The invention relates to the field of devices for treating the human body, and in particular to a washing device and a water conditioning unit as described in the preamble of the corresponding independent claims.

Devices and methods for delivering additives to showerheads for application to the human body are known, for example from EP 2543779 A2, or WO 2007/062536 Al,

WO 2018/122163 Al discloses a facility for use in sanitation, with an outlet, comprising multiple sprayers. Each sprayer is supplied with water by an associated conduit and valve. One of the conduits comprises a mixer adding a consumable to the water in the conduit.

WO 2019/002584 Al discloses an apparatus for dispensing a mixture of a diluent and an additive for sanitation, cosmetic or cleaning applications wherein the additive is added to the diluent while the diluent is under pressure.

WO 2022/106600 A2 discloses a water conditioning unit providing water at different flow rates, with different spraying characteristics and with additives admixed to the water.

EP 2095880 Al discloses a showerhead with a central outlet with impinging jets supplied by an inner hose within an outer hose. The outer hose feeds a further outlet. The inner hose is under a higher pressure, and a safety valve blocks the outer hose in case of a leak in the inner hose.

US 8'490'891 discloses a showerhead and washing fluid supply device in which a delivery pipe for the washing fluid is arranged inside a water pipe leading from the supply device to the showerhead. The supply device comprises a piston generating a pressure to deliver the washing fluid via its pipe to the showerhead. The piston is activated by the pressure of the mains water. In the showerhead, a manually operated pair of valves allows to switch between a delivery of water or of a foamy mixture of water, washing fluid and air. This mixture is generated in the showerhead and exits the showerhead at another outlet than the water. It is not possible to control the volume of the washing fluid that is dispensed, or its concentration within the mixture. The valve system in the showerhead is mechanically complex and must be operated by hand.

US 2007/235091 shows a water tap for kitchen sinks with two ports for connection to cold and hot water supply lines, and a third port for connection to a special-water supply line, e.g., for supplying filtered or carbonated water. A control valve selects whether mixed-water or special-water is fed to the water discharge head, using two concentric hoses.

WO 2007/004050 shows the separate delivery of treated and mains water, comprising a flexible hose for the separate conveyance of treated water and mains water for connection between a spray head provided with at two separate delivery points and a distribution unit for the separate supply of treated water and mains water.

EP 0 313 913 A2 discloses a mixing device in a showerhead, with a base unit with pumps, remotely controlled by buttons on the showerhead. An additive conduit can run in parallel to a water conduit leading to the showerhead, so that the additive is dispensed at the front of the showerhead, through a valve.

WO 2018/122223 Al and WO 2018/122206 Al disclose devices and methods for dispensing mixtures of water with additives, via a showerhead, and parameters associated with users of the devices.

US 2013/0291947 Al discloses a water tap with an additive conduit leading, in parallel to a water conduit, to a mixer at the outlet of the tap.

KR 20030008504 A shows a showerhead with control buttons, for controlling delivery of additives through a control and mixing box. The additives are provided by a set of additive containers.

It is a possible object of the invention to create a washing device and a water conditioning unit of the type mentioned initially with improved hygienic properties.

It is a possible object of the invention to create a washing device and a water conditioning unit of the type mentioned initially with a simpler structure.

At least one of these objects is accomplished by a washing device and a water conditioning unit according to the corresponding independent claims.

The washing device comprises a water conditioning unit, and the washing device is configured to provide, controlled by a user, water at different flow rates and with different spraying characteristics and with one or more additives admixed to the water.

The water conditioning unit comprises • a variable delivery element, in particular a proportional valve, for delivering water to an outlet at a flow rate that is controlled by the variable delivery element;

• a main channel through which the water is delivered by the variable delivery element;

• an admixing section of the main channel, for adding one or more additives to water flowing in the main channel;

• wherein the variable delivery element is arranged in the main channel before the admixing section.

The effect is that additives from the admixing section are added after the variable delivery element, and thus cannot contaminate or foul the variable delivery element. The variable delivery element can be a pump or a valve with variable flow. If the variable delivery element were arranged after the admixing section, additives such as soap, toning agents or colouring agents, oxidisers, catalysts etc. used for body or hair care can potentially accumulate at the variable valve or pump.

In embodiments, the water conditioning unit comprises a junction at which a flow from the main channel is split into at least a first outlet conduit and a second outlet conduit,

• the first outlet conduit being a mixture conduit,

• the second outlet conduit being a main conduit, with a main outlet valve arranged to control a flow of water from the main channel to the main conduit, preferably wherein the main outlet valve is a two-state valve.

This allows to shut off the flow through the main conduit, leaving only the mixture conduit open for the flow through the main channel. A total outflow dispensed by an outlet of the washing device is reduced accordingly. In embodiments, the main outlet valve is a two-state valve. That is, it can only be controlled to be fully open or fully closed, as opposed to a proportional valve. In embodiments, the mixture conduit is free from a valve.

This allows for a simple construction of the water conditioning unit, keeping the ability to vary the characteristics of the flow dispensed by separate sub-outlets with a single valve, that is, with the main outlet valve. In this way, it is possible to switch between spraying characteristics of two main operating modes, a first operating mode in which only one sub-outlet of the outlet is active, and a second operating mode in which two sub-outlets of the outlet are active. Furthermore, in the second operating mode, water flows through the mixture conduit, and any additives remaining in the mixture conduit are flushed away. This prevents or reduces soiling or fouling, in particular by bacteria, in the mixture conduit.

In embodiments, the mixture conduit leads to a mixture outlet of an outlet and the main conduit leads to a main outlet of the outlet. In particular, it can be the case that for a same pressure at the junction, the main outlet has a flow rate that is at least twice, in particular at least three times a flow rate of the mixture outlet.

This allows to switch between different operating modes having different flow rates and different spray characteristics. In a configuration in which there is no valve in the mixture conduit, if the main outlet valve is open, the total outflow is the sum of the flows through the mixture conduit and main conduit. If the main outlet valve is closed, the total outflow is the flow through the mixture conduit.

A typical value for pressure at which the ratio between the flow rates is defined is three bar.

In embodiments, the mixture conduit and mixture conduit are arranged together as part of a common hose. The two conduits thus run in parallel from the water conditioning unit to the dispensing unit. The two conduits can be separate flexible tubes arranged within a common hose or tube, which can be a fabric tube. Alternatively, one of the two conduits can be arranged within the other. This allows to handle the two conduits as a single hose.

In embodiments, the washing device comprises a bypass channel leading from a section of the main channel before the variable delivery element to a section of the main channel after the variable delivery element, with a bypass valve arranged in the bypass channel, wherein the bypass valve is a normally closed valve, and further in particular wherein the bypass valve is manually openable.

This allows to bypass the main channel with a flow through the bypass channel in the event that flow through the main channel is blocked. The bypass valve can be manually opened in such a situation, allowing at least to dispense water through the outlet, e.g., for rinsing a subject being treated with the washing device. Thus, even in the event of a malfunction or loss of electrical power it is possible to at least rinse away additives applied to a subject.

"Normally open" means that when not powered, the valve is open, that is, it allows the liquid to flow through, "Normally closed" means that when not powered, the valve is closed, that is, it blocks a flow of liquid.

In embodiments, the variable delivery element is a normally closed valve or pump and the main outlet valve is a normally open valve.

Consequently, in a situation where the washing device loses power, the variable delivery element will block flow through the main channel, and the main outlet valve will be open to the flow through the main conduit. When the bypass valve is manually opened, a rinsing operation can take place through the main conduit, with its typically higher flow rate.

In embodiments, the washing device comprises a temperature control stage with a hot water inlet and a cold-water inlet and for delivering water to the main channel, and wherein

• either the temperature control stage comprises a thermostatic mixer;

• or the temperature control stage comprises the proportional valve arranged to control a flow of cold water and a further proportional valve arranged to control a flow of hot water into the main channel.

If the washing device does not comprise a temperature control stage, it usually is supplied via an inlet with an inlet flow of water at a desired temperature. This inlet flow can be delivered from a manually operated faucet that allows to set the water's temperature, e.g,, by mixing water from a cold and a hot water supply. If the washing device comprises a temperature control stage, a hot and a cold water supply can be connected to the inlet, which then comprises two conduits, and the mixing takes place in the water conditioning unit, and can be automatically controlled within the water conditioning unit. Controlling the mixing can be done with a thermostatic mixer or separate hot and cold water valves, in accordance with a measurement of a temperature of the mixture.

The water conditioning unit is configured to provide, controlled by a user, water at different flow rates and at different outlet fittings and with one or more additives admixed to the water, the water conditioning unit comprising a variable delivery element, in particular a proportional valve, for delivering water to an outlet at a flow rate that is controlled by the variable delivery element; • a main channel through which the water is delivered by the variable delivery element;

• an admixing section of the main channel, for adding one or more additives to water flowing in the main channel;

• wherein the variable delivery element is arranged in the main channel before the admixing section.

The method is for operating a water conditioning unit to provide, controlled by a user, water at different flow rates and at different outlet fittings and with one or more additives admixed to the water, the water conditioning unit comprising

• a variable delivery element, in particular a proportional valve, for delivering water to an outlet at a flow rate that is controlled by the variable delivery element;

• a main channel through which the water is delivered by the variable delivery element;

• an admixing section of the main channel, for adding one or more additives to water flowing in the main channel;

The method comprises the steps of:

• operating the water conditioning unit in a first operating mode by o controlling the variable delivery element to operate at a first flow rate, o adding at least one additive to the water, and o delivering a mixture of water and the at least one additive only through a mixture conduit;

• operating the water conditioning unit in a second operating mode by o controlling the variable delivery element to operate at a second flow rate that is higher than the first flow rate, in particular at least four times as high, o not adding any additive to the water, and o delivering the water through both the mixture conduit and a main conduit that is separate from the mixture conduit.

In embodiments, the method comprises the step of

• operating the water conditioning unit in a third operating mode by, in the event that a flow through the main channel is impeded, delivering water through a bypass channel controlled by a manually operable bypass valve to bypass the main channel; and in particular to further deliver the water from the bypass channel through both the mixture conduit and the main conduit.

In embodiments, when switching between the first and second operation mode, the switching between delivering the mixture or the water through only the mixture conduit or both the mixture conduit and the main conduit is effected by opening and closing a main outlet valve in the main conduit.

According to an aspect of the invention, the variable delivery element is not necessarily arranged in the main channel before the admixing section.

In embodiments, the unit so far designated as water conditioning unit is used with a base fluid other than water. It can therefore more generally be considered a liquid conditioning unit, with the same structure and functions as the water conditioning unit described herein.

Further embodiments are evident from the dependent patent claims. Features of the method claims may be combined with features of the device claims and vice versa.

The subject matter of the invention will be explained in more detail in the following text with reference to exemplary embodiments which are illustrated in the attached drawing, which schematically shows: Figure 1 a hydraulic structure of a washing device.

In principle, identical or functionally identical parts are provided with the same reference symbols in the figures.

Figure 1 schematically shows a structure of flow paths through the washing device 10. Water from a water supply, for example a mains water supply and via a faucet 1, enters the washing device 10 through an inlet fitting 11. It splits, at a branching point 223, into a main water path through a main channel 22 and a bypass water channel 24. The flow in the bypass water channel 24 is controlled by a bypass valve 20, On the main water path, an optional inlet one way valve and/or an optional pressure elevating pump can be present (not illustrated). The water passes through a flow meter 16, or, alternatively, a parallel arrangement (not illustrated) of a flow meter and an internal bypass. Subsequently the flow optionally passes through a pressure reducer 18. The optional pressure reducer 18 acts as a flow limiter, so that the flow rate through the subsequent elements is independent of a mains water pressure, in settings where no pressure elevating pump is present. A pressure sensor 15 can be arranged to measure the water pressure, transmitting measurement values to a controller 100. The flow of water passes into an admixing section 224 of the main channel 22, controlled by a variable delivery element. The variable delivery element can be a variable pump, or, as in the remainder of the present description, a proportional valve 19. That means that it can be controlled to be kept in an opened state in which it is open to less than a maximum degree of opening. In its opened state it can be open to a degree between ten or twenty and a hundred percent of a maximum degree of opening.

In the admixing section 224, the flow is joined by one or more additive flows. In a mixing mode of operation, the proportional valve 19 reduces the flow of water. Simultaneously, each of one or more additive flows is delivered by an associated dosing pump, in particular a peristaltic pump 26 from an associated additive container 25 into the main channel 22 through an associated additive check valve 27, The additive check valve 27 can be a duck bill valve. In embodiments, the additive check valve 27 is not present. Following the admixing section 224, the flow - now optionally comprising one or more additives, depending on operation of the dosing or peristaltic pumps 26 - passes into a junction 30. At the junction 30, the admixing channel 22 reunites with the bypass channel 24, forming a reunited flow.

A temperature sensor 31 can be present after the admixing section 224, transmitting temperature measurement values to the controller 100.

The reunited flow is split up into a mixture conduit 331 and main conduit 332. These two conduits lead, via an outlet fitting 32, to an outlet 34. The outlet fitting 32 can comprise a single mechanical element establishing two fluid connections, or two separate mechanical elements, one for the mixture conduit 331 and one for the main conduit 332. The mixture conduit 331 and main conduit 332 can be guided through a common hose 33 such as a fabric hose. The outlet 34 typically is a showerhead. Fluid passing through the mixture conduit 331 is output, typically as a spray, through a mixture outlet 37. Fluid passing through the main conduit 332 is output through a main outlet 38. The mixture outlet 37 and main outlet 38 are sub-outlets of the same outlet 34 or shower head.

For situations in which a high flow of water is required, the main outlet 38 is arranged to dispense water at a significantly higher flow rate than the mixture outlet 37. The main outlet 38 can comprise a ring-like outlet opening surrounding an outlet opening of the mixture outlet 37.

The elements between the inlet fitting 11 and outlet fitting 32 constitute a water conditioning unit 2. The hose 33 and showerhead 34 form a dispensing unit 3. The water conditioning unit 2 comprises a controller 100 arranged to read sensor values, to read the state from user input elements (described below), to control actuators such as the valves and pumps in accordance with such sensor or user inputs, and to display information to the user. The controller 100 can further be configured to communicate with an external computer system. Communication can comprise sending operating data to the external computer system and receiving operating parameters, including user and client preferences, from the external system. Operating data can comprise measurements made by sensors of the device, information on user actions, usage of additives, device status data, error messages etc. Such data can be used for improving operation of the washing device itself or a fleet of devices, for ordering replacement containers for additives, scheduling maintenance etc. The external computer can be operated by a manufacturer and/or supplier of additives, or by a user. In the latter case, the external computer can be a handheld computing device, and can implement a user interface or dashboard displaying information from the washing device 10 and allowing to control the washing device 10,

In embodiments, water flow into the water conditioning unit 2 is controlled by the faucet 1. In particular the temperature of the flow can be controlled by the faucet being a mixing faucet, in particular with a thermostatic function, that is, it controls the mixture of hot and cold water so as to keep the temperature of the mixture constant. In this way the washing device 10 can be combined with existing haircare installations, replacing an existing showerhead. Users operating the washing device 10 can keep their habit of controlling the temperature by means of the faucet 1. With regard to water flow, the faucet can be fully opened, with the flow being controlled by the proportional valve 19 alone. This is the usual case, when the water conditioning unit 2 operates under normal operating conditions.

Under normal operating conditions, the water conditioning unit 2 can be operated in at least two main operating modes (in addition to being turned off entirely). In a first operating mode, or mixing mode, the proportional valve 19 controls the flow rate through the main channel 22, and therefore also the flow rate out of the outlet 34, to be relatively low. One or more of the of the additives is pumped into the water in the admixing section 224. Concentration of the additive(s) is determined and can be controlled by the relation between the flow rate of the proportional valve 19 and the flow rate of the respective dosing or peristaltic pump 26. With the low flow rate of the water, as determined by the proportional valve 19, the concentration of the additive in the water can be relatively high. In the mixing mode, the main outlet valve 21 is closed, and so the entire flow passes through the mixture conduit 331 and the corresponding mixture outlet 37. The mixture outlet 37 is designed to create a spray of atomised liquid even at low flow rates. The mixture outlet 37 is configured to create a spray of water by creating two or more colliding jets of water. Methods and devices, in particular cartridges for generating such a spray are described, for example, in

• WO 2011/054120 A2

• WO 2011/054121 A2

• WO 2019/233958 Al

• WO 2020/070159 Al

The mixture outlet 37 thus generates a fine spray of water, optionally comprising an additive. This allows to apply the additive and perform effective wetting and rinsing operations using relatively little water. This in turn results in a smaller proportion of additive running off immediately, and thus in less waste and higher effectiveness.

In a second operating mode, or rinsing mode, the proportional valve 19 controls the flow rate through the main channel 22, and therefore also the flow rate out of the outlet 34, to be relatively high. No additives are pumped into the water in the admixing section 224. In the rinsing mode, the main outlet valve 21 is opened, and so the entire flow passes in parallel through both the mixture conduit 331 and the main conduit 332 and the corresponding mixture outlet 37 and main outlet 38. The main conduit 332 and main outlet 38 are designed to have a larger flow rate than the mixture conduit 331 and mixture outlet 37, for the same pressure at the junction 30, So, a main part of a total outflow of the outlet 34 is effected through the main outlet 38. The mixture outlet 37 contributes to this flow, and the total outflow can be used for rinsing, for example, a subject's body or hair. There is no need for a separate valve for controlling the flow through the mixture conduit 331. As the in the rinsing mode water without additives flows through the mixture conduit 331, it is rinsed from additives which otherwise may remain in the mixture conduit 331. Such remaining additives could interact with later applications of other additives and/or cause fouling of the mixture conduit 331, in particular by bacterial growth.

In a further operating mode, or spraying mode, the proportional valve 19 controls the flow rate through the main channel 22, and therefore also the flow rate out of the outlet 34, to be low or intermediate (that is, less than high). No additives are pumped into the water in the admixing section 224. In the spraying mode, the main outlet valve 21 is closed, and so the entire flow passes through the mixture conduit 331 and the corresponding mixture outlet 37. A spray of atomised water is created. It can be used, for example, to moisturise hair or a body part prior applying an additive.

In the operating modes presented so far, the total flow out of the outlet 34 is controlled by the proportional valve 19 and the main outlet valve 21.

In embodiments, the washing device 10 is configured, in the mixing mode, to have a flow rate through the mixture outlet 37, with additives, of between half a litre and one litre per minute, in particular 0,75 litres/minute +/- 20%. This flow rate can be controlled by the proportional valve 19, with the main outlet valve 21 being closed.

The mixing mode can be implemented as one of the following substates or admixing modes, or the washing device 10 can be configured, for at least one of the additives, to switch between two or more of the following admixing modes:

• continuous admixing: herein, the flow of the additive and the water is continuous. The flow rate of the additive can be approximately one third of a total flow comprising water and additive. The total flow can be between one and two litres per minute.

• pulsed additive admixing: herein, the flow of the additive is pulsed. This can be implemented by turning the corresponding additive pump on and off periodically. This allows to save additive and/or precisely dose the additive. This in turn allows to use a highly concentrated additive. The flow rate of the additive can be approximately one sixth of the total flow. The total flow can be between one and two litres per minute.

• pulsed water admixing: herein, the flow of the water is pulsed. This “pulsing” is a preferred mode of application for additives that serve for coloration or toning, because a higher concentration of the additive can be dispensed. This in turn results in a higher efficiency of the application of the additive. The pulsing of the water allows to decrease the total water flow dispensed. It still allows for sufficiently high flow to maintain the colliding jets in the spray outlet 37. The flow rate of the additive can be approximately one half of the total flow. The total flow can be between one half and 1.5 litres per minute.

Depending on the application of the washing device 10, the additives can be soap, or additives used in hair care. Such additives are toning agents, colorants, oxidants and catalysts.

In embodiments, the washing device 10 is configured, in the rinsing mode, to have a flow rate through the high-flow outlet 38 of between five and nine litres per minute, depending on the water pressure at the inlet fitting 11. In particular this flow rate can be, for an inlet pressure of

2 bar: 2 to 4 litres per minute, in particular 3 litres per minute +/- 20%;

2,5 bar: 3 to 5 litres per minute, in particular 4 litres per minute +/- 20%;

3 bar:4 to 6 litres per minute, in particular 5 litres per minute +/- 20%. This flow rate can be controlled by the proportional valve 19, with the main outlet valve 21 being opened.

In embodiments, the washing device 10 is configured, in the spraying mode, to have a flow rate through the mixture outlet 37, without additives, of between one and two litres per minute, in particular 1.5 litres/minute +/- 20%. This flow rate can be controlled by the proportional valve 19, with the main outlet valve 21 being closed.

Exceptional operating conditions can arise when one of the elements in the main channel 22 blocks the flow. This can be caused by a power failure, if the proportional valve 19 is a normally closed valve: then no water is delivered to the outlet 34 and it is not possible to terminate a treatment by rinsing away additives that were previously applied to e.g., a client's body or hair. In such a situation, a user of the water conditioning unit 2 can manually operate the bypass valve 20 to open it. As a result, via the bypass channel 24 water is provided to the junction 30 and to the outlet 34. This constitutes a third or bypass operating mode. If the main outlet valve 21 is a normally open valve, the water provided will flow through both the mixture conduit 331 and main conduit 332, resulting in the largest possible flow for rinsing.

In embodiments, not illustrated, hot and cold water supply lines pass via the inlet fitting 11 into the water conditioning unit 2, and mixing and temperature control is implemented within the water conditioning unit 2. In embodiments in which this is done with a thermostatic mixer, this mixer can be arranged following the inlet. In embodiments in which this is done with two valves, these valves jointly also take the role of the proportional valve 19, that is, to control, in addition to the temperature, the total flow through the main channel 22. A corresponding topology of the water flow can be created, starting with the topology of Fig. 1, by introducing a second proportional valve, optionally preceded by an associated second pressure reducer and associated second pressure sensor, and fed through a second inlet. The outflow of the second proportional valve joins that of the proportional valve 19 to flow through the flow meter 16 into the admixing section 224. The bypass channel 24 can remain connected to an inlet supplied with cold water.

While the invention has been described in present embodiments, it is distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practised within the scope of the claims.