WO2020159421A1

WO2020159421A1 - Water recirculation device with water level estimation, water flow estimation, and/or air bubble prevention

Info

Publication number: WO2020159421A1
Application number: PCT/SE2020/050062
Authority: WO
Inventors: Mårten ÖBRINK; Mikael Nilsson; Arman Mudde; Jake Snowdon; Markus FRIBERG; Alfred NYBERG
Original assignee: Orbital Systems Ab
Priority date: 2019-01-28
Filing date: 2020-01-27
Publication date: 2020-08-06
Also published as: EP3918141A1; EP3918141A4

Abstract

The present invention describes a system 1 allowing for purification and recycling of water or separation of water, wherein said system allowing for purification and recycling of water or separation of water comprises a recirculation loop, a water tank 200, a fresh water inlet 300 connected to the water tank 200, a water treatment unit, a sensor system and a control system, wherein the sensor system gives input to the control system with respect to a selection decision of either recycling of water in the system or separation of water from the system in at least one separation point, wherein there is arranged an air gap between the fresh water inlet 300 and the maximum water level in the water tank 200, wherein the water tank 200 comprises multiple level sensors which are connected to a data processing unit for the system 1, and wherein the data processing unit is arranged to register different levels in the water tank 200 and/or to calculate inflow to the water tank 200 based on water level estimation in said multiple level sensors.

Description

WATER RECIRCULATION DEVICE WITH WATER LEVEL ESTIMATION.

WATER FLOW ESTIMATION. AND/OR AIR BUBBLE PREVENTION

Field of the invention

The present invention relates to a system allowing for purification and recycling of water or separation of water.

Technical Background

Water recirculation devices are known. One example is described in WO2013/095278 which refers to a hybrid device for a recirculation shower, allowing purification and either recycling of water or discarding of water, where said hybrid device comprises a recirculation loop, a filter system with a pre-filter and a nano-filter, at least one filter quality sensor and at least one water quality sensor, and where the hybrid device is arranged to redirect the water from recirculation to drainage when the at least one filter quality sensor and/or water quality sensor indicates the need thereof.

One aim of the present invention is to provide a water recirculation device, such as a recirculation shower, with improved water level and/or flow estimation, hygienisation control and prevention of air bubble formation.

Summary of the invention

The latter stated purpose above is achieved by a system allowing for purification and recycling of water or separation of water, wherein said system allowing for purification and recycling of water or separation of water comprises a recirculation loop, a water tank, a fresh water inlet connected to the water tank, a water treatment unit, a sensor system and a control system, wherein the sensor system gives input to the control system with respect to a selection decision of either recycling of water in the system or separation of water from the system in at least one separation point, wherein there is arranged an air gap between the fresh water inlet and the maximum water level in the water tank, wherein the water tank comprises multiple level sensors which are connected to a data processing unit for the system, and wherein the data processing unit is arranged to register different levels in the water tank and/or to calculate inflow to the water tank based on water level estimation in said multiple level sensors. As notable from above, the present invention is directed to a solution where the multiple level sensors are either used to register the level in at least two different level points only, or to calculate the inflow of fresh water to the water tank, or to register the level in at least two different levels and also to calculate the inflow of fresh water. Perspectives of these alternatives are discussed below.

According to one specific embodiment, the present invention provides an improved solution for both measuring the water level inside of the water tank as well as the water inflow to the water tank. Therefore, according to one embodiment the water tank comprises multiple level sensors which are connected to a data processing unit for the system, and wherein the data processing unit is arranged to register different levels in the water tank and to calculate inflow to the water tank based on water level estimation in said multiple level sensors. As the volume of the water tank, which is a function of the cross sectional area and height, is known and may be programmed in the data processing unit, then the inflow to the water tank may be calculated based on the indication of the level sensors as a function of time. Therefore, the indication of a certain height from one sensor to another sensor based on the time passed for this change may be used to calculate the inflow. As such, the levels sensors not only detect the actual water level but also the inflow indirectly. This requires multiple level sensors. Moreover, for the entire system another sensor in the sensor system measures the outflow of water from the water recirculation system. As such, the sensor system may be able to detect and process the entire balance of water flowing into the water tank and out from the water recirculation system. Furthermore, this also implies that the data processing unit, which may be a control unit, may control and regulate the entire inflow of fresh water. The present invention according to this embodiment thus provides a simple way of both measuring water level and fresh water inflow to a water tank in a water recirculation system, e.g. in a recirculating shower. The present invention provides a solution where an in line inflow sensor is redundant, which of course is an advantage. Moreover, in relation to the expression“maximum water level”, this should be interpreted as the top level of water in the water tank plus the possible height of waves or the like which may be created in the water tank. Brief description of the drawings

In fig. 1 there is shown one specific embodiment of the present invention.

In fig. 2 there is shown another embodiment of the present invention.

In fig. 3 there is shown a measurement rod according to the present invention.

Specific embodiments of the invention

Below specific embodiments are disclosed.

As hinted above, one aspect of the present invention is to provide a controlled hygienisation. This is inter alia achieved by the incorporation of the air gap. According to one specific embodiment, the air gap is at least 20 mm, such as at least 40 mm, which in some cases may be preferable. According to yet another embodiment of the present invention, the air gap is at least 60 mm. Air gaps above 40 mm or even above 60 mm may be preferable in cases when the fresh water inlet diameter is large, relatively speaking, or when the air gap is provided close to water tank walls, of course also relatively speaking.

According to one specific embodiment of the present invention, the water tank comprises at least four level sensors, preferably more than four level sensors. To incorporate this number of sensors provides for a higher accuracy in the water level estimation and/or fresh water inflow calculation. Moreover, it may also be the foundation to ensure a more secure system where there are several level sensors in between an emergency minimum level sensor and an emergency maximum level sensor, as mentioned below. Furthermore, in the case of e.g. a recirculating shower it is suitable to regulate the inflow based on a difference between the outflow from a shower head, i.e. subsequent to a flow measurement of the outflow in a flow meter, and the level in the water tank and the fresh water inflow to the water tank, as measured in the water level tank. Therefore, to ensure a high precision of the level and inflow measurement and also a high level of measure per time unit, which is enabled by multiple level sensors, is a great advantage for the regulation of a water recirculation system.

Another aspect of the present invention is to provide an arrangement which prevents air bubble formation, especially in places where such air bubbles cause problems in the recirculation system. Air bubbles in the water recirculation system has several problems. One first is that air bubbles causes measurements problems in sensors for measurements in the water flow, such as in water quality sensors or the like. This is further discussed below. Another problem is that air bubbles may affect the water pump provided in the water recirculation system negatively.

The present invention provides several directions in relation to minimizing air bubble formation in the outflow from the water tank. One possible such direction of the invention is to control the level of water in the water tank. Therefore, according to one general core aspect of the present invention, the system involves water level detection/estimation. In

combination with providing an air gap according to the present invention, this ensures a basis to control the water level in the tank so that there is a minimized risk of too low water level and thus air bubble formation close to the water tank outlet.

Level detection/estimation according to the present invention may be performed in different ways. According to one embodiment of the present invention, the water level detection/estimation is performed by the

incorporation of multiple sensors. According to one embodiment, the water tank comprises a minimum level sensor. Already this may reduce the air bubble formation close to the water tank outflow. Furthermore, according to yet another specific embodiment of the present invention, the water tank comprises a minimum level sensor and a maximum level sensor. This is also further shown in the alternative shown in fig. 1. Moreover, here it is shown that also emergency level sensors, both for minimum and maximum water level, may be provided in the water tank. The level sensors may be of different types, e.g. EC (electric conductivity) sensors. Also this is of relevance to ensure an enough minimum water level to prevent air bubbles to be sucked into the recirculation loop and thus the water pump. Moreover, the types of level sensors according to the present invention may vary. According to one specific embodiment of the present invention, the multiple level sensors are conductivity sensors. It should be noted that also other alternatives are possible, such as radar sensors, optical sensors, ultrasonic sensors, IR sensors, etc. Another possible type of sensor is a pressure sensor working on the principle of“water column”. Such a pressure sensor or several such may be arranged in the bottom of the water tank.

It should be noted that the sensors arranged inside of the water tank are directed to detecting water level, however also other parameters are possible. For instance, conductivity sensors measure the conductivity which as such may function both for estimation of level but also as a measurement of the water quality. In this case, this measure would reflect on the water quality of the fresh water inflow, and may as such act as a reference value.

Furthermore, the sensors may be incorporated into the water tank in different ways according to the present invention. One possibility is as fixated sensors directly to a wall of the water tank. According to another specific embodiment of the present invention, the multiple level sensors are arranged on a measurement rod which is possible to fixate in the water tank at a given level. According to yet another specific embodiment of the present invention, the measurement rod comprises an end fixation extension which is arranged to fit and fixate into a water tank outflow of the water tank. Such an end fixation extension may have the design as a small plug in extension which is pushed into the water tank outflow of the water tank. Moreover, the end fixation extension may have at least double purposes. One is of course to fixate the rod and as such level sensors in the right place and at the right height. Another one is to counteract vortex formation, thus acting as a vortex breaker. The form of the tank and the water outlet position being off-center also helps to reduce vortex formation. Therefore, according to one

embodiment of the present invention, the water tank outlet is positioned off- center. In this context it may be mentioned that vortex formation is a problem with reference to the transportation of air into the recirculation loop. As mentioned above, the present invention provides several directions to reduce the air bubble formation. One first general principle according to the present invention is by using a water tank of enough size, which in itself enables a calm water inflow from the water tank into the recirculation loop of the water recirculation system. According to another embodiment of the present invention, the fresh water inlet is arranged to flow water into a mesh. One example thereof is shown in fig. 1. The mesh dampens the incoming water momentum. The mesh ensures a smooth water inflow into the water tank. Moreover, the mesh also prevents certain particles to enter into the water tank.

According to one specific embodiment of the present invention, the mesh is monofilament yarn based. Such monofilament yarns may e.g. be produced from nylon or polyester. Moreover, according to one specific embodiment, the mesh is produced from monofilament yarn and provided in double layers.

Also the mesh size of the perforated layer may of course be of relevance. According to one embodiment of the present invention, the mesh openings of the mesh are in the range of from 100 to 700 micron, such as in the range of from 100 to 400 micron, e.g. 100 or 200 micron.

According to yet another specific embodiment of the present invention, an outflow of the mesh is positioned beneath the minimum water level in the water tank implying that the outflow of the mesh is positioned beneath the water surface. This has the benefit that the outflow from the mesh is not directly led to the outflow of the water tank. This further prevents air bubbles to be led into recirculation loop and thus water pump. According to yet another specific embodiment of the present invention, an outflow of the mesh is positioned at a cross sectional distance from a water tank outflow. This ensures that there is a distance for the water flow coming out from the mesh before it flows out from the water tank. This also minimizes air bubbles to be formed, and especially not at or close to the outflow from the water tank. According to one specific embodiment of the present invention, an outflow of the mesh has a distance to a bottom of the water tank of at least 60 mm, such as at least 80 mm or even more than 100 mm which may be preferable in some cases.

Based on the above different possible components it should be stated that a system according to the present invention may comprise a water tank, a measurement rod and a mesh which are all connectable to each other into one unit. The way of connecting these may vary. According to one example, then the mesh may be connectable to an upper lid unit of the water tank. The measurement rod is also possible to fixate into this upper lid unit, and thus not only into the water tank outflow of the water tank. Furthermore, the

measurement rod may also be incorporated into the water tank as a permanent single part.

The water tank with the air gap according to the present invention is part of a water recirculation system. This system also comprises several other components, such as the recirculation loop, a water treatment unit, a sensor system and a control system. Below there is provided different alternatives of some of these and other components.

According to one specific embodiment, the water treatment unit is a light unit. This light unit may be a UV unit, e.g. a UV lamp. Moreover, according to one embodiment, the treatment unit is enclosed in a combined water heater and water treatment unit.

Furthermore, according to yet another embodiment, the water recirculation system comprises a filter system, where the filter system comprises a rough filter unit positioned in a drain of the system and a subsequent mid/fine filter unit.

Moreover, as hinted above, the water recirculation system comprises a sensor system. The sensor system may comprise the water tank level sensors discussed above, but may also comprise other sensors. According to one specific embodiment of the present invention, the water recirculation system comprises a sensor system comprising one sensor type directed to indicating the function of a water treating source in a water treatment unit, and wherein the sensor system also comprises another sensor type directed to indicating the water quality, and wherein both sensor types give input to the control system of the system with respect to a selection decision of either recycling of water in the system or separation of water from the system.

Furthermore, according to one embodiment, the water treating source in the treatment unit is a light unit and the water treating function sensor type is a light sensor, e.g. a UV sensor. Moreover, in another case the water treating function sensor type is a turbidity sensor, IR sensor or FTIR sensor.

Furthermore, as hinted above, the water quality sensor may be one or more conductivity sensors, such as EC sensors.

In most of the cases the water recirculation system comprises a drain. For example, in a recirculating shower according to the present invention, this drain may in fact be the unit in which the selection decision is made with reference to if water shall be recirculated in the shower or sent off to a sewer. According to one embodiment, the water recirculation system comprises a drain comprising at least one sensor. Therefore, according to one specific embodiment, the water quality sensor type is positioned in a drain of the system. Furthermore, the sensor system may also comprise a third sensor type being a level sensor in a drain of the system. Also the third sensor type may give input to the control system with respect to a selection decision of either recycling of water in the system or separation of water from the system.

Moreover, according to yet another specific embodiment of the present invention, the system comprises at least two separation points, wherein one first separation point is positioned within the system to allow for recirculation of clean water or separation of a first separated stream of water not intended to be recirculated in the system, and wherein one second separation point is arranged for separation of the first separated stream of water in at least one high quality water stream and in one low quality water stream, and wherein a decision of recirculation or separation is made by the control unit based on the measurement of water quality. Furthermore, according to another embodiment, the system comprises a separation point within the system to allow for recirculation of clean water or separation of at least two separated streams of water not intended to be recirculated in system, wherein the at least two separated streams of water differ in water quality, and wherein a decision of recirculation or separation is made by the control unit based on the measurement of water quality. Moreover, the system may be arranged to recirculate clean water to another system or in the water recirculation device itself. Furthermore, the system may be arranged so that separated water is collected in another unit or system.

According to yet another specific embodiment, the water tank comprises at least four level sensors, preferably more than four level sensors, more preferably at least six level sensors, optionally arranged along a measurement rod, and wherein the level sensors are connected to a micro controller with an analogue to digital converter (ADC). Preferably, two electrodes are arranged at a level 0, and wherein other electrodes are arranged individually at higher levels. This set-up implies that when using electrode pairs to measure, these are arranged in a vertical direction at all levels except at level 0, where it is preferred to arrange one electrode pair (two electrodes). This set-up enables to measure several discrete levels by only incorporating single electrodes. This a is a great advantage over traditional electrode measurement systems. When using conductivity sensor electrodes and a set-up suggested above it is a prerequisite to connect the electrodes to a micro controller for data and software processing. Suitably, all electrodes are connected to a control unit for controlling the entire system. Moreover, when implementing multiple electrodes in a set-up as suggested above, then also a discharge sequence should be used for discharging the electrodes.

According to yet another specific embodiment of the present invention there is provided a measurement rod comprising at least four integrated level sensors, preferably more than four level sensors, more preferably at least six level sensors, which level sensors are positioned along the measurement rod and are connected to a micro controller with an analogue to digital converter (ADC). In line with the above, according to one embodiment two electrodes are arranged at a level 0, and other electrodes are arranged individually at higher levels.

The present invention is also directed to a method for measuring level in a system and/or with a measurement rod according to according to the present invention, wherein all measurements are performed using single electrodes above level 0 and wherein the method involves sending time passed and level to a control unit. According to one embodiment, the method involves using conductivity sensor electrodes and measuring the conductivity between single electrodes above level 0.

Furthermore, the present invention also refers to a method involving using multiple conductivity sensors in a system according to the present invention, for measuring water level, fresh water inflow to and water quality of water in a water tank. According to this specific embodiment, the multiple level sensors in the water tank also act as an input for water quality.

Moreover, and as mentioned above, the system suitably also comprises a flow meter measuring the outflow of water from the water recirculation system. Therefore, according to one specific embodiment of the present invention, the system also comprises a flow meter arranged in the recirculation loop, said flow meter being connected to the data processing unit. This flow meter may be a regular so called in-line measuring device. Moreover, it is suitably arranged close to a user outflow, e.g. close to a shower head in a recirculating shower. In this context, the present invention also refers to a method comprising comparing or calculating the relationship between an outflow value obtained in the flow meter arranged in the recirculation loop in a system according to the present invention and an inflow to the water tank obtained by water level detection/estimation in the water tank. As hinted above, this may be a way to control and regulate the system. Furthermore, this may also be the foundation to calculate other interesting parameters, such as recirculation degree, cost savings etc. etc. Moreover, the difference between these values may also drive the regulation. Therefore, according to one specific embodiment, the data processing unit is a control unit for the system according to the present invention and wherein the difference of the outflow value from the flow meter arranged in the

recirculation loop and the inflow value to the water tank obtained by water level estimation in the water tank drives the regulation of the inflow of water from the fresh water inlet to the water tank.

Detailed description of the drawings

In fig. 1 there is shown one part of a system 1 according to the present invention. As it is only a part of the system 1 , the reference number 1 is provided in parenthesis. This part (1 ) of the system comprises a water tank 200 and a fresh water inlet 300 being connected to the water tank 200.

Moreover, an air gap (see as dotted line in figs. 1 and 2) is provided between the fresh water inlet 300 and the maximum water level in the water tank 200. Furthermore, according to this specific embodiment there is provided a mesh 400 with an outflow 500 being arranged at a distance from the bottom 700 of the water tank 200. Moreover, the outflow 500 of the mesh 400 is also positioned at a cross sectional distance from a water tank outflow 600.

Furthermore, in this embodiment there are 7 sensors arranged in the water tank 200, but a lower number is also possible, e.g. 4 sensors, typically EC sensors. There is first of all a minimum level sensor minLS and also a maximum level sensor maxLS arranged in the water tank 200. Moreover, in this case emergency sensors EmaxLS and EminLS are also arranged in the water tank 200.

In fig. 2 there is shown one specific embodiment according to the present invention, which is in line with the one shown in fig. 1 , however in this case a measurement rod 1000 is provided inside of the water tank 200.

Suitably, the sensors are provided fixated on the measurement rod 1000. In this case there are also 7 sensors. Furthermore, suitably the measurement rod 1000 is fixated in the water tank outlet 600. This may be arranged so that an end fixation extension of the measurement rod 1000 is arranged to be fitted and fixated into the water tank outflow 600. This may also function as preventing vortex formation out from the water tank outflow 600. Furthermore, the measurement rod 1000 may also be fixated in the top of the water tank 200.

In fig. 3 there is shown one measurement rod 1000 according to one embodiment of the present invention. In this case there is a total of 8 sensors arranged along the measurement rod 1000. These sensors suitable are conductivity sensors, i.e. electrodes. As notable, in the bottom there is arranged one electrode pair where two electrodes are arranged beside each other. Above these electrodes only single electrodes are arranged at all different water measurement levels. This type of configuration implies using level sensors being connected to a micro controller with an analogue to digital converter (ADC). Moreover, as electrodes are used, the method used also involves a discharge sequence when the software sequence is performed.

A second aspect of the present invention

Below there is provided a second aspect of the present invention.

According to the broadest perspective of this aspect there is provided an air gap unit intended for a water distribution system.

Technical Background related to this second aspect

In different types of water distribution systems, air gaps may be a requirement to ensure that contaminated water cannot flow back into a fresh water supply. The present invention according to this second aspect refers to an air gap unit intended for water distribution systems where an air gap is a requirement.

According to this second aspect the present invention is directed to providing an improved air gap unit which ensures that a minimal level of air bubbles enter into the water flow provided after the air gap unit.

Summary of second aspect of the present invention

The stated purpose above is achieved by an air gap unit intended for a water distribution system, said air gap unit comprising a water inlet, an air gap and an air gap tank with a water outlet, wherein the air gap tank comprises a channel leading the water flow inside of the air gap tank, from one position to another position closer to a bottom of the air gap tank and wherein the channel is arranged to change the water flow direction in at least one position, said change of the water flow direction being to a more horizontal direction and/or a direction more upwards directed away from the bottom of the air gap tank.

The channel, its arrangement and thus direction from the receiving part of the channel until an end position where the water flows out are key aspects according to the present invention. This is important in relation to ensure that a minimal number of air bubbles is created and part of the water outflow from the air gap unit and into the rest of the water distribution unit. Air into such a water flow causes several problems, such as problems with reference to measuring and pumping etc. Therefore, it is a key aspect to minimize this risk. Furthermore, the air gap unit and thus channel must also enable to deliver a sufficiently high water flow so that the air gap unit is not a minimizing unit in this regard.

The arrangement according to the second aspect of the present invention where the channel is arranged to change the water flow direction in at least one position, said change of the water flow direction being to a more horizontal direction and/or a direction more upwards directed away from the bottom of the air gap tank is a first level of feature according to the present invention to ensure that a sufficiently flow level can be maintained but where the number of air bubbles formed is suppressed.

The concept according to the present invention ensures that the flow rate of water through the tank is decreased at the right place(s). Moreover, by decreasing the water flow according to the present invention this also ensures the right type of flow through the tank. The above ensures that air bubble formation is suppressed and that a controlled flow is provided out from the tank. As further described below, the water flow direction is preferably shifted so that the water flow is sent in a lateral direction. Furthermore, the water flow is preferably also shifted so that the lateral direction is in an opposite direction in comparison to the outflow from the water tank.

As may be understood from below, there are also other advantages provided with the solution according to the second aspect of the present invention. First of all, the entire (air gap) water tank may be produced in one single unit. This has both production and user benefits. Secondly, although the tank may be produced as one single unit and with the provision of shift in water flow rate and direction, the water flow output from the water tank may still be kept at the intended level. Yet another advantage is that the system may be emptied based only on gravity, i.e. as a regular tank, although the tank is provided with means for changing the water flow rate and direction at the intended position(s).

Specific embodiments of the second aspect of the present invention

Below some specific embodiments of the second aspect of the present invention are disclosed and further explained. According to one embodiment of the second aspect of the present invention, the channel comprises a final bent free from sharp edges, said final bent extending in an end of the channel. One possible such final bent and channel end is shown in fig. 5. By providing this type of bent, the water flow direction is changed. The water outflow from the channel is directed away from water outlet of the air gap unit and air gap tank. This enables both to minimize the number of air bubbles formed but also ensures that the water flow out from the channel is not directly flown out from the air gap tank from the water outlet.

According to one specific embodiment of the second aspect of the present invention, the final bent is bent at least 45 degrees when measured from a totally vertical direction, preferably at least 60 degrees. This is measured as an average over the entire bent from start to the end of the bent. Furthermore, preferably the bent is not bent more than 90 degrees. This is of interest as it is preferable to enable to empty the channels in a simple way and avoid water to be standing in the channel after an inlet / outlet cycle.

Furthermore, according to yet another embodiment of the present invention, according to a second aspect, there is arranged a drop-shaped portion at the end of the channel. One possible such solution is shown in figs. 5-6. The drop-shaped portion ensures a smooth lift of the water. If the edge of the end is too sharp then this creates turbulence and thus bubble formation. Therefore, by having the drop-shaped portion the turbulence is lowered.

Furthermore, the air bubble still being formed are driven towards the top. Moreover, the few air bubbles still coming around the end wants to follow the wall on the backside of the channel to also be driven towards the top. In this regard, of a too sharp end is implemented instead, then air bubbles coming around the end will instead not follow the backside wall and will be able to come down into the outflow from the air gap tank.

According to one specific embodiment of the second aspect of the present invention, the channel comprises multiple bents which bents bent from a more vertical direction towards a more horizontal direction. The water flow speed will decrease in the bents. This as such decreases the air bubble formation. Moreover, the channel may be arranged in a“snake-like” shape so that the bents are directed in opposite ways, one by one, along the channel. One such solution is shown in figs. 5-6.

Moreover, according to yet another specific embodiment of the second aspect of the present invention, the channel is arranged continuously through the entire air gap tank, from one wall side to the other wall side of the air gap tank. This implies that the channel also constitutes the wall of the air gap tank. Furthermore, according to yet another specific embodiment, the air gap tank is made in one piece with the channel arranged continuously through the entire air gap tank, from one wall side to the other wall side of the air gap tank.

Furthermore, and as mentioned, according to one specific embodiment of the second aspect of the present invention, the water outlet is arranged at a distance from the end of the channel. Moreover, according to another embodiment, the water outlet is arranged in an opposite position in

comparison to the outflow direction of the end of the channel, when viewing a cross section of the air gap tank. One such alternative is shown in figs. 5-6.

Furthermore, the air gap unit may also comprise other features and properties of importance. According to one specific embodiment, the air gap unit comprises a radar sensor intended for water level detection in the air gap tank. It should be noted that also other sensors are totally possible, such as for detection of one or more water quality parameters, such as further explained below. In line with this, according to one specific embodiment of the present invention, at least one sensor directed to measure a water quality parameter is arranged in the air gap tank. Non-limiting examples of such water quality parameters may be to measure the content of certain

components, such as TOC (total organic content), the hardness of the water, pH, the level of certain components, such as e.g. the level of heavy metals, etc. etc.

Furthermore, the air gap unit also comprises some kind of inlet where the fresh water is flowed in. It is also from this inlet the actual air gap is provided. The inlet may be provided in different forms. The inlet may be provided only as one single chamber. According to one embodiment, however, then multiple inlet channels are used. All alternatives are possible according to the present invention, i.e. only one single inlet chamber, one chamber extending into multiple outflow channels, or the other way around, or only multiple outflow channels. Therefore, according to one specific

embodiment of the second aspect of the present invention, the water inlet is arranged with a nozzle having multiple channels. These multiple channels ensure to increase the laminar flow effect in the water flow entering into the channel. As such, the present invention provides an air gap unit where comparatively a laminar water flow enters into the channel with a geometry that ensures to drive a low level of air bubble formation and where the air bubbles still being formed are driven towards the top instead of to the water outflow in the bottom of the air gap tank. This further implies that the air bubbles being formed will disappear and never be able to enter tie outflow of the air gap tank.

Furthermore, also other means may be arranged as part of the system according to the second aspect of the present invention. According to one specific embodiment, the nozzle comprises a flow restrictor. Such a flow restrictor may be provided to ensure to meet certain requirements in some countries. This is also true for the actual air gap as such. According to one specific embodiment of the present invention, the air gap is at least 20 mm. This is also a suitable lowest level and in several cases the air gap is suitably larger than this.

Furthermore, the present invention is also directed to a water distribution system comprising an air gap unit according to the second aspect of the present invention. According to yet another embodiment, the water distribution system is a shower, sink, washing machine, or a dishwasher. The water distribution system may be such intended for domestic usage, but also industrial shower systems, washing machine systems, or dishwasher system are totally possible.

According to yet another embodiment of the second aspect of the present invention, said water distribution system is a water recirculation system allowing for purification and recycling of water or separation of water based on measurement of water quality in the water recirculation system.

Also in this case, showers, sinks washing machines, or dishwashers or system therefore are totally possible. It should also be noted that systems comprising several units, such as several showers, or different type of units, e.g. a connected shower and a sink in the same system, are possible according to the present invention. According to one specific embodiment, said water recirculation system is a recirculating shower.

It should be noted that the air gap tank according to the second aspect of the present invention suitable also has measuring capabilities. Fresh water is flown into the air gap tank. This implies that the air gap tank is a suitable point where the fresh water is measured and analyzed. Moreover, as some water normally is remaining in the air gap tank also after inlet mode, such as in e.g. a recirculating shower, it is suitable to measure here. This volume is not flowing but instead standing still and therefore an analysis of this volume is quite simple to perform.

The measurements may be directed to different parameters, and different forms of water quality indicators are of interest. Non-limiting examples are water quality parameters, such as the content of organic substances and content of polymeric substances or heavy metals. Another possibility is to measure certain bacteria or the like, such as Legionella. Other parameters of possible interest are pH and water hardness.

The technology to use may vary and non-limiting examples are impedance with frequency sweeping, another type of spectroscopy or laser, conductivity or turbidity measurements, or the like. Furthermore, several different types of sensors may be suitable to use. Moreover, sensors having several capabilities are of course of interest to implement.

Detailed description of the drawings referring to a second aspect of the present invention

Below, the figures are described. In fig. 4 there is shown an air gap unit A1 according to one specific embodiment of the present invention, intended for a water distribution system A2 (one part thereof is shown in fig. 4). The air gap unit A1 comprises a water inlet A3, an air gap A4 and an air gap tank A5 with a water outlet A20. As shown in figs. 5 and 6, the air gap tank A5 comprises a channel A6 leading the water flow inside of the air gap tank A5, from one position A7 to another position closer to a bottom A8 of the air gap tank A5 and wherein the channel A6 is arranged to change the water flow direction in at least one position, said change of the water flow direction being to a more horizontal direction and/or a direction more upwards directed away from the bottom of the air gap tank A5. As may be seen in figs. 5 and 6, the channel A6 comprises a final bent A9 free from sharp edges, and where the final bent A9 extends in an end A10 of the channel A6. Moreover, there is also arranged a drop-shaped portion A11 at the end A10 of the channel A6. Furthermore, the channel A6 comprises multiple bents A9, A12 which bents A9, A12 bent from a more vertical direction towards a more horizontal direction. This creates the“snake” or“saxophone” shape of the channel.

Moreover, regarding the water outlet A20 it may also be said that also here there may additional means to ensure that no air enters into the system. To provide a tight connection between water outlet A20 and the tube to the sucking pump is important. No air should be possible to suck into the system at this point. According to one specific embodiment of the present invention there is provided a clickable function, e.g. clickable means, on the end of the water outlet 20. This clickable means is possible to connect to a seal unit, with O rings or the like, to ensure a tight sealing from the air gap tank A5 to the sucking pump.

In figs. 5 and 6, there are shown one specific embodiment of the channel 6 according to the present invention, seen in a cross sectional view. Here it is also clearly seen that the water outlet A20 is arranged in an opposite position in comparison to the outflow direction of the end A10 of the channel A6, when viewing a cross section of the air gap tank 5. In fig. 6 there is also shown one embodiment of a water inlet A3 where the water inlet A3 is arranged with a nozzle A40 having multiple outlet channels A41.

Moreover, in fig. 7 there is shown one embodiment of the present invention, when viewed from above. Here the air gap tank A5 and channel A6 is seen from above. In area (a) water is flowed into the air gap tank A5. Area (b) is a space where the formed air bubbles are bubbled up. As can be seen, this is suitably located in an area away from the water outlet A20, which is shown as area (c). Furthermore, area (d) depicts an intended possible radar measurement area where the water level may be measured. Clauses - a second aspect of the present invention

1. Air gap unit (A1 ) intended for a water distribution system (A2), said air gap unit (A1 ) comprising a water inlet (A3), an air gap (A4) and an air gap tank (A5) with a water outlet (A20), wherein the air gap tank (A5) comprises a channel (A6) leading the water flow inside of the air gap tank (A5), from one position (A7) to another position closer to a bottom (A8) of the air gap tank (A5) and wherein the channel (A6) is arranged to change the water flow direction in at least one position, said change of the water flow direction being to a more horizontal direction and/or a direction more upwards directed away from the bottom of the air gap tank (A5).

2. Air gap unit (1 ) according to claim 1 , wherein the channel (A6) comprises a final bent (A9) free from sharp edges, said final bent (A9) extending in an end (A10) of the channel (A6).

3. Air gap unit (A1 ) according to claim 2, wherein the final bent (A9) is bent at least 45 degrees when measured from a totally vertical direction, preferably at least 60 degrees.

4. Air gap unit (A1 ) according to claim 2 or 3, wherein there is arranged a drop-shaped portion (A11 ) at the end (A10) of the channel (A6).

5. Air gap unit (A1 ) according to any of the preceding claims, wherein the channel (A6) comprises multiple bents (A9, A12) which bents (A9, A12) bent from a more vertical direction towards a more horizontal direction.

6. Air gap unit (A1 ) according to any of the preceding claims, wherein the channel (A6) is arranged continuously through the entire air gap tank (A5), from one wall side to the other wall side of the air gap tank (A5). 7. Air gap unit (A1 ) according to any of the preceding claims, wherein the air gap tank (A5) is made in one piece with the channel (A6) arranged

continuously through the entire air gap tank (A5), from one wall side to the other wall side of the air gap tank (A5).

8. Air gap unit (A1 ) according to any of claims 2-7, wherein the water outlet (A20) is arranged at a distance from the end (A10) of the channel (A6).

9. Air gap unit (A1 ) according to claim 8, wherein the water outlet (A20) is arranged in an opposite position in comparison to the outflow direction of the end (A10) of the channel (A6), when viewing a cross section of the air gap tank (A5).

10. Air gap unit (A1 ) according to any of the preceding claims, also

comprising a radar sensor (A30) intended for water level detection in the air gap tank (A5).

11. Air gap unit (A1 ) according to any of the preceding claims, wherein at least one sensor directed to measure a water quality parameter is arranged in the air gap tank (A5).

12. Air gap unit (A1 ) according to any of the preceding claims, wherein the water inlet (A3) is arranged with a nozzle (A40) having multiple channels (A41 ).

13. Air gap unit (A1 ) according to claim 12, wherein the nozzle (A40) comprises a flow restrictor.

14. Water distribution system (A2) comprising an air gap unit (A1 ) according to any of claims 1 -13.

15. Water distribution system (A2) according to claim 14, wherein the water distribution system (2) is a shower, sink, washing machine, or a dishwasher. 16. Water distribution system (A2) according to claim 14 or 15, wherein said water distribution system (A2) is a water recirculation system allowing for purification and recycling of water or separation of water based on

measurement of water quality in the water recirculation system.

17. Water distribution system (A2) according to claim 16, wherein said water recirculation system is a recirculating shower.

18. Water distribution system (A2) according to any of the preceding claims, wherein the water distribution system (A2) allows for purification and recycling of water or separation of water, wherein said system allowing for purification and recycling of water or separation of water comprises a recirculation loop, a water tank (200, A1 ), a fresh water inlet (300) connected to the water tank (200, A1 ), a water treatment unit, a sensor system and a control system, wherein the sensor system gives input to the control system with respect to a selection decision of either recycling of water in the system or separation of water from the system in at least one separation point, wherein there is arranged an air gap between the fresh water inlet (300) and the maximum water level in the water tank (200, A1 ), wherein the water tank (200, A1 ) comprises multiple level sensors which are connected to a data processing unit for the water distribution system (A2), and wherein the data processing unit is arranged to register different levels in the water tank (200, A1 ) and/or to calculate inflow to the water tank (200, A1 ) based on water level estimation in said multiple level sensors.

19. Water distribution system (A2) according to claim 18, wherein the water tank (200, A1 ) comprises multiple level sensors which are connected to a data processing unit for the water distribution system (A2), and wherein the data processing unit is arranged to register different levels in the water tank (200, A1 ) and to calculate inflow to the water tank (200, A1 ) based on water level estimation in said multiple level sensors. A third aspect of the present invention

According to a third aspect of the present invention there is disclosed an air gap tank in a system mentioned above, wherein the level sensor is a radar sensor. According to this third aspect of the present invention there is disclosed a system allowing for purification and recycling of water or separation of water, wherein said system allowing for purification and recycling of water or separation of water comprises a recirculation loop, a water tank, a fresh water inlet connected to the water tank, a water treatment unit, a sensor system and a control system, wherein the sensor system gives input to the control system with respect to a selection decision of either recycling of water in the system or separation of water from the system in at least one separation point, wherein there is arranged an air gap between the fresh water inlet and the maximum water level in the water tank, wherein the water tank comprises a level sensor in the form of a radar sensor, said radar sensor being connected to a data processing unit for the system, and wherein the data processing unit is arranged to register a liquid level in the water tank and/or to calculate inflow to the water tank based on water level estimation from the radar sensor.

According to one specific embodiment of the present invention, the radar sensor is arranged to register different levels in the water tank.

Moreover, according to yet another specific embodiment, the data processing unit is arranged to calculate inflow to the water tank based on water level estimation from the radar sensor in different levels. Furthermore, according to one embodiment, the water tank comprises a minimum level (minL) which is set in the data processing unit. Moreover, the water tank may comprise a minimum level (minL) and a maximum level (maxL) which are set in the data processing unit.

According to yet another embodiment, the system comprises an air gap unit intended for a water distribution system, said air gap unit comprising a water inlet, an air gap and an air gap tank with a water outlet, wherein the air gap tank comprises a channel leading the water flow inside of the air gap tank, from one position to another position closer to a bottom of the air gap tank and wherein the channel is arranged to change the water flow direction in at least one position, said change of the water flow direction being to a more horizontal direction and/or a direction more upwards directed away from the bottom of the air gap tank.

According to another embodiment, wherein the channel comprises a final bent free from sharp edges, said final bent extending in an end of the channel.

According to yet another embodiment, wherein the final bent is bent at least 45 degrees when measured from a totally vertical direction, preferably at least 60 degrees.

Moreover, according to one embodiment, there is arranged a drop shaped portion at the end of the channel.

According to one embodiment, wherein the channel comprises multiple bents, which bents bent from a more vertical direction towards a more horizontal direction.

Furthermore, according to yet another embodiment, wherein the channel is arranged continuously through the entire air gap tank, from one wall side to the other wall side of the air gap tank.

According to one embodiment, the air gap tank is made in one piece with the channel arranged continuously through the entire air gap tank, from one wall side to the other wall side of the air gap tank.

Furthermore, the water outlet may be arranged at a distance from the end of the channel.

According to yet another embodiment, the water outlet is arranged in an opposite position in comparison to the outflow direction of the end of the channel, when viewing a cross section of the air gap tank.

Moreover, at least one sensor may be directed to measure a water quality parameter is arranged in the air gap tank.

According to one specific embodiment, the water inlet is arranged with a nozzle having multiple channels. The nozzle may comprise a flow restrictor.

According to a third aspect of the present invention there is disclosed a water distribution system comprising an air gap unit according to above.

Moreover, the water distribution system may be a shower, sink, washing machine, or a dishwasher. According to yet another embodiment, said water distribution system is a water recirculation system allowing for purification and recycling of water or separation of water based on measurement of water quality in the water recirculation system. Moreover, said water recirculation system may be a recirculating shower.

Clauses - a third aspect of the present invention

1 A system allowing for purification and recycling of water or separation of water, wherein said system allowing for purification and recycling of water or separation of water comprises a recirculation loop, a water tank, a fresh water inlet connected to the water tank, a water treatment unit, a sensor system and a control system, wherein the sensor system gives input to the control system with respect to a selection decision of either recycling of water in the system or separation of water from the system in at least one separation point, wherein there is arranged an air gap between the fresh water inlet and the maximum water level in the water tank, wherein the water tank comprises a level sensor in the form of a radar sensor, said radar sensor being connected to a data processing unit for the system, and wherein the data processing unit is arranged to register a liquid level in the water tank and/or to calculate inflow to the water tank based on water level estimation from the radar sensor.

2. The system according to claim 1 , wherein the radar sensor is arranged to register different levels in the water tank.

3. The system according to claim 2, wherein the data processing unit is arranged to calculate inflow to the water tank based on water level estimation from the radar sensor in different levels.

4. The system according to any of claims 1 -3, wherein the water tank comprises a minimum level (minL) which is set in the data processing unit.

5. The system according to any of claims 1 -4, wherein the water tank comprises a minimum level (minL) and a maximum level (maxL) which are set in the data processing unit.

6. The system according to any of claims 1 -5, wherein the system comprises an air gap unit (A1 ) intended for a water distribution system (A2), said air gap unit (A1 ) comprising a water inlet (A3), an air gap (A4) and an air gap tank (A5) with a water outlet (A20), wherein the air gap tank (A5) comprises a channel (A6) leading the water flow inside of the air gap tank (A5), from one position (A7) to another position closer to a bottom (A8) of the air gap tank (A5) and wherein the channel (A6) is arranged to change the water flow direction in at least one position, said change of the water flow direction being to a more horizontal direction and/or a direction more upwards directed away from the bottom of the air gap tank (A5).

7. The system according according to claim 6, wherein the channel (A6) comprises a final bent (A9) free from sharp edges, said final bent (A9) extending in an end (A10) of the channel (A6).

8. The system according to claim 7, wherein the final bent (A9) is bent at least 45 degrees when measured from a totally vertical direction, preferably at least 60 degrees.

9. The system according to claim 7 or 8, wherein there is arranged a drop shaped portion (A11 ) at the end (A10) of the channel (A6).

10. The system according to any of the preceding claims, wherein the channel (A6) comprises multiple bents (A9, A12) which bents (A9, A12) bent from a more vertical direction towards a more horizontal direction.

11. The system according to any of the preceding claims, wherein the channel (A6) is arranged continuously through the entire air gap tank (A5), from one wall side to the other wall side of the air gap tank (A5).

12. The system according to any of the preceding claims, wherein the air gap tank (A5) is made in one piece with the channel (A6) arranged continuously through the entire air gap tank (A5), from one wall side to the other wall side of the air gap tank (A5). 13. The system according to any of claims 6-12, wherein the water outlet (A20) is arranged at a distance from the end (A10) of the channel (A6).

14. The system according to claim 13, wherein the water outlet (A20) is arranged in an opposite position in comparison to the outflow direction of the end (A10) of the channel (A6), when viewing a cross section of the air gap tank (A5).

15. The system according to any of the preceding claims, wherein at least one sensor directed to measure a water quality parameter is arranged in the air gap tank (A5).

16. The system according to any of the preceding claims, wherein the water inlet (A3) is arranged with a nozzle (A40) having multiple channels (A41 ).

17. The system according to claim 16, wherein the nozzle (A40) comprises a flow restrictor.

18. Water distribution system (A2) comprising the system according to any of claims 1-17.

19. Water distribution system (A2) according to claim 18, wherein the water distribution system (A2) is a shower, sink, washing machine, or a dishwasher.

20. Water distribution system (A2) according to claim 18 or 19, wherein said water distribution system (A2) is a water recirculation system allowing for purification and recycling of water or separation of water based on

measurement of water quality in the water recirculation system. 21. Water distribution system (A2) according to claim 20, wherein said water recirculation system is a recirculating shower.

Claims

1. A system (1 ) allowing for purification and recycling of water or separation of water, wherein said system allowing for purification and recycling of water or separation of water comprises a recirculation loop, a water tank (200), a fresh water inlet (300) connected to the water tank (200), a water treatment unit, a sensor system and a control system, wherein the sensor system gives input to the control system with respect to a selection decision of either recycling of water in the system or separation of water from the system in at least one separation point, wherein there is arranged an air gap between the fresh water inlet (300) and the maximum water level in the water tank (200), wherein the water tank (200) comprises multiple level sensors which are connected to a data processing unit for the system (1 ), and wherein the data processing unit is arranged to register different levels in the water tank (200) and/or to calculate inflow to the water tank (200) based on water level estimation in said multiple level sensors.

2. The system (1 ) according to claim 1 , wherein the water tank (200) comprises multiple level sensors which are connected to a data processing unit for the system (1 ), and wherein the data processing unit is arranged to register different levels in the water tank (200) and to calculate inflow to the water tank (200) based on water level estimation in said multiple level sensors.

3. The system (1 ) according to claim 1 or 2, wherein the water tank (200) comprises at least four level sensors, preferably more than four level sensors.

4. The system (1 ) according to any of claims 1 -3, wherein the water tank (200) comprises a minimum level sensor (minLS).

5. The system (1 ) according to any of claims 1 -4, wherein the water tank (200) comprises a minimum level sensor (minLS) and a maximum level sensor (maxLS).

6. The system (1 ) according to any of claims 1 -5, wherein the multiple level sensors are conductivity sensors.

7. The system (1 ) according to any of claim 1 -5, wherein the multiple level sensors are arranged on a measurement rod (1000) which is possible to fixate in the water tank (200) at a given level.

8. The system (1 ) according to claim 7, wherein the measurement rod (1000) comprises an end fixation extension which is arranged to fit and fixate into a water tank outflow (600) of the water tank (200).

9. The system (1 ) according to any of the preceding claims, wherein the water tank outlet (600) is positioned off-center.

10. The system (1 ) according to any of claims 1 -9, wherein the fresh water inlet (300) is arranged to flow water into a mesh (400).

11. The system (1 ) according to claim 10, wherein the mesh (400) is monofilament yarn based.

12. The system (1 ) according to claim 10 or 11 , wherein the mesh openings of the mesh (400) are in the range of from 100 to 700 micron.

13. The system (1 ) according to any of claims 10-12, wherein an outflow (500) of the mesh (400) is positioned beneath the minimum water level in the water tank (200) implying that the outflow (500) of the mesh (400) is positioned beneath the water surface.

14. The system (1 ) according to any of claims 10-13, wherein an outflow (500) of the mesh (400) is positioned at a cross sectional distance from a water tank outflow (600).

15. The system (1 ) according to any of claims 10-14, wherein an outflow (500) of the mesh (400) has a distance to a bottom (700) of the water tank (200) of at least 60 mm.

16. The system (1 ) according to any of claims 10-15, wherein the system (1 ) comprises a water tank (200), a measurement rod (1000) and a mesh (400) which are all connectable to each other into one unit.

17. The system (1 ) according to any of the preceding claims, wherein the air gap is at least 20 mm.

18. The system (1 ) according to any of the preceding claims, said system also comprising a flow meter arranged in the recirculation loop, said flow meter being connected to the data processing unit.

19. The system (1 ) according to any of the preceding claims, wherein the water tank (200) comprises at least four level sensors, preferably more than four level sensors, more preferably at least six level sensors, optionally arranged along a measurement rod (1000), and wherein the level sensors are connected to a micro controller with an analogue to digital converter (ADC).

20. The system (1 ) according to claim 19, wherein two electrodes are arranged at a level 0, and wherein other electrodes are arranged individually at higher levels.

21. A measurement rod (1000) comprising at least four integrated level sensors, preferably more than four level sensors, more preferably at least six level sensors, which level sensors are positioned along the measurement rod (1000) and are connected to a micro controller with an analogue to digital converter (ADC).

22. The measurement rod (1000) according to claim 21 , wherein two electrodes are arranged at a level 0, and wherein other electrodes are arranged individually at higher levels.

23. A method for measuring level in the system according to any of claims 1 - 20 and/or with a measurement rod according to claim 21 or 22, wherein all measurements are performed using single electrodes above level 0 and wherein the method involves sending time passed and level to a control unit.

24. The method according to claim 23, wherein the method involves using conductivity sensor electrodes and measuring the conductivity between single electrodes above level 0.

25. A method comprising comparing or calculating relationship between an outflow value obtained in the flow meter arranged in the recirculation loop in a system according to any of claims 18-20 and an inflow to the water tank (200) obtained by level estimation in the water tank (200).

26. The method according to claim 25, wherein the data processing unit is a control unit for the system (1 ) and wherein the difference of the outflow value from the flow meter arranged in the recirculation loop and the inflow value to the water tank (200) obtained by level estimation in the water tank (200) drives the regulation of the inflow of water from the fresh water inlet (300) to the water tank (200).

27. A method involving using multiple conductivity sensors in a system (1 ) according to any of claims 1 -20 and/or a measurement rod (1000) according to claim 21 or 22 for measuring water level, fresh water inflow to and water quality of water in a water tank (200).