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,衣物能够装载在滚筒中；热泵系统,其使用一种或更多种易燃制冷剂且构造成用于与工作流体进行热交换；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：易燃制冷剂在其中流动的多个金属管；多个散热片,该多个散热片彼此间隔并平行地堆叠并且各自设置有适于容置金属管中的一个金属管的四个或更多个通孔,其中,散热片中的每一个散热片的四个或更多个通孔中的至少两个通孔中的每个通孔容置金属管中的一个金属管,其中,散热片中的每一个散热片的四个或更多个通孔中的至少两个通孔不容置金属管中的任何金属管。(The present invention relates to a laundry treating apparatus, comprising: a cabinet body; a drum rotatably received within 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 to circulate a working fluid through the drum, wherein the heat pump system includes a heat exchanger including: a plurality of metal tubes in which a flammable refrigerant flows; a plurality of fins stacked in parallel spaced apart from each other and each provided with four or more through holes adapted to receive one of the metal tubes, wherein each of at least two of the four or more through holes of each of the fins receives one of the metal tubes, wherein at least two of the four or more through holes of each of the fins do not receive any of the metal tubes.)

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 plurality of metal tubes (80), in which said flammable refrigerant flows (80);

-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 four or more through holes (100) adapted to receive one of said metal tubes (80),

wherein each through hole (101) of at least two through holes (101) of the four or more through holes (100) of each of the fins (90) accommodates one metal tube (80) of the metal tubes (80),

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

at least two of the four or more through-holes (100) of each of the fins (90) do not receive any of the metal tubes (80) (102).

2. The laundry treatment apparatus (10) according to claim 1, wherein 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 four or more through holes (100) of each of said fins (90) are positioned on the respective fin (90) to define at least one first row (160) perpendicular to said planar portion (93) and/or at least one second row (150) perpendicular to said first row (160).

3. The laundry treatment apparatus (10) according to claim 2, wherein at least two through holes (102) of said four or more through holes (100) not accommodating any of said metal tubes (80) belong to a same second row (150).

4. Laundry treatment apparatus (10) according to claim 3, wherein at least one through hole (101) of said through holes (101) accommodating one metal tube (80) of said metal tubes (80) is provided in said same second row (150) between said at least two through holes (102) not accommodating any metal tube (80) of said metal tubes (80).

5. The laundry treatment apparatus (10) according to claim 2 or 3 or 4, wherein at least two through holes (102) of said four or more through holes (100) not accommodating any of said metal tubes (80) belong to a same first row (160).

6. Laundry treatment apparatus (10) according to claim 5, wherein at least one through hole (101) of said through holes (101) accommodating one metal tube (80) of said metal tubes (80) is provided in said same first row (160) between said at least two through holes (102) not accommodating any metal tube (80) of said metal tubes (80).

7. The laundry treatment apparatus (10) according to one or more of claims 2 to 6, wherein said fins (90) comprise at least two second rows (150) of said second rows (150), and wherein at least two through holes (102) of said four or more through holes (100) that do not house any of said metal tubes (80) belong to two adjacent second rows (150).

8. The laundry treatment apparatus (10) according to one or more of claims 2 to 7, wherein said fins (90) comprise at least two first rows (160) of said first rows (160), and wherein at least two through holes (102) of said four or more through holes (100) that do not accommodate any of said metal tubes (80) belong to two adjacent first rows (160).

9. Laundry treatment apparatus (10) according to claim 2, wherein all through holes (100) of said at least one first row (160) and/or all through holes (100) of said at least one second row (150) do not house any metal tubes (80) of said metal tubes (80).

10. The laundry treatment apparatus (10) according to one or more of the preceding claims, wherein said metal tube (80) comprises two or more straight tubes (81) parallel to each other and perpendicular to said heat sink (90), each straight tube (81) of said two or more straight tubes (81) being housed in one through hole (100) of said four or more through holes (100) of said heat sink (90), said two or more straight tubes (81) being connected two by two at one end by a curved tube (82) to define, as a whole, a single conduit (83) in which said flammable refrigerant flows.

11. The laundry treating apparatus (10) according to claim 10, wherein said single conduit (83) comprises an inlet portion (831) and an outlet portion (832), said inlet portion (831) and said outlet portion (832) being configured for allowing said flammable refrigerant to enter/exit said single conduit (83), respectively.

12. The laundry treating apparatus (10) according to claim 11, wherein said inlet portion (831) and said outlet portion (832) each protrude from a same terminal fin (91) of said plurality of fins (90).

13. The laundry treatment apparatus (10) according to one or more of the preceding claims, wherein said flammable refrigerant is or comprises a hydrocarbon, or said flammable refrigerant is or comprises propane (R290) or propylene.

14. The laundry treatment apparatus (10) according to one or more of the preceding claims, wherein said fins (90) and/or said metal tubes (80) are made of aluminum or aluminum alloy or copper alloy, or said fins (90) and/or said metal tubes (80) comprise 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 drum washer (11) or a washer-dryer and 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.

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.

A heat exchanger of a known type, widely used in heat pump systems of laundry treatment apparatus, comprises a plurality of fins, usually made of aluminium and having rectangular planes, stacked in spaced and parallel planes; the heat sink includes a plurality of through-holes in which a plurality of straight pipes made of copper or aluminum are fitted, the plurality of straight pipes being parallel to each other and perpendicular to the heat sink, wherein lateral surfaces of the plurality of straight pipes are in close contact with boundaries of the through-holes to obtain efficient heat exchange.

The straight pipes are connected two by two at one end by the bent pipe to integrally limit a single pipe in which refrigerant flows; the single tube has an inlet portion and an outlet portion that protrude from the stack of fins and are connectable to the rest of the heat pump system circuit.

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 tubes thermally connected to the fins.

The fins used to produce such heat exchangers are usually produced and sold in standard sizes and with a determined number of through holes; in order to keep the production costs down, manufacturers of laundry treatment apparatuses using such heat exchangers generally purchase available fins having external dimensions (i.e. length and width) suitable for their apparatuses, stack these available fins in spaced and parallel planes, and insert the same number of straight tubes in all through holes; typically, the tubes are fastened to the through-holes by radially expanding such tubes with a suitable tool. The straight tubes are then connected two by two at one end by curved tubes to define as a whole a single conduit in which the refrigerant flows.

Since the outer size of the heat sink and the number of through holes are determined, the degree of freedom of design is very small.

In particular, in order to reduce the total volume of the single tube in which the refrigerant flows, it is possible to reduce the number of fins stacked, and thus to reduce the length of the straight tube constituting the single 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, it is an object of the present invention to obtain a laundry treatment apparatus using a heat pump system having a reduced Global Warming Potential (GWP) and an improved efficiency, while maintaining reduced production costs.

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 and while maintaining reduced production costs.

The applicant has found that by leaving empty two or more through holes of the fins of the heat exchanger of the heat pump system (i.e. without inserting tubes therein), it is possible to reduce the total internal volume of the single tubes in which the refrigerant of the heat exchanger flows, without reducing neither the length of the single tubes constituting such a single tube nor the number of fins and therefore the total heat exchange surface, and it is also possible to use standard fins available in the market having a predetermined number of through holes, thus eliminating the need to use customized fins which may increase the production costs.

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 heat pump systems, but which need to be used in smaller quantities and therefore require a reduced volume of the single pipe 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 plurality of metal tubes in which a flammable refrigerant flows;

-a plurality of fins stacked in parallel spaced apart from each other, each provided with four or more through holes adapted to receive one of the metal tubes,

wherein each of at least two of the four or more through-holes of each of the fins receives one of the metal tubes,

wherein at least two of the four or more through-holes of each of the fins do not receive any of the metal tubes (or in other words, the at least two through-holes are not traversed by any of the metal tubes, or the at least two through-holes are free of or free of metal tubes).

Advantageously, the four or more through holes of any of the plurality of fins are each aligned with the four or more through holes of the remaining fins of the plurality of fins.

In an advantageous embodiment, the peripheral edges of the stacked fins define overall an envelope surface (i.e. a surface tangential to the peripheral edges of all stacked fins) comprising at least a planar portion, and wherein the four or more through holes of each of the fins are positioned on the respective fin so as to define at least one first row perpendicular to the planar portion and/or at least one second row perpendicular to the first row.

In a preferred embodiment, at least two through holes of the four or more through holes that do not accommodate any of the metal tubes belong to the same second row.

More preferably, at least one of the through holes accommodating one of the metal tubes is provided between at least two of the through holes not accommodating any of the metal tubes in the same second row; this advantageous embodiment ensures that the distribution of the metal tubes with respect to the fins is fairly uniform and thus that the heat distribution within the heat exchanger is fairly uniform.

In another advantageous embodiment, at least two through holes of the four or more through holes, which do not accommodate any of the metal tubes, belong to the same first row.

Preferably, in this case, at least one of the through holes accommodating one of the metal tubes is provided in the same first row between at least two of the through holes not accommodating any of the metal tubes; also, this advantageous embodiment ensures that the distribution of the metal tubes with respect to the fins is fairly uniform and thus that the heat distribution within the heat exchanger is fairly uniform.

In another advantageous embodiment, the heat sink comprises at least two second rows and at least two of the four or more through holes, which do not accommodate any of the metal tubes, belong to two adjacent second rows.

In another advantageous embodiment, the heat sink comprises at least two vertical rows and at least two of the four or more through holes not accommodating any of the metal tubes belong to two adjacent vertical rows.

It should be emphasized that the two rows are said to be adjacent, meaning that there is no other row between the two rows.

In a further advantageous embodiment, all through holes of the at least one first row and/or all through holes of the at least one second row do not accommodate any of the metal tubes.

In a preferred embodiment, the metal tube comprises two or more straight tubes parallel to each other and perpendicular to the fin, each of the two or more straight tubes being received in one of four or more through holes of the fin, the two or more straight tubes being connected two by two at one end by a bent tube to define as a whole a single conduit in which the flammable refrigerant flows.

More preferably, the single conduit includes an inlet portion and an outlet portion configured to allow the flammable refrigerant to enter/exit the single conduit, respectively.

More preferably, the inlet portion and the outlet portion each protrude from the same terminal fin of the plurality of fins.

Preferably, the flammable refrigerant is or includes a hydrocarbon.

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

In a preferred embodiment, the heat sink is made of metal.

More preferably, the fins and/or the metal tubes are made of or comprise 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 perspective view of a first embodiment of a heat exchanger of a laundry treating apparatus according to the present invention;

fig. 3 is a schematic plan view of a heat sink of the laundry treating apparatus according to the present invention;

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

FIG. 5 is a plan view of the heat exchanger of FIG. 2;

FIG. 6 is a front view of the heat exchanger of FIG. 2;

FIG. 7 is a rear view of the heat exchanger of FIG. 2;

fig. 8 is a perspective view of a second embodiment of a heat exchanger of a laundry treating apparatus according to the present invention;

FIG. 9 is a side view of the heat exchanger of FIG. 8;

FIG. 10 is a plan view of the heat exchanger of FIG. 8;

FIG. 11 is a front view of the heat exchanger of FIG. 8;

FIG. 12 is a rear view of the heat exchanger of FIG. 8;

fig. 13 is a perspective view of a second embodiment of a heat exchanger of a laundry treating apparatus according to the present invention;

FIG. 14 is a side view of the heat exchanger of FIG. 13;

FIG. 15 is a plan view of the heat exchanger of FIG. 13

FIG. 16 is a front view of the heat exchanger of FIG. 13;

FIG. 17 is a rear view of the heat exchanger of FIG. 13;

FIG. 18 is a side schematic view of a stacked fin of a heat exchanger according to the present invention;

FIG. 19 is a schematic view of four through holes of a fin of a heat exchanger according to the present invention;

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).

Advantageously, the heat exchanger, for example the condenser 70a and/or the evaporator 70b, comprises a plurality of metal tubes 80 (also simply called tubes) in which the flammable refrigerant flows and a plurality of fins 90 (advantageously metallic) stacked spaced apart from and parallel to each other, said plurality of fins 90 being each provided with four or more through holes 100 suitable for housing one of the metal tubes 80.

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

Advantageously, the peripheral edge 99 of the stacked fins 90 defines as a whole an envelope surface, shown in fig. 18 with a broken line at 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.

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

Preferably, the height 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.

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, said plurality of metal tubes 80 is made of aluminum or aluminum alloy or copper alloy, or said plurality of metal tubes 80 comprises aluminum or aluminum alloy or copper alloy.

Preferably, the metal tube 80 comprises two or more straight tubes 81 parallel to each other and perpendicular to the fins 90, each of said two or more straight tubes 81 being housed in one of the through holes 100 of the fins 90.

Advantageously, the straight pipes 81 are fitted in such a way that the lateral surfaces of the straight pipes 81 are in close contact with the borders of the respective through holes 100, so as to obtain an effective heat exchange between the straight pipes 81 and the through holes 100; this can be achieved by radially expanding such a straight tube 81 using a suitable tool not shown.

Advantageously, said two or more straight pipes 81 are connected two by two at one of their ends by a curved pipe 82 to define, as a whole, a single conduit 83 in which the flammable refrigerant flows.

Advantageously, such a single conduit 83 comprises an inlet portion 831 and an outlet portion 832, the inlet portion 831 and the outlet portion 832 being respectively configured for allowing the combustible refrigerant to enter/exit the single conduit; advantageously, the inlet portion 831 and the outlet portion 832 are fluidly connected or can be fluidly connected to other elements of the heat pump system 40, so as 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 831 and the outlet portion 832 project from the same terminal fin 91 of the plurality of fins 90, which simplifies the connection of the single pipe 83 to the other ducts of the heat pump system 40.

Advantageously, at least two through holes 101 of said four or more through holes 100 of each fin 90 accommodate one of the metal tubes 80.

Advantageously, at least two through holes 102 of the four or more through holes 100 of each fin 90 do not receive any of the metal tubes 80 (or in other words, the at least two through holes 102 are not crossed by any metal tube 80, or the at least two through holes 102 are free of metal tubes 80 or no metal tubes 80).

In this way, the number of metal tubes 80, and therefore the total internal volume of the single tube 83 in which the flammable refrigerant consisting of such metal tubes 80 flows, is reduced, while the number of fins 90, and therefore the total length of the stack of fins 90, can be relatively high, in order to obtain the desired total heat exchange surface.

In an advantageous embodiment, the four or more through holes 100 of each heat sink 90 are positioned on the respective heat sink 90 so as to define at least one first row 160 perpendicular to the planar portion 93 of the envelope surface 92 and/or at least one second row 150 perpendicular to the first row 160.

For example, in the case of four through holes 100, the four through holes 100 may all be aligned along a single first row 160, or the four through holes 100 may all be aligned along a single second row 150, or the four through holes 100 may be positioned, for example, as illustrated in fig. 19: each through-hole 100 is located at the vertex of a rectangle or square, defining, as a whole, two first rows 160 and two second rows 150.

In an advantageous embodiment, for example as in the embodiment illustrated in fig. 6, 11 and 16, at least two through holes of said four or more through holes 100, which do not house any of the tubes 80, belong to the same second row 150.

In an advantageous embodiment, for example as in the embodiment illustrated in fig. 6, at least one through hole 101 housing one metal tube 80 is provided in the same second row 150 between at least two through holes 102 not housing any metal tube 80.

In an advantageous embodiment, for example as in the embodiment illustrated in fig. 6, at least two through holes 102 of said four or more through holes 100, which do not house any metal tubes 80, belong to the same first row 160.

In a preferred embodiment, for example as in the embodiment illustrated in fig. 6, at least one through hole 101 housing one metal tube 80 is provided in the same first row 160 between at least two through holes 102 not housing any metal tube 80.

Preferably, the fins 90 comprise at least two second rows 150 and, as in the advantageous embodiment of fig. 6 and 11 for example, the at least two through holes 102 that do not house any metal tubes 80 belong to two adjacent second rows 150.

In another advantageous embodiment, the fins 90 comprise at least two first rows 160 and, as in the advantageous embodiment of fig. 11 and 16 for example, the at least two through holes 102 that do not house any metal tubes 80 belong to two adjacent first rows 160.

In another advantageous embodiment, not illustrated, all the through holes 100 of the first row 160 and/or all the through holes 100 of one second row 150 do not house any of the metal tubes 80.

Nevertheless, different positioning of the at least two through holes 102 is possible.

It can thus be seen how the present invention achieves the proposed aim and objects, since it allows to obtain, using commercially available fins (of predetermined size and of predetermined number of through holes), an evaporator for a heat pump system of a laundry treatment apparatus having a single duct of relatively small volume in which the refrigerant flows and a large total heat exchange surface; the evaporator, the production costs of which are thus kept low (since the evaporator does not use customized fins), allows the use of flammable refrigerants with very low Global Warming Potential (GWP), such as, for example, propane (R290) or propylene (R1270), in heat pump systems, thereby meeting the regulatory requirements relating to flammable refrigerant charging and at the same time maintaining high energy efficiency.