Mining or in situ disintegration of hard material – Cutter tooth or tooth head – Tooth mounted on helical head portion or head with helical...
Patent
1993-08-23
1995-01-03
Bagnell, David J.
Mining or in situ disintegration of hard material
Cutter tooth or tooth head
Tooth mounted on helical head portion or head with helical...
37 91, 37 96, 37190, 299 39, E21C 2516, E21C 4700
Patent
active
053780493
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to the use of a disc-shaped rotary cutter for excavating hard mineral rock layers.
2. Description of the Related Art
DE-OS [German Unexamined Published Patent Application] 3,822,200 discloses a method of excavating limestone (marl) in which the limestone is produced directly in small sized grains in one process phase during the excavation in essentially a grain size that can be transported on a conveyor belt. The preferred excavator employed is a bucket wheel excavator. Although bucket wheel excavators are now available that can be used in harder rock layers, their performance is limited if they are of conventional configuration, particularly when considering the wear that occurs at the cutting elements. Beginning with a certain rock hardness, conventional methods must be employed, such as drilling, blasting, excavation by a mechanical shovel, loading onto trucks or transporting by rail, breaking up the essential limestone component as well as transporting it further on conveyor belt systems. The multitude of process steps performed from excavation to conveyor belt transport results not only in great delays but also in a relatively small throughput with high costs for materials and personnel. Due to the blasting, the material remains in large pieces and must be almost all fed into a crusher before it can be transported further.
East German Patent 10,487 discloses an excavator for digging small trenches by cutting blades that are disposed at blade supports of a pivotal wheel disc and guide rings that are provided on both sides of the cutting blades. The blade holders and the cutting blades are alternatingly fastened to one side of the blade supports. This type of excavator, which is also known as a trench cutting machine, is provided exclusively to produce trenches of a relatively small width and depth (depending on the diameter), with generally no hard rock layers being involved, but rather loose soil or clay, so that no high demands are made with respect to wear of the cutting elements.
SUMMARY OF THE INVENTION
It is the object of the invention to conceive a continuous process that operates economically and with which hard rock can be excavated without blasting while substantially avoiding a crushing process.
This is accomplished by the use of a disc-shaped rotary cutter for hard mineral rock layers. The cutter has a cylinder compressive strength of equal to or greater than 20 MPa, with the cutter being provided with a plurality of cutting elements at its circumference and also at its end faces. Disc-shaped cutters are generally employed for chip removing work on materials, particularly metals, with these disc-shaped cutters being employed exclusively for cutting grooves or faces. Broader applications have not been disclosed to date.
By using the advantageous cutting technology known for disc-shaped cutters as employed for metals for the cutting wheels of, in particular, bucket wheel excavators, it is now possible to also employ them for harder rocks requiring cylinder compressive strengths of equal to or greater than 20 MPa with acceptable wear of the cutting tools. The expensive, otherwise conventional work of blasting can consequently be substantially avoided.
Advantageous modifications of the subject matter of the invention are disclosed in the following specification and claims.
Examples for hard rock that can be excavated are limestone, clay stone, sandstone and hard coal. The large number of cutting elements on the circumference of the rotary cutter with an appropriate arrangement of the teeth in conjunction with the relatively high installed driving power produce, on the one hand, a very quiet run and, on the other hand, a corresponding fineness of the excavated rock, thus essentially eliminating the necessity of subsequently connected crushing systems.
BRIEF DESCRIPTION OF THE DRAWINGS
One embodiment of the invention is illustrated in the drawing figures and will be described as follows. In the drawing figures;
FIG
REFERENCES:
patent: 3680919 (1972-08-01), Rear et al.
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patent: 3967854 (1976-07-01), Posciri
patent: 4755004 (1988-07-01), Palmquist et al.
patent: 4979781 (1990-12-01), Bothwell et al.
41/0618 d1 038910 from Krupp Industrietechnik [Industrial Technology] GmbH, (undated).
Gluckauf [Good Luck ] 117 (1981), No. 15, p. 926.
R. Sager et al., Weinterentwicklung der kontinuierlichen Tagebautechnologie fur festere Materialien.sup.2, Mar. 1990.
Fleischhaker Wolfgang
Mett Joachim
Bagnell David J.
Krupp Fordertechnik GmbH
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