Method and device for filling, compacting and evacuating a vacuum reservoir

Abstract

A method for filling, compacting, and evacuating a vacuum storage tank (2) for storing hot water, wherein the vacuum storage tank comprises at least an inner tank (100) for holding water, an outer tank (200) surrounding the inner tank (100), a connection flange (110) connected to the inner tank (100) for receiving and securing a closure body, and an insulating unit (201) between the inner tank (100) and the outer tank (200), wherein the insulating unit (201) is filled with an insulating material and evacuated, comprising the following steps: a) Initial weighing of the vacuum storage tank (2); b) Initial evacuation of the insulating unit (201); c) Initial filling of the insulating unit (201) with an insulating material; d) Second weighing of the vacuum storage tank (2); e) Initial compaction of the insulating material in the insulating unit (201); f) Second evacuation of the insulating unit (201);g) Determining the filling status in the insulation unit, g1) if filling status < target value, then proceed to process step h); or g2) if filling status = target value, then proceed to process step l); h) Second filling of the insulation unit (201) with insulating material; i) Third weighing of the vacuum storage unit (2); j) Second compaction of the insulating material in the insulation unit (201); k) Third evacuation of the insulation unit (201); l) Closing of the insulation unit (201) of the vacuum storage unit (2) or of the filling and evacuation pipe of the vacuum storage unit (2);

Description

[0001] The invention relates to a method for filling, compressing and evacuating a vacuum storage tank for storing hot water, comprising the features of the preamble of claim 1 and the device for carrying out the method according to claim 7.

[0002] Vacuum storage tanks, such as hot water storage tanks, are used to generate and store hot water, primarily in households. When hot water is drawn from the storage tank, cold water automatically flows into it and is then reheated. These hot water storage tanks are available in various sizes and storage capacities. Depending on the size and intended use, the installation and setup of the hot water storage tank also vary. For example, some hot water storage tanks are designed to be wall-mounted.

[0003] Wall-mounted hot water storage tanks typically have a cold water inlet, a hot water outlet, a heating element, a temperature sensor, an impressed current anode or a magnesium anode, and a safety temperature sensor in their lower section, all leading into the interior of the tank. A disadvantage of this design is that these components and their openings each create a heat transfer path from the inside of the tank to the outside. Particularly in the case of vacuum-insulated hot water storage tanks, there is a high need for continuous optimization to reduce heat transfer from the tank to the outside.

[0004] German patent application DE 102017209782 A1 discloses a method for the thermal insulation of an evacuable container. EP 3995772 A1 discloses a method for compressing the pipe element for filling and evacuation, as well as a compression tool for carrying out the method.

[0005] A storage container, especially one made of steel, has the disadvantage that a kind of funnel forms in the center during the suction phase of the insulation material. The insulation material adheres to the walls of the container, resulting in insufficient insulation in the center and creating an air pocket. Consequently, the vacuum pump draws in air instead of insulation material. The resulting problem is an insufficient amount of insulation material and uneven thermal insulation within the vacuum storage unit. This also poses the additional risk that the material adhering to the walls of the storage container will suddenly fall into the center, potentially causing blockages in the system's pipes. A vibrator that sets the storage container in motion can remedy this situation.The storage container is set in motion, shaking the insulation material inside. Disadvantages include the purchase and operating costs of the vibrator, and the vibrations can also negatively affect the welds of the storage container and the device.

[0006] From DE 10 2017 209 782 A1, a method for thermal insulation of an evacuable container is known, comprising an inner container, an outer container, and a cavity located between the inner container and the outer container, wherein a) a pressure in the cavity is reduced by means of a vacuum pump and, after reaching a first pressure value, the connection to the vacuum pump is interrupted, b) a connection is subsequently established between a storage container of the thermally insulating, particulate material and a filling opening provided in the region of the cavity, c) the evacuable container is set in motion, whereby the thermally insulating, particulate material flows into the cavity according to a) and the pressure in the cavity increases due to the air introduced with the thermally insulating, particulate material, d) the filling is stopped at a second pressure value by interrupting the connection from the cavity to the storage container, e) step a) is repeated.wherein the power of the vacuum pump used to vent the cavity is regulated such that the time course of the mass flow of air escaping from the cavity, which is introduced with the heat-insulating, particulate material, has a maximum, f) steps b)-e) are subsequently repeated until the desired degree of filling is reached, and g) as a final step the evacuated cavity is sealed.

[0007] EP 0 101 673 A1 relates to a method for producing a thermally insulated body, e.g. a pipe, with an inner and outer shell, in particular metallic, ... provides that the space formed between the inner and outer shell is filled with a porous, powdered insulating material, evacuated and sealed vacuum-tight.

[0008] Therefore, the object of the invention is to provide a method with optimized process steps, thus enabling a more homogeneous and efficient introduction of the insulation material. In addition to the uniform introduction of the insulation material, complete filling of the vacuum storage tank with the insulation material must be ensured. At the same time, the costs of thermal insulation should be kept low, the method and the associated number of process steps should be minimized, and the device should be optimized accordingly.

[0009] This problem is solved by a method having the features of claim 1 and by the device for filling, compressing and evacuating a vacuum storage tank having the features of claim 7. Advantageous embodiments of the invention are specified in the dependent claims.

[0010] For hot water storage tanks, it is crucial that the temperature of the water inside can be maintained for as long as possible without reheating. To achieve this, excellent insulation is required all around the tank. A vacuum chamber containing the water tank is used for this purpose. An insulating unit between the outer and inner tanks is evacuated and filled with a special insulating powder, typically pyrogenic silica. The insulation thickness is determined based on the required technical parameters. Insulation with an insulating powder is not possible in the lower section of the hot water storage tank. This section contains an opening for a heating element, as well as the connections for the water inlet and outlet, and potentially other components. Therefore, materials with low thermal conductivity are used in the lower section of the hot water storage tank.

[0011] According to the invention, the method relates to a vacuum storage device consisting of an inner container and an outer container surrounding the inner container. A gap is formed between the inner and outer containers, serving as an insulating layer or as a receptacle for an insulating medium. An insulating material is introduced into this insulating unit, and a vacuum is created. This results in very good insulation of the inner container. Once the manufacturing steps of the vacuum storage device are complete, a filling and evacuation line, made of copper in particular, remains attached to the outer container. A subsequent cover conceals the remaining or detached filling and evacuation line. This filling and evacuation line connects the device for filling, compressing, and evacuating the vacuum storage device. The gap...The insulating unit between the inner and outer containers is filled with insulating material, compacted, and then evacuated. Compaction ensures that the insulating material is evenly distributed, creating homogeneous insulation around the inner container.

[0012] The filling, compaction, and evacuation process comprises the following steps: The first step involves determining the actual weight of the vacuum storage tank (initial weighing). Due to manufacturing tolerances, the weight varies slightly from one vacuum storage tank to another. This information is crucial for the process, as it allows for the precise determination of the amount of insulation material to be added in the intermediate steps and at the end.

[0013] The initial evacuation then takes place. The vacuum pump is operated at high power, specifically at > 95% of its capacity, and maintains this constant power for a few minutes, particularly between 2 and 4 minutes. The next step is the initial filling. Filling occurs via pressure equalization. The filling line valve is opened, and the insulation material is conveyed through the filling and evacuation line into the gap of the insulation unit, located between the inner and outer containers of the vacuum storage tank.

[0014] The pressure inside the insulation unit is < 100 mbar, preferably < 50 mbar, but particularly preferably < 5 mbar. The filling status is determined by subsequent weighing (second weighing) and recording the weight of the vacuum reservoir filled up to that point. This method determines the amount of insulation material still required.

[0015] In order to be able to introduce further insulation material into the insulation unit and at the same time achieve homogeneous insulation, the insulation material is compressed in the vacuum storage unit.

[0016] The subsequent second evacuation differs from the first. While the first evacuation aims to create a vacuum quickly and easily, allowing the vacuum pump to operate at high power, the second evacuation requires precise control of the vacuum pump. The problem here is that the insulation material already inside the insulation unit is pulled out again, potentially clogging the vacuum pump and pipes.

[0017] In the next step, the insulation unit could be refilled. At this point, and also at another point in the process, a decision is made regarding further filling. The first weighing determines the weight of the empty vacuum reservoir; the second weighing determines the weight of the vacuum reservoir after the first filling. By calculating the difference between these two weights, the actual amount of insulation material added is determined in weight. This difference is compared to a predetermined target value. If the difference matches the target value, no further filling is necessary. If the difference is less than the target value, further filling is required to achieve a favorable fill level of approximately 100%.

[0018] If the vacuum accumulator is refilled, it is weighed again after refilling to determine its status (third weighing). After the subsequent and renewed compaction (second compaction) of the insulation material in the insulation unit, the final evacuation is carried out. During this process, the vacuum pump valve and the vacuum suction line valve are opened, the vacuum pump is regulated, and a pressure of < 100 mbar, preferably < 50 mbar, but particularly preferably < 5 mbar, is generated in the vacuum accumulator. The vacuum accumulator, or the filling and evacuation line of the vacuum accumulator, can now be closed and disconnected.

[0019] An optional final weighing (fourth weighing) checks the weight one last time and confirms that the procedure was carried out correctly.

[0020] Furthermore, according to the invention, a device for filling, compacting, and evacuating a vacuum storage tank is provided, with which the method according to the invention is carried out. The device consists of a storage container, a vacuum pump, lines, and, in an advantageous embodiment, a total of four valves. The storage container receives the insulating material in powder form, and the flow of the insulating material is directed towards the vacuum storage tank.

[0021] To circumvent the aforementioned problems of air being drawn in instead of the insulation material, the device according to the invention uses a storage container made of plastic, or at least partially made of plastic, or coated with plastic. Replacing the steel storage container with one made of plastic or with one coated with plastic prevents the insulation material from adhering to the walls of the storage container and creating an air pocket.

[0022] The advantageous arrangement of the valves ensures efficient filling, compression, and evacuation. The filling line valve and the vacuum suction line valve are preferably arranged in parallel. The vacuum suction line and the filling line both connect to the filling and evacuation line, which in turn is connected to the vacuum reservoir. A scale on the device ensures that the vacuum reservoir is weighed.

[0023] This weighing method makes it possible to determine the filling status and thus to determine the remaining amount of insulation material to be filled and to introduce this into the insulation unit of the vacuum storage tank in the optional next filling step.

[0024] Preferably, the hot water storage tank has a capacity of up to 300 liters, particularly preferably between approximately 5 and approximately 150 liters.

[0025] Advantages and embodiments of the invention are explained in more detail below with reference to the drawings: Figures:

[0026] Fig. 1 shows a schematic representation of the device for filling, compacting and evacuating a vacuum storage tank. Fig. 2 a sectional view of a vacuum storage tank

[0027] The process for filling, compacting, and evacuating a vacuum storage tank for storing hot water is described using the method described in Fig. 1 illustrated device for filling, compacting and evacuating 1 described. The preferred valve arrangement is discussed. The insulating material is located in the reservoir. 3. The flow of the insulation material is from the storage container. 3 towards vacuum storage 2. Via a reservoir valve 3.1 and the storage tank line 3.2 The insulation material enters the filling line.7 and then via the filling line valve 7.1 and the filling and evacuation line 8 into the insulating unit of the vacuum storage tank 2. The vacuum pump 4 It is regulated according to need and depending on the procedural step.

[0028] The vacuum is created via the vacuum pump valve 4.1 controlled, which is located in the vacuum pump line 4.2 located parallel to the filling line 7, is the vacuum suction line 6 arranged in which the vacuum suction line valve is located 6.1 is located. Both the filling line 7 as well as the vacuum suction line 6 lead into the filling and evacuation line 8. Parallel to vacuum suction line valve 6.1 is the filling line valve 7.1 in the filling line 7 arranged.

[0029] The procedure starts with a) weighing and determining the actual weight of the vacuum storage tank. 2. Following the weighing, the first step is b) evacuation using the vacuum pump. 4 and by opening the vacuum pump valve 4.1 performed. The vacuum pump 4 It is operated at high power, specifically at > 95% of its capacity, and maintains this power level for a few minutes, particularly between 2 and 4 minutes. In the next step, c) the initial filling process begins. The filling line valve 7.1 The container is opened and the insulation material is removed from the storage container. 3 via the filling and evacuation line 8 into the gap of the insulating unit 201 of the vacuum storage tank 2 transported. The pressure in the insulating unit is less than 100 mbar, preferably less than 50 mbar, but particularly preferably less than 5 mbar.

[0030] The weight of the vacuum storage unit is determined via the subsequent weighing step d). 2 determined. In order to be able to introduce further insulation material into the gap and at the same time achieve homogeneous insulation, e) the insulation material is placed in the vacuum storage unit. 2 compacted.

[0031] The subsequent f) second evacuation differs from the a) first evacuation. While in a) the first evacuation a vacuum is created simply and quickly and the vacuum pump 4 Therefore, the vacuum pump can be operated at high power. 4 The second evacuation (f) needs to be precisely regulated. The problem here is that the insulation material, which is already in the insulation unit, 201 is located, is pulled out again and thus the vacuum pump 4 and can clog the pipes.

[0032] In the next step (g), although it can also occur at another point in the process, a decision is made regarding further filling. The weight of the empty vacuum storage tank is known from the first weighing; after the second (or subsequent) weighing, the weight of the vacuum storage tank after the first (or subsequent) filling is known. By calculating the difference between the two weights, the actual amount of insulation material added is determined in weight.

[0033] This means that a difference is calculated between the next weighing (n = 1, 2, 3, ...) and the first weighing. This difference is compared to a predetermined target value. If the difference matches the target value, no further filling is necessary and the process can be completed in the next step. If the difference is less than the target value, further filling is required.

[0034] In very rare cases, overfilling may occur; in such cases, a signal is conveniently sent to the production staff.

[0035] In the advantageous embodiment of the method, the first filling is slightly below full capacity; according to one aspect of the invention, the container is filled to approximately 90%. The remaining quantity is then added in the second filling.

[0036] The decision-making process regarding whether further refilling is necessary can be carried out once or several times during the procedure.

[0037] If the vacuum reservoir is refilled (h), the remaining required amount of insulation material is added to the insulation unit, or, if refilling is not necessary, the process proceeds directly to step I). After filling, the weight of the vacuum reservoir is determined again, and the correctly added quantity is verified. Following the subsequent (j) compaction of the insulation material in the gap of the insulation unit... 201, The final evacuation (k) is carried out. During this process, the vacuum suction line valve is... 6.1 opened, the vacuum pump 4 regulated and generates a pressure of less than 100 mbar, preferably less than 50 mbar, but particularly preferably less than 5 mbar. k) The vacuum reservoir 2 or the filling line of the vacuum storage tank can now be closed.

[0038] An optional final weighing checks the weight one last time and confirms that the procedure was carried out correctly.

[0039] In Fig. 2 is a vacuum storage 2 as seen in a cross-sectional view. The outer container 200 surrounds the inner container 100. Between the outer container 200 and the inner container 100 There is an insulating unit 201, which is filled with insulating material and in which a vacuum exists. The inner container 100 is made from a lid part 120, a coat part 130 and a base part 140 trained. On the inner container 100, especially on the bottom part 140, is a connection flange 110 welded on. The floor 210 of the outer container 200 It is designed in two parts and consists of an inner and an outer ring. The insulating unit 201 It consists of a gap which is filled with an insulating material or medium and then evacuated. Therefore, the insulating unit provides insulation. 201the inner container 100. The outer container 200 Floor 210, a lid 220 and a case 230. A locking element is inserted into the opening. 113 inserted and attached to the connection flange 110 attached. Reference symbol list

[0040] 1 device 2 Vacuum storage 3 Storage container 3.1 reservoir valve 3.2 Storage tank line 4 vacuum pump 4.1 Vacuum pump valve 4.2 Vacuum pump line 5 Connection line 6 Vacuum suction line 6.1 Vacuum suction line valve 7 Filling line 7.1 Filling line valve 8 Filling and evacuation line 100 Inner container 110 Connection flange 113 opening 120 Lid part 130 Coat part 140 bottom part 200 Outer container 201 Insulation unit 210Floor 220 Lid 230 Housing

Claims

1. Method of filling, compacting and evacuating a vacuum storage tank (2) for storing hot water, wherein the vacuum storage tank (2) consists of at least - an inner cylinder (100), - an outer cylinder (200) which surrounds the inner cylinder (100), - a connecting flange (110) connected to the inner cylinder (100) for accommodating and securing a closure body, - an insulation unit (201) between the inner cylinder (100) and the outer cylinder (200), and a filling and evacuation line (8) connected to the vacuum storage tank (2), wherein the insulation unit (201) is filled with an insulation material via the filling and evacuation line (8) and a vacuum is generated in the insulation unit (201), comprising the following steps: a) First weighing of the vacuum storage tank (2); b) First evacuation of the insulation unit (201); c) First filling of the insulation unit (201) with an insulation material; d) Second weighing of the vacuum storage tank (2); e) First compacting of the insulation material in the insulation unit (201); f) Second evacuation of the insulation unit (201); g) Determining the filling status in the insulation unit (201), g1) if filling status < target value, then continue with method step h); or g2) if filling status = target value, then continue with method step l); h) Second filling of the insulation unit (201) with an insulation material; i) Third weighing of the vacuum storage tank (2); j) Second compacting of the insulation material in the insulation unit (201); k) Third evacuation of the insulation unit (201); l) Closing the insulation unit (201) of the vacuum storage tank (2) or the filling and evacuation line (8) of the vacuum storage tank (2);2. Method of filling, compacting and evacuating a vacuum storage tank (2) according to claim 1, characterised in that the filling status is determined by weighing and a differential value is calculated, which results from the first weighing and from a further weighing.

3. Method of filling, compacting and evacuating a vacuum storage tank (2) according to claims 1 and 2, characterised in that the evacuation is carried out by controlling the vacuum pump (4), in which the output of the vacuum pump (4) is adapted to the method step.

4. Method of filling, compacting and evacuating a vacuum storage tank (2) according to claims 1 to 3, characterised in that the insulation unit (201) is brought to a pressure of < 100 mbar, preferably to < 50 mbar, but particularly preferably to < 5 mbar.

5. Method of filling, compacting and evacuating a vacuum storage tank (2) according to claims 1 to 4, characterised in that the method is applied once or several times in succession.

6. Method of filling, compacting and evacuating a vacuum storage tank (2) according to claims 1 to 5, characterised in that pyrogenic silicic acid is used as the insulation material of the insulation unit (201).

7. A device (1) for filling, compacting and evacuating a vacuum storage tank (2) to perform the method according to claim 1, comprising at least: - a storage container (3) for holding insulation material and a storage container line (3.2); - a storage container valve (3.1) in the storage container line (3.2); - a vacuum pump (4) for generating a vacuum in the vacuum storage tank (2) and a vacuum pump line (4.2); - a vacuum pump valve (4.1) in the vacuum pump line (4.2); - a connection line (5) into which the storage container line (3.2) and the vacuum pump line (4.2) exit; - a vacuum suction line (6) and a vacuum suction line valve (6.1) in the vacuum suction line (6); - a fill line (7) arranged parallel to the vacuum suction line (6) and a fill line valve (7.1) in the fill line (7); - a fill and evacuation line (8), and - scales that weigh the vacuum storage tank (2) and determine the filling status.

8. A device (1) for filling, compacting and evacuating a vacuum storage tank (2) according to claim 7, characterised in that the storage container (3) consists at least partly of plastic or has a plastic coating.

9. A device (1) for filling, compacting and evacuating a vacuum storage tank (2) according to claim 7, characterised in that the fill line valve (7.1) and the vacuum suction line valve (6.1) are arranged in parallel.

10. A device (1) for filling, compacting and evacuating a vacuum storage tank (2) according to claim 7, characterised in that the vacuum suction line (6) and the fill line (7) exit into the fill and evacuation line (8), the fill and evacuation line (8) being connected to the vacuum storage tank (2).

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