Patent Description:
Specifically, the present disclosure relates to a water supply system having at least two groups of water consumers with corresponding number of water networks that are connected by a cross feed valve, as well as an aircraft having such water supply system.

Document <CIT> relates to an aircraft having: an aircraft fuselage, a cabin region formed in the aircraft fuselage, an underfloor region separated from the cabin region by a floor partition, and a fresh-water supply system. The fresh-water supply system has a fresh-water provision unit arranged in the underfloor region. The fresh-water supply system has multiple water extraction units which are each arranged in the cabin region, and a water line network branched off from the fresh-water provision unit and extending to the water extraction units. Each water extraction unit has a shut-off valve, a filter unit and a tapping point, which are coupled in series by means of water lines. Each filter unit has an exchangeable water filter with a first filter material designed for filtering particles out of the water flowing through the water filter and with a second filter material designed for softening the water flowing through the water filter.

Currently, potable water in an aircraft is provided to water consumers, such as a faucet, a toilet or a galley, in a pressurised water network. In order to avoid a failure of all water consumers at once, at least two water networks are installed supplying pressurised water to respective water consumers.

However, separate water networks increase the overall weight of the water supply system in the aircraft, for example, due to separate conveying devices for each water network. Thus, a trade-off between redundancies and weight comes with such water supply systems.

It is therefore an object of the present disclosure to improve current water supply systems.

This object is solved by the present invention as defined in the independent claim.

According to a first aspect to better understand the present disclosure, a water supply system for a plurality of water consumer units in an aircraft comprises a main tank configured to store a main supply of (potable) water, a main water pipe connected to an outlet of the main tank, and a plurality of water networks, each configured to conduct water from the main tank to at least one of the plurality of water consumer units. The plurality of water consumer units is partitioned in a first group of water consumer units and at least a second group of water consumer units.

Thus, the plurality of water consumer units can be provided with water, such as potable water, from a main tank. The grouping of the water consumers allows controlling redundancies in the aircraft. For instance, in case of a plurality of lavatories, each group of water consumers can comprise at least one lavatory, in order to still provide a lavatory even if one of the water networks fails.

Furthermore, each of the plurality of water networks comprises a conveying device configured to convey water to each water consumer unit of one of the groups. In other words, the water consumer units of one of the groups is supplied with water through one water network.

The water supply system further comprises a cross feed valve configured to fluidically connect or separate the plurality of water networks downstream of the conveying devices in the plurality of water networks. The cross feed valve can be in an open position or a closed position, wherein a fluid connection is achieved between the plurality of water networks, when the cross feed valve is in the open position, and a fluid separation of the plurality of water networks (the pipes of each network) is achieved, when the cross feed valve is in the closed position.

In an implementation variant, the cross feed valve can comprise one shut-off valve, wherein a first port of the valve is fluidically connected to a pipe of a first one of the plurality of water networks and a second port of the valve is fluidically connected to a pipe of a second one of the plurality of water networks. A port of the (cross feed) valve is to be understood as an inlet or an outlet of the valve, wherein the actual shutoff member of the valve is arranged between the two ports of the valve, i.e. between the inlet and the outlet of the valve. The use of a single shutoff valve simplifies the overall water supply system, facilitates a simple piping or ducting, and allows avoidance of dead ends in the piping or ducting.

In another implementation variant, the system can comprise one cross feed valve for each pair of water networks. This allows fluidly connecting all water networks with one another, particularly if more than two water networks are present in the system. This may include one cross feed valve for each possible pair of water networks, or a number of cross feed valves corresponds to the number of furcations from the main water pipe.

In a further implementation variant, each of the pipes of the first and second water network at the respective first and second port of the valve can run in an at least partially vertical direction allowing water to drain from the respective pipe by gravity. In other words, the pipes of the first and second water network adjacent to the cross feed valve are installed in the system in a manner that the pipes of both networks are substantially vertical to allow draining the pipes by gravity. As a mere example, the pipes of the first and second water network, where the valve fluidly connects both pipes, are installed in a direction having a vertical component sufficiently steep for water to run by gravity.

Alternatively or additionally, the pipes of the first and second water network adjacent to the cross feed valve are installed in the system in a manner that allows draining the pipes pneumatically. In other words, blowing air through the pipes pushes the water out of the pipe. Such arrangement allows a more horizontally arranged pipe compared to draining the pipe by gravity. It is to be understood that at least one of the pipes adjacent to the valve can be arranged horizontally.

Draining the water from the pipe/s can further be facilitated by providing pipes of small inner diameter (water conducting area). A small inner diameter means a diameter in the range of <NUM> to <NUM>, preferably <NUM> to <NUM>, most preferably <NUM>. This further reduces the overall weight of the water supply system.

Also alternatively or additionally, the cross feed valve can be installed in the system in a manner that the valve drains by gravity. As a mere example, the cross feed valve can have an inlet port and an outlet port, and both ports are arranged with a height difference, i.e. the valve is arranged in a direction having a vertical component. In other words, the cross feed valve itself is arranged at least partially vertical.

In yet a further implementation variant, each of the pipes of the first and second water network can be directly connected to the respective first and second port of the valve substantially without forming a dead end pipe when the valve is closed. Substantially without forming a dead end pipe means that the pipe of the first or second water network is directly connected to the respective port of the valve, so that no extra pipe or duct is required, which would otherwise form a dead end. It is to be understood that the direct connection between the pipe of the first or second water network and the respective port may include a short fitting or nipple, which is fluidly connected to the respective port of the valve. The short fitting or nipple may be implemented as a T-shaped fitting, wherein the branch of the T-shaped fitting directed to the port of the valve has a minimum possible length.

In any case, the cross feed valve connects the pipe branches of the respective water network without an actual furcation towards the cross feed valve. In other words, the distance between the respective pipe and the shutoff member of the cross feed valve is kept to a minimum, so that a dead end in the water network is substantially avoided. This prevents or at least significantly reduces any build-up of bacteria or the like, so that hygienic standards can be met. In addition, the flow of water through the respective pipe branch is not (significantly) deteriorated.

As a mere example, a pipe of the first and second water network may be provided with an opening in the skin or shell of the pipe, to which the port of the valve is fluidly connected, such as welded, adhered or the like. Alternatively or additionally, the shortest possible (T-shaped) fitting is attached to the pipe in a fluid tight manner.

In another implementation variant, the system can further comprise a controller configured to control the plurality of conveying devices and the cross feed valve. For example, the controller may be connected with each of the conveying devices and the cross feed valve by a signal, data and/or electric line, through which a corresponding signal is transmitted to control the respective conveying device or valve. It is to be understood that the conveying devices and the cross feed valve are further configured to receive such signal and to change their operating state. As a mere example, the controller may set a conveying speed of one or more of the conveying devices and/or may set an opening degree of the cross feed valve (wherein a closed valve corresponds to an opening degree of zero). The conveying devices and/or valve may either be equipped with a corresponding controller and/or motor to respond to the received signal.

Alternatively or additionally, the conveying devices and/or valve may be directly controlled by the controller, such as by a corresponding voltage or current provided by the controller to a motor or drive of a conveying device and/or valve.

In yet another implementation variant, the system can further comprise at least one sensor configured to determine a water supply requirement of at least one of the plurality of water consumer units and to transmit a signal indicating the water supply requirement to the controller. Such water supply requirement may correspond to a water level in a buffer tank of the respective water consumer unit, so that the controller may convey water to the water consumer unit to fill the buffer tank. Another water supply requirement may be measured by a sensor of a faucet or lavatory flushing system, indicating an opening degree of the faucet or flushing system corresponding to the amount of water required by the faucet or flushing system per unit time. The controller may then control conveying of a corresponding amount of water through the respective water network to the water consumer unit.

In a further implementation variant the controller can further be configured to control the cross feed valve and one or more of the conveying devices in a particular manner.

According to a first exemplary operating manner, the controller may close the cross feed valve and operate each of the plurality of conveying devices in a normal mode. A normal mode of a conveying device means that the conveying device is set to convey an amount of water currently required by the respective water network. The amount of water currently required by a water network means a sum of required water amounts of all water consumer units of the respective water network. This required amount of water may be predefined or may be set in dependence on sensor measurements. This operating manner reflects the operation in the majority of the cases, i.e. when the water supply system operates in a normal manner.

According to a second exemplary operating manner, the controller may open the cross feed valve and operate one of the plurality of conveying devices, to convey water to each of the water networks. This operating mode allows saving energy by operating only one conveying device. This operating mode may be applicable in case a reduced amount of water is required by all water consumer units of one water network or even all water consumer units of more than one water network (or all water networks). The reduced amount of required water can be determined, for example, if all buffer tanks of the water consumer units have reached a minimum fill level, and particularly when a maximum fill level in all buffer tanks has been reached.

In addition, this operating mode can also be used, if one of the conveying devices fails or erroneously cannot convey the required amount of water.

According to a third exemplary operating manner, the controller may open the cross feed valve and operate each of the plurality of conveying devices at a maximum conveying power, when a maximum water supply requirement is determined at one of the plurality of water consumer units. This operating mode can be referred to as a boost function. Such boost function may be necessary at the start-up of the system. For instance, at the beginning of each mission/flight, the buffer tanks of the water consumer units, particularly a large buffer tank of a galley, have to be filled up in a short time period. Since the lavatories are usually not in use at this time (e.g., no passengers are on board), the maximum conveying power may be used to fill up the buffer tanks. Furthermore, one of the water networks may include a greater number of galleys than another water network. In this case, the boost function may be used to provide more water to the one water network including more galleys. Furthermore, the boost function is likewise applicable, if it is determined that one or more water networks require more water than other water networks. For instance, it may occur that a specific passenger behaviour leads to a more frequent use of lavatories than other lavatories. Employing the boost function, the buffer tanks of the more frequently used lavatories can be refilled faster. Alternatively or additionally, the water network architecture may require employing the boost function. Due to longer pipes or different pipe diameters an associated water network may require more water than is conveyable by only the conveying device of this particular water network.

According to a fourth exemplary operating manner, the controller may open the cross feed valve and operate at least one of the plurality of conveying devices, in order to perform a cross-check of sensors in the water networks. For instance, a comparison of sensor measurement (flow, pressure or the like) from one water network (sub-system) with another water network (sub-system) may be performed by conveying water with different conveying devices, one at a time. It is likewise possible that leak detection may fail in one of the water networks due to a sensor failure. By opening the cross feed valve, such leak detection may still be performed in this operating mode.

According to a fifth exemplary operating manner, the controller may close the cross feed valve, if a leakage is determined in one of the water networks. In other words, one water network, where a leakage has been detected, can be isolated from the entire water supply system. The remaining water networks and associated water consumer units can still be used. The cross feed valve even allows using the conveying device usually associated with the water network having the leakage for any other water network. In the latter case, a shut-off valve in the leaking water network downstream of the cross feed valve facilitates this use of the conveying device.

According to a sixth exemplary operating manner, the controller may open the cross feed valve in a system comprising more than one main tank, such as a dual water supply system having one main tank for one or more water networks on one side of the aircraft (e.g. left side or front) and having one main tank for one or more water networks on another side of the aircraft ( e.g. right side or back). In this case, the controller may control the cross feed valve and/ or a conveying device to convey water to each of the water networks in such a manner that both main tanks will have an equal water level and/or from one main tank to another main tank.

Furthermore, in such dual water supply system draining the water from the water networks may be achieved pneumatically. In this case, the cross feed valve should initially be closed in order to drain each side of the system individually. Towards the end of the drainage process, the cross feed valve can be opened in order to achieve a targeted pneumatic drainage of the valve and the cross feed link. This achieves a minimal residual water after draining and, hence, a minimal risk of freezing / blocking the associated pipes and valves.

In yet a further implementation variant, the system can further comprise at least one furcation dividing the main water pipe in a plurality of pipe branches. Each of the plurality of water networks branches off the main water pipe at one of the at least one furcation. In addition, each conveying device can be arranged in a respective one of the pipe branches downstream of a respective one of the at least one furcation. In other words, each water network begins at an associated furcation and has one conveying device.

A furcation can simply be implemented as at least one T-shaped fitting dividing the main water pipe into at least two branches. It is to be understood that any kind of branch-off may be implemented to form a furcation.

In case of more than two pipe branches and, hence, more than two water networks, the system can comprise one cross feed valve for each pair of water networks. In other words, a system with N pipe branches (i.e., N water networks) can have N-<NUM> cross feed valves.

According to a second aspect to better understand the present disclosure, an aircraft comprises the water supply system according to the first aspect or one of its variants.

In an implementation variant, the plurality of water consumer units can comprise one or more lavatories and one or more galleys of the aircraft. The lavatories and/or galleys may be distributed throughout the water networks. In other words, each water network can comprise one or more lavatories and/or one or more galleys.

In another implementation variant, when the water supply system comprises the controller, the water supply system can further comprise an aircraft data network configured to communicate with the controller. The aircraft data network may be a data network receiving and/or collecting sensor data of particular units of the aircraft, such as the water consumer units of the water supply system. As a mere example, the aircraft data network may be equipped and/or connected with sensors indicating whether a washroom is occupied or available, whether a faucet is in use, whether a flushing system of a lavatory is in use, whether galley components are in use (particularly galley components requiring water), and/or indicating a water level of a buffer tank of such a water consumer unit.

In a further variant, the aircraft can further comprise a flight attendant interface or input/output panel. Such interface/panel may allow entering certain information or set specific parameters by a flight attendant and/or a pilot. This allows setting a sleeping phase, or identifying the same when a cabin light is dimmed. The controller can then assume that the usage frequency of the monuments, particularly the lavatories, will decrease as the passengers remain in their seats. During such sleeping phase the controller may open the cross feed valve and operate one of the plurality of conveying devices, to convey water to each of the water networks. This operating mode allows saving energy by operating only one conveying device.

In yet a further variant, the cross feed valve can be opened/closed manually, i.e. based on a user command and/or irrespective of any sensor controlled control of the valve. For example, a corresponding input may be made at the flight attendant panel.

The present disclosure is not restricted to the aspects and variants in the described form and order. Specifically, the description of aspects and variants is not to be understood as a specific limiting grouping of features. It is to be understood that the present disclosure also covers combinations of the aspects and variants. Thus, each variant or optional feature can be combined with any other aspect, variant, optional feature or even combinations thereof, insofar as they fall within the scope of the appended claims.

In the following, the present disclosure will further be described with reference to exemplary implementations illustrated in the figures, in which:.

It will be apparent to one skilled in the art that the present disclosure may be practiced in other implementations that depart from these specific details.

<FIG> schematically illustrates a water supply system <NUM>, such as a system <NUM> can distribute (potable) water through an aircraft <NUM>. The aircraft <NUM> is schematically illustrated as an outer skin of the aircraft (A/C skin = aircraft skin), wherein the aircraft further comprises a cabin floor and a cabin ceiling. This is not necessary for the present disclosure, but facilitates explanation of the arrangement of particular components of the water supply system and its water consumer units.

Specifically, in a lower region of the aircraft <NUM>, such as a cargo or storage area underneath the cabin floor, the system comprises a main tank <NUM> configured to store a main supply of potable water. It is to be understood that more than one main tank <NUM> can be employed, but the drawings illustrate only one tank <NUM>. The main tank <NUM> may be filled with potable water via a potable water service panel <NUM> arranged at or in the aircraft skin. This conventional service panel <NUM> is only briefly described. For instance, water can be filled into tank <NUM> via a fill/drain interface or nipple <NUM>. The corresponding pipe or duct may be equipped with a fill/drain valve <NUM>, in order to separate or connect the system <NUM> from the interfaces of the service panel <NUM>. An overflow <NUM> allows filling the tank <NUM> with a maximum level of water. The service panel <NUM> may further be equipped with a door lock and/or handle <NUM> allowing opening and closing a service panel door, and a data interface <NUM> providing a connection port for a data exchange with the system <NUM>.

In use, the water from the main tank <NUM> is guided through a main water pipe <NUM> connected to a water outlet of the main tank <NUM>. If necessary, a water treatment module may be installed, such as a filter or the like, as well as a flow metre in order to determine or sense the amount of water removed from the main tank <NUM>.

A furcation <NUM> divides the main water pipe <NUM> in a plurality of pipe branches. While <FIG> illustrates two branches downstream of the furcation <NUM>, the present disclosure is not restricted to this number of pipe branches. Downstream of the furcation <NUM>, each pipe branch forms one of a plurality of water networks <NUM>, <NUM>. Each water network <NUM>, <NUM> is configured to conduct water from the one of the plurality of pipe branches to at least one of a plurality of water consumer units 11a-11c, 12a-12d. It is to be understood that each water network <NUM>, <NUM> can have any desired topology. For example, one or more water network topologies can be employed, such as a stub-branch network (as illustrated), a circulation or ring pipe, individual supply lines or combinations thereof.

The water consumer units 11a-11c, 12a-12d can be arranged above the cabin floor, which facilitates draining of the water networks <NUM>, <NUM> as well as the water consumer units 11a-11c, 12a-12d by gravity. For instance, the drain valve <NUM> may be opened, so that water runs driven by gravity through the pipes of the water networks <NUM>, <NUM>, through the furcation <NUM>, the main water pipe <NUM> and the drain interface <NUM>. Draining the water from the water supply system may be facilitated pneumatically, i.e. by blowing air through the pipes of the water supply system.

The system <NUM> further comprises in each of the plurality of water networks <NUM>, <NUM> a conveying device <NUM>, <NUM>. Specifically, a first conveying device <NUM> is provided in a pipe branch downstream of furcation <NUM> and is configured to conduct water to each water consumer unit 11a-11c of a first group <NUM> of water consumer units 11a-11c via water network <NUM>. A second conveying device <NUM> is provided in another pipe branch downstream of furcation <NUM> and is configured to conduct water to each water consumer unit 12a-12d of a second group <NUM> of water consumer units 12a-12d. Thus, each water network <NUM>, <NUM> can be operated individually by providing pressurised water from the respective conveying device <NUM>, <NUM>, which receive water from the main tank <NUM> via main water pipe <NUM> and furcation <NUM>.

Each of the first and second group <NUM>, <NUM> can comprise any arbitrary number and any arbitrary type of water consumer units 11a-11c, 12a-12d. As a mere example, each of the groups <NUM>, <NUM> comprises a plurality of lavatories 11a, 11b, 12a, 12b, 12c and one galley 11c, 12d. It is to be understood that a group <NUM>, <NUM> of water consumer units 11a-11c, 12a-12d may also comprise only one water consumer unit 11a-11c, 12a-12d, may comprise only lavatories 11a, 11b, 12a-12c or may comprise only galleys 11c, 12d.

While <FIG> illustrates the first water consumer units group <NUM> in a front portion of the aircraft <NUM> and a second water consumer units group <NUM> in a back portion of the aircraft <NUM>, the grouping of the water consumer units <NUM>, <NUM> can be arbitrarily chosen. As a mere example, the water consumer units groups <NUM>, <NUM> may likewise be arranged on the left-hand side of the aircraft <NUM> and a right-hand side of the aircraft <NUM>, respectively. It is to be understood that also a combination of front/back and right/left grouping of water consumer units <NUM>, <NUM> can be employed. In any case, one group <NUM>, <NUM> of water consumer units 11a-11c, 12a-12d is associated with one water network <NUM>, <NUM>, which conducts water to the respective units 11a-11c, 12a-12d from the tank <NUM> by the respective conveying device <NUM>, <NUM>.

The water supply system further comprises a cross feed valve <NUM> configured to fluidically connect or separate the plurality of water networks <NUM>, <NUM> downstream of the conveying devices <NUM>, <NUM> in the plurality of water networks <NUM>, <NUM>. In other words, the cross feed valve <NUM> allows fluidically connecting or separating the pressurised portion of the respective water networks <NUM>, <NUM>. It is to be understood that the aircraft <NUM> can comprise more than the illustrated two water networks <NUM>, <NUM>. In this case, more than one cross feed valve <NUM> can be employed. For instance, a pair of water networks <NUM>, <NUM> can be fluidically connected to one another by one cross feed valve <NUM>, so that the number of cross feed valves <NUM> could be N-<NUM>, where N is the number of water networks <NUM>, <NUM>. Alternatively, a plurality of cross feed valves <NUM> is installed, so that one or more water networks <NUM>, <NUM> is fluidically connected with at least one other water network <NUM>, <NUM> and/or so that one cross feed valve <NUM> fluidically connects more than two water networks <NUM>, <NUM>.

Referring back to <FIG>, the pipes of the first and second water network <NUM>, <NUM> are arranged in such a manner, that a portion thereof at the cross feed valve <NUM> runs in an at least partially vertical direction. This allows draining the pipes of the first and second water network <NUM>, <NUM> even at the cross feed valve <NUM>, so that no dead water remains after draining.

A controller <NUM> may be provided that can control the plurality of conveying devices <NUM>, <NUM> and the cross feed valve <NUM>. The controller <NUM> can be coupled or connected to further controllers and/or sensors. For instance, each water consumer unit 11a-11c, 12a-12d may have a module controller configured for operating the water consumer of each unit 11a-11c, 12a-12d. Such module controller may indicate to controller <NUM> that water is required (e.g., when a faucet is used, a toilet is flushed or the like). The module controller and/or a sensor <NUM> may provide information to the controller <NUM> about a fill level in a buffer tank in at least one water consumer unit 11a-11c, 12a-12d. Finally, the water networks <NUM>, <NUM> may further be equipped with a respective sensor, such as pressure sensors <NUM>, <NUM>.

The module controller(s) and/or sensor(s) <NUM>, <NUM>, <NUM> can be configured to determine a water supply requirement of at least one of the plurality of water consumer units 11a-11c, 12a-12d. They can further transmit a signal indicating the water supply requirement to the controller <NUM>. It is to be understood that the module controller(s) and/or sensor(s) <NUM>, <NUM>, <NUM> can also transmit a signal to the controller <NUM>, which indicates a current status of the water consumer equipment, the buffer tank, a pressure in the water network <NUM>, <NUM> or the like, while the controller <NUM> determines the water supply requirement of the water consumer units 11a-11c, 12a-12d.

<FIG> additionally illustrates an aircraft data network <NUM>, which may be connected to the module controllers of the water consumer units 11a-11c, 12a-12d. This configuration allows communication between the aircraft data network <NUM> and the controller <NUM>, so that the controller <NUM> can determine the water supply requirement directly based on information derivable from the data network <NUM>.

Based on the water supply requirement, the controller <NUM> may control the conveying devices <NUM>, <NUM> and/or the cross feed valve <NUM>, in order to provide a sufficient amount of water to each of the water consumer units 11a-11c, 12a-12d.

For instance, the controller <NUM> may operate in different control modes depending on the current situation in the water supply system <NUM> of the aircraft <NUM>. Some examples will be explained, such as closing the cross feed valve <NUM> and operating each of the plurality of conveying devices <NUM>, <NUM> in a normal mode. The normal mode refers to the operation of each conveying device <NUM>, <NUM> in such a manner that it conveys an amount of water currently required by the respective water network <NUM>, <NUM>. In other words, this control mode reflects the general use of the water supply system <NUM>.

In another control mode, the cross feed valve <NUM> can be opened, while only one of the plurality of conveying devices <NUM>, <NUM> is operated. Due to the fluidically connected water networks <NUM>, <NUM> via cross feed valve <NUM>, the one conveying device <NUM> (or <NUM>) conveys water to each of the water networks <NUM>, <NUM>. This control mode may be employed, if the overall water requirement is less than in the normal mode, so that energy can be saved by operating only one conveying device <NUM> (or <NUM>). This control mode may also be employed, in case of failure of another conveying device <NUM> (or <NUM>).

In a further control mode, the cross feed valve <NUM> can be opened, while all conveying devices <NUM>, <NUM> operate at a maximum conveying power. Alternatively, all or at least more than one conveying device <NUM>, <NUM> operates at a high power level in this control mode. This control mode allows an increased water supply for one or more of the plurality of water consumer units 11a-11c, 12a-12d, such as filling one or more buffer tanks before a flight of the aircraft <NUM>. Likewise, in case a plurality of lavatories are flushed at the same time, an increased water supply requirement may occur, so that this control mode may be employed.

In another control mode, the cross feed valve <NUM> can be opened, while only one conveying device <NUM>, <NUM> is operated. This allows a cross-check of sensors in the water networks <NUM>, <NUM>.

Yet another control mode may be employed in case of a leakage in one of the water networks <NUM>, <NUM>. In this case, the cross feed valve <NUM> can be closed and the conveying device <NUM>, <NUM> of the water network <NUM>, <NUM> having the leakage is stopped. Thus, the water network <NUM>, <NUM> having the leakage can be isolated from the water supply system <NUM>.

In any case, the cross feed valve <NUM> allows achieving redundancies in the water supply system <NUM> and additionally further advantageous control modes.

In addition, for the case that one of the conveying devices <NUM>, <NUM> does not operate, the conveying devices <NUM>, <NUM> are each configured to act as a check valve, in order to avoid a hydraulic circle. Alternatively or additionally, a check or shut-off valve (not illustrated) can be employed between the cross feed valve <NUM> and the respective conveying device <NUM>, <NUM>.

<FIG> schematically illustrates a portion of the water supply system <NUM> comprising a cross feed valve <NUM>, particularly the portion comprising the furcation <NUM> and parts of the water networks <NUM>, <NUM> downstream of cross feed valve <NUM>. The cross feed valve <NUM> can be implemented as a shutoff valve, particularly a single shutoff valve <NUM>. The cross feed valve <NUM> is connected to a portion of the pipes of the water networks <NUM>, <NUM> that run substantially vertically, i.e. that has an arrangement including a vertical component. This allows draining the pipes by gravity. In addition, there is no dead end between the cross feed valve <NUM> and a pipe of one of the water networks <NUM>, <NUM>. Thus, no water is kept in a dead end pipe portion between a pipe of the water networks <NUM>, <NUM> and the cross feed valve <NUM>. This increases the hygienic situation of the water supply system <NUM>.

<FIG> schematically illustrates a detail of a cross feed valve <NUM>, such as the valve <NUM> of <FIG>. Particularly, one shutoff valve <NUM> having a first port <NUM> and a second port <NUM> can be employed. The first port <NUM> is fluidically connected to a pipe of a first water network <NUM> of the plurality of water networks <NUM>, <NUM>, and the second port <NUM> is fluidically connected to a pipe of a second water network <NUM> of the plurality of water networks <NUM>, <NUM>. This allows conducting water through each of the water networks <NUM>, <NUM>, while providing an easy to implement possibility for fluidically interconnecting both water networks <NUM>, <NUM>.

As a mere example, each port <NUM>, <NUM> is directly attached to an opening in the pipe of the respective water network <NUM>, <NUM>. Such direct attachment may be achieved by welding, adhering or a very short fitting.

The arrangement of <FIG> particularly facilitates unhindered flow of water in the water networks <NUM>, <NUM>. Specifically, if the cross feed valve <NUM> is closed, the pipes of the respective water networks <NUM>, <NUM> can function as usual pipes without significant influence on the water flow in the pipe.

<FIG> schematically illustrates an aircraft <NUM> comprising a water supply system <NUM>. For instance, a water supply system <NUM> as illustrated and described with respect to <FIG> can be installed in the aircraft <NUM>. It is to be understood that a plurality of such water supply systems <NUM> can be installed.

Claim 1:
A water supply system (<NUM>) for a plurality of water consumer units (<NUM>, <NUM>) in an aircraft (<NUM>), the system comprising:
a main tank (<NUM>) configured to store a main supply of water;
a main water pipe (<NUM>) connected to an outlet of the main tank (<NUM>); and
a plurality of water networks (<NUM>, <NUM>), each configured to conduct water from the main tank (<NUM>) to at least one of the plurality of water consumer units (<NUM>, <NUM>),
wherein the plurality of water consumer units (<NUM>, <NUM>) is partitioned in a first group (<NUM>) of water consumer units (11a, 11b, 11c) and at least a second group (<NUM>) of water consumer units (12a, 12b, 12c, 12d),
characterized in that
each of the plurality of water networks (<NUM>, <NUM>) comprises a conveying device (<NUM>, <NUM>) configured to convey water to each water consumer unit (11a, 11b, 11c, 12a, 12b, 12c, 12d) of one of the groups (<NUM>, <NUM>), and
the water supply system (<NUM>) further comprises:
a cross feed valve (<NUM>) configured to fluidically connect or separate the plurality of water networks (<NUM>, <NUM>) downstream of the conveying devices (<NUM>, <NUM>) in the plurality of water networks (<NUM>, <NUM>).