GB2170771A

GB2170771A - An elevator conveyor

Info

Publication number: GB2170771A
Application number: GB08503139A
Authority: GB
Inventors: Ronald Ernest Pace
Original assignee: Simon Carves Ltd; Carves Simon Ltd
Current assignee: Simon Carves Ltd; Carves Simon Ltd
Priority date: 1985-02-07
Filing date: 1985-02-07
Publication date: 1986-08-13
Also published as: GB8503139D0

Abstract

An elevator-conveyor of the kind including a pair of flexible belts disposed face-to-face and between which material is introduced to be conveyed along a working length in a vertical or near vertical direction, includes where the material is introduced, a paddle wheel impeller (13) and at least one screw conveyor (12) which combine to draw the material into an entrainment zone between the belts. There are means to cause the screw conveyor and the paddle wheel impeller to effect different relative rates of conveyance by operating at different speeds or by the shape and configuration of the screw flight, in order to optimise the rate of feed according to the characteristics of the material being conveyed. <IMAGE>

Description

SPECIFICATION An elevator-conveyor This invention relates to an elevator-conveyor designed to convey bulk material over a pre-determined path, at least a portion of which passes in a vertical or near vertical direction, the bulk material being conveyed between a pair of juxtaposed belts which, in the vertical or near vertical direction, are pressed towards one another and against the interposed bulk material so as to enclose same.

Such an elevator-conveyor which is described in British Patent No. 1319738, can be employed as a static installation in a silo or the like or can be included in a mobile device such as, for example a ship's unloader in which case the feed or input end of the elevator-conveyor is to be introduced into a confined region such as, for example, a ship's hull.

It is a particular object of this invention to provide, in such an elevator-conveyor, a feed mechanism which can readily introduce material to be conveyed into the area between the belts in a feed entraining zone thereof.

According to the present invention there is provided an elevator-conveyor for conveying bulk material over a pre-determined path, at least a working length of which is in a vertical or near vertical direction and comprising a pair of continuous flexible belts mounted so that the front surfaces thereof face each other during passage along said working length, drive means for moving the belts at a common speed, means for feeding bulk material between the front surfaces of the belts at an input end of said working length, means for urging the front surfaces of the belts towards each other and against the bulk material interposed therebetween, said feeding means including at least one screw conveyor and a paddle wheel impeller cooperating to collect said bulk material and project same upwardly between the front surfaces of the belts, means being provided to cause said screw conveyor and said paddle wheel impeller to effect different relative rates of conveyance.

Some embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side elevation of a ship's unloader incorporating an elevator-conveyor made in accordance with the invention; Figure 2 illustrates schematically, in vertical section, a feed mechanism for the elevator-conveyor; Figure 3 is a section taken on line Ill-Ill of Figure 2; and Figures 4 and 5 illustrate alternative forms for a part of the feed mechanism.

As seen in Figure 1, the elevator-conveyor includes an elevator column 1 which is provided at a lower end thereof with a feed mechanism 2 and is pivotally articulated at an upper end thereof to a conveyor boom 3. The boom 3 is pivotally articulated to a centrai column 4 which is rotatably mounted via a turntable 5, on a portal 6. The portal 6 is movable along a quay 7 by means of carriages 8 on rails 9. Hydraulic cylinders A and B are provided for manoeuvring the column 1 and boom 3 to different configurations for locating the feed mechanism 2 in a position to receive bulk material to be conveyed.

Referring now to Figures 2 and 3, it will be seen that the principai conveying members within the elevator-conveyor are comprised by a pair of driven endless flexible belts 10 and 11 which are juxtaposed face-to-face over a working stretch throughout which bulk material is conveyed by being trapped between the belts, means as described in BP 1319738, being provided to force the opposed edges of the two belts together.

The material is introduced between the belts at the lower end of the column 1 by means of a pair of screw conveyors 12 which when the feeding mechanism 2 is placed on or below the surface of the material serve to collect same onto a paddle wheel impeller 13 which raises the material and projects it, constrained between opposed guide plates 14, into the entraining zone between the belts.

It has been discovered that for different materials the relationship between the conveying performances of the screw conveyor and the paddle wheel impeller should be made variable in order to optimise the combined feeding action. It is therefore proposed in accordance with one embodiment of this invention to drive the screw conveyors from a separate source from that driving the paddle wheel impeller, and to select the rotational speed of the screw conveyors to be different from that at which the paddle wheel impeller is driven thus to provide differential rates of conveyance between the two devices. The differential drives to the screw conveyors and paddle wheel impeller can be provided in any suitable manner, for example, by two separate motors or by one motor differentially geared to the two devices.For the purpose of illustration, the paddle wheel impeller is shown as being rotatably mounted on a shaft 15 which is positioned concentrically within a shaft 16 upon which the screw conveyors are mounted.

With this arrangement a more effective conveyance of certain materials onto the paddle wheel impeller will be achieved.

In some cases, a single screw conveyor may be provided to gather material onto the paddle wheel impeller, and, whiist the screw conveyors have been shown for simplicity, each having a single flight, two or more flights may be provided, for example, for the purpose of avoiding the introduction of tramp iron and other foreign objects between the belts, or for the efficient handling of certain materials.

It is considered that differential speeds of rotation may be available to suit the characteristics of the material being conveyed.

Referring now to Figures 4 and 5, two modified forms of conveyor screw flight are illustrated and will be described. Whilst differential conveyance may be provided, by differential speeds of rotation, alternatively this may be achieved by driving the conveyor 12 and the paddle wheel impeller 13 on a common shaft at the same speed, and by adopting so-called ribbon screw flights as indicated at 12' in Figure 4 where a free space exists between the root of the flight and the supporting shaft. The depth of the ribbon is selected to provide the appropriate rate of conveyance. Here, the depth can vary along each conveyor section thus to vary the rate of conveyance as the material approaches the paddle wheel impeller. Furthermore, the pitch of the ribbon flight can vary to produce the same effect.

Instead of the ribbon 12' a plurality of individual blades can be provided as shown at 12" in Figure 5. To achieve a variable rate of conveyance the blades 12" may be rotatable at their roots in a manner similar to that used to vary the pitch of turbine blades, i.e. a mechanism within the central supporting shaft may be provided to rotate the blades to the required pitch even when the shaft is rotating.

Several other methods of effecting differential rates of conveyance, are possible as might readily occur to one skilled in the art. For example, the relative diameters of the conveyor flights or blades and the paddle wheel impeller can differ and these will be determined during the development of practical applications of this system in different environments and with different materials.

An additional feature which may be expedient in some cases is for the flight or flights of the conveyors to be notched in their peripheral regions for the purpose of breaking up compacted materials.

Claims

1. An elevator-conveyor for conveying bulk material over a predetermined path, at least a working length of which is in a vertical or near vertical direction and comprising a pair of continuous flexible belts mounted so that the front surfaces thereof face each other during passage along said working length, drive means for moving the belts at a common speed, means for feeding bulk material between the front surfaces of the belts at an input end of said working length, means for urging the front surfaces of the belts towards each other and against the bulk material interposed therebetween, said feeding means including at least one screw conveyor and a paddle wheel impeller cooperating to collect said bulk material and project same upwardly between the front surfaces of the belts, means being provided to cause said screw conveyor and said paddle wheel impeller to effect different relative rates of conveyance.

2. An elevator-conveyor according to Claim 1, wherein said means to effect different relative rates of conveyance comprises separate drive means for said paddle wheel impeller and said screw conveyor such that they are driven at different relative speeds.

3. An elevator-conveyor according to Claim 2, wherein said paddle wheel impeller and said screw conveyor are mounted on concentric separately driven shafts.

4. An elevator-conveyor according to Claim 1 or Claim 2, wherein the diameter of the conveyor flight is different from that of the paddle wheel impeller.

5. An elevator-conveyor according to Claim 1, wherein said means to effect different relative rates of conveyance comprises a ribbon screw flight on said screw conveyor with a free space between the root of the flight and a supporting shaft, the depth of ribbon being such as to effect a selected rate of conveyance thereby in relation to that effected by said paddle wheel impeller.

6. An elevator-conveyor according to Claim 5, wherein the depth of said ribbon varies along the length of the screw conveyor to vary the rate of conveyance as the material approaches the paddle wheel impeller.

7. An elevator-conveyor according to Claim 5, wherein the pitch of the ribbon flight varies along the length of the conveyor to vary the rate of conveyance as the material approaches the paddle wheel impeller.

8. An elevator-conveyor according to Claim 1, wherein said means to effect different relative rates of conveyance comprises a plurality of individiual radial blades arranged to make up a screw conveyor flight.

9. An elevator-conveyor according to Claim 8, wherein said blades are rotatable about their indi viduai radial axes, to vary the pitch of said conveyor flight.

10. An elevator-conveyor according to any preceding claim, wherein the flight of said screw conveyor is notched in its peripheral region such as to break up compacted materials.

11. An elevator-conveyor substantially as herein described with reference to and as illustrated in the accompanying drawings.