TANK SYSTEM

Abstract

The invention relates to a tank system and a closure, comprising a base portion and a membrane portion, wherein the base portion has a jacket-shaped wall portion and a transition region adjacent thereto, wherein the membrane portion is adjacent to the transition region and protrudes from the transition region along a central axis, wherein the membrane portion is designed to be brought into a blocking state or into a passage state, wherein the membrane portion is substantially fluid-impermeable in the blocking state, and wherein the membrane portion is fluid-permeable along the central axis in the passage state.

Description

The present invention relates to a tank system, in particular for use in a motorhome or a caravan, and to a closure for use in such a tank system.

It is already known from the prior art that a tank, such as in particular a fresh water tank of a motorhome or a caravan, can have a ventilation and/or venting system in order to allow the air displaced by the introduced fluid to escape, as well as an overflow of excess fluid, when the tank is filled with fluid. Furthermore, it is known to allow ventilation of the tank, in particular to allow sufficient air to flow into the tank when a large amount of fluid is removed from the tank. For this purpose, in tank systems known from the prior art, so-called riser pipes which connect the interior of the tank to the surrounding environment are arranged and fixed in the tank. The problem here is that vermin or dirt particles can also get into the interior of the tank through these riser pipes, which severely impairs tank hygiene. In order to prevent such ingress of dirt particles or vermin, attempts have already been made to install a mechanical check valve in the riser pipe. However, this solution is, on the one hand, complex to construct and therefore costly, and, on the other hand, it is also susceptible to contamination, as dirt particles can seriously disrupt the function of the check valve.

It is therefore the object of the present invention to provide a tank system which is inexpensive and easy to produce and which ensures a high level of safety and tightness of the tank interior against the penetration of unwanted dirt particles and fluid.

These objects are achieved by a closure according to claim 1 and a tank system according to claim 10. Further embodiments and preferred features of the invention can be found in the dependent claims.

According to the invention, a closure is provided, in particular for use in a tank, comprising a base portion and a membrane portion, wherein the base portion has a jacket-shaped wall portion and a transition region adjacent thereto, wherein the membrane portion is adjacent to the transition region and protrudes from the transition region along a central axis, wherein the membrane portion is designed to be brought into a blocking state or into a passage state, wherein the membrane portion is substantially fluid-impermeable in the blocking state, and wherein the membrane portion is fluid-permeable along the central axis in the passage state. The closure is particularly intended and designed for use in or on a riser pipe of a tank system and has a base portion which has a jacket-shaped wall portion and a transition region. The wall portion is in particular designed with an outer surface adapted to the inner geometry of a riser pipe, such that the wall portion can be sealingly attached to the inner side of a riser pipe. In order to allow ventilation of the tank interior despite the sealing arrangement of the closure in the riser pipe, the closure has a membrane portion which is designed in such a way that it normally assumes a blocking state and can only be brought into a passage state when a pressure difference is applied in a selected direction, in which passage state a fluid, preferably a gas, air or water, can flow through the closure in order to get from the tank interior to the outside. Put simply, the membrane portion of the closure acts as a one-way valve, which only allows fluid exchange in one flow direction. Between the base portion which can be arranged in a sealing manner in the riser pipe and the membrane portion, a transition portion is provided which in particular connects the different external geometries of the base portion and the membrane portion. The central axis is preferably an axis running centrally through the base portion, the transition portion and the membrane portion, which axis is preferably simultaneously the axis along which a fluid flow can flow through the membrane portion. Preferably, when the closure is inserted into a riser pipe, the central axis is coaxial with the pipe axis of the riser pipe in the region of the closure.

In one embodiment, the wall portion is designed to be substantially axially symmetrical and/or rotationally symmetrical about the central axis and preferably has a circular cross section. A substantially axially symmetrical and/or rotationally symmetrical cross-sectional geometry is understood to mean, in particular, a square or circular outer shape of the wall portion. It is understood within the scope of the present invention that the wall portion is adapted to the internal geometry of the riser pipe in order to form a sealing connection there. Preferably, the wall portion is overdimensioned compared to the inner geometry of the riser pipe, such that the closure can be clamped in the riser pipe under elastic prestress. This ensures, on the one hand, a fixed arrangement of the closure in the riser pipe and, on the other hand, a high level of tightness in the edge region of the closure.

In one embodiment, the transition portion has, in a cutting plane running parallel to the central axis, a substantially V-shaped cross section which tapers toward the membrane portion. The V-shaped geometry of the transition portion in cross section is particularly material-saving and connects the axially symmetrical or rotationally symmetrical wall portion to the substantially flat membrane portion. At the same time, the V-shaped transition portion ensures that if fluid collects in the base portion, it can flow reliably toward the membrane portion, provided that there is a corresponding overpressure in the tank.

In one embodiment, at least the membrane portion is formed from an elastically deformable material having a Shore hardness of 20 to 90 Shore A, preferably 50 to 70 Shore A. LSR (liquid silicone rubber) is particularly preferably used as the production material for at least the membrane portion. The very low Shore hardness of this material allows particularly easy elastic deformation of the membrane portion. Alternatively or additionally, this good deformability is also achieved by low wall thicknesses in the region of the membrane portion. In this way, the membrane portion can be brought into its passage state with only a relatively low overpressure in the tank. In addition, LSR has very good permanent elasticity and is approved for drinking water systems. Particularly preferably, the entire closure, i.e., all regions such as the base portion and the membrane portion or a preferably present collar, is formed in one piece from the same production material. In an alternative embodiment, the membrane portion can be formed from a softer material than the base portion and the transition portion by means of a coextrusion process or two-component casting process.

In one embodiment, the membrane portion has a first membrane wall and a second membrane wall opposite the first membrane wall, wherein the first and the second membrane walls in the blocking state lie against each other substantially over their entire surface, and wherein in the passage state a gap is formed between the first membrane wall and the second membrane wall and is fluid-permeable along or parallel to the central axis. The membrane walls are two flat, flap-like regions of the membrane portion which are preferably connected to each other at their respective lateral ends by common corner regions. In other words, the membrane walls together with the two corner regions define a flat tube. The membrane portion is shaped in such a way that the membrane walls lie flat against each other, wherein the length of the membrane walls parallel to the central axis ensures that a fluid flowing through in the direction of the base portion is reliably prevented.

In one embodiment, the membrane portion has, at least in the blocking state, a substantially flat and planar extent parallel to a gap plane, wherein the central axis lies in the gap plane. The flat base state of the membrane portion allows a particularly large contact area between the membrane walls, which allows reliable sealing, in particular in the case that the pressure at the distal end pointing away from the base portion is greater than in the base portion. In this case, the membrane walls are pressed together by the external pressure and a higher tightness of the membrane portion is created, which increases the blocking state.

In one embodiment, the base portion is pot-shaped and open at its end facing away from the transition region. The pot-shaped design of the base portion allows splash water to collect in the upper region of the closure, but even when there is only a slight overpressure in the tank, it can flow out of the tank interior via the membrane portion. At the same time, fluid standing in the base portion serves to further seal against the penetration of gas, which may contain harmful aerosols.

In one embodiment, an overpressure in the main body compared to the pressure at a distal end of the membrane portion puts the membrane portion into the passage state such that a fluid can flow from the base portion toward the distal end, wherein the overpressure is preferably in the range from 50 Pa to 600 Pa, particularly preferably from 90 Pa to 400 Pa. The particularly easily deformable elastic material of the membrane portion is designed so that even a slight overpressure in the tank compared to the environment ensures that the membrane portion reaches the passage state. This allows excess air (when filling the tank) or liquid (when overfilling the tank) to reliably escape through the closure into the riser pipe. The initially particularly broad range of 50-600 Pa preferably covers all operating conditions present in motorhomes and caravans. The range of 90-400 Pa has proven particularly suitable for use in motorhomes which are mainly used in Europe and at altitudes of up to 2000 m above sea level.

In one embodiment, the base portion has a collar which has a greater extent orthogonal to the central axis than the wall portion. The collar is preferably a concealed region at the upper edge of the base portion. On the one hand, the collar is designed to be placed on the blunt end of a riser pipe and brought into contact there. In a particularly preferred embodiment, the collar is intended to be slipped over the blunt end of a riser pipe, such that the base portion on the inner side and the collar on the outer side of the end of the riser pipe enclose it and thus form a particularly firm and sealed connection with the riser pipe. Particularly preferably, the collar is formed together with the base portion as part of a one-piece closure.

In one embodiment, the membrane portion has a maximum membrane length measured parallel to the central axis, wherein the membrane portion has a maximum membrane width measured orthogonal to the central axis, wherein the membrane length is in a ratio of preferably 0.7 to 2, particularly preferably 0.9 to 1.5 to the membrane width. It has been shown that the best compromise between sufficient sealing and simultaneous material savings can be achieved when a length of the membrane walls along the central axis is approximately equal their width orthogonal to the central axis. The longer the membrane length relative to the membrane width, the longer the path over which sealing can occur in the membrane portion. At the same time, assembly is easier and material savings are improved if the membrane length is approximately the same or slightly smaller than the membrane width. It is understood that the membrane width can also be designed to be significantly smaller than the internal width available in the riser pipe, in particular in order to provide a smaller passage region in the membrane portion and to establish a higher seal and optionally a higher pressure difference until fluid escapes from the tank.

In one embodiment, the membrane length is in a ratio of 0.2 to 0.7 and preferably 0.3 to 0.6 to a total length of the closure measured parallel to the central axis. The membrane length in relation to the total length of the closure along the central axis is thus an expression of how high the proportion of the membrane is in comparison to the base portion, in particular to the wall portion of the base portion. In particular, in the case where a smooth riser pipe requires only a short length of the wall portion parallel to the central axis, the membrane portion can take up a higher proportion of the length of the closure. The particularly preferred range of 0.3 to 0.6 has proven to be the most favorable compromise between a sufficient sealing length in the wall portion and a sufficient membrane length to achieve a reliable blocking state in the membrane portion.

In one embodiment, the base portion has a maximum diameter measured orthogonal to the central axis, wherein the membrane width is in a ratio of 0.5 to 0.95, preferably 0.7 to 0.8, to this maximum diameter. Alternatively or additionally, the diameter is in a ratio of 0.2 to 0.7, preferably 0.3 to 0.5, to a total length of the closure measured parallel to the central axis. The ratio of the membrane width to the diameter of the base portion shows in particular which width the membrane takes up in comparison to the usually available internal width of a riser pipe. A particularly wide membrane portion can achieve a large passage opening in the passage state, which simplifies the overflow of excess air or fluid from the tank. Alternatively, it may be preferred that only a small passage opening is provided by a particularly narrow membrane, thereby increasing the sealing effect of the closure. In the case of a rectangular or square cross section of the base portion, the maximum diameter is defined as the largest diagonal which can be drawn through the base portion perpendicular to the central axis. In the simpler case of a substantially circular cross-sectional geometry of the base portion, the diameter is corresponding to the circle diameter of the outermost outer surface of the base portion. In the event that the base portion has a collar, the maximum diameter of the base portion is preferably in the region of the collar. In case the base portion does not have a collar, the maximum diameter must be measured in the region of the wall portion. The ratio of the largest diameter of the closure in the base portion to the total length of the closure is an expression of the particularly proven design and scaling of closures for use in differently dimensioned riser pipes. The particularly preferred range of 0.7-0.8 is a special embodiment for use in standardized riser pipes in tanks of motorhomes.

In one embodiment, the first and the second membrane walls extend, at least in the blocking state, substantially parallel to a gap plane, wherein at least one, preferably both, of the membrane walls has a wall thickness, measured orthogonal to the gap plane, which is 0.75% to 5%, preferably 1% to 2%, of a greatest length of extent of the respective membrane wall orthogonal to the pipe axis. The particularly small wall thickness of the membrane walls allows for easy deformation of the membrane walls. Thus, the membrane portion reacts particularly sensitively and immediately to pressure changes and can allow for improved sealing or easy venting of the tank.

According to the invention, a tank system is further provided, comprising a tank and a riser pipe which extends at least partially inside the tank, wherein a closure with the features described above is fixed in or at a first end region of the riser pipe, such that the riser pipe is sealed by the closure, wherein the riser pipe opens into the environment at a second end region. In addition to the usual tank known from the prior art, the tank system comprises a basically known riser pipe, which, however, does not have a pressure relief valve or an unsealed opening at its distal end region located inside the tank, but is equipped with a closure according to the above description. The closure is preferably arranged only at a distance of 2 mm to 3 cm below the inner wall of the tank, which allows for a particularly long riser pipe. In addition, this minimizes the sloshing of liquid into the closure, in particular while the motorhome or caravan is moving. In the embodiment in which only one closure allows flow in one direction, in particular the direction leading out of the tank into the riser pipe and into the environment, the closure is designed to function as a one-way valve.

In one embodiment of the tank system, a T-piece is provided at the first end region, wherein a first closure is arranged in a first outlet of the T-piece such that the membrane portion of the first closure extends in the direction of the riser pipe, and wherein a second closure is arranged in a second outlet of the T-piece such that the membrane portion of the second closure points away from the riser pipe. The T-piece can be designed as a separate pipe section that can be placed on the distal end of a riser pipe. Alternatively, the T-piece is preferably designed as an integral and one-piece component of a riser pipe. A closure can thus be arranged in each of the two open end portions of the T-piece arranged inside the tank, wherein a first closure allows flow into the tank and a second closure allows flow out of the tank. Flow into the tank is preferred in order to prevent the development of a negative pressure and thus a pressure drop in the corresponding pipe systems of the motorhome or caravan in the event of a large amount of liquid being removed from the tank by allowing sufficient amounts of air to flow into the tank. The decisive factor here is that for this inflow to occur, a certain, previously described minimum pressure differential must be present across the closure and otherwise the closure is in the blocking state, which generally prevents fluid and thus also foreign bodies from flowing into the tank.

Further advantages and features of the present invention will become apparent from the following description of selected exemplary embodiments with reference to the accompanying figures. It is understood that individual features shown only in certain embodiments can and should also be used in other embodiments, unless this is prohibited due to technical circumstances or explicit mention.

The figures show the following:

FIG. 1—a view of an embodiment of a closure;

FIGS. 2 and 3—two sectional views of the embodiment shown in FIG. 1;

FIGS. 4 and 5—two embodiments of riser pipes with closures arranged therein;

FIG. 6—a schematic view of an embodiment of a closure; and

FIG. 7—a view of a tank system.

The closure 4 shown in FIG. 1 is shown in a side view in which the gap plane S is perpendicular to the viewing plane. At the same time, the central axis M in this view lies in the gap plane S. The closure 4 has a base portion 5, which in this embodiment has a wall portion 52, a transition portion 54 and a collar 56. In the region between the collar 56 and the wall portion 52, a transition region tapering substantially in the shape of a truncated cone is provided. With this transition region, the closure 4 can be placed on the blunt end of a riser pipe 10, wherein the collar 56 is then slipped over this open end of the riser pipe 10. As an alternative to slipping it over, the closure 4 can also be supported in this region on the open end of the riser pipe 10. The wall portion 54 is intended to be installed on the inside of the riser pipe 10 and in this embodiment has a cylindrical outer geometry. The membrane portion 6 extends downward substantially parallel to the central axis M and, in this embodiment, also parallel to the gap plane S. Between the membrane portion 6 and the wall portion 52 of the base portion 5, a transition portion 54 is provided which has a substantially V-shaped cross section. The membrane portion 6 has a membrane length 65 between its connection to the transition portion 54 and its lower, distal end 67, which in this embodiment is slightly smaller than half the total extent of the closure 4 parallel to the central axis M.

FIG. 2 shows the sectional view indicated in FIG. 1 in the region of the wall portion 52 of the main body 5. The position of the membrane portion 6 can be seen here, which extends centrally and on the underside of the transition portion 54 substantially parallel to the gap plane S. The central axis M is advantageously located in the circle center of the cylindrical outer geometry of the wall portion 52. FIG. 2 schematically shows the blocking state Z of the membrane portion 6, in which the membrane walls 61, 62 lie directly against one another.

FIG. 3 shows the detailed view indicated in FIG. 2. It can be seen that the membrane portion 6 preferably has a first membrane wall 61 and a second membrane wall 62, which extend substantially parallel to one another and parallel to the gap plane S. FIG. 3 shows the passage state A, in which a gap 68 is formed between the membrane walls 61, 62 through which a fluid can flow. At their respective end regions, the first membrane wall 61 and the second membrane wall 62 are each connected to one another by a corner region 63. The membrane portion 6 thus forms a flat, tubular portion which is closed in its base state such that the membrane walls 61, 62 lie against one another, thus creating the blocking state Z of the membrane portion 6. Only in the passage state A, which can be achieved by means of an overpressure in the main body 5, are the membrane walls 61, 62 spaced apart from one another in such a way that a gap 68 is formed through which fluid can pass. The wall thickness w of the membrane walls measured orthogonally to the gap plane S is preferably approximately 1% to 2% of a maximum length of extent of the corresponding membrane wall 61, 62 orthogonal to the tube axis R, i.e., the membrane width 66.

FIG. 4 shows a first embodiment of a riser pipe 10 with a first end region 11 arranged at the top and a second end region 12 arranged at the bottom. Adjacent to the second end region 12, the riser pipe is screwed to the lower wall of a tank 2 (see FIG. 7) and is open to the environment. At its first end region 11, the riser pipe 10 is closed by a closure 4 according to any one of the embodiments of FIG. 1-3. In this embodiment, the closure 4 is inserted into the riser pipe 10. The pipe axis R of the riser pipe 10 runs substantially collinear to the central axis M of the closure 4.

FIG. 5 shows a further embodiment of a riser pipe 10, in which, in contrast to FIG. 4, a T-piece 14 is attached to the first end region 11 of the riser pipe 10. In this T-piece, two closures 4 are inserted, which close the T-piece 14 and thus the first end region 11 of the riser pipe 10. One of the closures 4 is arranged such that its membrane portion 6 extends into the T-piece 14, thus allowing a flow from the tank interior into the riser pipe 10. The second closure 4 is inserted into the T-piece 14 in such a way that its membrane portion 6 extends away from the T-piece 14. This closure 4 thus allows an inflow from the riser pipe 10 into the tank interior.

The schematic view of FIG. 6 shows the geometry of a preferred embodiment of a closure 4, wherein the maximum outer diameter D is set in relation to the membrane width 66. In this embodiment, the base portion 5 preferably does not have a collar 56 and the wall portion 52 is thus the region in which the largest outer diameter D of the base portion 5 is present.

Lastly, FIG. 7 shows an embodiment of a tank 2 of a tank system according to the present invention. A riser pipe 10 is arranged in this tank 2, which riser pipe is open to the environment at its lower, second end region 12 and is closed by a closure 4 at its upper, first end region 11 arranged within the tank 2.

LIST OF REFERENCE SIGNS

• • 2—Tank
  • 4—Closure
  • 5—Base portion
  • 6—Membrane portion
  • 10—Riser pipe
  • 11—First end region
  • 12—Second end region
  • 14—T—piece
  • 52—Wall portion
  • 54—Transition region
  • 56—Collar
  • 61 First membrane wall
  • 62—Second membrane wall
  • 63—Corner region
  • 65—Membrane length
  • 66—Membrane width
  • 67—Distal end
  • 68—Gap
  • A—Passage state
  • D—Diameter
  • M—Central axis
  • R—Pipe axis
  • S—Gap plane
  • w—Wall thickness
  • Z—Blocking state

Claims

1. Closure, in particular for use in a tank, comprising a base portion and a membrane portion,wherein the base portion has a jacket-shaped wall portion and a transition region adjacent thereto,wherein the membrane portion is adjacent to the transition region and protrudes from the transition region along a central axis,wherein the membrane portion is designed to be brought into a blocking state or into a passage state,wherein the membrane portion is substantially fluid-impermeable in the blocking state, andwherein the membrane portion is fluid-permeable along the central axis in the passage state.

2. Closure according to claim 1, wherein the wall portion is substantially axially symmetrical and/or rotationally symmetrical about the central axis and preferably has a circular cross section.

3. Closure according to claim 1, wherein at least the membrane portion is formed from an elastically deformable material having a Shore hardness of 20 to 90 Shore A, preferably 50 to 70 Shore A.

4. Closure according to claim 1, wherein the membrane portion has a first membrane wall and a second membrane wall opposite the first membrane wall,wherein the first and second membrane walls in the blocking state lie against each other substantially over their entire surface, andwherein in the passage state a gap is formed between the first membrane wall and the second membrane wall and is fluid-permeable along or parallel to the central axis.

5. Closure according to claim 1, wherein the membrane portion, at least in the blocking state, has a substantially flat and planar extent parallel to a gap plane, wherein the central axis lies in the gap plane.

6. Closure according to claim 1, wherein the base portion is pot-shaped and is open at its end facing away from the transition region.

7. Closure according to claim 1, wherein an overpressure in the main body compared to the pressure at a distal end of the membrane portion puts the membrane portion into the passage state such that a fluid can flow from the base portion toward the distal end,wherein the overpressure is preferably in the range from 50 Pa to 600 Pa, particularly preferably from 90 Pa to 400 Pa.

8. Closure according to claim 1, wherein the base portion has a collar which has a greater extent orthogonal to the central axis than the wall portion.

9. Closure according to claim 1, wherein the membrane portion has a maximum membrane length measured parallel to the central axis,wherein the membrane portion has a maximum membrane width measured orthogonal to the central axis,wherein the membrane length is in a ratio of preferably 0.7 to 2, particularly preferably 0.9 to 1.5 to the membrane width.

10. Tank system, in particular tank system of a motorhome or caravan, comprising a tank and a riser pipe which extends at least partially inside the tank, wherein in or at a first end region of the riser pipe a closure according to claim 1 is fixed, such that the riser pipe is sealed by the closure, wherein the riser pipe opens into the environment at a second end region.