EP2443985A2 - Household advice with filter assembly in drainage system - Google Patents

Abstract

The device has a filter arrangement (17) arranged at a drainage system (12) and guiding process water from a tub along a forward direction (20) in a cleaning phase and in a filter phase. The arrangement guides the process water along a rearward direction (21) in another filter phase. The filter arrangement has smaller filter effect along the forward direction than the filter effect along the rearward direction. A discharge pump (8) is operated in the former filter phase. Water level in the system is increased during the former filter phase and decreased during the latter filter phase. An independent claim is also included for a method for operating a household device.

Description

Field of the invention

The invention relates to a household appliance, in particular a dishwasher, with a tub for receiving items to be washed and with a drainage system comprising a drain pump through which process water to be discarded can be removed from the tub. The invention also relates to a method for operating such a household appliance.

background

Devices of this type, in particular in the form of dishwashers or washing machines, are known to the person skilled in the art. They serve to clean a washware in the tub in one or more cleaning phases. This may be e.g. to handle dishes in the tub of a dishwasher or laundry in the tub of a washing machine. At the end of each cleaning phase, the polluted process water is discharged via the drainage system into the sewage system.

In order to eliminate solids from the process water, devices of this type are often equipped with filters. In general, these are attached to a circulation line, with which water is conveyed from a lower region of the tub into an upper region of the tub. The solids retained by the filter usually have to be removed manually, or they are eliminated from the system when draining or pumping out the process water.

Presentation of the invention

It has as its object to provide a domestic appliance and a method of the type mentioned, with which a better filtering of the process water is achieved.

This object is achieved by the subject matter of the independent claims. Accordingly, therefore, a filter arrangement is provided in the drainage system. The device is designed to clean the process water by means of this filter arrangement during a cleaning phase. For this purpose, at least a portion of the process water is passed out of the tub in a forward direction through the filter assembly during a first filtering phase and then passed through the filter assembly back into the tub during a second filtering phase in a reverse direction (which is opposite to the forward direction). In this case, the filter arrangement is designed so that it has a lower filtering effect in the forward direction than in the reverse direction. As a result, in the second phase, solid residues are retained on the rear of the filter assembly (i.e., the side away from the tub in the normal flow direction), so that the process water flowing back into the tub is cleaner.

The water movement in the first and the second filter phase can be generated by the drain pump. For this purpose, the drain pump is put into operation during the first filter phase, but not during the second filter phase.

Further, the household appliance may be configured such that the water level in the drainage system during the first filter phase increases and decreases during the second filter phase. As a result, the return of the process water in the second filter phase, so to speak by itself, ie, a return pump is not mandatory.

For example, the drainage system downstream of the drainage pump may have a drainage space and a discharge line to be connected to the sewerage. The drainage chamber absorbs the water during the first filter phase and then releases it again during the second filter phase. The drainage chamber is connected via an inlet to the drainage pump and via an outlet to the drainage conduit, the inlet being located lower than the outlet. In this way, a volume is formed in which the process water running forwards through the filter arrangement in the first filter phase can be temporarily stored.

The filter arrangement may e.g. have a movable filter. It can be designed such that the filter is brought into a first configuration in the first filter phase and into a second configuration in the second filter phase, preferably switchable by the flow of the process water. For example, the filter assembly may comprise a filter tube section, through which the process water is guided, and the filter is arranged as a pivotable flap in the filter tube section.

The household appliance is advantageously operated so that in a cleaning phase (eg in the pre-wash or main rinsing) a portion of the process water is moved during the first filter phase from the tub in the forward direction through the filter assembly, while in the second filter phase, the water in the backward direction through the Filter assembly is returned to the tub. Preferably, the first and the second filter phase are cyclically repeated.

The invention is preferably realized as a dishwasher or washing machine.

Brief description of the drawings

• Fig. 1 die wichtigsten Komponenten eines Geschirrspülers,
• Fig. 2 eine Ausführung der Filteranordnung in der ersten Filterphase und
• Fig. 3 die Filteranordnung nach Fig. 2 in der zweiten Filterphase.

Further embodiments, advantages and applications of the invention will become apparent from the dependent claims and from the following description with reference to FIGS. Showing:

• Fig. 1 the most important components of a dishwasher,
• Fig. 2 an embodiment of the filter assembly in the first filter phase and
• Fig. 3 the filter arrangement after Fig. 2 in the second filter phase.

Ways to carry out the invention definitions:

The term "normal flow direction" in a piping system refers to the direction in which the process water flows to a predominant part. In the drainage system, this is the direction from the sump to the sewer.

Terms of the type "before", "behind" and "between" for components in the process water system refer to the normal flow direction of the process water. For example, the sump of the tub is located in front of the drainage pump, the discharge line is located behind the drainage pump and the drainage pump is located between the sump and the discharge line.

The term "filter effect" is to be understood as the ability to filter solids and gelatinous soils, generally non-liquid substances, from the process water. A filter with a higher Filter effect retains smaller particles than a filter with less filtering effect.

.Ausführungsbeispiel

In Fig. 1 the invention is illustrated by means of a dishwasher. This has in a known manner a tub 1 for receiving items to be washed. In the interior of the tub 1 different spraying means, such as a lower spray arm 2, an upper spray arm 3 and a ceiling nozzle 4 are provided to pressurize the dishes with process water. A circulation pump 5 serves to convey the process water via a circulation system from a sump 6 of the tub 1 up to the spraying means 2, 3 and 4. Between the circulation pump 5 and the spraying means 2, 3, 4, a switching valve 7 is provided, with which the process water can be selectively guided to individual or more of the spray.

Next, the device has a drain pump 8, which no longer required process water can be pumped out of the sump 6, and a fresh water supply comprising a valve 9 and a treatment plant 10 to supply the device fresh water.

• eine erste Ablaufleitung 13, welche zwischen dem Sumpf 6 und der Ablaufpumpe 8 angeordnet ist,
• einen hinter der Ablaufpumpe 8 angeordneten Ablaufraum 14,
• eine zweite Ablaufleitung 15, die die Ablaufpumpe 8 mit dem Ablaufraum 14 verbindet und
• eine Abführleitung 16, welche den Ablaufraum 14 mit der Kanalisation verbindet.

The drain pump 8 is part of a drain system 12. This includes further

• a first discharge line 13, which is arranged between the sump 6 and the discharge pump 8,
• a discharge chamber 14 arranged behind the discharge pump 8,
• a second drain line 15, which connects the drain pump 8 with the drain chamber 14 and
• a discharge line 16, which connects the drainage chamber 14 with the sewer system.

Further, in the drain system, a filter assembly 17 and a return valve 18 are provided, either (as in FIG Fig. 1 shown) in the first drain line 13 before the drain pump 8 or (as for the filter assembly 17 in Fig. 1 indicated by dashed lines) in the second discharge line 15 after the drain pump. 8

The various actuators of the device, in particular the pumps 5, 8, the valves 7, 9 and the treatment plant 10, 18, are controlled by a controller 11 of the device. This controller 11 is designed so that you automatically controls the device according to the process steps described below.

The filter arrangement 17 is, as already mentioned, configured to have a lower filtering effect in a forward direction 20 than in a backward direction 21. Under "forward direction", the direction of flow of the process water away from the tub 1 and "backwards" is that to the tub in to understand, cf. Arrows 20, 21 in Fig. 1 ,

Various embodiments are conceivable in order to achieve such a direction-dependent filter effect. In the embodiment shown in the figures, the filter assembly 17 has a filter 22 which is designed as a pivotable flap. Also possible is a filter body in the form of a floating body, which closes and opens by an axial movement.

A realization of this concept is in FIGS. 2 and 3 illustrated. In this embodiment, the filter assembly 17 has a filter tube section 25, through which preferably all process water, which is conveyed by the drain pump 8 passes. The filter 22 is pivotally mounted in the filter tube section 25 about a pivot axis 26. The pivot axis 26 extends offset to the center of the filter tube section 25, so that the filter 22 can be pressed by the water flow. If the filter arrangement 17 flows through in the forward direction 20 ( Fig. 2 ), the filter 22 is thus brought into a configuration in which it is arranged approximately parallel to the longitudinal direction of the pipe section 25. If the filter arrangement 17 flows through in the reverse direction 21 ( Fig. 3 ), the filter 22 from the process water flow pivoted back and stops at a stop 23, in a configuration in which it is approximately perpendicular to the longitudinal direction of the pipe section 25. Thus, the filtering effect is less in the first configuration than in the second. By a vertical arrangement, this function can be supported.

The discharge space 14 is connected via an input 28 to the drain pump 8 and via an output 29 to the discharge line 16. The input 28 is lower than the output 29, so that forms a volume between these levels that can be filled by the drain pump 8 with process water, without the process water drains into the sewer. So that the process water from the discharge space 14 can easily flow back into the tub, at least part of the discharge space 14 is arranged above the sump 6.

In an upper area, above the level of the outlet 29, the drainage space 14 is vented with a venting device 30, i. connected to the environment. The venting device 30 preferably has a float 31 which, if it reaches the process water, closes the venting device 30, but otherwise leaves the venting device 30 open (at lower process water level).

The return valve 18 is intended to prevent process water from running back into the tub 1 in certain situations, in other situations this should be possible. Therefore, the return valve 18 has two states: In a first state, it leaves in the forward direction 20 flowing process water through, in the reverse direction 21 flowing process water but not. In a second state, it flows through both in the forward direction and in the backward direction flowing process water.

For example, such a return valve 18 can be realized by a non-return valve, which can be held in the open position with an electromagnet.

The function of the household appliance will now be described below.

Basically, the household appliance goes through various cleaning phases for cleaning a wash item, for example a pre-wash cycle (optional), a main wash cycle, an intermediate wash cycle (optional, see below) and a rinse cycle. The rinse cycle is followed by a drying phase. These phases or steps are known in principle to the person skilled in the art.

Each cleaning phase is followed by a pumping phase. In this case, the process water is at least partially drained by the drain pump 8 is put into operation for a long time, so that the water level in the drain chamber 14 exceeds the height of the output 29 and process water drains into the discharge line 16. In the event that the discharge line 16, as in Fig. 1 shown, still reaches a higher level than the venting device 30, so that the water level rises up to this, the float 31 closes the venting device 30 automatically. During the Abpumphasen the filter assembly 17 is in accordance with the first configuration Fig. 2 ie it does not filter the process water.

The filter assembly 17 is used in at least one of the cleaning phases. Preferably, it is used in pre-rinsing and / or main rinsing, since in these phases, the process water is heavily contaminated with dirt particles.

To clean the process water, at least a first and a second filter phase are performed. Preferably, the household appliance is designed so that in the cleaning phase, several first and second filter phases are cycled through.

In the first filter phase, the drain pump 8 is put into operation to process water in the forward direction 20 through the filter assembly 17 to lead. In this case, the filter arrangement is in the configuration according to Fig. 2 and does not filter the water. The water level in the drainage chamber 14 increases. The air located in the discharge chamber 14 is vented via the venting device 30.

The first filter phase lasts until a desired amount of process water has passed through the filter arrangement 17. This can e.g. be achieved by a timing, assuming that the capacity of the drain pump 8 is always about the same. However, it may be provided in the discharge space 14 and an upper level sensor 33 which is disposed at the height of an upper water level to be reached 34 - reaches the water level, the drain pump 8 is turned off.

The first filter phase is followed, preferably directly, by the second filter phase. Now the drain pump 8 is turned off and the process water flows back into the tub due to gravity. The process water presses the filter 22 in the Fig. 3 shown position so that it is filtered. The filtrate collects at the side facing away from the tub 1 of the filter 22.

As a result of the return flow of the process water, the water level in the discharge space 14 drops, and at the same time air flows in via the ventilation device 30. The second filter phase continues until the process water drops to a lower water level 36 to be reached. Again, this can be timed if a predictable outflow rate is assumed. However, since contamination of the filter 22 can greatly influence the outflow rate, a lower level sensor 35 is preferably arranged in the discharge space 14, with which it can be determined when the water level has reached the lower water level 36.

At the end of the second filter phase, a part of the process water has thus been cleaned. The process water quantity filtered in the second filter phase can be substantially smaller than the total process water quantity per cleaning phase in the tub, and e.g. only 5 - 20% of the same. Repeated filter-phase cycles allow solids to be continuously filtered out of the process water without permanently removing an amount of water from the cleaning process.

The filtered solids are at the end of the second filter phase, as mentioned, on the side facing away from the tub 1 side of the filter assembly 17. During the next first filter phase they are flushed into the drain chamber 14 and the conduit 28 to then during the next second filter phase until to be swept back to the filter assembly 17. In this way, more and more filtrate accumulates behind the filter assembly 17. At the end of the cleaning phase, when the process water is at least partially discharged from the tub 1 to the sewer, the filtrate is flushed away into the sewer, so that the filter assembly 17 is cleaned again.

If so much filtrate accumulates behind the filter arrangement 17 that the filter arrangement 17 clogs in the second filter phase, this can be determined by the fact that the water level in the discharge space 14 does not reach the lower water level 36 within a predetermined period of time. Alternatively, this can also be detected by a level sensor on the tub 1, by a flow measurement on one of the drain lines 13 or 15 or by measuring the pump pressure of the circulation pump 5. In this case, the filter assembly 17 is preferably flushed with process water or fresh water in the forward direction, and although so long that a portion of the water (and thus the filtrate) flows through the discharge line 16.

The return valve 18 is in its "second state" described above, at least during the above-mentioned second filter phases, i. it does not hinder the return of the process water into the tub 1. However, if the water is e.g. falls below the lower water level 36, the return valve 18 is brought into its first state, so that it prevents further backflow and thus venting the output side of the drain pump 8. Such venting could, depending on the pump type, prevent or complicate a later start of the drain pump 8.

The present system also makes it possible to clean a screen placed in front of the circulation system. Such a screen 39 may e.g. be placed at the mouth 38 of the circulation system in the sump 5, so that the process water, which is sucked by the circulation pump 5 from the sump 6, can be filtered. Contaminations retained on this sieve can in this case be transported behind the filter arrangement 17 in the first filter phase. To promote this process, the circulating pump 5 may be shut down or throttled during at least a portion of the first filtering phase so that the contaminants are more easily released from the strainer 39, i. the circulation pump 5 is switched off at least temporarily in the first filter phase or operated with reduced delivery rate compared to the second filter phase. Operation at reduced delivery rate also prevents the circulation pump from "snorkeling" when the tank 14 is full.

Remarks:

By the present solution, the process water can be kept cleaner. As a result, the cleaning effect is improved. Thanks to the improved cleaning effect can, depending on the requirements, on a the cleaning phases, in particular on the subsequent to the main wash cycle intermediate rinse, be waived, so that, for example, in a dishwasher on the main rinse directly the rinse cycle can follow.

As mentioned, the filter assembly 17 can be arranged before or after the drain pump 8. An advantage of the arrangement after the drain pump 8 is that the filtrate, which dissolves in the forward direction when flushing the filter assembly, does not have to pass through the drain pump.

In the execution after FIGS. 2 and 3 the filter arrangement was realized in the form of a passive (ie from the process water) moving filter flap. However, the filter can also be actively moved between the filtering and the non-filtering position by a filter drive, for example.

Instead of a folding movement, the filter 22 in the pipe section 25, e.g. Also, a linear movement, which is limited by stops, perform, and so between the first and the second configuration reciprocated. In this case, in a stop position (in the first configuration), a bypass is released, so that the process water in the forward direction can flow unfiltered past the filter. Furthermore, a flexible membrane can also perform the function of switching between the two configurations and filtration, which dissolves through the flow from a sealing seat (Configuration 1) and recovers (Configuration 2).

The filter assembly may also include a fixed filter with a selectively openable bypass line. The bypass line is opened in the forward direction when the process water is flowing (so that the water does not pass through the filter) and when the process water is flowing in the backward direction (so that the water flows through the filter), eg with a non-return valve.

In the above embodiment, the drain space 14 is configured as a kind of tank. He can, however, e.g. also be formed by a sufficiently long pipe.

Instead of the vented drainage space 14, e.g. also a storage volume can be provided with a flexible wall.

While preferred embodiments of the invention are described in the present application, it is to be understood that the invention is not limited thereto and may be embodied otherwise within the scope of the following claims.

Claims (15)

Domestic appliance, in particular a dishwasher, with a tub (1) for receiving items to be washed and with a discharge system (12) comprising a discharge pump (8) through which process water to be discarded can be discharged from the tub (1), characterized in that in the discharge system ( 12) a filter arrangement (17) is arranged, and that the household appliance is configured to lead in a cleaning phase in at least a first filter phase process water from the tub (1) in a forward direction (20) through the filter assembly (17) and in a second filter phase to pass process water in a reverse direction (21) through the filter assembly (17) in the tub (1), and wherein the filter assembly (17) is designed so that it has a lower filtering effect in the forward direction (20) than in the Reverse direction (21). Domestic appliance according to claim 1, wherein in the first filter phase, the drain pump (8) is in operation, not in the second filter phase. Domestic appliance according to one of the preceding claims, wherein the household appliance is designed such that a water level in the drain system (12) increases during the first filter phase and decreases during the second filter phase. Domestic appliance according to one of the preceding claims, wherein the drainage system (12) behind the drain pump (8) has a drainage chamber (14) and a discharge line to be connected to the sewer (16), wherein the drainage space (14) via an input (28) the drain pump (8) and via an output (29) to the discharge line (16) is connected, wherein the input (28) is arranged lower than the output (29). Domestic appliance according to claim 4, wherein the drainage space (14) is vented. Domestic appliance according to one of claims 4 or 5, wherein in the discharge space (14) a level sensor (33, 35) is arranged. Domestic appliance according to claim 6, wherein the household appliance is configured to terminate the first or second filter phase, when a water level in the drain chamber (14) has reached the level sensor (33, 35). Domestic appliance according to one of the preceding claims, wherein the filter assembly (17) comprises a movable filter (22), wherein the filter (22) for the first filter phase in a first configuration and for the second filter phase in a second configuration can be brought, and in particular the filter (22) is switchable by a flow of the process water between the first and the second configuration. Domestic appliance according to claim 8, wherein the filter arrangement (17) has a filter tube section (25) through which the process water is guided, wherein the filter (22) is arranged as a pivotable flap in the filter tube section (25). Domestic appliance according to one of the preceding claims, wherein the filter arrangement (17) in front of the drain pump (8) is arranged. Domestic appliance according to one of claims 1 to 9, wherein the filter assembly (17) behind the drain pump (8) is arranged. Domestic appliance according to one of the preceding claims, wherein in the drainage system (12) a return valve (18) is arranged, which has a first and a second state, wherein the return valve (18) in the first state in the forward direction (20) passes flowing process water, not but in the backward direction (21) flowing process water, and in the second state in both the forward direction (20) and in the backward direction (21) flowing process water passes. Domestic appliance according to one of the preceding claims, wherein the household appliance is designed such that in the cleaning phase, a plurality of first and second filter phases are cycled. Domestic appliance according to one of the preceding claims, wherein it has a circulation system (5, 7) with a circulation pump (5) to convey water from a sump (6) of the tub (1) upwards, and wherein at an orifice (38) the circulation system (5, 7) in the sump (6) is arranged a sieve (39), and in particular wherein the household appliance is configured, the circulation pump (5) during at least a portion of the first filter phase with reduced compared to the second filter phase capacity to operate or shut down. Method for operating a household appliance according to one of the preceding claims, wherein in a cleaning phase ware in the tub (1) is treated with process water, and wherein during the cleaning phase, a portion of the process water during the first filter phase from the tub (1) in the forward direction (20) is moved through the filter assembly (17) and, in the second filtering phase in the backward direction (21), is moved through the filter assembly (17) into the tub (1).

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