GB2024140A

GB2024140A - Apparatus for discharging material from a heap

Info

Publication number: GB2024140A
Application number: GB7922485A
Authority: GB
Original assignee: Pohlig Heckel Bleichert Vereinigte Maschinenfabriken AG
Current assignee: Pohlig Heckel Bleichert Vereinigte Maschinenfabriken AG
Priority date: 1978-06-28
Filing date: 1979-06-28
Publication date: 1980-01-09
Also published as: AU4842779A; GB2024140B; CA1103605A; AU533965B2

Abstract

Apparatus for discharging material from a heap has a movable bridge for extending across the heap and a discharge conveyor which comprises two endless, parallel traction members 1 extending parallel to the bridge and spaced conveyor members 3 each fixed to each of the two traction members 1; each conveyor member 3 has a generally horizontal, rearwardly-projecting carrying surface 31 which is adjacent the following conveyor member 3 when the conveyor members are in the section of the conveyor which discharges the material, and an opening is left on at least one side for the entry of material. When the conveyor members 3 reach the star wheel 6, they are swung up and over and the material slides off the carrying surfaces 31 onto another conveyor 5. Guide walls 4 are preferably provided projecting forwardly and outwardly at an angle to the direction of conveyance P, the guide walls acting to sweep the material on to the carrying surface 31. <IMAGE>

Description

SPECIFICATION Apparatus for discharging material from a heap Background of the Invention The present invention relates to apparatus for discharging material from a heap of bulk material, for instance in a plant for storing material for long periods or only temporarily, or in a mixed bed plant.

The apparatus has a moveable bridge for extending across the heap, and a discharge conveyor having two endless, parallel traction members, for instance pivoted-link chains, and spaced conveyor members connected to the traction members.

In general terms, such apparatus is known, and can be used for discharging bulk materials of greatly varying particle sizes. A particular problem arises when the material is sensitive to friction or wear or is of very fine grain size. With such materials, for intance coal or fertilisers, it is desirable to suppress gross rolling movement as much as possible and also to avoid letting the material fall significant distances, so that the particles are not worn away or fragmented too much and so that not too much dust is formed.

The Invention The invention provides apparatus as set forth in Claim 1 and plant as setforth in Claim 10. Claims 2 to 8 set forth preferred features of the invention.

Using the apparatus of the invention, the material can be picked up uniformally at the base of the heap and no rolling movement occurs within the mass of material when it is resting on the carrying surfaces.

In the section of the conveyor which discharges the material, which will normally be straight, the carrying surfaces form a practically unbroken moveable platform on which the material rests, and the space above the carrying surfaces is accessible from the side so that the material can pass unhindered onto the carrying surfaces.

In the preferred construction of Claim 2, the spaces which contain the material are separated from one another by the rear walls and are of cell-like form.

The invention can be used for discharging long, straight heaps or round heaps, and in both cases, the conveyor members remove material from the side of the heap. For this purpose, the guide wall referred to in Claims 3 to 6 is very advantageous. The guide walls promote gentle transfer of the material onto the carrying surfaces and uniform filling of the material onto the conveyor members.

There may be a row of two or more straight heaps side-by-side in a storage plant, and it is preferable to remove the material from the facing sides of two adjacent heaps by means of a single apparatus. For this purpose, the apparatus can have guide walls on each side of each carrier member, and the guide walls can be as set forth in Claim 5.

However, if the apparatus is being used for discharging a round heap, it is normal to position the apparatus always with the same side against the side of the heap, and the guide walls need only be provided on one side of each carrier member. It is preferable for the arrangement to be as set forth in Claim 6, i.e. the (cell-like) spaces above the carrying surfaces are oblique to the axis of conveyance.

The carrying surfaces can be spaced a predeter mined distance above the floor of the heap so that they do not slide on the floor and not prematurely worn away. For this purpose, the apparatus can be as set forth in Claim 7, and in this way the traction members are relieved of the weight of the loaded carrier members and the wear is substantially restricted to that on the projections, which are easily exchangeable; furthermore, the projections enable one to maintain a predetermined, though small, spacing between the bottoms of the carrier mem bers and the floor of the heap because they loosen up the material resting on the floor and prevent a layer of this material pushing the carrier members up out of their correct path.

Description of Preferred Embodiments The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a partly schematic side view of part of a plant for the storage of particulate materials, including apparatus of the invention; Figure 2 is a plan view of part of the apparatus, on a larger scale; Figure 3 is a perspective view of a carrier member of the apparatus; and Figure 4 is a plan view, corresponding to that of Figure 2, but showing a different embodiment of the carrier member.

The apparatus of Figure 1 includes a bridge which is of conventional structure and is not shown; the bridge can be moved up against the side of a heap and in general terms extends across the heap, though it will not normally extend across the very top of the heap. If the heap is a straight heap, the bridge will move parallel to the longitudinal axis of the heap, on rails also parallel to the longitudinal axis; if the heap is a round heap, the bridge will swing about a vertical axis approximating to the centre of the heap.

The bridge supports a conveyor whose path is fixed in relation to the bridge. The conveyor has two parallel, spaced traction members in the form of pivoted-link chains 1 which are guided around two star wheels 6 adjacent respective ends of the bridge.

The two chains 1 are substantially identical and each has a straight lower run or section which extends parallel to the axis of the bridge and is the section which discharges the bulk material.

Spaced conveyor members 3 are fixed between the chains 1. Each conveyor member 3 has a support 2 which is fixed by means of a connection piece 21 with each of the two respective links 11 which face each other on either side of the conveyor member 3.

A substantially horizontal carrying surface 31 projects rearwardly from the support adjacent the floor 7 of the heap, i.e. in the direction opposite to the direction of conveyance (indicated with the arrow P) and substantially contacts the following conveyor member 3.

A preferred form of a conveyor member 3 is shown in Figure 3. The conveyor member 3 has a rear wall 32 which forms part of the support 2 and extends down as far as the carrying surface 31, its lower edge being connected with the carrying surface 31. The middle part of the carrying surface 31 is flat, but its lateral zones 34 are inclined downwardly. The middle part of the rear wall 32 is also flat, but its side zones 35 are inclined forwards and have upper, horizontal wings 33 which project rearwards.

The sections 33 are connected to a top part which comprises two flat pieces 22, 23, forming a rigid structure. The connection piece 21 (see Figure 1) is fixed to the upper flat piece 22. The construction is stiffened by two struts 36 which extends between the top flat piece 22 and the rear wall 32.

A guide wall 4 is provided on each side of the conveyor member 3, fixed to the sections 35. The lower edge of each guide wall 4 is adjacent the carrying surface 31 and the guide wall 4 projects forwards and outwards away from the rear wall 32.

The lower edge zones 41 of the guide walls 4 are inclined forwardly with respect to the perpendicular to the axis or direction P of conveyance; this perpendicular is the line in the vertical plane, i.e. the vertical if the axis of conveyance is horizontal. In effect, the lower edge zones 41 are also inclined downwards and towards each other. The whole conveyor member 3 is symmetrical about its longitudinal mid-piane so that it does not matter which side is brought up against the heap.

The lower side of the carrying surface 31 has replaceable projections 37 for sliding along the floor 7 of the heap and keeping the carrying surface 31 away from the floor 7.

Figure 4 shows a discharge conveyor having guide walls 4 on only one side of the conveyor members.

Conveyor members having guide walls on only one side are lighter and cheaper than those with two guide walls, and this is no disadvantage with round heaps which are normally only discharged using one side of the discharge conveyor. If the heap is to be discharged using only one side of the conveyor members, it is preferred that the sides of the spaces above the carrying surfaces do not make a right angle but an acute angle with the axis of conveyance as this can increase the amount of material taken up by each carrying surface. In Figure 4, the conveyor members would be constructed so that their rear walls were swung slightly in an anti-clockwise direction to achieve this effect.

In operation, the lower run of the discharge conveyor moves in the direction P and the star wheel 6 rotates anti-clockwise. The material at the side of the base of the heap is passed by the respective guide walls 4 into the space between adjacent conveyor members 3 and comes to rest on the carrying surfaces 31. These carrying surfaces 31 are close to each other and substantially form a moveable platform on which the material lies and undergoes no rolling movement during its further transport. As can be seen in Figure 1, the conveyor members 3 have a somewhat L-shaped form, and when they reach the star wheel 6, the carrying surfaces 31 are tilted and the material slides off onto a conveyor 5; this does not introduce a great amount of rolling movement and the fall need not be very great, so that the transfer onto the conveyor 5 is relatively gentle. Overall, the invention reduces the rubbing of the particles of the material against each other, wear of the particles by friction and fracture of the particles.

Claims

1. Apparatus for discharging material from a heap, comprising: a moveable bridge for extending across the heap; a discharge conveyor have two endless, parallel traction members extending parallel to the bridge and spaced conveyor members each fixed to each of the two traction members, each conveyor member having a generally horizontal, rearwardly-projecting carrying surface which is adjacent the following conveyor member when the conveyor members are in the section of the conveyor which discharges the material, an opening being left on at least one side so that in operation material can enter the opening and lie on the carrying surface; and means for removing the material from the carrying surfaces.

2. The apparatus of Claim 1, wherein each conveyor member has a transverse wall which extends down as far as the carrying surface.

3. The apparatus of Claim 1 or 2, wherein a guide wall is provided on at least one side of each conveyor member, the lower edge of the guide wall being adjacent the carrying surface and the guide wall projecting forwards and outwards.

4. The apparatus of Claim 3, wherein at least the lower portion of the guide wall is inclined forwardly with respect to the perpendicular to the axis of conveyance.

5. The apparatus of Claim 3 or 4, wherein a said guide wall projects from each side of the conveyor member and both guide walls are symmetrical about the longitudinal mid-plane of the conveyor member.

6. The apparatus of Claim 3 or 4, wherein a said guide wall projects from one side of the conveyor member and the sides of the spaces above carrying surfaces are inclined to the axis of conveyance.

7. The apparatus of any one of the preceding Claims, wherein the lower side of the carrying surface has projections for keeping the carrying surface away from the floor of the heap.

8. The apparatus of any one of the preceding Claims, wherein the traction members are pivoted~ link chains and each carrier member is fixed to a link of each of the two chains.

9. Apparatus for discharging a heap, substanThal- ly as herein described with reference to, and as shown in, the accompanying drawings.

10. Plant for the storage of particulate materials, including a base on which the particulate materials are heaped and apparatus as claimed in any one of the preceding Claims for discharging the heap, the bridge being moveable with respect to the base in a direction generally transverse to the movement of the discharge conveyor.