Patent Publication Number: US-2021189699-A1

Title: Method for recycling water and a water recycling device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 16/462,860, which is a national phase of International Application No. PCT/SE2017/051159 filed on Nov. 22, 2017, which claims priority from Sweden Application No. 1651553-8, filed on Nov. 25, 2016 and Sweden Application No. 1651550-4 filed on Nov. 25, 2016, each of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The apparatuses, systems and methods described herein generally relates to water recycling. More particularly, concepts for improved hygienic conditions in water recycling applications are being presented. 
     BACKGROUND 
     In many parts of the world, clean water is becoming a scarce commodity. Consequently, systems for purification and recycling of water has found applications across many fields. Conventional water recycling devices can be effective, but is often costly, and requires frequent maintenance and major modifications to existing piping. 
     An example of a water recycling device is known from e.g. SE469413. However, there is still a need for improved water recycling devices in terms of reliability of removal of contaminants, cost, and ease of installation. 
     SUMMARY OF THE INVENTION 
     It is an object of the present inventive concept to mitigate, alleviate or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in combination. 
     According to a first aspect of the inventive concept, these and other objects are achieved in full, or at least in part, by a method for recycling water in a water recycling device, said method comprising: receiving used water via a drain; determining a water quality measure of said used water; if said water quality measure of said used water is above a first quality threshold, feeding said used water to a valve arrangement; in said valve arrangement, forming water to be treated by providing external water, said used water or a combination of said external water and said used water; generating treated water by treating said water to be treated using a water treatment arrangement; and feeding said treated water to an outlet. 
     The step of forming water to be treated by providing external water, said used water or a combination of said external water and said used water, may comprise sub-steps of providing only said external water for forming said water to be treated if said water quality measure is below said first quality threshold, or providing only said used water for forming said water to be treated if said water quality measure is above said first quality threshold. 
     The step of forming water to be treated by providing external water, said used water or a combination of said external water and said used water, may comprise sub-steps of providing only said external water for forming said water to be treated if said water quality measure is below said first quality threshold and a second quality threshold, providing said combination of said external water and said used water for forming said water to be treated if said water quality measure is above said first quality threshold but below said second quality threshold, or providing only said used water for forming said water to be treated if said water quality measure is above said first quality threshold and said second quality threshold. 
     The step of generating treated water by treating said water to be treated using a water treatment arrangement may comprise sub-steps of filtering said water to be treated, and reducing a harmful effect of microorganisms in said water to be treated by using UV light. 
     According to a second aspect of the inventive concept, these and other objects are achieved in full, or at least in part, by a water recycling device comprising: an outlet configured to output treated water; a drain for collecting used water output from said outlet; a return path in liquid communication with said drain; a treatment path in liquid communication with said return path and said outlet; a external water path in liquid communication with said treatment path, said external water path being connected to a external water outlet; a valve arrangement configured to accept as inputs said used water from said return path and/or external water from said external water path, said valve arrangement being placed between said return path and said treatment path, said valve arrangement being configured to direct said inputs to said treatment path, said valve arrangement being configured to mix said external water with said water from said return path; a circulation pump for providing a flow in said water recycling device; and a water treatment arrangement placed downstream of said valve arrangement. 
     The water recycling device may comprise a heating arrangement placed downstream of and/or combined with said water treatment arrangement. 
     The heating arrangement may be combined with a UV light treatment arrangement into a single piece of equipment. 
     The water treatment arrangement may comprise a filter arrangement. 
     The water recycling device may comprise a valve discard path configured to discharge water from said water recycling device, and said valve arrangement may be further configured to direct said water from said return path to said valve discard path. 
     The valve arrangement may comprise at least a first and a second valve arrangement, and said first valve may be configured to accept as input said used water from said return path, said first valve arrangement may be configured to direct said used water from said return path to said treatment path, and said second valve arrangement may accept as input said external water from said external water path, said second valve arrangement may be configured to direct said external water to said treatment path. 
     The first valve arrangement may be configured to direct said used water from said return path to said valve discard path. 
     The drain may comprise a drain discard path configured to discharge used water from said water recycling device. 
     The water recycling device may comprise a sensor arrangement configured to measure a water quality parameter in water in the water recycling device. 
     The sensor arrangement may comprise an electrical conductivity sensor and a UV-sensor. 
     The UV sensor may be arranged in said heating arrangement. 
     According to a third aspect of the inventive concept, these and other objects are achieved in full, or at least in part, by a water recirculating shower comprising a water recycling device according to the second aspect of the inventive concept. 
     Other objectives, features and advantages of the present inventive concept will appear from the following detailed disclosure, from the attached claims as well as from the drawings. 
     Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to “a/an/the [element, device, component, means, step, etc]” are to be interpreted openly as referring to at least one instance of said element, device, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above, as well as additional objects, features and advantages of the present inventive concept, will be better understood through the following illustrative and non-limiting detailed description of different embodiments of the present inventive concept, with reference to the appended drawings, wherein: 
         FIG. 1  schematically illustrates a conventional recirculation loop for recycling water in a shower; 
         FIG. 2  schematically illustrates an example of a water recycling device; 
         FIG. 3  schematically illustrates an example of a water recycling device; 
         FIGS. 4-6  schematically illustrates flow directions in a water recycling device. 
         FIG. 7  is a flow chart diagram of a method for recycling water in a water recycling device. 
         FIG. 8  schematically illustrates a conventional recirculation loop for recycling water in a shower. 
         FIG. 9  schematically illustrates an example of a water recycling device. 
         FIG. 10  schematically illustrates an example of a water recycling device. 
         FIGS. 11-13  schematically illustrates flow directions in a water recycling device. 
         FIG. 14  is a flow chart diagram of a method for evacuating a water recycling device. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure describes a water recycling device and methods related to the same. Initially, some terminology may be defined to provide clarification for the following disclosure. 
     In general, it has been realized by the inventors that hygienic conditions in a water recycling device can be improved by not allowing used water not adequate for recycling to contaminate external water in the water recycling device. Further, it has been realized that hygienic conditions in a water recycling device can be improved by allowing water from an external water source to pass a water treatment arrangement. 
     Throughout the present disclosure, reference is made to “external water”. External water could be for example tap water or similar. The term “external water” may herein be used for water entering the water recycling device from an external water source. The quality of external water may vary between applications. Further, the quality of external water may vary between different countries. 
     Throughout the present disclosure, reference is made to “treated water” as well as “used water”. Treated water may be water which has passed a water treatment arrangement and/or a heating arrangement. Treated water which leaves an outlet of the water recycling device may be referred to as used water. 
     Throughout the present disclosure, reference is made to different paths. Such paths may be for example pipes for transporting water. 
     Throughout the present disclosure, references are made to features being arranged “downstream” and/or “upstream” of certain features. The flow direction to which the terms “downstream” and “upstream” refer should be understood to be a flow direction from the drain to the outlet. In other words, the “stream” referred to in the terms “downstream” and “upstream” is a stream flowing from the drain to the outlet. 
     Throughout the present disclosure, reference is made to a “cleaning” of the water recycling device. In this context, cleaning may refer to a flushing of the water recycling device, and/or a flushing and a cleaning of the water recycling device with a cleaning agent. 
     It is to be understood that a water recycling device may refer to a water recirculation device. 
     With reference to  FIG. 1 , a conventional recirculation loop  100  for recycling water in a shower is shown. The recirculation loop  100  comprises a drain  104  for collecting water emitted from a nozzle  102 . The water collected by the drain  104  is directed to a valve  106  which is configured to direct the water either to a discard water pipe  108  or towards the nozzle  102 . A pump  110  provides a flow towards a valve  107 , which accepts as inputs the collected water and potable water from a potable water source  112 . The collected water can then be mixed with the potable water, and emitted through the nozzle  102 . In some cases, the potable water may be exchanged for water being non-potable. 
     With reference to  FIG. 2 , a water recycling device  200  is shown. The water recycling device  200  comprises an outlet  238  configured to output water. The outlet  238  may be a showerhead, a nozzle, or the like. The water recycling device further comprises a drain  216  for collecting the water output by the outlet, a return/evacuation path (R/E path)  220  in liquid communication with the drain  216 , wherein the R/E path  220  comprises an inlet  218  for receiving water collected by the drain  216 . Water collected by the drain  216  may hereafter be referred to as used water. The R/E path is in liquid communication with a return path  222 . The return path  222  is in liquid communication with a treatment path  230 . The treatment path is in liquid communication with the outlet  238 . External water may enter the water recycling device via an external water path  224  in liquid communication with the treatment path  230 , wherein the external water path  224  is connected to a external water source. Water in the treatment path  230  may hereafter be referred to as water to be treated. A valve arrangement  226  may be placed between the return path  222  and the treatment path  230 . The valve arrangement  226  may be configured to accept as inputs water from the return path, for example used water, and/or external water from the external water path. The valve arrangement  226  may be configured to direct the inputs to the treatment path  230 . The valve arrangement  226  may be configured to mix the external water with the water from the return path, for example the used water. The valve arrangement may comprise a valve discard path  240 . The valve discard path may be configured to discharge water from the water recycling device  200 . A circulation pump  228  may be placed downstream of the valve arrangement  226 . The circulation pump  228  may provide for at least part of a flow of water in said water recycling device  200 . A water treatment arrangement  232  may be placed downstream of the valve arrangement  226 . The water treatment arrangement  232  may comprise a filter arrangement and/or a UV light treatment arrangement. The water treatment arrangement  232  may comprise at least one filter, such as a nanofilter, a microfilter, or a nanofilter and a microfilter. The water treatment arrangement  232  may comprise at least one particle filter and at least one microbiological filter. The water treatment arrangement  232  may comprise at least one active substance for reducing harmful effects of microorganisms in water passing the water treatment arrangement  232 . Such an active substance may for example be contained within a filter media of the filter, and/or be released to the water inside the water treatment arrangement  232 . 
     Water which has been treated by the water treatment arrangement  232  may hereafter be referred to as treated water. 
     A heating arrangement  236  may be placed downstream of the water treatment arrangement  232 . By first reducing harmful effects of microorganisms in water in the water recycling device  200  and subsequently heat the water in the water recycling device  200 , the risk for microbiological growth is reduced compared to if the water, for example being a combination of used water and external water, is first heated and then treated, i.e. filtered and UV-light treated. A reason for this being the case is that the heating arrangement may for example heat the water to a temperature where microbiological growth is favorable. The heating arrangement  236  may heat water passing the heating arrangement  236 . The heating arrangement  236  may comprise a UV light treatment arrangement. The heating arrangement  236  may be combined with the water treatment arrangement  232 . The heating arrangement  236  may comprise a UV sensor configured to detect UV light emitted from the UV light treatment arrangement after the UV light has passed through water contained within the heating arrangement  236 . The heating arrangement  236  may comprise a single piece of equipment for heating and UV light treating water. The heating arrangement  236  may provide a treatment of water. For example, the UV device may assist in reducing the harmful effects of microorganisms present in the water passing the heating arrangement  236 . Thus, water which has passed the heating arrangement  236  may be referred to as treated water. 
     Still referring to  FIG. 2 , the water recycling device  200  may comprise an evacuation path  234  in liquid communication with the treatment path  230 . An inlet of the evacuation path  234  may be placed downstream of the circulation pump. An inlet of the evacuation path  234  may be placed upstream of the water treatment arrangement  232 . The evacuation path  234  may comprise an evacuation valve arrangement configured to regulate a flow of water from the treatment path into the evacuation path. The evacuation path  234  may be in liquid communication with the R/E path  220 . The R/E path  220  may be configured to direct water received from the evacuation path  234 , to the drain via the inlet of the R/E path  220 . 
     The water recycling device  200  may be configured to heat water in the heating arrangement  236  and subsequently drain the heated water via the evacuation path to the R/E path  220 . 
     The R/E path  220  may be configured to be in a first state, wherein water in the R/E path is allowed to flow in a direction away from the drain  216 . The first state of the R/E path  220  may be achieved by not allowing water to flow through the evacuation path  234 . 
     The R/E path  220  may be configured to be in a second state, wherein water in the R/E path is allowed to flow in a direction towards the drain  216 . The second state of the R/E path  220  may be achieved by having the valve arrangement  226  set to accept only external water via the external water path  224  as input, by having the circulation pump  228  in operation, and by allowing water to flow through the evacuation path  234 . Another example of achieving the second state of the R/E path  220  is by having the circulation pump  228  stopped, not accepting external water via the external water path  224  as input, and by allowing water to flow through the evacuation path  234 . 
     Below, a number of advantages with the arrangement according to the present disclosure is presented. Reference will be made to used water, external water, and treated water. However, it is to be understood that these types of water may be interchangeable, and that any combination of external, used, and treated water is possible within the scope of the present disclosure. 
     An advantage with an arrangement according to the present disclosure is that a water quality measure of the used water collected by the drain  216  may be performed in the drain  216 . Consequently, a decision may be made whether to recycle the used water, and thus direct the water via the inlet  218  to the water treatment arrangement  232 , or if the used water should be discarded via the drain discard path  242 . If the water is deemed to be inadequate for recycling, for example if a water quality measure of the used water is below a first quality threshold, the used water may be directed to the drain discard path  242 . The used water thus never enters the return path  222  leading to the valve arrangement  226  where external water is input via the external water path  224 . As a result, a risk of used water having a water quality measure below a first quality threshold contaminating the external water is reduced. 
     Another advantage with an arrangement according to the present disclosure is that external water input via the external water path  224  to the valve arrangement  226  may be treated in the water treatment arrangement  232  before being output by the outlet  238 . Thus, a risk of allowing water containing contaminants to be output by the outlet  238  is reduced. 
     Yet another advantage with an arrangement according to the present disclosure is that water in at least part of the treatment path  230 , such as water in a part of the treatment path  230  being upstream of the inlet of the evacuation path  234 , and/or water in the water treatment arrangement  232 , and/or water in the heating arrangement  236 , may drain via the evacuation path  234 , via the return path  222 , and via the R/E path  220  to the drain  216 . By doing this, water may be prevented from standing inside the water treatment arrangement  232 . In other words, the water recycling device  200  may be emptied. In one example water may be heated in the heating arrangement  236  and subsequently drained, through the water treatment arrangement  232 , via the evacuation path  234  and the R/E path  220  to the drain  216 . This process may be repeated a number of times until a desired effect has been reached. Such a desired effect may for example be a reduction of contaminants in the water treatment arrangement  232 . In this context, contaminants should be given a broad interpretation, meaning any kind of substance harmful to humans or to the functionality of the water recycling device. The process of draining water from the water recycle device may be automated and/or scheduled to be performed at specific intervals. Hereby, the water treatment arrangement  232 , evacuation path  234 , R/E path  220  and drain  216  may be flushed with heated water. Heated water may in some cases provide a more efficient flushing and/or cleaning compared to water which has not been heated. The water recycling device  200  may be arranged such that evacuation of the water recycling device  200  may be performed using gravity. For example, the water recycling device  200  may be arranged such that no water traps are formed in the different paths of the water recycling device  200 . Further, the water recycling device  200  may be configured to be installed such that the heating arrangement  236  is arranged above the water treatment arrangement  232  with respect to gravity. Similarly, the evacuation path  234  may be arranged above the R/E path  220  with respect to gravity. In one example, the circulation pump  228 , and/or another pump arranged in the water recycling device  200 , may provide for a flow of water such that the water recycling device  200  can be emptied. 
     Yet another advantage with an arrangement according to the present disclosure is that external water may enter the valve arrangement  226 , flow via the treatment path  230  to the inlet of the evacuation path  234 , and be directed to the drain  216  via the return path  222  and R/E path  220 . Hereby, the water recycling device  200  may be flushed with external water. For example, the drain  216  may be flushed by external water. The drain  216  may for example comprise a pre-filter for filtering water collected from the outlet  238 , such as used water. The pre-filter may be a mesh filter. In this case yet another advantage is that the pre-filter may be flushed by external water. The water recycling device  200  may comprise a sensor arrangement. The sensor arrangement may be arranged in the drain  216 . The sensor arrangement may be configured to measure a number of water quality parameters in water in the water recycling device and/or in water collected by the drain  216 . The sensor arrangement may be configured to determine a water quality measure of water in the water recycling device. The sensor arrangement may comprise an electrical conductivity sensor and a UV-sensor. The electrical conductivity sensor may be arranged in the drain  216 . The UV-sensor may be arranged in the heating arrangement  236 . In this case yet another advantage is that external water may pass the sensor arrangement when the water recycling device is emptied, and thus external water may be measured by the sensor arrangement in order to set a reference value for the number of water quality parameter. 
     Yet another advantage with an arrangement according to the present disclosure is that water in at least part of the treatment path  230 , the evacuation path  234 , and return path  222  may circulate in the treatment path  230 , the evacuation path  234 , and return path  222 . In other words, at least part of the treatment path  230 , the evacuation path  234 , and return path  222  may form a loop. This water may for example be used water, external water, treated water, or any combination of used, external, and treated water. Hereby, the circulation pump  228  may be flushed. 
     Yet another advantage with an arrangement according to the present disclosure is that an internal cleaning and disinfection may be achieved by adding chemicals to the drain  216  and a disinfection cycle may subsequently be triggered. The disinfection cycle may draw water, containing the chemicals, from the drain  216  into any of the water treatment arrangement  232 , circulation pump  228 , valve arrangement  226 , and heating arrangement  236 , or any of the R/E path  220 , return path  222 , evacuation path  234 , and treatment path  230 . The disinfection cycle may be triggered from an application on a smart device, such as a smart phone. 
     The drain  216  may comprise a drain discard path  242 . The drain discard path  242  may be separated from the inlet of the R/E path  220 , such that used water which is not intended to be treated by the water treatment arrangement  232 , and thus not intended to be recycled, does not have to enter the inlet of the R/E path  220  in order to reach the drain discard path  242 . Hereby, contaminated water may be prevented from contaminating any of the elements being arranged downstream of the inlet of the R/E path  220 . 
     Referring now to  FIG. 3 , a water recycling device  300  similar to the water recycling device  200  described in conjunction with  FIG. 2  is illustrated. It is to be understood that the water recycling device  300  may comprise any of the features described above in conjunction with  FIG. 2 . The water recycling device  300  may comprise a first and a second valve arrangement  326 ,  327 . The first valve arrangement  326  may be configured to accept as input the used water from the return path  322 . The first valve arrangement may be configured to direct the used water from the return path  322  to the treatment path  330 . The second valve arrangement  327  may accept as input the external water from the external water path  324 . The second valve arrangement  327  may be configured to direct the external water to the treatment path  330 . The second valve arrangement  327  may be configured to direct the used water received from the first valve arrangement  326  to the treatment path  330 . The first valve arrangement  326  may be configured to direct the used water from the return path  322  to the valve discard path  340 . 
     Referring now to  FIGS. 4-6 , flow directions in a water recycling device are illustrated. Referring first to  FIG. 4 , when outputting water from the water recycling device, used water may be collected by the drain and enter the R/E path via the inlet of the R/E path. The used water may then be directed to the return path, and the valve arrangement. Used water, and only used water, may thus be directed to the water treatment arrangement and output by the outlet of the water recycling device. This may for example be the case if a water quality measure of the used water is above a first quality threshold and a second quality threshold. At the valve arrangement, external water may enter the water recycling device. This may for example be the case if a water quality measure of the used water is above the first quality threshold, but below a second quality threshold. In other words, a combination of used water and external water is used. It is to be understood that it is possible to use only used water, only external water, or a combination of the two. External water, and only external water, may for example be used if a water quality measure of the used water below a first quality threshold. Water to be treated may then enter the treatment path via the circulation pump and be directed to the water treatment arrangement. Treated water may then enter the heating arrangement, and subsequently be output from the outlet. 
     It is also possible to direct used water to the evacuation path (not shown). In this case, used water in the treatment path is first allowed to leave the treatment path via the evacuation path, the R/E path, and the drain, and optionally via the outlet in case any used water has already passed the inlet of the evacuation path. External water may then enter the valve arrangement and subsequently enter the treatment path and be output from the outlet via the water treatment arrangement. Hereby, it is possible to discharge used water which is for any reason deemed to be inadequate for recycling, for example if a water quality measure of the used water is below a first quality threshold. 
     Yet another possibility is for used water to enter the drain, and subsequently enter the drain discard pipe. This may for example be the case if the used water is for any reason deemed to be inadequate for recycling, for example if a water quality measure of the used water is below the first quality threshold and the second quality threshold. In this case used water never enters the inlet of the R/E path. Instead, external water may enter the valve arrangement, and subsequently enter the treatment path and be output from the outlet via the water treatment arrangement. 
     Yet another possibility is to fill the water recycling device with water. For example, external water may be introduced to the water recycling device. This may be achieved by setting the valve arrangement to accept external water as input, the evacuation valve arrangement to prevent a flow of water into the evacuation path, and by the circulation pump providing a flow of water in the water recycling device. External water may be allowed to fill the water recycling device to a level such that external water is introduced into the heating arrangement. 
     Referring now to  FIG. 5 , the evacuation valve arrangement may be set to allow a flow of water into the evacuation path, such that the water recycling device may be emptied. The circulation pump may in this case be turned off. Water may thus drain from the treatment path via the heating arrangement, the water treatment arrangement, the evacuation path, and the R/E path to the drain and subsequently to the drain discard pipe. When evacuating the water recycling device, air may be drawn through the outlet in order to equalize a pressure inside the water recycling device. The air drawn through the outlet may assist in keeping the water treatment arrangement dry, thus reducing the possibility of growth of microorganisms in the water treatment arrangement. 
     Referring now to  FIG. 6 , used water and/or external water may be looped through the treatment path, the evacuation path, and the return path. This may be achieved by first providing used and/or external water to the water recycling device. Subsequently, the valve arrangement may be set to only accept water received from the return path. The evacuation valve arrangement may be set to allow a flow of water into the evacuation path. The circulation pump may provide a flow for looping water through the treatment path, the evacuation path, and the return path. 
     Referring now to  FIG. 7 , a method for recycling water in a water recycling device is illustrated in a flow chart diagram. The method comprises the step  742  of receiving used water via a drain; the step  744  of determining a water quality measure of the used water; the step  746 , if the water quality measure of the used water is above a first quality threshold, feeding the used water to a valve arrangement; the step  748  of, in said valve arrangement, forming water to be treated by providing external water, the used water or a combination of the external water and the used water; the step  750  of generating treated water by treating the water to be treated using a water treatment arrangement; and the step  752  of feeding the treated water to an outlet. 
     A method for recycling water in a water recycling device is described below. The water recycling device may comprise an outlet configured to output treated water; a drain for collecting used water output from said outlet; a return path in liquid communication with said drain; a treatment path in liquid communication with said return path and said outlet; an external water path in liquid communication with said treatment path, said external water path being connected to an external water outlet; a valve arrangement configured to accept as inputs said used water from said return path and/or external water from said external water path, said valve arrangement being placed between said return path and said treatment path, said valve arrangement being configured to direct said inputs to said treatment path, said valve arrangement being configured to mix said external water with said water from said return path; a circulation pump for providing a flow in said water recycling device; and a water treatment arrangement placed downstream of said valve arrangement. The method may comprise receiving used water via a drain; determining a water quality measure of the used water; if said water quality measure of the used water is above a first quality threshold, feeding the used water to a valve arrangement; in the valve arrangement, forming water to be treated by providing external water, the used water or a combination of the external water and the used water; generating treated water by treating the water to be treated using a water treatment arrangement; and feeding the treated water to an outlet. 
     The step of forming water to be treated by providing external water, the used water or a combination of the external water and the used water, may further comprise sub-steps of providing only the external water for forming the water to be treated if the water quality measure is below the first quality threshold and a second quality threshold; providing the combination of the external water and the used water for forming the water to be treated if the water quality measure is above the first quality threshold but below the second quality threshold; or providing only the used water for forming the water to be treated if the water quality measure is above the first quality threshold and the second quality threshold. 
     The step of generating treated water by treating the water to be treated using a water treatment arrangement may further comprise sub-steps of filtering the water to be treated; and reducing a harmful effect of microorganisms in the water to be treated by using UV light. 
     The water quality measure may for example be a measure of electrical conductivity in the used water. The water quality measure may be detected in used water in the drain of the water recycling device. 
     The inventive concept has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended patent claims. 
     LIST OF REFERENCE SIGNS 
     
         
         
           
               100  Recirculation loop 
               102  Nozzle 
               104  Drain 
               106  Valve 
               107  Valve 
               108  Discard water pipe 
               110  Pump 
               112  Potable water source 
               200  Water recycling device 
               216  Drain 
               218  Inlet 
               220  Return/Evacuation path 
               222  Return path 
               224  External water path 
               226  Valve arrangement 
               228  Circulation pump 
               230  Treatment path 
               232  Water treatment arrangement 
               234  Evacuation path 
               236  Heating arrangement 
               238  Outlet 
               240  Valve discard path 
               242  Drain discard path 
               300  Water recycling device 
               322  Return path 
               324  External water path 
               326  First valve arrangement 
               327  Second valve arrangement 
               330  Treatment path 
               340  Valve discard path 
               742  Step of receiving used water 
               744  Step of determining a water quality measure 
               746  Step of feeding used water to a valve arrangement 
               748  Step of forming water to be treated 
               750  Step of generating treated water 
               752  Step of feeding treated water to an outlet 
           
         
       
    
     The disclosure made in the following paragraphs relates to a related aspect of the inventive concept presented above. The apparatuses, systems and methods described below generally relates to water recycling. More particularly, concepts for improved hygienic conditions in water recycling applications are being presented. 
     In many parts of the world, clean water is becoming a scarce commodity. Consequently, systems for purification and recycling of water has found applications across many fields. Conventional water recycling devices can be effective, but is often costly, and requires frequent maintenance and major modifications to existing piping. 
     An example of a water recycling device is known from e.g. SE469413. However, there is still a need for improved water recycling devices in terms of reliability of removal of contaminants, cost, and ease of installation. 
     It is an object of the present inventive concept to mitigate, alleviate or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in combination. 
     According to a fourth aspect of the inventive concept, these and other objects are achieved in full, or at least in part, by a water recycling device comprising: an outlet configured to output treated water; a drain for collecting used water output from the outlet; a return/evacuation path in liquid communication with the drain, wherein the return/evacuation path comprises an inlet for receiving water collected by the drain; a return path in liquid communication with the return/evacuation path; a treatment path in liquid communication with the return path and the outlet; an external water path in liquid communication with the treatment path, the external water path being connected to an external water outlet; a valve arrangement configured to accept as inputs used water from the return path and/or external water from the external water path, the valve arrangement being placed between the return path and the treatment path, the valve arrangement being configured to direct the inputs to the treatment path, the valve arrangement being configured to mix the external water with the used water from the return path; a circulation pump for providing a flow in the water recycling device; and a water treatment arrangement placed downstream of the valve arrangement. 
     The water recycling device may comprise a heating arrangement placed downstream of the water treatment arrangement. 
     The water recycling device may comprise an evacuation path in liquid communication with the treatment path, wherein the evacuation path is placed downstream of the valve arrangement and upstream of the water treatment arrangement. 
     The evacuation path may comprise an evacuation valve arrangement configured to regulate a flow of water from the treatment path into the evacuation path. 
     The evacuation path may be in liquid communication with the return/evacuation path. 
     The water recycling device may be configured to heat water in the heating arrangement and subsequently drain the heated water via the evacuation path to the return/evacuation path. 
     The water recycling device may be configured to circulate water in at least part of the treatment path, the evacuation path, and the return path. 
     The return/evacuation path may be configured to direct water received from the evacuation path to the drain via the inlet of the return/evacuation path. 
     The drain may comprise a drain discard path configured to discharge water from the water recycling device. 
     The return/evacuation path may be configured to be in a first state, wherein water in the return/evacuation path is allowed to flow in a direction away from the drain, and a second state, wherein water in the return/evacuation path is allowed to flow in a direction towards the drain. 
     The water recycling device may comprise a sensor arrangement configured to measure a water quality parameter in water in the water recycling device. 
     The sensor arrangement may comprise an electrical conductivity sensor and a UV-sensor. 
     According to a fifth aspect of the inventive concept, these and other objects are achieved in full, or at least in part, by a water recirculating shower comprising a water recycling device according to the first aspect of the inventive concept. 
     According to a sixth aspect of the inventive concept, these and other objects are achieved in full, or at least in part, by a method for evacuating a water recycling device, the water recycling device comprising: an outlet configured to output treated water; a drain for collecting used water output from the outlet; a return/evacuation path in liquid communication with the drain, wherein the return/evacuation path comprises an inlet for receiving water collected by the drain; a return path in liquid communication with the return/evacuation path; a treatment path in liquid communication with the return path and the outlet; an external water path in liquid communication with the treatment path, the external water path being connected to an external water outlet; a valve arrangement, wherein the valve arrangement is configured to accept as inputs used water from the return path and/or external water from the external water path, the valve arrangement being placed between the return path and the treatment path, the valve arrangement being configured to direct the inputs to the treatment path, the valve arrangement being configured to mix the external water with the used water from the return path; a circulation pump for providing a flow in the water recycling device; a water treatment arrangement placed downstream of the valve arrangement; and an evacuation path in liquid communication with the treatment path, wherein the evacuation path is placed downstream of the circulation pump and upstream of the water treatment arrangement; wherein the method comprises the steps of: feeding water in the water recycling device to the drain via the evacuation path and/or the return/evacuation path. 
     The step of feeding water in the water recycling device to the drain via the evacuation path and/or the return/evacuation path may be accomplished by gravity. 
     According to a seventh aspect of the inventive concept, these and other objects are achieved in full, or at least in part, by a method for cleaning a water recycling device, the water recycling device comprising: an outlet configured to output treated water; a drain for collecting used the water output from the outlet; a return/evacuation path in liquid communication with the drain, wherein the return/evacuation path comprises an inlet for receiving water collected by the drain; a return path in liquid communication with the return/evacuation path; a treatment path in liquid communication with the return path and the outlet; an external water path in liquid communication with the treatment path, the external water path being connected to an external water outlet; a valve arrangement, wherein the valve arrangement is configured to accept as inputs used water from the return path and/or external water from the external water path, the valve arrangement being placed between the return path and the treatment path, the valve arrangement being configured to direct the inputs to the treatment path, the valve arrangement being configured to mix the external water with the used water from the return path; a circulation pump for providing a flow in the water recycling device; a water treatment arrangement placed downstream of the valve arrangement; and an evacuation path in liquid communication with the treatment path, wherein the evacuation path is placed downstream of the circulation pump and upstream of the water treatment arrangement; the method comprising the steps of: providing the water recycling device with the used water, the external water, or a combination of the used water and the external water; and evacuating the water recycling device according to the second aspect of the inventive concept. 
     The step of providing the water recycling device with the used water, the external water, or the combination of the used water and the external water may comprise a sub-step of at least partly filling the water treatment arrangement with the used water, the external water, or a combination of the used water and the external water. 
     The step of providing the water recycling device with the used water, the external water, or the combination of the used water and the external water may comprise a sub-step of circulating the used water, the external water, or the combination of the used water and the external water in the evacuation path, the return path, and at least part of the treatment path. 
     The water recycling device may comprise a heater arrangement placed downstream of the water treatment arrangement and/or combined with the water treatment arrangement, and the step of providing the water recycling device with the used water, the external water, or the combination of the used water and the external water may comprise a sub-step of heating the used water, the external water, or the combination of the used water and the external water in the heating arrangement. 
     Other objectives, features and advantages of the present inventive concept will appear from the following detailed disclosure, from the attached clauses as well as from the drawings. 
     Generally, all terms used in the clauses are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to “a/an/the [element, device, component, means, step, etc]” are to be interpreted openly as referring to at least one instance of said element, device, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. 
     The above, as well as additional objects, features and advantages of the present inventive concept, will be better understood through the following illustrative and non-limiting detailed description of different embodiments of the present inventive concept, with reference to the appended drawings, wherein: 
       FIG. 8  schematically illustrates a conventional recirculation loop for recycling water in a shower; 
       FIG. 9  schematically illustrates an example of a water recycling device; 
       FIG. 10  schematically illustrates an example of a water recycling device; 
       FIGS. 11-13  schematically illustrates flow directions in a water recycling device. 
       FIG. 14  is a flow chart diagram of a method for evacuating a water recycling device. 
     The present disclosure describes a water recycling device and methods related to the same. Initially, some terminology may be defined to provide clarification for the following disclosure. 
     In general, it has been realized by the inventors that hygienic conditions in a water recycling device can be improved by draining water from the water recycling device when it is not used for recycling water, such as between uses, or at certain time intervals. By doing this, water may be prevented from becoming stagnant. It has further been realized that external water and/or water collected in a drain of the water recycling device may be used to flush the water recycling device. 
     Throughout the present disclosure, reference is made to “external water”. External water could be for example tap water or similar. The term “external water” may herein be used for water entering the water recycling device from an external water source. The quality of external water may vary between applications. Further, the quality of external water may vary between different countries. 
     Throughout the present disclosure, reference is made to “treated water” as well as “used water”. Treated water may be water which has passed a water treatment arrangement and/or a heating arrangement. Treated water which leaves an outlet of the water recycling device may be referred to as used water. 
     Throughout the present disclosure, reference is made to different paths. Such paths may be for example pipes for transporting water. 
     Throughout the present disclosure, references are made to features being arranged “downstream” and/or “upstream” of certain features. The flow direction to which the terms “downstream” and “upstream” refer should be understood to be a flow direction from the drain to the outlet. In other words, the “stream” referred to in the terms “downstream” and “upstream” is a stream flowing from the drain to the outlet. 
     Throughout the present disclosure, reference is made to a “cleaning” of the water recycling device. In this context, cleaning may refer to a flushing of the water recycling device, and/or a flushing and a cleaning of the water recycling device with a cleaning agent. 
     Throughout the present disclosure, a “water quality parameter” may be interchangeably used with a “water quality measure”. 
     It is to be understood that a water recycling device may refer to a water recirculation device. 
     With reference to  FIG. 8 , a conventional recirculation loop  1100  for recycling water in a shower is shown. The recirculation loop  1100  comprises a drain  1104  for collecting water emitted from a nozzle  1102 . The water collected by the drain  1104  is directed to a valve  1106  which is configured to direct the water either to a discard water pipe  1108  or towards the nozzle  1102 . A pump  1110  provides a flow towards a valve  1107 , which accepts as inputs the collected water and potable water from a potable water source  1112 . The collected water can then be mixed with the potable water, and emitted through the nozzle  1102 . In some cases, the potable water may be exchanged for water being non-potable. 
     With reference to  FIG. 9 , a water recycling device  1200  is shown. The water recycling device  1200  comprises an outlet  1238  configured to output water. The outlet  1238  may be a showerhead, a nozzle, or the like. The water recycling device further comprises a drain  1216  for collecting the water output by the outlet, a return/evacuation path (R/E path)  1220  in liquid communication with the drain  1216 , wherein the R/E path  1220  comprises an inlet  1218  for receiving water collected by the drain  1216 . Water collected by the drain  1216  may hereafter be referred to as used water. The R/E path is in liquid communication with a return path1  222 . The return path  1222  is in liquid communication with a treatment path  1230 . The treatment path is in liquid communication with the outlet  1238 . External water may enter the water recycling device via an external water path  1224  in liquid communication with the treatment path  1230 , wherein the external water path  1224  is connected to an external water source. Water in the treatment path  1230  may hereafter be referred to as water to be treated. A valve arrangement  1226  may be placed between the return path  1222  and the treatment path  1230 . The valve arrangement  1226  may be configured to accept as inputs water from the return path, for example used water, and/or external water from the external water path. The valve arrangement  1226  may be configured to direct the inputs to the treatment path  1230 . The valve arrangement  1226  may be configured to mix the external water with the water from the return path, for example the used water. The valve arrangement may comprise a valve discard path  1240 . The valve discard path may be configured to discharge water from the water recycling device  1200 . A circulation pump  1228  may be placed downstream of the valve arrangement  1226 . The circulation pump  1228  may provide for at least part of a flow of water in said water recycling device  1200 . A water treatment arrangement  1232  may be placed downstream of the valve arrangement  1226 . The water treatment arrangement  1232  may comprise a filter arrangement and/or a UV light treatment arrangement. The water treatment arrangement  1232  may comprise at least one filter, such as a nanofilter, a microfilter, or a nanofilter and a microfilter. The water treatment arrangement  1232  may comprise at least one particle filter and at least one microbiological filter. The water treatment arrangement  1232  may comprise at least one active substance for reducing harmful effects of microorganisms in water passing the water treatment arrangement  1232 . Such an active substance may for example be contained within a filter media of the filter, and/or be released to the water inside the water treatment arrangement  1232 . Water which has been treated by the water treatment arrangement  1232  may hereafter be referred to as treated water. 
     A heating arrangement  1236  may be placed downstream of the water treatment arrangement  1232 . By first reducing harmful effects of microorganisms in water in the water recycling device  1200  and subsequently heat the water in the water recycling device  1200 , the risk for microbiological growth is reduced compared to if the water, for example being a combination of used water and external water, is first heated and then treated, i.e. filtered and UV-light treated. A reason for this being the case is that the heating arrangement may for example heat the water to a temperature where microbiological growth is favorable. The heating arrangement  1236  may heat water passing the heating arrangement  1236 . The heating arrangement  1236  may comprise a UV light treatment arrangement. The heating arrangement  1236  may be combined with the water treatment arrangement  1232 . The heating arrangement  1236  may comprise a UV sensor configured to detect UV light emitted from the UV light treatment arrangement after the UV light has passed through water contained within the heating arrangement  1236 . The heating arrangement  1236  may comprise a single piece of equipment for heating and UV light treating water. The heating arrangement  1236  may provide a treatment of water. For example, the UV device may assist in reducing the harmful effects of microorganisms present in the water passing the heating arrangement  1236 . Thus, water which has passed the heating arrangement  1236  may be referred to as treated water. 
     Still referring to  FIG. 9 , the water recycling device  1200  may comprise an evacuation path  1234  in liquid communication with the treatment path  1230 . An inlet of the evacuation path  1234  may be placed downstream of the circulation pump. An inlet of the evacuation path  1234  may be placed upstream of the water treatment arrangement  1232 . The evacuation path  1234  may comprise an evacuation valve arrangement configured to regulate a flow of water from the treatment path into the evacuation path. The evacuation path  1234  may be in liquid communication with the R/E path  1220 . The R/E path  1220  may be configured to direct water received from the evacuation path  1234 , to the drain via the inlet of the R/E path  1220 . 
     The water recycling device  1200  may be configured to heat water in the heating arrangement  1236  and subsequently drain the heated water via the evacuation path to the R/E path  1220 . 
     The R/E path  1220  may be configured to be in a first state, wherein water in the R/E path is allowed to flow in a direction away from the drain  1216 . The first state of the R/E path  1220  may be achieved by not allowing water to flow through the evacuation path  1234 . 
     The R/E path  1220  may be configured to be in a second state, wherein water in the R/E path is allowed to flow in a direction towards the drain  1216 . The second state of the R/E path  1220  may be achieved by having the valve arrangement  1226  set to accept only external water via the external water path  1224  as input, by having the circulation pump  1228  in operation, and by allowing water to flow through the evacuation path  1234 . Another example of achieving the second state of the R/E path  1220  is by having the circulation pump  1228  stopped, not accepting external water via the external water path  1224  as input, and by allowing water to flow through the evacuation path  1234 . 
     Below, a number of advantages with the arrangement according to the present disclosure is presented. Reference will be made to used water, external water, and treated water. However, it is to be understood that these types of water may be interchangeable, and that any combination of external, used, and treated water is possible within the scope of the present disclosure. 
     An advantage with an arrangement according to the present disclosure is that a water quality measure of the used water collected by the drain  1216  may be performed in the drain  1216 . Consequently, a decision may be made whether to recycle the used water, and thus direct the water via the inlet  1218  to the water treatment arrangement  1232 , or if the used water should be discarded via the drain discard path  1242 . If the water is deemed to be inadequate for recycling, for example if a water quality measure of the used water is below a first quality threshold, the used water may be directed to the drain discard path  1242 . The used water thus never enters the return path  1222  leading to the valve arrangement  1226  where external water is input via the external water path  1224 . As a result, a risk of used water having a water quality measure below a first quality threshold contaminating the external water is reduced. The water quality measure may for example be a measure of electrical conductivity in the used water. The water quality measure may be detected in used water in the drain of the water recycling device. 
     Another advantage with an arrangement according to the present disclosure is that external water input via the external water path  1224  to the valve arrangement  1226  may be treated in the water treatment arrangement  1232  before being output by the outlet  1238 . Thus, a risk of allowing water containing contaminants to be output by the outlet  1238  is reduced. 
     Yet another advantage with an arrangement according to the present disclosure is that water in at least part of the treatment path  1230 , such as water in a part of the treatment path  1230  being upstream of the inlet of the evacuation path  1234 , and/or water in the water treatment arrangement  1232 , and/or water in the heating arrangement  1236 , may drain via the evacuation path  1234 , via the return path  1222 , and via the R/E path  1220  to the drain  1216 . By doing this, water may be prevented from standing inside the water treatment arrangement  1232 . In other words, the water recycling device  1200  may be emptied. In one example water may be heated in the heating arrangement  1236  and subsequently drained, through the water treatment arrangement  1232 , via the evacuation path  1234  and the R/E path  1220  to the drain  1216 . This process may be repeated a number of times until a desired effect has been reached. Such a desired effect may for example be a reduction of contaminants in the water treatment arrangement  1232 . In this context, contaminants should be given a broad interpretation, meaning any kind of substance harmful to humans or to the functionality of the water recycling device. The process of draining water from the water recycle device may be automated and/or scheduled to be performed at specific intervals. Hereby, the water treatment arrangement  1232 , evacuation path  1234 , R/E path  1220  and drain  1216  may be flushed with heated water. Heated water may in some cases provide a more efficient flushing and/or cleaning compared to water which has not been heated. The water recycling device  1200  may be arranged such that evacuation of the water recycling device  1200  may be performed using gravity. For example, the water recycling device  1200  may be arranged such that no water traps are formed in the different paths of the water recycling device  1200 . Further, the water recycling device  1200  may be configured to be installed such that the heating arrangement  1236  is arranged above the water treatment arrangement  1232  with respect to gravity. Similarly, the evacuation path  1234  may be arranged above the R/E path  1220  with respect to gravity. In one example, the circulation pump  1228 , and/or another pump arranged in the water recycling device  1200 , may provide for a flow of water such that the water recycling device  1200  can be emptied. 
     Yet another advantage with an arrangement according to the present disclosure is that external water may enter the valve arrangement  1226 , flow via the treatment path  1230  to the inlet of the evacuation path  1234 , and be directed to the drain  1216  via the return path  1222  and R/E path  1220 . Hereby, the water recycling device  1200  may be flushed with external water. For example, the drain  1216  may be flushed by external water. The drain  1216  may for example comprise a pre-filter for filtering water collected from the outlet  1238 , such as used water. The pre-filter may be a mesh filter. In this case yet another advantage is that the pre-filter may be flushed by external water. The water recycling device  1200  may comprise a sensor arrangement. The sensor arrangement may be arranged in the drain  1216 . The sensor arrangement may be configured to measure a number of water quality parameters in water in the water recycling device and/or in water collected by the drain  1216 . The sensor arrangement may be configured to determine a water quality measure of water in the water recycling device. The sensor arrangement may comprise an electrical conductivity sensor and a UV-sensor. The electrical conductivity sensor may be arranged in the drain  1216 . The UV-sensor may be arranged in the heating arrangement  1236 . In this case yet another advantage is that external water may pass the sensor arrangement when the water recycling device is emptied, and thus external water may be measured by the sensor arrangement in order to set a reference value for the number of water quality parameter. 
     Yet another advantage with an arrangement according to the present disclosure is that water in at least part of the treatment path  1230 , the evacuation path  1234 , and return path  1222  may circulate in the treatment path  1230 , the evacuation path  1234 , and return path  1222 . In other words, at least part of the treatment path  1230 , the evacuation path  1234 , and return path  1222  may form a loop. This water may for example be used water, external water, treated water, or any combination of used, external, and treated water. Hereby, the circulation pump  1228  may be flushed. 
     Yet another advantage with an arrangement according to the present disclosure is that an internal cleaning and disinfection may be achieved by adding chemicals to the drain  1216  and a disinfection cycle may subsequently be triggered. The disinfection cycle may draw water, containing the chemicals, from the drain  1216  into any of the water treatment arrangement  1232 , circulation pump  1228 , valve arrangement  1226 , and heating arrangement  1236 , or any of the R/E path  1220 , return path  1222 , evacuation path  1234 , and treatment path  1230 . The disinfection cycle may be triggered from an application on a smart device, such as a smart phone. 
     The drain  1216  may comprise a drain discard path  1242 . The drain discard path  1242  may be separated from the inlet of the R/E path  1220 , such that used water which is not intended to be treated by the water treatment arrangement  1232 , and thus not intended to be recycled, does not have to enter the inlet of the R/E path  1220  in order to reach the drain discard path  1242 . Hereby, contaminated water may be prevented from contaminating any of the elements being arranged downstream of the inlet of the R/E path  1220 . 
     Referring now to  FIG. 10 , a water recycling device  1300  similar to the water recycling device  1200  described in conjunction with  FIG. 9  is illustrated. It is to be understood that the water recycling device  1300  may comprise any of the features described above in conjunction with  FIG. 9 . The water recycling device  1300  may comprise a first and a second valve arrangement  1326 ,  1327 . The first valve arrangement  1326  may be configured to accept as input the used water from the return path  1322 . The first valve arrangement may be configured to direct the used water from the return path  1322  to the treatment path  1330 . The second valve arrangement  1327  may accept as input the external water from the external water path  324 . The second valve arrangement  1327  may be configured to direct the external water to the treatment path  1330 . The second valve arrangement  1327  may be configured to direct the used water received from the first valve arrangement  1326  to the treatment path  1330 . The first valve arrangement  1326  may be configured to direct the used water from the return path  1322  to the valve discard path  1340 . 
     Referring now to  FIGS. 11-13 , flow directions in a water recycling device are illustrated. Referring first to  FIG. 11 , when outputting water from the water recycling device, used water may be collected by the drain and enter the R/E path via the inlet of the R/E path. The used water may then be directed to the return path, and the valve arrangement. Used water, and only used water, may thus be directed to the water treatment arrangement and output by the outlet of the water recycling device. This may for example be the case if a water quality measure of the used water is above a first quality threshold and a second quality threshold. At the valve arrangement, external water may enter the water recycling device. This may for example be the case if a water quality measure of the used water is above the first quality threshold, but below a second quality threshold. In other words, a combination of used water and external water is used. It is to be understood that it is possible to use only used water, only external water, or a combination of the two. External water, and only external water, may for example be used if a water quality measure of the used water below a first quality threshold. Water to be treated may then enter the treatment path via the circulation pump and be directed to the water treatment arrangement. Treated water may then enter the heating arrangement, and subsequently be output from the outlet. 
     It is also possible to direct used water to the evacuation path (not shown). In this case, used water in the treatment path is first allowed to leave the treatment path via the evacuation path, the R/E path, and the drain, and optionally via the outlet in case any used water has already passed the inlet of the evacuation path. External water may then enter the valve arrangement and subsequently enter the treatment path and be output from the outlet via the water treatment arrangement. Hereby, it is possible to discharge used water which is for any reason deemed to be inadequate for recycling, for example if a water quality measure of the used water is below a first quality threshold. 
     Yet another possibility is for used water to enter the drain, and subsequently enter the drain discard pipe. This may for example be the case if the used water is for any reason deemed to be inadequate for recycling, for example if a water quality measure of the used water is below the first quality threshold and the second quality threshold. In this case used water never enters the inlet of the R/E path. Instead, external water may enter the valve arrangement, and subsequently enter the treatment path and be output from the outlet via the water treatment arrangement. 
     Yet another possibility is to fill the water recycling device with water. For example, external water may be introduced to the water recycling device. This may be achieved by setting the valve arrangement to accept external water as input, the evacuation valve arrangement to prevent a flow of water into the evacuation path, and by the circulation pump providing a flow of water in the water recycling device. External water may be allowed to fill the water recycling device to a level such that external water is introduced into the heating arrangement. 
     Referring now to  FIG. 12 , the evacuation valve arrangement may be set to allow a flow of water into the evacuation path, such that the water recycling device may be emptied. The circulation pump may in this case be turned off. Water may thus drain from the treatment path via the heating arrangement, the water treatment arrangement, the evacuation path, and the R/E path to the drain and subsequently to the drain discard pipe. When evacuating the water recycling device, air may be drawn through the outlet in order to equalize a pressure inside the water recycling device. The air drawn through the outlet may assist in keeping the water treatment arrangement dry, thus reducing the possibility of growth of microorganisms in the water treatment arrangement. 
     Referring now to  FIG. 13 , used water and/or external water may be looped through the treatment path, the evacuation path, and the return path. This may be achieved by first providing used and/or external water to the water recycling device. Subsequently, the valve arrangement may be set to only accept water received from the return path. The evacuation valve arrangement may be set to allow a flow of water into the evacuation path. The circulation pump may provide a flow for looping water through the treatment path, the evacuation path, and the return path. 
     Referring now to  FIG. 14 , a method for evacuating a water recycling device is illustrated in a flow chart diagram. The method comprises the step  1742  of feeding water in the water recycling device to the drain via the evacuation path and/or the return/evacuation path. 
     A method for evacuating a water recycling device is described below. The water recycling device may comprise an outlet configured to output treated water; a drain for collecting used water output from the outlet; a return/evacuation path in liquid communication with the drain, wherein the return/evacuation path comprises an inlet for receiving water collected by the drain; a return path in liquid communication with the return/evacuation path; a treatment path in liquid communication with the return path and the outlet; an external water path in liquid communication with the treatment path, the external water path being connected to an external water outlet; a valve arrangement, wherein the valve arrangement is configured to accept as inputs used water from the return path and/or external water from the external water path, the valve arrangement being placed between the return path and the treatment path, the valve arrangement being configured to direct the inputs to the treatment path, the valve arrangement being configured to mix the external water with the used water from the return path; a circulation pump for providing a flow in the water recycling device; a water treatment arrangement placed downstream of the valve arrangement; and an evacuation path in liquid communication with the treatment path, wherein the evacuation path is placed downstream of the circulation pump and upstream of the water treatment arrangement. The method may comprise the steps of feeding water in the water recycling device to the drain via the evacuation path and/or the return/evacuation path. The step of feeding water in the water recycling device to the drain via the evacuation path and/or the return/evacuation path may be accomplished by gravity. 
     A method for cleaning a water recycling device is described below. The water recycle device may comprise an outlet configured to output treated water; a drain for collecting used the water output from the outlet; a return/evacuation path in liquid communication with the drain, wherein the return/evacuation path comprises an inlet for receiving water collected by the drain; a return path in liquid communication with the return/evacuation path; a treatment path in liquid communication with the return path and the outlet; an external water path in liquid communication with the treatment path, the external water path being connected to an external water outlet; a valve arrangement, wherein the valve arrangement is configured to accept as inputs used water from the return path and/or external water from the external water path, the valve arrangement being placed between the return path and the treatment path, the valve arrangement being configured to direct the inputs to the treatment path, the valve arrangement being configured to mix the external water with the used water from the return path; a circulation pump for providing a flow in the water recycling device; a water treatment arrangement placed downstream of the valve arrangement; and an evacuation path in liquid communication with the treatment path, wherein the evacuation path is placed downstream of the circulation pump and upstream of the water treatment arrangement. The method may comprise the steps of providing the water recycling device with the used water, the external water, or a combination of the used water and the external water; and evacuating the water recycling device according to the method for evacuating a water recycling device as described above. 
     The step of providing the water recycling device with the used water, the external water, or a combination of the used water and the external water may comprise a sub-step of at least partly filling the water treatment arrangement with the used water, the external water, or the combination of the used water and the external water. 
     The step of providing the water recycling device with the used water, the external water, or the combination of the used water and the external water may comprise a sub-step of circulating the used water, the external water, or the combination of the used water and the external water in the evacuation path, the return path, and at least part of the treatment path. 
     The water recycling device may further comprise a heater arrangement placed downstream of the water treatment arrangement and/or combined with the water treatment arrangement, and the step of providing the water recycling device with the used water, the external water, or the combination of the used water and the external water may comprise a sub-step of heating the used water, the external water, or the combination of the used water and the external water in the heating arrangement. 
     The inventive concept has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended patent claims. 
     LIST OF REFERENCE SIGNS 
     
         
         
           
               1100  Recirculation loop 
               1102  Nozzle 
               1104  Drain 
               1106  Valve 
               1107  Valve 
               1108  Discard water pipe 
               1110  Pump 
               1112  Potable water source 
               1200  Water recycling device 
               1216  Drain 
               1218  Inlet 
               1220  Return/Evacuation path 
               1222  Return path 
               1224  External water path 
               1226  Valve arrangement 
               1228  Circulation pump 
               1230  Treatment path 
               1232  Water treatment arrangement 
               1234  Evacuation path 
               1236  Heating arrangement 
               1238  Outlet 
               1240  Valve discard path 
               1242  Drain discard path 
               1300  Water recycling device 
               1322  Return path 
               1324  External water path 
               1326  First valve arrangement 
               1327  Second valve arrangement 
               1330  Treatment path 
               1340  Valve discard path 
               1742  Step of feeding water to drain via evacuation path and/or return/evacuation path