GB2124576A

GB2124576A - Endless belt conveyor systems

Info

Publication number: GB2124576A
Application number: GB08320570A
Authority: GB
Inventors: Dennis Leslie Cook
Original assignee: Babcock Moxey Ltd
Current assignee: Babcock Moxey Ltd
Priority date: 1982-07-30
Filing date: 1983-07-29
Publication date: 1984-02-22
Also published as: GB2124576B; GB8320570D0

Abstract

An endless belt conveyor system has means for leading the belt (3) in its return run (3b) as roofing in proximity above a conveying run (3a) of the belt. The means (7b,11) supporting the belt serving as roofing may give it an arched configuration. Wall means (8) may close in the sides of the space between the two belt runs (3a, 3b) so that the material is conveyed in a closed passageway, which may be sealed by low-friction strips (7b, 9) on which edge regions of the two belt runs (3a, 3b) bear. At the loading region the two belt runs are spatially separated to accommodate feeding means which may comprise a continuously rotating transfer table, from which material falls onto the belt with a motion in the same direction as the belt. At the discharging region the belt runs are also spatially separated to accommodate receiving means which may comprise a continuously rotating table. <IMAGE>

Description

SPECIFICATION Endless belt conveyor systems This invention relates to endless belt conveyor systems for the continuous conveying of particulate material.

Endless belt conveyor systems are frequently required to convey material over substantial distances over open ground. The belt is almost invariably troughed and consequently rain collection by the belt may become a great nuisance unless the belt is provided with fixed roofing, the total expense of which increases with the distance involved.

An endless belt conveyor system according to the present invention has means for leading the belt in its return run as roofing in proximity above a conveying run of the belt.

Means supporting the belt serving as roofing may be arranged to give the belt an arched configuration.

Wall means may be provided to close in the sides of the space between the two belt runs to complete a closed passageway for material being conveyed.

The invention will now be described by way of example with reference to the accompanying drawings, in which Figure 1 is an elevation of an endless belt conveyor system.

Figure 2A is a view in section through the belt runs on the line Il-Il of Figure 1, Figure 2B is a sectional view similar to Figures 2A but showing a modified arrangement.

Figure 3 is a plan of the loading region 1 of the system of Figure 1.

Figure 4 is a plan of the discharging region 2 of the system of Figure 1, Figure 5 is an enlarged view of belt-tensioning apparatus part of Figure 1.

Figure 6 is a longitudinal sectional view to a larger scale of a saddle 43 represented in Figure 5, Figure 7 is a longitudinal sectional view to a larger scale of a tubular housing 46 represented in Figure 5, and Figure 8 is a longitudinal sectional view on a further enlarged scale of certain items represented in Figure 7.

With reference to Figures 1, 2A, 3 and 4 of the drawings, and endless belt conveyor system for the continuous conveying of particulate material, from a region 1 to a more or less distant region 2 includes an endless flexible belt 3, means 4 at the region 1 for loading the material onto the conveying run 3a of the belt, means 5 at the region 2 for receiving material discharged from the belt conveying run 3a and means for leading the return run 3b of the belt in the proximity above the belt conveying run 3a to serve as a roof over the material in conveyance on the belt conveying run 3a. The said conveying run may be horizontal over the greatest part of the distance, being caused to rise at a slight incline, however, as shown, as it reaches the discharge region 2.

As is usual with the conveying runs of belt conveyors, the weight of the material carried is taken through the belt by subjacent roller groups which are closely spaced along the length of the conveying run; for the sake of simplicity, only a few such groups 6 are indicated in Figure 1. As shown in Figures 1 and 2A, each roller group 6 consists of a pair of rollers symmetrically inclined to one another to give a troughed configuration to the belt in its conveying run. The return run 3b of the belt, where it is in proximity above the belt conveying run, is supported by a longitudinally extending central low-friction support strip 7a and at its edge regions by longitudinally-extending lateral low-friction support strips 7b.Preferably, as shown in Figure 2, lateral longitudinally-extending wall members 8, which might be bent sheeting or structural members of the supporting framework, close in the sides of the space in which the material is conveyed; the wall members extend between the lateral support strips 7b and lateral longitidulally-extending low-friction support strips 9 on which edge regions of the belt conveying run 3a bear downwardly. Thus there is provided a closed and sealed passageway for the material in conveyance.

The roofing-over of the belt conveying run 3a by the belt return run 3b tends to reduce or prevent the access of rain to material in conveyance or the nuisance of rain filling of a troughed belt not in use, and without the expense, which may be considerable for long conveyor travels, of fixed roofing. Moreover, in its return run in proximity above the conveying run the face of the belt that has previously carried the load is in position such that much of any material that may have clung to it and is subsequently shaken from its falls onto the conveying run and is thus recovered without effort, all of such material is recovered with the mentioned formation of the closed passageway. With the mentioned passageway, moreover, there will be no egress of dust particles from the conveying run or loss of material by spillage.

As shown in Figure 2A, the belt upper run support strip 7a is above the level of the lateral support strips 7b so that the belt return run assumes an inverted-trough or arched configuration by virtue of which rain may be thrown off and the passageway may accommodate a heap of material in conveyance on the belt while the wall members 8 have a relatively small depth. The overall width, moreover, may be made narrower if the return run is arched.

As would be evident to those concerned with belt conveyors, each subjacent roller group 6, supporting and troughing the laden belt, might well comprise an odd number of rollers, a central roller of horizontal axis being flanked by side rollers of axes inclined to the horizontal.

If the belt is a wide one, or, for the purpose of reducing friction on the supporting strips provided for the return run, in any event, the belt upper run may be partly or mainly carried by rollers subjacent thereto and if desired and as may be preferred conforming to an inverted-trough or arched configuration of the belt upper run. Figure 2B is a sectional view similar to Figure 2A but showing a relatively wide belt for a relatively large load cross-section: the subjacent roller group 6 supporting and troughing the belt conveying run 3a comprises a central roller 6a of horizontal axis flanked by a pair of side rollers 6b of axes inclined at 350 to the horizontal. In a known fashion the rollers are suspended in a "garland" with the aid of links 10.For the more effective confining of the material on the belt the lateral longitudinallyextending low-friction support strips 9 engaged by the edge regions of the belt have their bearing faces inclinded at an angle to the horizontal of 450, and greater than the inclination of the side rollers 6b . The belt return run 3b in proximity above the laden belt conveying run 3b, is supported in arched configuration mainly by roller groups, closely spaced along the length of the return run, each roller group comprising a pair of rollers 11, one to each side of the laden belt centre line, symmetrically inclined away from one another with axes inclined at 100 to the horizontal; the pair of rollers are supported in a frame 12 which extends from one side of the structure to the other.The belt return run is supported subsidiarily by lateral longitudinallyextending low-friction support strips 7b engaged by the edge regions of the belt return run, the strip bearing faces being horizonal in tranverse crosssection. It will be observed that the use of the supporting and troughing rollers 11 has rendered unnecessary any central return-run support strip such as that designated by the reference 7a in Figure 2A.

At the loading region 1 the means for loading the material onto the belt includes a continuously rotating transfer table 21 which is mounted on a vertical drive shaft adjoining the belt and which is of such size as to project substantially above a horizontal length 3c of moving troughed belt that is to receive on its upper surface the material to be conveyed, and which continues as the horizontal length of the belt conveying run 3a. In order to give accommodation to the parts of the loading means positioned above the belt length 3c the returning belt in the run 3b is led to pass partly round an idler pulley 22 bearing against the belt upper face, then at an upward inclination diverging from the belt length 3c to an upper return idler pulley 23 and then vertically downwardly to a lower return pulley 24, whence it enters the belt length 3c.

The transfer table 21 is arranged to be rotated in the sense such that the part extending above the belt run 3c moves in the same direction as the belt and two vertical curved guide plates 25 above the table confine material on the table to a path from a part of the table onto which it is deposited to fall from the table onto the belt run 3c with a component of motion in the direction of movement of the belt. The guide plates 25 are preferably continued as so-called skirt plates 26, extending vertically and running prallel to the belt, which assist in confining the fed material to the belt trough.A vertical pivoted deflector plate 27 is provided to make possible a bringing towards the centre line of the belt of material moving along its path adjacent the radially outer of the two guide plates 25, in case there should be an excess of such material arising from centrifugal force due to a possible high speed of table rotation. Vanes 28 on the table divide its surface into sectors.

At the discharge region 2 the belt at the end of its conveying run 3a is led around a head or driving pulley 29, past a snubbing pulley 30, then reversely and at a downward inclination to a tensioning pulley 31, thence again forwardly below means for receiving the material from the belt, then upwardly from a lower return pulley 32 to an upper return pulley 33 above the level of the material-recieving means, around which pulley 33 it turns into the return run direction. The materialreceiving means includes a continuously rotating transfer table 1 21 of vertical axis a part of which is positioned to receive material that falls from the belt, with a horizontal component of motion corresponding to the conveying movement of the belt, as the belt turns around the head pulley 29.

and the direction of table rotation is such that the table surface receiving the material has the same sense of horizontal motion as the material. The falling material trajectory depends on the belt speed and the relative positions of the head pulley and transfer table are arranged appropriately according to the belt speed.

The transfer table 1-21 serves to carry the material away from the discharge region 2; in the arrangement shown, it does so by feeding it onto a troughed horizontal length 1 03c of another belt conveyor arrangement, the belt 103 of which has a lower conveying run and an upper return run as does the belt 3; the conveying direction of the belt 103 is at right angles to that of the belt 3. The table 121 is arranged to feed the belt 103 exactly as the table 21 feeds the belt 3, with the aid of guide plates 125, skirt plates 126, a deflector 1 27 and vanes 128.

At the discharge region 2 scrapers 34 engage the belt 3 before and after it contacts the snubbing pulley 30, the belt face engaged being the lower face, i.e. the face (the "dirty" face) which has been carrying the conveyed material. Material dislodged by the scrapers 34 need not be a nuisance, for it falls onto or can be arranged to be gathered by the upper surface of the belt 3 as it travels from the tensioning pulley 31 to the lower return pulley 32, from which surface it can readily be diverted by deflecting scrapers (not shown) to fall into the troughed horizontal length 1 03c of the belt 103.

The depositing of the material on the transfer table 21 at the loading region 1 for the belt 3 takes place, in the arrangement shown, from a belt 203 in the same manner as the belt 3 deposits its material onto the transfer table 121.

The transfer tables 21 and 1 21 constitute means for feeding the belts 3 and 1 03 that do not require that the belts accelerate the material from rest and this is considered advantageous from the power requirement aspect and other aspects, more particularly when the belt speeds are to be high. The transfer tables 21 and 121 moreover constitute means for reciving material from the belts 203 and 3 without bringing the material to rest and this is also considered advantageous.

While each table is receiving its material it tends to receive from the impact thereof a driving torque that reduces the power required to rotate the table. The system of material transfer from one belt conveyor to another belt conveyor by means of transfer tables such as described, which do not have large height requirements, may substantially reduce the general height requirements at belt conveyor material transfer stations and the power consumed in preliminarily raising the material to be transferred. It is considered that, with equal belt speeds, different materials may be suited by different transfer table rotary speeds.

At the loading region 1 belt feeding means other than one with a rotating transfer table might be used if preferred for any reason such as a vibrating feeder, a belt feeder without an intermediate rotating transfer table or a chute or chutes debouching below the belt between the rollers 22 and 23 (Figure 1) and above the belt length 3c. At the discharge region 2 material receiving means other than one with a rotating transfer table might be used if preferred, for example, a chute arranged to receive the material falling from the end of the conveying run 3a as ths belt turns around the head pulley 29 (Figure 1) and leading the material to another belt conveyor or directly to a point of use.

The tensioning pulley 31 is part of belt tensioning apparatus which can be adjusted to vary the belt tension up to a maximum only. With reference to Figures 5 to 8, the frame 41 of the tensioning apparatus provides two parallel horizontal inverted channel saddles 43 which are supported thereon through captive roller bearings 44. The tensioning pulley 31 is mounted in bearings (not shown) which are carried by the two saddles 43. Bolted to each saddle 43 is a lug 40 which extends upwardly within the appropriate trackway channel 42 and which has a tapped bore for a threaded tensioning rod 45 extending parallel to the trackway channels 42; the lug and tensioning rod constitute a nut and lead screw arrangement for positioning the tensioning pulley when both tensioning rods are similarly rotated.The top tensioning rods 45 extend to respective tubular housings 46 at the end of the frame 41 remote from the belt runs to and from the tensioning pulley and each tensioning rod is there attached with the aid of welding to an end of a take-up bush 47 the other end 48 of which, whithin the appropriate housing 46, is flanged. A stack of disk sporing washers 49 surrounds the bush 47 within the housing 46 and acts between a fixed plate 50 to which the housing is attached and a collar and thrust washer 51 bearing on the bush flanged end 48.

The end of each housing 46 is closed by a cap plate 52 welded thereto and, in an aperture therein, holding a stud bolt 53 which can be rotated in the aperture without moving longitudinally. The end of the stud bolt within the housing carries an adjuster disk 54 formed with a diametral land 55 over which can fit a diametral groove 56 in the bush flanged end 48; with no tensioning of the belt by the pulley 31 the spring washers 49 urge the bush flanged end 48 against the adjuster disk 54 so that, should the stud bolt 53 be turned by a tool, the land and the groove can engage together and with such engagement effective the bush 47 and the tensioning rod 45 may be turned.

When both stud bolts 53 are turned in the direction such that the pulley 31 starts to put tension in the belt there arise longitudinal reaction forces in the two tensioning rods 45 which are initially insufficient to compress the washers 49 further: however, with increasing tensioning the said reaction forces compress the said spring washers further and increasingly and the bush flanged ends 48 moves increasingly away from the adjuster disks 54; when the tensioning reaches a certain value the bush flanged ends 48 are so distanced from the adjuster disks 54 that there is no longer engagement between the grooves 56 and the lands 55, and further rotations of the stud bolts 53 are ineffective to increase the belt tensioning further. The compression of the disk spring washers to allow the disengagement is calculated to correspond to the tension required in the belt, thereby to provide a convenient means for setting the belt tension.

Claims

1. An endless belt conveyor system having means for leading the belt in its return run as roofing in proximity above a conveying run of the belt.

2. A belt conveyor system as claimed in Claim 1, wherein means supporting the belt serving as roofing are arranged to give the belt an arched configuration.

3. A belt conveyor system as claimed in Claim 2, wherein the belt serving as roofing is supported by pairs of rollers spaced along the belt, each pair comprising rollers inclined away from one another

4. A belt conveyor system as claimed in any of Claims 1 to 3, wherein wall means close in the sides of the space above the belt conveying run and below the belt serving as roofing to complete a closed passageway for the material being conveyed.

5. A belt conveyor system as claimed in Claim 4, wherein lower lateral low-friction strips are provided which engage edge regions of the belt conveying run, upper lateral low-friction strips are provided which engage edge regions of the belt serving as roofing, and the wall means extend between the upper and lower low-friction strips to seal the said closed passageway.

6. A belt conveyor system as claimed in any of Claims 1 to 5, wherein at a loading region of the belt conveyor system pulleys are arranged to lead the belt in its return run firstly at an upward inclination sufficiently away from proximity to the belt moving in the conveying direction to accommodate belt feeding means between the upper and the lower belt runs and then downwardly to a pulley aligned with the belt in its movement below the feeding means.

7. A belt conveyor system as claimed in Claim 6, wherein the belt feeding means includes a rotary table a part of which extends into the space between the upper and lower belt runs and is arranged to let material fall therefrom onto the belt with a component of motion in the direction of movement of the belt.

8. A belt conveyor system as claimed in Claim 7, wherein the feeding means includes guide plates arranged for guiding material on the plate as the plate rotates in a curved path terminating in the direction of the movement of the belt.

9. A belt conveyor system as claimed in Claim 8, including a vertical pivoted deflector plate arranged to make possible a bringing towards the centre line of the belt a material adjacent the radially outer guide plate.

10. A belt conveyor system as claimed in Claim 8 or Claim 9, wherein the guide plates are continued as skirt plates assisting in confining the material to the belt trough.

11. A belt conveyor system as claimed in any of Claims 7 to 10, wherein vanes on the table divide its surface into sectors.

12. A belt conveyor system as claimed in any of Claims 1 to 11, wherein at a discharge region of the belt conveyor system pulleys are arranged to lead the belt, after it has discharged material, at a reverse and downward inclination, then again forwardly and below means for receiving the material from the belt and then upwardly to a level above the said receiving means.

13. A belt conveyor system as claimed in Claim 12, wherein the material receiving means includes a rotary table a part of which extends into the space between the upper and lower belt runs to receive material discharged from the belt and is arranged to be rotated so that the said part has the same direction as the horizontal component of the motion of the material falling onto the table.

1 4. A belt conveyor system as claimed in Claim 13, wherein the rotary table receiving the material is arranged to carry material falling on it away from the space between the upper and lower belt runs and to let the material fall onto a material receiving length of another belt conveyor.

1 5. A belt conveyor system as claimed in Claim 14, wherein scrapers are provided to engage the lower face of the belt as it runs downwardly and reversely after it has discharged material and deflecting scrapers are provided to divert so as to fall onto the material-receiving length of the second-mentioned belt conveyor material dislodged by the first-mentioned scrapers and falling onto or gathered by the belt running beneath the transfer table.

1 6. A belt conveyor system as claimed in any of Claims 1 to 15, wherein belt tensioning apparatus includes a nut and lead screw device for positioning a belt-tensioning pulley, the lead screw means of which are resiliently mounted and arranged to effect when the belt tension exceeds a certain value a disengagement of clutch means through which the lead screw means may be further turned.

1 7. A belt conveyor system substantially as hereinbefore described with reference to the bccompanying drawings.