GB2172878A - A spiral chute assembly for blind shafts in underground mining works, preferably for intermediate bunkers - Google Patents

Abstract

A spiral chute assembly for blind shafts 1 in underground mining works, preferably for intermediate bunkers, comprises a spiral chute fixed to the inner wall of a casing, or formed in the wall of the shaft and defining an inner space, which can itself be used as an intermediate bunker, within the eye of the spiral. An access and air tunnel 10, which has parallel vertical side walls, is formed under the spiral chute using the chute as a roof and inspection apertures are provided in one of the two side walls or the floor of the tunnel. The area surrounding the casing 12 can be used for storing material, which reaches this area via holes in the casing (Figure 2, not shown), and a further spiral chute may be employed in this outer area (Figure 3, not shown). <IMAGE>

Description

SPECIFICATION A spiral chute assembly for blind shafts in underground mining works, preferably for intermediate bunkers The invention relates to a spiral chute assembly for blind shafts in underground mining works, preferably for intermediate bunkers, consisting of a spiral forming an inner spiral space, which can itself be used as an intermediate bunker within the eye, wherein the conveyed material reaches further bunkering space via the chute throat of the spiral passages and their top edges into an annular chamber in the blind shaft.

In particular, in the output of raw coal in pit coal mining, blind shafts serve for the comparison measurement of the continuous material conveyance, usually between two series connected belts.

The bunker in this way takes up the delivery of the first connected continuous conveyor which would exceed the delivery capacity of the subsequent continuous conveyer and transfers these conveyed quantities to the subsequent continuous conveyor if the first connected continuous conveyor carries a smaller quantity. If both quantities are equal, the spiral chute serves for the bypassing of the bunker chamber. If the delivery of the first connected continuous conveyor exceeds that of the subsequent continuous conveyor the excess delivery overflows into the bunker space over the edge of the spiral chute.

Such intermediate bunkers are described as main end bunkers, which are constantly connected in the conveying route. Distinguishable from these are shunt bunkers which can normally be bypassed by the series connected continuous conveyors and can be connected in the conveying route, e.g. via a quantity divider such as a shunt conveyor arranged on the passage of the first connected continuous conveyor as soon as the quantity exceeds the capacity of the subsequent continuous conveyor; frequently such shunt bunkers are emptied by a vibrating trough onto the subsequent continuous conveyor which is controlled by a conveyor type weigher. The invention can be used on main end and shunt bunkers of the type described.

The assembly of a spiral chute in such main and shunt bunkers avoids the dust problem prevalent in so-called free fall bunkers or fall bunkers and the grain disintegration of the conveyed material, which frequently results in a reduction in production. The suppression of dust saves water, which is used to lay the dust; however it frequently negatively affects the chute capacity of the conveyed material in the intermediate bunker. In general, the type of spiral chute with which the invention is concerned comprises a base sheet metal spiral, which can have a chute surface coating. This can consist of highly wear-resistant, tempered, alloyed cast steel sheets, these sheets being also frequently provided with a wear-resistant, two-component resin in order to lower their surface roughness when the bunker is in operation.Under wet conditions an enamelling of the spiral shots and the base sheet metal is advisable to give corrosion protection.

The inner spiral chute itself forms an intermediate bunker which is bounded inwardly by the socalled eye of the spiral, i.e. the free space surrounding the centre axis of the spiral, and outwardly by the spiral shots or a pipe casing. Such a pipe casing stands in a blind shaft or a large bore aperture and can be surrounded by an annular chamber which usually remains free. If however there is a blind shaft of large diameter, the annular chamber of the blind shaft outside the spiral chute will generally be used as bunker space as soon as the intermediate bunker overflows. Where there are outer spiral chutes, the spiral passages are either fixed on the joint of the blind shaft or positioned in the joint. The first mentioned type of assembly is suitable preferably for cases in which free fall bunkers have to be changed over to spiral bunkers.

In general it is important with intermediate bunkers to avoid disturbance in conveyance which mainly arises through blocking in the conveyed material. Moreover the bunkder must itself guarantee a negotiable air passage in order to avoid as far as possible the need for special air conditioning at the outlet and inlet of the bunker.

The invention stems from a known spiral chute assembly (DE-OS 30 16 789). In this case an inner cylinder is assembled in the blind shaft from sheet steel which inwardly locks the loading chamber of the bunker bounded outwardly by the bunker wall.

The inside of the inner cylinder serves as transport space which is provided with a spiral staircase, and also as a through air passage between the bunker entrance and exit; moreover the spiral passages are preferably fixed to the outer wall of the inner cylinder. On the one hand an optimum size is arrived at for the loading chamber of the intermediate bunker by the arrangement of the inner cylinder. On the other hand the inner cylinder makes possible a negotiable air passage through the bunker which cannot be blocked by conveyed material.

The known spiral chute assembly presupposes an annular bunker which does not extend below the determined minimum measurements of its restricted inner chamber. This results from the inner cylinder which must be accommodated in the shaft cross-section of the blind shaft. Spiral chute components, as provided inter alia in vertical large bore apertures, are therefore usually not traversable and cannot be used as established air passages. Up to now cylindrical bunkers with outer spirals and a large diameter are equally unsuitable for known spiral chute assemblies because the conveyed material creates suction forces on the inner cylinder on its departure from such a bunker, such forces becoming so strong that the assembly is damaged or completely destroyed.

The invention has for its object the means for solving the problem of creating a spiral chute assembly which is independent of the size of the blind shaft, i.e. of its restricted diameter, creates a spiral chute serving to bypass the bunker space and a negotiable air passage from which the spiral chute and the bunker chamber can be inspected and maintained from a number of places through the height of the bunker.

In accordance with the invention there is provided a spiral chute assembly for blind shafts in underground mining works, generally for intermediate bunkers, comprising a spiral forming an inner spiral space, which can itself be used as an intermediate bunker within the eye, wherein the conveyed material reaches further bunkering space via the chute throat of the spiral passages and their top edges into an annular chamber in the blind shaft, the spiral passages forming the cover of a transport and air tunnel, which has parallel and vertical walls which are arranged at the inner edge of the spiral or its outer edge attached to the eye of the spiral and the tunnel having a negotiable floor which connects the walls above a downwardly connecting spiral passage, wherein apertures are provided in one of the two side walls or the floor being closeable by inspection covers.

The transport and air tunnel provided under the spiral passages is so arranged that it uses up the space under the spiral, whose inclination under current conditions has an amplitude of ca. 2.2.m for coarse pit-coal conveyance. In this way the intermediate bunker capacity of the spiral chute is not substantially restricted; simultaneously however the stability of the spiral is considerably increased with the rigidity of the transport and air tunnel, surrounded by its walls, ceiling and floor.

As it is possible nevertheless to instail any desired number of apertures through which inspection and maintenance can take place, the spiral chute and the bunker chamber can be evaluated at correspondingly many and correctly divided spaces from the safe standpoint of the transport tunnel and measures taken to clear blockages.

In intermediate bunkering it has arisen that the bunkered conveyed material includes air and that these air pockets are compressed on removal of the conveyed material. On draining of the bunker a sudden release of the compressed air occurs.

Whilst up to now the air in the bunker generally escapes downwardly out of the bunker drain and thereby throws unwanted dust clouds onto the conveying track, with this invention the air finds its way into the transport and air tunnel and thereby less dust is caused, which, moreover, wili be carried off upwardly by means of the usual descending airduct.

The invention makes possibie, in known vertical type spiral conveyors whose eye forms the intermediate bunker, a suitable transport and airing facility which up to now was completely lacking and is now provided by the integrated transport and air tunnel. In larger intermediate bunkers, which have a loading chamber outside the spiral and the intermediate bunker space formed by it in the annular chamber between the spiral chute and the joint of the blind shaft which is loaded, on overflow of the conveyed material from the spiral chute, the loading chamber by reverse flow of the delivery material, is emptied into the spiral chute on decreasing bunker loading, the arrangement of the invention makes possible a transport and air tunnel which remains aired and traversable during any of these operations.

Preferably the transport and air tunnel has roof girders which support a base sheet metal spiral of the spiral.

With these it is possible to operate the upper end of the transport and air tunnel by a roof plate whereby the girders support the base sheet metal spiral of the spiral which in other embodiments of the invention simultaneously forms the roof plate of the transport and air tunnel.

Conveniently, the floor of the transport and air tunnel is provided with steps which have vertical wall plates with hinge joints on their front edge, to which horizontal step plates are hinged, which are supported on the lower edge of the following horizontal step plate. This enables a more convenient transport possibility and a practical arrangement of apertures through which one may view the intermediate bunkering, whereby the apertures are also suitable for elimination of conveyance disturbances.

Preferably also the inner wall of the transport and air tunnel is formed from a sheet metal spiral running parallel to the outer wall, and the lines of dip of the spiral passages and the floor of the transport and air tunnel run parallel. Only the respective upper part of the chamber under the vertical projection of the spiral passages is taken up with the transport and air tunnel. Due to the steepness of the spiral passages there is sufficient intermediate bunker space on the spiral passages to the floor of the transport and air tunnel opposite.

Advantageously, the outer wall of the transport and air tunnel is part of a through pipe casing which has a large number of apertures divided along its length, which are arranged over the chute surface of the spiral and serve for the conveyance of the conveyed material into an annular chamber of the intermediate bunker. This considerably strengthens the spiral chute assembly and is therefore already suitable for intermediate bunkering which, due to its size and its vertical length, exerts a considerable suction effect on the spiral chute assembly on removal of the bunkered material. In this way the apertures serve as overflows which makes possible the transfer of the conveyed material from the intermediate bunker of the spiral chute into the annular chamber of the bunker or blind shaft at several places through the depth of the blind shaft.

The pipe casing of the spiral chute assembly may be closed and serve for the storage of an outer spiral chute whose inner edge partly bears on the outer cover whereby the inlet of the inner spiral has an overflow through an opening which leads into the outer spiral. This provides a more precise control of the conveyed material is achieved according to the load of the intermediate bunker than is possible with the previously mentioned embodiment. The inner spiral thus copes with the normai conveyance from which the annular chamber of the bunker remains undisturbed. As soon as the conveyance through the inner spiral ceases and the intermediate bunkering capacity of the inner spiral is used up, the annular chamber of the bunker is filled over the outer spiral, which happens sparingly until the inner spiral is free again.The removal of the conveyed material bunkered in the annular chamber results on draining of the bunker and therefore leaves undisturbed the conveyance through the inner spiral.

In accordance with a further aspect, the invention relates to a spiral chute assembly for blind shafts in underground mining works, which serve as intermediate bunkers, consisting of a spiral forming an outer spiral, which has an overflow over its inner edge aligned with the wall of the bunker or inwardly projecting over this, the spiral passages forming the cover of a transport and air tunnel, which parallel and vertical walls which are arranged on the inner edge of the spiral and on its outer edge and a negotiable floor which connects the walls above a downwardly connecting spiral passage, whereby the floor or the inner wall of the transport and air tunnel is provided with apertures which are closeable by inspection covers.

The invention also refers to outer spirals which are usually provided in round bunkers of considerable diameter whereby the outer spiral in the bunker wall is removed from the damaging effect of the bunkered material on emptying of the bunker. These bunkers up to now do not possess a negotiable air passage from which the spiral chute and the bunker space can be inspected and maintained at a number of places divided over the depth of the bunker.

The details, further features and other advantages of the invention are given in the following description of embodiments of the invention with reference to the figures in the drawing, which show: Figure 1 - a vertical cross-section of a spiral chute assembly constructed in accordance with the invention in which the intermediate bunkering capacity is only shown in the inner chamber of the spiral, Figure 2 - a similar construction to that in Figure 1 but with a round bunker of a first embodiment, Figure 3 - a similar construction to Figure 2 but showing an altered embodiment of the invention, Figure 4 - a construction similar to Figures 2 and 3, having a blind shaft with outer spiral, Figure 5 - a detail of the spiral chute assembly according to Figure 2, and Figure 6- a section along the line VI-VI of Figure 5.

According to the embodiment of Figure 1, lagging 1 defines a wide bore aperture 2 which leads from an upper level 3 to a lower level 4. A steel cylinder 5 is displaced in the wide bore aperture 2, being offset on the level 4. A number of carriers 6 serve for displacement of the cylinder of sheet steel or pipes. The carriers are not shown in detail but span the annular chamber 7 which is provided between the lagging 1 and the outer surface 8 of the sheet steel cylinder 5.

The sheet steel cylinder serves as the outer casing of a single layer spiral 9. In contrast to the cast sheet steel lagged chute surfaces of a base sheet metal spiral a simple arrangement is thus provided. The spiral 9 forms the cover of a transport and air tunnel 10 which has parallel walls 11, 12. In the example shown the outer wall 12 is formed from the outer casing 5. The inner wall 11 consists of a vertical inner sheet metal spiral which is generally identified at 13. The chute throat 14 of the spiral 9 terminates at the outer edge 15 which extends to the inner side of the outer casing 5 and inwardly to the inner edge 16 of the spiral 9 to which the inner spiral 13 is fixed. Moreover the transport and air tunnel 10 has a negotiable floor 17 which connects the two walls 11, 12 together.In the spiral 13 forming the inner wall 11 of the transport and air tunnel 10 there are apertures through which one can view the eye of the spiral chute, that is the free space which is formed around the centre axis 18 of the pipe 5 inside the spiral passages. These apertures are closable with inspection covers (not shown).

In use the spiral chute assembly generally indicated at 20 is positioned above the discharge end 21 of an upper continuous conveyor 22 which in the embodiment shown is a conveyor belt. So long as the quantity being conveyed by the spiral 9 corresponds to the capacity of a second continuous conveyor 23, constructed on the lower level 4 as a conveyor belt, which is connected behind the continuous conveyor 22 and is supplied over a saddle roof type inclined outlet floor 24 from a hopper 25, the conveyed material on the spiral 9 flows downwardly. If the quantity being conveyed by the upper continuous conveyor 22 exceeds the capacity of the lower continuous conveyor 23, it overflows the inner edge 14 of the spiral and fills up the eye of the spiral chute from the bottom to the top.As soon as the delivery from above subsides, the conveyed material is removed over the inclined floor 24 out of the eye of the spiral chute of the intermediate bunkering capacity provided therebetween by the subsequent continuous conveyor 23 and eventually flows away over the spiral passages 9.

In the embodiment of Figure 1 the transport and air tunnel is elongated downwardly along almost all of the spiral passage 26, so that it can be reached from the level 4 through an inlet 27. On the upper level the transport and air tunnel 20 is extended so far that it can be reached via an inlet 28 from the plane of the level 3.

The embodiment example of Figure 2 differs from that of Figure 1 essentially by the considerably larger diameter of the blind shaft 2, which is aligned at the location of the large bore aperture according to Figure 1. As a result there is a considerably broader annular chamber 7 which serves as an intermediate bunker and is provided with a funnel-shaped outlet 29 by means of a saddle roof type division of the outgoing material on two apertures. An inclined floor 31 projects into the funnelshaped outlet 29 over which the bunker load outside the projection of the funnel 29 can be removed. The spiral chute assembly 20 however again has the cylindrical sheet steel casing 5 which rests on the lower level 3 and is held at the upper level 4 by the carriers 6.On the lower level 3 the inclined floor 31 is supported by supports 32, girders 33 and auxiliary supports 34 supporting the funnel 29.

In contrast to the embodiment of Figure 1 the sheet steel cylinder 5 has open apertures 34, a large number of which are distributed over the vertical length of the sheet steel cylinder 5 and which are located in each case above the respective spiral passage portions. As a result conveyed material can overflow through these apertures 34 as soon as the intermediate bunkering of the spiral 9 is exhausted.

According to the representation in Figure 5 the floor 18 of the transport and air tunnel 10 is formed from a number of steps which are shown as 35 to 37 in Figure 6. The outer wall 12 as well as the inner wall 11 of the transport and air tunnel 10 have a number of inspection covers 38, 39 divided through its height. These covers lie below a roof girder 40 which supports the base sheet metal 41 of the spiral. The chute surface lagging necessary in this embodiment is not shown. The arrow A shows the view direction from above, into the spiral chute.

Further apertures 40, 41 are provided in the steps of the stairway 35 to 37. They are located below the horizontal step plates 42 to 44 and are closed by covers 46 to 47 which form the vertical step plates. These covers self-close under pressure of the outer conveyed material. They can be pushed open from inside, thereby enabling a free view of the bunkered material. The covers hang on hinges 48,49 which are arranged under the horizontal steps of the stairway 42 to 44 and are supported on the back edge of each following horizontal step plate 35 to 37. In contrast to the embodiment of Figure 1 the annular chamber 7 of the bunker is filled as soon as the intermediate bunkering capacity in the eye of the spiral is exhausted. For this purpose the material overflows through the aperatures 34 in the annular chamber 7.Provided however the quantity being conveyed by the first connected continuous conveyer 22 corresponds to that of the subsequent continuous conveyor 23, the delivery material eventually finds its way through the spiral 9 into the outlet funnel 29.

In contrast to the embodiment of Figure 2 no apertures 34 are provided in the sheet steel cylinder 5 of the spiral chute assembly 20 of the embodiment of Figure 3. Instead an outer spiral chute 51 is provided on the outside 50 of the sheet steel cylinder 5. This is however only on parts of its length, according to the shown embodiment, fixed respectively by a quarter spiral 52 to the cylinder 5. The areas between, e.g. area 53, are free.

In the embodiment of Figure 3, if the capacity of the first connected continuous conveyor 22 exceeds the capacity of the lower continuous conveyor 23, the eye of the spiral chute is filled from bottom to top until the material reaches an aperture 54 through which it can pass from the entrance 55 into the outer spiral 53. The material then passes downwards over the outer spiral 53 and fills the annular chamber 7 commencing from the inclined floor 31 from bottom to top. The delivery material takes up an inclined sloping surface and thereby overflows the outer edge 56 of the outer spiral 53 or the inner edge 57 of this spiral according to the free space available.

The embodiment according to Figure 4 shows an outer spiral 58 which is displaced behind the joint 59 of a blind shaft 60. An escape 61 is located below the spiral which is lagged in the inner chamber 62 of the blind shaft 60 with a vertical spiral wall 63. The outer wall 64 is formed from the junction with the ground. Also the ground forms the floor 65 of the escape 61 which is provided with a number of steps 66 and is negotiable via these. The escape 61 after its completion forms a transport and air tunnel 10. The intermediate bunkering ensues in this case in the small inner chamber 62 of the blind shaft 60 above the inclined floor 67. In the inner wall of the transport and air tunnel 10 apertures 67 are provided with inspection covers (not shown).

Claims (11)

1. A spiral chute assembly for blind shafts in underground mining works, generally for intermediate bunkers, comprising a spiral forming an inner spiral space, which can itself be used as an intermediate bunker within the eye, wherein the conveyed material reaches further bunkering space via the chute throat of the spiral passages and their top edges into an annular chamber in the blind shaft, the spiral passages forming the cover of a transport and air tunnel, which has parallel and vertical walls which are arranged at the inner edge of the spiral or its outer edge attached to the eye of the spiral and the tunnel having a negotiable floor which connects the walls above a downwardly connecting spiral passage, wherein aperatures are provided in one of the two side walls or the floor being closeable by inspection covers.

2. A spiral chute assembly according to claim 1, wherein the transport and air tunnel has roof girders which support a base sheet metal spiral of the spiral.

3. A spiral chute assembly according to either of claims 1 and 2, wherein the floor of the transport and air tunnel is provided with steps which have vertical wall plates with hinge joints on their front edge, to which horizontal step plates are hinged, which are supported on the lower edge of the following horizontal step plate.

4. A spiral chute assembly according to any of claims 1 to 3, wherein the inner wall of the transport and air tunnel is formed from a sheet metal spiral running parallel to the outer wall, and the lines of dip of the spiral passages and the floor of the transport and air tunnel run parallel.

5. A spiral chute assembly according to any of claims 1 to 4 wherein the outer wall of the transport and air tunnel is part of a through pipe casing which has a large number of apertures disposed along its length, which are arranged over the chute surface of the spiral and serve for the conveyance of the conveyed material into an annular chamber of the intermediate bunker.

6. A spiral chute assembly according to claim 5 wherein the pipe casing of the spiral chute assembly is closed and serves for the storage of an outer spiral chute whose inner edge partly bears on the outer cover whereby the inlet of the inner spiral has an overflow through an opening which leads into the outer spiral.

7. A spiral chute assembly for blind shafts in underground mining works, which serve as intermediate bunkers, consisting of a spiral forming an outer spiral, which has an overflow over its inner edge aligned with the wall of the bunker or inwardly projecting over this, the spiral passages forming the cover of a transport and air tunnel, with parallel and vertical walls which are arranged on the inner edge of the spiral and on its outer edge and a negotiable floor which connects the walls above a downwardly connecting spiral passage, whereby the floor or the inner wall of the transport and air tunnel is provided with apertures which closeable by inspection covers.

8. A spiral chute assembly for blind shafts substantially as herein before described with reference to and as shown in Figure 1 of the accompanying drawings.

9. A spiral chute assembly for blind shafts substantially as herein before described with reference to and as shown in Figures 2, 5 and 6 of the accompanying drawings.

10. A spiral chute assembly for blind shafts substantially as hereinbefore described with reference to and as shown in Figure 3 of the accompanying drawings.

11. A spiral chute assembly for blind shafts substantially as hereinbefore described with reference to and as shown in Figure 4 of the accompanying drawings.