Sanitary unit having a greywater recovery system for flushing water

Abstract

The invention relates to a method for flushing a sanitary unit, comprising the steps of: - supplying greywater from a greywater line (61) into an interior of a greywater container (40); - temporarily storing the greywater in the greywater container (40) under ambient pressure; - conveying the greywater by means of a greywater pump (30) from the interior of the greywater container (40) under ambient pressure to a flushing device (11), the greywater being conveyed through a filter arrangement (50) arranged in the interior of the greywater container (40) to the greywater pump (30) located behind this filter device (50) in the flow direction; - discharging the greywater using overpressure from one or more flushing openings of the flushing device (11) into a sanitary element (10) to be flushed. The invention likewise relates to a sanitary unit having the features necessary for carrying out the method.

Description

[0001] Eisenführ Speiser

[0002] Hamburg, September 12, 2025

[0003] Our reference: TH 815-02WO LBI / akp

[0004] Applicant / Owner: Trainvac GmbH

[0005] Official file number: New registration

[0006] Trainvac GmbH

[0007] Elbring 10e, 22880 Wedel,

[0008] Sanitary unit with greywater recovery for water flushing

[0009] The invention relates to a method for flushing a sanitary unit using greywater. A further aspect of the invention is a sanitary unit with a flushing device for flushing a sanitary element using greywater. The method and the sanitary unit according to the invention are particularly designed and configured for use in mobile applications in vehicles, i.e., in applications where running water is typically not available for flushing a sanitary unit and where the wastewater from a sanitary unit cannot be directly discharged into a terrestrial sewer system, but rather fresh and wastewater must be temporarily carried in corresponding tanks on board the vehicle.

[0010] In plumbing, a basic distinction is made between fresh water, grey water, and black water. Fresh water is clean water that is carried along and may also be suitable for drinking. Grey water is wastewater from a hand basin or shower, which is contaminated by small particles and soap residue. Black water is water from toilets.

[0011] Typically, vehicles equipped with a sanitary unit carry fresh water in a fresh water tank. This water supplies the water to the faucet of a sink or shower and to the flushing mechanism of a toilet bowl. The fresh water supply can be gravity-fed, meaning the tank is positioned at a higher elevation and drains by gravity, ensuring a robust and reliable supply. Grey water and black water are collected in a wastewater holding tank. In this way, the entire sanitary unit can be configured with just two separate water tanks. The fresh water tank empties continuously during operation, while the wastewater holding tank fills up.The fresh water tank must therefore be filled and the wastewater tank emptied at regular intervals. For this purpose, suitable service stations are provided at train stations, bus stations, airports, or marinas, where the wastewater tank can be emptied and fresh water can be added to the fresh water tank. To ensure long intervals between these filling and emptying processes, appropriately sized fresh water tanks and wastewater tanks must be provided on board the vehicle.

[0012] A further developed sanitary unit is known from EP 2531658 B1. In this sanitary unit, greywater from a washbasin is temporarily stored in a flushing water tank and used to flush a toilet. For this purpose, the flushing water tank is pressurized with compressed air, and the resulting overpressure forces the stored greywater to the toilet's flushing nozzles. A filter is installed in the inlet pipe from the washbasin outlet to the flushing water tank for pre-cleaning the greywater. This filter removes particles and soap residue from the greywater, thus preventing an accumulation of these solids and soap residue in the flushing water tank.This system advantageously saves fresh water and allows for a correspondingly smaller fresh water tank, as the fresh water is essentially used twice: once for handwashing in the sink and again for flushing the toilet. However, a disadvantage is the complex system technology, which requires filtering the grey water, cleaning and replacing the filter at regular intervals, and controlling the flow of grey water from the flushing tank to the toilet's flushing nozzles by generating overpressure in the flushing tank.

[0013] A similar sanitary installation is known from EP 2937480 B1. Here, too, greywater is temporarily stored in a flushing water tank and forced out of this tank by means of a compressed air supply and the creation of overpressure within the tank, and fed to the flushing nozzles of a toilet. The sanitary unit also has a filter for filtering the greywater; in this known embodiment, this filter is located inside the flushing water tank. A disadvantage of this known sanitary unit is also the complex system technology, which necessitates forcing the greywater out of the flushing water tank. Furthermore, the filter's location within the flushing water tank makes it difficult to access for maintenance and replacement.

[0014] A water supply system with a greywater treatment device is known from DE 10 2016 217 986 A1. In this sanitary system, the greywater treatment tank is cleaned using fresh water, and for this purpose, the entire interior is rinsed with fresh water. This method has the disadvantage that it requires complex additional piping, sufficient fresh water pressure is difficult to achieve for reliable cleaning, and significant quantities of fresh water must be consumed for cleaning, which considerably reduces the desired fresh water savings.

[0015] While existing devices with greywater intermediate storage for toilet flushing ensure that the freshwater tank lasts for a longer period of use, thus extending the intervals between refills, this advantage comes at the cost of increased complexity for the unit and its maintenance. This complexity stems from the handling of greywater, including the necessary filtration, cleaning, and filter replacement, as well as the design of the flushing tank to force the water into the toilet's flushing nozzles. A sanitary unit is needed that avoids at least one or more of these drawbacks, thereby improving freshwater supply intervals, maintenance intervals, and reducing the unit's susceptibility to malfunctions.

[0016] This problem is solved according to the invention by a method for flushing a sanitary unit, comprising the steps of: supplying greywater from a greywater pipe into the interior of a greywater tank, temporarily storing the greywater in the greywater tank under ambient pressure, pumping the greywater from the interior of the greywater tank under ambient pressure to a flushing device by means of a greywater pump, wherein the greywater is pumped through a filter arrangement located in the interior of the greywater tank to the greywater pump located downstream of this filter arrangement in the direction of flow, and discharging the greywater with overpressure from one or more flushing openings of the flushing device into a sanitary element to be flushed.

[0017] The method according to the invention simplifies the use of greywater for flushing a sanitary fixture within a sanitary unit. The greywater is temporarily stored in a greywater tank at ambient pressure. It can originate, for example, from a sink or a shower drain. Often, it is possible to feed the greywater from the sink to the greywater tank by gravity. When needed, the greywater is then pumped from the greywater tank to a flushing device by means of a greywater pump. The interior of the greywater tank is at ambient pressure. During this pumping process, the greywater is passed through a filter device located inside the greywater tank. This creates a pressure differential that is advantageous for efficient filtration and flow through the filter device, thus benefiting the greywater purification process.The greywater is then discharged in the direction of flow behind the greywater pump with overpressure from one or more flushing openings of the flushing device into the sanitary element to be flushed, for example the bowl of a toilet.

[0018] The method according to the invention therefore achieves several advantages over the prior art. Firstly, the greywater tank is never under the kind of overpressure required for squeezing the greywater out of the tank in the prior art, but rather is under ambient pressure. The design of the greywater tank, both with regard to its wall thickness and its geometric contour, can therefore be constructed with a high degree of freedom; in particular, advantageous, space-saving external contours of the greywater tank can be realized for installation in a sanitary unit.The greywater is pumped through the filter assembly using two methods: firstly, a beneficial pressure differential generated by the greywater pump, and secondly, the filter assembly's placement within the greywater tank, combined with the constant pressure across the filter assembly during extended periods of operation, allows for efficient self-cleaning. This self-cleaning is often achieved simply through vibrations occurring on board the vehicle during operation. As a result, filter cake particles falling from the filter assembly accumulate in the greywater tank, and this continuous self-cleaning process prevents any reduction in the filter assembly's flow rate.

[0019] According to a first preferred embodiment, the greywater tank has a solids discharge opening at its lower section (in the direction of gravity), and an actuator-operated solids shut-off valve is controlled to allow flow through the discharge opening and to remove solids from the lower section of the greywater tank. This method, as developed in this way, efficiently allows solids that accumulate in the lower section of the greywater tank as a result of the cleaning action of the filter assembly to be discharged through a solids discharge opening. For this purpose, a solids shut-off valve can be actuated by an actuator and opened for a period of time to discharge the solids from the greywater tank.This actuator-operated opening of the solids shut-off valve can, for example, be controlled electronically and pneumatically actuated. It can occur at regular intervals; alternatively or additionally, the control can also be based on the number of completed flushing cycles from the greywater tank or triggered by a sensor that detects the amount of deposited solids.

[0020] It is particularly preferred if vibrations from the operation of a vehicle in which the process is carried out are introduced into the filter assembly, and if solids adhering to the filter assembly in a filter cake are detached from the filter arrangement by means of these introduced vibrations and carried by gravity into the lower section. This process step takes advantage of the arrangement of the filter assembly in the unpressurized greywater tank and introduces vibrations, such as those originating from a drive system or accelerations from the vehicle chassis or body in which the sanitary unit is installed, into the greywater tank in order to trigger an advantageous self-cleaning effect.

[0021] It is even more preferred if the wastewater from the sanitary unit is conveyed to a wastewater collection tank via a wastewater pipe, and the solids from the solids discharge opening are introduced into the wastewater pipe via a solids discharge pipe and conveyed to the wastewater collection tank. According to this embodiment, the solids are introduced into the wastewater pipe that also carries the wastewater from the sanitary unit, which is flushed from the greywater tank, and are collected together with this wastewater in the wastewater collection tank. Separate storage of the solids is therefore unnecessary.

[0022] It is even more preferred if the wastewater from the sanitary fixture is drawn into an intermediate tank via an intermediate wastewater line by creating a vacuum in this intermediate tank while the intermediate wastewater line is blocked by means of an intermediate wastewater valve and the intermediate wastewater valve is opened to rapidly create a vacuum in a section of the intermediate wastewater line located between the intermediate wastewater valve and the sanitary fixture, and the wastewater is thereby drawn into the intermediate tank, further characterized in that the interiors of the intermediate tank and the greywater tank are arranged adjacent to each other in such a way that they are separated from each other at least in one area by a partition wall which deforms under the build-up and release of the vacuum in the intermediate tank and thereby causes pressure changes in the interior of the greywater tank.which cause the solids adhering as a filter cake to detach from the filter arrangement.

[0023] According to this embodiment, the inventive method is further implemented such that the wastewater is removed from the sanitary element by first being drawn into an intermediate tank via an intermediate wastewater line and then conveyed from this intermediate tank via a wastewater line into the wastewater collection tank. The drawing into the intermediate tank is effected by a vacuum within the intermediate tank. This vacuum can typically be created by first establishing a vacuum in the intermediate tank with the valves closed, by connecting the interior to a suitable vacuum source. After the vacuum has been established, the wastewater is then drawn into the intermediate tank by opening a valve and thus by means of a rapid vacuum effect. The intermediate tank and the greywater tank are arranged adjacent to each other in such a way that their interiors are separated from each other by a partition.which can deform due to this build-up and release of the vacuum. This deformation advantageously generates pressure pulses in the greywater tank, which act on the filter assembly and detach filter cake from it. These solid particles of the filter cake then fall into the lower section of the greywater tank and collect there. This achieves an advantageous passive cleaning of the filter assembly. In an alternative or additional embodiment of the method, it is provided that the wastewater from the sanitary element is routed via an intermediate wastewater line into a buffer tank and from this buffer tank is discharged via the wastewater line into the wastewater collection tank by building up overpressure in this buffer tank.While the wastewater line is blocked by means of a wastewater valve, and the wastewater valve is opened after the build-up of overpressure in the intermediate tank for a rapid reduction of the overpressure in the intermediate tank and a rapid expulsion of the wastewater from the intermediate tank via the wastewater line into the wastewater collection tank, further characterized in that the interiors of the intermediate tank and the greywater tank are arranged adjacent to each other in such a way that they are separated from each other at least in one area by a partition wall which deforms under the build-up and reduction of the overpressure in the intermediate tank and thereby causes pressure changes in the interior of the greywater tank, which cause the detachment of solids adhering as a filter cake from the filter arrangement.

[0024] In this embodiment, the wastewater in the intermediate tank is transported from the intermediate tank to the wastewater collection tank by means of overpressure. Again, the intermediate tank is pressurized for this purpose, which can be achieved in various ways, for example, by slowly building up overpressure with closed valves and then rapidly releasing the pressure and discharge the wastewater from the intermediate tank to the wastewater collection tank by opening a valve. In this embodiment as well, the intermediate tank and the greywater tank are adjacent and separated from each other by a deformable partition wall. This partition wall deforms as the overpressure in the intermediate tank builds up and releases, thereby creating a pressure pulse effect on the filter assembly to dislodge filter cake.

[0025] In both embodiments, it is generally understood that the partition can be designed as a common wall of the intermediate tank and the greywater tank, for example, by molding one of the two tanks onto the other or by manufacturing the two tanks in an integrated process. Alternatively, the partition can be realized by attaching two separate tanks with matching outer surfaces to each other, for example, by gluing, screwing, and / or positively locking them together, or simply by arranging them flush against each other, so that the partition is formed by the two matching and contacting outer wall areas.According to a further preferred embodiment, the solids discharge line opens into the wastewater line in such a way that a fluid flow directed into the wastewater collection tank causes a suction effect on the solids discharge line, and a solids shut-off valve closing the solids discharge opening is opened in temporal relation to the opening of the wastewater shut-off valve after the overpressure has built up, in order to draw solids out of the greywater tank by means of the wastewater flowing through the wastewater line.

[0026] In principle, the removal of deposited solids from the greywater tank can naturally occur by gravity, as these are already located in the lower section of the greywater tank and the solids discharge opening is situated in this lower area. To increase the removal rate, a wastewater flowing through the sewer line can also exert suction on the solids discharge line. For this purpose, the line is designed with a suitable geometric shape, for example, by means of a Y-shaped inlet or an inlet into a flow-constriction with a Venturi effect, thereby achieving the suction effect.The opening of the wastewater shut-off valve and the solids shut-off valve must be carried out in temporal relation to each other, which means that the opening of one valve triggers the opening of the other valve, or both valves are opened by a common trigger or two time-delayed triggers, and consequently the two valves are opened in quick succession, either with a time delay or synchronously, in order to achieve the desired suction effect.

[0027] It is even more preferred if the greywater tank and the intermediate tank are integrally designed, in that the greywater tank and the intermediate tank have an outer tank wall enclosing the interior spaces of both tanks, and the partition wall is arranged in a space enclosed by this outer tank wall.

[0028] As previously explained, greywater tanks and intermediate tanks can generally be designed as separate containers and then joined together by bonding, screwing, or interlocking clips, interlocking joints (e.g., dovetail joints), or similar means. Preferably, the two containers are integrally formed, meaning a single component manufactured in a continuous production process, for example, by producing both containers in a single blow molding operation, optionally in two stages. The two containers are then enclosed by an outer wall that encloses both interior spaces, and the partition is positioned accordingly within this enclosed space.

[0029] It is even more preferred to determine whether the amount of water stored in the interior of the greywater tank is sufficient to carry out a flushing process of the sanitary unit by means of the flushing device, and to supply fresh water to the greywater tank if it is determined that the amount of water is insufficient for such a flushing process, wherein the flushing water is supplied through the filter device into the interior of the flushing water tank and flows through the filter device in a flow direction that is opposite to the flow direction of the greywater from the interior to the flushing device, wherein preferably the fresh water is supplied to the greywater tank at least sectionally by gravity with a drop height of at least 3 times the diameter of the fresh water pipe.

[0030] According to this embodiment, the supply of fresh water to the greywater tank ensures that sufficient liquid is present in the greywater tank in every operating condition to perform a flushing cycle of the sanitary fixture. In this way, even if, for example, no greywater could be collected in the greywater tank for an extended period, but flushing cycles were performed, it is possible to continue flushing cycles even in the absence of further greywater being supplied. It is particularly preferred if the fresh water is supplied to the greywater tank via a drop of at least three times the diameter of the freshwater pipe.Such an arrangement reliably prevents back-contamination from the greywater tank into the freshwater source, as the gravitational flow of the freshwater reliably prevents such migration of germs.

[0031] Finally, in the method according to the invention, it is even more preferred if a filter cleaning line branches off between the grey water pump and the rinsing device, which is connected to a filter cleaning nozzle, and that the flow through the filter cleaning line is blocked and released by means of a filter cleaning valve, wherein preferably the grey water is discharged into the filter device in such a way that it flows through the filter device against the flow direction of the grey water from the interior of the grey water tank to the grey water pump.According to this embodiment, additional cleaning of the filter from trapped solids is achieved by a filter cleaning nozzle. This nozzle directs a pressurized flow of greywater, derived from the greywater pump, onto the filter assembly. This cleaning flow exits the filter cleaning nozzle in the opposite direction to the flow direction through the filter assembly when greywater is pumped from the greywater tank to the flushing device of the sanitary fixture. Such an arrangement can be particularly effective, for example, when a cylindrical filter element is used as the filter assembly. The flow is radial from the outside to the inside through this element, and the greywater is drawn from the interior of the filter element to be fed to the flushing device.In this case, the filter cleaning nozzle can be located inside the filter element and direct one or more pressurized fluid jets in a radial, outward direction with respect to the central longitudinal axis of the filter element onto the inner circumferential surface of the filter element.

[0032] Another aspect of the invention is a sanitary unit for use in vehicles, comprising: a greywater tank with an interior for the temporary storage of greywater, which can be supplied to the interior via a greywater filling opening formed in a greywater tank wall enclosing the interior; a flushing device for flushing a sanitary element; a greywater flushing line connecting the greywater tank to the flushing device of the sanitary element for supplying greywater from the greywater tank to the flushing device; a filter arrangement arranged in the interior of the greywater tank, which is connected to the interior of the greywater tank on the flow inlet side and to the greywater flushing line on the flow outlet side for pumping the greywater from the interior of the greywater tank through the filter arrangement into the greywater flushing line; and a greywater pump.The sanitary unit according to the invention comprises a greywater tank, a flushing device for flushing a sanitary fixture, and a greywater flushing line that conveys greywater from the greywater tank to the flushing device by means of a greywater pump drawing greywater from the interior of the greywater tank and supplying it to the flushing device under pressure. The greywater pump is designed and arranged, and in particular configured, to draw greywater from the greywater tank when the interior of the greywater tank is at ambient pressure. The sanitary unit is advantageous in that the greywater tank can be designed with a variable geometry.because it does not have to withstand overpressure to squeeze out the rinse water. Furthermore, the filter arrangement inside the grey water tank allows for a beneficial self-cleaning effect when the sanitary unit is used in vehicles, through vibrations that act on the sanitary unit during vehicle operation, so that the filter arrangement is regularly freed from adhering solids during operation.

[0033] With regard to specific advantages, effects, and variations of the aspects of this sanitary unit according to the invention, reference is made to the preceding explanation of the method according to the invention. The advantages, alternatives, and effects explained therein also apply to the corresponding device features of the sanitary unit.

[0034] It is preferred to further develop the sanitary unit by a solids discharge opening on a section of the greywater tank located at the bottom in the direction of gravity, an actuator-operated solids shut-off valve for blocking and releasing the flow from the solids discharge opening, and a control device designed to actuate the solids shut-off valve to release a flow through the solids discharge opening and to discharge solids from the lower section of the greywater tank through the solids discharge opening from the greywater tank.

[0035] Furthermore, it is preferred to extend the sanitary unit by connecting the sanitary element to a wastewater collection tank via a wastewater pipe for the removal of wastewater and by connecting the solids removal opening to the wastewater pipe via a solids removal pipe for the introduction of solids into the wastewater pipe and conveying the solids through the wastewater pipe to the wastewater collection tank.

[0036] It is even more preferred to further develop the sanitary unit by means of an intermediate tank connected to the sanitary element via a wastewater intermediate line for drawing wastewater from the sanitary element into the intermediate tank, a vacuum source connected to the intermediate tank via a vacuum line for creating a vacuum in the intermediate tank, a wastewater intermediate valve arranged between the sanitary element and the intermediate tank, and a control device designed to close the wastewater intermediate valve while a vacuum is being created in the intermediate tank and to open the wastewater intermediate valve after a vacuum has been created in the intermediate tank for rapid drawing of wastewater from the sanitary unit into the intermediate tank, wherein it is further provided that the interiors of the intermediate tank and the greywater tank are arranged adjacent to each other in such a way as to...that they are separated from each other at least in one area by a partition wall which deforms under the build-up and release of negative pressure in the intermediate tank, thereby causing pressure changes in the interior of the greywater tank, which cause solids adhering as a filter cake to detach from the filter arrangement.

[0037] It is further preferred to extend the sanitary unit by means of an intermediate tank connected to the sanitary element via a wastewater intermediate line for temporarily storing the wastewater from the sanitary element in the intermediate tank; a pressure source connected to the intermediate tank via a pressure line for building up pressure in the intermediate tank; a wastewater valve arranged between the intermediate tank and the wastewater collection tank for blocking and releasing the wastewater flow through the wastewater line; a control device configured to block the wastewater valve while pressure is being generated in the intermediate tank and to open the wastewater valve after pressure has been built up in the intermediate tank for a rapid discharge of the wastewater from the intermediate tank into the wastewater collection tank; furthermore, it is provided thatthat the intermediate tank and the greywater tank are arranged in such a way that they are separated from each other, at least in one area, by a partition wall which deforms under the build-up and release of overpressure in the intermediate tank and thereby causes pressure changes in the interior of the greywater tank, which cause solids adhering as a filter cake to detach from the filter arrangement.

[0038] The sanitary unit can be further developed by arranging the solids discharge line into the wastewater line in such a way that a fluid flow directed into the wastewater collection tank creates a suction effect on the solids discharge line, and by designing the control device to open a solids shut-off valve, which closes the solids discharge opening, in temporal relation to the opening of the wastewater shut-off valve after the build-up of overpressure, in order to draw solids from the greywater tank by means of the wastewater flowing through the wastewater line. The sanitary unit can be further developed by integrating the greywater tank and the intermediate tank, by having an outer wall enclosing the interior spaces of both tanks, and by arranging the partition wall in a space enclosed by this outer wall.

[0039] The sanitary unit according to the invention can be further developed by a water quantity sensor, which is designed and arranged to determine the quantity of water in the interior of the greywater tank and is further characterized in that the control device is connected to the level sensor via a signal and is designed to determine whether the determined quantity of water is sufficient to carry out a flushing process of the sanitary unit by means of the flushing device and to control a fresh water shut-off valve to supply fresh water to the greywater tank if it is determined that the quantity of water is not sufficient for such a flushing process, wherein the fresh water is supplied via a fresh water line opening into the filter device, is guided through the filter device into the interior of the flushing water tank and flows through the filter device in a flow direction.which is opposite to the flow direction of the greywater from the interior to the flushing device, wherein preferably the fresh water pipe supplies the fresh water to the greywater tank at least sectionally by gravity with a drop height of at least 3 times the diameter of the fresh water pipe.

[0040] Finally, the sanitary unit can be further developed by branching off a filter cleaning line from the flushing line downstream of the greywater pump and feeding it to a filter cleaning nozzle, and by providing a filter cleaning valve which can block or release the flow through the filter cleaning line, and preferably by arranging the filter cleaning nozzle to discharge the greywater into the filter device in such a way that it flows through the filter device against the flow direction of the greywater from the interior of the greywater tank to the greywater pump.

[0041] With regard to the effects, advantages, and benefits of these advantageous embodiments of the sanitary unit according to the invention, reference is made to the preceding explanation of the method according to the invention and its corresponding further developments relating to these device features. Finally, another aspect of the invention is the use of a sanitary unit of the previously described design in such a way that the interior of the greywater tank is under ambient pressure, optionally subjected to pulsed overpressure or underpressure by deformation of the partition wall, and that the greywater is drawn from the interior of the greywater tank by means of the greywater pump and pumped to the flushing device.

[0042] This specific use allows for an advantageous design of the greywater tank, which does not have to withstand overpressure for squeezing out rinse water and can therefore be designed with a geometrically freely designed tank wall and corresponding tank wall thickness.

[0043] A preferred embodiment of the invention is explained with reference to the accompanying figure. The figure shows a schematic representation of the sanitary unit according to the invention.

[0044] The figure shows a sanitary unit with a sanitary element in the form of a toilet bowl 10, which is flushed by means of a flushing device 11. The wastewater from the toilet bowl 10 is conveyed via an intermediate wastewater line 12 with an integrated, pneumatically switchable shut-off valve 12a into a transfer tank as an intermediate container 20 and from this intermediate container via a wastewater line 21 into a wastewater collection tank 90.

[0045] The flushing device 11 is symbolically represented in the figure by a single flushing nozzle, but can typically consist of several flushing nozzles which distribute the flushing water under pressure to clean the toilet bowl. The flushing device is supplied with flushing water from a greywater tank 40 via a greywater pump 30. For this purpose, the greywater pump 30 draws the water stored in the intermediate tank from the interior of a filter assembly 50 with a cylindrical filter wall and pumps it under pressure through a flushing line 13 to the flushing device 11.

[0046] The greywater tank 40 and the intermediate tank 20 are designed as an integral container with a common outer wall 22 and a partition 23 separating the interiors of the greywater tank 40 and the intermediate tank 20. Greywater is supplied to the greywater tank from the drain of a hand basin 60. This greywater flows through a greywater supply line 61 and via a greywater inlet opening into the interior of the greywater tank and, in order to be drawn in by the greywater pump 30, must flow through the filter wall of the filter assembly 50. Here it is cleaned of suspended solids and soap residues and can therefore be used as flushing water for the flushing device 11 of the toilet bowl 10.

[0047] A level sensor 42 is connected to a control unit 100 and sends a signal to this control unit when a predetermined liquid volume in the greywater tank is undershot. An additional level sensor can also be provided to detect a maximum fill level in the greywater tank. When this additional level sensor detects the maximum fill level, greywater can be removed from the greywater tank to prevent overflow, for example, through a solids discharge opening 43 (described in more detail below) or by triggering a flushing cycle of the sanitary fixture. The control unit is also connected to the valves and the greywater pump via a signal connection; this is not indicated by separate connections in the figure.Fresh water flows from a fresh water tank 70 into the interior of the filter assembly 50 via a fresh water valve 71a, which is connected to a fresh water valve 71a. If the volume in the grey water tank falls below a predetermined level, fresh water can be added to the grey water tank by opening the fresh water valve 71a. This fresh water flows through the filter assembly 50 in the opposite direction to the grey water supplied from the hand basin 60, thereby removing filter cake from the outer wall of the filter assembly and cleaning it.

[0048] Downstream of the greywater pump 30, a filter backwash line 41 branches off from the backwash line 13. This filter backwash line 41 can be opened and closed by means of a filter backwash valve 41a and, like the freshwater line 71, leads into the interior of the filter assembly 50. Inside this interior, it is connected to one or more nozzles from which the pressurized greywater is expelled radially onto the inner filter wall of the cylindrical filter assembly, thereby also cleaning the filter assembly by removing filter cake from the outer wall.

[0049] A solids discharge opening 43 is located in the lower section of the greywater tank 40, which leads into a solids discharge line 44. This solids discharge line 44 can be opened and closed by a solids discharge valve 44a. The solids discharge line 44 leads into the wastewater line 21 and therefore allows solids from the bottom of the greywater tank to be discharged into the wastewater collection tank 30 by opening the solids discharge valve 44a. The discharge of the solids from the greywater tank occurs by gravity and is supported by a suction effect exerted on the solids discharge line 44 by wastewater flowing through the wastewater line 21.

[0050] The intermediate tank 20 is connected to a vacuum source 25 via a vacuum valve 24a and a vacuum line 24. This allows a vacuum to be created in the intermediate tank, and this vacuum, when the wastewater intermediate valve 12a is opened, can cause an effective and rapid suction of wastewater from the toilet bowl 10 into the intermediate tank 20.

[0051] The intermediate tank 20 is connected to a compressed air source 80 via a compressed air line 81. This could, for example, be compressed air already present in the vehicle. The intermediate tank can be pressurized via this compressed air line in order to force the wastewater previously drawn into it through the wastewater line 21 into the wastewater collection tank 90.

[0052] These suction and discharge processes from the intermediate tank 20 exert a force on the partition 23, causing it to deform. This deformation generates pulsating overpressure and underpressure waves in the interior of the greywater tank 40, which is generally at ambient pressure. This causes and promotes the detachment of filter cake from the filter assembly 50. This detachment is further facilitated by the fact that, when the sanitary unit according to the invention is installed on board a vehicle, the general vibrations and shocks of the vehicle during operation also cause such detachment of filter cake from the filter assembly 50. The filter assembly thus achieves a high degree of self-cleaning, so that additional cleaning via the filter cleaning line 41 is only necessary in certain operating situations.

Claims

Patent claims 1. Method for flushing a sanitary unit, comprising the steps of: a) supplying greywater from a greywater pipe into the interior of a greywater tank, b) temporarily storing the greywater in the greywater tank under ambient pressure, c) pumping the greywater from the pressurized interior of the greywater tank to a flushing device by means of a greywater pump, wherein the greywater is pumped through a filter arrangement located in the interior of the greywater tank to the greywater pump located downstream of this filter arrangement in the direction of flow, d) discharging the greywater under overpressure from one or more flushing openings of the flushing device into a sanitary element to be flushed.

2. Method according to claim 1, characterized in that the greywater tank has a solids discharge opening at a section of the greywater tank located at the bottom in the direction of gravity, and that an actuator-operated solids shut-off valve is controlled to allow flow through the solids discharge opening and to discharge solids from the lower section of the greywater tank through the solids discharge opening, wherein preferably vibrations from the operation of a vehicle in which the method is carried out are introduced into the filter device and solids of a filter cake adhering to the filter device are detached from the filter arrangement by means of these introduced vibrations and are guided gravitationally into the lower section.

3. Method according to claim 2, characterized in that wastewater from the sanitary element is fed to a wastewater collection tank via a wastewater pipe and the solids from the solids discharge opening are introduced into the wastewater pipe via a solids discharge pipe and fed to the wastewater collection tank via the wastewater pipe.

4. Method according to claim 3, characterized in that the wastewater from the sanitary element is drawn into an intermediate container via a wastewater intermediate line by creating a vacuum in this intermediate container while the wastewater intermediate line is blocked by means of a wastewater intermediate valve and the wastewater intermediate valve is opened to rapidly create a vacuum in a section of the wastewater intermediate line located between the wastewater intermediate valve and the sanitary element, and the wastewater is thereby drawn into the intermediate container, further characterized in that the interior of the intermediate container and the interior of the greywater container are arranged adjacent to each other in such a way that they are separated from each other at least in one area by a partition wall which deforms under the build-up and release of the vacuum in the intermediate container and thereby causes pressure changes in the interior of the greywater container.which cause the solids adhering as a filter cake to detach from the filter arrangement.

5. Method according to claim 3 or 4, characterized in that the wastewater from the sanitary element is routed via an intermediate wastewater line into an intermediate container and discharged from this intermediate container via the wastewater line into the wastewater collection tank by building up overpressure in this intermediate container while the wastewater line is blocked by means of a wastewater valve and the wastewater valve is opened after the overpressure has built up in the intermediate container for a rapid reduction of the overpressure in the intermediate container and forcing the wastewater out of the intermediate container via the intermediate wastewater line into the wastewater collection tank. further preferably characterized in that the interior of the intermediate tank and the interior of the greywater tank are arranged adjacent to each other in such a way that they are separated from each other at least in one area by a partition wall which deforms under the build-up and release of the overpressure in the intermediate tank and thereby causes pressure changes in the interior of the greywater tank which cause solids adhering as a filter cake to detach from the filter arrangement.

6. Method according to claim 5, characterized in that the solids discharge line opens into the wastewater line in such a way that a fluid flow directed into the wastewater collection tank causes a suction effect on the solids discharge line and that a solids shut-off valve closing the solids discharge opening is opened in temporal relation to the opening of the wastewater shut-off valve after the overpressure has built up in order to draw solids out of the greywater tank by means of the wastewater flowing through the wastewater line.

7. Method according to one of the preceding claims, characterized in that the greywater tank and the intermediate tank are integrally formed, in that the greywater tank and the intermediate tank have an outer tank wall enclosing the interior spaces of both tanks and the partition wall is arranged in a space enclosed by this outer tank wall.

8. Method according to one of the preceding claims, characterized in that it is determined whether the quantity of water stored in the interior of the greywater tank is sufficient to carry out a flushing process of the sanitary unit by means of the flushing device, and that fresh water is supplied to the greywater tank if it is determined that the quantity of water is not sufficient for such a flushing process, wherein the flushing water is supplied through the filter device into the interior of the flushing water tank and the filter device is traversed in a flow direction that is opposite to the flow direction of the greywater from the interior to the flushing device. preferably, the fresh water is fed to the grey water tank at least partially by gravity with a drop height of at least 3 times the diameter of the fresh water pipe.

9. Method according to one of the preceding claims, characterized in that a filter cleaning line branches off between the grey water pump and the rinsing device, which is connected to a filter cleaning nozzle, and that the flow through the filter cleaning line is blocked and released by means of a filter cleaning valve, wherein preferably the grey water is discharged into the filter device in such a way that it flows through the filter device in the opposite direction to the flow direction of the grey water from the interior of the grey water tank to the grey water pump.

10. Sanitary unit for use in vehicles, comprising: a grey water tank with an interior for the temporary storage of grey water, which can be supplied to the interior via a grey water filling opening formed in a grey water tank wall enclosing the interior; a flushing device for flushing a sanitary element; a grey water flushing line connecting the grey water tank to the flushing device of the sanitary element for supplying grey water from the grey water tank to the flushing device; a filter assembly arranged in the interior of the grey water tank, which is connected to the interior of the grey water tank on the flow inlet side and to the grey water flushing line on the flow outlet side for pumping the grey water from the interior of the grey water tank through the filter assembly into the grey water flushing line; a grey water pump.which is designed and arranged to pump greywater from the interior of the greywater tank, which is under ambient pressure, through the filter device via the greywater flushing line to the flushing device.

11. Sanitary unit according to claim 10, characterized by a solids discharge opening on a section of the greywater tank located at the bottom in the direction of gravity, an actuator-operated solids shut-off valve for blocking and releasing the flow from the solids discharge opening, Control device designed to actuate the solids shut-off valve to allow flow through the solids discharge opening and to discharge solids from the lower section of the greywater tank through the solids discharge opening from the greywater tank.

12. Sanitary unit according to claim 11, characterized in that the sanitary element is connected to a wastewater collection tank via a wastewater pipe for the removal of wastewater and the solids removal opening is connected to the wastewater pipe via a solids removal pipe for introducing the solids into the wastewater pipe and conveying the solids through the wastewater pipe to the wastewater collection tank.

13. Sanitary unit according to claim 12, characterized by an intermediate container connected to the sanitary element via a wastewater intermediate line for drawing wastewater from the sanitary element into the intermediate container, a vacuum source connected to the intermediate container via a vacuum line for creating a vacuum in the intermediate container, a wastewater intermediate valve arranged between the sanitary element and the intermediate container, a control device configured to close the wastewater intermediate valve while a vacuum is being created in the intermediate container, and to open the wastewater intermediate valve after a vacuum has been built up in the intermediate tank for a rapid suction of the wastewater from the sanitary unit into the intermediate tank, further characterized in that the interior of the intermediate tank and the interior of the greywater tank are arranged adjacent to each other in such a way that they are separated from each other at least in one area by a partition wall which deforms under the build-up and release of the negative pressure in the intermediate tank and thereby causes pressure changes in the interior of the greywater tank which cause solids adhering as a filter cake to detach from the filter arrangement.

14. Sanitary unit according to claim 12 or 13, characterized by an intermediate tank connected to the sanitary element via a wastewater intermediate line for temporarily storing the wastewater from the sanitary element in the intermediate tank, a pressure source connected to the intermediate tank via a pressure line for building up pressure in the intermediate tank, a wastewater valve arranged between the intermediate tank and the wastewater collection tank for blocking and releasing the wastewater flow through the wastewater line, a control device configured to block the wastewater valve while pressure is being generated in the intermediate tank and to open the wastewater valve after pressure has been built up in the intermediate tank for rapidly forcing the wastewater out of the intermediate tank into the wastewater collection tank, further characterized in thatthat the interior of the intermediate tank and the interior of the greywater tank are arranged adjacent to each other in such a way that they are separated from each other, at least in one area, by a partition wall which expands and contracts under the build-up and release of overpressure in the intermediate tank. The holder becomes deformed, causing pressure changes inside the grey water tank, which lead to the detachment of solids adhering as a filter cake from the filter arrangement.

15. Sanitary unit according to claim 14, characterized in that the solids discharge line opens into the wastewater line in such a way that a fluid flow directed into the wastewater collection tank causes a suction effect on the solids discharge line and that the control device is designed to open a solids shut-off valve closing the solids discharge opening in temporal relation to the opening of the wastewater shut-off valve after the overpressure has built up, in order to suction solids from the greywater tank by means of the wastewater flowing through the wastewater line.

16. Sanitary unit according to one of the preceding claims 10-15, characterized in that the grey water tank and the intermediate tank are integrally formed, in that the grey water tank and the intermediate tank have an outer tank wall enclosing the interior spaces of both tanks and the partition wall is arranged in a space enclosed by this outer tank wall.

17. Sanitary unit according to one of the preceding claims 10-16, characterized by a water quantity sensor which is designed and arranged to determine a quantity of water in the interior of the greywater tank and further characterized in that the control device is connected to the level sensor signal technology and is designed to determine whether the determined quantity of water is sufficient to carry out a flushing process of the sanitary unit by means of the flushing device and to control a fresh water shut-off valve to supply fresh water to the greywater tank if it is determined that the quantity of water is not sufficient for such a flushing process, wherein the fresh water is supplied via a fresh water line opening into the filter device, is guided through the filter device into the interior of the flushing water tank and thereby flows through the filter device in a flow direction.which is opposite to the flow direction of grey water from the interior to the flushing device, preferably the fresh water pipe supplies the fresh water to the grey water tank at least sectionally by gravity with a drop height of at least 3 times the diameter of the fresh water pipe.

18. Sanitary unit according to one of the preceding claims 10-17, characterized in that a filter cleaning line branches off from the flushing line downstream of the grey water pump and is fed to a filter cleaning nozzle, and furthermore a filter cleaning valve is provided which can block or release the flow through the filter cleaning line, and that preferably the filter cleaning nozzle is arranged to discharge the grey water into the filter device in such a way that it flows through the filter device against the flow direction of the grey water from the interior of the grey water tank to the grey water pump.

19. Use of a sanitary unit according to one of the preceding claims 10-18 in such a way that the interior of the grey water tank is under ambient pressure, optionally is subjected to pulsed overpressure or underpressure by deformation of the partition wall, and that the grey water is drawn from the interior of the grey water tank by means of the grey water pump and pumped to the flushing device.

Images