Inlet unit and safety fitting for an open tank and device for connection to the drinking water network

Abstract

An inlet unit (10) for an open tank (60) for receiving a liquid or for a safety fitting (40) for an open tank (60), comprising a cover (16) having an inlet opening (18) which can be connected to an inlet for liquid such that liquid from the inlet enters the inlet unit (10), an inner row (30) of inner louvers (32) spaced apart from each other and arranged around the inlet opening (18) and extending away from the cover (16), an outer row (20) of outer louvers (22) spaced apart from the inner row (30), spaced apart from each other and arranged around the inlet opening (18) and extending away from the cover (16), and an outer wall (12) with overflow openings (14) which is covered by the cover (16) and surrounds the outer row (20) of outer louvers (22).The inner row (30) of inner louvers (32) is arranged closer to the inlet opening (18) than the outer row (20) of outer louvers (22). The outer louvers (22) overlap with the inner louver openings (38) formed between the inner louvers (32) such that the inner louver openings (38) are covered by the outer louvers (22) in the direction of the inlet opening (18).

Description

[0001] The present invention relates to an inlet unit for an open tank for receiving a liquid and a safety fitting comprising an inlet unit for an open tank. The inlet unit has an outer wall and a cover with an inlet opening that can be connected to a liquid inlet such that liquid flows from the inlet into the inlet unit.

[0002] Devices and appliances that are directly or indirectly connected to the drinking water network or another liquid network require a safety device that reliably prevents backflow into the water or liquid network. This is regulated, for example, in standards such as EN 1717.

[0003] Categories 4 and 5 of EN 1717 prescribe the corresponding measures. These apply, for example, to reverse osmosis systems, particularly those used in the medical field. The required safety mechanisms can generally only be ensured via a free inlet with a suitable overflow. This also applies to systems with low flow rates and small containers (less than 1 m³).

[0004] Typically, devices connected to a fluid network use a buffer tank or reservoir to hold the fluid for downstream components such as pumps. This type of tank is positioned downstream of a safety valve, which protects the fluid or water network from backflow, backsiphonage, and / or backpressure of fluid from a device or tank. This reliably prevents the risk of contamination of the fluid network by potentially contaminated fluid from a device or tank.

[0005] Implementing the required safety measures, particularly with smaller devices, presents challenges. Due to the low fluid flow rates, small hoses and tank units or pre-tanks are used. Nevertheless, the minimum clearances for the fluid containment of the system must be maintained, especially if a free inlet is used. This often results in the introduced fluid splashing over the edge of the pre-tank or tank.

[0006] In many devices, especially medical devices, the tank units or containers are mounted inside the device. This means that if liquid splashes over the edge of the container during operation, it can lead to liquid accumulation inside the device and permanent damage. Furthermore, if the devices are installed in sensitive areas, permanent contamination by liquid is neither acceptable nor desirable with externally mounted tank units.

[0007] In the prior art, inlet units with injectors or similar devices are therefore used to reduce splashing or overflowing beyond the container edge. However, this leads to turbulence within the tank, which can cause damage to the equipment, especially to downstream components such as pumps, if these draw in air bubbles due to the turbulence.

[0008] US 4 467 830 A, for example, shows an inlet unit for an open liquid tank or a safety fitting for an open tank.

[0009] The inlet units available in the state of the art, which meet the legal and normative requirements regarding the prevention of backflow into a liquid network, are generally designed for large appliances and are unsuitable for small appliances. Some of these units also lack sufficient splash protection, so damage to the appliances due to liquid accumulation is a recurring problem.

[0010] The object of the present invention is therefore to propose an inlet unit or safety fitting that provides splash protection and avoids turbulence in an open tank during free inlet.

[0011] The problem is solved with an inlet unit having the features of claim 1, a safety fitting having the features of claim 2, an open tank for connection to a liquid network having the features of claim 12, and a device for connection to the drinking water network having the features of claim 15.

[0012] In one aspect, the present invention relates to an inlet unit for an open tank for receiving a liquid or for a safety fitting for an open tank. The inlet unit according to the invention has a cover with an inlet opening which can be connected to a liquid inlet such that liquid flows from the inlet into the inlet unit. The inlet can preferably be implemented as a free inlet or in the form of a hose or pipe.

[0013] The inlet unit has an inner row of (web-shaped) inner louvers, spaced apart from each other and arranged around the inlet opening and extending away from the ceiling, and an outer row of (web-shaped) outer louvers spaced apart from the inner row, arranged around the inlet opening and extending away from the ceiling.

[0014] An outer wall of the inlet unit has at least one overflow opening. The outer wall is covered by and connected to the ceiling. It surrounds the outer row of outer louvers. The inner row of inner louvers is positioned closer to the inlet opening than the outer row of outer louvers, and the outer louvers overlap with the inner louver openings formed between the inner louvers in such a way that the inner louver openings are covered by the outer louvers in the direction of the inlet opening.

[0015] In another aspect, the invention relates to a safety fitting for an open tank for receiving a liquid, comprising an inlet unit that can be connected to an inlet for the liquid and a downwardly open dip tube adjoining the inlet unit.

[0016] The inlet unit comprises a cover with an inlet opening. The inlet opening is connectable to the inlet such that liquid flows from the inlet into the inlet unit. The inlet unit has an inner row of internal fins, spaced apart from each other and arranged around the inlet opening, extending away from the cover, and an outer row of external fins, spaced apart from the inner row, also arranged around the inlet opening and extending away from the cover. The inlet unit of the safety valve has an outer wall with overflow openings, which is covered by the cover and surrounds the outer row of external fins. The inner row of internal fins is positioned closer to the inlet opening than the outer row of external fins, and the external and inner fins are arranged to overlap from the direction of the inlet opening.

[0017] According to the invention, the lamellae of the inlet unit are arranged such that every straight jet of liquid from the inlet opening laterally outwards towards the outer wall strikes at least one lamella and cannot splash out laterally from the inlet unit. This has the advantage that lateral escape of liquid from the inlet unit during the liquid inlet process is reliably prevented, since the offset arrangement of the lamellae prevents the liquid from escaping laterally. Consequently, the liquid flows from the inlet through the inlet unit downwards into a connected tank. In this way, a free inlet without lateral splashing can be achieved. The escape of splashing liquid directly from the inlet beyond the tank is prevented. Thus, wetting of surrounding surfaces with liquid is prevented.

[0018] The overflow openings in the outer wall ensure venting of the dip tube connected to the inlet unit. This prevents liquid from flowing back from the dip tube, which is immersed in a tank, into the inlet opening. This fulfills the relevant regulatory requirements that mandate preventing backflow into a liquid or water network connected to the inlet opening via an inlet.

[0019] A device with such an inlet unit is protected from damage caused by splashing liquid. Furthermore, it complies with legal and regulatory requirements for safety fittings in apparatus and equipment. Turbulence in the tank or pre-tank is reduced to a minimum or completely prevented, thus eliminating the possibility of damage to the device.

[0020] In another aspect, the invention relates to an open tank for connection to a liquid network, with a safety fitting as described above. The tank comprises an outlet located in the bottom of the tank and a retaining device for holding the safety fitting to the tank or an open housing of the tank. Optionally, the outlet can also be located in the lower region on a wall of the tank.

[0021] According to the invention, the open tank or pre-tank is suitable for use with a free inlet, through which liquid or water flows into the tank from a liquid or water network. The liquid is directed from an inlet into the tank via the safety valve. The liquid can drain out, be pumped out, or be suctioned out via the outlet in the bottom of the tank. In the event of a malfunction, such as a defective outlet and a continued inflow of liquid, the safety valve prevents backflow into the liquid network and allows the liquid to overflow the top edge of the open tank.

[0022] In another aspect, the invention relates to a device for connection to the drinking water network, in particular a dialysis machine or a reverse osmosis machine. The device has an open tank for receiving water, a free inlet into the tank by means of an inlet, and a safety fitting as described above to prevent lateral escape of the supplied water during inlet to the tank. The dip tube of the safety fitting, which is connected to the inlet unit, projects into the tank such that the free end of the dip tube is spaced away from the bottom of the tank.

[0023] Preferred embodiments of the invention are described in the dependent claims. It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the present invention.

[0024] In a preferred embodiment, the inner row of internal slats and the outer row of external slats in the feed unit are arranged essentially on a closed curved track. The two curved tracks are particularly preferably concentric. The curved track is very preferably a curved path, for example, an oval or a circle. A circular arrangement of the slats has the advantage of being very easy to manufacture. However, oval arrangements of the inner and outer rows of slats may be advantageous for some devices.

[0025] The outer wall of the inlet unit preferably also has the form of a closed curved track, which is particularly preferably arranged concentrically to the outer row of outer louvers. A circular outer wall is advantageous when the louvers are arranged in a circle.

[0026] Another preferred embodiment provides that the spacing between the inner louvers and / or the spacing between the outer louvers is equal. The individual louvers of the respective rows then have equidistant spacing. In a particularly preferred embodiment, the spacing between the inner louvers is the same as the spacing between the outer louvers. Of course, there may be embodiments and applications in which the spacing between the outer louvers and the spacing between the inner louvers are unequal. It is also conceivable that the spacing of the louvers in the respective rows can vary. The size, in particular the width, of the inner louvers can also differ from the size or width of the outer louvers.

[0027] A preferred embodiment of the inlet unit provides that the inlet opening is centrally located in the lid. In this case, the louvers are preferably arranged concentrically to the central opening in the lid. This is particularly advantageous when the closed curved path of the outer and inner louvers is circular and the outer wall is also circular and concentric to the inlet opening. Preferably, the outer louvers and / or the inner louvers are slightly curved.

[0028] In a further preferred embodiment of the inlet unit, the louvers (inner louvers or outer louvers) are integrally connected to the ceiling. Particularly preferred is the integral connection of the louvers and the ceiling to the outer wall.

[0029] Particularly preferred are the outer slats or the inner slats each of the same width. An equally preferred embodiment provides that the outer slats and / or inner slats are each of the same length. However, in some embodiments it may be advantageous for the inner slats to be longer than the outer slats. This is especially true if the inner slats are connected to each other at their free underside by means of a connecting ring (inner ring). It is also preferred if the outer slats are the same width as the inner slats.

[0030] A particular embodiment of the inlet unit provides a lower base ring opposite the top and featuring an inner opening, allowing liquid from the top or the inlet opening to flow directly through this opening. Preferably, the base ring is connected to the outer wall. It is also preferred that the outer fins are connected to the base ring at their lower free ends. This increases the stability of the fins. Of course, these features can also be implemented individually. For example, the base ring can be connected to the outer fins, but it does not have to be connected to the outer wall. The arrangement of a base ring connected to the outer wall is particularly advantageous for an inlet unit that is otherwise completely open at its lower end.

[0031] Preferably, the inner lamellae are connected to each other at their lower ends by a lower inner ring. The inner ring has a width at least equal to the thickness of one lamella. The inner ring can be connected to the lower bottom ring at least via webs, the bottom ring preferably being integrally connected to the outer wall.

[0032] In a preferred embodiment, the overflow openings in the outer wall are dimensioned such that the sum of the widths of the overflow openings is greater than the sum of the opening widths in the inner row between adjacent inner louvers, or greater than the sum of the opening widths in the outer row between adjacent outer louvers. Thus, the sum of the widths of the overflow openings is greater than the sum of the widths of the inner louver openings formed between two adjacent inner louvers. The same applies to the opening widths of the outer louver openings between the outer louvers. This ensures that no backflow can occur. Rather, any amount of liquid that penetrates the louvers of the inner and outer rows can flow out through the outer wall.

[0033] Inner and outer louver openings form gaps between the respective louvers. If an inner ring and a bottom ring are present, opening windows are formed between the louvers, framed by two adjacent louvers, the top, and the corresponding ring at the bottom of the inlet unit.

[0034] In a preferred embodiment, the inlet unit is designed for small inlet volumes. Preferably, the inlet opening is dimensioned such that the flow velocities through an inlet installed at the inlet opening are significantly less than 1 m³ per hour. More preferably, the flow velocity is limited to less than 0.5 m³ per hour, and very preferably to less than 0.1 m³ per hour. A particularly preferred embodiment provides an inlet opening that allows a flow velocity of at most 0.05 m³ per hour.

[0035] In a preferred embodiment of the safety fitting, the inner lamellar openings between each pair of inner lamellae have a height that is greater than a normatively specified overflow height Ow. This can be found, for example, in standard EN 1717.

[0036] In a preferred embodiment of the safety fitting, the inlet unit and / or the dip tube have a circular cross-section. The diameter of the dip tube is at most the diameter of the outer wall and larger than the diameter of the inner row of the internal fins. In a preferred embodiment, the outer wall and / or an optional lower base ring is shaped to form a stop for the dip tube. Preferably, the outer wall, the base ring, or an inner ring for the internal fins can form a receptacle for the upper end of the dip tube. This receptacle can be secured to the inlet unit by a form fit, an interference fit, or a resilient retaining clip, such as an elastic collar. The retaining effect can be enhanced by additional fasteners or adhesives.

[0037] A collar is preferably arranged at the lower end of the outer wall, forming part of the receptacle for the immersion tube. The collar-shaped collar can be integrally molded onto the base ring.

[0038] The immersion tube can have a curved, oval, round or angular cross-section.

[0039] A preferred embodiment of the tank according to the invention provides that the tank volume is not greater than 1 m³. Further preferred are embodiments of the tank with a volume of less than 0.5 m³, at most 0.1 m³, and particularly preferably at most 0.01 m³. The safety fitting according to the invention is particularly suitable for tanks with smaller volumes, also to meet regulatory requirements.

[0040] In another preferred embodiment, the length of the dip tube is such that the dip tube extends into the tank at least to a minimum operating fluid level without touching the bottom of the tank. The operating fluid level is the level of liquid in the tank that is not undercut during normal operation. The operating fluid level only falls below this level in the event of a malfunction, when the inlet is blocked and the outlet is open.

[0041] In a preferred embodiment, the inlet unit has a housing that is at least partially open at the bottom, with an outer wall and a ceiling. This allows liquid or water to fall freely from the ceiling into a tank located below, thus preventing backflow towards the inlet.

[0042] Preferably, the lamellae (inner and outer lamellae) overlap at both edges. An outer lamella thus overlaps or protrudes with its edges the edges of two adjacent inner lamellae. The same applies to the inner lamellae vice versa. The overlap is such that every straight jet of liquid from the inlet opening, flowing laterally outwards towards the outer wall, strikes at least one lamella but does not reach the outer wall.

[0043] In another preferred embodiment of the inlet unit, the inlet opening has a connection area that interacts with a connection piece of an inlet in such a way that a liquid-tight connection is established between the inlet opening and the inlet or connection piece. The connection area can, for example, and preferably, have a thread (internal thread), a screw connection, a clip connection or clamp connection, an adhesive area, or a press-fit area.

[0044] The invention is described and explained in more detail below with reference to some selected embodiments in conjunction with the accompanying drawings. These show: Figures 1a, 1 show a cross-sectional view of the inlet unit according to the invention; Figure 2 shows a cross-sectional drawing of a safety fitting; Figure 3 shows a safety fitting in different views; Figures 4a - 4 show an open tank with a safety fitting in different views;

[0045] Figure 1a and 1b Figure 1 shows an inlet unit 10 for an open tank for receiving a liquid. The inlet unit 10 has an outer wall 12 with overflow openings 14, which allow liquid to escape from the interior of the inlet unit 10 to the outside. A cover 16 of the inlet unit 10 has an inlet opening 18, which is centrally located and serves for connection to an inlet through which liquid can flow into the inlet unit 10. In the embodiment shown here, the inlet opening 18 has an internal thread 19 into which an optional adapter can be screwed, for example, to connect an inlet hose to the inlet unit 10.

[0046] The ceiling 16 covers the outer wall 12, as does an outer row 20 with outer louvers 22, which extend from the ceiling 16 and are arranged parallel to the outer wall 12. The outer row 20 with the outer louvers 22 is arranged around the inlet opening 18. The individual outer louvers 22 are spaced apart from one another and together form a circular arrangement in the outer row 20, which extends coaxially around the inlet opening 18 located centrally on the ceiling 16.

[0047] Between the outer row 20 and the inlet opening 18, a circular inner row 30 of inner louvers 32 is arranged, which also extends from and is connected to the ceiling 16. The individual inner louvers 32 are spaced apart from each other. The inner row 30 is arranged coaxially to and between the outer row 20 and the inlet opening 18.

[0048] At the lower end of the outer lamellae 22, a base ring 24 is provided, which connects the individual outer lamellae 22 to each other. The base ring 24 transitions into the outer wall 12, which has a tapered diameter in the area of ​​the base ring 24 and transitions into a sleeve 26. The sleeve 26 is cylindrical and has a smaller outer diameter than the outer wall 12. The base ring 24 and sleeve 26 form a stop 28 for receiving a dip tube.

[0049] An inner ring 34 connects the inner slats 32 at their lower end. This increases the stability of the inner slats 32 in the inner row 30. The same applies to the bottom ring 24, which increases the stability of the outer slats 22 in the outer row 20.

[0050] The inner ring 34 has a downwardly extending collar 36, which is directed obliquely outwards. In this way, the outer diameter of the inner ring 34 increases downwards, i.e. in the direction away from the ceiling 16.

[0051] The inner ring 34 and the base ring 24 are spaced apart from each other. Both have an inner opening, with the inner ring 34 arranged in the inner opening of the base ring 24. The liquid entering the inlet unit 10 through the inlet opening 18 flows downwards through the inner opening of the inner ring 34.

[0052] In the BB cut in Figure 1bIt can be seen that the individual inner lamellae 32 are web-shaped and slightly curved. The inner lamellae 32 are of the same size and are spaced equally apart. Between each pair of adjacent inner lamellae 32, an inner lamella opening 38 is formed, which has an opening width such that the sum of all opening widths of the inner lamella openings 38 is smaller than the sum of all opening widths of the overflow openings 14.

[0053] The outer louvers 22 of the outer row 20 are all the same size, i.e., the same length and width, as are the inner louvers 32. Between each pair of adjacent outer louvers 22, an outer louver opening 23 is formed, all of which are the same size. The sum of all the opening widths of the outer louver openings 23 is less than the sum of the widths of the overflow openings 14 of the outer wall 12 and preferably at least as large as the sum of all the opening widths of the inner louver openings 38.

[0054] In the embodiment of Figure 1b The widths of the outer louver openings 23 are smaller than the widths of the outer louvers 22, with the opening widths preferably being 80% of the widths of the outer louvers 22. The same applies to the widths of the inner louver opening 38, which are smaller than the widths of the inner louvers 32, preferably by about 80%.

[0055] The cut in Figure 2Figure 1 shows a safety fitting 40 according to the invention, comprising an inlet unit 10 and a dip tube 50. The cylindrical dip tube 50 is attached to the cylindrical inlet unit 10, the diameter of the dip tube 50 being smaller than the diameter of the outer wall 12, and in particular smaller than the inner diameter of the sleeve 26 of the outer wall 12. The dip tube 50 has an inner diameter that is larger than the outer diameter of the collar 36 of the inner ring 34 on its lower side. This allows the dip tube 50 to be inserted into the receptacle formed by the sleeve 26, the stop 28, and the collar 36 until the upper end of the dip tube 50 abuts the stop 28. The dip tube 50 is held in place by the resulting press fit between the sleeve 26 and the collar 36.In a preferred embodiment of the safety fitting 40, both the dip tube 50 and the inlet unit 10 are made of plastic, so that an elastic clamping fit is formed between the sleeve 26 and the collar 36, which reliably holds the dip tube 50. Alternatively or additionally, the dip tube 50 could be glued or fastened by means of a screw that could extend through the sleeve 26 into the dip tube 50.

[0056] In a preferred embodiment of the safety fitting 40, all parts are made of a plastic that has high temperature resistance and can also come into continuous contact with liquids whose temperature is greater than 80°C, preferably greater than 90°C, and very preferably greater than 100°C. Furthermore, the plastic is selected to be resistant to disinfectants and other chemicals that correspond to the application area of ​​the safety fitting 40.

[0057] Figure 3The safety fitting 40 is shown Figure 2 in different representations.

[0058] In the sectional drawing BB of the Figure 3 It is clearly evident that water entering the inlet unit 10 through the inlet opening 18 cannot splash out laterally through the overflow openings 14. The outer louvers 22 of the outer row 20 and the inner louvers 32 of the inner row 30 are arranged to overlap each other. Water splashing radially outwards from the inlet opening 18 is always stopped by one of the louvers of the inner row 30 or the outer row 20. Thus, any jet of liquid 44 moving laterally outwards from the inlet opening 18 towards the outer wall 12 encounters an inner louver 32 or an outer louver 22 and therefore cannot escape directly through the overflow openings 14. This ensures that no incoming liquid splashes out laterally from the inlet unit 10.

[0059] In the sectional drawing AA in Figure 3 The safety fitting 40 indicates that the height of the inner louver opening 38 is greater than the height of the overflow opening 40. The same applies to the height of the outer louver opening 23. Preferably, the inner louver openings 38 and the outer louver openings 23 are higher than a regulated overflow height specified in standards such as EN 1717.

[0060] The overflow openings 14 not only serve to ensure an overflow that may be required in the event of a fault, but also serve to ventilate the immersion tube 50 of the safety fitting 40.

[0061] During operation, liquid or water beads up and splashes sideways at the lower edge of the inlet opening 18 inside the inlet unit 10. This occurs particularly with increasing service life, as deposits of, for example, hard water form. The laterally deflected water cannot completely pass through the fins of the inner row 30 and outer row 20 and thus drips down the inner fins 32 or the outer fins 22 into the dip tube 50. The openings in the inner ring 34 and the bottom ring 24 ensure a free fall path for the liquid from the inlet opening 18 downwards through the dip tube 50.

[0062] The Figures 4a to 4dFigure 1 shows a tank 60 that is open at the top and has a safety fitting 40 comprising an inlet unit 10 and a dip tube 50. The safety fitting 10 is attached to a U-shaped bracket 62, which is secured to the upper part of the tank 60 by its U-shaped legs. This can be, as shown in Figure 1, Figure 4a and 4b to be identified, for example by screws 64 which extend through the tank wall 66.

[0063] The cylindrically shaped safety fitting 40 extends through a circular receiving opening in the U-base 68 of the bracket 62. On the outside of the inlet unit, claws 42 extend outwards, ensuring that the safety fitting 40 cannot slip through the receiving opening in the U-base 68.

[0064] In the illustrated embodiment of the tank 60, a drain opening 70 is provided in the lower region of one of the side walls of the tank 60 to allow liquid to be drawn from the tank 60. For this purpose, a hose is typically connected to a pump to pump the liquid out of the tank 60. Alternatively, and preferably, the drain opening 70 can be located in the bottom 61 of the tank 60.

[0065] The tank 60 is preferably dimensioned such that its volume is less than 1 m³. Particularly for small tanks, with a volume less than 0.5 m³, and especially preferably with a volume of 0.1 m³ or less, such an embodiment with an open tank and safety fitting 40 is preferred.

[0066] As in the Figures 4a, 4b and 4dAs can be seen, the dip tube 50 extends into the tank 60. The length of the dip tube and the height of the support 62 are dimensioned such that a free end 52 of the dip tube is spaced away from the bottom 61 of the tank 60. Furthermore, the length of the dip tube 50 is dimensioned such that the free end 52 of the dip tube 50 reaches down to a minimum operating liquid level in the tank 60. This ensures that the dip tube 50 is always immersed in liquid when the tank 60 is operating normally. This prevents the formation of bubbles or air within the tank 60. The liquid flowing in through the inlet unit 10 and the dip tube 50 is not disturbed within the tank.

[0067] The materials used for tank 60 and safety fitting 40 are preferably chemically and temperature-resistant, particularly for temperatures above 70° Celsius. Connecting elements, inlet hoses, or outlet hoses connected to tank 60 or safety fitting 40 are preferably made of durable plastic such as PE. Due to its geometry, the inlet unit 10 is preferably manufactured using a 3D printing process, typically employing special plastics that are suitable for 3D printing and meet the requirements for chemical and temperature resistance. Some of the plastic parts, such as tank 60 or dip tube 50, can preferably be manufactured from standard materials, for example, PP.

[0068] Of course, it is also possible to design the tank 60 so that two safety fittings can be used in, for example, two adjacent brackets 60. This makes it possible to provide a dual liquid inlet to the tank. Preferably, such a tank 60 is installed in a medical device, for example, a reverse osmosis unit, for direct connection to a drinking water supply. By inserting the safety fitting 40, the drinking water network is protected.

[0069] The invention has been comprehensively described and explained with reference to the drawings and the description. The description and explanation are to be understood as examples and not as limiting. The invention is not limited to the disclosed embodiments. Other embodiments or variations will become apparent to a person skilled in the art when using the present invention and upon a detailed analysis of the drawings, the disclosure, and the subsequent claims.

[0070] In the claims, the words "comprise" and "with" do not preclude the presence of further elements. The undefined article "a" or "an" does not preclude the presence of multiple elements. A single element or unit can perform the functions of several of the units mentioned in the claims. The mere mention of some measures in several different dependent claims is not to be understood as precluding the advantageous use of a combination of these measures. Reference numerals in the claims are not to be interpreted restrictively.

Claims

1. Inlet unit (10) for an open tank (60) for receiving a liquid or for a safety fitting (40) for an open tank (60); comprising a cover (16) having an inlet opening (18) which can be connected to an inlet for liquid such that liquid flows from the inlet into the inlet unit (10); an inner row (30) of inner louvers (32) spaced apart from each other and arranged around the inlet opening (18) and extending away from the cover (16); an outer row (20) of outer louvers (22) spaced apart from the inner row (30), arranged around the inlet opening (18) and extending away from the cover (16); an outer wall (12) with overflow openings (14) which is covered by the ceiling (16) and which surrounds the outer row (20) of outer louvers (22);wherein the inner row (30) of inner louvers (32) is arranged closer to the inlet opening (18) than the outer row (20) of outer louvers (22); and the outer louvers (22) overlap with inner louver openings (38) formed between the inner louvers (32) such that the inner louver openings (38) are covered by the outer louvers (22) in the direction of the inlet opening (18).

2. Safety fitting (40) for an open tank (60) for receiving a liquid; comprising an inlet unit (10) connectable to an inlet for the liquid; a downwardly open dip tube (50) adjoining the inlet unit (10); wherein the inlet unit (10) comprises a cover (16) having an inlet opening (18) connectable to the inlet such that liquid flows from the inlet into the inlet unit (10); comprising an inner row (30) of inner louvers (32) spaced apart from one another and arranged around the inlet opening (18) and extending away from the cover (16); comprising an outer row (20) of outer louvers (22) spaced apart from the inner row (30), spaced apart from one another and arranged around the inlet opening (18) and extending away from the cover (16);an outer wall (12) with overflow openings (14) which is covered by the ceiling (16) and which surrounds the outer row (20) of outer louvers (22); wherein the inner row (30) of inner louvers (32) is arranged closer to the inlet opening (18) than the outer row (20) of outer louvers (22); and the outer louvers (22) and the inner louvers (32) are arranged such that they overlap from the direction of the inlet opening (18).

3. Inlet unit (10) or safety fitting (40) according to one of the preceding claims, characterized by the fact that the inner row (30) of inner slats (32) and the outer row (20) of outer slats (22) are arranged substantially on a closed curved track, preferably concentrically, and the outer wall (12) has substantially the form of a closed curved track, preferably arranged concentrically to the outer row (20) of outer slats (22).

4. Inlet unit (10) or safety fitting (40) according to the preceding claim, characterized by the fact that the distances between the inner slats (32) and / or the distances between the outer slats (22) are the same, preferably the distances between the inner slats (32) and between the outer slats (22) are the same.

5. Inlet unit (10) or safety fitting (40) according to one of the preceding claims, characterized by the fact that the inlet opening (18) is located in the center of the ceiling (16) of the inlet unit (10).

6. Inlet unit (10) or safety fitting (40) according to one of the preceding claims, characterized by the fact that the outer slats (22) and / or the inner slats (32) are each the same width and / or length.

7. Inlet unit (10) or safety fitting (40) according to one of the preceding claims, characterized by the fact thatthe inlet unit (10) comprises a lower bottom ring (24) which is connected to the outer wall (12) and the lower end of the outer lamellae (22).

8. Inlet unit (10) or safety fitting (40) according to one of the preceding claims, characterized by the fact that the sum of the widths of the overflow openings (14) is greater than the sum of the opening widths in the inner row (30) between adjacent inner slats (32) or than the sum of the opening widths in the outer row (20) between adjacent outer slats (22).

9. Inlet unit (10) or safety fitting (40) according to one of the preceding claims, characterized by the fact that the inlet opening (18) is dimensioned such that the flow velocity through the inlet is significantly less than 1 m 3 / h is, preferably less than 0.5 m 3 / h, preferably smaller than 0.1 m 3 / h, especially preferably smaller than 0.05 m 3 / h.

10. Inlet unit (10) or safety fitting (40) according to one of the preceding claims, characterized by the fact that The inner lamella opening (38) formed between two inner lamellae (32) has a height that is greater than a normatively specified overflow height.

11. Safety fitting (40) according to claims 2 and 3, characterized by the fact that the inlet unit (10) and the immersion tube (50) have a circular cross-section, wherein the diameter of the immersion tube (50) is smaller than the diameter of the outer wall (12) and larger than the diameter of the inner row (30) of the inner lamellae (32).

12. Open tank (60) for connection to a liquid network, with a safety fitting (40) according to claim 2, comprising an outlet arranged in the bottom (61) of the tank (60); a holding device for holding the safety fitting (40) on the tank (60) or an open housing of the tank (60).

13. Tank (60) according to the preceding claim, characterized by the fact thatthe volume of the tank (60) less than 1 m³ 3 is preferably smaller than 0.5 m 3 , preferably smaller than 0.1 m 3 , especially those smaller than 0.01 m 3 .

14. Tank (60) according to claim 12 or 13, characterized by the fact that the immersion tube (50) of the safety fitting (40) is designed such that it has a tube length that extends at least to a minimum operating fluid level, and that the free end is spaced away from the bottom (61) of the tank (60).

15. Device for connection to the drinking water network, comprising an open tank (60) for receiving water; a free inlet into the tank (60) by means of an inlet; and a safety fitting (40) according to claim 2, for preventing escape of supplied water during the inlet into the tank (60); wherein the dip tube (50), which is connected to the inlet unit (10), projects into the tank (60) such that the free end of the dip tube (50) is spaced apart from the bottom (61) of the tank (60).

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