Conveyors: power-driven – Conveyor section – Bucket
Reexamination Certificate
2001-03-13
2002-10-01
Bidwell, James R. (Department: 3651)
Conveyors: power-driven
Conveyor section
Bucket
C198S712000
Reexamination Certificate
active
06457576
ABSTRACT:
The invention relates to a continuous cable conveyor for steep and substantially vertical up-and-down transport of preferably bulk and fluid materials up to extreme transport heights of approximately 1,000 m. The material to be conveyed can thereby be filled in directly on the outside of the transport line. As a consequence also the delivery of the material to be conveyed takes place on the outside of the transport line in response to the transport speed and the return radii in accordance with the gravity or the centrifugal force principles. The material to be conveyed can, however, also be filled in directly on the inside of the transport line. The delivery of the material to be conveyed then necessarily takes place on the inside of the transport line as well according to the gravity principle.
The fields of application of such conveyors are manifold and of an increasing significance, since the winning of mineral raw materials by miners from open cut minings and drift minings having different deepnesses is increasing worldwide. Also fields relating, for instance, to cavern constructions or the construction of underground traffic routes set high demands in view of steep to vertical transports of bulk materials also from greater deepnesses. On the other hand, an increasing importance is to be seen in the down-transport, if, for example, various waste materials in the form of bulk materials have to be supplied to underground mining cavities or caverns for the ultimate waste disposal thereof.
The continuous transport of bulk material streams as of approximately 50 m
3
/h is already said to be economically superior as of transport heights of approximately 40 m over the non-continuous transport in drift mining, so that the pertinent state of the art is characterized by the existence of various conveying means up to a transport height range of approximately 120 m. Part thereof are the so-called bucket type elevators in manifold embodiments, whereby the dead weight of the endlessly revolving transport line and the stability thereof define a maximum transport height. The maximum transport height of bucket type elevators having a steel cord belt as traction means is approximately 120 m whereby particularly the admissible stability of the endless connection of the steel cord belt limits the transport height.
The system POCKETLIFT® is an embodiment derived from the steel cord belt bucket type elevator, in which the transport line is formed of two endless closed steel cord belts as traction means and between which the carrier means are fixed at distances from each other. The maximum transport height presently obtained with said system is approximately 200 m (see PAELKE, J. W.: “Progress with Continuous Steep Angle and Vertical Conveying”, bulk solids handling, Volume 16, Number 1 January/March 1996).
A further increase of the transport height with said system is only possible if the stability of the belts and the width thereof is increased. Said measures, however, entail an increase in the dead weight of said traction carriers, so that the success is limited and the problem in view of the endless connection of said traction carriers is increased. By taking into account technical and economical criteria, the maximum lifting height during the transport of relevant material streams to be conveyed will have to remain limited to approximately 300 m in connection with the POCKETLIFT® system.
When using cables as traction means for endless closed transport lines increases in the transport height by far surpassing the above can basically be achieved, whereby especially cables made from extremely resistant fibers have particularly high stability values with low dead weights. Moreover, only said cables allow carrier means to be fixed by means of specific cable clamping connections (see German Patent 19702661). German Patent 3142572 moreover describes a device for detachably connecting cable ends, especially of cables with revolving cable drives in cable conveyors, which are at least suited, like the aforementioned cable clamping connections, for returns in the same direction inside a cable conveyor having an endless closed transport line.
Such a cable conveyor is described in the Glückauf-Forschungsheft (Glückauf Research Magazine) 52 (1991), No. 3, pages 95-98 as well as in Hebezeuge und Fördermittel (Lifting Tools and Conveying Means), Berlin 37 (1997) 12, pages 533-536.
Both publications describe the knowledge that solely cables made from extremely resistant fibers, especially from aramides, are suited as traction means in such cable conveyors. The pertinent cable clamping connections and the detachable endless connections are thereby so designed that cable pulleys for the drive, the return and diverse deflections can be passed without any difficulties, i.e. without disadvantageous polygon effects.
A cable bucket type conveyor is described in U.S. Pat. No. 4,227,609, where the cables are inserted as laterally disposed traction means. The carrier means are clamped between said cables at the bends thereof at distances from each other. The returns of the transport line are possible only in one bending direction.
The German laid open application 3641964 likewise describes a conveyor for the continuous vertical transport of bulk materials at great transport height differences comprising cables made of extremely resistant fibers as traction means, which allows returns of the transport line in one bending direction only.
In view of the detachable endless connection of the traction means the number thereof is, moreover, limited to a few cables per side only, which opposes a maximization of the transport height.
The German Patent 638986 describe s an endless conveyor comprising catches such as plates, containers or the like attached to the driving members formed of cables, which, in view of a maximization of the transport height and the stability values in the traction means entailed thereby, is not suited for the aimed at transport height range up to approximately 1,000 m.
The transmission of the peripheral forces to the drive pulley, which is partially non-positive and partially positive, can technically not be realized even with small transport heights and transport speeds.
Said assessment also refers to the variant of a conveyor described in U.S. Pat. No. 3,338,379.
The European Patent Application 0020148 describes improvements relating to bucket type elevators and conveyors allowing a bending direction of a transport line with laterally disposed cables as traction means in alternate directions. In this case, however, the returns are possible only with cable pulleys having corresponding recesses for the attachment points of the carrier means and the endless connection. Here, too, the provided positive transmission of the peripheral force only allows the use in secondary cases of application, in other words, for small transport heights and thus small stability values in the traction means, the number of which has to remain limited to a great extent for constructional reasons.
The German laid open application 19623143 describes a conveyor for the continuous inclined and vertical transport of bulk materials and sludges up to extreme transport heights involving a reception of the material to be conveyed primarily in accordance with the bailing principle, with the traction means being formed of extremely resistant fiber cables and the carrier means being fixed thereon by means of clamping connections at distances from each other such that returns of the transport line are possible in one bending direction only.
A transport line constructed in such a fashion, which is provided with at least one detachable endless connection, basically allows the realization of transport heights in the aimed at range. However, the expectations have to be reduced in view of the likewise desired high transport streams. The proper charging according to the bailing principle only allows low transport speeds and limits the number of materials capable of being transported. Increased bailing resistances, moreover, constitute an a
Günther Roland
Paelke Jürgen W.
Bidwell James R.
Svedala Industri (Deutschland) GmbH
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