WASHING MACHINE INNER DRUM AND WASHING MACHINE HAVING SAME

Abstract

The invention relates to washing machines, and more particularly, to a washing machine inner drum and a washing machine having the same. The inner drum has a drum wall provided with a plurality of pressed structures and a plurality of dehydration holes. The pressed structures includes protrusions pointing to an inside of the inner drum. A bottom of each protrusion is of a parallelogram, and the protrusions are arranged in rows and columns; gaps between protrusions in adjacent columns and adjacent rows form straight flow channels for water flows to pass, and the dehydration holes are arranged in the straight flow channels.

Description

FIELD OF THE INVENTION

[0001] The present invention relates generally to washing machines, and more particularly, to a washing machine inner drum and a washing machine having the same.

BACKGROUND OF THE INVENTION

[0002] A drum wall of an inner drum of conventional washing machines is either provided with many vertical pressed ribs, where multiple neatly arranged drainage holes are provided between these vertical pressed ribs, and these vertical pressed ribs strengthen a vertical direction of the drum wall, but do not strengthen a circumferential direction; or provided with inclined pressed ribs, where the inclined pressed ribs strengthen the drum wall along a direction in which the pressed ribs cline, but do not strengthen the wall along a direction perpendicular to the pressed ribs. In addition, in the conventional washing machines, the pressed ribs disposed on the inner drum are of a single shape, and are commonly circular or elliptical, so that pressed ribs on an inner surface of the inner drum are not transited through edges and corners, which reduces wear on clothes when the washing machine are at work.

[0003] Chinese Patent Application No. CN201020186528.X discloses a washing machine inner drum, including an inner drum body whose drum wall has a plurality of opening holes, a gimbal fixed to an upper part of the inner drum body, and an inner drum bottom fixed to a lower part of the inner drum body, where each opening hole is formed by inclining and flanging from inside to outside, and has a small outer end and a large inner end. The drum wall of the inner drum body has a plurality of externally compressed annular protruding areas in a circumferential direction, and the opening holes are uniformly distributed in the middle of the annular protruding areas. In this washing machine inner drum, indentations are neatly arranged in the circumferential direction in the column, and transverse indentations in the circumferential direction achieve a single strengthening effect on the drum wall of the inner drum, and do not strengthen the inner drum in a vertical direction. In addition, drainage holes are also neatly arranged in the circumferential direction. Therefore, there exist some annular areas that cannot be flushed on an inner wall of an outer drum, causing the inner drum not to be thoroughly cleaned.

[0004] For another example, Chinese Patent No. CN1608157A discloses an inner drum having a domed structure directed to the inside of the inner drum, where the inner drum is rotatably supported in an enclosure of a washing processing machine, and has at least one bottom plate and a shell, which are partially formed by sheets. Either one or both of the bottom plate and the shell is provided with the domed structure directed to the inside of inner drum. The domed structure includes a protrusion directed to the inside of the inner drum, and an edge of the protrusion is basically circular or elliptical or oval. In this application, strength in a center line of each row of protrusions is relatively strong, but strength of a connection of every two adjacent rows of protrusions is relatively poor.

[0005] Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.

SUMMARY OF THE INVENTION

[0006] One of the objectives of the present invention is to provide a washing machine inner drum having pressed structures, which improves an appearance of a drum wall, and increases strength of the drum wall, so as to address the aforementioned deficiencies and inadequacies.

[0007] To achieve the objective of the present invention, the following technical solutions are adopted:

[0008] In one aspect of the invention, a washing machine inner drum is provided to have a drum wall with a plurality of pressed structures and a plurality of dehydration holes formed thereon. The pressed structures are formed by protrusions directed to the inside of the inner drum, where a bottom of each protrusion is of a first parallelogram, and the protrusions are arranged in rows and columns, and gaps between protrusions in adjacent columns and in adjacent rows form straight flow channels for a water flow to pass, and the dehydration holes are provided on the straight flow channels.

[0009] In one embodiment, the bottom of each protrusion is formed by the first parallelogram of a same shape, and the first parallelogram is a rectangle, a square, a rhombus, or a parallelogram geometry whose adjacent sides are not equal.

[0010] In one embodiment, a center line of protrusions in a same column perpendicularly intersects with a center line of protrusions in a same row.

[0011] In one embodiment, a distance between adjacent protrusions in a same column is same as that between adjacent protrusions in a same row.

[0012] In one embodiment, each protrusion is formed by a top surface and a transitional surface, wherein the top surface and the transitional surface have different curvatures, such that each connecting line from the protrusion center to any point on the bottom of the protrusion along an outer wall of the protrusion comprises two arcs with different curvatures.

[0013] In one embodiment, each protrusion is formed by a top surface and a transitional surface, wherein intersecting lines of the top surface and the transitional surface form a second parallelogram that is same as the first parallelogram in geometry and different from the first parallelogram in size, wherein a length and a width of the second parallelogram are less than a length and a width of the first parallelogram, respectively.

[0014] In one embodiment, adjacent side edges of the first parallelogram at the bottom of the protrusion and the second parallelogram at the intersecting lines of the top and transitional surfaces of the protrusion are transitionally connected by through rounded corners.

[0015] In one embodiment, a side edge of the first and second parallelograms gradually bends outwards from two ends to the middle of the side edge.

[0016] In one embodiment, the straight flow channels form a flow channel network formed by crossing a plurality of transverse flow channels disposed in parallel over a plurality of longitudinal flow channels disposed in parallel, and the dehydration holes are respectively provided at crossings of the transverse flow channels and the longitudinal flow channels.

[0017] In one embodiment, each straight longitudinal flow channel is formed by a gap between protrusions in two adjacent columns, and each straight transverse flow channel is formed by a gap between protrusions in two adjacent rows, where the straight transverse flow channel is perpendicular to the longitudinal flow channel. At least one dehydration hole is provided at the crossing of the transverse flow channel and the longitudinal flow channel.

[0018] In another aspect, the invention provides a washing machine including the foregoing inner drum.

[0019] As compared with the conventional washing machine, beneficial effects of the present invention are: the pressed structures of the foregoing shape are provided on the drum wall of the inner drum, such that flow channels arranged in a crisscross pattern are formed on the inner wall of the inner drum. Therefore, transverse and longitudinal structural strength is distributed more uniformly. More particularly, connections between the top surface and the transitional surface of each protrusion and between the transitional surface and the drum wall are transited through smooth arcs, and the top surface and the transitional surface are arc-shaped, so that there is no sharp edges and corners on the inner wall of the inner drum, thereby reducing wear of clothes during a washing process.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 is a schematic structural diagram of an inner drum according to one embodiment of the present invention.

[0021] FIG. 2 is a schematic structural diagram of a drum wall of the inner drum according to one embodiment of the present invention.

[0022] FIG. 3 is a locally enlarged diagram of FIG. 2.

[0023] FIG. 4 is a schematic expansion diagram of a cross section along a line a-a of FIG. 3.

[0024] FIG. 5 is a schematic structural diagram of an exemplary drum wall of an inner drum according to one embodiment of the present invention.

[0025] FIG. 6 is a locally enlarged diagram of FIG. 5.

[0026] FIG. 7 is a schematic structural diagram of an exemplary drum wall of an inner drum according to another embodiment of the present invention.

[0027] FIG. 8 is a locally enlarged diagram of FIG. 7.

[0028] FIG. 9 is a schematic diagram of a cross-section structure along a line M-M of FIG. 8.

[0029] FIG. 10 is a schematic diagram of an exemplary cross-section structure along the line M-M of FIG. 8.

LIST OF REFERENCE NUMERALS

[0030] 1, drum wall; 2, protrusion; 3, dehydration hole; 4, longitudinal flow channel; 5, transverse flow channel; 21, first protrusion; and 22, second protrusion.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Embodiment 1

[0031] The inner drum according to this embodiment of the present invention is described in further details with reference to FIGS. 1-4.

[0032] As shown in FIGS. 1-4, a washing machine inner drum is provided to have a drum wall 1. The drum wall 1 has a plurality of pressed structures arranged as a matrix and a plurality of dehydration holes 3 provided at a lowest part of the drum wall 1. Each of the pressed structure is formed by a protrusion 2 directed to the inside of the inner drum. The protrusion 2 is enclosed by a top surface and a transitional surface. A bottom of the protrusion 2 is a rectangle connected by using arc chamfers, so that gaps between protrusions 2 in adjacent columns form straight longitudinal flow channels 4, and gaps between protrusions 2 in adjacent rows form straight transverse flow channels 5 perpendicular to the longitudinal flow channels 4. The dehydration holes 3 are respectively provided at crossings of the transverse flow channels 5 and the longitudinal flow channels 4.

[0033] By means of the foregoing arrangement, during washing of a washing machine, water in the inner drum flows along the straight longitudinal flow channel 4 and/or the transverse flow channel 5 to generate a water flow, and the water flow flows to an outer drum through the dehydration holes at the crossings. In this process, the water flow washes clothes. In this embodiment, the bottom of the protrusion 2 is a rectangle connected by using arc chamfers, or may be set to a square, a rhombus, or a parallelogram of any shape.

[0034] Referring to in FIG. 3, the drum wall 1 has a plurality of column lines that are parallel with an axial direction of the inner drum and that are arranged in equal space: C-C, D-D, and the like, and is further provided with a plurality of row lines that are perpendicular to an axis of the inner drum and that are arranged in equal space: A-A, B-B, and the like. The protrusion 2 is disposed at a crossing of each column line and each row line. The bottom of the protrusion 2 is a rectangle connected by using arc chamfers, and a center of the rectangle coincides with a crosspoint of the corresponding row line and column line. Therefore, pressed structures formed by the protrusions are uniformly arranged as a matrix on the wall of the inner drum.

[0035] As shown in FIGS. 3 and 4, in this exemplary embodiment, the protrusion 2 is enclosed by a top surface and a transitional surface with different curvatures, and the top surface and the transitional surface are transitively connected smoothly. The top surface is a curved surface that becomes lower from a center of the protrusion to a circumference. The transitional surface is a curved surface, where one end of the curved surface is transitively connected smoothly to the circumference of the top surface, and the other end is transitively connected smoothly to the drum wall 1 through rounded corners. The transitional surface is also a curved surface that becomes lower from the center of the protrusion center to the circumference, and a curvature radius of the transitional surface is less than a curvature radius of the top surface. Therefore, each connecting line from the top center of the protrusion to any point on the bottom of the protrusion along an outer wall of the protrusion includes two arcs with different curvatures, such that a surface of the protrusion has no sharp edges, thereby reducing wear of clothes during a washing process of a washing machine.

[0036] In this embodiment, intersecting lines of the top surface and the transitional surface form a rectangle that is different, in size, from the parallelogram connected to the arc chamfers at the bottom of the protrusion, but is the same in geometry. In this embodiment, the intersecting lines of the top surface and the transitional surface may also be set to a square, a rhombus, a parallelogram, a circle, or a geometry of any shape, but are exemplarily set to a shape that is different from the bottom of the protrusion in size but is the same in geometry. Projecting lines of the intersecting lines of the top surface and the transitional surface onto the drum wall are within a geometry line of the bottom of the protrusion, so as to ensure that the transitional surface gradually protrudes outwards from top to bottom.

[0037] Furthermore, each side edge of the rectangle at the bottom of the protrusion is set to a curve gradually protruding outwards from two ends to a center, so that a gap between adjacent protrusions is narrowed from the two ends to the middle. As such, widths of the longitudinal flow channel 4 and the transverse flow channel 5 are changed, and the water flow flows through channels with different widths during a washing process, thereby achieving a scrubbing effect for clothes and improving a washing effect.

[0038] In addition, a connecting end of the transitional surface and the top surface is an upper end of the transitional surface, a connecting end of the transitional surface and the drum wall 1 is a lower end of the transitional surface. The transitional surface is formed by a square conic curved surface narrowing from the lower end to the upper end. An upper end peripheral line of the conic curved surface is formed by a square peripheral line whose shape is the same as that of a peripheral line of the top surface, and a lower end peripheral line is formed by a square peripheral line that is different from the upper end peripheral line in size but is the same in shape. The upper end peripheral line and the lower end peripheral line are square peripheral lines having the same shape but different sizes, and arc chamfers are provided at four corners of the square peripheral line. A side corner of the transitional surface is formed by an arc-shaped conic curved surface narrowing inwards and from bottom up, so that a periphery of the transitional surface is enclosed by a smoothly transited curved surface, so as to reduce wear of washed clothes.

[0039] Moreover, the transitional surface is formed by a smooth curved surface whose upper and lower ends are respectively connected to the top surface and the drum wall. The transitional surface gradually bends outwards from up down, to form the curved surface smoothly extends outward from up down direction, and to make a distance between adjacent transitional surfaces gradually narrow from up down, thereby forming a flow channel 3 gradually narrowing from up down between the adjacent protrusions 2.

[0040] In one embodiment, a thickness of the drum wall 1 is set to 0.3 mm to 1 mm, and is exemplarily set to 0.5 mm. A distance between the center of the protrusion 2 and the drum wall 1 is a distance H, and a ratio of the distance H to the thickness of the drum wall is set to 10:1 to 2:1. A ratio of a perimeter of the lower end peripheral line of the transitional surface to a perimeter of the upper end peripheral line is 5:1 to 1.1:1.

[0041] In one embodiment, the transitional surface of the protrusion 2 is connected to the drum wall 1 through arc chamfers, so that a bottom of the gap between the protrusions is formed by a horizontal plane, and two sides of the horizontal plane smoothly bend upwards, to form bottoms of the longitudinal flow channel 4 and the transverse flow channel 5. In this embodiment, because the side edge of the rectangle that forms the bottom edge of the protrusion is the curve gradually protruding outwards from the two ends to the middle, narrowest positions of the longitudinal flow channel 4 and the transverse flow channel 5 are centers of corresponding edges of the adjacent protrusions. A ratio of a width of the narrowest position of the flow channel to the thickness of the drum wall is 10:1 to 1:4.

[0042] In one embodiment, the side corner of the transitional surface is formed by the arc-shaped conic curved surface narrowing inwards and from the lower end to the upper end, so that a dent whose bottom surface is a plane is formed at the crossing, enclosed by arc-shaped conic curved surfaces at corresponding side corners of four adjacent protrusions, of the longitudinal flow channel 4 and the transverse flow channel 5. A center of each dent center is provided with one circular dehydration hole 3. The dehydration hole 3 and a crosspoint of diagonal lines of top surfaces of four protrusions 2 are concentrically provided. A ratio of a diameter of the dehydration hole 3 to the thickness of the drum wall 1 is set to 4:1 to 1:1.

[0043] Connections between the top surface and the transitional surface of the protrusion and between the transitional surface and the drum wall are transited through smooth arcs, and the top surface and the transitional surface are arc-shaped, so that there is no edges and corners on the inner wall of the inner drum, thereby reducing wear of clothes during a washing process.

[0044] The protrusions arranged in columns and rows form a flow channel network formed by longitudinal and transverse flow channels 5, and the dehydration hole 3 is provided at a crossing of each longitudinal and transverse flow channel 5, so that during a drying process of a washing machine, water in an inner drum is discharged out of the inner drum through dehydration holes 3 that are provided at crossings and at the bottom of flow channels.

Embodiment 2

[0045] As shown in FIG. 5, a washing machine inner drum includes a drum wall 1 provided with a plurality of pressed structures arranged in rows and in columns and a plurality of dehydration holes 3 provided at a lowest part of the drum wall 1. Each of the pressed structure is formed by a protrusion 2 directed to the inside of the inner drum. The protrusion 2 is enclosed by a top surface and a transitional surface. Bottoms of protrusions 2 are formed by parallelograms that are the same in shape and in size, so that gaps between protrusions 2 in adjacent columns form straight longitudinal flow channels 4, and gaps between protrusions 2 in adjacent rows form straight transverse flow channels 5 crossing the longitudinal flow channels 4. The dehydration holes 3 are respectively provided at crossings of the transverse flow channels 5 and the longitudinal flow channels 4.

[0046] As shown in FIG. 6, the drum wall 1 has a plurality of row lines that are perpendicular to an axis of the inner drum and that are arranged in equal space: E-E, F-F and the like, and is further provided with a plurality of column lines that has a same crossing angle to the row lines and that are arranged in equal space: G-G, K-K, and the like. The crossing angle of the row line and the column line is the same as an angle of adjacent edges forming the parallelogram of the protrusion. One protrusion 2 is disposed at the crossing of each column line and each row line. The bottom of the protrusion 2 is a parallelogram connected by using arc chamfers, and a center of the parallelogram coincides with a crosspoint of the corresponding row line and column line. Therefore, pressed structures formed by the protrusions are uniformly arranged in rows and columns on the wall of the inner drum.

[0047] In this embodiment, a parallelogram enclosed by four lines: E-E, F-F, G-G, and K-K is a minimum unit, and a protrusion 2 is disposed at each of crosspoints, which separately correspond to an EG protrusion, an EK protrusion, an FG protrusion, and an FK protrusion. A gap between the EG protrusion and the FG protrusion and a gap between the EK protrusion and the FK protrusion form a straight transverse flow channel 5 for a water flow to pass, and a gap between the EG protrusion and the EK protrusion and a gap between the FG protrusion and the FK protrusion form a straight longitudinal flow channel 4 for a water flow to pass.

[0048] In this embodiment, at least one dehydration hole 3 is provided at the crossing of the longitudinal flow channel 4 and transverse flow channel 5. When there is a plurality of dehydration holes 3, the dehydration holes 3 are symmetrically provided relatively to a center of the minimum unit center. When there is one dehydration hole 3, a center of the dehydration hole 3 coincides with a center of the minimum unit. In this embodiment, exemplarily, two dehydration hole 3 are provided, and a center of the two dehydration holes 3 is disposed on a connecting line of a center of the EK protrusion and a center of the FG protrusion, and the two dehydration holes are symmetrical relatively to a connecting line of a center of the FK protrusion and a center of the EG protrusion.

[0049] In this embodiment, central connecting lines of adjacent protrusions that are neither in a same row nor in a same column are classified into acute connecting lines and obtuse connecting lines. The acute connecting line is a central connecting line of arc chamfers that passes through acute angles of adjacent edges of the parallelogram at the bottom of the protrusion, for example, the connecting line of the center of the EK protrusion and the center of the FG protrusion. The obtuse connecting line is a central connecting line of arc chamfers that passes through obtuse angles of adjacent edges of the parallelogram at the bottom of the protrusion, for example, the connecting line of the center of the FK protrusion and the center of the EG protrusion.

[0050] In this embodiment, centers of the dehydration holes 3 are all provided on the acute connecting line, and the two dehydration holes 3 that are provided at the crossing of the same longitudinal flow channel 4 and the same transverse flow channel 5 are symmetrical relatively to the corresponding obtuse connecting line.

[0051] In this embodiment, intersecting lines of the top surface and the transitional surface form a parallelogram that is different, in size, from the parallelogram connected to the arc chamfers at the bottom of the protrusion, but is the same in shape. In this embodiment, the intersecting lines of the top surface and the transitional surface may also be set to a square, a rhombus, a parallelogram, a circle, or a geometry of any shape, but are exemplarily set to a shape that is different from the bottom of the protrusion in size but is the same in shape. Projecting lines of the intersecting lines of the top surface and the transitional surface onto the drum wall are within a geometric line of the bottom of the protrusion, to ensure that the transitional surface gradually protrudes outwards from top to bottom.

Embodiment 3

[0052] As shown in FIGS. 7 and 8, a washing machine inner drum includes a drum wall 1 provided with a plurality of pressed structures arranged in rows and in columns and a plurality of dehydration holes 3 provided at a lowest part of the drum wall 1. Each of the pressed structures is formed by a protrusion directed to the inside of the inner drum. Protrusions include first protrusions 21 and second protrusions 22. Bottoms of the first protrusion 21 and the second protrusion 22 are both formed by parallelograms that are the same in shape but are different in size. The first protrusions 21 and the second protrusions 22 are arranged across each other, so that gaps between protrusions 2 in adjacent columns form straight longitudinal flow channels 4 whose two side walls: a left side wall and a right wall intersect and expand outwards, and gaps between protrusions 2 in adjacent rows form straight transverse flow channels 5 that are perpendicular to the longitudinal flow channels 4 and whose two side walls: a left side wall and a right wall intersect and expand outwards. The dehydration holes 3 are respectively provided at crossings of the transverse flow channels 5 and the longitudinal flow channels 4.

[0053] Referring to FIG. 8, the drum wall 1 has a plurality of row lines that are perpendicular to an axis of the inner drum and that are arranged in equal space: L-L, M-M, N-N, and the like, and further provided with a plurality of column lines that have a same crossing angle to the row lines and that are arranged in equal space: H-H, P-P, Q-Q, I-I, and the like. One protrusion 2 is disposed at a crossing of each column line and each row line. First protrusions 21 and second protrusions 22 are separately spaced in a same column and in a same row, and are disposed in manner that their centers are in equal space. The centers of the first protrusion 21 and the second protrusion 22 separately coincide with crossings of corresponding row lines and column lines.

[0054] As shown in FIG. 9, in this embodiment, distances from central points of the first protrusion 21 and the second protrusion 21 to the drum wall 1 are equal. The protrusions with different sizes are spaced, so that a water flow in a same transverse flow channel 5 and in a same longitudinal flow channel 4 moves left and right, and a speed of the water flow changes, thereby achieving a washing effect of beating clothes by changing a water flow in an inner drum.

[0055] Values of height from the central points of the first protrusion and the second protrusion to the drum wall may also be set to different values. As shown in FIG. 10, a ratio of a distance between a central point of the first protrusion 21 and the drum wall to a distance between a central point of the second protrusion 22 and the drum wall 1 is 2:1. Therefore, a surface of the inner wall of the inner drum forms a convex and concave wavy surface, so that clothes in the inner drum rubbing the wall of the inner drum during a working process of a washing machine, thereby improving washing efficiency of the washing machine.

[0056] The present invention is not limited to the foregoing examples, obvious technical solutions and various modifications and changes made to the embodiments of the present invention by a person of ordinary skill in the art without departing from the spirit and scope of the present invention shall fall within the claims of the present invention and the equivalent replacements thereof.

Claims

1. A washing machine inner drum, comprising: a drum wall being provided with a plurality of pressed structures and a plurality of dehydration holes, wherein the pressed structures are formed by protrusions directed to the inside of the inner drum, a bottom of each protrusion is of a first parallelogram, and the protrusions are arranged in rows and columns, and gaps between protrusions in adjacent columns and in adjacent rows form straight flow channels for a water flow to pass, and the dehydration holes are provided on the straight flow channels.

2. The washing machine inner drum according to claim 1, wherein the bottom of each protrusion is formed by the first parallelogram of a same shape, and the first parallelogram is a rectangle, a square, a rhombus, or a parallelogram geometry whose adjacent sides are not equal.

3. The washing machine inner drum according to claim 2, wherein a center line of protrusions in a same column perpendicularly intersects with a center line of protrusions in a same row.

4. The washing machine inner drum according to claim 1, wherein a distance between adjacent protrusions in a same column is same as that between adjacent protrusions in a same row.

5. The washing machine inner drum according to claim 1, wherein each protrusion is formed by a top surface and a transitional surface, wherein the top surface and the transitional surface have different curvatures, such that each connecting line from the protrusion center to any point on the bottom of the protrusion along an outer wall of the protrusion comprises two arcs with different curvatures.

6. The washing machine inner drum according to claim 1, wherein each protrusion is formed by a top surface and a transitional surface, wherein intersecting lines of the top surface and the transitional surface form a second parallelogram that is same as the first parallelogram in geometry and different from the first parallelogram in size, wherein a length and a width of the second parallelogram are less than a length and a width of the first parallelogram, respectively.

7. The washing machine inner drum according to claim 6, wherein adjacent side edges of the first parallelogram at the bottom of the protrusion and the second parallelogram at the intersecting lines of the top and transitional surfaces of the protrusion are transitionally connected by through rounded corners.

8. The washing machine inner drum according to claim 7, wherein a side edge of the first and second parallelograms gradually bends outwards from two ends to the middle of the side edge.

9. The washing machine inner drum according to claim 1, wherein the straight flow channels form a flow channel network formed by crossing a plurality of transverse flow channels disposed in parallel over a plurality of longitudinal flow channels disposed in parallel, and the dehydration holes are respectively provided at crossings of the transverse flow channels and the longitudinal flow channels.

10. A washing machine, comprising the inner drum according to claim 1 disposed in the washing machine.

11. The washing machine inner drum according to claim 1, wherein each straight longitudinal flow channel is formed by a gap between protrusions in two adjacent columns, and each straight transverse flow channel is formed by a gap between protrusions in two adjacent rows, wherein the straight transverse flow channel is perpendicular to the longitudinal flow channel, and at least one dehydration hole is provided at the crossing of the transverse flow channel and the longitudinal flow channel.