Patent Publication Number: US-9885527-B2

Title: Manifold assembly and heat exchanger having manifold assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a National Stage of International Patent Application No. PCT/CN2014/070745 filed on Jan. 16, 2014, which claims priority to and all the benefits of Chinese Patent Application No. 201310327178.2 filed on Jul. 30, 2013, and Chinese Patent Application No. 201310430058.5 filed on Sep. 18, 2013, all of which are hereby expressly incorporated herein by reference in their entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of heat exchanging, particularly to a header assembly and a heat exchanger including the header assembly. 
     2. Description of the Related Art 
     The heat exchanger, such as a micro-channel heat exchanger, in the related art needs to distribute a refrigerant when used as an evaporator in order to improve the uniformity and effect of heat exchanging. Typically, a distributing tube of a built-in type is inserted into the header from an end of the header. The distributing tube has a plurality of openings through which the refrigerant may flow into the header. 
     However, the shape and position of the openings of the distributing tube in the related art are fixed. When operating conditions of the heat exchanger is changed, the distribution of the refrigerant cannot be regulated, so that the uniformity and performance of heat exchanging are reduced. Therefore, there is a need to improve the heat exchanger. 
     SUMMARY OF THE INVENTION 
     Embodiments of the present disclosure seek to solve at least one of the problems existing in the related art to at least some extent. Therefore an object of the present disclosure is to provide a header assembly which may adjust the distribution of the refrigerant as desired and may improve the distributing effect of the refrigerant. 
     Another object of the present disclosure is to provide a heat exchanger including the header assembly. 
     The present invention is directed toward a header assembly including: a header; a distribution member disposed within the header and having at least one distribution opening; a regulating member disposed movably at the distribution member and configured to regulate the distributing opening; and a driving member configured to magnetically drive the regulating member to move so as to regulate the distribution opening. 
     With the header assembly according to embodiments of the present invention, by changing the position of the driving member, the position of the regulating member may be changed via magnetic force. In this way, the distribution opening may be regulated, thus regulating the distribution of the refrigerant. Therefore the refrigerant distribution may be regulated conveniently according to specific application requirements, which may satisfy different operations conditions. In addition, both the effect of refrigerant distribution and the applicability of the header assembly may be improved. 
     In some embodiments, the driving member may be disposed externally of the header. In some embodiments, the driving member may be disposed on an outer wall of the header, and a position of the driving member may be adjustable. 
     In some embodiments, at least one of the regulating member and the driving member may be a permanent magnet. In some embodiments, one of the regulating member and the driving member may be a permanent magnet, and the other may be capable of interacting with the permanent magnet via magnetic force. In some embodiments, the other of the regulating member and the driving member may be a steel part. In some embodiments, the regulating member may be movable along an axis direction of the header, and a position of the driving member may be adjustable along the axial direction of the header. 
     In some embodiments, a protrusion may be disposed on an outer wall of the header, at least one groove may be formed in the protrusion and configured to receive the driving member, and the position of the driving member may be adjustable along the axial direction of the header. 
     In some embodiments, one groove may be formed in the protrusion and extended along the axial direction of the header, and the driving member may be slidably disposed in the one groove. In some embodiments, a plurality of grooves may be formed in the protrusion and spaced apart from each other along the axial direction of the header, and the driving member is adapted to be selectively disposed in any of the plurality of grooves. 
     In some embodiments, the distribution member may include a plurality of distribution openings, the header assembly may include a plurality of regulating members and a plurality of driving members, and the plurality of distribution openings may be in one-to-one correspondence with the plurality of regulating members, and with the plurality of driving members, respectively. 
     In some embodiments, the distribution member may include a sliding groove formed at a position corresponding to the plurality of the distribution openings, and the regulating member may be fitted in the sliding groove and movable along the axial direction of the header. 
     In some embodiments, the distribution opening is configured as an elongated groove extended along the axial direction of the header, the header assembly may include a plurality of regulating members and a plurality of driving members in one-to-one correspondence with the plurality of regulating members, and the plurality of regulating members may be spaced apart from each other in the axial direction of the header. 
     In some embodiments, the distribution member is configured as a distributing tube, the distribution opening is configured as an elongated groove extended along a circumferential direction of the distributing tube, the regulating member may be disposed on a wall of the distributing tube and movable along the circumferential direction of the distributing tube, and the driving member may be disposed on an outer wall of the header and a position of the driving member may be adjustable along a circumferential direction of the header. 
     In some embodiments, a protrusion is disposed on an outer wall of the header and at least one groove is formed in the protrusion, the driving member may be disposed in the groove and the position of the driving member may be adjustable along the circumferential direction of the header. 
     In some embodiments, a plurality of grooves may be formed in the protrusion, and the driving member is adapted to be selectively disposed in any of the plurality of grooves. In some embodiments, one groove is formed in the protrusion and extended along the circumferential direction of the header, and the driving member may be disposed in the groove and slidable along the circumferential direction of the header. 
     In some embodiments, a plurality of distribution openings may be formed in the distribution member and spaced apart in the axial direction of the distributing tube. A plurality of protrusions may be disposed on the header, spaced apart along the axial direction of the header and in one-to-one correspondence with the plurality of distribution openings. The header assembly may include a plurality of driving members and a plurality of regulating members, and the plurality of driving members may be in one-to-one correspondence with the plurality of regulating members, with the plurality of distribution openings, and with the plurality of protrusions, respectively. 
     In some embodiments, the distribution member is configured as a distributing tube, the distribution opening is configured as an elongated groove extended along a spiral direction of the distributing tube, the regulating member may be disposed on a wall of the distributing tube and movable along the spiral direction, and the driving member may be disposed on an outer wall of the header and a position of the driving member may be adjustable along the spiral direction. 
     In some embodiments, the driving member may be disposed within the header, the regulating member may be a permanent magnet or a member capable of interacting with the permanent magnet via magnetic force, and the driving member may include a plurality of electromagnets disposed along an circumferential direction or an axial direction of the header and spaced apart from each other. In some embodiments, the driving member may be disposed on an inner wall of the header. 
     In some embodiments, the driving member may be disposed externally of the header, the regulating member may be a permanent magnet or a member capable of interacting with the permanent magnet via magnetic force, and the driving member may include a plurality of electromagnets disposed along a circumferential direction or an axial direction of the header and spaced apart from each other. In some embodiments, the driving member may be disposed on an outer wall of the header. 
     In some embodiments, the header assembly may include a plurality of driving members and a plurality of regulating members in one-to-one correspondence with the plurality of driving members. 
     In some embodiments, the distribution opening is configured as an elongated groove extended along an axial direction of the distribution member, the header assembly may include a plurality of regulating members and a plurality of driving members in one-to-one correspondence with the plurality of regulating members, and the plurality of regulating members may be spaced apart from each other in the axial direction of the distribution member. 
     Embodiments of the present disclosure provide a heat exchanger including: a first header assembly and a second header assembly, at least one of the first and second header assemblies being the above-mentioned header assembly according to embodiments of the present disclosure; a tubes each defining a first end connected with a first header of the first header assembly, and a second end connected with a second header of the second header assembly; and fins disposed between adjacent tubes. 
     Other objects, features and advantages of the present invention will be readily appreciated as the same becomes better understood after reading the subsequent description taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other advantages of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG. 1  is a schematic view of a distributing tube of a header assembly according to an embodiment of the present disclosure; 
         FIG. 2  is a schematic view of a header of a header assembly according to an embodiment of the present disclosure; 
         FIG. 3  is a schematic view of a header assembly according to an embodiment of the present disclosure, in which a tube is shown; 
         FIG. 4  is a schematic view of a distributing tube of a header assembly according to another embodiment of the present disclosure; 
         FIG. 5  is a schematic view of a header of a header assembly according to another embodiment of the present disclosure; 
         FIG. 6  is a schematic view of a header assembly according to another embodiment of the present disclosure, in which a tube is shown; 
         FIG. 7  is a schematic view of a distributing tube of a header assembly according to a further embodiment of the present disclosure; 
         FIG. 8  is a schematic view of a header of a header assembly according to a further embodiment of the present disclosure; 
         FIG. 9  is a schematic view of a header assembly according to a further embodiment of the present disclosure, in which a tube is shown; 
         FIG. 10  is a schematic view of a header assembly according to a still further embodiment of the present disclosure; 
         FIG. 11  is a schematic view of a header assembly according to yet still further embodiment of the present disclosure; 
         FIG. 12  is a schematic view of a heat exchanger according to an embodiment of the present disclosure; and 
         FIG. 13  is a partial enlarged view of a heat exchanger according to an embodiment of the present disclosure. 
     
    
    
     REFERENCE NUMERALS IN THE DRAWINGS 
       100 : header;  100 A: first header;  100 B: second header;  200 : tube;  300 : fin;  400 : distributing tube;  401 : distribution opening;  402 : sliding groove;  500 : regulating member;  600 : driving member;  700 : protrusion;  701 : groove;  800 : controller;  900 : power source. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to embodiments of the present disclosure. The embodiments described herein with reference to drawings are explanatory, illustrative, and used to generally understand the present disclosure. The embodiments shall not be construed to limit the present disclosure. The same or similar elements and the elements having same or similar functions are denoted by like reference numerals throughout the descriptions. 
     The header assembly according to embodiments of the present disclosure will be described below with reference to the drawings. As shown in  FIGS. 1-13 , the header assembly according to embodiments of the present disclosure may include a header  100 , a distribution member, a regulating member  500  and a driving member  600 . 
     The distribution member is disposed within the header  100 . The distribution member has at least one distribution opening  401  for distributing refrigerant into the header  100 . The regulating member  500  is movably disposed on the distribution member to regulate the distribution opening  401 . The driving member  600  is used to drive the regulating member  500  via magnetic force to moves so as to regulate the distribution opening  401 . 
     It shall be appreciated that, the phase “regulate the distribution opening” shall be understood broadly herein in the present disclosure. For example, the phase “regulate the distribution opening” may include adjusting the opening degree of the distribution opening, the position of the distribution opening, the opening direction of the distribution opening or the opening angle of distribution opening. In other words, as far as the movement of the regulating apart results in changing of at least one selected from the group consisting of the amount of refrigerant ejected by the distribution opening, the position where the refrigerant are ejected, the ejecting direction of the refrigerant and the ejecting angle of the refrigerant, it should be appreciated that the distribution opening is regulated. 
     With the header assembly according to embodiments of the present disclosure, by changing the position of the driving member  600 , the position of the regulating member  500  may be changed via magnetic force, and the distribution opening  401  may be regulated. Therefore the distribution of the refrigerant may be adjusted. In this way, the distribution of the refrigerant may be adjusted conveniently as desired, and requirements for different operation conditions may be satisfied, thereby both the applicability and distributing effect of the refrigerant may be improved. 
     As shown in  FIGS. 1-10 , in some embodiments, the driving member  600  may be disposed externally of the header  100 . Preferably, the driving member  600  may be disposed on an outer wall of the header  100  and the position of the driving member  600  may be adjustable, thus facilitating the assembling and movement of the driving member  600 . 
     It shall be appreciated that, the expression “the position of the driving member  600  may be adjustable” shall be understood broadly herein and includes that the driving member  600  may change its position continuously, and that the driving member  600  may be disposed at different positions. In other words, “the position of the driving member  600  may be adjustable” means that the position of the driving member  600  is changeable. 
     It shall be appreciated that, the driving member  600  may be disposed at a position other than on the outer wall of the header  100 , as far as the distribution opening  401  can be regulated by moving the driving member  600  so as to change the position of the regulating member  500 . For example, the driving member  600  may be mounted externally of the header  100  and on a separate support (not shown) which is disposed adjacent to the header  100 . 
     In some embodiments, at least one of the regulating member  500  and the driving member  600  may be configured as a permanent magnet. For example, one of the regulating member  500  and the driving member  600  is a permanent magnet, and the other of the regulating member  500  and the driving member  600  is capable of interacting with the permanent magnet via magnetic force. In an embodiment, the other of the regulating member  500  and the driving member  600  may be configured a steel part. Alternatively, the other of the regulating member  500  and the driving member  600  may be made from other materials. In some embodiments, the regulating member  500  is a permanent magnet, and the driving member  600  is a steel part. Alternatively, the driving member  600  is a permanent magnet, and the regulating member  500  is a steel part. Further alternatively, both the regulating member  500  and the driving member  600  are electromagnets. In an embodiment, the regulating member  500  and the driving member  600  are interacted via magnetic force. 
     In some embodiments, the distribution member may be configured as a distributing tube  400 . The distributing tube  400  may be a circular tube. Alternatively, the cross-section of the distributing tube  400  may have other shapes such as a rectangle and so on. 
     For the convenience of description, in the following description, the distribution member is embodied as a distributing tube  400  having a circular cross-section, the regulating member  500  is a steel part, and the driving member  600  is a permanent magnet. It shall be appreciated that this is explanary and should not be construed as limitation to the present disclosure. 
     In some embodiments, the regulating member  500  may be movable in an axis direction of the header  100 , and the position of the driving member  600  may be adjustable in the axial direction of the header  100 . 
     As shown in  FIGS. 1-3 , distributing tube  400  has a plurality of distribution openings  401  spaced apart from each other in an axial direction (left-right direction in  FIG. 1 , i.e. the axial direction of the header  100 ) of the distributing tube  400 . Specifically, the plurality of distribution openings  401  may be distributed linearly. It is appreciated that, the plurality of distribution openings  401  may be distributed spirally along the axial direction of the distributing tube  400 . Alternatively, the plurality of distribution openings  401  may be distributed in any other suitable manners. 
     Accordingly, one regulating member  500  may be disposed at each distribution opening  401 . A sliding groove  402  may be formed in a side wall of the distribution opening  401 , and by means of sliding the regulating member  500  along the axial direction of the distributing tube  400 , the distribution opening  401  may be regulated. In some embodiments, a plurality of driving members  600  (such as permanent magnet) may be disposed on an outer wall of the header  100 . The expression “position of the driving member  600  is adjustable” means the position of the driving member  600  with regard to the header  100  is changeable. For example, the driving member  600  may be slidable with regard to the header  100 , or the driving member  600  may be fixed at different positions with regard to the header  100 . In some embodiments, the plurality of driving members  600  may be in one-to-one correspondence with the plurality of regulating members  500 . When the position of one driving member  600  is changed, the regulating member  500  corresponding to the one driving member  600  may be moved with regard to the distributing tube  400 , thus the distribution opening  401  is regulated. 
     In some embodiments, as shown in  FIGS. 1-3 , a plurality of protrusions  700  are disposed or formed on an outer wall of the header  100  and in one-to-one correspondence with the plurality of distribution openings  401 . The protrusion  700  may include a plurality of grooves  701  formed therein and spaced apart from each other in the axial direction of the header  100 . The driving member  600  is adapted to be selectively disposed in any of the plurality of grooves  701 . It is appreciated that, the term “selectively dispose” should be understood broadly, i.e. the driving member  600  may be mounted or positioned in any of the plurality of grooves  701 . When the driving member  600  is moved from one groove  701  to another groove  701 , the position of the driving member  600  is changed, thus driving the regulating member  500  to move and thereby regulating the distribution opening  401 . 
     In some embodiments, the protrusion  700  may be mounted on an outer wall of the header  100  via welding. Alternatively, the protrusion  700  may be fixed to the outer wall of the header  100  via a fixing element such as a clipping element. The driving member  600  may be fixed in the groove  701  via magnetic force. If the protrusion  700  is made from non-metallic material, the driving member  600  may be selectively disposed in the groove  701  in other manners, for example, the driving member  600  may be selectively disposed in the groove  701  via a snap fit. 
     In some embodiments, one groove  701  may be formed in the protrusion  700  and extended along the axial direction of the header  100 . The driving member  600  may be disposed in the groove  701 , and slidable in the axial direction of the header  100  so as to change the position thereof. 
     In some embodiments, as shown in  FIGS. 4-6 , the distribution opening  401  is formed as an elongated groove extended along the axial direction of the distributing tube  400 . The header assembly may include a plurality of regulating members  500  and a plurality of driving members  600  in one-to-one correspondence with the plurality of regulating members  500 . The plurality of regulating members  500  are spaced apart from each other in the axial direction of the distributing tube  400 . Alternatively, the elongated groove may be extended spirally about the axial of the distributing tube  400 , i.e. along a spiral direction. In such cases, the position of the driving member  600  may be adjustable along the spiral direction. In this way, the regulating member  500  may be driven to move along the spiral direction, thus regulating the distribution opening  401 . 
     In some embodiments, a sliding groove  402  may be formed in a side wall of the elongated groove, and the corresponding side of each regulating member  500  is fitted in the sliding groove  402 . As shown in  FIGS. 1-3 , in some embodiments, a plurality of protrusions  700  are disposed on the outer wall of the header  100 , a plurality of grooves  701  may be formed in each protrusion  700 , and the driving member  600  is adapted to be selectively disposed in any of the plurality of grooves  701 . Alternatively, one protrusion  700  is formed on the outer wall of the header  100  and extended along the axial direction of the header  100 . A plurality of grooves  701  spaced apart from each other in the axial direction of the header  100 , or one groove  701  extended along the axial direction of the header  100  may be formed in the one protrusion  700 . 
     Other structures and operations shown in embodiments shown in  FIGS. 4-6  are substantially the same as those in  FIGS. 1-3 , thus details related thereof are omitted herein. 
     As shown in  FIGS. 7-9 , in some embodiments, a plurality of distribution openings  401  are provided, each distribution openings  401  is formed as an elongated groove extended along a circumferential direction of the distributing tube  400 . The header assembly includes a plurality of regulating members  500  and a plurality of driving members  600 , and the plurality of distribution openings  401  are in one-to-one correspondence with the plurality of regulating members  500 , and with the plurality of driving members  600 , respectively. The regulating member  500  may be slidable in the circumferential direction of the distributing tube  400 . For example, a sliding groove  402  may be formed in a side wall of the elongated groove, and the corresponding side of the regulating member  500  is moveably fitted in in the sliding groove  402 . The driving member  600  may be disposed on an outer wall of the header  100 , and the position of the driving member  600  may be adjustable in the circumferential direction of the header  100 . 
     In some embodiments, a protrusion  700  may be formed on the outer wall of the header. A groove  701  may be formed in the protrusion  700 , and the driving member  600  may be disposed in the groove  701  and the position of the driving member  600  may be adjustable in the circumferential direction of the header  100 . 
     Alternatively, a plurality of grooves  701  may be formed in the protrusion  700 , and the driving member  600  is adapted to be selectively disposed in any of the plurality of grooves  701 . In other words, the driving member  600  may be positioned or mounted in any of the plurality of grooves  701 . Further alternatively, one groove  701  extended along the circumferential direction of the header  100  may be formed in the protrusion  700 , and the driving member  600  may be disposed in the one groove  701  and slidable in the circumferential direction of the header  100 . 
     In some embodiments, as shown in  FIGS. 8-9 , there are a plurality of distribution openings  401  spaced apart in the axial direction of the distributing tube  400 . A plurality of protrusions  700  spaced apart along the axial direction of the header  100  may be formed on the outer wall of the header  100 , and each of the plurality of protrusions  700  may be extended along the circumferential direction of the header  100 . A plurality of grooves  701  spaced apart along the circumferential direction of the header  100  may be formed in each of the plurality of protrusions  700 . The groove  701  is configured to receive the driving member  600 , and the driving member  600  is adapted to be selectively disposed in any of the plurality of grooves  701 . Then the position of the driving member  600  may be changed so as to drive the regulating member  500  to move and to regulate the distribution opening  401 . Alternatively, one groove  701  may be formed in each of the plurality of protrusions  700 , and the driving member  600  is adapted to be selectively disposed in the one groove  701  and is slidable in the one groove  701 . 
     It is appreciated that, the protrusion  700  corresponding to each distribution opening  401  may be extended along the circumferential direction of the header  100  and be integrally formed as a single piece. Alternatively, the protrusion  700  may include a plurality of sub-protrusions spaced apart from each other in the circumferential direction of the header  100 . 
     In some embodiments, the distribution opening  401  configured as the elongated groove may extend spirally about the axis of the distributing tube  400  (i.e. along a spiral direction), and the position of the regulating member  500  is adjustable in the spiral direction. In this way, the regulating member  500  may be driven to move in the spiral direction, thus regulating the distribution opening  401 . 
     By means of disposing the driving member  600  on the outer wall of the header  100 , the regulating member  500  positioned in the header  100  may be driven to move the regulating member  500 , thus regulating the distribution opening  401 . The header assembly according to embodiments of the present disclosure may be applied in different applications and the refrigerant distribution effect is improved. 
     As shown in  FIG. 11 , in some embodiments, the driving member  600  may be disposed within the header  100 , for example, on an inner wall of the header  100 . The regulating member  500  may be a permanent magnet or a member capable of interacting with the permanent magnet via magnetic force, for instance, the regulating member  500  may be a steel part. In some embodiments, the driving member  600  includes a plurality of electromagnets disposed along the circumferential direction or the axial direction of the header  100  and spaced apart from each other. 
     A plurality of driving members  600  each of which is in the form of electromagnet may be connected to a power source  900  and a controller  800  via wires. The controller  800  is configured to control the plurality of electromagnets to selectively connect with the power source  900 . Then the electromagnets which are connected with the power source  900  may generate magnetic force. By means of changing the electromagnets which are connected with the power source  900 , the position where the magnetic force is generated may be changed, thus driving the regulating member  500  to move and thereby to regulate the regulating the distribution opening  401 . 
     In some embodiments, as shown in  FIG. 10 , the driving member  600  may be disposed externally of the header  100 , for example, on the outer wall of the header  100 . The regulating member  500  may be a permanent magnet or a member capable of interacting with the permanent magnet via magnetic force. The driving member  600  may include a plurality of electromagnets disposed along the circumferential direction or the axial direction of the header  100  and spaced apart from each other. 
     Similar to the embodiment shown in  FIG. 11 , a plurality of driving members  600  each of which is in the form of electromagnet may be connected to a power source  900  and a controller  800  via wires. The controller  800  is configured to control the plurality of electromagnets to selectively connect with the power source  900 . Then the electromagnets which are connected with the power source  900  may generate magnetic force. By means of changing the electromagnets which are connected with the power source  900 , the position where the magnetic force is generated may be changed, thus driving the regulating member  500  to move and thereby to regulate the distribution opening  401 . 
     Similar to the embodiments shown in  FIGS. 10 and 11 , the distribution member may include a plurality of distribution openings  401  and the header assembly may include a plurality of regulating members  500  in one-to-one correspondence with the plurality of driving members  600 . Alternatively, the distribution opening  401  is configured as an elongated groove extended along the axial direction of the distributing tube  400 . The header assembly may include a plurality of regulating members  500  and a plurality of driving members  600  in one-to-one correspondence with the plurality of regulating members  500 . The plurality of regulating members  500  may be spaced apart from each other in the axial direction of the distributing tube  400 . 
     In some embodiments, it is appreciated that, the regulating member  500  may be movable along both the circumferential and axial directions of the distributing tube  400 . Accordingly, the position of the driving member  600  along both the circumferential and axial directions of the distributing tube  400  may be adjustable. 
     A heat exchanger according to embodiments of the present disclosure will be discussed with reference to  FIGS. 12 and 13 . As shown in  FIGS. 12 and 13 , the heat exchanger according to embodiments of the present disclosure may include a first header assembly, a second header assembly, tubes  200  and fins  300  disposed between adjacent tubes  200 . As shown in  FIGS. 12 and 13 , only a part of fins  300  are shown for the sake of simplification. 
     At least one of the first and second header assemblies is the header assembly described with reference to the above to embodiments of the present disclosure. Two ends of the tube  200  are connected with the first and second header assemblies respectively, so that a first header  100 A of the first header assembly is communicated with a second header  100 B of the second header assembly. In other words, the tube  200  defines a first end connected with a first header  100 A of the first header assembly, and a second end connected with a second header  100 B of the second header assembly. 
     In some embodiments, the heat exchanger may be a micro-channel heat exchanger. 
     In some embodiments, the tube  200  may be a flat tube. 
     By means of changing the position of the driving member, the driving member may drive the regulating member via magnetic force, so that the regulating member moves to regulate the distribution opening. Then the heat exchanger according to embodiments of the present disclosure may be applied in different operation conditions and applications, which improves the applicability and distribution effect of the refrigerant. In addition, the heat exchanging effect may also be improved. 
     In the specification, it should be understood that, the terms such as “central”, “longitudinal”, “lateral”, “width”, “thickness”, “above”, “below”, “front”, “rear”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “clockwise”, “counter-clockwise” should be construed to refer to the orientation as then described or as shown in the drawings. These terms are merely for convenience and concision of description and do not alone indicate or imply that the device or element referred to must have a particular orientation. Thus, it cannot be understood to limit the present disclosure. 
     In addition, terms such as “first” and “second” are used herein for purposes of description and are not intended to indicate or imply relative importance or significance or impliedly indicate quantity of the technical feature referred to. Thus, the feature defined with “first” and “second” may comprise one or more this feature. In the description of the present disclosure, “a plurality” of means including two or more than two this features, unless specified otherwise. 
     In the present invention, unless specified or limited otherwise, the terms “mounted,” “connected,” “coupled,” “fixed” and the like are used broadly, and may be, for example, fixed connections, detachable connections, or integral connections; may also be mechanical or electrical connections; may also be direct connections or indirect connections via intervening structures; may also be inner communications of two elements, which can be understood by those skilled in the art according to specific situations. 
     In the present invention, unless specified or limited otherwise, a structure in which a first feature is “on” or “below” a second feature may include an embodiment in which the first feature is in direct contact with the second feature, and may also include an embodiment in which the first feature and the second feature are not in direct contact with each other, but are contacted via an additional feature formed therebetween. Furthermore, a first feature “on,” “above,” or “on top of” a second feature may include an embodiment in which the first feature is right or obliquely “on,” “above,” or “on top of” the second feature, or just means that the first feature is at a height higher than that of the second feature; while a first feature “below,” “under,” or “on bottom of” a second feature may include an embodiment in which the first feature is right or obliquely “below,” “under,” or “on bottom of” the second feature, or just means that the first feature is at a height lower than that of the second feature. 
     Reference throughout this specification to “an embodiment,” “some embodiments,” “one embodiment”, “another example,” “an example,” “a specific example,” or “some examples,” means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. Thus, the appearances of the phrases such as “in some embodiments,” “in one embodiment”, “in an embodiment”, “in another example,” “in an example,” “in a specific example,” or “in some examples,” in various places throughout this specification are not necessarily referring to the same embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples. 
     Although explanatory embodiments have been shown and described, it would be appreciated by those skilled in the art that the above embodiments cannot be construed to limit the present disclosure, and changes, alternatives, and modifications can be made in the embodiments without departing from spirit, principles and scope of the present disclosure. 
     The invention has been described in an illustrative manner. It is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described.