阅读说明：本技术 基于集成冷却系统的超临界二氧化碳膨胀机 (Supercritical carbon dioxide expander based on integrated cooling system ) 是由 郭朝红 姜玉雁 郭永献 梁世强 陈俊斌 朱玉铭 于 2020-04-23 设计创作，主要内容包括：本公开提供一种基于集成冷却系统的超临界二氧化碳膨胀机,包括：转子部,包括：透平,主轴,以及干气密封动部件；机壳部,环转子部外设置,包括：蜗壳,干气密封静部件,环干气密封动部件设置,其外固接密封机壳；隔热机壳,与干气密封动部件之间形成一第一环形间隙,与主轴之间形成一第二环形间隙,与透平之间形成一第三环形间隙；以及冷却环套,环隔热机壳表面设置,用于引入一定流量的高压低温的超临界二氧化碳,在冷却环套内进行流动换热,以及密封气通道,用于将从冷却环套出口排出后经密封器调控系统调整后的二氧化碳从密封气通道入口输入第一环形间隙,再流经第二环形间隙后流至第三环形间隙,实现转子部与机壳部的同时串联冷却。(The present disclosure provides an integrated cooling system based supercritical carbon dioxide expander, comprising: a rotor portion comprising: a turbine, a main shaft, and a dry gas seal dynamic component; the casing portion, the outer setting of ring rotor portion includes: the volute, the dry gas seal static part and the annular dry gas seal dynamic part are arranged, and the outside of the volute is fixedly connected with a seal machine shell; the heat insulation casing forms a first annular gap with the dry gas sealing dynamic part, forms a second annular gap with the main shaft and forms a third annular gap with the turbine; the cooling ring sleeve is arranged on the surface of the heat insulation engine shell and used for introducing high-pressure low-temperature supercritical carbon dioxide with a certain flow rate to perform flowing heat exchange in the cooling ring sleeve, and the sealing air channel is used for inputting the carbon dioxide which is discharged from an outlet of the cooling ring sleeve and adjusted by the sealer adjusting and controlling system into the first annular gap from an inlet of the sealing air channel, then flows into the third annular gap after flowing through the second annular gap, so that the rotor part and the shell part are simultaneously cooled in series.)

1. An integrated cooling system based supercritical carbon dioxide expander comprising:

a rotor portion comprising:

a turbine;

one end of the main shaft is connected with the turbine; and

the dry air sealing dynamic part is arranged at the other end of the main shaft;

the casing portion, the outer setting of ring rotor portion includes:

the volute is arranged on the periphery of the turbine;

the dry gas seal static part is arranged around the dry gas seal dynamic part, and the outer part of the dry gas seal static part is fixedly connected with a seal machine shell;

the heat insulation casing is arranged between the volute and the sealing casing, forms a first annular gap with the dry gas sealing dynamic component, forms a second annular gap with the main shaft, and forms a third annular gap with the turbine; and

the cooling ring sleeve is arranged on the surface of the ring sealing machine shell and used for conveying carbon dioxide and cooling the sealing machine shell, a cooling ring sleeve inlet and a cooling ring sleeve outlet are arranged at opposite positions of the cooling ring sleeve, the cooling ring sleeve inlet is used for introducing high-pressure low-temperature supercritical carbon dioxide with a certain flow rate from the side of the compressor, flow heat exchange is carried out in the cooling ring sleeve, and the cooled sealing machine shell is discharged from the cooling ring sleeve outlet; and

and the sealing gas channel is used for inputting carbon dioxide which is discharged from the outlet of the cooling ring sleeve and is adjusted by the sealer adjusting and controlling system into the first annular gap from the inlet of the sealing gas channel, and then flows into the third annular gap after flowing through the second annular gap, so that the rotor part and the shell part are simultaneously cooled in series.

2. The integrated cooling system based supercritical carbon dioxide expander of claim 1, the seal gas control system comprising:

the storage tank is connected with the outlet of the cooling ring sleeve and is used for stabilizing the pressure of the discharged carbon dioxide fluid;

the pressure regulating module is used for regulating the pressure of the carbon dioxide fluid and comprises three fluid pipelines which are arranged in parallel, wherein any two pipelines are respectively provided with a throttling and pressure reducing device and a booster pump, and each fluid pipeline is respectively provided with a stop valve;

the heat exchanger is used for adjusting the temperature of the carbon dioxide according to the cooling requirement and then flowing into the first annular gap of the expansion machine through the inlet of the sealed gas channel; and

and the flow regulating valve is used for regulating and controlling the flow of the sealing gas.

3. The integrated cooling system based supercritical carbon dioxide expander according to claim 1, said turbine comprising: either a radial inflow impeller or an axial flow impeller.

4. The integrated cooling system based supercritical carbon dioxide expander according to claim 1, said turbine structure being a single stage structure or a multi-stage structure.

5. The integrated cooling system based supercritical carbon dioxide expander according to claim 1, wherein said sealed enclosure and dry gas sealed stationary components are joined together by bolted fastening components.

6. The integrated cooling system based supercritical carbon dioxide expander according to claim 1, wherein said cooling collar is disposed on a surface of a sealed enclosure.

7. The integrated cooling system based supercritical carbon dioxide expander of claim 1, the sealer conditioning system for regulating at least one of pressure, temperature or flow of carbon dioxide.

8. The integrated cooling system based supercritical carbon dioxide expander according to claim 1, wherein the seal gas channel feeds carbon dioxide exiting the cooling annulus outlet directly from the seal gas channel inlet into the first annular gap without flow and/or pressure regulation.

9. The integrated cooling system based supercritical carbon dioxide expander of claim 1, the seal gas control system comprising:

the storage tank is connected with the outlet of the cooling ring sleeve and is used for stabilizing the pressure of the discharged carbon dioxide fluid; and

and the heat exchanger is used for adjusting the temperature of the carbon dioxide according to the cooling requirement and then flowing into the first annular gap of the expander through the inlet of the sealed gas channel.

Technical Field

The disclosure relates to the technical field of turbine power generation, in particular to a supercritical carbon dioxide expander based on an integrated cooling system.

Background

The supercritical carbon dioxide (SCO2) turbine power generation technology is a novel power generation technology which takes CO2 in a supercritical state as a working medium and converts heat energy into electric energy through a turbine machine, is suitable for power generation or power conversion of various heat sources, and has wide application prospects in the fields of thermal power, nuclear power, solar power generation and the like. The SCO2 power generation equipment has the characteristics of high energy conversion efficiency and compact structure form, and the advantages thereof have attracted extensive attention.

The SCO2 expander has the characteristics of high speed, high temperature, high energy density and high compactness, high-temperature and high-pressure working media flow through a turbine, heat can be axially transferred through a rotor and a shell, and the SCO2 expander is very compact, the distance between the turbine and parts such as a seal, a bearing, a motor and the like is very short, and the turbine is easy to fail and damage due to high temperature, so that a set of cooling and heat insulation system is required to be equipped to realize the high-temperature heat insulation effect of the turbine in a limited space.

At present, there is a data to indicate that an air pipeline is filled between a turbine and a seal, and the seal and a bearing are cooled by an air injection system (for example, patent "a turbine generator set using supercritical carbon dioxide as a working medium", publication No. CN106014509A), but the additional addition of the air injection system and corresponding temperature and pressure regulation equipment makes the turbine set structure more complicated, and also increases the length of a main shaft to a certain extent, which affects the vibration performance of the main shaft. In addition, in the patent "supercritical carbon dioxide brayton cycle power component cooling, sealing and heat insulating system" (publication number CN208564662U), for a coaxial integrated structure of a compressor, a motor and an expander, a structure for cooling and isolating by utilizing leakage gas at the back of a compressor impeller is proposed: the compressor leaks the gas and passes through the annular clearance between casing and the main shaft after, reaches the isolation ring chamber at expander impeller back, leaks the gas mixture back with the expander and discharges, plays the cooling isolation effect, and its does not have additional cooling system, has reduced the complexity of unit, nevertheless because the flow of compressor leaks the gas less, so the cooling effect is difficult to guarantee, to working medium at the supercritical carbon dioxide turbine above 200 ℃, can't satisfy the cooling requirement. In addition, the above prior art can only realize cooling of the main shaft, and cannot simultaneously meet the cooling requirement of the casing, so that a cooling and heat insulation method which is efficient, simple and compact in structure, and capable of simultaneously meeting the heat conduction problems of the rotor and the casing is urgently needed to be provided for the supercritical carbon dioxide turbine with a compact structure.

BRIEF SUMMARY OF THE PRESENT DISCLOSURE

Technical problem to be solved

Based on the above problem, the present disclosure provides a supercritical carbon dioxide expander based on integrated cooling system to alleviate the technical problems such as the turbine unit structure is comparatively complicated when the cooling of sealing and bearing is realized through the gas injection system among the prior art, or the cooling effect is relatively poor when utilizing compressor leakage gas to cool off and keep apart.

(II) technical scheme

The present disclosure provides an integrated cooling system based supercritical carbon dioxide expander, comprising: a rotor portion comprising: a turbine; one end of the main shaft is connected with the turbine; the dry air sealing dynamic part is arranged at the other end of the main shaft; the casing portion, the outer setting of ring rotor portion includes: the volute is arranged on the periphery of the turbine; the dry gas seal static part is arranged around the dry gas seal dynamic part, and the outer part of the dry gas seal static part is fixedly connected with a seal machine shell; the heat insulation casing is arranged between the volute and the sealing casing, forms a first annular gap with the dry gas sealing dynamic component, forms a second annular gap with the main shaft, and forms a third annular gap with the turbine; the cooling ring sleeve is arranged on the surface of the ring sealing machine shell and used for conveying carbon dioxide and cooling the sealing machine shell, a cooling ring sleeve inlet and a cooling ring sleeve outlet are arranged at opposite positions of the cooling ring sleeve, the cooling ring sleeve inlet is used for introducing high-pressure low-temperature supercritical carbon dioxide with a certain flow rate from the side of the compressor or other proper positions of the system, flowing heat exchange is carried out in the cooling ring sleeve, and the cooled sealing machine shell is discharged from the cooling ring sleeve outlet; and the sealing gas channel is used for inputting the carbon dioxide which is discharged from the outlet of the cooling ring sleeve and is adjusted by the sealer adjusting and controlling system into the first annular gap from the inlet of the sealing gas channel, and then flows to the third annular gap after flowing through the second annular gap, so that the rotor part and the shell part are simultaneously cooled in series.

In an embodiment of the present disclosure, the seal gas control system includes: the storage tank is connected with the outlet of the cooling ring sleeve and is used for stabilizing the pressure of the discharged carbon dioxide fluid; the pressure regulating module is used for regulating the pressure of the carbon dioxide fluid and comprises three fluid pipelines which are arranged in parallel, wherein any two pipelines are respectively provided with a throttling and pressure reducing device and a booster pump, and each fluid pipeline is respectively provided with a stop valve; the heat exchanger is used for adjusting the temperature of the carbon dioxide according to the cooling requirement and then flowing into the first annular gap of the expansion machine through the inlet of the sealed gas channel; and the flow regulating valve is used for regulating and controlling the flow of the sealing gas.

In an embodiment of the present disclosure, the turbine includes: either a radial inflow impeller or an axial flow impeller.

In the disclosed embodiment, the turbine structure is a single stage structure or a multi-stage structure.

In the disclosed embodiment, the sealed casing and the dry gas sealed static part are connected together through a bolt fastening part.

In the embodiment of the disclosure, the cooling collar is arranged on the surface of the sealed casing.

In embodiments of the present disclosure, the sealer conditioning system is used to regulate at least one of the pressure, temperature, or flow of carbon dioxide.

In an embodiment of the disclosure, the seal gas channel feeds carbon dioxide after exiting the cooling collar outlet directly from the seal gas channel inlet into the first annular gap without flow and/or pressure regulation.

In an embodiment of the present disclosure, the seal gas control system includes: the storage tank is connected with the outlet of the cooling ring sleeve and is used for stabilizing the pressure of the discharged carbon dioxide fluid; and the heat exchanger is used for adjusting the temperature of the carbon dioxide according to the cooling requirement and then flowing into the first annular gap of the expander through the inlet of the sealed gas channel.

(III) advantageous effects

From the technical scheme, the supercritical carbon dioxide expander based on the integrated cooling system has at least one or part of the following advantages:

(1) the system can realize two purposes of one set of system, has simpler structure and higher integration level, and is beneficial to improving the compactness of the unit;

(2) the cooling device realizes series cooling of the casing and the main shaft, reduces heating power consumption of the sealed air control system by utilizing casing heating, can meet cooling requirements of the casing and a shaft system, and simplifies a cooling system.

Drawings

Fig. 1 is a schematic cross-sectional structure diagram of a supercritical carbon dioxide expander based on an integrated cooling system according to an embodiment of the disclosure.

Fig. 2 is a schematic diagram of a component architecture of a seal gas control system according to an embodiment of the disclosure.

Fig. 3 is a schematic cross-sectional view of another supercritical carbon dioxide expander based on an integrated cooling system according to an embodiment of the disclosure.

[ description of main reference numerals in the drawings ] of the embodiments of the present disclosure

101-turbine;

102-dry gas seal dynamic components;

103-a main shaft;

201-a volute;

202-a thermally insulated enclosure;

203-sealing the enclosure;

204-dry gas seal static parts;

205-cooling the collar;

301-a first annular gap;

302-a second annular gap;

303-a third annular gap;

401-a storage tank;

402-a throttling pressure reduction device;

403-a booster pump;

404-a heat exchanger;

405-a flow regulating valve;

406-408-stop valve;

a-sealing the gas channel inlet;

b1-cooling collar inlet;

b2-cooling collar outlet.

Detailed Description

The utility model provides a supercritical carbon dioxide expander based on integrated cooling system, specifically be the structure of the turbo expander that working medium is supercritical carbon dioxide and cooling system's design, adopt the integrative cooling scheme of casing, shafting, with the integrated design of dry gas seal system, need not additionally draw sealed gas, reduce redundant miscellaneous equipment, the structure is compacter, and cooling gas flow, pressure, temperature can be adjusted simultaneously, satisfy the cooling requirement of casing and shafting.

For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings.

In an embodiment of the present disclosure, there is provided an integrated cooling system based supercritical carbon dioxide expander, as shown in fig. 1, comprising:

a rotor portion comprising:

a turbine 101;

a main shaft 103 having one end connected to the turbine 101; and

and a dry gas seal pneumatic member 102 provided at the other end of the main shaft 103.

The casing portion, the outer setting of ring rotor portion includes:

a volute 201 arranged at the periphery of the turbine;

a dry gas seal static part 204 arranged around the dry gas seal dynamic part 102, wherein the dry gas seal static part 204 is fixedly connected with a seal casing 203;

the heat insulation casing 202 is arranged between the volute 201 and the sealing casing 203, and forms a first annular gap 301 with the dry gas sealing dynamic component 102; a second annular gap 302 is formed between the main shaft 103 and the turbine 101, and a third annular gap 303 is formed between the main shaft and the turbine 101;

the cooling ring sleeve 205 is arranged on the surface of the ring machine shell 203 and used for conveying carbon dioxide and cooling the sealed machine shell 203, a cooling ring sleeve inlet B1 and a cooling ring sleeve outlet B2 are arranged at opposite positions of the cooling ring sleeve 205, the cooling ring sleeve inlet B1 is used for introducing certain flow of high-pressure low-temperature supercritical carbon dioxide from the side of a compressor or other proper positions of a system, flowing heat exchange is carried out in the cooling ring sleeve 205, and the cooled sealed machine shell 203 is discharged from the cooling ring sleeve outlet B2; and

and the sealing gas channel is used for inputting carbon dioxide which is discharged from the cooling ring sleeve outlet B2 and adjusted by the sealer adjusting and controlling system into the first annular gap 301 from the sealing gas channel inlet A, then flows through the second annular gap 302 and flows to the third annular gap 303, and the simultaneous series connection cooling of the rotor part and the shell part is realized.

The turbine includes: a radial inflow impeller or an axial inflow impeller.

The turbine structure is a single-stage structure or a multi-stage structure.

The sealing case 203 and the dry gas sealing static part 204 are connected together by fastening parts such as bolts.

The seal is generally placed between the turbine and the bearing to avoid the leakage gas from damaging the working environment of the bearing. Both the dry gas seal and the bearings have temperature limitations so that cooling insulation must be achieved between the turbine 101 and the dry gas seal 102. The specific cooling process is as follows: introducing a certain flow of high-pressure low-temperature supercritical carbon dioxide fluid from the compressor side or other suitable position of the system, and flowing into the cooling ring sleeve 205 from the cooling ring sleeve inlet B1, thereby performing heat convection on the sealed shell 203 to cool the shell; and then the gas enters a cooling ring sleeve outlet B2 to flow out of the cooling ring sleeve 205, and then enters an external seal gas regulation system to regulate the pressure, temperature and flow rate of the gas, and then the gas enters a seal gas channel inlet A as dry gas seal gas, wherein a small part of the seal gas leaks out after being throttled by a friction pair, and most of the seal gas flows into a first annular gap 301, then flows into a third annular gap 303 at the turbine side through a second annular gap 302, is mixed with turbine inlet fluid, is discharged after acting in the turbine, and can also be discharged through a drainage hole in the heat insulation casing 202. The flow of seal gas in the first annular gap 301 may cool and isolate the dry gas seal dynamic and static components 102, 204, the flow in the second annular gap 302 may directly convectively cool the main shaft 103, and the flow in the third annular gap 303 may cool and isolate the insulated enclosure 202.

The sealing gas control system heats the sealing gas to a certain temperature, so that the sealing gas can be prevented from freezing after being throttled by the friction pair.

In an embodiment of the present disclosure, as shown in fig. 2, the seal gas control system includes:

a storage tank 401 connected to the cooling jacket outlet B2 for stabilizing the pressure of the discharged carbon dioxide fluid;

the pressure regulating module comprises three fluid pipelines which are arranged in parallel, wherein any two pipelines are respectively provided with a throttling pressure reducing device 402 and a booster pump 403, and each fluid pipeline is respectively provided with a stop valve (a stop valve 406, a stop valve 407 and a stop valve 408);

a heat exchanger 404 for adjusting the temperature of the carbon dioxide according to the cooling requirement and then flowing into the first annular gap 301 of the expander through the inlet a of the sealed gas passage;

and a flow regulating valve 405 for regulating the flow of the seal gas.

The supercritical carbon dioxide after the cooling shell flows out of the cooling ring sleeve outlet B2 enters a sealed air control system, after being stabilized by the storage tank 401, the supercritical carbon dioxide can be pressurized by a booster pump 403 according to the flowing requirement, or the supercritical carbon dioxide is depressurized by a throttling depressurization device 402, or the supercritical carbon dioxide directly flows to a heat exchanger 404 without being regulated in pressure, the temperature is regulated according to the cooling requirement, and finally the regulated sealed air flows into the sealed shell through a channel A. The sealing gas can maintain a sealed clean environment and has a cooling function. The flow regulating valve 405 is used to regulate the flow of the sealing gas entering the enclosure; when the stop valve 406 is opened and the stop valves 407 and 408 are closed, the seal gas is not pressure-regulated; when the stop valves 406 and 408 are closed and the stop valve 407 is opened, the seal gas is pressurized by the booster pump 403; the shutoff valves 406, 407 are closed, and the shutoff valve 408 is opened, the seal gas is depressurized through the throttling depressurizing device 402.

In fig. 1, the seal gas is communicated with the turbine inlet working medium after passing through the annular gaps 301, 302 and 303, and in addition, can also be communicated with the working medium after acting at the turbine outlet, as shown in fig. 3: the cooling gas passes through the annular gaps 301 and 302 and then radially flows into the working medium outlet annular cavity, and is mixed with the outlet working medium and then discharged.

The flow and temperature of cooling gas required by cooling and the requirements of flow, pressure, temperature and the like required by sealing gas are comprehensively considered, the parameters of the supercritical carbon dioxide at the inlet B1 of the cooling ring sleeve are optimally designed, the supercritical carbon dioxide can directly flow into the channel A without regulating the flow and the pressure, and a sealing gas control system is simplified. The flow rate regulating valve 405, the shutoff valve 406, the shutoff valve 407, the shutoff valve 408, and the throttle pressure reducing device 402 and the booster pump 403 in fig. 2 may be omitted.

The present disclosure introduces the heated supercritical carbon dioxide passing through the housing cooling collar 205 into the sealing system as a sealing gas (wind), which can reduce the heating power consumption. In addition, because the flow of the seal gas does not affect the sealing effect of the dry gas seal, the flow of the seal gas can be determined according to the cooling requirements of the machine shell and the main shaft. The cooling system is greatly simplified by integrating the cooling gas and the dry gas sealing control system.

So far, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. It is to be noted that, in the attached drawings or in the description, the implementation modes not shown or described are all the modes known by the ordinary skilled person in the field of technology, and are not described in detail. Further, the above definitions of the various elements and methods are not limited to the various specific structures, shapes or arrangements of parts mentioned in the examples, which may be easily modified or substituted by those of ordinary skill in the art.

From the above description, those skilled in the art should have a clear understanding of the supercritical carbon dioxide expander based on an integrated cooling system of the present disclosure.

In conclusion, the supercritical carbon dioxide expansion machine based on the integrated cooling system is provided, the cooling gas and the dry gas sealing system are integrated, two purposes of one set of system are achieved, the system structure is simpler, the integration level is higher, and the improvement of the compactness of the machine set is facilitated. The cooling device realizes series cooling of the casing and the main shaft, reduces heating power consumption of the sealed air control system by utilizing casing heating, can meet cooling requirements of the casing and a shaft system, and simplifies a cooling system.

It should also be noted that directional terms, such as "upper", "lower", "front", "rear", "left", "right", and the like, used in the embodiments are only directions referring to the drawings, and are not intended to limit the scope of the present disclosure. Throughout the drawings, like elements are represented by like or similar reference numerals. Conventional structures or constructions will be omitted when they may obscure the understanding of the present disclosure.

And the shapes and sizes of the respective components in the drawings do not reflect actual sizes and proportions, but merely illustrate the contents of the embodiments of the present disclosure. Furthermore, in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Unless otherwise indicated, the numerical parameters set forth in the specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present disclosure. In particular, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about". Generally, the expression is meant to encompass variations of ± 10% in some embodiments, 5% in some embodiments, 1% in some embodiments, 0.5% in some embodiments by the specified amount.

Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify a corresponding element does not by itself connote any ordinal number of the element or any ordering of one element from another or the order of manufacture, and the use of the ordinal numbers is only used to distinguish one element having a certain name from another element having a same name.

In addition, unless steps are specifically described or must occur in sequence, the order of the steps is not limited to that listed above and may be changed or rearranged as desired by the desired design. The embodiments described above may be mixed and matched with each other or with other embodiments based on design and reliability considerations, i.e., technical features in different embodiments may be freely combined to form further embodiments.

Those skilled in the art will appreciate that the modules in the device in an embodiment may be adaptively changed and disposed in one or more devices different from the embodiment. The modules or units or components of the embodiments may be combined into one module or unit or component, and furthermore they may be divided into a plurality of sub-modules or sub-units or sub-components. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where at least some of such features and/or processes or elements are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Also in the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware.

Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various disclosed aspects. However, the disclosed method should not be interpreted as reflecting an intention that: that is, the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, disclosed aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this disclosure.

The above-mentioned embodiments are intended to illustrate the objects, aspects and advantages of the present disclosure in further detail, and it should be understood that the above-mentioned embodiments are only illustrative of the present disclosure and are not intended to limit the present disclosure, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present disclosure should be included in the scope of the present disclosure.