System and method for cleaning a waste filter of a water recyling device

Abstract

A system (1) for cleaning a waste filter (100) of a water recycling device. The system comprises a pre-filter unit (20) at which water to be recycled is received. The pre- filter unit (20) comprises a water quality sensor (201) for detecting the quality of a stream of filtered water within the pre-filter unit (20), a waste filter (100) for capturing and filtering particulate matter from a stream of waste generated at the pre-filter unit (20). The system comprises a spray outlet (101) arranged to direct water at an external face (110b) of the waste filter (100) and a fluid control system (60) comprising at least one pump (50) and valve (501), the fluid control system (60) configured to control and direct filtered water from the pre-filter unit (20) to the spray outlet (101) if the water quality of the filtered water from the pre-filter unit (20) measured by the water quality sensor (201) is below a pre-determined threshold.

Description

[0001] WASTE FILTER AND WASTE FILTER CLEANING

[0002] Field of the Invention

[0003] The present disclosure relates to a system for cleaning a waste filter in a water recycling device. In particular it relates to a system comprising a spray outlet and a fluid control system for controlling fluid flow to the spray outlet based on the quality of the water.

[0004] Background of the invention

[0005] Water recycling devices may be used for recycling water from devices which generate process water, such as washing machines, dishwashers etc.

[0006] Water recycling devices are known from at least WO 2024 / 076280 Al which describes a water recycling device comprising a filtration tank. As the water from a device which generates process wash water, such as a washing machine, may comprise fibres, particles etc. such particulate matter must be filtered from the water to be recycled. The particulate matter has a negative impact on water recycling performance. However, once the particulate matter has been filtered from the water to be recycled it should also be captured to ensure that it does not end up in a sewage system. The capturing of particulate matter can result in substantial build up. Systems, devices and processes for reducing the maintenance required would be advantageous.

[0007] A particular issue in recycling washing machine water is the presence of microplastics. Microplastics may be generated when washing synthetic fabrics. The traditional definition of microplastics is plastic particles having a length of less than 5 mm. The microplastic particles generated from washing synthetic textiles are generally much smaller than 5 mm in length, they may be for example less than 1 mm, such as less than 0.5mm. These small particles should be captured and not discarded to municipal wastewater. Ideally, the capturing of the particles should be fault tolerant, such that if a water recycling device fails, the microparticles are captured. of the invention

[0008]

[0009] Accordingly, the present invention preferably seeks to mitigate, alleviate or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in any combination and solves at least the above problems described above by providing a system for cleaning a waste filter of a water recycling device. The system comprises a pre-filter unit at which water to be recycled is received. The pre-filter unit comprises a water quality sensor for detecting the quality of a stream of filtered water within the pre-filter unit, a waste filter for capturing and filtering particulate matter from a stream of waste generated at the pre-filter unit. The system comprises a spray outlet arranged to direct water at an external face of the waste filter and a fluid control system comprising at least one pump and valve, the fluid control system configured to control and direct filtered water from the pre-filter unit to the spray outlet if the water quality of the filtered water from the pre-filter unit measured by the water quality sensor is below a pre-determined threshold.

[0010] A method for cleaning a waste filter of a water recycling device is also provided. Further advantageous embodiments are disclosed in the appended and dependent patent claims.

[0011] Brief description of the drawings

[0012] These and other aspects, features and advantages of which the invention is capable will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which Figure l is a partial cross-section and schematic view of a system comprising a waste filter according to an example. The flow of water within the system is shown by the arrows on the connecting lines of the schematic.

[0013] Figure 2 is a partial cross-section and schematic view of a pre-filter tank and a waste filter according to an example.

[0014] Figure 3 is a front view of a spray outlet according to an example. Detailed description

[0015] Figure 1 shows a system 1 for cleaning a waste filter 100 in a water recycling device. The system 1 comprises a pre-filter unit 20 at which water to be recycled is received. The pre-filter unit 20 generates a stream of waste comprising particulate matter and a stream of filtered water. The pre-filter unit 20 comprises a water quality sensor 201 for detecting the quality of a stream of filtered water. The waste filter 10 of the system 1 is for capturing and filtering particulate matter from the stream of waste generated by the pre-filter unit 20. A spray outlet 101 is arranged to direct water at an external face 110b of the waste filter 100. The system comprises a fluid control system 60 comprising at least one pump 50 and at least one valve 501. The fluid control system 60 is configured to control and direct filtered water from the pre-filter unit 20 to the spray outlet 101 if the water quality of the filtered water from the pre-filter unit 20 is below a pre-determined threshold.

[0016] The pre-filter unit 20 is a device for receiving and filtering process water, in particular process wash water from a device which generates process water 2. The device which generates process water may be for example a washing machine, dishwasher etc. The pre-filter unit 20 receives the process water and as described previously, generates a stream of filtered process water and a stream of waste. The stream of waste comprising particulate matter generated by the pre-filter unit 20 falls due to gravity to the base of the pre-filter unit 20. As the stream of waste comprises relatively less water compared to the stream of filtered water generated by the pre-filter unit 20 it is comparatively heavier and gathers at the base of the pre-filter unit 20. To ensure that the stream of waste is capable of being removed from the system 1, the stream of waste is captured by the waste filter 100. The waste filter 100 is removable from the system 1 and may be emptied by a user or during a maintenance process.

[0017] The stream of waste is received at the waste filter 100 via an inlet 102. The inlet 102 is arranged above the waste filter 100 such that the stream of waste may fall due to gravity into an internal region of the waste filter 100. The internal region of the waste filter 100 is defined by a mesh filter screen 110 having a sealed and closed lower portion, and an opening 111 at its upper portion through which the stream of waste from the inlet 102 may pass. Even though the stream of waste has a reduced water content, it still comprises water to some extent. Therefore, the mesh filter screen 110 captures the particulate matter and allows the water content to pass through the mesh filter screen 110. Water which has passed through the mesh filter screen 110 exits the waste filter 100 at a disposal outlet 103. The disposal outlet 103 is generally connected to a drain, or sewage.

[0018] During collection of the stream of waste in the waste filter 100, the particulate matter gathers in the internal region of the filter 100 and may in some instances gather along an internal face 110a of the mesh filter screen 110 due to for example surface tension. As the particulate matter gathers in the internal region of the filter 100 the mesh of the mesh filter 110 may become blocked or clogged reducing the ability for the water in the waste stream to exit through the mesh. This blocking of the mesh filter 110 results in the mesh filter filling with water and needing to be emptied prior to it being filled with particulate matter, as it is partially filled with water which should have exited the mesh filter 110 and through the disposal outlet 103. This necessitates emptying of the filter prematurely, that is, before it has been filled with particulate matter as it is partially filled with water.

[0019] To overcome the tendency described above for particulate matter to gather on the mesh filter 110, the system comprises at least one spray outlet 101 arranged to direct water at the external face 110b of the filter 100. As shown in figure 1, the system may comprise a plurality of spray outlets 101 such as two spray outlets 101, each of the spray outlets 101 arranged to direct water at the external face 110b of the filter 100.

[0020] The spray outlets 101 spray a stream of water at the external face 110b, and the stream of water tends to dislodge particulate matter on the internal face 110a of the filter 100, where it thereafter gathers at the base of the filter 100.

[0021] The spray outlet 101, or outlets 101, each have a backpressure, or fluid resistance P2. This is the fluid resistance of water provided to the spray outlet 101. The spray outlet 101 ideally has a slit outlet 101 for providing a vertically elongated stream of water at the external face 101b of the mesh filter 110. As shown in figure 1, by providing a slit outlet 101 the full height of the mesh filter 110 may receive the spray. Ideally, the outlet 101 is arranged adjacent a lower portion of the mesh filter 110, such an arrangement has been shown to best promote the dislodging of particulate matter within the mesh filter 110. The slit form of the outlet is shown in figure 3. The slit of the outlet 101 is oriented in line with the vertical axis of the waste filter 100 as shown in figure 1.

[0022] Spraying, or backflushing a filter with a stream of water is known within the field of filtering devices. For example, WO 2024 / 076280 Al described a backflushing system for a filtration tank. However, using water to spray the filter 110 also increases the water consumption of the system 1. Any backflushing water used to spray the filter 100 in the present system 1 will collect at the disposal outlet 103 and cannot be recycled.

[0023] To reduce water consumption, and increase water recycling efficiency, the present system comprises a fluid control system 60 adapted to measure the quality of the water in the pre-filter tank 20. If the water of the stream of filtered water in the pre-filter 20 is below a water quality threshold such that it is non-recyclable, the water is directed to the spray outlet 101 to backflush the filter 100, and in particular the mesh screen 110, and thereafter it is disposed via the disposal outlet 103. With such a fluid control system 60, only water which is non-recyclable is used to backflush the waste filter 100 and no recyclable water is discarded unnecessarily.

[0024] If the quality of the stream of filtered water is above the pre-determined threshold then it may be stored and / or recycled. Generally, the system 1 comprises a storage tank 40 for storing filtered water above the pre-determined threshold. The fluid control system 60 can transfer, such as pump via the pump 50 the filtered water above the pre-determined threshold to the storage tank 40.

[0025] The water quality of the stream of filtered water in the pre-filter 20 is measured by a water quality sensor 201. The water quality sensor 201 is ideally, a water quality sensor as described in WO 2023 / 219553 Al. The water quality sensor 201 is ideally arranged within the pre-filter 20 and measures the colour and / or turbidity of the stream of filtered water via a white light emitting element and an infra-red light emitting element. As described in WO 2024 / 076280 Al, the water quality sensor 201 may be arranged on a backflushing line within the pre-filter tank 20.

[0026] The backflushing system 210 of the pre-filter 20 has a backflushing outlet 211 to direct water at a filter screen of the pre-filter unit 20. The backflushing outlet 211 has a backpressure, or fluid resistance Pl. This is the fluid resistance that water provided to the backflushing system experiences on expulsion from the backflushing outlet 211. The storage tank 40 forms a receptacle for storing water to be recycled. The storage tank comprises a storage outlet 401 at which water is received within the storage tank. The stream of filtered water having a quality above the pre-determined threshold is provided to the storage tank via the storage outlet 401, where it is subsequently stored for recycled. Ideally the storage tank 40 comprises a disinfection system 30. The storage outlet 401 is arranged downstream from the disinfection system 30 such that the stream of filtered water above the pre-determined threshold is provided to the disinfection system 30 prior to being provided to storage tank 40. The disinfection system 30 may be an electrolytic disinfection system 30 for generating free chloride ions within a volume of water. The disinfection system may be based on the electrolytic disinfection principle described in WO 2017 / 202828 Al. As the stream of filtered water is provided to the disinfection system 30 prior to being stored in the storage tank 40 all water entering the tank is contacted by the disinfection system 30 prior to storage. The storage outlet 401 is ideally arranged at an upper portion of the storage tank 40 such that water may be sprayed from the outlet at a pressure sufficient to dislodge any film matter present on the internal walls of the storage tank 40. As recycled water, especially water from a washing machine or dishwasher etc may comprise organic matter such as bacteria which is not filterable by the pre-filter 20, the disinfection system reduces the potential for the organic matter to grow within the storage tank 40. By placing the disinfection system 30 upstream of the storage tank 40 rather than within the storage tank 40, the disinfection system 30 does not rely on diffusion of the free chloride ions within the storage tank but rather all of the stream of filtered water is disinfected and subsequently mixed via the expulsion of water from the storage outlet 401.

[0027] The storage outlet 401 has a backpressure, or fluid resistance P3. This is the fluid resistance that water provided to the storage tank experiences on expulsion from the storage outlet 401.

[0028] The fluid control system 60 comprises a processing unit 601, at least one pump 50 and at least one valve 501 to control the flow of fluid within the system 1. The processing unit 601 is in electrical communication with the pump 50, and the at least one valve 501. Generally, as would be understood, the fluid control system comprises a plurality of valves 501a, 501b, 501c such that water can be directed throughout the system 1. The pump 50 is controlled by the processing unit 601. The opening and closing of the valves 501a, 501b, 501c is controlled by the processing unit 601 of the fluid control system 60. The fluid control system 60 is also in electrical communication with the water quality sensor 201. The quality of water determined via the water quality sensor 210 is communicated to the processing unit 601, which determines the flow of water within the system 1 by controlling the at least one pump 50 and the at least one valve 501.

[0029] As described above, each of the backflushing outlet 211 of the backflushing system 210, the spray outlet 101, and the storage outlet 401 have a specific fluid resistance. It has been identified that by designing the outlets such that the fluid resistance of the spray outlet 101 is substantially equivalent to the fluid resistance of the backflushing outlet 211, equal flow rates can be achieved when directing filtered water having a quality below the threshold simultaneously to the backflushing outlet 211 and the spray outlet 101. This is especially advantageous as then the flow rate of only one of the two fluid lines needs to be measured to know the flow rates of both fluid lines. Additionally, the fluid resistance of the storage outlet 401 is substantially equivalent to the fluid resistance of the backflushing outlet 211 of the backflushing system 210. This ensures that when filtered water having a quality above the pre-determined threshold is simultaneously being provided to the storage tank 40 and the backflushing system 210, only one flow rate needs to be measured to know the flow rate in the respective, nonmeasured line. The fluid resistance of each of the spray outlet 101, the backflushing outlet 211, and the storage outlet 401 may be substantially equal, such that Pl ~ P2 ~ P3.

[0030] The pre-filter unit 20 ideally has a safety overflow outlet 203. The safety overflow outlet 203 is an opening in an upper region of the pre-filter unit 20 through which water may flow, if the volume of water within the pre-filter unit 20 reaches the safety overflow outlet 203. The safety overflow outlet 203 is directed into the inlet 102 to the waste filter 100. This ensures that water overflowing a specific safety level, the quality of which is unknown, must enter the waste filter 100 before being discarded to a drain. In such an arrangement, it can be ensured that particles, for example microplastics, that may not have been filtered by the pre-filter unit enter the waste filter 100 prior to entering the drain. The system 1 for a water recycling device as described herein may ideally be provided in fluid connection to a washing machine and / or a dishwasher. A washing machine and / or a dishwasher may incorporate the water recycling device, and therein the system 1. The water recycling device comprising the system 1 may be provided separately, or within, the washing machine and / or dishwasher.

[0031] The terms upper and lower as used herein refer, unless otherwise indicated, to the orientation of the waste filter 100 as shown in figures 1 and 2. Waste to be captured enters the waste filter 100 from the upper portion from the outlet 102 and falls due to gravity to a lower portion. Additionally, unless indicated otherwise, the terms above and below correspond to the orientation of the waste filter 100 as shown in figures 1 and 2. When the terms above and below are used to refer to being above a pre-determined threshold, or below a pre-determined threshold, then this usage refers to the quality of water being better than, or worse than, the pre-determined threshold quality respectively.

[0032] Although, the present invention has been described above with reference to specific embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the invention is limited only by the accompanying claims.

[0033] In the claims, the term “comprises / comprising” does not exclude the presence of other elements or steps. Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor. Additionally, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and / or advantageous. In addition, singular references do not exclude a plurality. The terms “a”, “an”, “first”, “second” etc do not preclude a plurality. Reference signs in the claims are provided merely as a clarifying example and shall not be construed as limiting the scope of the claims in any way.

Claims

CLAIMS1. A system (1) for cleaning a waste filter (100) of a water recycling device, the system comprising:- a pre-filter unit (20) at which water to be recycled is received, the pre-filter unit (20) comprising a water quality sensor (201) for detecting the quality of a stream of filtered water within the pre-filter unit (20), wherein the pre-filter unit (20) generates a stream of waste comprising particulate matter, and the stream of filtered water,- a waste filter (100) for capturing and filtering particulate matter from the stream of waste generated at the pre-filter unit (20),- a spray outlet (101) arranged to direct water at an external face (110b) of the waste filter (100),- a fluid control system (60) comprising at least one pump (50) and valve (501), the fluid control system (60) configured to control and direct filtered water from the prefilter unit (20) to the spray outlet (101) if the water quality of the filtered water from the pre-filter unit (20) measured by the water quality sensor (201) is below a predetermined threshold.

2. The system (1) according to claim 1, wherein the system (1) comprises a water storage tank (40), and wherein the fluid control system (60) is configured to direct filtered water from the pre-filter unit (20) to the water storage tank (40) if the quality of the filtered water from the pre-filter unit (20) is above a pre-determined threshold.

3. The system (1) according to claim 2, wherein the pre-filter unit (20) comprises a backflushing system (210) for backflushing the pre-filter unit (20), the backflushing system comprising a backflushing outlet (211) to direct water at a filter screen of the pre-filter unit (20), and wherein the fluid control system (60) is configured to direct filtered water from the pre-filter unit (20) to the backflushing outlet (211) of the backflushing system (210) and the spray outlet (101) and / or water storage tank (40).

4. The system (1) according to claim 3, wherein the fluid resistance of the outlet (211) of the backflushing system (210) is substantially equivalent to the fluid resistance of the spray outlet (101).

5. The system (1) according to claim 3 or 4, wherein the fluid resistance of a storage outlet (401) directed into the water storage tank (40) is substantially equivalent to the fluid resistance of the backflushing outlet (211) of the backflushing system (210).

6. The system (1) according to any of claims 1 to 5, wherein the system (1) comprises a plurality of spray outlets (101), each of the spray outlets (101) arranged to direct water at the external face (110b) of the waste filter (100).

7. The system (1) according to any of claims 1 to 6, wherein the pre-filter unit (20) comprises a safety overflow outlet (203), wherein the safety overflow outlet (203) is directed into the waste filter (100).

8. A method for cleaning a waste filter (100) of a water recycling device, the method comprising:- receiving water to be recycled and filtered in a pre-filter unit (20), wherein the prefilter unit (20) generates a stream of filtered water and a stream of waste comprising particulate matter,- receiving the stream of waste from the pre-filter unit (20) in the waste filter (100), - detecting the quality of the stream of filtered water within the pre-filter unit (20) via a water quality sensor (201) provided to the pre-filter unit (20), and,- if the quality of the stream of filtered water is below a pre-determined threshold, directing the stream of filtered water to a spray outlet (101) arranged to direct the stream of filtered water at an external face (101b) of the waste filter (100) in order to dislodge particulate matter from the internal face (101a) of the waste filter (100).

9. A washing machine and / or dishwasher comprising the system (1) according to any of claims 1 to 7, wherein the water to be recycled is received from the washing machine and / or dishwasher.

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