CN117587622A

CN117587622A - Method for operating a drying appliance having a heat pump and a cleaning device

Info

Publication number: CN117587622A
Application number: CN202311023905.6A
Authority: CN
Inventors: M·希曼斯基; M·安杰伊扎克
Original assignee: BSH Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2022-08-17
Filing date: 2023-08-15
Publication date: 2024-02-23
Also published as: EP4324977A1

Abstract

The invention relates to a method of operating a drying apparatus comprising: a roller; a heat pump; a blower; and a cleaning device, the method comprising the following steps in a drying phase in which the drum is at least temporarily rotated, the blower being turned on: (a) Determining whether a predetermined minimum amount of water-based cleaning liquid is present in the cleaning device; (b1) Shutting down the compressor when a minimum amount of water-based cleaning liquid is present in the cleaning device; (b2) Skipping the following steps (c) and (d) when there is no minimum amount of water-based cleaning liquid in the cleaning device; (c) Activating the cleaning device to cause the water-based cleaning solution to be delivered into the first heat exchanger; (d) Pumping the condensed water into the cleaning device by means of a pump until at least a minimum amount of water-based cleaning liquid is again present in the cleaning device; (e) repeating steps (c) and (d) at least once.

Description

Method for operating a drying appliance having a heat pump and a cleaning device

Technical Field

The invention relates to a method for operating a drying appliance having a heat pump and a cleaning device. The invention relates in particular to a method of operating a drying apparatus comprising: a drum for receiving laundry; a heat pump having an evaporator as a first heat exchanger and a condenser as a second heat exchanger, which are arranged in the process air line at a distance from the flow direction, the heat pump also having a compressor and an expansion valve; a blower disposed in the process air conduit; and a cleaning device for cleaning the first heat exchanger with an aqueous cleaning liquid (W).

Background

A known condensation dryer has a drum rotatably mounted in a housing and a fan for generating a process air flow intended to flow through the drum and through a condensation device comprising a collecting container for collecting condensed water accumulated during drying, and furthermore a condensation tank connected to the collecting container by a pipe, which is arranged in a tank connected to the collecting container by a drain. In this case, the condensate in the collecting vessel is usually fed to the condensate tank by means of a pump. The condensate tank is located in a trough having a drain opening to a collection vessel.

Household appliances having a cleaning device for a heat exchanger are known.

Publication WO 2017/0325550 A1 describes a household appliance having: a first heat exchanger and a second heat exchanger arranged in the process air duct at a distance from each other with respect to the flow direction of the process air duct; and a cleaning device for cleaning the first heat exchanger by means of a cleaning liquid (W), wherein a flow guiding structure is present in the process air duct between the first heat exchanger and the second heat exchanger, which flow guiding structure has at least one planar flow guiding element which is oriented at least approximately horizontally between the first heat exchanger and the second heat exchanger, wherein the at least one flow guiding element is arranged above the bottom of the flow guiding structure. The household appliance is in particular a clothes drying appliance with a heat pump.

Disclosure of Invention

In view of this situation, it is an object of the present invention to provide an improved method of operating a drying apparatus with a heat pump. Preferably, the overall operating efficiency of the dryer should be improved, i.e. an improved method is provided for cleaning the heat exchanger of the heat pump, in particular the heat exchanger arranged in the process air circuit, which is arranged after the directly cleanable heat exchanger.

According to the invention, this object is achieved by a method of operating a drying apparatus having a heat pump and a cleaning device for a heat exchanger according to the independent claim. Preferred embodiments of the method according to the invention are particularly shown in the dependent claims.

Accordingly, the present invention relates to a method of operating a drying apparatus comprising: a drum for receiving laundry; a heat pump having an evaporator as a first heat exchanger and a condenser as a second heat exchanger, which are arranged in the process air line at a distance from the flow direction; a compressor and an expansion valve; a blower disposed in the process air conduit; and a cleaning device for cleaning the first heat exchanger with a water-based cleaning liquid W, the method comprising the following steps in a drying phase in which the drum is at least temporarily rotated, the blower being turned on:

(a) Determining whether a predetermined minimum amount of M is present in the cleaning device _min Is a water-based cleaning liquid W;

(b1) When there is a minimum amount of M in the cleaning device _min Shutting down the compressor when the water-based cleaning solution W is present;

(b2) When there is no minimum amount of M in the cleaning device _min Is a water-based cleaning solution of (2)When W, skipping the following steps (c), (c 1), (c 2) and (d);

(c) Activating the cleaning device such that a water-based cleaning liquid W is delivered into the first heat exchanger, wherein during delivery of the water-based cleaning liquid:

(c1) In the case that the water content H of the clothes is higher than the predetermined water content H _AT At a power P sufficient to transfer at least a portion of the aqueous cleaning liquid W from the first heat exchanger to the second heat exchanger ₁ Operating the blower 7; and

(c2) In the case where the water content H of the laundry is lower than the predetermined water content H _CD In the case of (1), wherein H _AT >H _CD At less than power P ₁ Power P of (2) ₂ Operating the blower and interrupting the rotation of the drum, the power P ₂ Insufficient to transfer at least a portion of the aqueous-based cleaning liquid W from the first heat exchanger to the second heat exchanger;

(d) Drawing condensed water into the cleaning device by means of a pump, preferably from a condensed water tray in the bottom assembly, until at least a minimum amount of water-based cleaning liquid W is again present in the cleaning device, wherein in case (c 2) the rotation of the drum is resumed after the cleaning device has stopped working, before pumping;

(e) Repeating steps (c) and (d) at least once; and then

(f) Restarting the compressor in case of (c 1); and

(g) In the case of (c 2), when the temperature in the drum reaches a predetermined limit T _lim And flushing the first heat exchanger.

In a preferred embodiment of the method according to the invention, steps (c 1) and (d) are repeated a predetermined number of times n _set1 Preferably two times, more preferably three times.

In a preferred embodiment of the method according to the invention, step (b 2) may be repeated a predetermined number of times n _set2 . After reaching the predetermined number n _set In the case of (a), the drying apparatus will be used to the drying apparatusThe user indicates, in particular shows, a separate cleaning request.

In a preferred embodiment of the method according to the invention, the predetermined operating time t is reached if and only if _set In this case, steps (a), (b 1), (b 2) and (c 1) may be performed.

In a particularly preferred embodiment of the method according to the invention, a flow guiding structure is present in the process air duct between the first heat exchanger and the second heat exchanger, which flow guiding structure has at least one planar flow guiding element which is arranged at least approximately horizontally between the first heat exchanger and the second heat exchanger and which is arranged above the bottom of the process air duct.

In this method, the at least one flow guiding element is preferably strip-shaped, which extends transversely to the process air duct with respect to its longitudinal extension.

Preferably, for the method of the present invention, the first heat exchanger, the second heat exchanger and the flow directing structure have the same flow width.

In a particularly preferred embodiment of the method according to the invention:

the flow guiding structure is a grid-shaped flow guiding structure, which is provided with at least two circumferentially closed air guiding channels arranged up and down;

the air guide channels are separated from one another by a common air guide element;

the first open end face of the air guide channel faces the air outlet side of the first heat exchanger; and

the second open end face of the air guide channel faces the air inlet side of the second heat exchanger.

In a preferred embodiment of the method according to the invention, the flow guiding structure has at least two arrangements arranged next to each other, each arrangement comprising at least two circumferentially closed air guiding channels arranged one above the other.

In a preferred embodiment of the method according to the invention, in the drying apparatus, the first heat exchanger and the second heat exchanger are arranged on a common base, and the flow guiding structure may be inserted as a preform between the first heat exchanger and the second heat exchanger.

In the method according to the invention, the measurement of the moisture content H of the laundry is preferably performed by means of a conductivity sensor arranged in the drum.

In the method according to the invention, the determination of the amount of water M in the cleaning device is more preferably performed by means of a water level sensor and/or a counter for the pumping operation of the pump.

The drying apparatus includes a heat pump. Thus, the drying apparatus generally includes a heat pump circuit including a refrigerant passage for circulating a refrigerant, a condenser as a heat source, an evaporator as a heat sink, an expansion device for expanding the refrigerant, and a compressor for driving and compressing the refrigerant, the refrigerant being circulated through the compressor, the condenser, the expansion device, and the evaporator in this order. The condenser serves to heat the process air stream before it enters the drum as a drying chamber, while the evaporator serves to cool the air stream after it leaves the drying chamber.

In an embodiment, the drying apparatus used has a flow guiding element, which has the advantage that the flow guiding element may reduce or even partly prevent the entrained water from sinking between the two heat exchangers, whereby the second heat exchanger may be cleaned to a higher level by the entrained water than without the flow guiding structure. That is, the deflector element can cause the water droplets approaching or falling from above to experience a higher reaction force in the region of the deflector element due to dynamic pressure than when freely falling, thereby increasing the range of the water droplets in the horizontal direction. In addition, the water droplets settle on the flow guiding element and can create a water film there, which is pressed by the process air flowing in the direction of the second heat exchanger. At the free edge of the flow guiding element facing the second heat exchanger, water can be separated from the flow guiding element to be brought back to the second heat exchanger by the process air. Thus, the impact height on the second heat exchanger can be improved by adjusting the position of the flow guiding element. The cleaning means may comprise, for example, a nozzle or a downspout which may be pressurized with cleaning liquid. The cleaning liquid is typically an aqueous solution, such as water. In particular, the cleaning liquid may comprise or be fresh water and/or condensed water. The water may have additives such as cleaning agents.

The at least approximately horizontally oriented flow guiding element may in particular be a planar element oriented horizontally or substantially horizontally in the direction from the evaporator to the condenser. A substantially horizontal orientation is understood to mean a deviation from the horizontal by no more than 45 °, i.e. no more than +45° or-45 °. In particular, the direction may be measured between the end points of the flow guiding element.

The optional at least one flow guiding element is preferably arranged above the bottom of the process air duct, which in particular includes that it is arranged spaced apart from said bottom. Thus, there is a flow cross section of the process air between the bottom of the process air duct and the flow guiding element (between the bottom and the lowest flow guiding element adjacent thereto in case a plurality of flow guiding elements are arranged at a distance from each other).

The flow directing structure may be a separately manufactured component that may be inserted as a section of the process air conduit or may be an insert of the process air conduit.

The bottom of the flow directing structure may match the bottom of the process air duct at that portion. Alternatively, the bottom of the flow directing structure may be spaced apart from the bottom of the process air conduit. Likewise, the top of the flow directing structure may be matched to the top of the process air duct at that portion. Alternatively, the top of the flow guiding structure may be spaced apart from, in particular below, the top of the process air pipe.

In a preferred embodiment, it is advantageous in terms of efficient, low-loss flow guiding, the flow guiding element having a smooth, in particular planar or simply curved surface. In this way, flow resistance and water deposition on the flow guiding element can be effectively avoided.

For example, the flow guiding element may be made of metal or plastic. The metal may be stainless metal and/or have an anti-corrosion coating. The flow guiding element may be assembled from a plurality of separate parts, for example sheet metal parts, or may be a single part, for example as an injection molded part of a single plastic.

The drying apparatus used in the method according to the invention may be a stand-alone dryer or a washer-dryer. The process air duct may be a closed process air duct ("circulating air dryer") or an open process air duct ("exhaust dryer").

In a further embodiment of the method according to the invention, the at least one flow guiding element is designed as a strip or strip, which extends in particular transversely to the process air duct with respect to its longitudinal extension. This makes it possible to influence the movement of the air flow and water over a large width, in particular the full width, of the process air duct particularly easy to implement. In particular, the flow guiding element may be formed as a straight, planar strip of material.

According to the invention, it is preferred that the at least one flow guiding element extends substantially over the entire width of the process air duct in the drying apparatus used. Here, "substantially the entire width" is understood to mean in particular the entire width or at least 90% of the entire width. This effectively suppresses the swirling airflow which may flow laterally past the flow guiding element to reduce the cleaning effect of the second heat exchanger.

In another embodiment, the first heat exchanger, the second heat exchanger and the flow guiding structure preferably used in the drying apparatus have the same flow width. In this way, a particularly uniform flow can be achieved. The flow width is to be understood in particular as the width of the process air duct associated with the respective one.

According to the invention, it is furthermore preferred that in one embodiment at least two flow guiding elements are arranged one above the other. In this way, the falling height of the water in the gap between the two heat exchangers can be limited particularly effectively, i.e. by the height of the flow guiding element, in particular by the height of the edge facing the second heat exchanger. Preferably, the bottom of the flow guiding structure and/or the bottom of the process air pipe represents or is another flow guiding element.

Alternatively, the bottom does not constitute a flow guiding element for distributing the water impinging the second heat exchanger.

It is further preferred that the outlet side of the first heat exchanger has a higher bottom than the inlet side of the second heat exchanger and that the edge of the at least one flow guiding element facing the first heat exchanger is higher than the edge thereof facing the second heat exchanger.

Thus, the potential flow guiding elements extend obliquely downwards in the flow direction of the process air P relative to the horizontal. Thus, the height of the water impinging the second heat exchanger may also be increased independently of the flow guiding structure. In this way, the flow guiding structure can be designed more simply and effectively.

The first heat exchanger may be at the same level as the second heat exchanger, may be higher than the second heat exchanger, or may be lower than the second heat exchanger. In a preferred embodiment of the method, the first heat exchanger is lower in height than the second heat exchanger. This allows the mounting heights of the two heat exchangers to be at least approximately equal.

In the method according to the invention, it is more preferred that the upper sides of the first and second heat exchangers used are flush with each other, in particular occupy the same height plane.

Finally, in a preferred embodiment of the method a flow guiding structure is used, which has a bottom and a top, between which at least one flow guiding element is arranged, in particular oriented horizontally sideways. This results in a particularly compact and efficient arrangement. In order to distribute the water impinging the second heat exchanger particularly effectively, a plurality of flow guiding elements may be arranged between the bottom and the top. The distance between the plurality of flow guiding elements and/or between the bottom and/or the top may be equal or different. The bottom and/or the top may be designed as further flow guiding elements, but may also be structural elements without a flow guiding function for distributing the water impinging on the second heat exchanger (but possibly for the flow guiding of the process air).

If a flow guiding structure is used, this is preferably a grid-like flow guiding structure having at least two circumferentially closed air guiding channels arranged one above the other, which air guiding channels are separated from each other by flow guiding elements. This results in a particularly compact arrangement. In this preferred embodiment, the at least one flow guiding element thus represents in particular the bottom of the upper air guiding channel and the top of the lower air guiding channel. The flow directing element may be spaced apart from the bottom of the process air conduit or may be disposed above the bottom thereof.

It is also advantageous if the first open end face of the at least one air guide channel faces the air outlet side of the first heat exchanger and the second open end face of the at least one air guide channel faces the air inlet side of the second heat exchanger. This has the advantage that a particularly straight air guide channel can be realized between the two heat exchangers.

According to the method of the invention, it is particularly advantageous if the optional but preferably used flow guiding structure, in particular the first open side thereof, is directly adjacent to or spaced apart from the outlet side of the first heat exchanger, in particular at a distance of not more than 10mm, in particular not more than 5mm. Such a distance facilitates the insertion of the flow guiding structure while effectively reducing the drop height.

It is particularly advantageous if the optional but preferably used flow guiding structure, in particular the second open side thereof, is directly adjacent to or spaced apart from the inlet side of the second heat exchanger, in particular at a distance of not more than 10mm, in particular not more than 5mm. Such a distance facilitates the insertion of the flow guiding structure while effectively reducing the drop height. The flow directing structure or the at least one flow directing element may contact the at least one heat exchanger.

In another embodiment, the flow guiding structure has at least two arrangements arranged next to each other, each arrangement comprising at least two circumferentially closed air guiding channels arranged one above the other. In this way, it is possible to suppress cross flow which increases the number of water drops falling by extending the path of the water drops. The resulting stronger air flow path also increases the air velocity, which is more effective in suppressing the occurrence of water drop.

In a further embodiment, the gas guide channels adjacent to one another are separated by a common, in particular vertical, partition. This makes the design particularly compact.

Another embodiment is that the process air duct has a rectangular cross section when seen from the flow direction. This has the advantage that the flow guiding structure can be realized by a rectangular arrangement of planar members or partial areas, which makes manufacture particularly simple and inexpensive. This applies in particular to the multipart design of the flow guiding structure.

Another embodiment is that the flow guiding structure or the air guiding channel has a basic shape like a grid, the air guiding channel being a grid opening. In a further embodiment, the first heat exchanger and the second heat exchanger are arranged on a common support, in particular a base, and the flow guiding structure can be inserted as a preform between the first heat exchanger and the second heat exchanger. This makes assembly particularly simple.

The base may be the base of a drying apparatus. For a particularly simple assembly of the drying appliance, the chassis may be a chassis as a chassis component of the drying appliance module. For example, the base assembly may be prefabricated and then inserted as a module into the drying apparatus and connected thereto.

The invention thus also provides a base assembly of a drying appliance, on which the first heat exchanger, the second heat exchanger and the flow guiding structure therebetween are arranged.

The drying apparatus may be the dryer itself, or a washer-dryer that combines a laundry washing function with a drying function.

In the present invention, a condensate collection container is used to collect condensate generated during the drying process, which condensate is pumped to the cleaning device, typically by means of an electric pump device, through a pump tube, typically a hose. For example, the condensate collection container is an open-top tray which is arranged below the condensing means, in this case the evaporator of the heat pump, so that it can collect condensate produced in the evaporator.

The water in the condensate collection container is conveyed into a cleaning device, which is preferably arranged in the upper part of the drying apparatus.

The drying apparatus is a front loading dryer, which means that the drum in which the laundry is located has an axis oriented in a horizontal manner or slightly inclined with respect to the horizontal plane, or a top dryer, in which the axis of the drum is substantially vertical. In a preferred embodiment, the drying appliance is a front-loading washer-dryer.

The process air circuit is in particular a closed loop circuit, comprising a process air circuit for guiding an air flow for drying laundry in the drum. The opposite ends of the process air loop are connected to the drum. More specifically, hot drying air is fed into the drying chamber, flows over the laundry, and the moist (and cooled at a lower temperature) air thus produced also flows out of the drying chamber. In the case of a closed-loop dry air circuit, the moist process air is fed into the evaporator of the heat pump, where it is further cooled and the moisture therein is condensed. The cold dry air thus produced is heated before entering the drum again through the condenser of the heat pump, and the whole cycle is repeated until the end of the drying process. However, dehumidified process air may also be discharged outside the drying apparatus.

The drying apparatus generally comprises a control unit for the operation of the drying apparatus.

The present invention provides a number of advantages. Advantages of the present invention include improving performance of a dryer by providing a drying apparatus whose maximum drying performance can be achieved over a service life due to efficient removal of laundry residues. Furthermore, in an embodiment of the present invention, since laundry residues are filtered from the air entering the heat pump condenser, maximum drying performance of the drying apparatus during the service life can be achieved. Stable drying performance can be achieved over the life of the drying apparatus.

Drawings

Fig. 1 to 4 show a non-limiting example of a drying apparatus or component, in which the method of the invention can be advantageously implemented, wherein corresponding components are identified by the same reference numerals.

Fig. 1 shows a schematic structural view of a drying apparatus, in which no flow guiding structure is present;

FIG. 2 shows a cross-sectional view of a base assembly in an oblique top view, the base assembly having a first heat exchanger, a second heat exchanger, and a flow directing structure disposed therebetween;

FIG. 3 illustrates a cross-section of the base assembly of FIG. 2 longitudinally through a heat exchanger and a flow directing structure; and

fig. 4 shows an oblique front view of a portion of a base assembly including a first heat exchanger and a flow directing structure.

Detailed Description

Fig. 1 shows a schematic diagram of a corresponding kind of drying apparatus 1. In the present embodiment, the drying apparatus has a horizontally rotatable laundry drum 2 as a receiving space for laundry to be dried, which is not shown here. During the drying process, the dry and hot process air P enters the laundry drum 2 through the process air duct 3 as an air flow duct and sweeps over the laundry in the drum. During this process, the process air P absorbs moisture. The now moist, warm process air P leaves the laundry drum 2 again and is led via the process air duct 3 to the first heat exchanger 4. The first heat exchanger 4 cools the process air P, condensing its moisture out. The heat exchanger surfaces of the first heat exchanger 4 located in the process air duct 3 are thus covered with a moisture film, from which condensation water droplets are separated and fall, for example into a collecting tray not shown here. However, the water film also adheres particulates such as lint and hair in the process air P to the heat exchanger surfaces, and even after the water film evaporates, the particulates remain adhered thereto, which reduces the efficiency of the first heat exchanger 4. In order to remove lint, hair, etc. on the first heat exchanger 4, a cleaning device 5 may be used which uses water W under high momentum as a cleaning agent to clean the heat exchanger surfaces of the first heat exchanger 4. The cleaning device 5 may for example comprise a nozzle communicating with the pump and directed towards the first heat exchanger 4. The cleaning device 5 may alternatively comprise a downpipe communicating with a reservoir, not shown here, in which the water W discharged at high speed impinges the first heat exchanger 4 from above. The downpipe may be formed with a nozzle system on the outlet side to create a more widely distributed water curtain. From the first heat exchanger 4, the now drier process air P is led to a second heat exchanger 6, which heats the process air P again. Thus, the first heat exchanger 4 and the second heat exchanger 6 are arranged spaced apart from each other with respect to the flow direction of the process air P, the first heat exchanger 4 being located at the front end of the second heat exchanger 6.

From the second heat exchanger 6, the process air P, which has now been dried and warmed, is led into the laundry drum 2 via the process air duct 3. Thus, the process air duct 3 forms a closed process air circuit with the laundry drum 2. A fan or ventilator 7 may be provided for circulating the process air P in the process air loop. From the process air P point of view, the first heat exchanger 4 acts as a condenser and the second heat exchanger 6 acts as a heater.

The first heat exchanger 4 and the second heat exchanger 6 are designed here as part of a heat pump which also has a drive in the form of a compressor 8 and an expansion valve 9. In the arrangement shown, these components 4,6,8 and 9 are connected to one another by means of a refrigerant tube 10, in which a working fluid or refrigerant K circulates. The operation of heat pumps is basically well known and need not be explained further here. From the heat pump point of view, the first heat exchanger 4 acts as an evaporator and the second heat exchanger 6 acts as a condenser.

Flock and hair are deposited mainly on the wet first heat exchanger 4, but also a small part on the second heat exchanger 6. In order to be able to clean the second heat exchanger 6 at the same time, the cleaning device 5 is operated with the fan 7 running. Thus, the water W present in the process air P in the region of the first heat exchanger 4 (for example in the form of a water curtain) is partly entrained in the process air P and reaches the second heat exchanger 6, the second heat exchanger 6 being cleaned in the region where it is impinged by the water W.

In principle, the second heat exchanger 6 may be cleaned in a process that is independent of the cleaning process of the first heat exchanger 4. For example, the fan 7 may be operated to clean the second heat exchanger 6, while not operated to clean the first heat exchanger. The cleaning of the second heat exchanger 6 may be performed during the drying process or may be performed during a separate cleaning process. For example, during operation of the fan 7, approximately 50% of the water W directed towards the first heat exchanger 4 may be diverted or diverted to the second heat exchanger 6. The position of the fan 7 in the process air duct 3 is in principle not limited. For example, in addition to being arranged between the laundry drum 2 and the first heat exchanger 4, a fan 7 may also be arranged between the second heat exchanger 6 and the laundry drum 2.

For example, if different sizes of the first heat exchanger 4 and the second heat exchanger 6 are used for technical and economical reasons, a given installation space may result in a significantly different distance between them. This may be disadvantageous because the trajectory of entrained water droplets (indicated by the dashed arrow) is increasingly influenced by their own weight, or the trajectory there is particularly dependent on their own weight, in the region between the first heat exchanger 4 and the second heat exchanger 6. Over a larger distance, the water W therefore disadvantageously reaches only the low region of the second heat exchanger 6, as shown in simplified form in fig. 1.

Fig. 2 shows a cross-section of the base assembly 12 of the drying device 1 in an oblique top view, wherein the second heat exchanger 6 is arranged spaced apart in the flow direction of the process air P after the first heat exchanger 4. The relevant sectional view is in a horizontal direction so that the top cover of the flow guiding structure 13 is cut away and is therefore not shown. Thus, the flow guiding structure 13 is shown as being open at the top.

The first heat exchanger 4 has a basic shape of a cube. The moist process air P enters from its inlet surface 4a where it is cooled and condenses out of the moisture. The process air P then flows through the flow guiding structure 13 and through the second heat exchanger 6 where it is heated. The second heat exchanger 6 also has the basic shape of a cube. The first heat exchanger 4, the second heat exchanger 6 and the flow guiding structure 13 form an air guiding channel here and have the same flow width.

After leaving the second heat exchanger 6, the process air P may be introduced into the laundry drum 2. The water entrained and used for cleaning the second heat exchanger 6 may for example drip or fall from the second heat exchanger 6 for example into a water tank.

The base assembly 12 has a common base 28 and may be preloaded with the first heat exchanger 4, the second heat exchanger 6 and the flow guiding structure 13 and then installed as a bottom side module in the heat pump dryer 1. In particular, the flow guiding structure 13 may act as a preform between the first heat exchanger and the second heat exchanger, in particular it may be interposed between the first heat exchanger and the second heat exchanger.

Fig. 3 shows a section of the foundation assembly of fig. 2 longitudinally through the heat exchangers 4,6 and the flow guiding structure 13. The section here corresponds to a vertical plane.

The first heat exchanger 4, the second heat exchanger 6 and the flow guiding structure 13 extend at least approximately to the same height, their tops being at least approximately flush with each other. Further, since the first heat exchanger 4 is lower in height than the second heat exchanger 6, the lower surface of the first heat exchanger 4 is higher than the lower surface of the second heat exchanger 6. Thus, the outlet surface 4b of the first heat exchanger 4 also has a higher lower surface or higher lower edge than the inlet surface 6a of the second heat exchanger 6.

Fig. 4 shows an oblique front view of a portion of the bottom assembly 12 comprising the first heat exchanger 4 and the flow guiding structure 13, while the second heat exchanger 6 is not shown. This provides an air-out side view of the flow guiding structure 13.

Referring to fig. 3 and 4, the flow guiding structure 13 used in one embodiment of the process according to the invention shows two flat flow guiding elements 14 in the form of strips or bars, which are arranged at least approximately horizontally between the first heat exchanger 4 and the second heat exchanger 6. The flow guiding element 14 thus extends transversely to the process air duct with respect to its longitudinal extension or is mounted transversely in the process air duct. The flow guiding elements 14 are arranged one above the other and they are inclined 5 ° to 10 ° downwards in the flow direction relative to the horizontal direction but not in the transverse direction. The edge of the flow guiding element 14 facing the first heat exchanger 4 is thus higher than its corresponding edge facing the second heat exchanger 6. Above the two flow guiding elements 14 there is a horizontally arranged top 15, below which is a bottom 16, which in the flow direction is inclined towards the horizontal or downwards. The top 15 and bottom 16 are also substantially strip-shaped or strip-shaped. The bottom 16 may also be considered as a flow guiding element. The top 15 and/or bottom 16 may be manufactured as one piece with the flow guiding element 14 and the side wall 17, but may alternatively be manufactured separately from the flow guiding element 14 and the side wall 17.

As shown in fig. 4, the two flow directing elements 14, the top and the bottom 16 are laterally defined by a common, vertically oriented side wall 17. At the two guide elements 14 and the top 15 a vertically arranged partition 18 is also centrally inserted. Due to this design, the flow guiding structure 13 has five lateral and circumferentially closed air guiding channels 19a,19b,20a,20b and 21. Two air guide channels 19a and 20a arranged side by side are formed by the upper flow guiding element 14, the top 15, the partition 18 and the respective side walls 17. Two side-by-side air guide channels 19b and 20b are formed by the two guide elements 14, the partition 18 and the respective side walls 17. The air guide channel 21 is formed by the bottom 16, the lower guide element 14 and the two side walls 17, and has twice the width of the air guide channels 19a,19b,20a and 20 b. The air guide passages 19a,19b, and 21 and the air guide passages 20a,20b, and 21 are arranged up and down. The air guide passages 19a,19b and 21, and 20a,20b and 21 are separated from each other by the upper and lower air guide members 14 and 14, respectively. At least the air guide channels 19a,19b,20a and 20b are arranged in a grid shape with respect to each other.

The first open side 24 of the flow guiding structure 13 facing the first heat exchanger 4 (comprising the respective first open end faces of the air guiding channels 19a,19b,20a,20b, 21) may be directly adjacent to, in contact with and/or spaced apart from (advantageously not exceeding 10mm from) the air outlet surface 4b of the first heat exchanger 4. The first open side 24 of the flow guiding structure 13 may cover the entire air outlet surface 4b or only a part thereof. The second open side 26 of the flow guiding structure 13 facing the second heat exchanger 6, including the respective second open end faces of the air guiding channels 19a,19b,20a,20b,21, may be directly adjacent to, in contact with and/or spaced apart from (advantageously not exceeding 10mm from) the air inlet surface 6a of the second heat exchanger 6. The second open side 26 of the flow guiding structure 13 may completely or only partly cover the air inlet surface 6b. An advantageous result of the provision of the flow guiding structure 13 is that, by means of the flow guiding element 14 and the optional bottom 16, the sinking of the water W entrained by the process air P between the two heat exchangers 4,6 can be reduced or even partly prevented, so that the second heat exchanger 6 can be cleaned at a higher level by the entrained water W than without the flow guiding structure 13. That is, the deflector element 14 and the possible bottom 16 may cause water droplets approaching or falling from above to experience a higher reaction force in the region of the deflector element 14 and the possible bottom 16 than in the free fall due to dynamic pressure or the like, so that the extent of the water droplets in the horizontal direction or flow direction increases. In addition, the effect that occurs is that water droplets can settle on the flow guiding element 14 and possibly the bottom 16 and form there a water film which is pressed by the process air P flowing in the direction of the second heat exchanger 6. At the free edge of the flow guiding element 14 and possibly of the bottom 16 facing the second heat exchanger 6, the water W can be separated or broken off and brought to the second heat exchanger 6 by the process air P. The impact height of the water W on the second heat exchanger 6 can thus also be improved and relatively accurately adjusted by adjusting the position of the flow guiding element 14 and optionally the bottom 16. Outside the side wall 17 of the guide structure 13, a holding lug 22 and a plug element 23 for fixing the guide structure 13 are provided.

The flow guiding structure 13 can be inserted in particular from above into the space between the two heat exchangers 4 and 6, for example by means of the plug element 23. The flow guiding structure 13 or the two flow guiding elements 14, the top 15, the bottom 16 and the two side walls 17 may be manufactured as one piece, for example as injection molded parts made of plastic. However, they may also be assembled from a plurality of parts, for example from a plurality of sheet metal parts. The cleaning of the second heat exchanger 6 may be performed during the drying process or outside the drying process.

List of reference numerals

1, a heat pump type clothes dryer; drying equipment

2, a roller; washing drum

3 process air duct

4a first heat exchanger; evaporator of heat pump

4a air inlet surface of the first heat exchanger

4b air outlet surface of first heat exchanger

5 cleaning device

6a second heat exchanger; condenser of heat pump

6a air inlet surface of the second heat exchanger

7 fan

8 compressor

9 expansion valve

10 refrigerant pipe

12 base assembly

13 flow guiding structure

14 flow guiding element

15 top part

16 bottom part

17 side wall

18 partition board

19a air guide channel

19b air guide channel

20a air guide channel

21 air guide channel

22 holding lugs

23 plug element

24 first open side of the flow guiding structure

26 second open side of the flow guiding structure

28 base

K refrigerant

P process air

W water

Claims

1. A method of operating a drying apparatus (1), the drying apparatus comprising: a drum (2) for receiving laundry; a heat pump (4, 6,8, 9) having an evaporator as a first heat exchanger (4) and a condenser as a second heat exchanger (6), which are arranged in the process air line (3) at a distance from one another with respect to the flow direction, and having a compressor (8) and an expansion valve (9); -a blower (7) arranged in the process air pipe (3); and a cleaning device (5) for cleaning the first heat exchanger (4) with a water-based cleaning liquid (W), the method comprising the following steps in a drying phase in which the drum (2) is at least temporarily rotated, the blower (7) being turned on:

(a) Determining whether a predetermined minimum amount of M is present in the cleaning device (5) _min Is used for cleaning the water-based cleaning liquid (W);

(b1) When there is a minimum amount of M in the cleaning device (5) _min Is shut down when the compressor (8) is turned off;

(b2) When there is no minimum amount of M in the cleaning device (5) _min When the water-based cleaning solution (W) is used, skipSteps (c), (c 1), (c 2) and (d) below;

(c) Activating the cleaning device (5) such that a water-based cleaning liquid (W) is fed into the first heat exchanger (4), wherein during feeding of the water-based cleaning liquid:

(c1) In the case that the water content H of the clothes is higher than the predetermined water content H _AT At a power P sufficient to convey at least a portion of the water-based cleaning liquid (W) from the first heat exchanger (4) to the second heat exchanger (6) ₁ -operating the blower (7); and

(c2) In the case where the water content H of the laundry is lower than the predetermined water content H _CD In the case of (a), wherein,

H _AT >H _CD at less than power P ₁ Power P of (2) ₂ Operating the blower (7) and interrupting the rotation of the drum (2), the power P ₂ Is insufficient to convey at least a portion of the aqueous cleaning liquid (W) from the first heat exchanger (4) to the second heat exchanger (6);

(d) The condensed water is pumped into the cleaning device (5) by means of a pump, preferably from a condensed water tray in the bottom assembly (12), until at least a minimum amount M is again present in the cleaning device (5) _min Wherein, in the case of (c 2), the rotation of the drum (2) is resumed after the cleaning device (5) has stopped working, before pumping;

(e) Repeating steps (c) and (d) at least once; and then

(f) Restarting the compressor (8) in case of (c 1); and

2. The method of claim 1, wherein steps (c 1) and (d) are repeated a predetermined number of times n _set1 。

3. Method according to claim 1 or 2, characterized in that in the drying device (1) there is a flow guiding structure (13) in the process air duct (3) between the first heat exchanger (4) and the second heat exchanger (6), which flow guiding structure (13) has at least one planar flow guiding element (14) which is arranged at least approximately horizontally between the first heat exchanger (4) and the second heat exchanger (6) and which is arranged above the bottom (16) of the process air duct (3).

4. A method according to claim 3, characterized in that the at least one flow guiding element (14) is strip-shaped and extends transversely to the process air duct (3) with respect to its longitudinal extension.

5. A method according to claim 3 or 4, characterized in that the first heat exchanger (4), the second heat exchanger (6) and the flow guiding structure (13) have the same flow width.

6. The method according to any one of claim 3 to 5, wherein,

-the flow guiding structure (13) is a grid-like flow guiding structure (13) having at least two circumferentially closed air guiding channels (19 a,19b,20a,20b, 21) arranged one above the other;

-the air guide channels (19 a,19b,20a,20b, 21) arranged one above the other are separated from each other by a common flow guiding element (14);

-a first open end face (24) of the air guide channels (19 a,19b,20a,20b, 21) facing an air outlet side (25) of the first heat exchanger (4); and

-a second open end face (26) of the air guide channels (19 a,19b,20a,20b, 21) faces an air inlet side (27) of the second heat exchanger (6).

7. The method according to claim 6, characterized in that the flow guiding structure (13) has at least two arrangements arranged next to each other, each arrangement comprising at least two circumferentially closed air guiding channels (19 a,19b,20a,20b, 21) arranged one above the other.

8. Method according to any one of the preceding claims, characterized in that in the drying apparatus (1) the first heat exchanger (4) and the second heat exchanger (6) are arranged on a common base (28), the flow guiding structure (13) being insertable as a preform between the first heat exchanger (4) and the second heat exchanger (6).

9. Method according to any one of the preceding claims, characterized in that the measurement of the water content H of the laundry is performed by means of a conductivity sensor arranged in the drum (2).

10. Method according to any of the preceding claims, characterized in that the determination of the amount of water M in the cleaning device (5) is performed by means of a water level sensor and/or a counter for the pumping operation of a pump.