regenerated and the transport of debris to the filter container 1 re-established.

The plant described and illustrated in the drawing may of course vary with regard to the number of components and their design and position. Thus, the plant may comprise more than one pump device, filter device, feeding device and discharging device.

This may comprise more than one screw and sealing device of another type than a cap. The form of the apparatus is, in other words, not limited to the embodiment shown, but may vary within the scope

Claims

of the claims. CLAIMS

1. A conveyor arrangement for the continuous transport of debris, comprising a filter container containing a filter device, a suction pump arranged to create an air current into the container through a conveyor tube, and thence through the filter device to the pump, the debris being carried into the filter container along the conveyor tube by the air current and fed, upstream of the filter device, into a discharge zone of the container said discharge zone having an outlet, and a discharge device having an inlet connected to receive debris from said outlet, said discharge device comprising a screw conveyor having at its outlet end a closure which is biased into engagement with the outlet opening to seal the opening in an air-tight manner, and said screw conveyor including a feed screw for feeding debris from the filter container to the outlet of the screw conveyor with sufficient force to move the closure away from the outlet opening against the biasing force and to discharge the debris through said outlet.

2. A conveyor arrangement according to claim 1, further comprising a guiding device which directs debris entering the filter container along the conveyortube in a direction towards the discharging device.

3. A conveyor arrangement according to claim 2, wherein said guiding device comprises an end portion of the conveyor tube.

4. A conveyor arrangement according to any one of the preceding claims, wherein the feed screw is rotated at a speed such that said screw attains such a discharge capacity that the discharging device beyond the closure is sealed by means of the debris, when closure is moved thereby away from the outlet opening.

5. A conveyor arrangement according to any one of the preceding claims, wherein the size of the screw conveyor in combination with the rotary speed thereof is selected so that except compressor effect, the feed screw has such a capacity as to discharge the debris at at least the same rate as the debris is fed to the filter container.

6. A conveyor arrangement according to any one of the preceding claims, wherein a float switch device controls a valve device to interrupt the transport of debris into the filter container by interrupting the flow of air into the container.

7. A conveyor arrangement according to claim 6, wherein the valve device comprises a valve for relieving the partial vacuum in the filter container.

8. A conveyor arrangement according to claim 6 or 7, wherein the float switch device comprises a regulating device which after exposure of the float switch device again closes the valve device for re-establishing the transport of debris to-the filer container.

9. A conveyor arrangement according to claim 8, wherein the regulating device comprises a switch mechanism.

10. A conveyor arrangement substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.