阅读说明：本技术 一种防静电地板及制备防静电基材的方法 (Anti-static floor and method for preparing anti-static base material ) 是由 汤德涛 于 2020-12-03 设计创作，主要内容包括：本发明提供了一种防静电地板及制备防静电基材的方法,包括：贴附面板、防静电基材、支撑架,所述贴附面板贴附在所述防静电基材的一个表面上,所述支撑架支撑在所述防静电基材的另一个表面上,所述防静电基材由以下原料按照重量份组成：46-60份水泥、10-15份石粉、5-10份发泡剂、5-10份炭末、3-5份降阻剂、0.5-1份减水剂。本发明实施例提供了一种防静电地板,并对其防静电基材做改进,相较于现有的防静电基材,在本发明的方案中添加了炭末,添加碳末不仅可以提高防静电基材的导电性能,进而提高防静电地板的防静电性能,在此基础上,添加降阻剂,可以进一步减小防静电基材的阻止,进而更进一步的提高防静电地板的防静电性能。(The invention provides an anti-static floor and a method for preparing an anti-static base material, which comprises the following steps: attached panel, prevent static substrate, support frame, attached panel is attached prevent on the surface of static substrate, the support frame supports prevent on the other surface of static substrate, prevent that the static substrate comprises according to parts by weight by following raw materials: 46-60 parts of cement, 10-15 parts of stone powder, 5-10 parts of foaming agent, 5-10 parts of carbon powder, 3-5 parts of resistance reducing agent and 0.5-1 part of water reducing agent. The embodiment of the invention provides an anti-static floor, and an anti-static base material of the anti-static floor is improved, compared with the existing anti-static base material, the carbon powder is added in the scheme of the invention, and the addition of the carbon powder can improve the conductivity of the anti-static base material and further improve the anti-static performance of the anti-static floor.)

1. An antistatic floor, comprising: attached panel, prevent static substrate, support frame, attached panel is attached prevent on the surface of static substrate, the support frame supports prevent on the other surface of static substrate, prevent that the static substrate comprises according to parts by weight by following raw materials: 46-60 parts of cement, 10-15 parts of stone powder, 5-10 parts of foaming agent, 5-10 parts of carbon powder, 3-5 parts of resistance reducing agent and 0.5-1 part of water reducing agent.

2. The antistatic floor as claimed in claim 1, wherein the water reducing agent is any one or a mixture of any two or more of sodium hexametaphosphate, sodium tripolyphosphate and sodium metasilicate.

3. The antistatic floor as claimed in claim 1 or 2, further comprising: the device comprises a support column, a conductive insertion strip, a reinforcing beam and a support seat; a plurality of first through holes are formed in the attaching panel, a plurality of second through holes are formed in the anti-static substrate, and the first through holes and the second through holes are arranged in a one-to-one correspondence manner; the attaching panel is arranged on one surface of the anti-static substrate, the support frame is arranged on the other surface of the anti-static substrate, and the support seat is arranged at the corner of the support frame; the supporting seat is connected with the supporting column through a screw rod, a first threaded hole matched with the screw rod is formed in the bottom of the supporting seat, a second threaded hole matched with the screw rod is formed in the top of the supporting column, a first blind hole is formed in the bottom of the supporting seat, a second blind hole is formed in the top of the supporting column, and guide rods are arranged in the first blind hole and the second blind hole in a sliding mode; the rotary direction of the first threaded hole is opposite to that of the second threaded hole; a supporting plate is arranged at the bottom of the supporting column; the conductive embedded strip is embedded around the attached panel; the reinforcing beam is arranged on the bottom surface of the anti-static base material.

4. The antistatic floor as claimed in claim 3, wherein the attached panel is made of HPL or PVC.

5. The antistatic floor as claimed in claim 3, wherein a rotating portion is provided on a side wall of the screw.

6. The antistatic floor as claimed in claim 3, wherein the supporting base is welded to the supporting frame.

7. The antistatic floor as claimed in claim 3, wherein the total area of the first through holes is in the range of 17-44% of the area of the surface of the attached panel.

8. A method for producing an antistatic substrate, for producing the antistatic substrate as claimed in claim 1, comprising the steps of:

(1) dry mixing of raw materials: weighing 46-60 parts of cement, 10-15 parts of stone powder, 5-10 parts of foaming agent, 5-10 parts of carbon powder and 3-5 parts of resistance reducing agent, and dry-mixing the weighed raw materials in a mixer at 30-50 rpm for 5-10 minutes;

(2) dissolving a reagent: 0.5-1 part of water reducing agent is added with water and mixed evenly to prepare solution;

(3) mixing solid and liquid: adding the solution obtained in the step (2) into the stirrer, stirring and mixing the solution with the dry mixture obtained in the step (1), adjusting the rotating speed of the stirrer to 40-50 revolutions per minute, and stirring for 3-4 minutes according to GB/T9142-1988 technical Condition of concrete stirrer to obtain a slurry of the required antistatic base material;

(4) vibrating and exhausting: molding the slurry by casting, and vibrating and exhausting;

(5) standing the slurry: standing the uniform mixture;

(6) and (3) pressing and forming: and after standing, the mixed base material enters a hot stamping extruder through a spreading machine and a metering filling device, and is subjected to hot stamping under the pressure of 8-10MPa and at the temperature of 60-80 ℃ to prepare the antistatic base material.

9. The method for antistatic substrate according to claim 8, wherein the standing condition in the step (5) is: the temperature is 18-24 ℃, the humidity is 70-90%, and the standing time is 30-60 min.

Technical Field

The invention relates to the technical field of anti-static floors, in particular to an anti-static floor and a method for preparing an anti-static base material.

Background

The types of flooring currently on the market are classified according to the purpose: household, antistatic flooring, commercial, etc. Different from the household floor, the floor used in the industrial factory building generally requires the floor to have the characteristics of pressure resistance, seamless performance, wear resistance and the like so as to meet different industrial production environments. For precision electronics, computer rooms and the like, the ground is required to have the characteristics, and the ground also has the antistatic performance, wherein static electricity is one of the most difficult hazards to eliminate of the precision electronics and the computer rooms, so that random faults, operation errors or processing information errors can occur during the operation of a computer, and certain precision components can be possibly out of order or even damaged.

The domestic antistatic floor adopts a wooden floor, a PVC antistatic floor, antistatic paint brushing and the like. At present, the wood floor has larger output and sales volume, but has more defects, such as over-standard formaldehyde concentration, poor flame-retardant and waterproof performance, poor antistatic performance, poor impact resistance and the like. Meanwhile, other anti-static floors are poor in hardness and wear resistance, and some of the anti-static floors even cannot meet the existing experimental use requirements.

Most of the antistatic floors prepared by the prior art adopt antistatic paint, the antistatic floors can meet the use requirements by the method, but the price is higher, and industrial chemical reagents are mostly adopted, so that the problems of reagent dissolution and the like exist. Meanwhile, the floors used in the decoration field adopt clay and wall decoration materials using cement as a gelling agent, and although the floors have the advantages of high strength, good durability and the like, the floors have large capacity, poor antistatic, sound insulation and heat insulation properties, so that the application range of the floors is limited, and the stability of the floors and the uniformity of the distribution of the conductive performance are poor.

Disclosure of Invention

In order to solve the technical problems of poor stability of the floor and poor uniformity of conductivity distribution caused by poor antistatic, sound insulation and heat insulation performance and limited application range in the prior art, the invention provides an antistatic floor and a method for preparing an antistatic base material, and the specific technical scheme is as follows:

the embodiment of the invention provides an anti-static floor, which comprises: attached panel, prevent static substrate, support frame, attached panel is attached prevent on the surface of static substrate, the support frame supports prevent on the other surface of static substrate, prevent that the static substrate comprises according to parts by weight by following raw materials: 46-60 parts of cement, 10-15 parts of stone powder, 5-10 parts of foaming agent, 5-10 parts of carbon powder, 3-5 parts of resistance reducing agent and 0.5-1 part of water reducing agent.

Further, the water reducing agent is any one or a mixture of more than two of sodium hexametaphosphate, sodium tripolyphosphate and sodium metasilicate.

Further, the method also comprises the following steps: the device comprises a support column, a conductive insertion strip, a reinforcing beam and a support seat; a plurality of first through holes are formed in the attaching panel, a plurality of second through holes are formed in the anti-static substrate, and the first through holes and the second through holes are arranged in a one-to-one correspondence manner; the attaching panel is arranged on one surface of the anti-static substrate, the support frame is arranged on the other surface of the anti-static substrate, and the support seat is arranged at the corner of the support frame; the supporting seat is connected with the supporting column through a screw rod, a first threaded hole matched with the screw rod is formed in the bottom of the supporting seat, a second threaded hole matched with the screw rod is formed in the top of the supporting column, a first blind hole is formed in the bottom of the supporting seat, a second blind hole is formed in the top of the supporting column, and guide rods are arranged in the first blind hole and the second blind hole in a sliding mode; the rotary direction of the first threaded hole is opposite to that of the second threaded hole; a supporting plate is arranged at the bottom of the supporting column; the conductive embedded strip is embedded around the attached panel; the reinforcing beam is arranged on the bottom surface of the anti-static base material.

Furthermore, the material of the attached panel is HPL or PVC.

Furthermore, a rotating part is arranged on the side wall of the screw rod.

Further, the supporting seat is welded on the supporting frame.

Further, the total area of the first through holes accounts for 17% -44% of the area of the surface of the attached panel.

In a second aspect, an embodiment of the present invention provides a method for preparing an anti-static substrate, for preparing the anti-static substrate, including the following steps:

(1) dry mixing of raw materials: weighing 46-60 parts of cement, 10-15 parts of stone powder, 5-10 parts of foaming agent, 5-10 parts of carbon powder and 3-5 parts of resistance reducing agent, and dry-mixing the weighed raw materials in a mixer at 30-50 rpm for 5-10 minutes;

(2) dissolving a reagent: 0.5-1 part of water reducing agent is added with water and mixed evenly to prepare solution;

(3) mixing solid and liquid: adding the solution obtained in the step (2) into the stirrer, stirring and mixing the solution with the dry mixture obtained in the step (1), adjusting the rotating speed of the stirrer to 40-50 revolutions per minute, and stirring for 3-4 minutes according to GB/T9142-1988 technical Condition of concrete stirrer to obtain a slurry of the required antistatic base material;

(4) vibrating and exhausting: molding the slurry by casting, and vibrating and exhausting;

(5) standing the slurry: standing the uniform mixture;

(6) and (3) pressing and forming: and after standing, the mixed base material enters a hot stamping extruder through a spreading machine and a metering filling device, and is subjected to hot stamping under the pressure of 8-10MPa and at the temperature of 60-80 ℃ to prepare the antistatic base material.

Further, the standing conditions in the step (5) are as follows: the temperature is 18-24 ℃, the humidity is 70-90%, and the standing time is 30-60 min.

The embodiment of the invention provides an anti-static floor, which comprises: attached panel, prevent static substrate, support frame, attached panel is attached prevent on the surface of static substrate, the support frame supports prevent on the other surface of static substrate, prevent that the static substrate comprises according to parts by weight by following raw materials: 46-60 parts of cement, 10-15 parts of stone powder, 5-10 parts of foaming agent, 5-10 parts of carbon powder, 3-5 parts of resistance reducing agent and 0.5-1 part of water reducing agent. The embodiment of the invention provides an anti-static floor, and an anti-static base material of the anti-static floor is improved, compared with the existing anti-static base material, the carbon powder and the resistance reducing agent are added in the scheme of the invention, and the addition of the carbon powder can improve the conductivity of the anti-static base material and further improve the anti-static performance of the anti-static floor; according to the technical scheme, the added carbon powder and the resistance reducing agent are low in adding cost, and through test detection, the performance of the anti-static floor provided by the invention is improved by more than 50% compared with that of the existing anti-static floor.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.

Fig. 1 is a schematic structural view of an all-steel ventilation floor according to an embodiment of the present invention.

Fig. 2 is a schematic view of a partially disassembled structure of an all-steel ventilation floor according to an embodiment of the present invention.

Fig. 3 is a schematic view of an assembly structure of a supporting seat and a supporting pillar according to an embodiment of the present invention.

Fig. 4 is a schematic view of another assembly structure of a supporting seat and a supporting pillar according to an embodiment of the present invention.

Fig. 5 is a schematic view of a disassembled structure of a supporting seat and a supporting pillar according to an embodiment of the present invention.

Reference numerals:

the anti-static electricity-proof support comprises an attached panel 1, an anti-static substrate 2, a support frame 3, a support column 4, a conductive insertion strip 5, a reinforcing beam 6, a support seat 7, a first through hole 8, a second through hole 9, a screw rod 10, a first threaded hole 11, a second threaded hole 12, a first blind hole 13, a second blind hole 14, a guide rod 15, a support plate 16 and a rotating part 17.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all 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.

Example 1

Referring to fig. 1 to 5, an embodiment of the present invention provides an anti-static floor, including: attached panel 1, prevent static substrate 2, support frame 3, attached panel 1 is attached prevent that static substrate 2 is on one surface, support frame 3 supports prevent that another of static substrate 2 is on the surface, prevent that static substrate 2 comprises according to parts by weight by following raw materials: 46-60 parts of cement, 10-15 parts of stone powder, 5-10 parts of foaming agent, 5-10 parts of carbon powder, 3-5 parts of resistance reducing agent and 0.5-1 part of water reducing agent.

The embodiment of the invention provides an anti-static floor, which comprises: attached panel 1, prevent static substrate 2, support frame 3, attached panel 1 is attached prevent that static substrate 2 is on one surface, support frame 3 supports prevent that another of static substrate 2 is on the surface, prevent that static substrate 2 comprises according to parts by weight by following raw materials: 46-60 parts of cement, 10-15 parts of stone powder, 5-10 parts of foaming agent, 5-10 parts of carbon powder, 3-5 parts of resistance reducing agent and 0.5-1 part of water reducing agent. The embodiment of the invention provides an anti-static floor, and an anti-static base material 2 of the anti-static floor is improved, compared with the existing anti-static base material 2, the carbon powder and the resistance reducing agent are added in the scheme of the invention, the addition of the carbon powder can improve the conductivity of the anti-static base material 2, and further improve the anti-static performance of the anti-static floor, and on the basis, the resistance reducing agent is added, so that the prevention of the anti-static base material 2 can be further reduced, and further improve the anti-static performance of the anti-static floor; according to the technical scheme, the added carbon powder and the resistance reducing agent are low in adding cost, and through test detection, the performance of the anti-static floor provided by the invention is improved by more than 50% compared with that of the existing anti-static floor.

In a specific embodiment, the water reducing agent is any one or a mixture of any two or more of sodium hexametaphosphate, sodium tripolyphosphate and sodium metasilicate.

In a specific embodiment, the method further comprises the following steps: the device comprises a support column 4, a conductive insertion strip 5, a reinforcing beam 6 and a support seat 7; a plurality of first through holes 8 are formed in the attachment panel 1, a plurality of second through holes 9 are formed in the anti-static substrate 2, and the first through holes 8 and the second through holes 9 are arranged in a one-to-one correspondence manner; the attached panel 1 is arranged on one surface of the anti-static substrate 2, the support frame 3 is arranged on the other surface of the anti-static substrate 2, and the support seat 7 is arranged at the corner of the support frame 3; the supporting seat 7 is connected with the supporting column 4 through a screw rod 10, a first threaded hole 11 matched with the screw rod 10 is formed in the bottom of the supporting seat 7, a second threaded hole 12 matched with the screw rod 10 is formed in the top of the supporting column 4, a first blind hole 13 is formed in the bottom of the supporting seat 7, a second blind hole 14 is formed in the top of the supporting column 4, and a guide rod 15 is arranged in the first blind hole 13 and the second blind hole 14 in a sliding mode; the screwing direction of the first threaded hole 11 is opposite to that of the second threaded hole 12; a support plate 16 is arranged at the bottom of the support column 4; the conductive embedded strip 5 is embedded around the attached panel 1; the reinforcing beam 6 is provided on the bottom surface of the antistatic base material 2.

It should be noted that the attachment panel 1 may be a HPL or PVC punching press surface, and the antistatic substrate 2 provided by the embodiment of the present invention is adopted to improve the electrostatic conductivity; specifically, in the actual assembly process, two layers of steel plates, namely an upper steel plate and a lower steel plate, need to be selected, wherein the upper steel plate is a 0.6mm Bao steel SPCC hard steel plate; the lower steel plate is a 0.7mm Bao steel ST14 deep-level stretching steel plate; an anti-static base material 2 is filled between the upper steel plate and the lower steel plate to improve the structural rigidity; after that, the attachment panel 1 is adhered to the surface of the upper steel plate, and it can be understood that, in the present embodiment, the anti-static substrate 2 includes an upper steel plate, a lower steel plate, and an anti-static substrate 2 filled between the upper steel plate and the lower steel plate; a first through hole 8 and a second through hole 9 are respectively formed on the attachment panel 1 and the anti-static substrate 2, and when the anti-static substrate 2 is filled, the first through hole 8 and the second through hole 9 need to be prevented from being blocked; furthermore, the mode of fixing the support frame 3 on the lower plate surface of the antistatic substrate 2 can be welding, in the embodiment, the adopted welding mode is manual welding, the area of the support can be 3.3 square meters, and the number of the cross beams forming the support can be 5; assembling the cross beams by using screws to manufacture a bracket, and welding and connecting the connecting parts of the bracket in a welding manner; then, welding the supporting seat 7 at the four direct corners, and arranging the supporting pillar 4 matched with the supporting seat 7, in this embodiment, the supporting seat 7 and the supporting seat 7 are connected by using a screw rod 10, in the existing bearing mechanism, the screw rod 10 is a device commonly used in the field, specifically, a first threaded hole 11 is arranged on the supporting seat 7, a second threaded hole 12 is arranged on the supporting pillar 4, one end of the screw rod 10 is in threaded connection with the first threaded hole 11, and the other end is in threaded connection with the second threaded hole 12, in practical application, when the supporting seat 7 and the supporting pillar 4 are kept still, the distance between the two can be adjusted by rotating the screw rod 10, and further the ground clearance of the anti-static substrate 2 is adjusted, for more convenient use by a user, in this embodiment, a first blind hole 13 is arranged on the supporting seat 7, and a second blind hole 14 is arranged on the supporting pillar 4, guide rods 15 are arranged in the first blind holes 13 and the second blind holes 14 and used for limiting the rotation of the supporting seat 7 and the supporting column 4; so that the user can adjust the distance between the supporting column 4 and the supporting seat 7 more conveniently. Finally, in order to further ensure the strength and the bearing capacity of the scheme provided by the embodiment, reinforcing beams 6 are crosswise arranged on the bottom surface of the anti-static base material 2; to improve the strength of the antistatic backing material 2.

It should be noted that the all-steel ventilation floor provided by the embodiment is suitable for various computer rooms, network communication rooms, monitoring and commanding centers, electronic factory clean rooms, clean rooms and the like, and occasions with antistatic and ventilation requirements. The device is used in places such as various data center machine rooms with lower air supply devices and the like in clean environments such as high-grade clean workshops, dust-free rooms, semiconductors, microelectronic chips, communication equipment, biochemical factories and the like, and in places such as dust prevention, static prevention, pipeline laying and the like.

By adopting the all-steel ventilation floor provided by the invention, the first through holes 8 and the second through holes 9 are correspondingly arranged on the anti-static base material 2 and the attachment panel 1 one by one, and the cavity is formed between the anti-static base material 2 and the bottom end of the supporting column 4, so that ventilation is more convenient. The scheme can effectively prevent static electricity, prevent fire and dust accumulation and can be flexibly exchanged; the full-manual welding has strong mechanical property, strong bearing capacity and good impact resistance; besides the functions of the common antistatic floor, the floor also has a ventilation function; the ventilation rate can be selected from 17-44%, and the requirements of various levels of purification environments are met; and an all-steel combined structure is adopted, so that the strength is high and the impact resistance is strong.

In one embodiment, the material of the attached panel 1 is HPL or PVC.

In one embodiment, a rotating portion 17 is provided on a side wall of the screw 10.

In one embodiment, the support base 7 is welded to the support frame 3.

In a specific embodiment, the total area of the first through holes 8 accounts for 17% -44% of the area of the plate surface of the attached panel 1.

In a second aspect, an embodiment of the present invention provides a method for preparing an anti-static substrate 2, for preparing the anti-static substrate 2, where the method includes the following steps:

(1) dry mixing of raw materials: weighing 46-60 parts of cement, 10-15 parts of stone powder, 5-10 parts of foaming agent, 5-10 parts of carbon powder and 3-5 parts of resistance reducing agent, and dry-mixing the weighed raw materials in a mixer at 30-50 rpm for 5-10 minutes;

(2) dissolving a reagent: 0.5-1 part of water reducing agent is added with water and mixed evenly to prepare solution;

(3) mixing solid and liquid: adding the solution obtained in the step (2) into the stirrer, stirring and mixing the solution with the dry mixture obtained in the step (1), adjusting the rotating speed of the stirrer to 40-50 revolutions per minute, and stirring for 3-4 minutes according to GB/T9142-1988 technical Condition of concrete stirrer to obtain the required slurry of the antistatic base material 2;

(4) vibrating and exhausting: molding the slurry by casting, and vibrating and exhausting;

(5) standing the slurry: standing the uniform mixture;

(6) and (3) pressing and forming: and after standing, the mixed base material enters a hot stamping extruder through a spreading machine and a metering filling device, and is subjected to hot stamping under the pressure of 8-10MPa and at the temperature of 60-80 ℃ to prepare the antistatic base material 2.

In one embodiment, the standing condition in the step (5) is: the temperature is 18-24 ℃, the humidity is 70-90%, and the standing time is 30-60 min.

Test examples

By using the preparation method of the antistatic base material 2 provided by the embodiment of the invention, the antistatic base material 2 is prepared, and the antistatic plate is prepared by using the antistatic base material 2, so that the antistatic plate 1 is obtained.

According to the prior art, foamed cement is prepared by adopting cement, stone powder and a foaming agent, an anti-static base material 2 is prepared, and the anti-static plate is prepared by utilizing the anti-static base material 2, so that the anti-static plate 2 is obtained.

Comparing the conductivity of the antistatic plate 1 and the antistatic plate 2, the resistance of the antistatic plate 1 is 0.5 x 10^-6Ohmic, resistance of the antistatic plate 2 is 1 x 10^-6Ohm, the limit load of the antistatic plate 1 is 13893N; the limit load of the antistatic plate 2 is 12450N; in conclusion, the antistatic base material 2 provided by the invention has good conductivity and good bearing capacity.

The embodiment of the invention provides an anti-static floor, which comprises: attached panel 1, prevent static substrate 2, support frame 3, attached panel 1 is attached prevent that static substrate 2 is on one surface, support frame 3 supports prevent that another of static substrate 2 is on the surface, prevent that static substrate 2 comprises according to parts by weight by following raw materials: 46-60 parts of cement, 10-15 parts of stone powder, 5-10 parts of foaming agent, 5-10 parts of carbon powder, 3-5 parts of resistance reducing agent and 0.5-1 part of water reducing agent. The embodiment of the invention provides an anti-static floor, and an anti-static base material 2 of the anti-static floor is improved, compared with the existing anti-static base material 2, the carbon powder and the resistance reducing agent are added in the scheme of the invention, the addition of the carbon powder can improve the conductivity of the anti-static base material 2, and further improve the anti-static performance of the anti-static floor, and on the basis, the resistance reducing agent is added, so that the prevention of the anti-static base material 2 can be further reduced, and further improve the anti-static performance of the anti-static floor; according to the technical scheme, the added carbon powder and the resistance reducing agent are low in adding cost, and through test detection, the performance of the anti-static floor provided by the invention is improved by more than 50% compared with that of the existing anti-static floor.

In this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

All the embodiments in the present specification are described in a related manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.