BUFFER STORE

Abstract

The present invention relates to a buffer store comprising a closed vessel housing for accommodating a storage fluid, in particular water, wherein the vessel housing has at least one inlet opening, for the filling of the vessel housing with the storage fluid, and at least one equalization opening, which fluidically connects the vessel housing to the surroundings and permits a fluidic equalization with the surroundings. According to the invention, a gas-tight cover is also provided in the interior of the vessel housing, which cover is capable of reliably protecting the storage fluid against mixing with other fluids, for example the ambient air.

Claims

1. A buffer store, comprising: a closed vessel housing to hold a storage fluid, especially water, wherein the vessel housing has at least one inlet opening for filling the vessel housing with the storage fluid, and at least one equalization opening, which connects the vessel housing fluidically to the surroundings and makes possible a fluidic equalization with the surroundings, as well as a gas-tight cover in the interior of the vessel housing, which is capable of reliably protecting the storage fluid against mixing with other fluids, such as the ambient air.

2. The buffer store as claimed in claim 1, wherein the gas-tight cover is flexible at least for a portion.

3. The buffer store as claimed in claim 1, wherein the gas-tight cover has a filmlike structure at least for a portion.

4. The buffer store as claimed in claim 1, wherein the gas-tight cover has at least one compensation area, which can compensate for a change in volume of the storage fluid by expanding or contracting the gas-tight cover in the compensation area or the storage fluid can be raised or lowered.

5. The buffer store as claimed in claim 1, wherein the gas-tight cover is firmly joined to the vessel housing in the area of its outer circumference, for example, being clamped, glued, welded or screwed on.

6. The buffer store as claimed in claim 1, wherein the gas-tight cover is double-walled and/or multilayered at least for a portion.

7. The buffer store as claimed in claim 1, wherein the gas-tight cover at least for a portion has a lower density than the storage fluid.

8. The buffer store as claimed in claim 1, wherein the gas-tight cover is formed as a film which floats at least for a portion on the storage fluid, especially the water.

9. The buffer store as claimed in claim 8, characterized in that the film is secured in the vessel housing in such a way that the film can follow a change in volume of the storage fluid in the compensation area, in particular it can be raised and lowered by floating on the storage fluid.

10. The buffer store as claimed in claim 9, characterized in that the compensation area is chosen such that, when the vessel is filled with storage fluid having a temperature of 20 degrees Celsius, the nominal filling height in the vessel housing defines a lower end of the compensation area, while an upper end of the compensation area is defined by a fill level of the storage fluid in the vessel housing that is produced when the storage fluid is heated to a temperature of 95 degrees Celsius.

11. The buffer store as claimed in claim 4, characterized in that the compensation area is chosen such that volume changes of the storage fluid can be equalized up to 20% of the storage volume of the buffer store.

12. The buffer store as claimed in claim 1, characterized in that the gas-tight cover is a film made of ethylene-propylene-diene terpolymer or comprises an ethylene-propylene-diene terpolymer.

13. The buffer store as claimed in claim 8, characterized in that the film comprises a thickness of 0.5 to 5 mm, preferably 1 mm to 4 mm, especially preferably 1.5 to 3 mm and most especially preferably 2 mm+/0.2 mm.

14. The buffer store as claimed in claim 1, wherein the vessel housing may have on its inner circumference a mounting rail, especially a clamping rail, for the gas-tight mounting of the gas-tight cover.

15. A buffer store as in claim 1 wherein the buffer store is adapted for operation with heating water as the storage fluid for a heating plant and includes at least one of a rubber boat for an easier maintenance; a pump system; a stirring system; a vessel heating system; or a connection system for connecting to further system components in proximity to the buffer store.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0088] The invention is described more closely below with reference to the enclosed figures.

[0089] The figures show multiple features of the invention in combination with each other. Of course, the person skilled in the art may also consider them in isolation from each other and also combine them into other meaningful combinations without needing an inventive step for this.

[0090] There are shown schematically:

[0091] FIG. 1 is a buffer store according to the invention in a front view;

[0092] FIG. 2 is the buffer store according to the invention of FIG. 1 in a partial sectioned representation;

[0093] FIG. 3 is an optional configuration of the buffer store according to the invention;

[0094] FIG. 4 is a buffer store according to the invention in a second, slightly modified embodiment, in a sectional representation;

[0095] FIG. 5 is the buffer store according to the invention of FIG. 4 in a second sectional representation;

[0096] FIG. 6 is an enlarged cutout of region VI of FIG. 5 in a schematic representation;

[0097] FIG. 7 is a view of the overflow for the first filling and the respective emergency overflow from arrow direction VII of FIG. 6; and

[0098] FIG. 8 is a schematic representation of an outlet of the buffer store, especially for the feeding of a heating plant.

DETAILED DESCRIPTION

[0099] The figures show a buffer store according to the invention, which is denoted generally by reference number 10. It comprises a vessel housing 12, which stands on a base 14 and is closed with a lid 16.

[0100] The buffer store 10 according to the invention preferably comprises an insulation and a jacketing in the exemplary embodiment. It is preferably provided that the vessel housing 12 comprises an inner shell, forming the actual vessel, and an outer jacketing with an insulation to keep heat in the buffer store 10. In FIG. 2, the outer jacketing with the insulation is schematically given the reference number 36.

[0101] Moreover, it is provided that the bottom and/or the roof of the buffer store 10 or the base 14 and/or the lid 16 of the buffer store 10 are also insulated per the prior art, although this is not otherwise denoted in FIG. 2.

[0102] In its upper region, the vessel housing 12 comprises an equalization opening 18, by which the vessel housing 12 is fluidically connected to the surroundings. Finally, in the lower region of the vessel housing 12, one or more outlet cocks 20 are provided, making possible a draining of the storage fluid from the interior of the vessel housing 12 to the outside. These may also be used for the filling or for the operation of the vessel housing 12 with storage fluid, depending on the design.

[0103] In the upper region of the vessel housing 12 there is furthermore provided a gas-tight cover 22 beneath the equalization opening 18. This is joined firmly by its outer circumference to the inner circumference of the vessel housing 12 and it divides the interior of the vessel housing 12 into a space for the storage fluid (storage space 24) and an equalization space or air space 26.

[0104] The cover 22 is connected gas-tight to the inner circumference of the vessel housing 12.

[0105] The storage space 24 and the air space 26 (equalization space) are thus separated from each other gas-tight in the exemplary embodiment.

[0106] In the embodiment shown, the gas-tight cover 22 is flexible and comprises a filmlike structure with a compensation area 22a. In the exemplary embodiment, the gas-tight cover 22 is formed as a film. The gas-tight cover 22 is configured as a bag open at the top (opened at the top toward the air space 26) and situated inside the vessel housing 12 such that it is connected by its upper edge firmly to the inner wall of the vessel housing 12 or to a mounting rail 12a formed or arranged inside the vessel housing 12 (denoted by reference number 28).

[0107] For this, the gas-tight cover 22 may be everted in its edge region across the mounting rail 12a and/or glued, welded, clamped, screwed and/or otherwise fastened to it.

[0108] Alternatively, the gas-tight cover 22 may also be joined directly to the vessel wall, without an additional mounting rail 12a or the like being needed for this. The connection to the inner wall of the vessel housing 12 may also be produced with the aid of known tensioning systems. A further alternative possibility for fastening the gas-tight cover 22, especially when it is formed as a film, is presented below with the aid of FIG. 3, again only schematically.

[0109] Upon change in volume of the storage fluid in the storage space 24, the preferably bag-shaped compensation area 22a of the gas-tight cover 22 is forced in its lower region in the direction of the air space 26 (everted, so to speak) or lifted up and thereby making possible the compensation for the change in volume in the storage space 24. At the same time, air in the air space 26 is compressed in this way or vented through the equalization opening 18 to the surroundings. If the volume of the storage fluid in the storage space 24 then decreases once more, the compensation area 22a of the gaseous cover 22 rebounds once again due to the negative pressure formed in the storage space 24. The resulting negative pressure in the air space 26 means that ambient air is drawn in through the equalization opening 18 into the air space 26 and thus prevents an unwanted negative pressure inside the vessel housing 12.

[0110] In the schematic representation of FIG. 2, the bottom side of the bag-shaped gastight cover 22 lies flat on the water surface of the storage fluid (preferably a specially treated water such as is used to avoid corrosion in heating plants). Of course, however, the support surface may also differ from the one shown, depending on the fill level of the storage fluid.

[0111] As can be seen from FIG. 2, the buffer store 10 according to the invention may also have an emergency overflow 38. The emergency overflow 38 is preferably formed as a siphon, so that no air can get in from the outside. The emergency overflow 38 makes it possible for storage fluid to drain out from the storage space 24, if the fill level of the storage fluid should expand beyond the maximum water fill level. The emergency overflow 38 is therefore located preferably, as shown in FIG. 2, at a level or in a plane which corresponds to or defines the maximum water fill level. The maximum water fill level corresponds preferably to the upper end of the compensation area 22a, as is likewise represented in FIG. 2. The lower end of the compensation area 22a is preferably chosen such as was already explained in the general part of the specification (nominal fill level of the storage fluid at a temperature of 20 degrees Celsius or optionally also at 10 degrees Celsius or defined by a range at a temperature between 10 degrees Celsius and 20 degrees Celsius).

[0112] Thanks to the gas-tight cover 22 according to the invention, an especially simple and cost-effective solution is provided, which on the one hand compensates for a pressure equalization due to a change in volume of the storage fluid inside a vessel housing 12 of a buffer store 10 and on the other hand prevents an unwanted oxidation of metallic materials of the buffer store 10, the buffer store system and/or a heating plant, which may be part of the buffer store system. In this case, no additional cost-intensive arrangements are needed, such as a device for spraying an inert gas into the air space 26.

[0113] To enhance the safety, however, it may be provided that instead of the ambient air an inert gas such as nitrogen is brought into the air space 26. It can then be provided preferably that the gas is not given off to the outside atmosphere through the equalization opening 18, but instead a basically known pressure equalization system or an equalization tank is used. Of course, nitrogen for example may also be given off to the outside atmosphere through the equalization opening 18. In this case, systems are then preferably provided to ensure a refilling of the air space 26 with nitrogen or another inert gas if the volume of the storage fluid in the storage space 24 is again reduced.

[0114] FIG. 3 shows as an example another advantageous possibility of connecting a gastight cover 22, especially a film, in gas-tight manner to the vessel housing, especially the inner wall of the vessel housing. For this, a channel 30 is provided, being a water channel filled with water in the exemplary embodiment. In order to fasten or tension or clamp the gas-tight seal 22 or the film, clamping, fastening or tensioning means are provided inside the channel 30 (not described in greater detail). Another kind of fastening may also be provided. The water introduced in the channel 30 reliably prevents a gas from getting in, especially air from the air space 26 getting into the storage space 24.

[0115] FIG. 3 also shows as an example a catwalk 32 above and a catwalk 32 beneath the gas-tight seal 22, by which maintenance work can be facilitated. The use of only one catwalk 32 above or beneath the gas-tight seal is also possible. The catwalks 32 are preferably positioned such that the channel 30 or in general the region where the gastight seal 22 is attached to the vessel housing 12 can be reached.

[0116] The figures also indicate a maintenance access 34, for example in order to bring in a rubber boat with which the gas-tight seal 22 can be driven for maintenance purposes, especially when it involves a film. Moreover, a manhole 40 can be provided (see FIG. 2) in order to get into the interior of the storage space 24.

[0117] FIGS. 4 to 8 show a buffer store 10 in a second embodiment, although the features shown with respect to the buffer store of FIGS. 1 to 3 can also be used in the buffer store of FIGS. 4 to 8, and vice versa.

[0118] FIGS. 4 and 5 show the buffer store according to the invention in two different viewing directions, each time in a sectional representation.

[0119] The buffer store 10 once again comprises a base 14, which is preferably formed by stainless steel plates or metal plates provided with a corrosion layer. The vessel housing 12 may have an insulation 36. Moreover, a lid 16 is likewise shown in FIGS. 4 and 5, having an advantageous tilt toward the horizontal. The maintenance access 34 is preferably situated in a side wall of the vessel housing 12 in the area of the equalization space 26.

[0120] As can be seen moreover from FIGS. 4 and 5, the buffer store 10 comprises an inlet line 42 with a preferably central inlet 44 and an outlet line 46 with a preferably central outlet 48. Basically, multiple inlet and outlet lines 42, 46 or inlets 44 and outlets 48 can also be provided.

[0121] FIG. 8 shows schematically an outlet 48 with an outlet line 46. The outlet 48 and the outlet line 46 serve for taking the storage fluid present in the buffer store to a use, especially to feed a heating plant with it. For this, the outlet 48 has a relatively large-area extension in a horizontal direction, preferably substantially parallel to the base 14. The outlet 48 may have at least one upper plate 48a, which is preferably circular shaped. The cover 22 or the film may lie on the upper plate 48a, as shown schematically, when the level of the storage fluid has dropped correspondingly. Preferably the outlet 48 has a second plate 48b, as shown, being preferably substantially identical to or the mirror image of the plate 48a. The two plates 48a, 48b run plane parallel to each other, but at a spacing from each other, so that outlet openings 48c are formed between the plates 48a, 48b, feeding the outlet line 46. Between the outlet openings 48c, webs 48d may be provided to keep the plates 48a, 48b apart and to stabilize them.

[0122] The represented construction of the outlet 48 prevents the cover 22, especially when designed as a film, from closing the outlet 48 or the outlet openings 48c when the film has dropped down far enough.

[0123] It may be provided that the inlet 44 is designed accordingly.

[0124] FIG. 8 moreover shows schematically a brace 50, being fastened at its ends to preferably oppositely situated inner walls of the vessel housing 12 and serving to support and stabilize the outlet 48, respectively.

[0125] The outlet 48 preferably has an extension in the horizontal direction with a diameter of at least 1 m.

[0126] As can be seen from the representation of FIGS. 4 and 5, the buffer store 10 may preferably comprise a vessel wall of a metal band, extending from a lower end of the vessel in encircling manner with a pitch up to the lid 16. Such a construction is basically familiar.

[0127] FIGS. 4 and 5 also show the compensation area 22a. The lower line of the compensation area 22a denotes a minimum filling height (Min) and the upper line of the compensation area 22a denotes the maximum filling height (Max), as shall be further presented more closely in FIGS. 6 and 7 below.

[0128] In the exemplary embodiment of FIGS. 4 to 7, it is provided that the cover 22 in the embodiment of a film is connected gas-tight by means of a mounting rail 12a or the like to the vessel housing 12 in the area of the maximum filling height. The film 22 thus hangs down or floats accordingly on the storage fluid when the storage space 24 beneath the maximum filling height is filled with the storage fluid.

[0129] Basically, however, it is also possible for the film 22 to be fastened to the vessel housing 12 lower down than is shown in FIGS. 4 to 6. The film 22 may be fastened at the height of the compensation area 22a, i.e., between the minimum filling height and the maximum filling height. However, other configurations are also possible here.

[0130] FIG. 5 shows schematically a filling opening 20, 52, which can serve among other things for filling the buffer store 10 with the storage fluid. The filling opening 52, however, may also be configured such, as is further explained in the following, that it stands in communication with an overflow 54 for the first filling or an emergency overflow 38, so that storage fluid can be drained. Preferably, the inlet opening 52 has a siphon in this area (not otherwise shown), especially in connection with the emergency overflow 38.

[0131] FIGS. 6 and 7 show an especially advantageous configuration of the overflow 54 for the first filling or the emergency overflow 38 basically already mentioned in regard to FIG. 2.

[0132] The invention is not confined to the following configuration, but it is especially suited to forming both an overflow 54 for the first filling and an emergency overflow 38.

[0133] The overflow 54 and the emergency overflow 38 are formed by a preferably doublewalled pipe. As is also seen from viewing FIGS. 6 and 7, the overflow for the first filling emerges in the region of the minimum filling height in the storage space 24. In the exemplary embodiment, the overflow 54 emerges just above the minimum filling height in a vertically extending pipe 56, having a lower piece 56a and an upper piece 56b, on which respective openings are formed. The lower piece 56a of the vertically extending pipe 56 is situated distinctly below the minimum filling height of the storage fluid and is therefore generally surrounded by storage fluid. The upper piece 56b of the vertically extending pipe 56 is situated in the region of the hanging of the film 22 or the mounting rail 12a. In the exemplary embodiment, the upper piece 56b is moreover situated in the region of the maximum filling height. The upper piece 56b is preferably angled and extends, for reasons yet to be explained below, at least for a portion of its length also in the horizontal direction and preferably has multiple openings, distributed along the horizontal segment. However, it may also be provided that an opening is located only at the end of the horizontal segment.

[0134] During the first filling of the buffer store or generally during the filling of the buffer store with storage fluid, the storage fluid rises in the buffer store and reaches the lower end of the lower piece 56a of the pipe 56. The storage fluid then rises in the lower piece 56a until it reaches an entrance 58, preferably having a siphon. The storage fluid then flows from the entrance 58 into the overflow 54 and from there to an outlet opening, preferably to an outlet opening which is combined with the inlet opening 52 or is preferably at least situated in spatial proximity to it.

[0135] As soon as storage fluid drains out from the overflow 54, the attendant recognizes that the minimum filling height has been reached and the filling process can be terminated. The overflow 54 for the first filling can then also be blocked, at least in a lower region (not shown) where the outlet is situated, preferably in the region of the inlet opening 52. This will prevent storage fluid from emerging in normal operation through the overflow 54 for the first filling. This is not desirable. In normal operation, the storage fluid, usually having a temperature of 10 degrees Celsius during filling, will expand any way through the entrance 58, so that a flowing of the storage fluid through the overflow 54 should be prevented.

[0136] In the exemplary embodiment an emergency overflow 38 is designed such that it is also connected to the entrance 58 and thus to the vertical pipe 56. However, the emergency overflow 38 extends from the entrance 58 at first in the vertical direction upward, and far enough so that the upper end of the emergency overflow 38 is located at the maximum filling height. This ensures that no storage fluid will flow out through the emergency overflow 38 during normal operation below the maximum filling height. Only when the storage fluid has risen so far in the buffer store 10 that the maximum filling height is reached will storage fluid drain out through the emergency overflow 38. It is provided that a siphon is formed in the region of an outlet opening (not shown) of the emergency overflow 38, especially in the lower region of the vessel housing 12, so that no oxygen can get in through the emergency overflow 38. Thus, a double siphon system is created together with the entrance 58, which likewise preferably has a siphon, which reliably prevents oxygen from getting into the storage space 24 during normal operation.

[0137] The outlet of the emergency overflow 38 is once again preferably combined with the inlet opening 52 or preferably situated at least in spatial proximity to it.

[0138] The buffer store 10 represented in the exemplary embodiment moreover has an emergency air inlet 60. The emergency air inlet 60 has a vacuum relief valve 62. The emergency air inlet 60 serves for preventing a damaging of the film 22 in event of a pipe rupture or if too much storage fluid has accidentally been drained off. If the storage fluid drops below the minimum filling height or drops so far that the film 22 can no longer keep up with it, a negative pressure or vacuum would be formed in the storage space 24 beneath the film 22, so that the film 22 might become damaged. In this case, it is provided that the emergency air inlet 60 opens, for which the vacuum relief valve 62 will serve. Basically, the emergency air inlet 60 can be realized in various designs. The embodiment described below is, however, especially suitable.

[0139] In the exemplary embodiment it is provided that the emergency air inlet 60 at first emerges into the emergency overflow 38, which in turn stands in communication with the entrance 58. The entrance 58, as described, is connected to the pipe 56. As soon as the storage fluid has dropped so far that the entrance 58 lies above the storage fluid, which in the exemplary embodiment also means that the storage fluid has dropped below the minimum filling height, the entrance 58 upon further dropping on account of the negative pressure in the buffer store 10 will be free of fluid, even if it has a siphon, to such an extent that a connection will exist to the emergency air inlet 60 and to the vacuum relief valve 62, respectively. Upon dropping of the pressure below a defined level, the vacuum relief valve 62 opens, so that air can flow in, getting through the entrance 58 into the pipe 56 and from there to the upper piece 56b, which is already clear and exposed. From here, the air then flows into the storage space 24. In order to prevent the film 22 from covering the upper piece 56b of the pipe 56, the latter preferably runs for a partial length also in the horizontal direction, preferably in the region of the maximum filling height, and it preferably comprises multiple openings, so that the air can flow out in suitable manner.

[0140] The equalization opening 18 shown in FIG. 6 leads in the simplified representation directly to the outside or constitutes a connection to the surroundings or to a pressure vessel. However, the equalization opening 18 may also preferably be led downward by a line (not shown) and emerge from the buffer store 10 preferably in spatial proximity to the inlet opening.

[0141] In the exemplary embodiment, it is preferably provided that the outlet line 46 or the outlet 48 situated at the top in the buffer store 10 is used both to supply and to remove storage fluid, especially to bring in warm or heated storage fluid or to remove it from the buffer store 10.

[0142] The outlet line 46 or the outlet 48 may in particular serve for supplying externally heated storage fluid and/or removing warm storage fluid from the buffer store in order to supply a heating plant with it.

[0143] In the exemplary embodiment it may be provided (not shown) that the buffer store 10 has two, three, four, five or more outlet lines 46 and/or outlets 48, especially multiple upper plates 48a and lower plates 48b, on which the cover 22 can be supported.

[0144] In the exemplary embodiment it is preferably provided that the inlet line 42 or the inlet 44 situated at the bottom in the buffer store 10 can be used both to supply and to remove storage fluid, in particular to bring in cold or unheated storage fluid or to remove storage fluid from the buffer store 10.

[0145] The inlet line 42 or the inlet 44 may in particular serve for supplying storage fluid and/or removing storage fluid from the buffer store in order to heat it externally, especially by surplus energy.

[0146] The film 22 may basically have a suitable construction. It is provided in the exemplary embodiment that the film 22 has at least two layers, preferably three layers, where the second, preferably middle layer is gas impermeable, for example being formed by an aluminum foil.

[0147] In a manner not otherwise shown, the film 22 may also have an insulation. Moreover, alternatively or additionally in not otherwise shown manner it may also be provided that an insulation is placed on the surface of the film 22 facing toward the equalization space 26, preferably in the form of beads, preferably styrofoam beads.