阅读说明：本技术 一种蒸汽锅炉管道压力联动控制系统 (Steam boiler pipeline pressure coordinated control system ) 是由 吕杨 程政 牟洪涛 万芳 刘洪涛 于 2021-08-24 设计创作，主要内容包括：本发明提出了一种蒸汽锅炉管道压力联动控制系统,涉及管道压力控制系统领域。一种蒸汽锅炉管道压力联动控制系统,包括锅炉、压力变送器、继电器模块、进料变频器和控制柜,上述锅炉通过蒸汽管道连通养护棚内部,上述压力变送器安装于上述蒸汽管道内部,上述控制柜连接上述压力变送器,上述继电器模块用于控制上述锅炉的点火端,上述进料变频器用于控制上述锅炉的进料端,上述控制柜分别控制连接上述继电器模块和上述进料变频器。本发明能够调整锅炉的蒸汽出气量,并且减少燃料的消耗,从而满足梁场蒸汽养护需求。(The invention provides a steam boiler pipeline pressure linkage control system, and relates to the field of pipeline pressure control systems. The utility model provides a steam boiler pipeline pressure coordinated control system, includes the boiler, pressure transmitter, relay module, feeding converter and switch board, inside above-mentioned boiler passed through steam conduit intercommunication maintenance canopy, above-mentioned pressure transmitter installed inside above-mentioned steam conduit, above-mentioned pressure transmitter is connected to above-mentioned switch board, above-mentioned relay module is used for controlling the ignition end of above-mentioned boiler, above-mentioned feeding converter is used for controlling the feed end of above-mentioned boiler, above-mentioned switch board is the control connection above-mentioned relay module and above-mentioned feeding converter respectively. The invention can adjust the steam output of the boiler and reduce the fuel consumption, thereby meeting the steam curing requirement of the beam field.)

1. The utility model provides a steam boiler pipeline pressure coordinated control system, its characterized in that, includes boiler, pressure transmitter, relay module, feeding converter and switch board, the boiler passes through inside steam conduit intercommunication maintenance canopy, pressure transmitter install in inside the steam conduit, the switch board is connected pressure transmitter, the relay module is used for control the ignition end of boiler, the feeding converter is used for control the feed end of boiler, the switch board is the control connection respectively relay module with the feeding converter.

2. A steam boiler tube pressure coordinated control system as claimed in claim 1, wherein when said pressure transmitter detects that the tube pressure inside said steam tube is less than 0.01mpa, said control cabinet controls the input frequency of said feeding frequency converter to be 10 hz; when the pipeline pressure is greater than 0.01mpa and less than 0.03mpa, the control cabinet controls the input frequency of the feeding frequency converter to be 5 hz; when the pipeline pressure is greater than 0.03mpa, the control cabinet controls the input frequency of the feeding frequency converter to be 2 hz.

3. A steam boiler pipe pressure coordinated control system as claimed in claim 1, wherein said control cabinet is provided with a serial port for connecting with a display, and said control cabinet is provided with two usb interfaces for connecting with a keyboard and a mouse, respectively.

4. A steam boiler tube pressure coordinated control system as recited in claim 1, comprising an internally threaded sleeve through which said pressure transmitter is mounted to said steam tubes.

5. A steam boiler tube pressure coordinated control system as claimed in claim 1, wherein said feeding frequency converter is provided with frequency control ends for adjusting different input frequencies, said frequency control ends being respectively connected to said control cabinets.

6. A steam boiler tube pressure coordinated control system as claimed in claim 5, wherein said control cabinet is in control connection with the induced draft end of said boiler, said control cabinet controlling the operation of feeding after ignition, stopping feeding after shut off and delaying the shut off of induced draft after shut off through different gears respectively.

7. A steam boiler tube pressure coordinated control system as claimed in claim 6, comprising a switching power supply, said control cabinet being provided with a plurality of said gears by said switching power supply.

8. A steam boiler tube pressure coordinated control system as claimed in claim 1, characterized by comprising a temperature sensor, said temperature sensor is installed inside said curing shed, said temperature sensor is connected with said control cabinet, said control cabinet controls said pressure transmitter to start according to the temperature change detected by said temperature sensor.

9. A steam boiler tube pressure coordinated control system as claimed in claim 1, wherein said control cabinet comprises a boiler controller for controlling said relay module and a pressure feedback controller for controlling said feed frequency converter in response to said pressure transmitter detecting tube pressure inside said steam tubes.

10. A steam boiler pipeline pressure linkage control system according to claim 1, wherein there are a plurality of said boilers, said plurality of said boilers are respectively communicated with the inside of said curing barn, and said control cabinet is used for respectively controlling the start-up of each said boiler according to the pipeline pressure detected by said pressure transmitter.

Technical Field

The invention relates to the field of pipeline pressure control systems, in particular to a steam boiler pipeline pressure linkage control system.

Background

At present, bridge construction in China is in high-speed development, methods of precast beam production and assembly type construction are adopted for bridge superstructure in a common mode, the turnover rate and the production efficiency of a precast site can be improved through factory production, and steam is required to be provided for maintaining precast beam plates in a beam site to guarantee construction quality and construction period. When the maintenance stage is changed, the steam pressure in the pipeline is changed. Therefore, in order to solve the above problems, a control system capable of adjusting the steam output of the boiler and reducing the reasonable consumption of fuel so as to meet the steam curing requirement of the beam yard is needed.

Disclosure of Invention

The invention aims to provide a steam boiler pipeline pressure linkage control system which can adjust the steam output of a boiler and reduce the fuel consumption, thereby meeting the steam maintenance requirement of a beam yard.

The embodiment of the invention is realized by the following steps:

the embodiment of the application provides a steam boiler pipeline pressure coordinated control system, including the boiler, pressure transmitter, the relay module, feeding converter and switch board, inside above-mentioned boiler passed through steam conduit intercommunication maintenance canopy, above-mentioned pressure transmitter installed inside above-mentioned steam conduit, above-mentioned pressure transmitter is connected to above-mentioned switch board, above-mentioned relay module is used for controlling the ignition end of above-mentioned boiler, above-mentioned feeding converter is used for controlling the feed end of above-mentioned boiler, above-mentioned switch board is above-mentioned relay module of control connection and above-mentioned feeding converter respectively.

In some embodiments of the present invention, when the pressure transmitter detects that the pipe pressure inside the steam pipe is less than 0.01mpa, the control cabinet controls the input frequency of the feeding frequency converter to be 10 hz; when the pipeline pressure is greater than 0.01mpa and less than 0.03mpa, the control cabinet controls the input frequency of the feeding frequency converter to be 5 hz; when the pipeline pressure is greater than 0.03mpa, the control cabinet controls the input frequency of the feeding frequency converter to be 2 hz.

In some embodiments of the present invention, the control cabinet is provided with a serial port for connecting a display, and the control cabinet is provided with two usb interfaces for respectively connecting a keyboard and a mouse.

In some embodiments of the present invention, the steam boiler tube pressure linkage control system comprises an internally threaded sleeve, and the pressure transmitter is mounted to the steam tube through the internally threaded sleeve.

In some embodiments of the present invention, the feeding frequency converter is provided with frequency control ends for adjusting different input frequencies, and the frequency control ends are respectively connected to the control cabinet.

In some embodiments of the present invention, the control cabinet is in control connection with an induced draft end of the boiler, and the control cabinet controls operations of ignition after feeding, stopping feeding after shutting down fire, and delaying shutting down induced draft after shutting down fire through different gears respectively.

In some embodiments of the present invention, the steam boiler pipe pressure linkage control system includes a switching power supply, and the control cabinet is provided with a plurality of the gears through the switching power supply.

In some embodiments of the present invention, the steam boiler pipe pressure linkage control system includes a temperature sensor, the temperature sensor is installed inside the curing barn, the temperature sensor is connected to the control cabinet, and the control cabinet controls the pressure transmitter to start according to the temperature change detected by the temperature sensor.

In some embodiments of the present invention, the control cabinet includes a boiler controller for controlling the relay module, and a pressure feedback controller for controlling the feeding frequency converter according to the pipe pressure inside the steam pipe detected by the pressure transmitter.

In some embodiments of the present invention, the number of the boilers is plural, the plural boilers are respectively communicated with the inside of the curing barn, and the control cabinet is used for respectively controlling the start of each boiler according to the pipeline pressure detected by the pressure transmitter.

Compared with the prior art, the embodiment of the invention has at least the following advantages or beneficial effects:

the embodiment of the application provides a steam boiler pipeline pressure coordinated control system, including the boiler, pressure transmitter, the relay module, feeding converter and switch board, inside above-mentioned boiler passed through steam conduit intercommunication maintenance canopy, above-mentioned pressure transmitter installed inside above-mentioned steam conduit, above-mentioned pressure transmitter is connected to above-mentioned switch board, above-mentioned relay module is used for controlling the ignition end of above-mentioned boiler, above-mentioned feeding converter is used for controlling the feed end of above-mentioned boiler, above-mentioned switch board is above-mentioned relay module of control connection and above-mentioned feeding converter respectively.

According to the embodiment of the application, steam generated by the boiler is transmitted to the maintenance shed through the steam pipeline, so that precast beam plates in the maintenance shed are maintained, and the construction quality and the construction period are guaranteed; the pressure transmitter is arranged inside the steam pipeline, so that the pressure inside the steam pipeline is detected and uploaded to the control cabinet. The pressure transmitter can be a high-temperature type pressure transmitter, so that the pressure transmitter is suitable for measuring high-temperature media such as steam; the relay module is used for controlling the ignition or the closing of the boiler, so that fuel in the boiler is combusted, and steam is generated for beam field maintenance; the feeding frequency converter drives the feeding end of the boiler to be opened or closed, so that fuel is added for combustion, the steam generation amount of the boiler is increased, and the maintenance quality of the beam plate is improved; the control cabinet detects the pressure in the steam pipeline according to the pressure transmitter, so that the steam generation amount of the boiler is controlled through ignition of the boiler and the fuel feeding amount, the fuel consumption is greatly reduced, and the operation efficiency is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic diagram of a steam boiler tube pressure coordinated control system according to an embodiment of the present invention;

FIG. 2 is a schematic circuit diagram of a feed frequency converter according to an embodiment of the present invention;

fig. 3 is a schematic circuit diagram of a control cabinet according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. 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 application.

In the description of the present application, it is also to be noted that, unless otherwise explicitly specified or limited, the terms "disposed" and "connected" are to be interpreted broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments described below and the individual features of the embodiments can be combined with one another without conflict.

Examples

Referring to FIG. 1, FIG. 1 is a schematic diagram illustrating a steam boiler tube pressure coordinated control system according to an embodiment of the present invention. Steam boiler pipeline pressure coordinated control system, including the boiler, pressure transmitter, relay module, feeding converter and switch board, inside above-mentioned boiler passed through steam conduit intercommunication maintenance canopy, above-mentioned pressure transmitter installed inside above-mentioned steam conduit, above-mentioned pressure transmitter is connected to above-mentioned switch board, above-mentioned relay module is used for controlling the ignition end of above-mentioned boiler, above-mentioned feeding converter is used for controlling the feed end of above-mentioned boiler, above-mentioned switch board is above-mentioned relay module of control connection and above-mentioned feeding converter respectively.

According to the embodiment of the application, steam generated by the boiler is transmitted to the maintenance shed through the steam pipeline, so that precast beam plates in the maintenance shed are maintained, and the construction quality and the construction period are guaranteed; the pressure transmitter is arranged inside the steam pipeline, so that the pressure inside the steam pipeline is detected and uploaded to the control cabinet. The pressure transmitter can be a high-temperature type pressure transmitter, so that the pressure transmitter is suitable for measuring high-temperature media such as steam; the relay module is used for controlling the ignition or the closing of the boiler, so that fuel in the boiler is combusted, and steam is generated for beam field maintenance; the feeding frequency converter drives the feeding end of the boiler to be opened or closed, so that fuel is added for combustion, the steam generation amount of the boiler is increased, and the maintenance quality of the beam plate is improved; the control cabinet detects the pressure in the steam pipeline according to the pressure transmitter, so that the steam generation amount of the boiler is controlled through ignition of the boiler and the fuel feeding amount, the fuel consumption is greatly reduced, and the operation efficiency is improved.

According to the beam field steam curing demand, the maintenance cycle divide into intensification period, heat preservation period and cooling period, when maintenance canopy quantity (or area) and maintenance stage change, can cause the interior steam pressure of pipeline to change, the feed rate of the adjustment boiler that needs to correspond to the steam gas output of adjustment boiler, with the reasonable consumption that reduces fuel, avoid frequent pressure release.

Optionally, the boiler is a biomass normal-pressure steam boiler, and the pressure transmitter is a high-temperature pressure transmitter capable of detecting the temperature in the high-temperature steam environment. The pressure transmitter is a device which converts pressure into pneumatic signals or electric signals for control and remote transmission, and can convert physical pressure parameters of gas, liquid and the like sensed by the sensor into electric signals to be supplied to secondary instruments such as an indicating alarm instrument, a recorder, a regulator and the like for measurement, indication and process regulation. The sensor adopts a steam high-temperature sensor, and can control the feeding frequency converter according to the steam pressure of the pipeline and output signals so as to realize the adjustment of the steam quantity. The relay module is a high-low voltage relay and is used for controlling whether the stock boiler continuously burns or not. Optionally, when the control cabinet determines that the pressure value of the pipeline pressure is higher than a certain set value, the control cabinet controls the burner to stop providing fuel for combustion, wherein the fuel may be fuel oil. The feeding frequency converter can control the feeding amount by driving a hearth feeding system of the boiler. Utilize boiler pipe internal pressure to measure, can improve control system's sensitivity, open or close boiler feeding and burning fast to guarantee the inside steam environment of maintenance canopy, improve beam yard maintenance quality and efficiency, and fuel saving and combustion energy.

In some embodiments of the present invention, when the pressure transmitter detects that the pipe pressure inside the steam pipe is less than 0.01mpa, the control cabinet controls the input frequency of the feeding frequency converter to be 10 hz; when the pipeline pressure is greater than 0.01mpa and less than 0.03mpa, the control cabinet controls the input frequency of the feeding frequency converter to be 5 hz; when the pipeline pressure is greater than 0.03mpa, the control cabinet controls the input frequency of the feeding frequency converter to be 2 hz.

In detail, when pipeline pressure is less than 0.01mpa, switch higher input frequency through the feeding converter to increase the feeding volume of boiler, improve steam production volume, and then improve the high temperature steam volume and the pressure size in the curing shed, improve precast beam's maintenance quality. When the pipeline pressure is lower, the pipeline pressure is switched to 5hz, so that the energy consumption is further reduced, and a good steam curing environment of the precast beam is ensured. In detail, when the pipeline pressure is greater than 0.03mpa, the control cabinet controls the input frequency of the feeding frequency converter to be 2hz, so that the energy consumption is reduced. The steam quantity can be increased in time by switching the three modes, and the energy consumption is further reduced. Fig. 2 is a schematic circuit diagram of the feeding frequency converter.

In some embodiments of the present invention, the control cabinet is provided with a serial port for connecting a display, and the control cabinet is provided with two usb interfaces for respectively connecting a keyboard and a mouse.

In detail, the control cabinet is displayed by a display, and is convenient to operate by using a keyboard and a mouse, so that each device is managed and controlled. Optionally, the size of the pipeline pressure and the corresponding input frequency after setting different modes can be modified, so as to adapt to different situations.

In some embodiments of the present invention, the steam boiler tube pressure linkage control system comprises an internally threaded sleeve, and the pressure transmitter is mounted to the steam tube through the internally threaded sleeve.

In detail, the model of the internal thread sleeve is M20, the internal thread sleeve is welded on the pipeline firstly, and then the pressure transmitter is connected in a threaded mode, so that the disassembly and maintenance are convenient. Optionally, when the pipeline has a plurality of branches, pressure transmitters can be respectively installed on different branches, and each pressure transmitter is respectively connected with the control cabinet, so that the pressure of different branches can be detected. The pressure of the pipelines is detected through a plurality of branches, so that the positions and the number of the pressure transmitters are utilized to obtain the corresponding input frequency of the frequency converter, the detection sensitivity and accuracy can be improved, the steam quantity of each part of the maintenance tent is more uniform, and the processing efficiency of the precast beam is improved.

In some embodiments of the present invention, the feeding frequency converter is provided with frequency control ends for adjusting different input frequencies, and the frequency control ends are respectively connected to the control cabinet.

In detail, the feeding frequency converter is provided with a frequency control end for adjusting different input frequencies, and the frequency control end is controlled by a control cabinet, so that different input frequencies of the feeding frequency converter can be adjusted by using the pipeline pressure detected by the pressure transmitter, and the operation is convenient.

In some embodiments of the present invention, the control cabinet is in control connection with an induced draft end of the boiler, and the control cabinet controls operations of ignition after feeding, stopping feeding after shutting down fire, and delaying shutting down induced draft after shutting down fire through different gears respectively.

In detail, the opening and closing of the induced air end of the boiler can be realized through an induced draft fan, and the combustion efficiency can be improved through induced air operation after ignition. Optionally, the control cabinet sets delayed ignition after feeding, delayed stopping after turning off fire, and delayed closing of induced air after turning off fire respectively through different gears, wherein the delayed time can be set respectively. The control cabinet controls the ignition and the fire shutoff of the boiler through the relay module, and controls the feeding start and stop through the feeding frequency converter. The boiler damage caused by fuel-free combustion can be avoided by delaying feeding after feeding; the residual heat of combustion can be further consumed by delaying to stop feeding after fire is turned off, so that energy consumption is saved; the air can be further and fully combusted by delaying the closing of the induced air after the fire is shut off, thereby not only saving the heat which is not consumed but also saving the fuel.

In some embodiments of the present invention, the steam boiler pipe pressure linkage control system includes a switching power supply, and the control cabinet is provided with a plurality of the gears through the switching power supply.

In detail, when different gears are automatically controlled through the control cabinet, manual control can be achieved through the switch power supply, and operation is facilitated. Wherein a plurality of gears may correspond to different operations. Optionally, the same gear may correspond to multiple operations.

In some embodiments of the present invention, the steam boiler pipe pressure linkage control system includes a temperature sensor, the temperature sensor is installed inside the curing barn, the temperature sensor is connected to the control cabinet, and the control cabinet controls the pressure transmitter to start according to the temperature change detected by the temperature sensor.

In detail, the temperature sensor is used for sensing the temperature change in the curing shed, and the curing period can be judged according to the temperature change. Because different maintenance periods can cause steam pressure changes, the control cabinet can control the corresponding pressure transmitter to detect when the maintenance stage changes, so that whether ignition and feeding quantity of the boiler are adjusted or not is judged, and further intellectualization and low energy consumption are realized. The boiler is adjusted according to the temperature change, and compared with the time according to the maintenance period and manual operation, the boiler can be more flexibly adapted to the change of the maintenance period, and the automation accuracy is improved.

In some embodiments of the present invention, as shown in fig. 3, the control cabinet includes a boiler controller for controlling the relay module, and a pressure feedback controller for controlling the feeding frequency converter according to the pipe pressure inside the steam pipe detected by the pressure transmitter.

In detail, the boiler controller controls the ignition end of the boiler through the relay module, and the pressure feedback controller receives the pipeline pressure through the pressure transmitter and controls the input frequency of the feeding frequency converter according to the pipeline pressure. Wherein, the boiler controller is connected with the relay module, and the pressure feedback controller is respectively connected with the pressure transmitter and the feeding frequency converter.

Optionally, different gears are set by priority operated between the boiler controller and the pressure feedback controller. In detail, the switch power supply can be a three-gear selection switch, when in ignition, the selection switch is switched to 1 gear, and the boiler controller is used for controlling feeding and then the ignition is carried out (an ignition delay function); after normal operation, the frequency converter is shifted to 2, and a pressure feedback controller is used for controlling the frequency converter according to the pressure of the pipeline; and finally, before the maintenance is finished and flameout is carried out, the selection switch is switched to the 1 st gear, and at the moment, the boiler controller is used for controlling to shut off the fire and then stopping feeding and air induction (the feeding and air induction delay function).

In some embodiments of the present invention, the number of the boilers is plural, the plural boilers are respectively communicated with the inside of the curing barn, and the control cabinet is used for respectively controlling the start of each boiler according to the pipeline pressure detected by the pressure transmitter.

In detail, the number of the boilers may be plural, thereby improving the generation efficiency of the steam. Each boiler can be respectively provided with different pressure transmitters to detect the pipeline pressure. Optionally, the steam pipes of the plurality of boilers can be communicated and then output to the curing shed.

It will be appreciated that the configuration shown in FIG. 1 is merely illustrative and that the steam boiler tube pressure coordinated control system may also include more or fewer components than shown in FIG. 1 or have a different configuration than shown in FIG. 1. The components shown in fig. 1 may be implemented in hardware, software, or a combination thereof.

In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The apparatus embodiments described above are merely illustrative, and for example, the block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present application. In this regard, each block in the block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams, and combinations of blocks in the block diagrams, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

In addition, functional modules in the embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

The functions, if implemented in the form of software functional modules and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

In summary, the steam boiler pipe pressure coordinated control system provided by the embodiment of the present application:

according to the embodiment of the application, steam generated by the boiler is transmitted to the maintenance shed through the steam pipeline, so that precast beam plates in the maintenance shed are maintained, and the construction quality and the construction period are guaranteed; the pressure transmitter is arranged inside the steam pipeline, so that the pressure inside the steam pipeline is detected and uploaded to the control cabinet. The pressure transmitter can be a high-temperature type pressure transmitter, so that the pressure transmitter is suitable for measuring high-temperature media such as steam; the relay module is used for controlling the ignition or the closing of the boiler, so that fuel in the boiler is combusted, and steam is generated for beam field maintenance; the feeding frequency converter drives the feeding end of the boiler to be opened or closed, so that fuel is added for combustion, the steam generation amount of the boiler is increased, and the maintenance quality of the beam plate is improved; the control cabinet detects the pressure in the steam pipeline according to the pressure transmitter, so that the steam generation amount of the boiler is controlled through ignition of the boiler and the fuel feeding amount, the fuel consumption is greatly reduced, and the operation efficiency is improved.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.