WO2023273573A1

WO2023273573A1 - Refrigerating and freezing apparatus

Info

Publication number: WO2023273573A1
Application number: PCT/CN2022/089331
Authority: WO
Inventors: 房雯雯; 王爱民; 陶瑞涛; 孙永升
Original assignee: 青岛海尔智能技术研发有限公司; 海尔智家股份有限公司
Priority date: 2021-07-02
Filing date: 2022-04-26
Publication date: 2023-01-05
Also published as: CN115560515A

Abstract

A refrigerating and freezing apparatus. The refrigerating and freezing apparatus comprises a box body which is defined with at least one storage compartment, at least one door body used for opening and closing the at least one storage compartment, an ice making unit disposed in the door body, and a drainage system. The drainage system comprises a flexible hose that transmits defrosted water produced by the ice making unit to the box body. In the present invention, the defrosted water produced by the ice making unit of the door body is introduced into the box body by means of the flexible hose, and the defrosted water may be directly led out without the need for a power device, so that the defrosted water of the ice making unit of the door body and defrosted water of the storage compartment of the box body may be handled together, which simplifies the structure of the door body, reduces production costs, and enables the door body to have a larger ice making and ice storage space.

Description

Freezer

technical field

The invention relates to the field of refrigerating and freezing, in particular to a refrigerating and freezing device with a door body provided with an ice making unit.

Background technique

At present, most refrigerators with ice-making compartments on the door body lead the cooling capacity of the freezer compartment into the ice-making compartment of the door body through the air duct. Condensation is easy to occur, the ice-making time is long, and the ice-making compartment is easy to mix with the freezing compartment, which affects the cleanliness of the ice cubes. However, if direct cooling and ice making are performed on the door body, not only the connection of refrigerant pipelines is complicated and difficult, the transmission distance is too long, but also effective defrosting and drainage must be achieved in a small space, which has always been something that those skilled in the art want to solve unresolved technical problems.

Considering comprehensively, it is necessary to provide a refrigerating and freezing device with a door ice-making unit, which can effectively drain water and treat defrosting water.

Contents of the invention

An object of the present invention is to overcome at least one technical defect in the prior art, and provide a refrigerator-freezer with a door ice making unit.

A further object of the invention is to increase the reliability of flexible hose connections.

Another further object of the present invention is to reduce the size of the pivot hole of the door body.

In particular, the present invention provides a refrigerating and freezing device, characterized in that it comprises:

a box body defining at least one storage compartment;

at least one door for opening and closing the at least one storage compartment; and

The ice-making unit is arranged in the door body; and the refrigerating and freezing device further includes:

A drainage system including flexible hoses for transporting defrosted water produced by the ice making unit to the tank.

Optionally, the flexible hose includes:

The spiral portion is arranged to spirally extend from one of the door body and the box body toward the other, so that the deformation of the spiral portion can adapt to the opening and closing action of the door body.

Optionally, the door body or the box body is provided with a groove, and the spiral part is located in the groove when the door body is in a closed state.

Optionally, the spiral part is arranged on the door body; and

The door body is provided with an opening, and the opening is set to pass through at least part of the circumferential side wall of the groove on the side of the groove close to the rotation axis of the door body, so that the spiral part During the opening process of the door body, it can deflect in a direction close to the rotation axis of the door body.

Optionally, the axial dimension of the groove is larger than the axial dimension of the spiral portion when the door body is at a maximum opening angle; and

The end of the spiral portion close to the box body is configured to extend to a bottom peripheral edge close to the opening.

Optionally, the spiral part is arranged on the door body and is located on a side of the rotation axis of the door body away from the box body when the door body is in an open state.

Optionally, the drainage system also includes:

Two pre-embedded pipes are at least partially pre-installed in the insulation layer of the door body and the box body respectively, and have rigidity, and the two ends of the flexible hose are respectively arranged to be connected with the two pre-embedded pipes .

Optionally, the two embedded pipes are arranged to extend vertically or obliquely downward.

Optionally, the refrigerating and freezing device also includes:

a refrigeration system for providing refrigeration to the at least one storage compartment and the ice making unit; wherein

The refrigeration system is a vapor compression refrigeration system, and the bottom of the box defines a compressor chamber for accommodating a compressor of the refrigeration system; and

The press room is provided with an evaporating pan for collecting the defrosted water generated in the storage compartment, and the drainage system is configured to guide the defrosted water generated by the ice making unit to the evaporating pan.

Optionally, the ice making unit further includes:

heat exchange fins and refrigeration pipes, the heat exchange fins are arranged below the ice making box, and the refrigeration pipes are arranged to be thermally connected with the heat exchange fins to provide cooling capacity for the ice making box;

a heating tube for heating the heat exchange fins for defrosting; and

The water receiving component is configured to receive the defrosting water generated by the heat exchange fins when the heating tube is working, and communicate with the drainage system; wherein the water receiving component includes:

The water receiving tray is arranged under the heat exchange fins to receive defrosting water;

a heating wire arranged on the bottom wall of the water receiving tray and below the bottom wall of the water receiving tray to prevent the defrosting water from being frozen in the water receiving tray;

heat insulating material, arranged below the heating wire, to reduce the influence of heating on the temperature of the environment below the heating wire; and

The lower cover plate is arranged under the heat insulating material to support the water receiving tray, the heating wire and the heat insulating material; wherein the water receiving tray is arranged to communicate with the drainage system.

The invention introduces the defrosting water generated by the door ice making unit into the box through a flexible hose, and can realize the direct export of the defrosting water without power devices, and can make the defrosting water of the ice making unit of the door and the storage of the box body The defrosting water in the compartment is processed together, which simplifies the structure of the door body, reduces the production cost, and makes the door body have a larger space for ice making and storage.

Further, the drainage system of the present invention also includes two rigid pre-embedded pipes that are at least partially pre-installed in the insulation layer of the door body and the box body, and a helically extending spiral part is provided on the flexible hose, which is not only convenient The pipeline installation of the drainage system can reduce or even avoid the extrusion and deformation of the flexible hose in the insulation layer, realize the effective communication of the pipeline, and can adapt to the change of the positional relationship between the door body and the box body during the opening and closing process, Improved connection reliability for flexible hoses.

Furthermore, in the present invention, the spiral part is arranged on the side of the rotation axis of the door body away from the box body, and grooves and openings are correspondingly provided on the door body, so as to realize the movement limit of the spiral part and make the spiral part When the door body is opened, it can deflect in a direction close to the rotation axis of the door body, further improving the reliability of the flexible hose connection, and compared with extending the flexible hose along the rotation axis of the door body (set in the rotation axis of the door body In the shaft hole), it can reduce the size of the rotating shaft hole of the door body, facilitate the assembly of the door body, and improve the thermal insulation performance of the door body.

Those skilled in the art will be more aware of the above and other objects, advantages and features of the present invention according to the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings.

Description of drawings

Hereinafter, some specific embodiments of the present invention will be described in detail by way of illustration and not limitation with reference to the accompanying drawings. The same reference numerals in the drawings designate the same or similar parts or parts. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the attached picture:

Fig. 1 is a schematic axonometric view of a refrigerator-freezer according to one embodiment of the present invention;

Fig. 2 is a schematic cross-sectional view of the door body in Fig. 1;

Fig. 3 is a schematic cross-sectional view of the ice making unit in Fig. 2;

Fig. 4 is a schematic exploded view of the water receiving assembly in Fig. 3;

Fig. 5 is a schematic axonometric view of the door body in Fig. 1 viewed from the rear to the front, wherein part of the shell of the door body is removed;

Fig. 6 is a schematic enlarged view of area A in Fig. 5;

Fig. 7 is a schematic isometric view of the refrigerating and freezing device shown in Fig. 1 viewed from the rear, with part of the shell of the box removed.

detailed description

Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in this invention without departing from the scope or spirit of this invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a further embodiment. Thus, it is intended that the present invention covers such modifications and changes as come within the scope of the appended claims and their equivalents.

Fig. 1 is a schematic isometric view of a refrigerating and freezing device 100 according to an embodiment of the present invention; Fig. 2 is a schematic cross-sectional view of the door body 120 in Fig. 1 . The refrigerating and freezing device 100 may include a box body 110 defining at least one storage compartment 111, at least one door body for opening and closing the at least one storage compartment 111, a refrigeration system, and an ice making machine for making ice cubes. Unit 140. In the present invention, at least one is one, two or more.

A door body 120 may be provided with an ice-making compartment 121 , and an ice-making unit 140 may be disposed in the ice-making compartment 121 to increase the storage space of the storage compartment 111 .

The door body 120 may include an outer shell, an ice-making liner disposed in the outer shell, and an insulating layer disposed between the outer shell and the ice-making liner. Wherein, the ice-making compartment 121 is defined by the ice-making liner, and the ice-making compartment 121 is sealed by the compartment cover plate.

The box body 110 and the door body 120 may be respectively provided with insulation layers. The insulation layer is made of insulation material. Because the insulation layer made of insulation material is well known to those skilled in the art, it is not marked in the accompanying drawings.

FIG. 3 is a schematic cross-sectional view of the ice making unit 140 in FIG. 2 . Referring to FIG. 2 and FIG. 3 , the ice making unit 140 may include an ice making box 141 , a refrigeration pipe 142 , a heat exchange fin 143 , a heating pipe 144 , a water receiving assembly 145 and at least one circulation fan 146 .

The ice making box 141 may define at least one ice making tank (not shown) for receiving water or ice cubes. There may be multiple ice-making tanks distributed along the longitudinal direction of the ice-making box 141 . On the basis of understanding this embodiment, those skilled in the art should easily know the structure of the ice making tank, so there are no marks in the drawings.

The ice making box 141 may be provided with a communication opening 124 connecting every two adjacent ice making tanks, so as to make the water volume of multiple ice making tanks uniform.

The refrigeration pipe 142 can be used to provide cold energy for the ice making tank to form ice cubes. In the present invention, the refrigerating pipe 142 can be a refrigerant evaporating pipe, and communicates with the part of the refrigerating system located in the box body 110 through a flexible hose 161 .

The heat exchanging fins 143 may be disposed below the ice making box 141 and fixedly connected with the ice making box 141 to increase the heat exchange area of the ice making box 141 and/or the cooling pipe 142 .

The heat exchange fins 143 may include a plurality of heat exchange plates uniformly distributed along the axial direction of the refrigeration pipe 142 and at least one mounting plate for fixing the plurality of heat exchange plates.

In some embodiments, the refrigeration pipe 142 is arranged on the side of the heat exchange fin 143 away from the ice making box 141, and is at least partially embedded in the heat exchange fin 143, so as to reduce the amount of cold transferred from the refrigeration pipe 142 to the ice making box 141. The speed improves the transparency and uniformity of the ice cubes.

In some other embodiments, the refrigeration pipe 142 may be sandwiched between the ice making box 141 and the heat exchanging fins 143 , so as to provide cold energy to the ice making box 141 and the heat exchanging fins 143 at the same time.

In the aforementioned two embodiments, the number of mounting plates for the heat exchange fins 143 may be one. The mounting plate can be fixedly connected with the plurality of heat exchange plates, and is arranged on a side of the plurality of heat exchange plates close to the ice making box 141 so as to be fixedly connected with the ice making box 141 . The mounting plate and multiple heat exchange plates can be integrally formed.

In some other embodiments, the refrigeration pipe 142 may include an upper refrigeration part, a lower refrigeration part, and a connecting part connecting the upper refrigeration part and the lower refrigeration part.

The upper refrigerating part may be at least partially embedded in the ice making box 141 . The lower refrigerating part can be arranged below the upper refrigerating part, and at least partly embedded in the heat exchange fins 143, so as to increase the heat exchange area between the refrigerating pipes 142 and the heat exchange fins 143, thereby improving the diffusion to the surrounding environment of the ice making unit 140. cooling efficiency.

It should be noted that "front", "back", "up", "down", "top", "bottom", "inside", "outside", "horizontal", "vertical", "far away from" and "near" The orientation or positional relationship indicated by etc. is based on the orientation or positional relationship shown in the drawings, or based on the orientation or positional relationship of each device or element in the actual use state, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating Or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the invention.

The number of mounting plates of the heat exchange fins 143 may be two, and they are respectively disposed on both axial sides of the plurality of heat exchange plates (in the axial direction of the refrigeration pipe 142 ). The two mounting plates may respectively be formed with lugs extending away from the plurality of heat exchange plates for fixed connection with the ice making box 141 .

The heating tube 144 can be sandwiched between the ice making box 141 and the heat exchange fins 143 to heat the ice making box 141 for deicing and/or heat the heat exchange fins 143 for defrosting.

The heating pipe 144 may be arranged to be in direct contact with the ice making box 141 and the heat exchange fins 143 to improve deicing and defrosting efficiency.

The water receiving component 145 can be disposed under the heat exchanging fins 143 for receiving the defrosting water flowing down from the heat exchanging fins 143 .

FIG. 4 is a schematic exploded view of the water receiving assembly 145 in FIG. 3 . Referring to FIG. 3 and FIG. 4 , the water receiving assembly 145 may include a water receiving tray 1451 , a heating wire 1452 , a heat insulating material 1453 and a lower cover 1454 .

The water receiving tray 1451 can be disposed under the heat exchange fins 143 to receive the defrosting water generated by the heat exchange fins 143 when the heating tube 144 works.

The heating wire 1452 can be arranged on the bottom wall of the water receiving tray 1451 to prevent the defrosting water from being frozen in the water receiving tray 1451 so that the defrosting water can be discharged smoothly.

The heating wire 1452 can be arranged under the water receiving tray 1451 to avoid potential safety hazards and improve the safety of the ice making unit 140 .

The thermal insulation material 1453 can be disposed under the heating wire 1452 to reduce the influence of heating on the temperature of the environment below the heating wire 1452 .

The lower cover 1454 can be disposed under the heat insulating material 1453 to support the water receiving tray 1451 , the heating wire 1452 and the heat insulating material 1453 . The lower cover plate 1454 can be fixedly connected with at least one of the driving device of the separator 147 and the box cover 148 , thereby fixing the water receiving assembly 145 , so as to facilitate the production and transportation of the ice making unit 140 .

The lower cover plate 1454 can be provided with a drain port and a wire hole, so that the defrosting water in the water receiving tray 1451 is discharged through the drain port, and the heating wire 1452 is electrically connected through the wire hole.

The projection of the heat exchange fins 143 on the vertical plane may be located in the lower cover plate 1454 to improve the structural compactness of the ice making unit 140 .

The lower cover plate 1454 may be provided with ventilation holes horizontally penetrating through the circumferential side wall of the lower cover plate 1454 to enable the heat exchange fins 143 to exchange heat with the surrounding environment.

The circulation fan 146 can be set to promote the air in the ice making compartment 121 to circulate around the ice making box 141, so as to transfer the cold energy of the ice making box 141 to every part of the ice making compartment 121, so as to facilitate the heat preservation and storage of ice cubes.

The circulating fan 146 can be further configured to suck air along the heat exchanging fins 143 , and force the cold air after heat exchange to blow out to the top of the ice making box 141 , so that the air can fully exchange heat with the heat exchanging fins 143 .

In some embodiments, the ice making unit 140 may further include a separator 147 and a box cover 148 . The separator 147 may be configured to drive the ice cubes in the ice making tank to move. Exemplarily, the separator 147 may be a rotatable lever.

The box cover 148 may be disposed above the ice making box 141 and guide the ice cubes driven by the separator 147 to the bottom of the ice making box 141 .

An ice storage box 150 may be provided below the ice making unit 140 for receiving dropped ice cubes. An ice dispenser may also be provided below the ice storage box 150 .

FIG. 5 is a schematic isometric view of the door body 120 in FIG. 1 viewed from the rear, where part of the shell of the door body 120 is removed; FIG. 6 is a schematic enlarged view of area A in FIG. 5 . Referring to Fig. 5 and Fig. 6, in particular, the refrigerating and freezing device 100 may also include a drainage system, through which the flexible hose 161 transmits the liquid defrosting water generated by the ice making unit 140 to the tank 110, so that the ice making unit 140 generates The defrosted water is processed together with the defrosted water in the storage compartment 111 of the box body 110 , which simplifies the structure of the door body 120 .

The drainage system may communicate with the water receiving component 145 of the ice making unit 140 . Specifically, the drainage system can communicate with the water receiving tray 1451 of the water receiving assembly 145 .

In some embodiments, flexible hose 161 may include a coil 1611 . The spiral portion 1611 can be configured to spirally extend from one of the door body 120 and the box body 110 toward the other, so that the deformation of the spiral portion 1611 can adapt to the opening and closing action of the door body 120 .

In the illustrated embodiment, the spiral portion 1611 can be disposed on the door body 120 so that the spiral portion 1611 is closer to the rotation axis of the door body 120 to further improve the connection reliability of the flexible hose 161 .

Hereinafter, the embodiment of the present invention will be described in detail by taking the helical part 1611 disposed on the door body 120 as an example.

In some further embodiments, the door body 120 may be provided with a groove 123 . The spiral part 1611 can be located in the groove 123 when the door body 120 is in a closed state, so as to support the spiral part 1611 , limit the stretching direction of the spiral part 1611 and facilitate the reset of the spiral part 1611 .

The door body 120 can also define an opening 124 . The opening 124 can be set to penetrate at least part of the circumferential side wall of the groove 123 on the side of the groove 123 close to the rotation axis of the door body 120, so that the spiral part 1611 can move closer to the door body 120 when the door body 120 is opened. The direction of the rotation axis is deflected to further improve the reliability of the connection of the flexible hose 161.

The axial dimension of the groove 123 may be larger than the axial dimension of the helical part 1611 at the maximum opening angle of the door body 120 to ensure the support of the groove 123 to the helical part 1611 .

The end of the helical part 1611 close to the box body 110 can be set to extend to the bottom peripheral edge of the opening 124, so that the flexible hose 161 can be moved further from the end of the helical part 1611 under the guidance of the bottom peripheral edge of the opening 124. Smoothly change direction to extend straight (or with lesser curvature) towards the box body 110 .

In some further embodiments, the screw part 1611 can be located on the side of the rotation axis of the door body 120 away from the box body 110 when the door body 120 is in an open state, so as to reduce the size of the rotation axis hole of the door body 120 and facilitate the door The assembly of the door body 120 improves the thermal insulation performance of the door body 120.

Fig. 7 is a schematic isometric view of the refrigerating-freezing device 100 shown in Fig. 1 viewed from the rear, where part of the casing of the box body 110 is removed. Referring to FIGS. 5 to 7 , in some embodiments, the drainage system may further include two embedded pipes 162 .

The two pre-embedded pipes 162 can be at least partially pre-installed in the insulation layer of the door body 120 and the box body 110 respectively, and have rigidity. The two ends of the flexible hose 161 can be respectively set to be connected with two pre-embedded pipes 162, so as to facilitate the pipeline installation of the drainage system, reduce or even avoid the occurrence of extrusion deformation of the flexible hose 161 in the insulation layer, and realize the Effective connectivity of roads.

The two pre-embedded pipes 162 can be arranged to extend vertically or obliquely downwards, so as to prevent defrosting water from accumulating in the pre-embedded pipes 162 .

The refrigeration system may be a vapor compression refrigeration system, including a compressor, a condenser, a throttling element, and an evaporator disposed in the storage compartment 111 . The refrigeration pipe 142 may be connected in parallel with the evaporator to provide cooling to at least one storage compartment 111 and the ice making unit 140 . Since the structure of the vapor compression refrigeration system is well known to those skilled in the art, it is not marked in the drawings.

The bottom of the tank 110 may define a compressor chamber 112 for accommodating a compressor and a condenser of the refrigeration system. The press chamber 112 may be located at the rear bottom of the box body 110 .

The press room 112 may be provided with an evaporation pan 164 for collecting defrosted water generated in the storage compartment 111 . The drainage system may be configured to direct the defrosted water generated by the ice making unit 140 to the evaporating pan 164 for quick evaporation under the heating action of the compressor and the condenser.

The box body 110 may be provided with a drain pipe 163 for guiding the defrosted water generated in the storage compartment 111 to the evaporating dish 164 . The projection of the drain outlet of the drain pipe 163 on the horizontal plane can fall into the evaporating dish 164 , and the drainage system can be connected with the drain pipe 163 , and then guide the defrosted water generated by the ice making unit 140 into the evaporating dish 164 .

The door body 120 may also be provided with a water dispenser for supplying water to users.

The water distributor may include a water outlet structure 131 and a water collection structure 132 disposed below the water outlet structure 131 to prevent the water flowing out of the water outlet structure 131 from polluting the indoor environment undesirably.

The door body 120 may be formed with a chamber 122 recessed backward. The water outlet structure 131 can be at least partially disposed on the top of the chamber 122. The water collecting structure 132 can be disposed at the bottom of the chamber 122 .

The ice outlet of the ice dispenser may be configured to communicate with the chamber 122 of the water dispenser, so that users can take ice.

So far, those skilled in the art should appreciate that, although a number of exemplary embodiments of the present invention have been shown and described in detail herein, without departing from the spirit and scope of the present invention, the disclosed embodiments of the present invention can still be used. Many other variations or modifications consistent with the principles of the invention are directly identified or derived from the content. Accordingly, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims

A refrigerating and freezing device, comprising:

a box body defining at least one storage compartment;

at least one door for opening and closing the at least one storage compartment; and

an ice-making unit arranged in the door body;

A drainage system including flexible hoses for transporting defrosted water produced by the ice making unit to the tank.
The refrigerator-freezer according to claim 1, wherein said flexible hose comprises:

The spiral portion is arranged to spirally extend from one of the door body and the box body toward the other, so that the deformation of the spiral portion can adapt to the opening and closing action of the door body.
The refrigerator-freezer according to claim 2, wherein

The door body or the box body is provided with a groove, and the spiral part is located in the groove when the door body is in a closed state.
The refrigerator-freezer according to claim 3, wherein

the spiral portion is disposed on the door body; and

The door body is provided with an opening, and the opening is set to pass through at least part of the circumferential side wall of the groove on the side of the groove close to the rotation axis of the door body, so that the spiral part During the opening process of the door body, it can deflect in a direction close to the rotation axis of the door body.
The refrigerator-freezer according to claim 4, wherein

The axial dimension of the groove is larger than the axial dimension of the spiral portion when the door body is at the maximum opening angle; and

The end of the spiral portion close to the box body is configured to extend to a bottom peripheral edge close to the opening.
The refrigerator-freezer according to any one of claims 2-5, wherein

The spiral part is arranged on the door body and is located on a side of the rotation axis of the door body away from the box body when the door body is in an open state.
The refrigeration and freezing device according to any one of claims 1-6, wherein the drainage system further comprises:

Two pre-embedded pipes are respectively at least partially pre-installed in the insulation layer of the door body and the box body, and have rigidity, and the two ends of the flexible hose are respectively arranged to be connected with the two tube connection.
The refrigerator-freezer according to claim 7, wherein

The two embedded pipes are arranged to extend vertically or obliquely downward.
The refrigerator-freezer according to any one of claims 1-8, further comprising:

a refrigeration system for providing refrigeration to the at least one storage compartment and the ice making unit; wherein

The refrigeration system is a vapor compression refrigeration system, and the bottom of the box defines a compressor chamber for accommodating a compressor of the refrigeration system; and

The press room is provided with an evaporating pan for collecting the defrosting water generated in the storage compartment, and the drainage system is configured to guide the defrosting water generated by the ice making unit to the evaporating pan.
The refrigerating and freezing device according to any one of claims 1-9, wherein the ice making unit further comprises:

an ice making box defining at least one ice making chute for containing water or ice cubes;

heat exchange fins and refrigeration pipes, the heat exchange fins are arranged below the ice making box, and the refrigeration pipes are arranged to be thermally connected with the heat exchange fins to provide cooling capacity for the ice making box;

a heating tube for heating the heat exchange fins for defrosting; and

The water receiving component is configured to receive the defrosting water generated by the heat exchange fins when the heating tube is working, and communicate with the drainage system; wherein the water receiving component includes:

The water receiving tray is arranged under the heat exchange fins to receive defrosting water;

a heating wire arranged on the bottom wall of the water receiving tray and below the bottom wall of the water receiving tray to prevent the defrosting water from being frozen in the water receiving tray;

heat insulating material, arranged below the heating wire, to reduce the influence of heating on the temperature of the environment below the heating wire; and

The lower cover plate is arranged under the heat insulating material to support the water receiving tray, the heating wire and the heat insulating material; wherein the water receiving tray is arranged to communicate with the drainage system.