Device and method for indirectly measuring level of pressurized liquid in fluid container

Abstract

The invention relates to a device for indirectly measuring the filling level of a pressurized liquid in a fluid container, in particular in the form of a liquid gas container, comprising a connecting piece and / or a line section which can be connected to the connecting piece, said connecting piece and / or line section being connectable to a connection of the fluid container and by means of the connection, the liquid level of the pressurized liquid in the fluid container being measured indirectly. The connecting piece and / or the pipeline section has a fluid channel on or in which at least one temperature sensor for measuring the temperature of the fluid in the fluid channel is arranged; and a fill level determination device, which is connected to the temperature sensor and is designed to measure a temperature profile of the fluid taken out of the fluid channel over a predeterminable time period by means of the at least one temperature sensor during a process of taking the fluid out of the fluid container, and determining the liquid level in the fluid container by means of the measured temperature curve.

Description

Technical Field

[0001] The present invention relates to a device for indirectly measuring the level of a pressurized liquid in a fluid container.

[0002] The invention also relates to a method for indirectly measuring the level of a pressurized liquid in a fluid container.

[0003] The invention further relates to a fluid system comprising a device for indirectly measuring the level of a pressurized liquid in a fluid container and a fluid container. Background Art

[0004] Although generally applicable to any fluid, and particularly liquid gases, the invention is explained in conjunction with a CO2 liquid gas container.

[0005] CO2 tanks or liquid gas containers are used, for example, in the kitchen area to carbonate water in order to produce "soda water". To this end, the carbon dioxide tank or liquid gas container is connected to the corresponding line of the carbonation device in the base cabinet. The user can then output it using appropriate sanitary fittings. In this case, CO2 liquid gas containers usually contain liquid CO2.

[0006] Since CO2 liquid gas containers in the kitchen area must be replaced frequently due to the nature of use, it is very important for the user to know the current filling level. In order to determine the filling level, it is known that the remaining liquid CO2 is determined based on the consumption known based on tests, taking into account the safety reserve. However, this has the disadvantage that the CO2 container is displayed to the user as "empty" even though it still contains CO2. Another disadvantage is that when a new, but only partially filled container is used, the filling level is determined too high, so that the CO2 liquid gas container is already empty, even if the display shows that the container is still partially filled. This is annoying for the user because they are often unable to replace it in time. For liquid gas containers in other application areas, acoustic measurements as well as temperature measurements and weight measurements on the container wall are used.

[0007] Gravimetric measurement is mainly used in filling plants and is disadvantageous in the kitchen area due to cost and mechanical complexity.

[0008] Acoustic measurement has the disadvantage, in particular, that the acoustic measuring head must be pressed very firmly against the container wall in order to achieve sufficient acoustic coupling. Another disadvantage is that such a measurement can only indicate whether there is still liquid or gas in the container at the measuring point. Therefore, for a display with several intermediate steps / levels, several measuring heads are required. Acoustic measurement also has the disadvantage that, based on its principle, the measurement results obtained when using aluminum containers and small volumes are inaccurate. The acoustic measuring head must also be arranged directly on the surface of the container made of metal. Stickers and films interfere with the acoustic measurement, making this method unsuitable for small liquid gas containers that are commonly found in households or kitchens.

[0009] Thermal measurements on flat outer walls can only indicate in a point-like manner whether liquid or gas is present at the measuring point. Another disadvantage is that the measurement is only possible if the gas has been removed to a sufficient extent, since the container must cool down significantly due to the removal process. Here too, a good coupling of the temperature sensor to the outer wall is necessary.

[0010] Other known devices and methods are known, for example, from US Pat. No. 3,161,050A or CN107218983A. Summary of the invention

[0011] It is therefore an object of the present invention to provide a more precise, cost-effective and at the same time more flexible device for determining the filling level of a fluid container and a corresponding method, wherein the device allows for a higher user satisfaction.

[0012] Another object of the present invention is to provide an alternative device for determining the filling level of a fluid container, an alternative fluid system and an alternative method for determining the filling level of a fluid container.

[0013] In one embodiment, the present invention achieves the above objects by a device for indirectly measuring the level of a pressurized liquid in a fluid container, in particular in the form of a liquid gas container, comprising:

[0014] A connecting piece and / or a pipe section connectable to the connecting piece, wherein the connecting piece and / or the pipe section can be connected to a connecting part of a fluid container and gas can be taken out of the fluid container by means of the connecting part, the connecting piece and / or the pipe section having a fluid channel, at least one temperature sensor for measuring the temperature of a fluid in the fluid channel being arranged on or in the fluid channel, and

[0015] A liquid level determining mechanism is connected to a temperature sensor and is designed to measure a temperature curve of a fluid taken out of a fluid channel within a predefined time period by means of at least one temperature sensor during a process of taking fluid from a fluid container, and to determine a liquid level in the fluid container by means of the measured temperature curve.

[0016] In one embodiment, the present invention achieves the above object by a method for indirectly measuring the level of a pressurized liquid in a fluid container, the method comprising the following steps:

[0017] providing a connecting piece and / or a pipeline section connected to the connecting piece having a fluid channel, in which at least one temperature sensor for measuring the temperature of a fluid in the fluid channel is arranged,

[0018] Connect the fittings and / or tubing segments to the outlet of the fluid container,

[0019] Take a certain amount of gas from the fluid container,

[0020] determining a temperature profile of the gas removed within a predeterminable period of time by means of at least one temperature sensor, and

[0021] The level of the liquid in the fluid container is determined based on the measured temperature curve.

[0022] In one embodiment, the present invention utilizes a fluid system to achieve the above-mentioned purpose, which fluid system includes a device for indirectly measuring the liquid level of a pressurized liquid in a fluid container according to any one of claims 1 to 8 and a fluid container connected to the connecting parts and / or pipeline sections of the device.

[0023] One of the advantages achieved thereby is that the fill level in a fluid container, in particular in the form of a liquid gas container, can be measured in a reliable manner. Another advantage is that the sensor does not have to be arranged directly at, in or on the container, but rather downstream of the container opening, which enables the fluid container to be easily replaced. Furthermore, the advantage is that user satisfaction is significantly increased, in particular due to a more precise measurement and a more reliable display of the fill level of the fluid container.

[0024] The term "fluid" is to be understood in the broadest sense and refers, in particular in the claims and preferably in the description, to a liquid, a liquid mixture, a gas, a gas mixture or a combination thereof.

[0025] The term "tank" is to be understood in the broadest sense and refers, in particular in the claims and preferably in the description, to any type of container for containing one or more fluids, which is in particular arranged to be replaceable.

[0026] The term "sanitary" is to be understood in the broadest sense and, in particular in the claims and preferably in the description, generally refers to the kitchen area, the bathroom or laundry area and the heating area.

[0027] Additional features, advantages, and further embodiments of the present invention are described below or are disclosed thereby.

[0028] According to an advantageous improvement of the present invention, at least one additional sensor, in particular two additional sensors, are arranged at different positions along the fluid channel. This has the advantage that the temperature curve can be measured more accurately at different locations, thereby improving the measurement accuracy as a whole.

[0029] According to another advantageous improvement of the invention, the connection piece is designed as a pressure reducer. This has the advantage that the user does not have to purchase and arrange additional components, but the integrated component that the user usually has to use already has the corresponding sensor for determining the liquid level. This also increases user satisfaction.

[0030] According to another advantageous development of the invention, temperature sensors are arranged at the inlet and outlet of the pressure reducer. This has the advantage that the liquid level can be determined in a simple and at the same time particularly reliable manner by means of the sensors in the pressure reducer without changing the basic structure of the pressure reducer.

[0031] According to another advantageous development of the invention, the liquid level determination device is designed to determine the liquid level based on the amount of fluid removed. One of the advantages achieved thereby is that a more precise liquid level determination can be made. If a defined removal amount is predetermined, a temperature drop can occur in a particularly reliable manner on the one hand via the removal amount and on the other hand via the liquid level; in addition, if necessary, an earlier liquid level can be determined based on a previous removal process and the current liquid level can then be inferred based on this.

[0032] According to another advantageous development of the invention, a display device, in particular an optical one, is provided, which is designed to display the filling level between 0% and 100% at least in steps of 25%, in particular at least in steps of 20%, preferably at least in steps of 10%, and the display device is connected to the filling level determination device, in particular wirelessly. This has the advantage that the filling level is indicated to a sufficient degree for the user, so that the user can promptly purchase a new, filled fluid container. If a wireless connection is used, the laying of cables, etc. can be avoided as much as possible.

[0033] According to another advantageous development of the invention, at least the connecting piece and / or the pipeline section is made of plastic. This has the advantages of cost-effective production and easy integration of one or more temperature sensors.

[0034] According to another advantageous development of the invention, the replacement of the fluid container can be detected by means of a liquid level determination device, in particular by detecting a pressure drop at a connection and / or a line section. This has the advantage that the determination device automatically discards the liquid level that has been determined so far and determines the liquid level as soon as the liquid gas is released.

[0035] According to another advantageous development of the invention, a temperature drop within a predeterminable time period is determined to determine the filling level. This makes it possible to determine the filling level of the fluid container in a simple and reliable manner.

[0036] According to another advantageous development of the invention, for determining the filling level, a comparison is made with a previously determined comparison diagram representing different filling levels. One of the advantages achieved thereby is that the filling level can be determined in a particularly simple and reliable manner.

[0037] According to another advantageous development of the invention, the time measured from the start of gas removal until the temperature drops by at least 0.5° C., in particular at least 1.0° C., preferably at least 2.0° C., in particular at least 5.0° C., is determined for determining the filling level. This has the advantage that a possibly heated gas cushion can be removed and at the same time it can be determined how long it takes until a significant temperature drop occurs due to gas expansion during the removal process, which represents additional information about the previous filling level.

[0038] According to another advantageous development of the invention, the ambient temperature of the fluid container is determined and the determined ambient temperature is used to determine the fill level. In this way, the measured temperature curve can be set in relation to the ambient temperature, so that, for example, small temperature drops at higher ambient temperatures can be determined more accurately and such temperature drops can be compensated, or the measured temperature curve can be normalized to a predeterminable temperature.

[0039] According to another advantageous development of the invention, the temperature curve is determined only after a predeterminable period of time. This can save energy, so that no measurement is performed when a heated gas cushion is present in the connection piece and / or the pipeline section.

[0040] Further important features and advantages of the invention are revealed in the dependent claims, the drawings and the associated description of the figures.

[0041] Of course, the features mentioned above and those still to be explained below can be used not only in the combination specified in each case but also in other combinations or alone, without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Preferred designs and embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components or elements.

[0043] in:

[0044] Figure 1 An apparatus according to an embodiment of the present invention is shown in schematic form;

[0045] Figure 2 shows in schematic form the method steps according to an embodiment of the present invention; and

[0046] Figure 3 A temperature-time diagram obtained by means of a device according to an embodiment of the invention is shown in schematic form. DETAILED DESCRIPTION

[0047] Figure 1 A device for indirectly measuring the level of a pressurized liquid in a fluid container is shown.

[0048] exist Figure 1 1 shows a device 1 for indirectly measuring the liquid level of liquid CO2 in a fluid container, in particular a liquid gas cylinder in the form of a CO2 cylinder 2. The cylinder 2 has an opening 2a for taking out CO2. The opening 2a is pressure-tightly connected to the connection 3 of the pressure reducer 5. The output 4 of the pressure reducer 5 is also connected to a pipeline or pipe 6. Temperature sensors 9a, 9b, 9c are arranged in the area of ​​the connection 3, in the area of ​​the output 4 and in the area of ​​the output 4 in the pipeline 6. Here, the temperature sensors 9a, 9b, 9c are connected to a determination mechanism 7, such as a microprocessor. The determination mechanism can also have a display device 8 or can be connected to the display device by wire or wirelessly, so as to visually display the liquid level determined by the determination mechanism 7 to the user, for example in steps of 10%. The determination mechanism 7 is a liquid level determination mechanism, which is designed to: during the process of taking from the CO2 gas cylinder 2, measure the temperature curve of the CO2 gas taken out in one or more fluid channels from the input part 3 to the output part 4 (here, the fluid channel in the pressure reducer 5) and in the pipeline 6 within a predefined time period with the help of temperature sensors 9a, 9b, 9c, and determine the liquid level of the liquid CO2 in the CO2 gas cylinder 2 based on the measured temperature curve.

[0049] Figure 2 The steps of a method according to an embodiment of the present invention are shown.

[0050] exist Figure 2 The steps of a method for indirectly measuring the level of a pressurized liquid in a fluid container are shown in FIG. The method comprises the following steps:

[0051] A connection piece 5 having a fluid channel and / or a pipeline section 6 connected to the connection piece 5 is provided S1, at least one temperature sensor 9a, 9b, 9c for measuring the temperature of the fluid in the fluid channel is arranged on or in the fluid channel,

[0052] Connect the connector 5 and / or the pipe section 6 S2 to the outlet 3 of the fluid container 2,

[0053] Take out S3 a certain amount of gas from the fluid container 2,

[0054] Determining S4 the temperature profile of the gas removed within a predeterminable time period by means of at least one temperature sensor 9a, 9b, 9c, and

[0055] The level of the liquid in the fluid container 2 is determined S5 based on the measured temperature profile.

[0056] Figure 3 Shown is a temperature-time diagram obtained by means of a device according to an embodiment of the invention.

[0057] exist Figure 3 1 shows a graph of the temperature 11 measured when CO2 is taken out of a CO2 cylinder in relation to time 10. The measured temperature curve of graph line 20 corresponds to a CO2 cylinder that is approximately 2 / 3 filled, the measured temperature curve of graph line 21 corresponds to a CO2 cylinder that is approximately 1 / 3 filled, and the measured temperature curve of graph line 22 corresponds to a CO2 cylinder that is almost empty.

[0058] The measured temperature curve can be explained as follows. The pressurized gas in a fluid container (e.g. a compressed gas cylinder) cools significantly during the withdrawal process, i.e. during the transition from the liquid phase to the gas phase. In order to be able to detect the pressure even when withdrawing small amounts, a corresponding temperature sensor for measuring the temperature of the CO2 gas can be arranged as close as possible to the outlet on the compressed gas cylinder. For example, the temperature sensor can be arranged in the pressure reducer and / or directly after the pressure reducer, as shown in FIG. Figure 1 As shown. Instead of arranging multiple temperature measuring sensors along the wall of the compressed gas cylinder as in the case of the known level determination mechanism, it is also possible to arrange only one temperature measuring sensor. Since the temperature sensor in or after the pressure reducer is located outside the area to be serviced by the user, the operation and arrangement of the temperature sensor is significantly less prone to error.

[0059] During each withdrawal, a corresponding amount of CO2 changes from the liquid state to the gaseous state. This requires energy, which is initially taken from the medium, the liquid CO2 itself. This leads to a cooling of the surface of the liquid CO2. Since liquid CO2 is a better conductor of heat than gaseous CO2, the energy initially comes mainly from the liquid portion. If there is still a lot of liquid CO2 in the bottle, there is only a small gaseous cushion. This leads to a rapid drop in temperature at the outlet of the CO2 cylinder. If there is only a small amount of liquid CO2 left in the bottle, the CO2 cushion above the liquid / gas limit is significantly larger. Since gases are generally poor conductors of heat, it takes longer for the temperature at the withdrawal site to drop. Especially when the withdrawal amount is known, the difference in temperature changes can be used to determine the liquid level of the liquid CO2 in the cylinder.

[0060] For this purpose, for example, the maximum value of the temperature change (normalized to the minimum value reached by the starting value) or the measurement point at a specific time in the corresponding diagram 20, 21, 22 can be used. The ambient temperature only plays a role if it should be above the boiling point of the CO2 gas, because it is a relative thermometry.

[0061] Methods and apparatus according to embodiments of the present invention may be used with any gas in a container that is present in liquid form in a bottle and that can be withdrawn in a proportionate or partial gaseous form.

[0062] In graph 20, the temperature drop is the greatest, since here there is still the most liquid CO2 in the fluid container compared to the other two graphs. Graph 21 also shows a strong temperature drop, however, it is not as strong as in graph 20. In graph 22, there is almost no liquid CO2 in the fluid container, so there is little or no cooling, i.e. no temperature drop can be detected anymore.

[0063] To determine the filling level, a comparison can now be made with reference to a comparison line normalized to 0° C. These comparisons can also be predefined for different withdrawal amounts. To determine the filling level, the comparison line can also be interpolated in order to determine the filling level as accurately as possible.

[0064] Thereby, the filling level can be indicated precisely to the user, in particular in steps of 25%, 20%, 10% or even 5%.

[0065] In summary, at least one embodiment of the present invention has at least one of the following advantages and / or provides at least one of the following features:

[0066] High user satisfaction.

[0067] Cheap to manufacture or implement.

[0068] High flexibility.

[0069] Simple and fast level measurement with high accuracy.

[0070] High reliability in determining the fill level of a gas in a fluid container, in particular a pressurized gas container.

[0071] Although the present invention has been described in connection with preferred embodiments, it is not limited thereto but can be modified in many ways.

[0072] Reference numerals list

[0073] 1 Device

[0074] 2 CO2 cylinders

[0075] 2a Access opening

[0076] 3. Connection

[0077] 4 Output section

[0078] 5 Connectors / pressure reducers

[0079] 6 Pipeline Sections

[0080] 7 Liquid level determination mechanism

[0081] 8 Display device

[0082] 9a, 9b, 9c Temperature sensor

[0083] 10 Time in seconds

[0084] 11 Temperature, in °C

[0085] 20 Temperature curve

[0086] 21 Temperature curve

[0087] 22 Temperature curve

[0088] S1 to S5 Method steps

Claims

1. A device (1) for indirectly measuring the level of a pressurized liquid in a fluid container (2), in particular in the form of a liquid gas container, comprising: A connection piece (5) and / or a pipeline section (6) that can be connected to the connection piece (5), wherein the connection piece (5) and / or the pipeline section (6) can be connected to a connection part of a fluid container (2), and gas can be removed from the fluid container (2) by means of the connection part, wherein the connection piece (5) and / or the pipeline section (6) has a fluid channel, on or in which at least one temperature sensor (9a, 9b, 9c) is arranged for measuring the temperature of the fluid in the fluid channel, and A liquid level determining mechanism (7) is connected to a temperature sensor (9a, 9b, 9c) and is designed to: during a process of taking fluid from a fluid container (2), measure a temperature curve (20, 21, 22) of a withdrawn fluid in a fluid channel within a predeterminable time period by means of at least one temperature sensor (9a, 9b, 9c), and determine the liquid level of the liquid in the fluid container (2) by means of the measured temperature curve (20, 21, 22).

2. The device (1) according to claim 1, characterized in that At least one further sensor, in particular two further sensors (9a, 9b, 9c) are arranged at different locations along the fluid channel.

3. The device (1) according to any one of claims 1 to 2, characterized in that The connecting piece (5) is designed as a pressure reducer.

4. The device (1) according to claim 2 and 3, characterized in that Temperature sensors (9a, 9b, 9c) are arranged on the input and output of the pressure reducer.

5. The device (1) according to any one of claims 1 to 4, characterized in that The liquid level determination mechanism (7) is designed to determine the liquid level based on the amount of fluid taken.

6. The device (1) according to any one of claims 1 to 5, characterized in that A display device (8), in particular an optical one, is arranged, which is designed to display the liquid level between 0% and 100% at least in steps of 25%, in particular at least in steps of 20%, preferably at least in steps of 10%, and is connected to the liquid level determination device (7), in particular wirelessly.

7. The device (1) according to any one of claims 1 to 6, characterized in that At least the connecting piece (5) and / or the pipeline section (6) are made of synthetic material.

8. A device (1) according to any one of claims 1 to 7, characterized in that A replacement of the fluid container can be detected by means of the filling level determination device (7), in particular by detecting a pressure drop at the connection piece (5) and / or the line section (5).

9. A method for indirectly measuring the level of a pressurized liquid in a fluid container (2), the method comprising the following steps: Providing (S1) a connecting piece (5) having a fluid channel and / or a pipeline section (6) connected to the connecting piece (5), on or in which at least one temperature sensor (9a, 9b, 9c) is arranged for measuring the temperature of a fluid in the fluid channel, Connecting (S2) a connector (5) and / or a pipe section (6) to an outlet (3) of a fluid container (2), A certain amount of gas is taken out (S3) from the fluid container (2), determining (S4) a temperature profile (20, 21, 22) of the gas removed within a predetermined time period by means of the at least one temperature sensor (9a, 9b, 9c), and The level of the liquid in the fluid container (2) is determined (S5) based on the measured temperature curve (20, 21, 22).

10. The method according to claim 9, characterized in that In order to determine ( S5 ) the filling level, the temperature drop within the predeterminable time period is determined.

11. The method according to any one of claims 9 to 10, characterized in that To determine (S5) the liquid level, a comparison is made with previously determined comparison graphs representing different liquid levels.

12. The method according to any one of claims 9 to 11, characterized in that To determine ( S5 ) the filling level, the time is determined from the start of gas withdrawal until the temperature drops by at least 0.5° C., in particular at least 1.0° C., preferably at least 2.0° C., in particular at least 5.0° C.

13. The method according to any one of claims 9 to 12, characterized in that The ambient temperature of the fluid container (2) is determined and the fill level is determined using the determined ambient temperature.

14. The method according to any one of claims 9 to 13, characterized in that The temperature profile (20, 21, 22) is determined only after a predeterminable period of time.

15. A fluid system comprising a device (1) for indirectly measuring the liquid level of a pressurized liquid in a fluid container (2), in particular in the form of a liquid gas container, according to any one of claims 1 to 8, and a fluid container (2) that can be connected to a connector (5) and / or a pipeline section (6) of the device (1).

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