A TUMBLE DRYER AND A DRYING METHOD

Abstract

A clothes dryer comprises an inner drum, an outer drum, an air heating and supplying means and an air duct, and at least two air chambers each in communication with the air duct. The air chambers are respectively arranged corresponding to two sides along which clothes rise or fall as the inner drum rotates, the air chamber at one side starts supplying air and the air chamber at the other side stops supplying air according to a rotation direction of the inner drum, all air chambers are distributed in the order of front and rear of the outer drum in an axial direction, and the rotation direction of the inner drum is controlled according to the distribution of the air chambers, such that air is supplied in different positions corresponding to the front part and the rear part of the inner drum at different clothes drying stages, in order to dry clothes.

Claims

1. A tumble dryer, comprising an inner drum, an outer drum, an air heating and supplying means and a duct, wherein, the tumble dryer further comprises at least two air chambers for blowing hot air from a side wall of the outer drum to the inner drum, each air chamber is communicated with the air duct and controlled to open and close independently, the air chambers are respectively arranged corresponding to two sides along which clothes rise or fall as the inner drum rotating, wherein the air chamber at one side is controlled to start supplying air and the air chamber at the other side is controlled to stop supplying air according to a rotation direction of the inner drum.

2. The tumble dryer according to claim 1, wherein, all air chambers are distributed in an order of front and rear of the outer drum in an axial direction.

3. The tumble dryer according to claim 2, wherein, an opening and closing of each air chamber and the rotation direction of the inner drum are controlled in accordance with a drying time and/or a temperature inside the outer drum and/or a humidity of the clothes.

4. The tumble dryer according to claim 1, wherein, at least one air chamber is provided corresponding to the side along which the inner drum drives the clothes to rise and fall, the opening and closing of the air chambers on both sides are switched according to forward and reverse rotation of the inner drum.

5. The tumble dryer according to claim 4, wherein, the dryer comprises a first air chamber and a second air chamber which are respectively located on a left side and a right side of the outer drum, an air supply direction respectively corresponds to a rising and falling path of the clothes by the rotation of the inner drum, during drying, the inner drum rotates forwardly and reversely, the opening and closing of the air chambers is switched, which meet conditions: the air chamber corresponding to a clothes falling path is open to supply air, the other air chamber is closed.

6. The tumble dryer according to claim 5, wherein, the dryer also comprises a third air chamber, the third air chamber is installed on a bottom of the outer drum, a blowing direction is upward.

7. The tumble dryer according to claim 6, wherein, the first chamber and the second chamber are respectively located at a front end and a rear end of the outer drum, the third air chamber is arranged in a middle.

8. The tumble dryer according to claim 1, wherein, a one-way valve is provided on an inlet pipe of each air chamber, each chamber is in communication with the air duct through a same air distribution valve, the air chambers are controlled to blow by the air distribution valve, or, each air chamber is respectively connected with the air duct, and each air chamber is correspondingly provided with an open control valve.

9. The tumble dryer according to claim 1, wherein, the air chamber comprises an air inlet and an opening, and a vent cover for blowing air is arranged on the opening, the vent cover is evenly distributed with a plurality of vent holes.

10. A drying method of the tumble dryer according to claim 1, wherein, all air chambers are distributed in an order of front and rear of the outer drum in an axial direction, the rotation direction of the inner drum is controlled according to the distribution order of each air chamber so as to supply air in front or rear positions of the inner drum for drying in different drying stages.

11. The drying method according to claim 10, wherein, the method comprises at least two stages which is an early drying stage and a late drying stage, the air chamber which blows air from a left side of the outer drum is also located at a rear end of the outer drum, and the air chamber which blows air from a right side of the outer drum is also located at a front end of the outer drum, during the early drying stage, the inner drum rotates counter-clockwise for a whole stage or most of the time, the clothes on the left side fall, the air chamber on the left side is open to supply air, the air chamber on the right side is closed; during the late drying stage, the inner drum rotates clockwise for a whole stage or most of the time, the clothes on the right side fall, the air chamber on the right side is open to supply air, the air chamber on the left side is closed.

12. The drying method according to claim 11, wherein, a lower air chamber is provided at a middle position on a lower part of the outer drum, the lower air chamber cooperates with the air chambers on both left and right sides of the outer drum to dry the clothes during the early and late drying stages, or, a mid-drying stage is added, the lower air chamber is open during the mid-drying stage, the air chambers on the left and right sides of the outer drum are closed.

13. A tumble dryer, comprising an inner drum, an outer drum and a first drying system in which air is blown in from a front/rear of the outer drum, wherein the tumble dryer also comprises a second drying system, the second drying system comprises at least two air chambers for blowing hot air from a side wall of the outer drum to the inside, each air chamber is arranged on one side along which the clothes rise when the inner drum is rotated forwardly and reversely, and each air chamber is independently controlled to blow hot air in, and the air chambers on both sides are switched on and off according to a forward and reverse rotation of the inner drum.

14. The tumble dryer according to claim 13, wherein, the first drying system is a main drying system, and the second drying system is an auxiliary drying system, during drying the second drying system controls the opening and closing of the air chambers with the first drying system to complete the drying.

15. The tumble dryer according to claim 13, wherein, all air chambers are distributed in the order of front and rear in an axial direction of the outer drum, and/or each air chamber is distributed in the circumferential direction of the outer drum.

16. (canceled)

17. The tumble dryer according to claim 13, wherein, the second drying system comprises a first air chamber and a second air chamber, the two air chambers are respectively located on a left side and a right side of the outer drum, and corresponds to a rising and falling path of the clothes driven by a rotation of the inner drum, during drying, the inner drum rotates forwardly and reversely, the opening and closing of the air chambers is switched, which meet conditions: the air chamber corresponding to a clothes falling path is open to supply air, the air chamber on the other side is closed.

18. The tumble dryer according to claim 17, wherein, the second drying system comprises a third air chamber, the third air chamber is installed on a bottom of the outer drum, and a blowing direction is upward.

19. The tumble dryer according to claim 17, wherein, the first chamber and the second chamber are respectively located at a front end and a rear end of the outer drum.

20. The tumble dryer according to claim 13, wherein, a one-way valve is provided on an inlet pipe of each air chamber, each air chamber is in communication with the air duct through a same air distribution valve, and the air chambers are controlled to blow by an air distribution valve, or, each air chamber is respectively communicated with the air duct, and each air chamber is correspondingly provided with an open control valve.

21. The tumble dryer according to claim 13, wherein, the second drying system sharing a drying means with the first drying system, and air is diverted to the first drying system and the second drying system through the air duct, or, the second drying system and the first drying system are respectively corresponding to a heating means.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 is a schematic diagram of an existing heating tube dryer;

[0044] FIG. 2 is a schematic diagram of an existing heating pump dryer;

[0045] FIG. 3 and FIG. 4 are schematic diagrams of dryers with different air ducts of the present disclosure;

[0046] FIG. 5 is a schematic diagram of a mounting structure of air chambers and an outer drum of the present disclosure;

[0047] FIG. 6 is a schematic diagram of an air chamber of the present disclosure;

[0048] FIG. 7 is a schematic diagram of a vent cover of the present disclosure;

[0049] FIG. 8 to FIG. 10 are diagrams of different embodiments of mounting structures of the air chambers and an outer drum of the present disclosure;

[0050] FIG. 11 is a schematic diagram of air chambers axially mounted on an outer drum of the present disclosure;

[0051] FIG. 12 and FIG. 13 are schematic diagrams of a second drying system of another tumble dryer cooperating with different first drying systems of the present disclosure;

[0052] FIG. 14 and FIG. 15 are diagrams of different embodiments of mounting structures of air chambers and an outer drum of another tumble dryer of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[0053] Specific embodiments of the present disclosure are further described below in detail with reference to the accompanying drawings.

[0054] As shown in FIG. 3 and FIG. 4, a dryer of the present disclosure comprises a casing 1, an outer drum 2 provided in the casing, an inner drum 3 rotatably provided in the outer drum, a heating and supplying means 4, a duct, a drive device for driving the rotation of the inner drum, and other control structures and the like (not shown) of a conventional dryer. The heating and supplying means 4 includes a heating unit and an air supplying unit, and the heating unit may employ an electric heater structure or a heat pump structure for heating the air in the air duct; the air supplying unit is an air pump or an air blower for feeding the heated air into the outer drum or extracting the hot and humid air after heat exchange with the clothes in the outer drum. In addition to the above-mentioned conventional structure, the present disclosure further comprises at least two air chambers 5 provided on a peripheral wall of the outer drum 2, supplying hot air to the drum, and communicating with the air duct. Each air chamber 5 is independently opened and closed to supply hot air, and the air chambers 5 are respectively provided on both sides along which the clothes is driven to rise and fall by the inner drum 3 rotating. The air chamber 5 is at one side is switched on according to the rotational direction of the inner drum 3, air chamber at the other side stop supplying the air. Specifically, in the drying process, according to the rotation, direction of the inner drum, the air chamber, of which the blowing direction is corresponding to the side along which the clothes fall, is controlled to open to supply air, and stop supplying air on the side along with the clothes rise. The change of the rotating direction of the inner drum causes the change of the sides along which the clothes rise and fall, therefore, the air chambers are controlled to open and close according to the direction of the rotation. However, the above rule is not fixed, it can be open to supply air on the side along which the clothes rise, on the other side it be off.

[0055] The air chambers according to the present disclosure are not necessarily located on the same circumferential cross-section of the outer drum, and each air chamber may be distributed in the order of front and rear in the axial direction of the outer drum. The opening and closing of each air chamber and the rotation direction of the inner drum are controlled in accordance with a drying time and/or a temperature inside the outer drum and/or a humidity of the clothes. It can be better to reduce the damage to clothing fibers, to achieve rapidly and uniformly drying

[0056] The heating unit for tumble dryers according to the present disclosure employs a heater or a heat pump system or other structures such as a solar heating structure. The duct employs an internal condensing-heating circulation structure or a structure in which hot and humid air is discharged to the outside after drying (see FIG. 3 and FIG. 4). As shown in FIG. 4, when the dryer adopts the internal condensing-heating circulation and structure, there is provided a condensing unit 10. As shown in FIG. 3, when the structure in which hot and humid air is discharged to the outside after drying is adopted, the outer drum 2 is provided with an exhaust port 11.

EMBODIMENT 1

[0057] As shown in FIG. 5 and FIG. 8, the dryer of the present embodiment includes a first air chamber 51 located on the left side of the outer drum 2, and a second air chamber 52 located at the right side of the outer drum 2, the left side and the right side of the outer drum 2 are defined with respect to the direction in which the user faces to the clothes dispensing opening of the dryer. The air supply direction respectively corresponds to the rising and falling path of the clothes by the rotation of the inner drum, that is, the inner drum is switched between the forward and reverse rotation, and the first air chamber 51 and the second air chamber 52 correspond to the rising and falling paths of the clothes.

[0058] During the drying process, when the inner drum 3 is rotated forwardly which is clockwise, the clothes rise on the left side of the inner drum 3, and fall on the right side of the inner drum 3. At this time, the second air chamber 52, which blows air corresponding to the clothes drop side path, is opened, and the first air chamber 51 on the other side is closed (see FIG. 9). On the other hand, when the inner drum 3 rotates reversely which is counterclockwise, the clothes rise on the right side of the inner drum 3, and fall on the left side of the inner drum 3. At, this time, the first air chamber 51, which blows air corresponding to the clothes drop side path, is opened, and the second air chamber 52 on the other side is closed (see FIG. 5). The first air chamber 51 and the second air chamber 52 are repeatedly switched on and off in response to the forward and reverse rotation of the inner drum.

EMBODIMENT 2

[0059] As shown in FIG. 5 and FIG. 8, the dryer of the present embodiment is further provided with a third air chamber 53 on the basis of the embodiment 1, the third air chamber 53 is arranged at a bottom of the outer drum 2, that is, directly below, and the blowing direction is upward. Regardless of whether the inner drum 3 is rotated forwardly or reversely, the clothes always fall in the lower part and lifts upwardly from the lower part, and the angles at which each clothes fall are different. Therefore, the third air chamber 53 can supply hot air continuously or intermittently for a long period of time, and the drying time can be further saved.

EMBODIMENT 3

[0060] As shown in FIG. 11, the clothes dryer of the present embodiment is further improved on the basis of the embodiment 1, and the first air chamber 51 is located on the left side of the outer drum 2 and rear end thereof in the axial direction, and is opposite to the end of the clothes dispensing opening 6. The second air chamber 52 is located on the right side of the outer drum 2 and front end thereof in the axial direction, and is close to the end of the clothes dispensing opening 6. The two chambers cover at least 60% of the area in the axial direction. During the drying process, the inner drum is switched to rotate forwardly and reversely, and the first air chamber and the second air chamber are open/close corresponding to the clothes rising and falling. It achieves that air intake from the side wall of the outer drum at the front and rear ends of the outer drum and makes clothes evenly dry and not cause damage to clothes, drying time is also reduced.

[0061] Further, in combination with the embodiment 2, the third air chamber 53 provided on the outer drum is located at the bottom of the outer drum 2 and in the axial middle position, that is, the third air chamber 53 is located at a position between the first air chamber 51 and the second air chamber 52 in the axial direction of the outer drum 2. The three chambers cover at least 80% of the area in the axial direction, or cover completely. The opening and the closing of the first air chamber and the second air chamber is controlled according to the clothes rising and falling which is driven by the rotation direction, the third air chamber can supply hot air continuously or intermittently for a long period of time.

[0062] The first air chamber and the second air chamber are not fixed at the rear left end or the front right side in the present embodiment, they may be arranged at the front left end or the rear right end. Or the third air chamber is at the front and rear ends, the first air chamber or the second air chamber is in the middle or other positions.

EMBODIMENT 4

[0063] As shown in FIG. 5 and FIG. 11, on the basis of the embodiment 3, in the early drying stage, the inner drum 3 of the clothes dryer rotates counterclockwise or rotates counterclockwise most of the time. The rotation of the inner drum 3 causes the clothes to tumble, and the clothes fall on the left side of the inner drum 3 and rise on the right side, and the clothes are in a stacked state on the right side. The first air chamber 51 opening and the second air chamber 52 closing, air intake from the rear end near the left side of the outer drum 2 so that the clothes at the rear side of the inner drum 3 is quickly dried. As shown in FIG. 9 and FIG. 11, in the late drying stage, the inner drum 3 of the clothes dryer rotates clockwise or rotates clockwise most of the time. The rotation of the inner drum 3 causes the clothes to tumble, the clothes fall on the right side of the inner drum 3 and the clothes on the left side are in a stacked state. The second air chamber 52 opening and the first air chamber 51 closing, air intake from the front end near the right side of the outer drum 2 so that the clothes on the front side of the inner drum 3 are collectively dried. The control method allows the intake of air at different positions and in different stages to avoid fibers of local clothes losing their elasticity due to over-drying or easily being broken that causes the clothes to be worn out.

[0064] Further, a mid-drying stage can be added, controls the opening/closing switching of the first air chamber 51 and the second air chamber 52 and adjust the proportion of time in which the inner drum rotates forward and backward. Or the third air chamber 53 is opened in the mid-drying stage and the first air chamber 51 and the second air chamber 52 on the left and right sides are closed. Or the third air chamber 53 respectively cooperates with the first air chamber 51 and the second air chamber 52 to blow air drying in the mid-drying stage.

[0065] Drying time segment can be separated in accordance with the temperature rise stage, the temperature stable stage and the second stage of temperature rise of the existing drying process, or according to the detected humidity or temperature changes. For example: in the early drying stage, the heat of the drying clothes causes the temperature to rise rapidly to about 50° C.; then the rising rate of the temperature is slow and steady. This stage is the period when the water vapor evaporates most, the heat is absorbed by the water and water is evaporated, while the temperature inside the drum rises relatively slowly. In the late drying stage, only a small amount of water is inside the drum, the temperature rise rate inside the drum will once again sharply increase, this time means close to the end of drying.

[0066] As shown in from FIG. 12 to FIG. 15, they are schematic diagrams of another tumble dryer of the present disclosure. The tumble dryer comprises a casing 1, an outer drum 2 provided in the casing, an inner drum 3 rotatably provided in the outer drum, a heating and supplying means 4, a condensing unit 10, a duct 11, a drive device for driving the rotation of the inner drum, and other control structures and the like (not shown) of a conventional dryer. The heating and supplying means 4 includes a heating unit 41 and an air supplying unit 42, and the heating unit may employ an electric heater structure or a heat pump condensing structure for heating the air in the air duct 11; the air supplying unit 42 is an air pump or an air blower for feeding the heated air into the outer drum 2 or extracting the hot and humid air after heat exchange with the clothes in the outer drum 2. The above-mentioned conventional air drying systems with front and rear air inlet and outlet belong to the first drying system of the present disclosure. In addition to the above-mentioned conventional structure, a second drying system is provided in the present disclosure. Wherein, the first drying system is a main drying system and the second drying system is an auxiliary drying system. The second drying system comprises at least two air chambers 5 provided on the peripheral wall of the outer drum 2, supplying hot air to the drum, communicating with the air duct. Each air chamber 5 is independently opened and closed to supply hot air, and the air chambers 5 are respectively provided on both sides along which the clothes are driven to rise and fall by the inner drum 3 rotating. The second drying system controls opening and closing the air chambers with the first drying system to complete drying process. The air chamber 5 at one side is switched on and off according to the rotational direction of the inner drum 3, and air chamber at the other side stop supplying the air. Specifically, in the drying process, according to the rotation direction of the inner drum, the air chamber is controlled to open to supply air corresponding to the side along which the clothes rise, and stop supplying air on the side along which the clothes fall. The change of the direction of the rotation of the inner drum causes the change of the sides along which the clothes rise and fall, therefore, the air chambers are controlled opening and closing according to the direction of the rotation. However, the above rule is not fixed, it can be open to supply air on side along which the clothes fall, on the other side it be off.

[0067] The heating unit for the dryer of the tumble dryer may use other heating means such as a solar heating structure in addition to a heater or a heat pump system, the air duct uses an internal condensing-heating circulation structure (see FIG. 12 and FIG. 13). Air duct structure in which hot and humid air after drying is discharged to the outside can be adopted.

EMBODIMENT 5

[0068] As shown in FIG. 15, the second drying system of the present disclosure comprises a first air chamber 51 located on the left side of the outer drum 2, and a second air chamber 52 located at the right side of the outer drum 2, the left side and the right side of the outer drum 2 are defined with respect to the direction in which the user is facing to the clothes dispensing opening of the dryer. The air supply direction respectively corresponds to the rising and falling path of the clothes driven by the rotation of the inner drum, that is, the inner drum is switched between the forward and reverse rotation, and the first air chamber 51 and the second air chamber 52 correspond to the rising and falling paths of the clothes.

[0069] During the drying process, when the inner drum 3 is rotated forwardly which is clockwise, the clothes rise on the left side of the inner drum 3, and fall on the right side of the inner drum 3. At this time, the first air chamber 51, which blows air corresponding to the clothes rising side path, is opened, and the second air chamber 52 on the other side is closed (see FIG. 15). On the other hand, when the inner drum 3 rotates reversely which is counterclockwise, the clothes rise on the right side of the inner drum 3, and fall on the left side of the inner drum 3. At this time, the second air chamber 52, which blows air corresponding to the clothes rising side path, is opened, and the first air chamber 51 on the other side is closed (see FIG. 14). The first air chamber 51 and the second air chamber 52 are repeatedly switched on and off in response to the forward and reverse rotation of the inner drum 3.

EMBODIMENT 6

[0070] As shown in FIG. 14, the dryer of the present embodiment is further provided with a third air chamber 53 on the basis of the embodiment 5 (see FIG. 8), the third air chamber 53 is arranged at the bottom of the outer drum 2, that is, directly below, and the blowing direction is upward. Regardless of whether the inner drum 3 is rotated forwardly or reversely, the clothes always fall in the lower part and lift upwardly from the lower part, and the angles at which each clothes fall are different. The third air chamber 53 can supply hot air continuously or intermittently for a long period of time, and the drying time can be further saved.

EMBODIMENT 7

[0071] As shown in FIG. 1 and FIG. 13, the clothes dryer of the present embodiment is further improved on the basis of the embodiment 5, and the first air chamber 51 is located on the left side of the outer drum 2 and rear end thereof in the axial direction, and opposite to the end of the clothing dispensing opening 6. The second air chamber 52 is located on the right side of the outer drum 2 and front end thereof in the axial direction, and is close to the end of the clothing dispensing opening 6. The two chambers cover at least 60% of the area in the axial direction. During the drying process, the inner drum is switched to rotate forwardly and reversely, the first air chamber and the second air chamber are open/close corresponding to the clothes rising and falling. It achieves that air intake from the side wall of the outer drum at the front and rear ends of the outer drum and makes clothes evenly dry and not cause damage to clothes, drying time is also reduced.

[0072] Further, in combination with the embodiment 6, the third air chamber 53 provided on the outer drum is located at the bottom of the outer drum 2, and in the axial middle position, that is, the third air chamber 53 is located at a position between the first air chamber 51 and the second air chamber 52 in the axial direction of the outer drum 2. The three chambers cover at least 80% of the area in the axial direction, or are completely covered. The opening and the closing of the first air chamber and the second air chamber is controlled according to the clothes rising and falling which is driven by the rotation direction, the third air chamber can supply hot air continuously or intermittently for a long period of time.

[0073] The first air chamber and the second air chamber are not fixed at the rear left end or the front right side in the present embodiment, they may be arranged at the front left end or the rear right end. Or the third air chamber is at the front and rear ends, the first air chamber or the second air chamber is in the middle or other positions.

EMBODIMENT 8

[0074] As shown in from FIG. 12 to FIG. 14, on the basis of the embodiment 7, in the early drying stage, the inner drum 3 of the clothes dryer rotates clockwise or rotates clockwise most of the time (see FIG. 15). The rotation of the inner drum 3 causes the clothes to tumble, the clothes fall on the right side of the inner drum 3 and rise on the left side, and the clothes on the left side are in a stacked state. The first air chamber 51 opening and the second air chamber 52 closing, air intake from the rear end near the left side of the outer drum 2 so that the clothes at the rear side of the inner drum 3 is quickly dried. As shown in FIG. 14, in the late drying stage, the inner drum 3 of the clothes dryer rotates counterclockwise or rotates counterclockwise most of the time. The rotation of the inner drum 3 causes the clothes to tumble, the clothes fall on the left side of the inner drum 3 and rise on the right side, and the clothes on the right side are in a stacked state. The second air chamber 52 opening and the first air chamber 51 closing, air intake from the front end near the right side of the outer drum 2 so that the clothes on the front side of the inner drum 3 are collectively dried. The control method cooperates with the first drying system covering a full range of drying to avoid fibers of local clothes losing their elasticity due to over-drying or easily being broken that causing clothing worn out.

[0075] Further, a mid-drying stage can be added, controls the opening/closing switching of the first air chamber 51 and the second air chamber 52 and adjust the proportion of time in which the inner drum rotates forward and backward. Or the third air chamber 53 is opened to in the mid-drying stage and the first air chamber 51 and the second air chamber 52 on the left and right sides are closed. Or the third air chamber 53 respectively cooperates with the first air chamber 51 and the second air chamber 52 to blow air drying in the mid-drying stage.

[0076] Drying time segment can be separated in accordance with the temperature rise stage, the temperature stable stage and the second stage of temperature rise of the existing drying process, or according to the detected humidity, or temperature changes. For example: in the early drying stage, the heat of the drying clothing causes the temperature to rise rapidly to about 50° C.; then the rising rate of the temperature is gradually slow and steady. This stage is the period when the water vapor evaporates most, the heat is absorbed by the water and water is evaporated, while the temperature inside the drum rises relatively slowly. In the late drying stage, only a small amount of water is inside the drum, the temperature rise rate inside the drum will once again sharply increase, this time means close to the end of drying.

EMBODIMENT 9

[0077] As shown in from FIG. 3 to FIG. 5 and FIG. 14, the two types of tumble dryers of the present disclosure comprise a drying structure of a washing dryer. A one-way valve 8 is provided on an inlet pipe 7 of each air chamber 5, the one-way valve 8 prevents the flow of water from entering the heating unit or prevents the wash water from leaking when the machine is in washing process. Each chamber 5 is in communication with the air duct through a same air distribution valve 9, the air chambers is controlled to open and close by the air distribution valve 9. Or, each air chamber is respectively connected with the air duct, and each air chamber is correspondingly provided with an open control valve.

[0078] As shown in from FIG. 8 to FIG. 10, the number of the air chambers 5 provided in the above mentioned two types of tumble dryers of the present disclosure is not limited to the two or three, but four or five or more. They can be added not only in the circumferential direction of the outer drum but also in the axial direction.

[0079] As shown in FIG. 6 and FIG. 7, the air chamber 5 comprises an air inlet 54 and an opening 55, and a vent cover 56 for blowing air is arranged on the opening 55. The vent covers 56 is evenly distributed with a plurality of vent holes 57. The air intake is evenly and not forming turbulence.

[0080] The above description is only preferred embodiments of the disclosure. It should be noted that without departing from the design concept of the present disclosure, various variations and improvements made to the technical solutions of the present disclosure by persons skilled in the art all belong to the protection scope of the present disclosure.