BULK MATERIALS CONVEYOR
The invention described herein relates to a bulk materials conveyor featuring an endless conveyor belt provided with an upper and a lower section. The bulk material is loaded onto the top of the lower section of the belt, referred to as the load section.
State of the art
The existence of a method and a conveyor of this type for transporting ore and similar bulky materials is already known from Canadian patent 1.045.073. In this case, the material is conveyed on the top of the lower section of a belt conveyor, the section running in a water-filled trough. Sludge from the ore is carried with the material itself to the end of the conveyor where both the material and sludge are scraped off.. The spillage incurred in the operation is thus removed as sludge together with the ore from the top of the lower section.
Technical problem
A conveyor of this type cannot be used for conveying cement, chips, bark, grain, sand, chemicals and similar materials. The spillage of bulk materials of this type from the conveyor is extremely liable to cause disruption in operation. f
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Solution of technical problem •
The conveyor which is the subject of this invention is constructed as specified in one of the following patent claims to permit the transport of the aforementioned bulk materials without spillage. As explained -in the description of the principal distinguishing feature of this invention, the conveyor belt is supported by an arrangement of supports consisting of a support device for a central section of the belt and of belt support surfaces inclined relative to each other and to the central section of the belt.
The following is a description of a number of conveyor arrangements as envisaged by the invention. The description refers to the appended drawings, of which:
Fig. 1 is an elevation of the conveyor as constructed for the transport of bulk' materials on the lower section of the belt,
Fig. 2 shows the bulk material discharge device, as section B-B in Fig. 1,
Fig. 3 shows another device for discharging bulk materials, as section D-D in Fig. 7,
Fig. 4 shows an arrangement of the belt drive pulleys and intermediate drum- for transferring spillage from the load section to the discharge device, as section A-A in Fig. 1,
Fig. 5 illustrates the method of directing the spillage to the top of the load section of the belt, as section C-C in Fig. 1,
Fig. 6 shows the conveyor totally enclosed.
Figs. 7 and 8 show a belt for conveyor spillage.
Fig. 9 shows a section through the drive end of the conveyor, also showing the spillage conveyor,
Fig. 10 shows a design of belt support device featuring rubber profiles for both the upper and lower sections.
Fig. 11 shows the support illustrated in Fig. 10 viewed from above in the direction of the arrow F,
Fig. 12 shows, in the case of the supports illustrated in Fig. 10, how air is blown in between the rubber profiles supporting the belt, as viewed from above in the direction of the arrow G, f GϊIFI
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Fig. 13 shows a design of belt support incorporating V-belts and.
Fig. 14 is an elevation of the support illustrated in Fig. 13.
The present invention eliminates the spillage which is characteristic of earlier types of conveyors, while also eliminating the propagation of dust,by virtue of the fact that the bulk material 1 is carried on the lower section 2 of the belt, the lower section thus being the load section. The upper section 3 is the return section.
The bottom 4 of the upper section 3,which was the top 5 of the lower section 2 when conveying the bulk material 1,is the surface which may cause spillage. The spillage is directed towards the centre of the lower section 2 i.e. the top 5 of the load section by means of baffle plates 6 .
The conveyor belt may consist either of a smooth belt supported on multi-roller idlers 7, or of a belt of the carrier type. The belt may also incoporate raised sides so that the belt itself forms a trough.
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Conveyor belts are inevitably subject to the risk of running off centre on their idlers. This risk may be particularly high when the lower section is the load section as in the prevent invention.
To .improve the centering of the belt and, thereby, counteract misalignment, the idler stands 7 which carry the belt may be supported on rubber feet 8. In the event of uneven "belt loading, each foot will act more or less as a pivot to correct the centering of the belt.
When conveyor belts of the carrier type are used, almost vertical rising belts may be installed. This is a significant advance since, hitherto, it has been invariably impossible to use this type of belt due to the risk of spillage accumulating on the carr¬ iers, resulting in considerable operating problems. Since the present invention eliminates the accumulation of spillage on the belt, it also renders the operation of conveyors with carrier type belts more reliable.
Figs. 7, 8 and 9 illustrate the incorporation of a small additional conveyor 19 in the drive end of the main conveyor for collecting the spillage 9. The spillage conveyor consists of two rubber profiles 20 and 21 which function both as sealing and drive elements for the belt of the additional conveyor 19 between the main conveyor belt and its drive ulle s 22. The
belt of the additional conveyor 19"," consisting of a rubber sheet 23, which collects the spillage from the upper section 3 and transfers it to the top 5 of the- bottom section 2 of the main- conveyor belt runs between the profiles 20 and 21.
Fig. 1 shows a belt cleaning device 12 consisting of a cleaning section 24 with profiles 25 connected to the bottom 4 of the upper section 3 of the belt in order to remove the spillage from the bottom 4 of the upper section 3.
In Figs. 7, 8 and 9, the belt cleaning device 12 is shown in the form of vibrators 27 acting on the top 26 of the upper section 3 of the belt. The figure also shows the manner in which the sheet rubber belt 23 of the small additional conveyor 19 mounted underneath the top section is fitted with a support bar 28.
In many applications, it is preferable to provide the main section of the conveyor as described in the invention with an enclosure 29 attached to the support frame 30 on which the conveyor is mounted. For reasons of safety, this enclosure is fitted with a vent opening 31.
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The other end of the .conveyor belt runs on a tensioning pulley 32.
Alternative designs of support devices for the conveyor belt are shown in Figs. 10-12. The spillage-free belt conveyor may also be constructed so that the bottom section 2 carries the load 1, supported in a trough provided with a first set of rubber profiles 33 with a moulded top surface of an anti-friction material aligned in the direction of travel of the conveying belt. The upper section 3 is supported by a second set of rubber profiles 34 which also serve to form the conveying belt into a trough shape so as to discharge the spillage through a slot 43 to the bottom section 2. The introduction of a flow of air 36 (as shown by the arrows in Fig. 12) at a pressure above atmospheric between the first set of rubber profiles 33 supporting the bottom section 2 creates an air film between the conveyor belt and the first set of rubber profiles 33. The air, which is supplied through pipe 35, flows along the entire length of the conveyor belt and is discharged through vent opening 37 into the adjacent channel between the first set of rubber profiles before being returned all the way to the next vent opening and being discharged finally through the vent opening in the outermost rubber profile.
Figs. 13 and 14 show a design of support device for the conveyor belt which is also intended to counteract the tendency of the belt to sag between idler stands, thereby rendering it susceptible to damage by heavy or sharp pieces of material. The invention is intended to eliminate this tendency by replacing the middle rollers in the idler stands by V-belts with a vulcanised high-friction coating, thereby affording a simple means of supporting the conveyor belt and eliminating the tendency to sag. The proposed V-belt may also make a positive contribution to driving the conveyor belt, simultaneously reducing the tensile load on the belt. This feature should facilitate the use of simple, conventional conveyor belts in applications involving the handling of heavy materials on long, inclined conveyors. At present, highly expensive steel cord belts are usually used for this purpose.
The support device shown in Figs. 13 and 14 consists of V-belts 38 with a vulcanised friction coating running on numerous small, simple support wheels 39. The conveyor illustrated in Fig. 13 is shown in Fig. 14 with pulleys 40, which may be driven, at one end. The return section of the V-belt runs on a support profile 41. Pulleys 42, at the other end of the conveyor, should preferably be provided with an adjustable mounting to enable the belt tension to be correctly adjusted.