Tumble drier with cyclone filter

Abstract

A dryer, in particular a household tumble dryer or a household washer-dryer, comprises a drum (1) for holding textiles and a heat pump with a condenser (3) and an evaporator (2). The dryer further comprises an air circulation system (6) for circulating an airflow through the drum (1), the condenser (3), and the evaporator (2) to dry the textiles in the drum (1). A lint filter is also provided, which filters lint from the airflow. The lint filter is designed as a cyclone filter (8).

Description

Field of invention

[0001] The invention relates to a dryer, in particular a household clothes dryer or a household washer-dryer. The dryer comprises a drum, a heat pump, and an air circulation system. The heat pump comprises a condenser and an evaporator. An airflow circulates through the air circulation system, through the drum, the condenser, and the evaporator. The dryer includes a lint filter, which filters lint from the airflow. background

[0002] Tumble dryers and washer-dryers dry textiles using an airflow. During drying, the airflow carries away not only moisture but also lint from the textiles. This lint enters the air circulation system and can contaminate the condenser and evaporator. For this reason, it is standard practice to install a lint filter, in the form of a screen, downstream of the drum to filter the lint from the airflow.

[0003] With this type of design, it is recommended that the user clean the lint filter after each drying cycle. The more lint adheres to the lint filter, the greater its flow resistance. High flow resistance negatively impacts the dryer's energy consumption. However, regular cleaning of the lint filter results in significant maintenance.

[0004] DE 10 2017 11661 discloses a tumble dryer with a tangential cyclone filter. Lint collects on the water-wetted walls of the cyclone filter and falls as lint balls into a collection container.

[0005] US 2013008049 discloses a cyclone filter into which condensate water is injected.

[0006] KR 101 948 918 shows a tumble dryer which has two cyclone filters connected in parallel.

[0007] DE 10 2014 118861 shows a tumble dryer which does without a lint filter because the evaporator is washed. Description of the invention

[0008] The challenge is to reduce the maintenance requirements of a dryer.

[0009] This problem is solved by the subject matter of the independent claim. Accordingly, a dryer, in particular a clothes dryer or a washer-dryer, comprises a drum for holding textiles and a heat pump with a condenser and an evaporator. Furthermore, the dryer comprises an air circulation system for circulating an airflow through the drum, through the condenser, and through the evaporator. The evaporator extracts heat from the airflow, allowing the moisture to condense from the air and the condensate to be drained away. The condenser adds heat back to the airflow, so that warm and dry air returns to the drum.

[0010] The dryer includes a lint filter that filters lint from the airflow. The lint filter is designed as a cyclone filter.

[0011] A cyclone filter uses centrifugal forces as a separation method, generated by creating a vortex flow. In a cyclone filter, the air, which carries the lint to be separated, is set into a rotational motion by its own flow velocity through the appropriately designed stationary separator, whereas in a centrifuge, the necessary kinetic energy is transferred to the medium to be separated by the rotational movement of the container.

[0012] Using a cyclone filter as a lint filter has the advantage that the lint is filtered into a container that only needs to be emptied at longer intervals. Regular cleaning of a lint screen is eliminated. The dryer's maintenance requirements are reduced.

[0013] The lint filter is designed as an axial cyclone separator. In particular, guide vanes generate the swirl of the airflow. The separated particles then pass through an annular gap between the separator wall and the immersion tube into a collection container.

[0014] The lint filter designed as an axial cyclone separator has the advantage that it requires relatively little installation space, especially in relation to a tangential cyclone separator, and also has low airflow resistance.

[0015] In particular, the cyclone filter, designed as an axial cyclone separator, has a maximum diameter of 100 mm, specifically 80 mm, and specifically 70 mm. Axial cyclone separators with these dimensions can be easily installed in a user door of the dryer or in the base area of ​​the dryer. The user door closes the loading opening through which the user can place textiles into the drum.

[0016] In an alternative embodiment, which is not part of the invention, the cyclone filter could be designed as a tangential cyclone separator. In particular, the cyclone filter designed as a tangential cyclone separator includes an inlet shaped such that the airflow entering the cyclone filter is blown in tangentially and directed onto a circular path. Specifically, the airflow flows through a tapered cone. Due to the tapering, the rotational speed of the airflow increases, so that the lint is flung against the cone walls by centrifugal force and slowed down sufficiently to detach from the flow and trickle downwards into the collection container. The filtered air flows upwards through a centrally located pipe.

[0017] A cyclone filter designed as a tangential cyclone separator has the advantage of a very high separation efficiency.

[0018] In particular, a rectifier is arranged in the outlet channel of the cyclone filter to reduce rotational movement of the airflow at the outlet.

[0019] In particular, the cyclone filter, designed as a tangential cyclone separator, would have a guide plate arranged and designed in such a way that it directs the airflow within the cyclone filter in such a manner that, after one rotation within the cyclone filter, the airflow does not collide with the airflow entering the cyclone filter. This has the advantage of reducing the pressure loss of the airflow within the cyclone filter.

[0020] Advantageously, the dryer has at least two, in particular at least four, and especially at least six, cyclone filters. These cyclone filters are arranged parallel to each other in terms of airflow, meaning that an air molecule flows through only one of the multiple cyclone filters in a single cycle. The parallel arrangement of several cyclone filters has the advantage that they can be housed in a relatively small installation space, for example, in the user door or in the base of the dryer.

[0021] The cyclone filter is advantageously located inside the user door. In particular, the filtered air flows vertically downwards out of the user door. This placement of the cyclone filter in the user door allows the user to easily empty the cyclone filter's collection container(s).

[0022] In particular, the cyclone filter is located below the drum, especially in a base area of ​​the dryer.

[0023] The cyclone filter advantageously features a collection container for gathering the separated lint. This collection container is a flow-impeded dead end, meaning there is no continuous airflow into it. Only the filtered lint is separated or flung into the collection container.

[0024] In particular, the collection container can be emptied and cleaned. Alternatively, a rinsing system can be provided which automatically rinses the collection container using fresh water or condensate. The lint then enters the wastewater system.

[0025] A cyclone filter is not perfect; that is, it does not have a 100% separation efficiency. In particular, it only partially filters airborne particles from the air. For this reason, it is advantageous to use a screen filter in the dryer, which requires less frequent maintenance. Specifically, the screen filter is located downstream of the cyclone filter and upstream of the evaporator in the air circulation system. The screen filter can be a HEPA filter.

[0026] In a particular embodiment, the airflow between the cyclone filter and the screen filter intersects the airflow between the drum and the cyclone filter. When the word "between" is used, the first component is meant upstream and the second component downstream. For example, the airflow between the cyclone filter and the screen filter is that section of the air circulation system which terminates upstream at the cyclone filter and downstream at the screen filter.

[0027] In other words, within the filter unit, the airflow upstream of the cyclone filter crosses with the airflow downstream of the cyclone filter.

[0028] In particular, the sieve filter and the air circulation system are designed such that the airflow between the drum and the cyclone filter tears away lint adhering to the sieve filter and moves it into the cyclone filter. This design has the advantage that the sieve filter does not need to be cleaned by the user, or only needs to be cleaned irregularly.

[0029] It is advantageous if no further lint filter is arranged downstream of the drum and upstream of the cyclone filter. Only the cyclone filter, or optionally the sieve filter, is present. Brief description of the drawings

[0030] Further embodiments, advantages, and applications of the invention will become apparent from the dependent claims and from the following description with reference to the figures. These figures show: Fig. 1 shows a diagram of a clothes dryer with four cyclone filters connected in parallel; Fig. 2 a cyclone filter designed as an axial cyclone separator; Fig. 3 a cyclone filter designed as a tangential cyclone separator, this embodiment of which is not part of the invention; and Fig. 4 a special arrangement of cyclone filter and sieve filter. Ways to implement the invention

[0031] The Fig. 1 Figure 1 shows a diagram of the main technical components of a clothes dryer. The clothes dryer includes a drum 1 in which textiles can be loaded and dried. It also includes a heat pump with the components evaporator 2, condenser 3, compressor 4, and expansion valve 5. An airflow circulates in an air circulation system 6. Furthermore, the clothes dryer includes a filter unit 7 with four cyclone filters 8 connected in parallel and a sieve filter 9.

[0032] The warm airflow passes through drum 1 and extracts moisture from the textiles, thus drying them. The airflow also picks up lint, which is removed from the textiles in the drum. The airflow, now enriched with lint and moisture, leaves drum 1 and flows through the air circulation system 6 to the filter unit 7.

[0033] Filter unit 7 is designed to filter lint from the airflow. Without filtration, the lint would settle on the evaporator 2 and the condenser 3, impairing their function.

[0034] The filter unit 7 is preferably located in the user door through which the user accesses the drum. Alternatively, the filter unit can also be located in the base of the tumble dryer, i.e., below the drum.

[0035] According to the invention, the filter unit 7 comprises four cyclone filters 8 connected in parallel. These cyclone filters 8 can be configured as axial separators or, not according to the invention, as tangential separators. These two types of cyclone filters are described by reference to the Figs. 2 and 3 even more detailed description.

[0036] Downstream of the cyclone filters 8, the filter unit 7 additionally includes a sieve filter 9. This is provided because the cyclone filters 8 do not have a separation efficiency of 100%. Small amounts of lint or lighter suspended particles that are not filtered by the cyclone filters 8 are to be captured by the sieve filter 9.

[0037] The airflow, now free of lint, leaves the filter unit 7 through the air circulation system 6 and enters the evaporator 2 downstream. The evaporator 2 cools the airflow, causing the moist air to condense and the condensate to be collected. A collection container (not shown) gathers the condensate.

[0038] The cooled and dried airflow then flows to the condenser 3 located further downstream. The condenser 3 adds heat to the airflow to bring it up to drying temperature.

[0039] Further downstream, a blower 10 is also located. The blower propels the airflow through the air circulation system 6 and through the aforementioned components of the tumble dryer. Finally, the airflow returns to the drum 1. The cycle then begins again with the drying of the textiles placed in the drum 1.

[0040] As mentioned, the cyclone filters 8 are designed as axial cyclone separators. Fig. 2 Figure 1 schematically shows such an axial cyclone separator. The airflow enters the axial cyclone separator from the left. Guide vanes 11 impart a swirling motion to the airflow. This swirling motion is generated by the movement of the airflow along the guide vanes 11. The guide vanes 11 themselves do not move. Centrifugal forces fling the lint carried by the airflow against the separator walls 12 and move them into the annular gap 13 between the separator walls 12 and the dip tube 14. The lint thus enters the collection container 15. The direction of movement of the lint is indicated by the arrows 16.

[0041] The collection container 15 is sealed at the rear. This means that there is no constant airflow into or out of the collection container 15. Only the lint is flung into the collection container 15 by centrifugal force.

[0042] The lint-free, cleaned airflow exits the axial cyclone separator through the centrally located immersion tube 16. This outlet flow is marked with arrow 17. The diameter D of the axial cyclone separator is, for example, 60 mm.

[0043] As mentioned, the cyclone filter can also be designed as a tangential cyclone separator. One such embodiment is described in Fig. 3 shown.

[0044] The airflow enters the tangential cyclone separator through an inlet 18. The direction of inflow is indicated by arrow 19. The inlet 18 is shaped and arranged such that the airflow entering the cyclone filter is blown in tangentially and guided onto a circular path. The airflow flows downwards and is further accelerated by a tapered cone 20. Centrifugal forces fling the lint against the cone walls. This slows the lint sufficiently to detach it from the flow and trickle downwards into the collection container 21. The direction of movement of the lint is indicated by arrow 22. The filtered air flows upwards through the centrally located dip tube 23 and exits the tangential cyclone separator.

[0045] The tangential cyclone separator can include a guide plate 24 which directs the airflow in such a way that, after one revolution within the tangential cyclone separator, it flows below the inlet 19 and therefore does not collide with the air flowing in through the inlet 19.

[0046] Furthermore, the tangential cyclone separator can include a rectifier 25 to reduce the rotational motion of the airflow through the immersion tube 23. Such a rectifier can also be incorporated into an axial cyclone separator, as in Fig. 2 shown, used.

[0047] The Fig. 4Figure 1 shows a specific arrangement of a cyclone filter 8 and a screen filter 9. Air flows from the drum into the filter unit 7, as indicated by arrows 26. The airflow passes the screen filter 9 and enters the cyclone filter 8. Lint is separated into the collection container 21, and the filtered air flows out of the cyclone filter 8 through the dip tube 23. The outgoing air crosses the incoming airflow 26 at point 27, then flows through the screen filter 9 and exits the filter assembly 7 through the opening 28 towards the evaporator.

[0048] The screen filter 9 retains lint or other particles that were not filtered from the airflow by the cyclone filter 8. To avoid the need for regular cleaning of the screen filter 9 by the user, the filter unit 7 is designed such that the air flowing into the filter unit 7 is drawn away from the screen filter 9 on its way to the cyclone filter 8 and transported back into the cyclone filter 8. This increases the likelihood that the lint and particles in the cyclone filter will ultimately be separated into the collection container 21.

[0049] While preferred embodiments of the invention are described in the present application, it should be clearly pointed out that the invention is not limited to these and can also be carried out in other ways within the scope of the following claims.

Claims

1. Dryer, in particular a household laundry dryer or a household washer-dryer, comprising - a drum (1) for holding textiles, - a heat pump with a condenser (3) and with an evaporator (2), - an air circulation system (6) for circulating an air flow through the drum (1), the condenser (3) and the evaporator (2) for drying the textiles in the drum (1), - a lint filter for filtering lint from the air flow, wherein the lint filter is a cyclone filter (8), characterised in that the cyclone filter (8) is an axial cyclone separator.

2. Dryer according to claim 1, wherein the cyclone filter (8) has a maximum diameter (D) of 100 mm, in particular 80 mm, in particular 70 mm.

3. Dryer according to one of the preceding claims, wherein a rectifier (25) is arranged in an outlet duct (14, 23) of the cyclone filter (8) in order to reduce a rotational movement of the air flow.

4. Dryer according to one of the preceding claims, comprising at least two, in particular at least four, in particular at least six, cyclone filters (8), which are arranged parallel to one another in terms of flow.

5. Dryer according to one of the preceding claims, comprising a user door, wherein the cyclone filter (8) is arranged inside the user door.

6. Dryer according to claim 5, wherein the cyclone filter (8) is arranged such that the filtered air exits vertically downwards from the user door.

7. Dryer according to any one of claims 1 to 4, wherein the cyclone filter (8) is arranged below the drum (1).

8. Dryer according to one of the preceding claims, wherein the cyclone filter (8) comprises a collecting container (15, 21) for collecting the separated lint, wherein the collecting container (15, 21) is a dead end in terms of flow.

9. Dryer according to claim 8, wherein the collecting container (15, 21) is adapted in such a way that - it can be emptied and cleaned by the user, and / or - can be automatically rinsed out by a rinsing system, wherein the rinsing system uses either fresh water or condensate water separated from the evaporator.

10. Dryer according to one of the preceding claims, wherein the dryer has a sieve filter (9) which is arranged in the air circulation system (6) between the cyclone filter (8) and the evaporator (2), in particular wherein the sieve filter (9) is a suspended matter filter.

11. Dryer according to claim 10, wherein the air flow between the cyclone filter (8) and the sieve filter (9) crosses the air flow between the drum (1) and the cyclone filter (8).

12. Dryer according to claim 13, wherein the screen filter (9) and the air circulation system (6) are adapted in such a way that the air flow between the drum (1) and the cyclone filter (8) moves lint adhering to the screen filter (9) into the cyclone filter (8).

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