DE102012219530A1 - Membrane and container arrangement - Google Patents

Abstract

Membrane of a container, in particular of a pressure expansion vessel, wherein the membrane can be arranged inside a container and has a working area which is designed for displacement in the container, wherein a pressure ratio can be applied to the membrane in the container, the working area at least partially consisting of a first material is formed, which behaves essentially rigidly in the pressure ratio, and wherein the working area has at least one elastic area which behaves elastically in the pressure ratio, whereby the working area within the container, preferably by the pressure ratio, is displaceable.

Description

The present invention relates to a membrane, in particular a pressure expansion vessel, and a container arrangement, which is designed in particular as a pressure expansion vessel.

Expansion tanks or surge tank of the type in question are well known in the art. Thus, such surge tanks are designed as components in hydraulic systems that absorb the change in volume of the hydraulic fluid between minimum and maximum temperature and thus should keep the pressure largely constant. Frequently, such expansion tanks are used in heating systems and domestic water, cold water, solar and hydraulic circuits. Such expansion tank have a flexible membrane, in particular a rubber membrane, which separates the liquid and the gas storage within a container usually formed by two container halves. The materials used for the rubber membrane are usually expensive, poorly available and difficult to process. Furthermore, in order to ensure a low permeation, such rubber membranes must be manufactured with a corresponding wall thickness. However, this increases the material costs and reduces the flexibility of the membrane. Further, at higher temperatures, the durability of the membrane and its increasing permeability pose challenges.

It is therefore an object of the present invention to provide a membrane of a container and a container arrangement, in particular a pressure expansion vessel, which have a high durability at the same time highest flexibility and a low permeability at low material costs.

This object is achieved by a membrane of a container according to claim 1 and by a container assembly according to claim 10. Further advantages and features of the invention will become apparent from the subclaims and the description and the accompanying figures.

According to the invention a membrane of a container, in particular a pressure expansion vessel, is provided, wherein the membrane can be arranged within a container, and having a working area, which is designed for a displacement in the container, wherein in the container, a pressure ratio on the membrane can be applied, the working area is at least partially formed from a first material which is substantially rigid at the pressure ratio, and wherein the working area has at least one elastic region which behaves elastically at the pressure ratio, whereby the working area within the vessel, preferably by the pressure ratio , is relocatable. Such containers or pressure expansion vessels are advantageously used in heating systems and industrial water, cold water, solar and hydraulic circuits, etc., to compensate for volume changes of a fluid. The membrane preferably divides the container into a fluid space and a gas reservoir or gas space. The fluid or the liquid is preferably water, which may preferably be provided with heating additives also with corresponding heating additives. The fluid space, hereinafter referred to as water space, is connected to the water cycle, for example, the heating system. The gas space is provided with a system-conditioned form. When the temperature in the system rises, the resulting expansion water presses against the gas pressure in the container. During cooling and the associated reduction in volume, the gas pressure acting on the membrane ensures that the expansion water is returned to the system. The pressure ratio thus results in the rule between the pressure in the water space, which is preferably connected to the water cycle of the heating system, and the pressure in the gas space, which preferably via a valve, in particular a lockable cap valve, which is arranged on the container with a Form is acted upon. Characterized in that the membrane comprises the working area, which has an at least partially elastic region, the working area, depending on the pressure ratio is adjusting, displaced. Advantageously, this function separation takes place, since the work area is at least partially formed of a first material, which behaves substantially rigid in the pressure ratio. The first material therefore does not allow any displacement on its own, since it is essentially not deformable in the applied pressure conditions. Advantageously, however, the first material is a material, which is characterized by a very high durability, the lowest permeability and the lowest cost. Thus it is an important goal to prevent a diffusion of substances from the gas space into the fluid space and vice versa. As a rule, the gas in the gas space is nitrogen. If the working area, which is exposed to direct contact with the gas space, has a high permeability, the set admission pressure in the gas space would drop considerably over time and the system functionality would no longer be guaranteed. Nitrogen would diffuse from the gas space into the water space. It is understood that conversely, the permeation of H ₂ O must be prevented by the membrane. Advantageously, the first material prevents the diffusion of substances from the gas space into the fluid space and vice versa. Nevertheless, in order to provide the displaceability of the membrane or of the working area as a whole, it is at least an elastic one Area provided. The working region of the membrane formed from the first material is thus mounted, so to speak, movably over the at least one elastic region within the container. The first material expediently has a lower gas and / or fluid / liquid permeability than the elastic region. Conversely, the elastic region is more elastic than the first material. Preferably, values of flexural strength and / or tensile strength of the first material are higher than those of the elastic region. Advantageously, the permeability of the first material does not change or only slightly with increasing temperature. Thus, the permeability does not increase as the temperature in the container increases. Underlying temperature ranges are in a range of about 50 to 70 ° C and higher. Advantageously, a consistent function of the membrane over the entire life of the container is possible.

Advantageously, the work area comprises the first material substantially in a central region of the membrane which extends substantially parallel to a membrane plane, wherein the at least one elastic region is arranged around the central region. The named form corresponds in an ideal way with the common or known forms of such containers or pressure expansion vessels. These generally have a cylindrical and / or rectangular shape, wherein the membrane is arranged in a round cross-section of the container, which results from the cylindrical shape. Preferably, therefore, the membrane is substantially round or more preferably approximately circular. The membrane plane, which extends substantially parallel to the membrane or vice versa, is therefore advantageously perpendicular to a longitudinal axis of the container or parallel to the cross section of the container. This results in the particularly preferred embodiment of a membrane with the working area, which is formed in the middle region of the first material, wherein the at least one elastic region is arranged around the central region. Preferably, the central region is approximately round or preferably also substantially circular in shape and, so to speak, annularly surrounded by the elastic region. In other words, so to speak, the elastic region provides a flexible interface or a soft bearing between the (rigid) central region formed from the first material and the usually of a metal, for. As a result of the fact that the interface is designed to be movable in the form of the elastic region, the rigid middle region is displaceable relative to the rigid container. The volume fluctuations of the fluid or water can thus be compensated in an ideal manner, although the working range of the membrane is formed of the first material, which behaves rigidly under the prevailing pressure conditions. It is understood that the central region formed from the first material need not be circular.

Advantageously, the work area is formed radially from a center of the membrane at least partially either from the first material or from the elastic region. Advantageously, the center of the membrane lies on an axis of the substantially cylindrical container. In the middle region or starting from the center now extends the first material. Advantageously, only the first material is provided in this area. In a preferred embodiment, the first material extends to a first radius. Between the first radius and a second radius, starting from the center, then extends exclusively annularly the elastic region. Preferably, a ratio of the first to the second radius in a range of about 0.3 to 0.95, more preferably in a range of about 0.4 to 0.9 or about 0.5 to 0.85. It can be stated here that, in principle, the working region formed from the first material is preferably formed flat as a substantially flat disc. Alternatively, other embodiments are conceivable, for example, a wavy or zigzag-shaped configuration or a spherical shape, in particular a substantially hemispherical design and / or a dome shape. In this case, the waveform or the zigzag shape and / or an angular shape extend substantially concentrically starting from the center. The transition from the first material to the elastic region can advantageously be continuous and / or stepped. As a preferred joining method at this point an adhesive method is given, via which the elastic region is joined to the first material. In this case, a shock can be formed, as mentioned, but also a stepless transition possible. Alternatively, an encapsulation and / or encapsulation or casting and / or injection of the elastic region on or on the first material is preferred. Advantageously, during encapsulation, encapsulation, injection molding or casting, a direct adhesion of the soft components to the hard components, in other words the elastic region on the first material, is possible. Preferably, therefore, the first material and the elastic region are coordinated with respect to the adhesion. Also preferred is the use of suitable adhesives which improve the adhesion of the first material to the elastic region. Expediently, the working region is also formed radially from the center of the membrane and also partially only from the elastic region. Such embodiments are preferably of interest when the first Material formed work area with soft components z. B. is injected. In a preferred embodiment, the work area formed from the first material is a plastic molded part, in particular with a ribbing. The molded part formed from the first material is preferably encapsulated with a soft material, which forms or forms the flexible region. The encapsulation takes place in such a way that the working area in a cross section parallel to the membrane plane partially consists of the first material and the elastic region. At the same time sections are also provided in the work area, in which only the elastic region is present transversely to the membrane plane. A work area formed from the first material can advantageously also have an extension transverse to the membrane plane. The extension can be advantageously designed in the form of ribs, profiles or webs, etc. Further, undercut, openings, slots and the like may be provided. The focus here is not only that such trained and formed from the first material work areas have only good rigidity, they should also work well with other materials, eg. As elastomers, can be encapsulated.

Further preferably, the working area in a cross section substantially perpendicular to the membrane plane at least partially the elastic region and the first material. In other words, therefore, a layer structure is also preferred which, as it were, provides a sequence of the elastic region and the first material. In order to provide sufficient flexibility, the layer structure is only partially provided. In a preferred embodiment, a substantially round central region formed from the first material, above and below, ie substantially transversely to the membrane plane, is surrounded by the elastic region. Since the first material is provided only in the middle region, the elastic region is still preferably provided annularly around the rigidly formed central region. In other words, the first material is embedded in the elastic region, so to speak. In this case, the arrangement can also be such that only one surface of the rigidly formed working area is provided with the elastic region. Preferably, the first material and the elastic region can be glued together. Alternatively preferably, the first material can also be encapsulated and / or cast on by the elastic region.

Advantageously, a thickness of the first material that measures substantially in a direction transverse to the membrane is at a maximum extension of the elastic range in that direction in a ratio of 0.001 to 0.5, more preferably in a range of about 0, 0015 to 0.4 or about 0.002 to 0.3. Also preferably, a ratio greater than about 0.5 or greater than about 1, after which the first material is then formed thicker in relation to the elastic region. Thus, the area is addressed in which the first material and the elastic region are provided transversely to the membrane or to the membrane plane. If there are several "layers" of first material and elastic regions, so to speak, the thicknesses of the individual layers are added together to calculate the ratio. Preferably, the ratio is to be selected such that the best possible compromise between lowest permeability and maximum flexibility is guaranteed. The fact that the first material has such a low permeability, the thickness can be reduced compared to the prior art, whereby more cost-effective membranes are manufacturable. Alternatively, with a same thickness of the membrane as known from the prior art, an extremely low permeability and thus freedom from maintenance can be achieved.

Preferably, an attachment portion is formed in an edge region of the membrane, via which the membrane can be arranged between and / or on two container halves, wherein the edge region is the at least one elastic region. Preferably, the addressed, substantially cylindrical, container are constructed from two substantially cylindrical container halves. The arrangement of the membrane between the container halves is preferably carried out positively and / or non-positively. Alternatively preferably, a cohesive connection is conceivable. In a preferred embodiment, the attachment portion is formed as a bead-starting ring.

Preferably, the attachment portion has at least one reinforcing element, preferably a plastic and / or a metal ring. The reinforcing element is preferably also formed substantially circumferentially within the attachment portion. A cross section of the reinforcing element is preferably substantially round or circular. Alternatively preferred also angular cross-sectional shapes are used. Further preferably, a plurality of, for example, two, three, four or more reinforcing elements within the mounting portion can be arranged. Likewise preferred is also an arrangeability not within the attachment portion but at the attachment portion.

Advantageously, the first material has a lower permeability than a second material, wherein the elastic region is formed from the second material. The material used in the prior art for the membrane is usually IIR (isobutene-isoprene rubber, butyl rubber), which expensive, poorly available and difficult to process. Furthermore, the permeation of IIR increases with increased temperature. This has the consequence that the nitrogen cushion must be renewed after a defined time and the system is not maintenance-free. Advantageously, the first material is a metal sheet or PA (polyamide) or PET or PBT (polyethylene terephthalate / polybutylene terephthalate). The first material thus preferably has a higher tensile strength and / or flexural strength than the second material. Furthermore, the first material has a lower permeability (gas and / or fluid / liquid permeability) than the second material. In addition, the permeability is constant over different temperature ranges. Thus, in the underlying temperature ranges prevailing in the container, at about 50 to 70 ° C and higher, the permeability of the first material does not increase as the temperature increases (or decreases). The permeability is advantageously constant or approximately constant in the temperature ranges prevailing in the mentioned fields of application. Alternatively, a combination of materials from the aforementioned materials is conceivable. The materials mentioned for the first material show a much lower permeability than z. B. IIR. The second material is preferably an elastomer or a flexible material. A material combination of elastomer / elastomer is conceivable. Thus, the first material may also be an elastomer, for example an elastomer which has a higher flexural rigidity, tensile strength and permeability than the second material, which is also an elastomer. Decisive is advantageously the separation of functions, namely to provide an elastic region which allows the displacement of the work area per se (by its elasticity) and to make a portion of the working area so that it has a very low permeability or a lower permeability than the elastic region or the second material, for. B. IIR has.

Preferably, without concern of the pressure ratio, the ratio of an area of the first material to an area of the elastic range is in a range of about 0.001 to 0.7, more preferably in a range of about 0.002 to 0.65, or about 0.003 to 0.6 , The term surface means the surfaces of the region formed from the first material and the elastic region which form substantially parallel to the membrane plane. This also includes the possibly covered by the second material portions of the first material. The above-mentioned ribs, undercuts and the like are not to be counted. If the work area formed from the first material and / or the elastic area in an unloaded state have shapes that do not extend at least partially parallel to the membrane plane (for example due to a curved or wavy shape), these are areas for calculating the ratios assume the surfaces projected vertically on the membrane plane.

According to the invention, a container arrangement, in particular a pressure expansion vessel, a container and a membrane of a first material, wherein the membrane has a working area, which is designed for a displacement in the container, wherein in the container, a pressure ratio on the membrane can be applied, wherein the Workspace is formed of a first material which is substantially rigid at a pressure ratio, wherein the working area has at least one elastic region which behaves elastically at the pressure ratio, whereby the working area within the container, preferably by the pressure ratio, is displaced.

In a further preferred embodiment, a ratio of a maximum thickness of the second material in a region which has exclusively the second material essentially transversely to the membrane plane, lies at a maximum extension of the membrane parallel to the membrane plane in a ratio of approximately 0.00001 to 0, 05, more preferably in a range of about 0.0001 to 0.002, or about 0.0005 to 0.001. The maximum thickness is measured essentially transversely to the membrane plane. If the region of the second material is not parallel to the membrane plane, the maximum thickness of the second material is calculated substantially perpendicular to the surface of the corresponding region.

Advantageously, at least one further element is arranged on the membrane. The further element may be a subsequently applied foil or subsequently applied foils, which may further reduce the permeability. Also, paints or the like are attachable to reduce the permeability. Advantageously, the first material is suitable because of its rigidity that more elements can be attached. This would not be possible if the first material were not dimensionally stable when moving the work area.

Further advantages and features will become apparent from the following description of preferred embodiments of the membrane of a container according to the invention and the container assembly with reference to the accompanying figures. Individual features of the individual embodiments can be combined with each other within the scope of the invention.

Show it:

1 a preferred embodiment of a membrane of a container in a sectional view arranged between two container halves;

2 a preferred embodiment of a membrane of a container in two displacement states;

3 : A preferred embodiment of a membrane in a plan view.

1 shows a preferred embodiment of a membrane 20 with a workspace 22 which is between a fluid space 66 and a gas room 64 is arranged. Between the fluid space 66 and the gas space 64 a pressure ratio Δp is established. The workspace 22 points in its middle area 26 a first material 40 on. The membrane 20 or the workspace 22 is aligned substantially parallel to a membrane plane E. A center of the membrane is through a center 27 marked. The middle area 26 is bordered by a border area 28 which is in 1 an elastic area 44 represents and in the preferred embodiment of a second material 42 consists. The border area 28 ends in a mounting section 24 , The attachment section 24 is in the in 1 illustrated embodiment as a separate substantially annular member, for example made of metal, which on the one hand cohesively with the elastic region 44 , on the other hand cohesively with the container halves 62 connected is. The cohesive connection of the fastener 24 with the container halves 62 or with the container 60 takes place in the present embodiment preferably via a welded connection. Essentially transversely to the membrane plane E, the membrane 20 a thickness d on. Starting from the midpoint 27 the first material extends in a radius r1. Up to one edge of the membrane 20 extends from the center 27 a diameter r2. In the illustrated preferred embodiment, the radii r 2 and r 1 result in the substantially annular configuration of the elastic region 44 ,

2 shows a preferred embodiment of a container assembly in a sectional view in two different states of displacement of a membrane 20 , A container 60 is through two container halves 62 connected. The upper half of the container 62 has a port (not numbered) on what water into a fluid space 66 can be introduced. The fluid space 66 is through the membrane 20 or a workspace 22 from a gas room 64 separated. In the left half of the container or a container is shown a state in which in the fluid space 66 one compared to the gas space 64 low pressure prevails. A pressure ratio Δp is thus designed so that the membrane 20 or the workspace 22 from the gas space 64 in the direction of the fluid space 66 is relocated. A pressure in the gas space 64 is therefore higher than a pressure in the fluid space 66 , 2 , shows clearly that only one edge area 28 which has an elastic range 44 represents, is deformed. In the right half of the picture or container, on the other hand, a state is shown in which in the fluid space 66 one opposite the gas space 64 high pressure prevails. The resulting pressure ratio Δp causes the membrane 20 or the workspace 22 from the fluid space 66 in the direction of the gas space 64 is shifted towards. The workspace 22 exists in a middle area 26 from a first material 40 , The border area 28 is, as mentioned, as the elastic region 44 educated. 2 shows a substantially flat formed central region 26 , Alternatively, the middle region is preferred 26 z. B. formed substantially hemispherical and / or dome-shaped. In the preferred embodiment, the elastic region exists 44 from the second material 42 , The border area 28 further includes a in the preferred embodiment bead-shaped attachment portion 24 on, which also from the second material 42 is formed. In the left half of the picture is a reinforcing element 80 within the attachment section 24 arranged, which has a round or circular cross-section substantially. The reinforcing element is preferred 80 formed as at least partially running ring of a hard material or hard components such as a plastic and / or metal ring. In the right half of the figure is an alternative preferred embodiment of the reinforcing element 80 shown. The shape is similar to that in the left half of the picture, but here are preferably three smaller reinforcing elements 80 arranged. The lower half of the container 62 shows sketchy a valve (without reference numeral), via which the gas pressure in the gas space 64 is adjustable. The two container halves 62 which the container 60 are in the margins 28 or in the attachment section 24 the membrane 20 positively and / or non-positively connected via a kind of clip (without reference numeral). Advantageously, this attachment is applicable via at least one clip, since by the reinforcing elements 80 which the attachment section 24 Support from inside as it were, this can be clamped from the outside. An excellent sealing effect is the result.

3 shows a preferred embodiment of a membrane 20 in a top view. You can see a substantially circular shape of the membrane 20 , The membrane 20 indicates the known division of a workspace 22 in a middle area 26 and a border area 28 on. The middle area 26 includes a midpoint 27 , The workspace 22 is in the middle area 26 from a first material 40 manufactured. The border area 28 consists of a second material 42 and thus provides an elastic range 44 in the middle section 26 are the second material 42 and a first material 40 at least partially arranged at the same time. So shows 3 one from the first material 40 existing plastic molded part with ribs 29 extending radially from the center 27 extend away and over flanks 29 ' in a substantially flat plate 30 pass. The plastic molding is at least partially with the second material 42 encapsulated and subsequently by the second material 42 at least partially surrounded. A flexibility in terms of an elastic range 44 but only in the border area 28 achieved. Here is not the first material 40 intended. In the middle area 26 the membrane 20 is located in 3 Partly a layered structure, so to speak.

LIST OF REFERENCE NUMBERS

20

 membrane

22

 Workspace

24

 attachment section

26

 the central region

27

 Focus

28

 border area

29

 rib

29 '

flank

30

 Plate

40

 first material

42

 second material

44

 elastic range

60

 container

62

 container halves

64

 headspace

66

 fluid space

80

 reinforcing element

Ap

 pressure ratio

d

thickness

e

 membrane level

r1, r2

 radii

Claims (10)

Membrane of a container, in particular of a pressure expansion vessel, wherein the membrane ( 20 ) within a container ( 60 ) and a workspace ( 22 ), which is responsible for a displacement in the container ( 60 ), wherein in the container ( 60 ) a pressure ratio (Δp) on the membrane ( 20 ) can be applied, wherein the working area ( 22 ) at least partially from a first material ( 40 ) which is substantially rigid at the pressure ratio (Δp), and wherein the work area ( 22 ) at least one elastic region ( 44 ) which behaves elastically at the pressure ratio (Δp), whereby the work area ( 22 ) within the container ( 60 ), preferably by the pressure ratio (Δp), is displaceable. Membrane ( 20 ) according to claim 1, wherein the work area ( 22 ) the first material ( 40 ) essentially in a central area ( 26 ) of the membrane ( 20 ), which extends substantially parallel to a membrane plane (E), and wherein the at least one elastic region ( 44 ) around the middle area ( 26 ) is arranged around. Membrane ( 20 ) according to claim 1 or 2, wherein the work area ( 22 ) radially from a center ( 27 ) of the membrane ( 20 ) at least in sections either from the first material ( 40 ) or from the elastic region ( 44 ). Membrane ( 20 ) according to one of claims 2 to 3, wherein the working area ( 22 ) in a cross section substantially perpendicular to the membrane plane (E) at least partially the elastic region ( 44 ) and the first material ( 40 ) having. Membrane ( 20 ) according to claim 4, wherein a thickness (d) of the first material ( 40 ), which extend substantially in a direction transverse to the membrane (FIG. 20 ) to a maximum extent of the elastic region ( 44 ) in this direction is in a ratio of 0.001 to 0.5. Membrane ( 20 ) according to one of the preceding claims, wherein in an edge region ( 28 ) of the membrane ( 20 ) a fastening section ( 24 ) is formed, over which the membrane ( 20 ) between and / or on two container halves ( 62 ) can be arranged, and wherein the edge region ( 28 ) the at least one elastic region ( 44 ). Membrane ( 20 ) according to claim 6, wherein the attachment portion ( 24 ) at least one reinforcing element ( 80 ), preferably a plastic and / or a metal ring. Membrane ( 20 ) according to any one of the preceding claims, wherein the first material ( 40 ) has a lower permeability than a second material ( 42 ), and wherein the elastic region ( 44 ) from the second material ( 42 ) is formed. Membrane ( 20 ) according to one of the preceding claims, wherein without concern of the pressure ratio (Δp) the ratio of an area of the first material ( 40 ) to a surface of the elastic region ( 44 ) is in a range of 0.001 to 0.7. Container arrangement, in particular pressure expansion vessel, comprising a container ( 60 ) and a membrane ( 20 ) from a first material ( 40 ) the membrane ( 20 ) a workspace ( 22 ), which is responsible for a displacement in the container ( 60 ), wherein in the container ( 60 ) a pressure ratio (Δp) on the membrane ( 20 ) can be applied, wherein the working area ( 22 ) from a first material ( 40 ) which is substantially rigid at the pressure ratio (Δp), and wherein the work area ( 22 ) at least one elastic region ( 44 ) which behaves elastically at the pressure ratio (Δp), whereby the work area ( 22 ) within the container ( 60 ), preferably by the pressure ratio (Δp), is displaceable.

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