water tank

Abstract

Water tank (10), comprising: a tank housing (12) with a tank interior (13) for receiving water (14), wherein the tank housing (12) has: at least one inlet opening (19) for introducing water (14) into the tank interior (13), at least one outlet opening (17) for draining water (14) from the tank interior (13), and a tank cap (18) on the water tank (10) when installed upper end of the tank housing (12); a float (30) which is freely movable in the interior of the tank (13) of the tank housing (12), wherein the float (30): an elongated buoy housing (301) with a buoy cover (304) at a first end and a buoy base (303) at a second end and has a truncated cone shape, wherein the buoy base (303) is at the narrower end face of the truncated cone shape and the buoy cover (304) is at the wider end face of the truncated cone shape, wherein the buoy cover (304) of the float (30) has a top surface (306) which is convex outwards, in its buoy cover (304) is provided with at least one detection element (32), and is designed such that its weight is less than the buoyant force of the water (14) in the tank interior (13) for it, wherein a length (Lb) of the float (30) is less than a minimum inner diameter (Dt) of the tank shell (12); and at least one sensor (28) arranged in the area of ​​the tank lid (18), wherein the at least one sensor (28) is configured to detect the at least one detection element (32) in the buoy cover (304) of the float (30), and the tank lid (18) has an inner lid profile (20) facing the interior of the tank (13), which is structured to guide the buoy cover (304) of the float (30) towards the at least one sensor (28), and the at least one detection element (32) in the buoy cover (305) of the float (30) has at least one magnetic element; and which has at least one sensor (28) in the area of ​​the fuel filler cap (18) and at least one magnetic sensor.

Description

[0001] The present invention relates to a water tank, in particular a water tank suitable as a grey water tank on board a vehicle.

[0002] Airplanes, ships, trains, and other vehicles have their toilets, handwashing sinks, galley sinks, and similar facilities connected to a water tank for the temporary storage of wastewater (also known as greywater). When the water tank reaches its maximum capacity, it is emptied, for example, by a vacuum disposal system. Various sensor systems are already available for monitoring the fill level. In practice, however, conventional water tanks frequently experience errors in level measurement, caused by deposits in the tank originating from the wastewater, which are essentially unavoidable.

[0003] From DE 101 62 257 A1, a device for holding at least two media is known, in which a float is provided at an interface between a liquid and a gas. The float's position above the bottom of a tank can be determined using this float.

[0004] WO 2009 / 000283A1 discloses a level transmitter in which several floating bodies float on the surface of a liquid in a tank.

[0005] From EP 2 738 528 A1, a measuring system is known with which a fill level in a tank can be determined. A floating body is also used for this purpose.

[0006] A conically shaped float is known from CN 2 01 740 549 U.

[0007] Further measuring systems for recording measurement data using floating bodies can be found in the publications DE 10 2017 126 128 A1 and DE 10 2020 114 771 A1.

[0008] The object of the invention is to create an improved water tank in which the level measurement is affected as little as possible by deposits.

[0009] This problem is solved by a water tank having the features of claim 1. Particularly advantageous embodiments and further developments of the invention are the subject of the dependent claims.

[0010] For the sake of simplicity, the term "water" will be used throughout. However, in the context of this revelation, the term is not to be understood solely as pure water, but rather as a synonym for liquids as well as mixtures of liquids and liquid-solid mixtures, i.e., emulsions, solutions, or suspensions, and in particular greywater, i.e., slightly polluted water.

[0011] A water tank according to the invention comprises a tank housing with an interior space for holding water (e.g., greywater), wherein the tank housing has at least one inlet opening for introducing water into the interior space, at least one outlet opening for discharging water from the interior space, and a tank lid at the upper end of the tank housing when the water tank is installed. The water tank further comprises a float (also referred to as a buoy) that is freely movable within the interior space of the tank housing, wherein the float has an elongated buoy housing with a buoy cover at a first end and a buoy base at a second end, is provided with at least one detection element in its buoy cover, and is designed such that its weight is less than the buoyant force exerted on it by the water in the interior space of the tank.Furthermore, the water tank has at least one sensor located in the area of ​​the tank lid and designed to detect the at least one detection element in the buoy cover of the floating body.

[0012] Because the weight of the float is less than the buoyant force of the water inside the tank, the float can rise towards the tank lid. This allows the sensor (which can also be called a level sensor) to detect the maximum water level in the tank by sensing the detection element in the float's buoy-shaped cover. This maximum level should then trigger the emptying of the tank. Alternatively, the sensor can be located outside the tank, on or in the tank lid, thus protecting it from deposits from the water inside the tank. This has the advantage of reducing the risk of the maximum water level being affected by deposits.In this context, the volume of the float is preferably chosen such that approximately 5 to 10% of the float, i.e., in particular the buoy cover, protrudes from the water. This ensures that the sensor's detection of the maximum fill level of the water tank is not impaired by water between the detection medium and the sensor.

[0013] Due to the elongated shape of the buoy housing and the free movement of the float within the tank housing, the float can remove deposits from its outer surfaces and the inner surfaces of the tank housing itself, even during normal operation. This occurs because the float rotates due to turbulence and eddies in the water tank, for example, during filling or emptying, creating a movement between the float and the inside of the tank housing. This relative movement removes deposits from both surfaces. During emptying, this cleaning effect can be enhanced by the airflow.This automatic cleaning of the water tank ensures that the water level measurement is at least less affected, or even not affected at all, by deposits from the water inside the tank, even without additional regular cleaning measures.

[0014] The tank housing is preferably essentially cylindrical, although it may preferably be slightly conical. The conical shape is such that the tank interior is narrower at the bottom than at the cap. The tank interior has a volume of, for example, approximately 1 to 1.5 liters. The tank housing is, for example, injection-molded, preferably from a glass fiber reinforced plastic.

[0015] A valve assembly with a drain valve for selectively opening or closing the outlet of the tank housing is preferably provided at the outlet opening, whereby the water tank of the invention can, in principle, be used in combination with any valve assembly. The inlet opening of the tank housing can be equipped with or without an inlet valve. In one embodiment of the invention, the inlet opening is located in the upper region of the tank housing, preferably in the tank lid, and the outlet opening is located in the lower region of the tank housing, preferably in the tank base, in each case with reference to the installed state of the water tank.

[0016] In one embodiment of the invention, the length of the float is smaller than the minimum inner diameter of the tank housing. This prevents the float from becoming jammed against the outer walls of the tank housing.

[0017] In one embodiment of the invention, a counterweight is located in the buoy housing of the float in the area of ​​the buoy base, the weight of which is greater than the weight of the buoy cover with the at least one detection element. This ensures that the float always floats with the buoy cover leading upwards towards the fuel tank cap, so that the detection element in the buoy cover is always directed towards the sensor in / on the fuel tank cap. The counterweight can, for example, be made of metal such as stainless steel.

[0018] In one embodiment of the invention, the outlet opening of the tank housing is coupled to a suction device. In this way, when the water tank is emptied, the water does not only slowly drain from the tank interior, but is also suctioned out. This causes greater turbulence of the water inside the tank and thus stronger movements of the float, resulting in a more effective cleaning action against deposits. The suction device can, for example, be part of a vacuum disposal system or include a water pump.

[0019] In one embodiment of the invention, the float has a truncated cone shape, with the buoy base located at the narrower end face of the cone and the buoy cover at the wider end face. The truncated cone shape thus resembles the design of an ice cream cone. This shape of the float (preferably enhanced by the conical shape of the tank housing) promotes turbulence of the water within the tank and thus the movement of the float, thereby increasing the cleaning effect.

[0020] The buoy housing of the float is preferably made of an impact-resistant material so that it is not susceptible to shocks. This prevents damage to the float when it collides with the tank housing. The impact-resistant material is, for example, a plastic material such as polyamide.

[0021] In one embodiment of the invention, the tank lid has an inner profile facing the tank interior, which is structured to guide the buoy-shaped cover of the float towards a central longitudinal axis of the tank housing. This achieves at least a near-central positioning of the float within the tank interior, which supports / enhances the movement of the float during turbulence in the water and thus promotes the cleaning effect. Furthermore, this allows the upper end of the float with the buoy-shaped cover to be directly rinsed by incoming water and thus cleaned of deposits (if the water tank's inlet opening is located in the upper region of the tank housing).

[0022] Additionally or alternatively, the inner profile of the tank lid is structured to guide the buoy cover of the float towards at least one sensor. This facilitates level measurement.

[0023] Preferably, the buoy cover of the float has an outwardly convex top surface. This shape of the buoy cover can assist in guiding the float through the inner profile of the tank lid.

[0024] In one embodiment of the invention, the at least one detection element in the buoy cover of the float comprises at least one magnetic element, and the at least one sensor (level sensor) in the area of ​​the tank lid comprises at least one magnetic sensor. The magnetic sensor system thus formed for detecting the water tank level is particularly advantageous because the magnetic field lines can penetrate the housings of the water tank and the float, as well as any deposits on them, without loss. This means that the detection of the water tank level is hardly or not at all affected by deposits. Furthermore, the magnetic sensor system allows the sensor to be placed outside the tank interior, thus preventing deposits from forming directly on the sensor. The level sensor is, for example, a Hall sensor or a capacitive sensor.

[0025] In this embodiment, the at least one detection element preferably has a ring magnet in the radial outer area of ​​the buoy cover. This type of detection element allows for reliable detection with only one magnetic sensor at only one position in / on the tank cover, regardless of the current orientation of the float. Furthermore, in this embodiment, the tank cover and the buoy cover are preferably each made of a non-ferromagnetic material or designed to be non-ferromagnetic in order to prevent interference with the float. The tank cover and buoy cover can optionally be made of the same or different materials. The non-ferromagnetic material could be, for example, a plastic, copper, or aluminum.

[0026] Within the scope of the invention, other sensor systems (e.g. optical, electromagnetic, etc.) with corresponding detection elements in / on the float can also be used in principle.

[0027] The water tank described above can be used particularly advantageously as a grey water tank on board a vehicle. The vehicle can be, in particular, an aircraft, a ship, or a train, but also another type of vehicle. Depending on the type and design of the vehicle, the grey water tank is connected at its inlet end, for example, to a toilet, a hand basin, a galley sink, or the like.

[0028] The above features and advantages of the invention, as well as others, will become clearer from the following description of a preferred, non-limiting embodiment with reference to the accompanying drawing. This drawing shows, partly schematically: Fig. 1 a longitudinal sectional view of a water tank according to an embodiment of the invention; Fig. 2A a perspective top view of a tank lid for the water tank of Fig. 1 according to an embodiment of the invention; Fig. 2B a longitudinal section view of the fuel tank cap of Fig. 2A; and Fig. 3 a longitudinal sectional view of a float for the water tank of Fig. 1 according to an embodiment of the invention.

[0029] Referring to Fig. 1, Fig. 2 to Fig. Section 3 now explains in more detail an example of a water tank. This water tank is, for example, a grey water tank on board an aircraft.

[0030] The water tank 10 has a tank housing 12 with a tank interior 13 for holding grey water 14 or other liquids or mixtures of liquids or liquids and solids. As in Fig. As can be seen in Figure 1, the tank housing 12 has a substantially cylindrical shape, but is also somewhat conical. The basic shape of the tank housing 12 is primarily formed by an outer wall 15 and has a longitudinal axis Xt. The tank interior 13 has, for example, a volume of approximately 1 to 1.5 liters. The tank housing 12 is made, for example, of a glass fiber reinforced plastic.

[0031] In the lower area of ​​the water tank when installed (at the bottom in Fig. 1) The tank housing 12 has a tank bottom 16, which is formed integrally with the outer wall 15 or is firmly connected to the outer wall 15. A drain opening 17 is provided in the tank bottom 16, through which water 14 can be drained from the tank interior 13. The drain opening 17 is, for example, positioned coaxially with the longitudinal axis Xt of the tank housing 12. The drain opening 17 is connected to a drain line 22 via a drain valve 23. The drain line 22, and thus the drain opening 17, is also coupled to a vacuum disposal system, which serves as a suction device 24 for extracting the water 14 from the tank interior 13.

[0032] In the upper area of ​​the water tank when installed (top in Fig. 1) The tank housing 12 has a tank lid 18, which in this embodiment is designed as a separate element and is firmly connected to the outer wall 15 of the tank housing 12. As in Fig. 2A and Fig. As shown in Figure 2B, the tank cap 18 has, for this purpose, for example, a few mounting elements 183, via which it can be screwed to the outer wall 15, for example.

[0033] As from Fig. 1, Fig. 2A, Fig. As shown in Figure 2B, the tank lid 18 has a lid body 182 on which the mounting elements 183 are provided and through which an inlet channel 185 leads, essentially coaxial to the longitudinal axis Xt of the tank housing 12, to an inlet opening 19 in the tank interior 13. A connection nozzle 184 is provided on the upper side of the tank lid 18, facing away from the tank interior 13, to allow a supply line to be connected to the water tank 10. In contrast to the lower outlet opening 17, this upper inlet opening 19 is always open.

[0034] The tank cap 18 further has a recess 186 on its outer surface for receiving a sensor 28. The sensor 28 is thus separated from the interior 13 of the water tank 10. The sensor 28 is preferably a magnetic sensor, for example a Hall sensor.

[0035] Furthermore, the tank cap 18 has a special inner profile 20 on its inner surface facing the tank interior 13. The inner profile 20 has a special structure that concentrates access from the tank interior 13 to the tank cap 18 on the central area of ​​the longitudinal axis Xt and the inlet opening 19. As in Fig. 2A and Fig. As illustrated in Figure 2B, the inner cover profile 20 can be formed for this purpose from several guide lamellae 188, which are oriented radially with respect to the longitudinal axis Xt and extend deeper into the interior of the tank 13 on the outside than in the area of ​​the inlet opening 19.

[0036] Inside the tank housing 12 is a float 30, which can also be referred to as a buoy. This float 30 is freely movable within the tank interior 13, i.e., it is not fixed to any component of the tank housing 12.

[0037] As in Fig. 1 and Fig. As shown in Figure 3, the floating body 30 preferably has a hollow truncated cone shape, similar to an ice cream cone. When floating in the water 14, the truncated cone shape is narrower at the bottom than at the top.

[0038] The truncated conical shape of the float 30 is formed in particular by a buoy housing 301, which has an outer wall 302, a buoy base 303, and a buoy cover 304. The buoy cover 304 is attached to the outer wall 302, for example, by an adhesive bond 305, while the buoy base 303 is formed integrally with the outer wall 302. The buoy housing 301 has a longitudinal axis Xb.

[0039] A detection element 32 in the form of a ring magnet is arranged in the buoy cover 304. This ring magnet 32 ​​can be detected by the magnetic sensor 28 on the tank lid 18. The buoy cover 304 is therefore preferably made of a non-ferromagnetic material, for example, a plastic material. The outer wall 302 and the buoy base 303 can also be made of a plastic material. Preferably, an impact-resistant plastic material, such as a polyamide, is chosen for the buoy housing 301 so that the float 30 is shock-resistant.

[0040] In this embodiment, the upper surface 306 of the buoy cover 304 is convexly curved outwards. This allows the buoy cover 304 to be guided particularly effectively from the inner profile 20 of the tank lid 18 to the center of the tank lid 18. As a result, the ring magnet 32 ​​in the buoy cover 304 is moved particularly close to the sensor 28 on the tank lid 18 when the water tank 10 is at its maximum fill level, enabling reliable detection of the maximum fill level.

[0041] In the area of ​​the buoy base 303, a counterweight 308 (for example, made of metal, such as stainless steel) is incorporated into the buoy housing 301. The weight of the counterweight 308 is greater than the weight of the buoy cover 304 including the ring magnet 32, so that the float 30 is heavier in the base area than in the cover area. This causes the float 30 to orient itself in the water 14 so that its buoy cover 304 faces the tank lid 18, as shown in Fig. Figure 1 illustrates this. Furthermore, the float can thus be essentially coaxially aligned with the tank housing 12 in the water 14. In this way, the buoy cover 304 with its ring magnet 32 ​​is reliably guided to the center of the inner cover profile 20 of the tank cover 18 as the water level rises in the tank interior 13.

[0042] The total volume and weight of the float 30 are also designed such that its weight is less than the buoyant force of the water 14 inside the tank 12. The buoyant force is, for example, about 15% greater than the weight, so that about 5-10% of the float 30 protrudes from the water 14. This keeps the buoy cover 304 uncovered by water, ensuring that detection is not disrupted by water 14 or deposits between the magnetic sensor 28 and the ring magnet 32.

[0043] As in Fig.As illustrated in Figure 1, the length Lb of the float 30 is significantly smaller than the height Lt of the tank interior 13, and the maximum outer diameter Db of the float 30 is significantly smaller than the minimum inner diameter Dt of the tank interior. Furthermore, the length Lb of the float 30 is smaller than the minimum inner diameter Dt of the tank housing 12. These dimensions ensure that the float 30 can move freely within the tank interior 13 and cannot become jammed against the outer wall 15 of the tank housing 12. Additionally, the float 30 should also be wider at its buoy base 303 than the outlet opening 17 in the tank base 16 to prevent the float 30 from becoming jammed in the outlet opening 17.

[0044] In addition to the generally known functionality of a grey water tank, this water tank 10 also has an effect of self-cleaning the tank housing 12 and the float 30 from deposits from the grey water 14. This cleaning effect occurs as follows.

[0045] Both when water 14 enters and when water 14 flows out of the tank interior 13, turbulence is created in the water 14. This turbulence causes the float 30 to rotate within the tank interior 13. This movement between the float 30 and the tank housing 12 removes deposits from the inner surfaces of the tank housing 12 and the outer surfaces of the float 30. When the water tank 10 is emptied, the turbulence of the water 14 is further intensified by the use of the suction device 24, and the loosened deposits are completely removed from the tank interior 13 along with the water 14. Furthermore, air currents are generated during emptying by suction from the inlet opening 19, which further intensify the turbulence within the tank interior 13.Furthermore, even at a constant fill level, turbulence can occur in the water 14 if the vehicle (especially in the case of an aircraft) is moving. This turbulence is further exacerbated by the asymmetrical designs of the tank housing 12 and the buoy housing 301. And due to the central positioning and orientation of the float 30, the water 14 from the inlet opening 19 also directly impacts the buoy cover 304 protruding from the water 14, thus also removing deposits from the buoy cover 304.

[0046] This automatic removal of deposits ensures the reliability of the sensor's detection of the maximum fill level, without the need for regular cleaning of the water tank 10.

[0047] The special design of the water tank 10 also improves the functionality of the sensors. By positioning the sensor 28 outside the tank interior 13, no water 14, liquid, or deposits from the water 14 or liquid can reach the sensor 28. Because the buoy cover 304 protrudes from the water 14, no water 14 or deposits are present between the sensor 28 and the detection element 32, which would impair the measurement. The use of a magnetic sensor as described above also has the advantage that the magnetic field lines are not normally blocked or weakened by deposits, thus increasing the reliability of the detection even in the presence of deposits. REFERENCE NUMBER LIST 10 water tank 12 tank housings 13 Tank interior 14 Water 15 Exterior wall 16 Tank bottom 17 Outlet opening 18 Fuel tank caps 182 lid bodies 183 Mounting element 184 connection pieces 185 Inlet channel 186 Recess for sensor 188 guide vanes 19 Inlet opening 20 Lid inner profile 22 Outlet pipe 23 Drain valve 24 Extraction device 28 Sensor 30 floats / buoy 301 buoy housings 302 Exterior wall 303 Buoy bottom 304 buoy covers 305 Adhesive bond 306 Top 308 Countermass 32 Detection element dB maximum outer diameter of the buoy 30 Dt minimum inner diameter of the tank housing 12 Buoy length 30 Lt Height of the tank interior 13 Xb Longitudinal axis of buoy 30 Xt Longitudinal axis of the tank housing 12

Claims

Water tank (10), comprising: a tank housing (12) with a tank interior (13) for receiving water (14), wherein the tank housing (12) comprises: at least one inlet opening (19) for introducing water (14) into the tank interior (13), at least one outlet opening (17) for discharging water (14) from the tank interior (13), and a tank lid (18) at the upper end of the tank housing (12) when the water tank (10) is installed;a floating body (30) which is freely movable within the interior of the tank (13) of the tank housing (12), wherein the floating body (30): has an elongated buoy housing (301) with a buoy cover (304) at a first end and a buoy base (303) at a second end and has a truncated conical shape, wherein the buoy base (303) is located at the narrower end face of the truncated conical shape and the buoy cover (304) is located at the wider end face of the truncated conical shape, wherein the buoy cover (304) of the floating body (30) has an upper surface (306) which is convex outwards, is provided in its buoy cover (304) with at least one detection element (32), and is designed such that its weight is less than the buoyant force of the water (14) in the interior of the tank (13) for it, wherein a length (Lb) of the float (30) is smaller than a minimum inner diameter (Dt) of the tank housing (12);and at least one sensor (28) arranged in the area of ​​the tank lid (18), wherein the at least one sensor (28) is configured to detect the at least one detection element (32) in the buoy cover (304) of the float (30), and the tank lid (18) has an inner lid profile (20) facing the interior of the tank (13), which is structured to guide the buoy cover (304) of the float (30) towards the at least one sensor (28), and the at least one detection element (32) in the buoy cover (305) of the float (30) has at least one magnetic element; and the at least one sensor (28) has at least one magnetic sensor in the area of ​​the tank lid (18). Water tank (10) according to claim 1, in which a counterweight (308) is located in the buoy housing (301) of the float (30) in the area of ​​the buoy bottom (303), wherein the weight of the counterweight (308) is greater than the weight of the buoy cover (304) with the at least one detection element (32). Water tank (10) according to one of the preceding claims, wherein the outlet opening (17) of the tank housing (12) is coupled to a suction device (24). Water tank (10) according to one of the preceding claims, wherein the buoy housing (301) is made of an impact-resistant material. Water tank (10) according to one of the preceding claims, wherein the tank lid (18) has an inner lid profile (20) facing the interior of the tank (13), which is structured to guide the buoy cover (304) of the float (30) in the direction of a central longitudinal axis (Xt) of the tank housing (12). Water tank (10) according to one of the preceding claims, wherein the at least one detection element (32) has a ring magnet in the radial outer area of ​​the buoy cover (304). Water tank (10) according to one of the preceding claims, wherein the tank lid (18) and the buoy lid (304) are each made of a non-ferromagnetic material. Water tank (10) according to one of the preceding claims, wherein the at least one sensor (28) is arranged in the area of ​​the tank lid (18) outside the tank interior (13). Use of the water tank (10) according to one of the preceding claims as a grey water tank on board a vehicle.

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