1. A deep coal fluidization pipeline conveying system comprises fluidization mining equipment (1), a cage (5), a winch room (10), a head sheave (11) and a ground coal slurry storage station (13); the winch house (10) is arranged on the ground (9), the head sheave (11) is arranged on the vertical shaft (8), the cage (5) is positioned in the vertical shaft (8), a winch rope at the top of the cage (5) is connected into the winch house (10) through the head sheave (11), and the ground coal slurry storage station (13) is arranged on the ground (9) beside the vertical shaft (8);

the device is characterized by also comprising an underground transfer station (4), a fluidized pipeline conveying device (6) and a clean water conveying device (7);

the underground transfer station (4) is arranged in the surrounding rock (3) at the bottom of the vertical shaft (8), the fluidization pipeline conveying device (6) is arranged in the vertical shaft (8), the bottom end of the fluidization pipeline conveying device (6) is communicated with the underground transfer station (4), and the top end of the fluidization pipeline conveying device (6) is communicated with the ground coal slurry storage station (13);

the clean water conveying device (7) comprises a ground water supply station (702) and a clean water conveying pipeline (701), the ground water supply station (702) is arranged on the ground (9) beside the vertical shaft (8), and the clean water conveying pipeline (701) is positioned in the vertical shaft (8) and is communicated with the underground transfer station (4) and the ground water supply station (702);

the fluidized mining device (1) is positioned in the coal seam (2), the fluidized mining device (1) comprises a tunneling crushing cabin (102), a coal slurry preparation cabin (103) and a coal slurry storage cabin (104), and the underground transfer station (4) is communicated with a catalyst supply pipeline (10332) and a clear water supply pipeline (10342) in the coal slurry storage cabin (104).

2. The deep coal fluidization piping system according to claim 1, characterized in that: the edge of the rear side face of the tunneling crushing cabin (102) is connected with the edge of the front side face of the coal slurry preparation cabin (103) through a front hydraulic cylinder (12-1), and the edge of the rear side face of the coal slurry preparation cabin (103) is connected with the edge of the front side face of the coal slurry storage cabin (104) through a rear hydraulic cylinder (12-2); the top surface and the bottom surface between the tunneling crushing cabin (102) and the coal slurry preparation cabin (103) are respectively provided with a flexible expansion plate (1026), and the top surface and the bottom surface between the coal slurry preparation cabin (103) and the coal slurry storage cabin (104) are respectively provided with a flexible expansion plate (1026).

3. The deep coal fluidization piping system according to claim 1, characterized in that: the front end face of the tunneling crushing cabin (102) is provided with a cutter disc group (101), the front side face of the cutter disc group (101) is provided with a main cutter disc (1011) and an auxiliary cutter disc (1012), and the rear side face of the cutter disc group (101) is provided with a main cutter disc driving device (1013) and an auxiliary cutter disc driving device (1014).

4. The deep coal fluidization piping system according to claim 3, characterized in that: a spiral conveyor (1021), a coal crushing chamber (1022) and a crushing chamber hydraulic station (1023) are arranged in the tunneling crushing chamber (102), and the spiral conveyor (1021) is positioned in front of the coal crushing chamber (1022) and is communicated with the coal crushing chamber (1022); the crushing cabin hydraulic station (1023) is respectively connected with the main cutter head driving device (1013) and the auxiliary cutter head driving device (1014).

5. The deep coal fluidization piping system according to claim 4, characterized in that: a grinding chamber (1031), a coal slurry mixing chamber (1032), a catalyst storage chamber (1033), a water storage tank (1034) and a coal slurry preparation chamber hydraulic station (1035) are arranged in the coal slurry preparation chamber (103), the front end of the grinding chamber (1031) is connected with the coal crushing chamber (1022) through a coal conveying pipeline (1025), the rear end of the grinding chamber (1031) is connected with the coal slurry mixing chamber (1032), and the coal slurry mixing chamber (1032) is respectively connected with the catalyst storage chamber (1033) and the water storage tank (1034) through a catalyst input pipeline (10331) and a clean water input pipeline (10341); the coal slurry preparation cabin hydraulic station (1035) is connected with the front hydraulic cylinder (12-1); the catalyst storage chamber (1033) and the water storage tank (1034) respectively extend to the rear part of the coal slurry storage chamber (1041) through a catalyst supply pipeline (10332) and a clear water supply pipeline (10342).

6. The deep coal fluidization piping system according to claim 5, characterized in that: the coal slurry storage chamber (1041), the coal slurry pump (1042) and the coal slurry storage chamber hydraulic station (1043) are arranged inside the coal slurry storage chamber (104), the coal slurry storage chamber (1041) is connected with the coal slurry mixing chamber (1032) through a coal slurry conveying pipeline (10321), and the coal slurry pump (1042) is arranged at the rear end of the coal slurry storage chamber (1041); the coal slurry storage cabin hydraulic station (1043) is connected with the rear hydraulic cylinder (12-2).

7. The deep coal fluidization piping system according to claim 1, characterized in that: the fluidization pipeline conveying device (6) is of a longitudinal multi-section structure.

8. The deep coal fluidization piping system according to claim 7, characterized in that: each section of the fluidization pipeline conveying device (6) comprises a coal slurry lifting pump (601), a spinner (602), a coal slurry lifting pipeline (603) and a coal slurry transferring cabin (604), the coal slurry transferring cabin (604) is arranged in a surrounding rock (3) beside a vertical shaft (8), the upper coal slurry transferring cabin (604) and the lower coal slurry transferring cabin (604) which are adjacent are communicated through the coal slurry lifting pipeline (603), and the coal slurry lifting pump (601) and the spinner (602) are arranged on the coal slurry lifting pipeline (603).

Background

Currently, underground mining is the main mining mode for underground coal resource mining. The method comprises the steps of firstly completing underground coal mining on a coal mining working face by means of cooperative work of three fully mechanized coal mining machines (a coal mining machine, a hydraulic support and a scraper conveyor), then transporting the coal to the lower part of a mine through transportation equipment such as a belt conveyor and a rail mine car, and finally lifting the coal to the ground through a mine hoist. Along with the increase of the mining depth, the stress level of a coal rock body is increased, the phenomena of high ground stress, high ground temperature and high karst water pressure appear, surrounding rock flow makes a roadway difficult to support, the construction and maintenance cost of the roadway is increased rapidly, and the phenomena of coal wall caving, roof leakage and the like easily occur on a coal mining working face, so that the underground mining is obviously limited by the mining depth and is not suitable for the mining of deep resources. Analysis has shown that the ultimate depth of the well under the prior art conditions is about 1500 m. However, nearly 70% of solid resources in China are distributed in the depth of 2000m, so that the existing coal mining mode and mining limit depth are broken through, and the resource potential towards the deep part becomes inevitable selection and great practical requirement.

In 2016, researchers innovate and provide subversive theory and technical idea of deep coal resource fluidization exploitation, the core idea is to convert deep solid mineral resources into gas state, liquid state or gas-solid mixed state in situ, and realize unmanned intelligent mining, selection, charging and electric heat conversion underground. On the basis, patent CN202010156902.X provides a fluidization return mining structure and method suitable for deep coal resources, and points out that only one horizontal main roadway and one fluidization resource underground transfer station are required to be arranged when deep coal resources are mined, and the supply and output of fluidization mining equipment during underground mining pass through the transfer station, but the patent does not make clear the specific structural composition of the fluidization mining equipment and how to convey the coal resources to the ground. Therefore, it is necessary to design a mining system and a coal slurry fluidization vertical conveying system which integrate a tunneling crushing cabin, a middle conversion cabin, a capacity output cabin and a filling cabin, can independently walk and can convert in-situ coal slurry of coal.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a deep coal fluidization pipeline conveying system, and underground fluidization mining equipment can realize mining, screening and in-situ conversion of deep coal into coal slurry; the transportation part is a pipeline vertical lifting device and adopts a multi-section lifting mode to convey coal slurry to the ground.

In order to achieve the purpose, the invention provides the following technical scheme: a deep coal fluidization pipeline conveying system comprises fluidization mining equipment, a cage, a winch room, a head sheave and a ground coal slurry storage station; the winch room is arranged on the ground, the head sheave is arranged on the vertical shaft, the cage is positioned in the vertical shaft, the twisted rope at the top of the cage is connected into the winch room through the head sheave, and the ground coal slurry storage station is arranged on the ground beside the vertical shaft; the device also comprises an underground transfer station, a fluidized pipeline conveying device and a clean water conveying device; the underground transfer station is arranged in surrounding rock at the bottom of the vertical shaft, the fluidized pipeline conveying device is arranged in the vertical shaft, the bottom end of the fluidized pipeline conveying device is communicated with the underground transfer station, and the top end of the fluidized pipeline conveying device is communicated with the ground coal slurry storage station; the clear water conveying device comprises a ground water supply station and a clear water conveying pipeline, the ground water supply station is arranged on the ground beside the vertical shaft, and the clear water conveying pipeline is positioned in the vertical shaft and is communicated with the underground transfer station and the ground water supply station; the fluidized mining equipment is positioned in a coal seam, the fluidized mining equipment comprises a tunneling crushing cabin, a coal slurry preparation cabin and a coal slurry storage cabin, and the underground transfer station is communicated with a catalyst supply pipeline and a clear water supply pipeline in the coal slurry storage cabin.

Furthermore, the edge of the rear side surface of the tunneling crushing cabin is connected with the edge of the front side surface of the coal slurry preparation cabin through a front hydraulic cylinder, and the edge of the rear side surface of the coal slurry preparation cabin is connected with the edge of the front side surface of the coal slurry storage cabin through a rear hydraulic cylinder; the top surface and the bottom surface between the tunneling crushing cabin and the coal slurry preparation cabin are respectively provided with a flexible expansion plate, and the top surface and the bottom surface between the coal slurry preparation cabin and the coal slurry storage cabin are respectively provided with a flexible expansion plate.

Furthermore, a cutter disc set is arranged on the front end face of the tunneling crushing cabin, a main cutter disc and an auxiliary cutter disc are arranged on the front side face of the cutter disc set, and a main cutter disc driving device and an auxiliary cutter disc driving device are arranged on the rear side face of the cutter disc set.

Further, a screw conveyor, a coal crushing chamber and a crushing chamber hydraulic station are arranged in the tunneling crushing chamber, and the screw conveyor is positioned in front of the coal crushing chamber and communicated with the coal crushing chamber; the crushing cabin hydraulic station is respectively connected with the main cutter driving device and the auxiliary cutter driving device.

Furthermore, a grinding chamber, a coal slurry mixing chamber, a catalyst storage chamber, a water storage tank and a coal slurry preparation chamber hydraulic station are arranged in the coal slurry preparation chamber, the front end of the grinding chamber is connected with the coal crushing chamber through a coal conveying pipeline, the rear end of the grinding chamber is connected with the coal slurry mixing chamber, and the coal slurry mixing chamber is respectively connected with the catalyst storage chamber and the water storage tank through a catalyst input pipeline and a clean water input pipeline; the coal slurry preparation cabin hydraulic station is connected with the front hydraulic cylinder; the catalyst storeroom and the water storage tank respectively extend to the rear part of the coal slurry storeroom through a catalyst supply pipeline and a clear water supply pipeline.

Further, a coal slurry storage chamber, a coal slurry pump and a coal slurry storage chamber hydraulic station are arranged inside the coal slurry storage chamber, the coal slurry storage chamber is connected with the coal slurry mixing chamber through a coal slurry conveying pipeline, and the coal slurry pump is arranged at the rear end of the coal slurry storage chamber; the hydraulic station of the coal slurry storage cabin is connected with the rear hydraulic cylinder.

Furthermore, fluidization pipeline conveyor is vertical multistage formula structure, and each section includes coal slurry elevator pump, spinner, coal slurry lifting pipeline and coal slurry transfer cabin, and coal slurry transfer cabin sets up in the other country rock of vertical shaft, and upper and lower two adjacent coal slurry transfer cabins pass through coal slurry lifting pipeline intercommunication, are equipped with coal slurry elevator pump, spinner on the coal slurry lifting pipeline.

Compared with the prior art, the fluidized mining equipment comprises a tunneling crushing cabin, a coal slurry preparation cabin and a coal slurry storage cabin, a hydraulic cylinder is used as a driving part, the tunneling crushing cabin is gradually pushed in a resistance-increasing stepping mode, the stepping self-walking of the fluidized mining equipment is realized, a coal layer mined by the tunneling crushing cabin is conveyed to the coal slurry storage cabin to be made into coal slurry, the coal slurry is stored in the coal slurry storage cabin and conveyed to the ground through an underground transfer station and a multi-section fluidized pipeline conveying device, finally, the green environmental protection target of 'no coal on the ground and no people under the ground' is achieved, and the subversion change of deep coal resource mining is realized; the whole device of the fluidization mining equipment is rectangular, does not need supporting force from the left side and the right side, and can still normally operate even if coal beds on the left side and the right side are mined empty areas; the underground connecting pipelines on the well are all arranged through the vertical shaft, and the cage can be stopped at any time, so that the inspection and the maintenance are convenient.

Drawings

FIG. 1 is a schematic three-dimensional structure of the present invention;

FIG. 2 is a front view of the present invention;

FIG. 3 is an enlarged view of a portion of FIG. 2;

FIG. 4 is a view taken along line C-C of FIG. 3;

FIG. 5 is a cross-sectional elevation view of a roadway of fluidized mining equipment of the present invention;

FIG. 6 is a view taken along line A-A of FIG. 5;

in the figure: 1. fluidized mining equipment; 2. a coal seam; 3. surrounding rocks; 4. an underground transfer station; 5. a cage; 6. a fluidized pipeline transport device; 7. a clear water conveying device; 8. a vertical shaft; 9. a ground surface; 10. a winch house; 11. a head frame; 12-1, a front hydraulic cylinder; 12-2, a rear hydraulic cylinder; 13. a ground slurry storage station; 101. a cutter disc set; 102. tunneling a crushing cabin; 103. a coal slurry preparation cabin; 104. a coal slurry storage bin; 601. a coal slurry lift pump; 602. a spinner; 603. a coal slurry lifting pipeline; 604. a coal slurry transfer chamber; 701. a clear water delivery conduit; 702. a ground water supply station; 1011. a main cutter head; 1012. an auxiliary cutter head; 1013. a main cutter head driving device; 1014. an auxiliary cutter head driving device; 1021. a screw conveyor; 1022. a coal crushing chamber; 1023. a crushing cabin hydraulic station; 1024. tunneling a power supply station of the crushing cabin; 1025. a coal delivery pipeline; 1026. a flexible expansion plate; 1031. a grinding chamber; 1032. a coal slurry mixing chamber; 1033. a catalyst storage chamber; 1034. a water storage tank; 1035. a coal slurry preparation cabin hydraulic station; 1036. a power supply station of the coal slurry preparation cabin; 1041. a coal slurry storage chamber; 1042. a coal slurry pump; 1043. a slurry storage tank hydraulic station; 1044. a coal slurry storage cabin power supply station; 10321. a coal slurry delivery conduit; 10331. a catalyst input conduit; 10332. a catalyst supply line; 10341. clear water input pipeline; 10342. a clear water supply pipeline.

Detailed Description

The invention will be further explained with reference to the drawings.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a technical scheme that: as shown in fig. 1 and 2, the system comprises fluidization mining equipment 1, a cage 5, a winch house 10, a head sheave 11, a ground coal slurry storage station 13, a downhole transfer station 4, a fluidization pipeline conveying device 6 and a clean water conveying device 7; the winch house 10 is arranged on the ground 9, the head sheave 11 is arranged on the vertical shaft 8, the cage 5 is positioned in the vertical shaft 8, a winch rope at the top of the cage 5 is connected into the winch house 10 through the head sheave 11, the winch house 10 controls the cage 5 to move up and down in the vertical shaft 8, the cage 5 can be stopped at any time, and the fluidized pipeline conveying device 6 and the clear water conveying device 7 can be conveniently checked and maintained; a surface slurry storage station 13 is disposed on the surface 9 adjacent to the shaft 8 for storing the slurry transported downhole.

The underground transfer station 4 is arranged in the surrounding rock 3 at the bottom of the vertical shaft 8, the fluidization pipeline conveying device 6 is arranged in the vertical shaft 8, the bottom end of the fluidization pipeline conveying device 6 is communicated with the underground transfer station 4, and the top end of the fluidization pipeline conveying device 6 is communicated with the ground coal slurry storage station 13; the underground transfer station 4 is used as a medium for connecting the underground and the ground and supplies water, catalyst and electric energy to the fluidized mining equipment 1.

As shown in fig. 3, the fluidization conduit transportation device 6 is a longitudinal multi-section structure, each section includes a slurry lift pump 601, a rotation starter 602, a slurry lift conduit 603 and a slurry transfer chamber 604, the slurry transfer chamber 604 is disposed in the surrounding rock 3 beside the vertical shaft 8, the upper and lower adjacent slurry transfer chambers 604 are communicated through the slurry lift conduit 603, the slurry lift conduit 603 is disposed on a side surface of the slurry transfer chamber 604 close to the vertical shaft 8, and the slurry lift pump 601 and the rotation starter 602 are disposed on the slurry lift conduit 603; the coal slurry transfer chamber 604 positioned at the uppermost position is connected with the ground coal slurry storage station 13 through a coal slurry lifting pipe 603, and the coal slurry transfer chamber 604 positioned at the lowermost position is connected with the underground transfer station 4 through the coal slurry lifting pipe 603.

The clean water conveying device 7 comprises a ground water supply station 702 and a clean water conveying pipeline 701, the ground water supply station 702 is arranged on the ground 9 beside the vertical shaft 8, as shown in fig. 4, the clean water conveying pipeline 701 is positioned in the vertical shaft 8 and is communicated with the underground transfer station 4 and the ground water supply station 702; water in the surface water supply station 702 is delivered to the downhole transfer station 4 through a clean water delivery pipe 701.

As shown in fig. 5 and 6, the fluidized mining equipment 1 is positioned in a coal seam 2, the fluidized mining equipment 1 comprises a tunneling crushing cabin 102, a coal slurry preparation cabin 103 and a coal slurry storage cabin 104, the rear side edge of the tunneling crushing cabin 102 is connected with the front side edge of the coal slurry preparation cabin 103 through a front hydraulic cylinder 12-1, and the rear side edge of the coal slurry preparation cabin 103 is connected with the front side edge of the coal slurry storage cabin 104 through a rear hydraulic cylinder 12-2; flexible expansion plates 1026 are respectively arranged on the top surface and the bottom surface between the tunneling crushing cabin 102 and the coal slurry preparation cabin 103, and the flexible expansion plates 1026 are respectively arranged on the top surface and the bottom surface between the coal slurry preparation cabin 103 and the coal slurry storage cabin 104; the front hydraulic cylinder 12-1 and the rear hydraulic cylinder 12-2 work together to drive the tunneling crushing cabin 102, the coal slurry preparation cabin 103 and the coal slurry storage cabin 104 to move forwards.

A cutter disc group 101 is arranged on the front end face of the tunneling and crushing cabin 102, a main cutter disc 1011 and an auxiliary cutter disc 1012 are arranged on the front side face of the cutter disc group 101, and a main cutter disc driving device 1013 and an auxiliary cutter disc driving device 1014 for driving the main cutter disc 1011 and the auxiliary cutter disc 1012 are arranged on the rear side face of the cutter disc group 101;

the tunneling crushing cabin 102 is also internally provided with a spiral conveyor 1021, a coal crushing chamber 1022, a crushing cabin hydraulic station 1023 and a tunneling crushing cabin power supply station 1024, wherein the spiral conveyor 1021 is positioned in front of the coal crushing chamber 1022 and is communicated with the coal crushing chamber 1022; the crushing cabin hydraulic station 1023 is respectively connected with the main cutter head driving device 1013 and the auxiliary cutter head driving device 1014, and provides power for the main cutter head driving device 1013 and the auxiliary cutter head driving device 1014; the tunneling crushing cabin power supply station 1024 supplies electric energy to electric equipment such as the screw conveyor 1021 and the coal crushing chamber 1022.

A grinding chamber 1031, a coal slurry mixing chamber 1032, a catalyst storage chamber 1033, a water storage tank 1034, a coal slurry preparation chamber hydraulic station 1035 and a coal slurry preparation chamber power supply station 1036 are arranged in the coal slurry preparation chamber 103, the front end of the grinding chamber 1031 is connected with the coal crushing chamber 1022 through a coal conveying pipeline 1025, the rear end of the grinding chamber 1031 is connected with the coal slurry mixing chamber 1032, and the coal slurry mixing chamber 1032 is respectively connected with the catalyst storage chamber 1033 and the water storage tank 1034 through a catalyst input pipeline 10331 and a clean water input pipeline 10341; the coal slurry preparation cabin hydraulic station 1035 is connected with the front hydraulic cylinder 12-1 to provide power for the front hydraulic cylinder 12-1; the power supply station 1036 of the coal slurry preparation cabin supplies electric energy to electric equipment such as the grinding chamber 1031 and the coal slurry mixing chamber 1032; the catalyst storage 1033 and the water storage 1034 extend to the rear of the coal slurry storage 1041 through a catalyst supply pipe 10332 and a clean water supply pipe 10342, respectively.

The coal slurry storage chamber 1041, the coal slurry pump 1042, the coal slurry storage chamber hydraulic station 1043 and the coal slurry storage chamber power supply station 1044 are arranged inside the coal slurry storage chamber 104, the coal slurry storage chamber 1041 is connected with the coal slurry mixing chamber 1032 through a coal slurry conveying pipeline 10321, and the coal slurry pump 1042 is arranged at the rear end of the coal slurry storage chamber 1041; the coal slurry storage cabin hydraulic station 1043 is connected with the rear hydraulic cylinder 12-2 to provide power for the rear hydraulic cylinder 12-2; the coal slurry storage cabin power supply station 1044 provides electric energy for electric equipment such as a coal slurry pump 1042 and the like.

The coal conveying pipeline 1025, the flexible expansion plate 1026, the coal slurry conveying pipeline 10321, the catalyst supply pipeline 10332 and the clear water supply pipeline 10342 are all retractable devices; the relative movement of the tunneling crushing chamber 102, the coal slurry preparation chamber 103 and the coal slurry storage chamber 104 can be unaffected.

When the tunneling crushing cabin 102 reaches the maximum stroke, the coal slurry storage cabin 104 pushes the coal slurry preparation cabin 103 again, and the tunneling crushing cabin 102 pulls the coal slurry preparation cabin 103 at the same time, so that the coal slurry preparation cabin 103 also completes a stepping action; then the coal slurry preparation cabin 103 pulls the coal slurry storage cabin 104, and the whole deep coal fluidization mining equipment 1 completes one-time autonomous walking process; if the extension of the right hydraulic cylinder in the front propelling device 6 and the rear propelling device 10 is larger than that of the left hydraulic cylinder, the whole self-walking mechanism turns to the left, and if the extension of the left hydraulic cylinder in the front propelling device 6 and the rear propelling device 10 is larger than that of the right hydraulic cylinder, the whole self-walking mechanism turns to the right. Because the whole device is rectangular, supporting force from the left side and the right side is not needed, and the coal seam can still normally run even if the left side and the right side are mined empty areas.

The coal seam 2 of the front mining area to be mined enters a coal crushing chamber 1022 through a spiral conveyor 1021 after being mined through a cutter disc group 101, crushed coal blocks are conveyed to a grinding chamber 1031 through a coal conveying pipeline 1025, become coal particles with smaller particle sizes after passing through the grinding chamber 1031, are mixed with a catalyst in a catalyst storage chamber 1033 and clean water in a water storage tank 1034 to form coal slurry in a coal slurry mixing chamber 1032, and are conveyed to a coal slurry storage chamber 1041 through a coal slurry conveying pipeline 10321, when the fluidized mining equipment 1 passes through the underground transfer station 4 every time, a catalyst supply pipeline 10332 and a clean water supply pipeline 10342 in a coal slurry storage chamber 104 are communicated with the underground transfer station 4 to supply catalyst, water and electric energy to the catalyst storage chamber 1033 and the water storage tank 1034, and meanwhile, a coal slurry pump 1042 is communicated with the underground transfer station 4 through pipelines to output the coal slurry to the underground transfer station 4. The coal slurry in the underground transfer station 4 is then conveyed to the ground coal slurry storage station 13 on the ground in a vertical lifting mode through a plurality of coal slurry transfer cabins 604 of the coal slurry lifting device 6, and the ground water supply station 702 provides water resources underground.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and any minor modifications, equivalent replacements and improvements made to the above embodiment according to the technical spirit of the present invention should be included in the protection scope of the technical solution of the present invention.