CN214892820U

CN214892820U - Heat pump dryer

Info

Publication number: CN214892820U
Application number: CN202120815658.3U
Authority: CN
Inventors: 张勇
Original assignee: Aineng Technology Guangzhou Co ltd
Current assignee: Aineng Technology Guangzhou Co ltd
Priority date: 2021-04-20
Filing date: 2021-04-20
Publication date: 2021-11-26
Anticipated expiration: 2031-04-20

Abstract

A heat pump dryer belongs to the technical field of drying. The heat pump dryer comprises a heat pump dryer body, a compressor, a first heat exchanger, a second heat exchanger, a throttling mechanism and a fan. A heat exchange channel is arranged in the heat pump dryer body. The first heat exchanger, the second heat exchanger and the fan are all arranged in the heat exchange channel. The fan is used for driving gas in the heat exchange channel to flow, and the gas in the heat exchange air channel sequentially flows through the second heat exchanger and the first heat exchanger. The air outlet of the compressor is connected with the inlet of the first heat exchanger, the outlet of the first heat exchanger is connected with the first port of the throttling mechanism, the second port of the throttling mechanism is connected with the inlet of the second heat exchanger, and the outlet of the second heat exchanger is connected with the air suction port of the compressor. And forming a zinc layer on the surface of the first heat exchanger and/or the second heat exchanger through the whole first heat exchanger and/or the second heat exchanger through hot dip galvanizing treatment. The zinc layer is formed by hot dip galvanizing treatment, and the zinc layer has the corrosion resistance, the service life is prolonged, and the adaptability is enhanced.

Description

Heat pump dryer

Technical Field

The utility model relates to a drying-machine field particularly, relates to a heat pump drying-machine.

Background

The principle of the heat pump dryer is a reverse Carnot principle, gas is pressurized in a compressor to become high-temperature high-pressure gas, then the high-temperature high-pressure gas enters a condenser, and in the condenser, a refrigerant is condensed and liquefied, and the released heat promotes the temperature of air in a drying room. The materials in the drying room are vaporized and evaporated in the form of hot air, and the evaporated water vapor is discharged by the moisture discharging system to achieve the purpose of drying the materials.

When a heat exchanger of the existing heat pump dryer dries some dried objects, the heat exchanger is damaged due to corrosion of the heat exchanger because the dried objects have certain corrosiveness.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a heat pump drying-machine, its corrosion resisting property that can improve the heat exchanger improves heat pump drying-machine's life.

The embodiment of the utility model is realized like this:

in a first aspect, the utility model provides a heat pump dryer, including heat pump dryer body, compressor, first heat exchanger, second heat exchanger, throttle mechanism and fan.

The heat pump dryer is characterized in that a heat exchange channel is arranged in the heat pump dryer body, the first heat exchanger, the second heat exchanger and the fan are arranged in the heat exchange channel, and the fan is used for driving gas in the heat exchange channel to flow so that the gas in the heat exchange channel sequentially flows through the second heat exchanger and the first heat exchanger.

The air outlet of the compressor is connected with the inlet of the first heat exchanger, the outlet of the first heat exchanger is connected with the first port of the throttling mechanism, the second port of the throttling mechanism is connected with the inlet of the second heat exchanger, and the outlet of the second heat exchanger is connected with the air suction port of the compressor.

And forming a zinc layer on the surface of the first heat exchanger and/or the second heat exchanger through hot dip galvanizing treatment on the whole of the first heat exchanger and/or the second heat exchanger.

Through the experiment, after the first heat exchanger and/or the second heat exchanger are integrally treated by hot dip galvanizing, the corrosion resistance of the first heat exchanger and/or the second heat exchanger is greatly improved, a plurality of corrosive substances released by the dried substances in the drying process can be improved, the corrosive substances comprise chlorine ions, ammonia ions and the like, and the service life of the heat exchanger can be greatly prolonged.

In an optional embodiment, the first heat exchanger and/or the second heat exchanger include a heat exchange coil and a plurality of sets of foils, through holes are provided on the foils, the heat exchange coil penetrates through the through holes and is connected with the foils, the heat exchange coil penetrates through parts of the foils, the axis of the heat exchange coil is perpendicular to the plane of the foils, the heat exchange coil has an inlet and an outlet, and an air duct is formed between two adjacent sets of foils.

Wherein the heat exchange coil is a carbon steel pipe, and the foil is a steel foil. The whole first heat exchanger and/or the whole second heat exchanger is subjected to hot dip galvanizing treatment, a zinc layer is formed on the surface of the first heat exchanger and/or the whole second heat exchanger and gaps between the inner wall of the through hole and the carbon steel pipe, the heat exchange coil is arranged to be the carbon steel pipe, and the foil is arranged to be the steel foil, so that the heat exchange efficiency of the heat exchanger is improved, and the cost of the heat exchanger is reduced.

In an optional embodiment, a flange is arranged on the foil around the through hole, the first heat exchanger and the second heat exchanger, or one of the first heat exchanger and the second heat exchanger is subjected to hot dip galvanizing treatment, an integral zinc layer is formed on the surface of the first heat exchanger and a gap between the flange and the heat exchange coil, and/or an integral zinc layer is formed on the surface of the second heat exchanger and a gap between the flange and the heat exchange coil. Through setting up the turn-ups, improve the area of contact of heat transfer coil and foil, improved heat exchange efficiency, connect simultaneously more stably.

In an alternative embodiment, the carbon steel tube is connected to the steel foil by a tube expansion process. The heat conduction efficiency between the heat exchange coil and the foil is improved, so that the heat exchange efficiency of the arrangement is improved. Through the arrangement of the diversion trench, water condensed by the heat exchanger is guided to a water collecting position as quickly as possible, meanwhile, the surface area of the foil can be enlarged, and the heat exchange efficiency is improved.

In an alternative embodiment, the foil is provided with a guiding groove communicated with the through hole, and the guiding groove is used for guiding the liquid on the surface of the foil away from the foil.

In an optional embodiment, the flow guide groove includes a main flow channel and at least one set of sub flow channels, the sub flow channels include a first flow channel and a second flow channel, the main flow channel is vertically disposed on the foil, one end of the first flow channel is communicated with the main flow channel, the other end of the first flow channel is communicated with the through hole, one end of the second flow channel is communicated with the through hole, and the other end of the second flow channel extends towards a direction away from the through hole. Condensed water formed near the heat exchange coil is guided into the diversion trench as fast as possible, and then the condensed water is guided to the water collection position from the diversion trench as fast as possible, and meanwhile, the surface area of the foil can be enlarged, and the heat exchange efficiency is improved.

In an optional embodiment, there are a plurality of through holes, the through holes are arranged on the foil in multiple rows, the number of the secondary flow channels corresponds to the number of the through holes, the primary flow channel is disposed between two adjacent rows of the through holes, and each through hole is communicated with the primary flow channel through the first flow channel.

In an alternative embodiment, the foil further comprises a plurality of third flow channels, one end of each third flow channel is communicated with one through hole at two ends of each row and extends towards the side wall of the foil, and the third flow channels are parallel to the main flow channels.

In an alternative embodiment, the primary flow channels include a first primary flow channel, a second primary flow channel, a third primary flow channel, and a fourth primary flow channel, the first main flow passage and the second main flow passage are positioned at two sides of the through hole, one end of the first flow passage is communicated with the first main flow passage, the other end of the first flow passage is communicated with the through hole, a first included angle is formed between the first flow channel and the first main flow channel, one end of the second flow channel is communicated with the through hole, the other end of the second flow channel is communicated with the second main flow channel, a second included angle is formed between the second flow channel and the second main flow channel, the first included angle is equal to the second included angle, the third main flow channel is positioned at one side of the first main flow channel, and is arranged with first sprue interval, the fourth sprue is located one side of second sprue to with second sprue interval sets up.

In an optional embodiment, the heat pump dryer further comprises a water pan, the water pan is arranged below the second heat exchanger, a flow guide pipe is arranged on the water pan, and the flow guide pipe is used for guiding liquid in the water pan out of the heat pump dryer body.

The embodiment of the utility model provides a pair of heat pump drying-machine's beneficial effect includes:

by adopting the mode of hot dipping zinc to the first heat exchanger and/or the second heat exchanger, the zinc layer is integrally formed on the surface of the first heat exchanger and/or the second heat exchanger, the corrosion resistance of the heat exchanger is improved, the service life of the heat exchanger is prolonged, and the adaptability is enhanced. Through setting up the foil into steel foil, heat exchange coil adopts the carbon steel pipe, practices thrift the cost to heat exchange efficiency has further been promoted. The peripheries of the foil through holes are provided with flanges and connected with the heat exchange coil in a pipe expanding mode, and the heat exchange efficiency and the connection stability are improved. Through set up the guiding gutter on the foil, the guiding gutter has then improved heat exchange efficiency, reduces the windage. The service life and the adaptability of the heat exchanger are integrally improved, and the heat exchange efficiency of the heat exchanger is further improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic view of the overall structure of a heat pump dryer according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a second heat exchanger according to an embodiment of the present invention;

fig. 3 is a schematic view of another perspective structure of a second heat exchanger according to an embodiment of the present invention;

FIG. 4 is a schematic view of a foil according to an embodiment of the present invention;

FIG. 5 is a schematic view of another embodiment of a foil according to the present invention;

FIG. 6 is a schematic view of another embodiment of a foil according to the present invention;

FIG. 7 is a schematic view of another embodiment of a foil according to the present invention;

FIG. 8 is a schematic view of another embodiment of a foil according to the present invention;

fig. 9 is another schematic diagram of a foil according to an embodiment of the present invention.

100-heat pump dryer; 110-heat pump dryer body; 120-a compressor; 130-a first heat exchanger; 140-a second heat exchanger; 150-a throttle mechanism; 160-a fan; 111-heat exchange channels; 141-heat exchange coil; 143-a foil; 145-through holes; 147-flanging; 149-diversion trench; 151-a main flow channel; 152-secondary flow path; 153-a first flow channel; 154-a second flow channel; 155-a third flow channel; 156-a first primary flow channel; 157-a second main flow channel; 158-a third primary flow channel; 159-a fourth primary channel; 170-a water pan; 180-a flow guide pipe.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the position or positional relationship based on the position or positional relationship shown in the drawings, or the position or positional relationship which is usually placed when the product of the present invention is used, and are only for convenience of description and simplification of the description, but do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal", "vertical" and the like do not imply that the components are required to be absolutely horizontal or pendant, but rather may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1, the present embodiment provides a heat pump dryer 100, which includes a heat pump dryer body 110, a compressor 120, a first heat exchanger 130, a second heat exchanger 140, a throttling mechanism 150, and a fan 160. The exhaust port of the compressor 120 is connected to the inlet of the first heat exchanger 130, and the outlet of the first heat exchanger 130 is connected to the first port of the throttling mechanism 150. A second port of the throttling mechanism 150 is connected to an inlet of the second heat exchanger 140, and an outlet of the second heat exchanger 140 is connected to a suction port of the compressor 120.

A heat exchange channel 111 is arranged in the heat pump dryer body 110, the first heat exchanger 130, the second heat exchanger 140 and the fan 160 are all arranged in the heat exchange channel 111, and the fan 160 is used for driving gas in the heat exchange channel 111 to flow, so that the gas in the heat exchange channel sequentially flows through the second heat exchanger 140 and the first heat exchanger 130.

In this embodiment, the first heat exchanger 130 and the second heat exchanger 140 are integrally subjected to a hot dip galvanizing treatment to form a zinc layer on the surfaces of the first heat exchanger 130 and the second heat exchanger 140.

In other embodiments of the present application, the first heat exchanger 130 or the second heat exchanger 140 is entirely treated by hot dip galvanizing, so that a zinc layer is formed on the surfaces of the first heat exchanger 130 and the second heat exchanger 140.

It should be further noted that, because the first heat exchanger 130 and the second heat exchanger 140 are used according to different requirements, one of them is used as a condenser, and the other is used as an evaporator.

By adopting a zinc hot dipping mode for one of the first heat exchanger 130 and the second heat exchanger 140 or the first heat exchanger 130 and the second heat exchanger 140 as a whole, a zinc layer is integrally formed on one surface of the first heat exchanger 130 and the second heat exchanger 140 or the first heat exchanger 130 and the second heat exchanger 140, and the zinc layer has stronger corrosion resistance, so that the corrosion resistance of the first heat exchanger 130 and/or the second heat exchanger 140 can be improved, the service life of the first heat exchanger 130 and/or the second heat exchanger 140 can be prolonged, and the adaptability of the first heat exchanger 130 and/or the second heat exchanger 140 can be enhanced.

Referring to fig. 2 and 3, in the present embodiment, each of the first heat exchanger 130 and the second heat exchanger 140 includes a heat exchanging coil 141 and a plurality of sets of foils 143, and through holes 145 are formed in the foils 143. The heat exchanging coil 141 is connected with the foil 143 through the through hole 145, and the heat exchanging coil 141 passes through a portion of the foil 143 with its axis perpendicular to the plane of the foil 143. The heat exchanging coil 141 has an inlet and an outlet, and an air channel is formed between two adjacent sets of foils 143. The heat exchange coil 141 is a carbon steel pipe, and the foil 143 is a steel foil 143. The first heat exchanger 130 and the second heat exchanger 140 are subjected to a hot dip galvanizing treatment to form a zinc layer on the surfaces of the first heat exchanger 130 and the second heat exchanger 140 and in gaps between the inner walls of the through holes 145 and the carbon steel pipe.

In other embodiments of the present application, the first heat exchanger 130 may be another type of heat exchanger, such as a fin type, a tube plate type, etc., and is used as an evaporator. The second heat exchanger 140 is used as a condenser and comprises a heat exchange coil 141 and a plurality of groups of foils 143, and through holes 145 are formed in the foils 143. The heat exchanging coil 141 is connected with the foil 143 through the through hole 145, and the heat exchanging coil 141 passes through a portion of the foil 143 with its axis perpendicular to the plane of the foil 143. The heat exchanging coil 141 has an inlet and an outlet, and an air channel is formed between two adjacent sets of foils 143. The heat exchange coil 141 is a carbon steel pipe, and the foil 143 is a steel foil 143. The first heat exchanger 130 and the second heat exchanger 140 are subjected to a hot dip galvanizing treatment to form a zinc layer on the surfaces of the first heat exchanger 130 and the second heat exchanger 140 and in gaps between the inner walls of the through holes 145 and the carbon steel pipe.

By providing one or both of the first and

second heat exchangers

130 and 140 in the form of the steel foil 143 and the carbon steel tube, the cost of the steel material is lower and the strength is higher. Meanwhile, the steel foil 143 is used for heat exchange, so that the contact area between the steel foil 143 and the outside is larger, and the heat exchange effect is better.

In this embodiment, the flanges 147 are disposed on the foils 143 around the through holes 145, and the first heat exchanger 130 and the second heat exchanger 140 are integrally subjected to a hot dip galvanizing process, so that an integral zinc layer is formed on the surface of the first heat exchanger 130 and the gap between the flanges 147 and the heat exchange coil 141. An integral zinc layer is formed on the surface of the second heat exchanger 140 and the gap between the flange 147 and the heat exchange coil 141.

Note that the flanges 147 and the foils 143 may be manufactured by a process such as stamping, and the flanges 147 of the foils 143 are integrally formed. The contact area of the heat exchange coil 141 and the foil 143 is increased by arranging the flanging 147, so that the heat exchange effect is better. At the same time, the stability of the mounting of the foil 143 can be improved.

In this embodiment, the carbon steel pipe is connected to the foil 143 by a pipe expansion process. The outer diameter of the carbon steel tube is thickened by using tube expansion treatment, so that the foil 143 is better matched with the carbon steel tube.

Referring to fig. 4, the foil 143 is provided with a guiding groove 149 communicated with the through hole 145, and the guiding groove 149 is used for guiding the liquid on the surface of the foil 143 away from the foil 143.

It should be noted that when the first heat exchanger 130 and the second heat exchanger 140 are used as condensers, the precooling of the air may cause the water drops condensed on the foil 143 to adhere to the foil 143, thereby affecting the heat exchange efficiency. The water guide grooves are formed in the foils 143, so that the water guide grooves can collect water on the surfaces of the foils 143, and then guide the collected water away from the foils 143, and the purpose of improving the heat exchange efficiency is achieved. Meanwhile, the water guide grooves are arranged, so that the heat exchange area of the foils 143 is increased, and the heat exchange efficiency is higher.

Referring to fig. 4, in the present embodiment, the flow guiding groove 149 includes a main flow channel 151 and at least one set of sub flow channels 152, the sub flow channels 152 include a first flow channel 153 and a second flow channel 154, the main flow channel 151 is vertically disposed on the foil 143, one end of the first flow channel 153 is communicated with the main flow channel 151, the other end is communicated with the through hole 145, one end of the second flow channel 154 is communicated with the through hole 145, and the other end extends in a direction away from the through hole 145.

In use, due to the relatively low temperature near the heat exchanging coil 141, a large amount of condensed water is collected near the through holes 145 of the foils 143, and the condensed water near the through holes 145 is guided into the main flow channel 151 by the first flow channel 153 and is guided away from the foils 143 through the main flow channel 151. The phenomenon that the condensed water is adsorbed on the foil 143 to influence the heat exchange efficiency of the heat exchanger is avoided. The second flow channel 154 extends away from the through hole 145, and may be inclined downward or in other directions, and the main purpose of the second flow channel is to collect the condensed water.

Referring to fig. 5, in the present embodiment, a plurality of through holes 145 are formed, the through holes 145 are arranged on the foil 143 in multiple rows, the number of the sub channels 152 corresponds to the number of the through holes 145, the main channel 151 is disposed between two adjacent rows of the through holes 145, and each of the through holes 145 is communicated with the main channel 151 through the first channel 153.

In other embodiments of the present application, the arrangement of the through holes 145 may also be set according to use requirements and design requirements, and only the through holes 145 need to be ensured to correspond to the secondary flow channels 152, and the secondary flow channels 152 can collect the condensed water around the through holes 145 into the main flow channel 151, and then lead out the foils 143 through the main flow channel 151.

Referring to fig. 5 and 9, in the present embodiment, the present invention further includes a plurality of third flow channels 155, one end of each third flow channel 155 is communicated with one through hole 145 located at both ends of each row, and extends toward the sidewall of the foil 143, and the third flow channels 155 are parallel to the main flow channels 151.

By arranging the third flow channel 155, the third flow channel 155 is located at the last through hole 145 of each row and is close to the edge of the foil 143, and the condensed water is directly and quickly guided away by arranging the third flow channel 155, so that the heat exchange efficiency is improved.

Referring to fig. 8 and 9, two adjacent rows of through holes 145 may share one main flow channel 151, and the secondary flow channels 152 on two sides of the main flow channel 151 are used to guide the condensed water around the two adjacent rows of through holes 145 into one main flow channel 151 and then guided away from the foils 143 through the main flow channel 151, so that the process of slotting can be saved, the condensed water can be well guided away from the foils 143, and the heat exchange efficiency of the heat exchanger can be improved.

Referring to fig. 6, in the present embodiment, the main flow channel 151 includes a first main flow channel 156 and a second main flow channel 157, the first main flow channel 156 and the second main flow channel 157 are located at two sides of the through hole 145, one end of the first flow channel 153 is communicated with the first main flow channel 156, the other end is communicated with the through hole 145, a first included angle is formed between the first flow channel 153 and the first main flow channel 156, one end of the second flow channel 154 is communicated with the through hole 145, the other end is communicated with the second main flow channel 157, a second included angle is formed between the second flow channel 154 and the second main flow channel 157, and the first included angle is equal to the second included angle.

Referring to fig. 7, the main flow passage 151 further includes a third main flow passage 158 and a fourth main flow passage 159, the third main flow passage 158 is located at one side of the first main flow passage 156 and is spaced from the first main flow passage 156, and the fourth main flow passage 159 is located at one side of the second main flow passage 157 and is spaced from the second main flow passage 157.

By adding the third main flow channel 158 and the fourth main flow channel 159, the efficiency of liquid guiding between two rows of through holes 145 can be improved, and meanwhile, the area of the foils 143 can be increased, so that better heat exchange is realized.

Referring to fig. 1 again, in this embodiment, the heat pump dryer further includes a water pan 170, the water pan 170 is disposed below the second heat exchanger 140, a flow guide pipe 180 is disposed on the water pan 170, and the flow guide pipe 180 is used for guiding the liquid in the water pan 170 out of the heat pump dryer body 110.

When the heat pump dryer is used, the second heat exchanger 140 is used as a condenser, the water receiving tray 170 and the lower portion of the second heat exchanger 140 can contain condensed water, and the condensed water is dried by the heat pump dryer body 110, so that the purpose of drying air is achieved, and further the purpose of drying articles is achieved.

The first heat exchanger 130 and/or the second heat exchanger 140 in the heat pump dryer 100 are/is integrally formed in a hot dip galvanizing manner, so that a zinc layer is integrally formed on the surface of the first heat exchanger 130 and/or the second heat exchanger 140, and the zinc layer has strong corrosion resistance, so that the corrosion resistance of the first heat exchanger 130 and/or the second heat exchanger 140 can be improved, the service life of the heat exchanger is prolonged, and the adaptability of the heat exchanger is enhanced.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A heat pump dryer is characterized by comprising a heat pump dryer body, a compressor, a first heat exchanger, a second heat exchanger, a throttling mechanism and a fan;

a heat exchange channel is arranged in the heat pump dryer body, the first heat exchanger, the second heat exchanger and the fan are all arranged in the heat exchange channel, and the fan is used for driving gas in the heat exchange channel to flow so that the gas in the heat exchange channel flows through the second heat exchanger and the first heat exchanger in sequence;

an exhaust port of the compressor is connected with an inlet of the first heat exchanger, an outlet of the first heat exchanger is connected with a first port of the throttling mechanism, a second port of the throttling mechanism is connected with an inlet of the second heat exchanger, and an outlet of the second heat exchanger is connected with an air suction port of the compressor;

2. The heat pump dryer of claim 1, wherein the first heat exchanger and/or the second heat exchanger comprises a heat exchange coil and a plurality of sets of foils, through holes are formed in the foils, the heat exchange coil passes through the through holes to be connected with the foils, the heat exchange coil passes through the parts of the foils, the axis of the heat exchange coil is perpendicular to the plane of the foils, the heat exchange coil is provided with an inlet and an outlet, and an air channel is formed between two adjacent sets of foils; wherein:

the heat exchange coil is a carbon steel pipe, and the foil is a steel foil;

and after the first heat exchanger and/or the second heat exchanger are/is subjected to hot dip galvanizing treatment, a zinc layer is formed in a gap between the inner wall of the through hole and the carbon steel pipe.

3. The heat pump dryer according to claim 2, wherein a flange is provided on the foil around the through hole, and after the first heat exchanger and/or the second heat exchanger are subjected to a hot dip galvanizing treatment, the surface of the first heat exchanger and a gap between the flange and the heat exchange coil form an integral zinc layer, and/or the surface of the second heat exchanger and a gap between the flange and the heat exchange coil form an integral zinc layer.

4. A heat pump dryer according to claim 2 or 3, wherein said carbon steel pipe is subjected to a pipe expansion process so that said carbon steel pipe is connected to said steel foil.

5. A heat pump dryer according to claim 2, wherein said foil is provided with channels communicating with said through holes, said channels being adapted to conduct liquid from the surface of said foil away from said foil.

6. The heat pump dryer according to claim 5, wherein the guiding gutter includes a main flow channel and at least one set of sub flow channels, the sub flow channels include a first flow channel and a second flow channel, the main flow channel is vertically disposed on the foil, one end of the first flow channel communicates with the main flow channel, the other end of the first flow channel communicates with the through hole, one end of the second flow channel communicates with the through hole, and the other end of the second flow channel extends in a direction away from the through hole.

7. The heat pump dryer according to claim 6, wherein the through holes are plural, the plural through holes are arranged on the foil in plural rows, the number of the sub-channels corresponds to the number of the through holes, the main channel is disposed between two adjacent rows of the through holes, and each of the through holes is communicated with the main channel through the first channel.

8. The heat pump dryer of claim 7, further comprising a plurality of third flow channels, one end of each of the third flow channels communicates with one of the through holes at both ends of each of the columns and extends toward the side wall of the foil, and the third flow channels are parallel to the main flow channels.

9. The heat pump dryer according to claim 7, wherein the main flow channel includes a first main flow channel, a second main flow channel, a third main flow channel and a fourth main flow channel, the first main flow channel and the second main flow channel are located at two sides of the through hole, one end of the first flow channel is communicated with the first main flow channel, the other end of the first flow channel is communicated with the through hole, a first included angle is formed between the first flow channel and the first main flow channel, one end of the second flow channel is communicated with the through hole, the other end of the second flow channel is communicated with the second main flow channel, a second included angle is formed between the second flow channel and the second main flow channel, the first included angle is equal to the second included angle, the third main flow channel is located at one side of the first main flow channel and is spaced from the first main flow channel, the fourth main flow channel is located at one side of the second main flow channel, and is arranged at intervals with the second main flow channel.

10. The heat pump dryer according to any one of claims 1-3 and 5-9, further comprising a water pan disposed below the second heat exchanger, wherein a flow guide pipe is disposed on the water pan, and the flow guide pipe is used for guiding the liquid in the water pan out of the heat pump dryer body.