阅读说明：本技术 具有热泵系统的衣物处理设备 (Laundry treatment apparatus having heat pump system ) 是由 弗朗切斯科·卡瓦雷塔 法比奥·甘巴罗 詹尼·戈博 于 2021-04-15 设计创作，主要内容包括：本发明涉及一种衣物处理设备,其包括：柜体；以可旋转的方式容置在柜体内的滚筒；热泵系统,其使用一种或更多种易燃制冷剂；循环系统,其构造成用于使工作流体循环通过滚筒；其中,热泵系统包括热交换器,热交换器包括：金属管,金属管弯曲成限定包括多个直部段的盘管结构；各自设置有多个通孔的多个散热片,通孔容置直部段中的两个直部段,多个直部段以使得直部段的中心在切割平面垂直于直部段的横截面中沿着多条相互平行的直线对准的方式分布,金属管的外径、沿着所述相互平行的直线之中的同一直线对准的两个相邻通孔的中心之间的距离和相互平行的直线之中的两条相邻直线之间的距离根据有利的尺寸范围设置。(The present invention relates to a laundry treating apparatus, comprising: a cabinet body; a drum rotatably accommodated in the cabinet; a heat pump system using one or more flammable refrigerants; a circulation system configured to circulate a working fluid through the drum; wherein the heat pump system comprises a heat exchanger comprising: a metal tube bent to define a coiled tube structure comprising a plurality of straight sections; a plurality of fins each provided with a plurality of through holes that accommodate two of the straight sections, the plurality of straight sections being distributed in such a manner that centers of the straight sections are aligned along a plurality of mutually parallel straight lines in a cross section in which a cutting plane is perpendicular to the straight sections, an outer diameter of the metal pipe, a distance between centers of two adjacent through holes aligned along a same straight line among the mutually parallel straight lines, and a distance between two adjacent straight lines among the mutually parallel straight lines being set according to an advantageous size range.)

1. A laundry treating apparatus (10) comprising:

-a cabinet (20);

-a drum (30), said drum (30) being rotatably housed inside said cabinet (20), laundry being loadable in said drum (30);

-a heat pump system (40), the heat pump system (40) using one or more flammable refrigerants and being configured for heat exchange with a working fluid (50);

-a circulation system (60), the circulation system (60) being configured for circulating the working fluid (50) through the drum (30);

wherein the heat pump system (40) comprises a heat exchanger (70a, 70b), the heat exchanger (70a, 70b) comprising:

-a metal tube (80) in which the flammable refrigerant flows (80);

-the metal tube (80) is bent to define a coil structure comprising a plurality of straight sections (81), said plurality of straight sections (81) being parallel to each other and connected two by two at one end of the plurality of straight sections (81) by a plurality of curved sections (82);

-a plurality of fins (90), said plurality of fins (90) being stacked spaced apart from each other and in parallel, said plurality of fins (90) each being provided with a plurality of through holes (100), each through hole (100) accommodating two of said straight sections (81),

the plurality of straight sections (81) are distributed in the following manner: in a cross section of the cutting plane (Cp) perpendicular to the straight section (81), the centres (Ce) of the straight section (81) are aligned along a plurality of mutually parallel straight lines (110),

it is characterized in that the preparation method is characterized in that,

if the outer diameter (de) of the metal tube (80) is between 5mm and 9 mm:

-the distance (Tp) between the centres (Ce) of two adjacent through holes (100) aligned along the same one (110) among the mutually parallel straight lines (110) is comprised between 30 and 40mm, and the distance (Rp) between two adjacent straight lines (110) among the mutually parallel straight lines (110) is comprised between 12 and 50mm,

or

-the distance (Tp) between the centres (Ce) of two adjacent through holes (100) aligned along the same one (110) among the mutually parallel straight lines (110) is between 40 and 70mm, and the distance (Rp) between two adjacent straight lines (110) among the mutually parallel straight lines (110) is between 8 and 50 mm.

2. The laundry treating apparatus (10) according to claim 1,

if the outer diameter (de) of the metal tube (80) is between 5mm and 9mm,

the distance (Tp) between the centers (Ce) of two adjacent through holes (100) aligned along the same straight line (110) among the mutually parallel straight lines (110) is between 30mm and 40mm, and the distance (Rp) between two adjacent straight lines (110) among the mutually parallel straight lines (110) is between 12mm and 35 mm.

3. The laundry treating apparatus (10) according to claim 1,

if the outer diameter (de) of the metal tube (80) is between 5mm and 9mm,

the distance (Tp) between the centers (Ce) of two adjacent through holes (100) aligned along the same straight line (110) among the mutually parallel straight lines (110) is between 40mm and 55mm, and the distance (Rp) between two adjacent straight lines (110) among the mutually parallel straight lines (110) is between 8mm and 12 mm.

4. The laundry treatment apparatus (10) according to one or more of the preceding claims, wherein said distance (Rp) between two adjacent straight lines (110) among said mutually parallel straight lines (110) is the same for all two adjacent straight lines (110) among said mutually parallel straight lines (110).

5. The laundry treatment apparatus (10) according to one or more of the preceding claims, wherein said distance (Tp) between said centers (Ce) of two adjacent through holes (100) aligned along a same straight line (110) among said mutually parallel straight lines (110) is the same for all two adjacent through holes (100) aligned along said same straight line (110).

6. The laundry treatment apparatus (10) according to claim 5, wherein said distance (Tp) between said centers (Ce) of two adjacent through holes (100) aligned along a same straight line (110) among said mutually parallel straight lines (110) is the same for all said mutually parallel straight lines (110).

7. The laundry treatment apparatus (10) according to one or more of the preceding claims, wherein said metal tube (80) comprises an inlet portion (84) and an outlet portion (85) both protruding from a same terminal fin (91) of said plurality of stacked fins (90).

8. The laundry treatment apparatus (10) according to one or more of the preceding claims, wherein said flammable refrigerant is or comprises a hydrocarbon.

9. The laundry treatment apparatus (10) according to claim 8, wherein said flammable refrigerant is or comprises propane (R290) or propylene (R1270).

10. The laundry treatment apparatus (10) according to one or more of the preceding claims, wherein said plurality of fins (90) are made of aluminum or aluminum alloy or copper alloy, or said plurality of fins (90) comprise aluminum or aluminum alloy or copper alloy.

11. The laundry treatment apparatus (10) according to one or more of the preceding claims, wherein the peripheral edges (99) of said stacked fins (90) define overall an envelope surface (92), said envelope surface (92) comprising at least a planar portion (93), and wherein said mutually parallel straight lines (110) are perpendicular to said at least planar portion (93).

12. The laundry treatment apparatus (10) according to one or more of the preceding claims, wherein a fin of said plurality of fins (90) has a width (w) comprised between 65mm and 145mm, preferably between 95mm and 125mm, and a height (h) comprised between 110mm and 185mm, preferably between 145mm and 165 mm.

13. The laundry treatment apparatus (10) according to one or more of the preceding claims, wherein said fins (90) of the stack have a total length (L) comprised between 330mm and 370mm, preferably between 200mm and 250 mm.

14. The laundry treatment apparatus (10) according to one or more of the preceding claims, wherein said metal tube (80) is made of aluminum or aluminum alloy or copper alloy, or said metal tube (80) comprises aluminum or aluminum alloy or copper alloy.

15. Laundry treatment apparatus (10) according to one or more of the previous claims, wherein said laundry treatment apparatus (10) is a tumble dryer (11) or a washer-dryer and wherein said working fluid (50) is air, or wherein said laundry treatment apparatus (10) is a laundry washing machine and said working fluid (50) is water or water mixed with a washing/rinsing agent.

Technical Field

The present invention relates to laundry treatment apparatuses, such as laundry washing machines (also called washing machines), laundry washing-drying machines (also called washing-drying machines), tumble dryers, having a heat pump system.

Background

Conventional laundry treatment apparatuses, such as washing machines, washer-dryers, tumble-dryers, generally comprise a cabinet containing a rotatable drum in which laundry to be treated (i.e. to be washed and/or dried) can be loaded.

The working fluid (for example, depending on the type of laundry treatment apparatus and the treatment process to be applied, i.e. water, water mixed with washing/rinsing additives, air) is circulated through the drum by means of a circulation system (depending on the kind of fluid to be circulated, the circulation system for example comprising pumps, valves, fans, etc.).

In some known laundry treatment apparatuses, the working fluid is heated and/or cooled/dehumidified by a heat pump system, which typically comprises a compressor, an expansion valve, two heat exchangers (one operating as a condenser and the other as an evaporator), and a conduit fluidly connecting such elements in a closed circuit.

The heat pump system has improved energy efficiency compared to a conventional heating system using an electric heater as a heat source.

Some of the refrigerant flows through the compressor, the condenser, the expansion valve, and the evaporator, and flows through a pipe connecting these elements to each other.

The refrigerant releases heat to the working fluid by means of a condenser, and extracts heat and moisture from the working fluid by means of an evaporator. The compressor converts electromechanical energy to thermal energy by compressing refrigerant in a refrigerant circuit.

A heat exchanger of a known type, widely used in heat pump systems of laundry treatment apparatus, comprises a metal tube made of copper or aluminium in which a refrigerant flows, bent to define a coil structure comprising a plurality of straight sections, parallel to each other and connected two by two at one end thereof by a plurality of bent sections; this known heat exchanger comprises a plurality of fins, usually made of aluminium and having rectangular planes, stacked in spaced and parallel planes and comprising a plurality of through holes each housing two straight sections of metal tubes.

During operation of the heat pump system, the working fluid flows through the gaps between the fins to exchange heat with the fins, and thus with the refrigerant flowing in the metal tubes thermally connected to the fins.

At present, refrigerants mainly used in a heat pump system of a known laundry treating apparatus are Hydrofluorocarbon (HFC) refrigerants, particularly refrigerants known as R134a and R407C. Unfortunately, these refrigerants have very high Global Warming Potentials (GWPs), and therefore alternative refrigerants are beginning to be used more and more in different industries.

Possible alternative refrigerants for use in the heat pump system of the laundry treating apparatus instead of the Hydrofluorocarbon (HFC) refrigerant are hydrocarbon refrigerants such as propane (R290) and propylene (R1270).

The impact of these alternative refrigerants on the global warming potential is very small and the thermophysical properties of these alternative refrigerants make them very suitable for the typical operating conditions of heat pump systems of laundry treatment apparatuses, in particular tumble dryers and washer-dryers.

A disadvantage of these alternative refrigerants is that they are flammable and therefore, in order to limit the possible risks, regulations (e.g. IEC 60335-2-11 standard) limit the amount of refrigerant that can be charged in a heat pump system to 150g (grams).

Inside the heat pump system, when the compressor is on, it can be found that most of the refrigerant is inside the condenser, since in this heat exchanger the refrigerant is at high pressure and in a liquid state for a part of the refrigerant, and therefore has a very high density.

In contrast, the evaporator operates at a low pressure and the refrigerant contained in the evaporator is mainly a liquid-vapor mixture and superheated vapor, and therefore the density of the refrigerant is rather low.

It has been observed that limiting the refrigerant charge to 150g may negatively impact the performance of the heat pump system, particularly its energy efficiency.

Therefore, there is a need to reduce the volume of the components of the heat exchanger in which the refrigerant flows to limit the amount of refrigerant charge required by the system. On the other hand, it is important not to reduce the external surface area too much to maintain good heat exchange performance.

In particular, in order to reduce the overall volume of the single tube in which the refrigerant of the heat exchanger flows, it is possible to reduce the number of stacked fins and thus reduce the overall length of the metal tube; unfortunately, reducing the number of fins also reduces the overall heat exchange surface of the heat exchanger, which reduces the energy efficiency of the heat pump system.

Disclosure of Invention

Therefore, an object of the present invention is to obtain a laundry treatment apparatus using a heat pump system and having reduced Global Warming Potential (GWP) and improved efficiency.

Within this aim, a further object of the present invention is to obtain a laundry treatment apparatus that meets the safety regulations relating to the refrigerant of the heat pump system without reducing the overall energy efficiency.

The applicant has found that by selecting the following three specific ranges, it is possible to reduce the total internal volume of the metal tubes in which the refrigerant of the heat exchanger flows without reducing neither the length of the metal tubes nor the number of fins and therefore the total heat exchange surface: a specific range of outer diameters of the metal tubes of a finned heat exchanger, the stacked fins of which have a plurality of through holes each accommodating two mutually parallel straight sections of the metal tubes, the straight sections being distributed in such a way that centers of the straight sections are aligned along a plurality of mutually parallel straight lines in a cross section in which the cutting plane is perpendicular to the straight sections; a specific range of distances of straight lines of adjacent straight lines; and a respective specific range of distances between centers of a pair of adjacent through holes aligned along the same straight line.

The solution of the invention allows the use of flammable refrigerants with very low Global Warming Potential (GWP), such as for example propane (R290) or propylene (R1270), in the heat pump system of laundry appliances, but these flammable refrigerants need to be used in smaller quantities and therefore require a reduced volume of metal pipes in which the refrigerant of the heat exchanger flows.

In particular, the above object is solved by a laundry treating apparatus comprising:

-a cabinet;

-a drum rotatably housed inside the cabinet, in which laundry can be loaded;

-a heat pump system using one or more flammable refrigerants and configured for heat exchange with a working fluid;

-a circulation system configured for circulating a working fluid through the drum;

wherein the heat pump system comprises a heat exchanger comprising:

-a metal tube in which a flammable refrigerant flows, the metal tube being bent to define a coil structure comprising a plurality of straight sections, the plurality of straight sections being parallel to each other and connected two by two at one end of the plurality of straight sections by a plurality of curved sections;

-a plurality of fins stacked in parallel spaced apart from each other, each of the plurality of fins being provided with a plurality of through holes each accommodating two of the straight sections,

the plurality of straight sections are distributed in the following manner: in a cross-section of the cutting plane perpendicular to the straight section, the centers of the straight section are aligned along a plurality of mutually parallel straight lines,

wherein the content of the first and second substances,

if the outer diameter of the metal tube is between 5mm and 9 mm:

-the distance between the centres of two adjacent through holes aligned along the same one of the mutually parallel straight lines is between 30 and 40mm, and the distance between two adjacent ones of the mutually parallel straight lines is between 12 and 50mm,

or

-the distance between the centres of two adjacent through holes aligned along the same one of the mutually parallel straight lines is between 40 and 70mm, and the distance between two adjacent straight lines of the mutually parallel straight lines is between 8 and 50 mm.

It should be emphasized that referring to two straight lines as being adjacent (or in other words, continuous, adjacent or immediately adjacent) means that there is no other straight line between the two straight lines.

It should be emphasized that referring to two vias as being adjacent (or in other words, continuous, contiguous, or immediately adjacent) means that there is no other via between the two vias.

The specific inventive range using the distance between straight lines/the distance between through holes in combination with the specific inventive range of the outer diameter of the metal tube allows maintaining a reduced internal volume of the heat exchanger in which flammable refrigerant flows without significantly affecting the overall size of the stacked fins and thus the heat exchange performance.

Furthermore, the particular combination of the inventive ranges allows to obtain a uniform heat distribution along the fins, which avoids overheating of certain portions of the fins and also improves the heat exchange.

In an advantageous embodiment, if the outer diameter of the plurality of straight sections of the metal tube is between 5mm and 9mm, the distance between the centers of two adjacent through holes aligned along the same one of the mutually parallel straight lines is between 30mm and 40mm, and the distance between two adjacent straight lines of the mutually parallel straight lines is between 12mm and 35 mm.

In another advantageous embodiment, if the outer diameter of the plurality of straight sections of the metal tube is between 5mm and 9mm, the distance between the centers of two adjacent through holes aligned along the same one of the mutually parallel straight lines is between 40mm and 55mm, and the distance between two adjacent straight lines of the mutually parallel straight lines is between 8mm and 12 mm.

In a preferred embodiment, the distance between two adjacent straight lines among the mutually parallel straight lines is the same for all two adjacent straight lines among the mutually parallel straight lines.

The distance between the centers of two adjacent through holes aligned along the same one of mutually parallel straight lines is the same for all two adjacent through holes aligned along the same straight line. More preferably, the distance between the centers of two adjacent through holes aligned along the same straight line among the mutually parallel straight lines is the same for all the mutually parallel straight lines.

In a preferred embodiment, the metal tube includes an inlet portion and an outlet portion each protruding from the same terminal fin of the plurality of stacked fins.

Preferably, the flammable refrigerant is or includes a hydrocarbon. More preferably, the flammable refrigerant is or includes propane (R290) or propylene (R1270).

Advantageously, the plurality of fins is made of or comprises aluminum or an aluminum alloy or copper or a copper alloy.

In an advantageous embodiment, the peripheral edges of the stacked fins define overall an envelope surface comprising at least planar portions, and the mutually parallel straight lines are perpendicular to at least the planar portions.

Preferably, the fins of the plurality of metal fins have a width of between 65mm and 145mm and a height of between 110mm and 185 mm.

More preferably, the fins of the plurality of metal fins have a width of between 95mm and 125mm and a height of between 145mm and 165 mm.

Preferably, the total length of the stacked fins is between 330mm and 370 mm.

More preferably, the total length of the stacked fins is between 200mm and 250 mm.

Preferably, the metal tube is made of or comprises aluminum or an aluminum alloy or copper or a copper alloy.

In an advantageous embodiment, the laundry treatment apparatus is a tumble dryer or a washer-dryer and the working fluid is air.

In another advantageous embodiment, the laundry treatment apparatus is a laundry washing machine and the working fluid is water or water mixed with a washing/rinsing agent.

Drawings

Further advantages and features of the laundry treatment apparatus according to the present invention will become clear from the following detailed description, provided purely as a non-limiting example, in which:

fig. 1 is a schematic lateral cross-section of a laundry treatment apparatus, in particular a tumble dryer, according to the present invention;

fig. 2 is a schematic side view of a heat exchanger of a laundry treating apparatus according to the present invention;

FIG. 3 is a schematic cross-section of the plane Cp-Cp operation according to FIG. 2;

FIG. 4 is a rear view of the heat exchanger of FIG. 2;

FIG. 5 is a schematic front view of a fin of the heat exchanger of the previous figures;

FIG. 6 is a schematic side view of the metal tube of the heat exchanger of the previous figures;

FIG. 7 is a side schematic view of a stacked fin of a heat exchanger according to the present invention;

fig. 8 is another schematic cross-section of the plane Cp-Cp operation according to fig. 2.

In the drawings, like parts are denoted by like reference numerals.

Detailed Description

Advantageously, the laundry treatment apparatus 10 illustrated in fig. 1 is a "horizontal axis" tumble dryer; it is clear, however, that the invention can also be applied, without any substantial modifications, to drum dryers of the "vertical axis" type and to washing and washing dryers of both the "horizontal axis" type and the "vertical axis" type.

The laundry treatment apparatus, which is a tumble dryer 10 or a washing or washing dryer not shown, comprises a cabinet 20 or housing, which cabinet 20 or housing is preferably parallelepiped and is configured to be positioned on a horizontal surface 2, for example the floor of a building, preferably by means of suitable feet 21, advantageously one or more of the feet 21 may have an adjustable height in order to accommodate a horizontal surface 2, the flatness of which may not be perfect.

Advantageously, in the front wall 20a of the cabinet 20 there is preferably an access opening, not illustrated, which advantageously can be selectively closed by a loading/unloading door 4, preferably hinged to the front wall 20 a.

The laundry treating apparatus, which is the drum dryer 10 or the washing machine or the washing and drying machine, includes a drum 30 rotatably received in the cabinet 20, and laundry, not shown, may be loaded in the drum 30.

If the laundry treating apparatus is a washing machine or a washer-dryer, both not shown, the cabinet 20 also houses a washing tub, not shown, which is preferably suspended thereto by means of a spring and a pourer, also not shown, in which the drum 30 is rotatably housed.

The laundry treating apparatus 10 includes a circulation system 60, the circulation system 60 being configured to circulate the working fluid through the drum 3.

It should be emphasized that the circulation system 60 may define a closed circuit for the working fluid (i.e. the working fluid remains in this closed circuit during the laundry treatment process, the same fluid being suitably treated repeatedly passing through the drum 30), or the circulation system 60 may define an open circuit for the working fluid (i.e. the working fluid is loaded inside the laundry treatment apparatus 10 at a certain moment in the laundry treatment process and the working fluid is drained from the laundry treatment apparatus 10 at another moment in the laundry treatment process).

In an advantageous embodiment, in which the laundry treatment apparatus 10 is a tumble dryer as in the advantageous example of fig. 1 or a washing and drying machine, not illustrated, the working fluid is or comprises air (indicated by arrow 50), and the circulation system preferably comprises an air circuit 61 and one or more fans 62 configured for circulating such air 50 through the drum 3 and the air circuit 61.

If the laundry treating apparatus is a tumble dryer 10, the laundry treating apparatus may further advantageously comprise a lint filter 63, the lint filter 63 being arranged in the air circuit 61 for catching lint or fluff released from the laundry.

If the laundry treatment apparatus is a washing or washing-drying machine, both not shown, the working fluid is water or water mixed with a washing/rinsing additive or the working fluid comprises water or water mixed with a washing/rinsing additive, and the circulation system preferably comprises a water inlet circuit, not shown, adapted to supply water into a tub, also not shown, and a discharge circuit, also not shown, adapted to discharge washing/rinsing liquid from the machine.

The laundry treatment apparatus 10 advantageously comprises a heat pump system 40, for example, in the case of a tumble dryer, air 50, the heat pump system 40 being configured for heating a working fluid.

Advantageously, the heat pump system 40 may also be configured for cooling and dehumidifying the working fluid.

Preferably, the heat pump system 40 comprises a compressor, not shown, an expansion valve, also not shown, two heat exchangers 70a, 70b (one operating as a condenser and the other as an evaporator), and conduits, not shown, fluidly connecting these elements in a closed circuit.

The flammable refrigerant flows through the compressor, the condenser 70a, the expansion valve, and the evaporator 70b, and flows through a conduit connecting these elements to each other.

The flammable refrigerant releases heat to the working fluid by means of the condenser 70a, and absorbs heat and moisture from the working fluid by means of the evaporator 70 b. The compressor converts electromechanical energy into thermal energy by compressing a flammable refrigerant in a refrigerant circuit.

The flammable refrigerant is or includes a hydrocarbon, preferably propane (R290) or propylene (R1270).

The heat exchanger, for example, the condenser 70a and/or the evaporator 70b, includes a metal tube 80 in which a flammable refrigerant flows, the metal tube 80 being bent to define a coil structure including a plurality of straight sections 81, the plurality of straight sections 81 being parallel to each other and connected two by two at one end of the plurality of straight sections 81 by a plurality of bent sections 82.

Advantageously, the metal tube 80 is made of aluminum or aluminum alloy or copper alloy, or the metal tube 80 comprises aluminum or aluminum alloy or copper alloy.

The straight sections 81 are distributed in the following way: in a cross-section of the cutting plane Cp (illustrated in fig. 2) perpendicular to the straight section 81, the center Ce of the straight section 81 is aligned along a plurality of mutually parallel straight lines 110.

The heat exchanger, for example the condenser 70a and/or the evaporator 70b, comprises a plurality of fins 90, said plurality of fins 90 being stacked spaced apart and parallel to each other and each being provided with a plurality of through holes 100, each through hole 100 accommodating two of the straight sections 81 of the metal tube 80.

Advantageously, the heat sink 90 is made of aluminum or an aluminum alloy or copper or a copper alloy, or the heat sink 90 comprises aluminum or an aluminum alloy or copper or a copper alloy.

Advantageously, the through holes 100 of any heat sink 90 are each aligned with the through holes 100 of the remaining heat sinks of the stacked heat sinks 90.

Advantageously, the straight section 81 is fitted in such a way that the lateral surfaces of the straight section 81 are in close contact with the borders of the respective through hole 100, in order to obtain an efficient heat exchange between the straight section 81 and the through hole 100.

Advantageously, metal tube 80 comprises an inlet portion 84 and an outlet portion 85, inlet portion 84 and outlet portion 85 being configured for allowing the combustible refrigerant to enter/exit metal tube 80, respectively; advantageously, the inlet portion 84 and the outlet portion 85 are fluidly connected or can be fluidly connected to other elements of the heat pump system 40 in order to allow the flammable refrigerant to circulate through the respective heat exchanger 70a or 70 b.

Advantageously, as in the example of the figures, both the inlet portion 84 and the outlet portion 85 protrude from the same terminal fin 91 of the plurality of stacked fins 90, which simplifies the connection of the single pipe 83 to the other conduits of the heat pump system 40.

Advantageously, the peripheral edge 99 of the stacked fins 90 defines as a whole an envelope surface illustrated in fig. 7 and 8 with a broken line denoted by reference numeral 92, comprising at least a planar portion 93.

Preferably, the heat sink 90 has a rectangular or square plan, in which case the envelope surface 92 comprises four planar portions corresponding to the four sides of the rectangle or square.

In an advantageous embodiment, for example as in the embodiment shown in the figures, in which the fins 90 have a rectangular or square plan, and the envelope surface 92 comprises four planar portions corresponding to the four sides of the rectangle or square, the straight line 110 defined above is advantageously parallel to two sides of such a rectangle or square.

Preferably, the width "w" of the fins 90 is between 65mm and 145mm, more preferably between 95mm and 125 mm.

Preferably, the height "h" of the fins 90 is between 110mm and 185mm, more preferably between 145mm and 165 mm.

Preferably, the total length of the stacked fins 90 is between 330mm and 370mm, more preferably between 200mm and 250 mm.

According to the invention, if the outer diameter of the metal tube 80, and in particular the outer diameter de of the straight portion 81 of the metal tube 80, is between 5mm and 9 mm:

the distance Tp between the centers Ce of two adjacent through holes 100 aligned along one of the mutually parallel straight lines 110 is between 30mm and 40mm, and the distance Rp between two adjacent straight lines 110 among the mutually parallel straight lines 110 is between 12mm and 50mm, or

The distance Tp between the centers Ce of two adjacent through holes 100 aligned along one of the mutually parallel straight lines 110 is between 40mm and 70mm, and the distance Rp between two adjacent straight lines 110 among the mutually parallel straight lines 110 is between 8mm and 50 mm.

In an advantageous embodiment, if the outer diameter de of the plurality of straight sections 81 of the metal tube 80 is between 5mm and 9mm, the distance Tp between the centers Ce of two adjacent through holes 100 aligned along one of the mutually parallel straight lines 110 is between 30mm and 40mm, and the distance Rp between two adjacent straight lines 110 among the mutually parallel straight lines 110 is between 12mm and 35 mm.

In another advantageous embodiment, if the outer diameter de of the plurality of straight sections 81 of the metal tube 80 is between 5mm and 9mm, the distance Tp between the centers Ce of two adjacent through holes 100 aligned along one of the mutually parallel straight lines 110 is between 40mm and 55mm, and the distance Rp between two adjacent straight lines 110 among the mutually parallel straight lines 110 is between 8mm and 12 mm.

In a further advantageous embodiment, the distance Rp between two adjacent straight lines 110 among the mutually parallel straight lines 110 is the same for all two adjacent straight lines 110 among the mutually parallel straight lines 110.

Preferably, the distance Tp between the centers Ce of two adjacent through holes 100 aligned along one of the mutually parallel straight lines 110 is the same for all two adjacent through holes 100 aligned along the same straight line 110.

More preferably, the distance Tp between the centers Ce of two adjacent through holes 100 aligned along the same straight line 110 is the same for all the straight lines 110.

It can thus be seen how the present invention achieves the proposed aim and objects, since it allows to obtain an evaporator for a heat pump system of a laundry treatment apparatus having a relatively small volume of metal tubes in which the refrigerant flows and a large total heat exchange surface; the evaporator allows the use of a flammable refrigerant such as, for example, propane (R290) or propylene (R1270) having a very low Global Warming Potential (GWP) in a heat pump system to meet regulatory requirements relating to flammable refrigerant charge while maintaining high energy efficiency.