GB2155885A - Conveyor system - Google Patents

Abstract

A conveyor for loose bulk material has a plurality of individually operable main conveyor units (1, 2, 3) disposed in alignment with each other to provide a main conveyor path, with transverse discharge conveyors (11, 12, 13) located between adjacent main conveyor units, each transverse conveyor having a detector (21, 22, 23) operable to inhibit the operation of the immediately upstream main conveyor unit in the event that it detects a build-up of more than a predetermined amount of material on the associated transverse conveyor, if, and only if, the immediately adjacent downstream main conveyor is not operating. <IMAGE>

Description

SPECIFICATION Conveyor system This invention relates to a conveyor system for conveying loose bulk material of a non-free-flow- ing nature from a common source to a plurality of individual outlet positions (which may be batch weighing and/or packaging stations). The material may, for example, consist of a substance or product of a dry granular or particulate nature or of discrete portions or pieces capable of being fed along the conveyor system as a bulk flow.

In processes handling degradeable material, for example certain foodstuffs, it is desirable to be able to control the rate at which the material is fed along the conveyor system according to demand, so that it is sufficient to meet, but does not exceed, the requirements at the various outlet positions, in order to ensure that the material is used in order of supply without recirculation or long-term storage in the system.

An object of the invention is to provide a conveyor system capable of fulfilling the above requirements.

According to the invention a conveyor system comprises a plurality of individually operable main vibratory conveyor units disposed in alignment with each other to provide a main conveyor path, and between each pair of said conveyor units a discharge conveyor individually operable to carry the material transversely from the main conveyor path to a respective outlet position, each drive imparted to the flow of material by a main conveyor unit being sufficient to cause the material to be passed across the intervening part of the surface of the respective discharge conveyor on to the next main conveyor unit, and the system including, for each transverse conveyor, a detector for monitoring the amount of material on that conveyor, and control means operable in response to an output from the detector to inhibit the operation of the immediately adjacent upstream main conveyor unit in the event that the detector detects a build-up of more than a predetermined amount of material on the associated transverse conveyor. Preferably the control means is arranged to inhibit the operation of the immediately adjacent upstream main conveyor unit, in response to the detector if, and only if, the immediately adjacent downstream main conveyor unit is not operating.

The final main conveyor unit of the system may also feed a transverse conveyor operable to carry material to a respective outlet position, and having a detector for arresting said final main conveyor unit on detection of a build-up of more than a predetermined amount of material on the associated transverse conveyor.

Alternatively the final main conveyor unit may be arranged to feed material directly to a final outlet position, and have associated with it control means for stopping the operation of the unit in the event that there is no demand for material at said outlet position.

Preferably each of the transverse conveyors is a vibratory conveyor and is similarly controlled so that each is actuated only when there is a demand for material at the respective outlet position.

The invention provides a compact conveyor system having a relatively simple control arrangement which ensures that the flow of material is maintained at a value which is adequate to meet the demands of the various outlet positions, without excessive build-up of material in the system in the event of a drop in demand due,for example,to a stoppage of a machine or machines receiving the material at one or more of the outlet positions.

One conveyor system in accordance with the invention will now be described by way of example with reference to Figures 1 and 2 of the accompanying schematic drawing in which Figure 1 represents a plan view of the system, and Figure 2 represents a side view of part of the system.

The system is designed to carry loose irregularly shaped material such as potato crisps, and comprises a series of main vibratory conveyor units 1, 2, 3 disposed in alignment with each other to provide a main conveyor path along which the material is arranged to be fed, in operation of the system, in the direction indicated by the arrow. An infeed whether it be a conveyor or any other feed, shown diagrammatically at 4, feeds material on to the conveying surface of the first of the conveyor units.

The infeed device could, for example, take the form of a storage conveyor which may be constructed as described in co-pending application No.

8320688, but other forms of storage conveyor could alternatively be employed.

The conveying surface of each of the main conveyor units 1, 2, 3 is generally planar but is inclined slightly upwards in the direction of material flow as shown in Figure 2, and is provided at each side with upstanding side walls 5 to prevent spillage of material being conveyed. At the downstream end of each conveyor unit 1, 2, 3 there is disposed a transverse vibratory conveyor 11, 12, 13 having a conveying surface slightly lower than that of the adjacent end of the respective main conveyor unit, but, in the case of the conveyors 11, 12 slightly higher than that of the inlet end of the immediately adjacent downstream main conveyor 2, 3 respectively.

The individual main conveyor units 1, 2, 3 and the individual transverse conveyors 11, 12, 13 are all separately energisable by separate electro-mechanical drive units represented diagrammatically at D1, D2, D3 and D11, D12 and D13 respectively, which can be of known kind operable to cause material on their conveying surfaces to be fed in the appropriate direction.

Each of the transverse conveyors 11, 12, 13 is arranged to feed material to respective weighing packaging or like units 6, and the respective drive unit D11, D12, D13 is arranged to be de-energised when the operation of the associated weighing packaging unit is stopped or for any other reason the demand for material by the unit ceases.

The part 7 of each of the transverse conveyors 11, 12, 13 on to which material is deposited by the immediately upstream main conveyor is, in the arrangement illustrated of greater width than the parts leading to the respective weighing/packaging units 6, the material being funnelled into the narrower parts of the conveyors 11, 12, 13 by inciined wall sections 8 as shown, the inlet end of the main conveyors 2, 3 being widened to extend beneath the respective funnel portion of the transverse conveyors 11, 12, with the respective part 5.1 of the adjacent side wall being angled accordingly. However it is not necessary for the width of the transverse conveyors to decrease, and for some applications they could remain the same width throughout their length.

A wall 9 at the upstream end of each transverse conveyor 11, 12, 13 prevents spillage at that end, and in the case of the final conveyor 13 the wall is continued around the adjacent side of the conveyor as at 9.1.

The downstream edge of the conveying surface of each main conveyor 1, 2, 3 is inclined slightly as shown at 10 to produce a more even distribution across the width of the respective transverse conveyor 11, 12, 13.

The disposition of the various conveyor surfaces and the drive imparted to the main conveyor units 1, 2 is such that in use, with all the units 1, 2, 3 operative, material is pushed across the intervening parts 7 of the surfaces of the transverse conveyors 11, 12, on to the conveying surfaces of the immediately adjacent downstream main conveyor units 2, 3 respectively, and if the transverse conveyors are operating some of the material will be diverted by them to the respective weighing/packaging units 6.

Associated with each of the transverse conveyors 11, 12, 13 there is a photo-detector 21, 22, 23 disposed so as to monitor the quantity of the material at a position on the respective conveyor surface. Each photo-detector forms part of a control circuit 15 which is arranged to open a switch S1, S2, S3 in the circuit controlling the energisation of the immediately adjacent upstream main conveyor unit 1, 2, 3 respectively when the material sensed by the photo-detector on the associated transverse conveyor builds up to more than a predetermined value, as determined by the setting of the detector.

Each of the switches S1, S2, has, in parallel with it, a further switch S10, S20 respectively controlled in response to the operation of the drive circuit of the next downstream main conveyor unit, and arranged to be opened when the drive unit of the associated main conveyor unit is stopped for any reason.

Should there be no demand for material on one of the transverse conveyors 11, 12, 13, due for example to stoppage of the associated weighing/ packaging unit 6, the drive unit D11, D12, D13 as appropriate operating that transverse conveyor will be de-energised, thus stopping the conveyor. This will cause a build-up of material on the surface of the conveyor near to the inlet end, at a region ad recent the photo-detector, due to material being urged along it by the force of material fed from the immediately adjacent upstream main conveyor.

If the stoppage is prolonged the build-up will cause the detector to generate a signal resulting in the opening of the switch S1, S2, S3 in the drive circuit of the adjacent upstream conveyor unit 1, 2 or 3 respectively.

In the case of the conveyors 1, 2 this will have no immediate effect, as long as material is being called for by the final transverse conveyor 13.

However should a build-up occur on this final conveyor 13, a signal from the photo-detector 23 will cause the associated main conveyor 3 to be stopped. Accordingly the switch S20 will be opened, and if the switch S2 has remained open due to the build-up of material on the transverse conveyor 12, the main conveyor unit 2 will be stopped. Similarly if the main conveyor unit is stopped, the switch S10 will be opened and provided the switch S1 is also open, due to a build-up of material on the transverse conveyor 11, the main conveyor unit 1 will also be stopped.

However if a main conveyor unit 3, 2 has been stopped, and there is no build up of material on the respective transverse conveyor 12, 11 because its weighing/packaging unit 6 is stiil calling for material, the immediately adjacent upstream conveyor 2, 1, as appropriate, will continue to function.

A further photo-detector 41 at the upstream end of the initial main conveyor 1 is arranged to monitor the amount of material on this conveyor, and, on detecting an excessive build-up of material, is caused to generate a signal which is fed to the control circuit of the infeed device 4 and prevents further material being fed on to the conveyor 1, until such time as the latter is restarted, and the build-up is no longer detected.

It will be seen that the system operates with a very simple control system, and the need for additional material detectors disposed to detect the build-up of material along the main conveyor path is avoided.

Although the system described used photo-detectors, which can be of any suitable known form, other forms of detectors, for example those utilising mechanical probes and micro switches could alternatively be employed. In addition the system could utilise a greater number of main and transverse conveyors if required. Other modifications are clearly possible.

Claims (9)

1. A conveyor system comprising a plurality of individually operable main vibratory conveyor units disposed in alignment with each other to provide a main conveyor path, and between each pair of said conveyor units a discharge conveyor individually operable to carry the material transversely from the main conveyor path to a respective outlet position, each drive imparted to the flow of material by a main conveyor unit being sufficient to cause the material to be passed across the intervening part of the surface of the respective discharge conveyor on to the next main conveyor unit, and the system including, for each transverse conveyor, a detector for monitoring the amount of material on that conveyor, and control means operable in response to an output from the detector to inhibit the operation of the immediately adjacent upstream main conveyor unit in the event that the detector detects a build-up of more than a predetermined amount of material on the associated transverse conveyor. Preferably the control means is arranged to inhibit the operation of the immediately adjacent upstream main conveyor unit, in response to the detector if, and only if, the immediately adjacent downstream main conveyor unit is not operating,

2.A conveyor system according to Claim 1 wherein the control means is operable to inhibit the operation of the immediately adjacent upstream main conveyor unit in the event that the detector detects a build-up of more than a predetermined amount of material on the associated transverse conveyor if, and only if, the immediately adjacent downstream main conveyor unit is not operating.

3. A conveyor system according to Claim 1 or 2 wherein the final main conveyor unit of the system is also arranged to feed a transverse conveyor operable to carry material to a respective outlet position, and having a detector for arresting said final main conveyor unit on detection of a build-up of more than a predetermined amount of material on the associated transverse conveyor.

4. A conveyor system according to Claim 1 or 2 wherein the final main conveyor is arranged to feed material directly to a final outlet position, and has associated with it control means for stopping the operation of the unit in the event that there is no demand for material at said outlet position.

5. A conveyor system according to any preceding Claim wherein each of the transverse conveyors is a vibratory conveyor and is similarly controlled so that each is actuated only when there is a demand for material at the respective outlet position.

6. A conveyor system according to any preceding Claim wherein each detector is a photo-detector.

7. A conveyor according to Claim 6 wherein each photo-detector forms part of a control circuit and is arranged to open a switch in the circuit controlling the energisation of the immediately adjacent upstream conveyor when it senses that the material on the respective transverse conveyor exceeds a predetermined height.

8. A conveyor according to Claim 7 wherein each of said switches has, in parailel with it, a further switch controlled in response to the operation of the next downstream main conveyor unit, and arranged to open when said next downstream main conveyor unit is stopped.

9. A conveyor system substantially as shown in and as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawing.