Assembly with a steam generator and a water connection tank

Abstract

Assembly (10), in particular in a cooking appliance, comprising a steam generator (12) and a water connection tank (14) separate from the steam generator (12), which is fluidly connected to the steam generator (12), wherein a level sensor (48) is provided, via which a level (50) in the water connection tank (14) can be determined and which is arranged in a drain path of the water connection tank (14), characterized in that the level sensor (48) is a capacitive level sensor (48) and that the water connection tank (14) has a first fluid connection (20a) which is directly in flow communication with an outlet of the steam generator (12), as well as a second fluid connection (20b) which can be connected to a fresh water supply and a third fluid connection (20c) which is directly in flow communication with an inlet of the steam generator (12).

Description

[0001] The invention relates to an assembly comprising a steam generator and a water connection container separate from the steam generator according to the preamble of claim 1, as it can be used in particular in a cooking appliance which has a steam cooking function.

[0002] The steam generator produces steam, which creates a humid cooking atmosphere inside the appliance. This is available in addition to hot air, allowing cooking in hot air, hot steam, and a mixed atmosphere. Cooking appliances that can utilize these different cooking atmospheres are called combi steamers and are frequently used in restaurants, canteens, and large-scale catering establishments.

[0003] Various fluids are supplied to the steam generator, including of course the fresh water used to generate the steam, possibly with added flavorings, but also, for example, a cleaning and / or descaling solution, which is supplied to the steam generator and which must be drained from the steam generator after cleaning and / or descaling has been completed.

[0004] These functions can be combined in a water connection tank, which has both a fresh water connection and a fluid drain, and in which fluid connections are also provided through which fresh water and other fluids are supplied to the steam generator and through which the fluid to be disposed of is drained from the steam generator.

[0005] It is useful to monitor the fill level, i.e. the amount of fluid in the steam generator, so that, for example, a control system of the cooking appliance can determine an optimal time to refill water depending on pending process steps of a cooking program that is currently running, or to run a cleaning program in a controlled manner.

[0006] The generic patent US 2010 / 0 126 356 A1 shows a steam generator and a water tank fluidically connected to it. The water tank has a level sensor located in a drain path of the water tank.

[0007] The subsequently published DE 10 2019 102 197 B3 shows a steam generator with a level gauge and several fluid connections.

[0008] In DE 10 2014 210 670 A1 a capacitive level meter for a steam generator is described.

[0009] The object of the invention is to improve level measurement in a steam generator.

[0010] This problem is solved by an assembly according to the preamble of claim 1 in that the level sensor is a capacitive level sensor and the water connection tank has a first fluid connection that is directly connected to an outlet of the steam generator, a second fluid connection that can be connected to a fresh water supply, and a third fluid connection that is directly connected to an inlet of the steam generator. The outlet path forms the flow path along which fluid leaves the steam generator and subsequently the water connection tank.

[0011] The fluid connections can be largely or completely integrated into the water connection tank. The water connection tank has a first fluid connection that is directly connected to an outlet of the steam generator, a second fluid connection that can be connected to a fresh water supply, and a third fluid connection that is directly connected to an inlet of the steam generator. In this way, the fluid interfaces for the steam generator can be integrated into the water connection tank, so that the steam generator only needs one inlet and one outlet. All other fluid connections can be implemented within the water connection tank.

[0012] Capacitive level measurement offers the advantage of low wear and flexible installation. For example, a three-pole capacitive level sensor is used, in particular a capacitive leakage resistance level sensor, which has connections for a ground connection, a supply voltage, and a voltage tap.

[0013] Measurements taken in the outflow path result in smaller level fluctuations than measurements taken in the inflow, where, for example, the foaming of the incoming fresh water or cleaning solution can impair the accuracy of the level measurement.

[0014] Advantageously, a fluid supply path is connected to the steam generator and the discharge path according to the principle of communicating vessels, so that a level measurement in the discharge path reliably provides information about the level in the steam generator.

[0015] The capacitive level sensor preferably comprises a mass element and a measuring element, wherein the mass element is arranged on the water connection container and electrically connected to the measuring element such that the mass element establishes a zero potential in a measuring circuit of the level sensor. In this way, a measuring range can be set easily and with high accuracy.

[0016] The measuring element comprises, for example, electronics located outside the water inlet tank and a measuring probe that extends into the water inlet tank. This allows moisture-sensitive electronic components to be positioned outside the fluid-carrying areas of the assembly, while the measuring probe establishes direct contact with the fluid whose level is to be measured.

[0017] The mass element can be located on the outside of the water connection container, so that the mass element is also protected from direct contact with the fluid.

[0018] The ground element should be a highly electrically conductive metal body that typically does not contain its own electronics. The ground element is usually connected to the measuring element via an electrical conductor.

[0019] The water connection tank is preferably an injection-molded part or a blow-molded part made of a suitable plastic, wherein all partitions inside the water connection tank, which divide it into individual chambers, can be made in one piece with the outer housing.

[0020] The water connection tank is usually manufactured separately from the steam generator.

[0021] The first, second and third fluid connections are preferably located at a lower, steam generator-side end of the water connection tank in the installed position, in order to keep the length of the fluid lines between the water connection tank and the steam generator short, among other things.

[0022] The fluid connection between the water connection tank and the steam generator can be established using suitable components, such as flexible fluid lines.

[0023] Preferably, the water connection tank has a level measuring chamber in which the level measurement takes place. In one possible embodiment, the level measuring chamber includes the first fluid connection and a fourth fluid connection, the fourth fluid connection forming an outlet from the water connection tank.

[0024] The fourth fluid connection is preferably located at an upper end of the level measuring chamber, so that fluid flowing out of the steam generator must completely pass through the level measuring chamber before being discharged from the water connection tank.

[0025] The fourth fluid connection can be the sole fluid outlet of the assembly's regular drainage path. The regular drainage path preferably runs from the steam generator outlet, via the first fluid connection, into the level measuring chamber, and from the fourth fluid connection into a connected drain line. Naturally, it is also possible to provide an emergency overflow in the water connection tank, which can also ensure the protection of drinking water.

[0026] In this example, the measuring probe preferably protrudes into the level measuring chamber and may, if necessary, be inserted into the level measuring chamber up to the first fluid connection.

[0027] The fourth fluid connection is preferably located at an upper end of the level measuring chamber.

[0028] The mass element can be located at the upper end of the level measuring chamber.

[0029] Preferably, the water connection tank has a predefined positioning structure that specifies an exact position for the mass element and thus simplifies the correct attachment of the mass element to the housing of the water connection tank.

[0030] The water inlet tank can have several chambers, one of which forms the level measuring chamber. The level measuring chamber preferably has a flow connection to the third fluid connection exclusively via the steam generator, so that the fluid inlet of the steam generator within the water inlet tank has no flow connection to the level measuring chamber, and the entire fluid exchange between the inlet of the steam generator and the level measuring chamber occurs exclusively via the steam generator. A direct flow connection between a fresh water inlet and the level measuring chamber is also not provided.

[0031] In one possible example, the measuring element is located in a branch line of the drain line from the level measuring chamber. The drain line is connected directly to the fourth fluid connection. Fluid from the steam generator and the water tank is discharged via this drain line. The branch line, on the other hand, can serve solely to mount the measuring element on the water tank.

[0032] The level measuring chamber can be vented via the drain pipe.

[0033] When operating a pump connected to the drain line, its function can be checked using the level gauge.

[0034] Naturally, the measuring element should be sealed and inserted into the branch line, but the branch line is normally dry, so that the measuring element and especially its electronics do not come into contact with fluid during normal operation.

[0035] A suitable sealing contour can be formed in the wall of the branch line, so that no separate seals are needed.

[0036] Preferably, the water connection tank is designed so that the entire fluid filling and emptying of the steam generator can take place via the water connection tank.

[0037] During operation, it is not necessary to disconnect the water tank from the steam generator.

[0038] When installed, the water inlet tank preferably extends parallel to the steam generator, so that, according to the principle of communicating vessels, the water level in the water inlet tank, particularly in the level measuring chamber, is directly related to the water level inside the steam generator. It is advantageous that the level measuring chamber, while in flow connection with the interior of the steam generator, is spatially separated from it, so that water movements inside the steam generator during steam generation have no influence on the level measurement. Thus, level measurement is also possible while the steam generator is in operation.

[0039] In addition to the fluid connections for the inlet and outlet of the steam generator and the fresh water connection, further fluid connections may be provided on the water connection tank, for example for a supply of cleaning solution and / or descaling solution or an overflow that represents an emergency drain.

[0040] With the exception of the fourth fluid connection, which forms the fluid outlet, all other fluid connections can be located at a lower end of the water connection tank. This allows the main fluid interfaces to be spatially grouped and positioned near the fluid connections of the steam generator.

[0041] During normal operation of the steam generator, only small amounts of fluid are exchanged between the water inlet tank and the interior of the steam generator, corresponding to the water consumption within the generator. Larger fluid movements occur primarily when fluid is pumped out of the steam generator under specific operating conditions, such as cleaning and / or descaling. Therefore, only minimal water movement occurs in the level measuring chamber, allowing for very precise level measurement.

[0042] The fourth fluid connection can be used to connect a pump that can pump fluid out of the steam generator. The pump can be positioned, for example, between the water tank and the steam generator, i.e., between the steam generator's outlet and the first fluid connection.

[0043] The invention is described in more detail below with reference to an exemplary embodiment and the accompanying figures. The drawings show: - Fig. 1 a schematic perspective representation of an assembly according to the invention consisting of a water connection tank and a steam generator; - Fig. 2 a schematic sectional view of the water connection tank made of Fig. 1; - Fig. 3 a schematic perspective view of the water connection tank made of Fig. 1; - Fig. 4 a schematic representation of the arrangement of a level sensor in the assembly according to the invention; and - Fig. 5 a schematic representation of a fastening of the water connection tank made of Fig. 1.

[0044] Fig. Figure 1 shows an assembly 10 consisting of a steam generator 12 and a water connection tank 14 for installation in a cooking appliance not shown, for example an appliance for professional applications in restaurants, commercial kitchens, canteens and the system catering industry.

[0045] In general, the cooking appliance in which assembly 10 is used has a cooking chamber in which food can be cooked in a controlled atmosphere. This atmosphere can be modified by changing the temperature, flow rate, and humidity. The humidity of the cooking chamber atmosphere can be controlled by the steam generator 12, which uses an integrated heating element (not shown) to produce steam from supplied water, which is then directed into the cooking chamber. Inside the steam generator 12 is a boiler that holds a water reservoir (not shown).

[0046] The water connection tank 14 is a component separate from the steam generator 12, which is attached to the outside of the steam generator 12 and does not protrude into the interior of the steam generator 12.

[0047] The water connection tank 14 is aligned here parallel to the steam generator 12, whereby Fig. Figure 1 shows the installation position in the cooking appliance. The direction V indicates the vertical direction.

[0048] A mounting opening 18 is provided in a rear wall 16 of the water connection tank 14 (see also Fig. 5), which is attached to a mounting bracket 19 on the steam generator 12. The mounting opening 18 has a non-circular contour, so that the position and orientation of the water connection tank 14 relative to the steam generator 12 is precisely defined and the water connection tank 14 cannot rotate relative to the steam generator 12 even when mounted. Instead of the mounting bracket 19, a mounting bolt with a circular outer contour could also be used, in which case anti-rotation is achieved by an additional mounting point.

[0049] In this example, at least during normal operation, the fluid supply and discharge from the steam generator 12 takes place exclusively via the water connection tank 14.

[0050] The water connection tank 14 has a number of separate fluid connections for this purpose, which serve to supply fluid to the steam generator 12.

[0051] A first fluid connection 20a, a second fluid connection 20b and a third fluid connection 20c are arranged side by side at a lower end 22 of the water connection tank 14.

[0052] An interior space 24 of the water connection tank 14 is divided into several chambers by several partition walls 26a, 26b, 26c, which are formed in one piece with the rear wall 16, as well as two side walls 28a, 28b.

[0053] The second fluid connection 20b can be connected to a fresh water supply 30. From the second fluid connection 20b, the fresh water is routed through a channel 32 in the interior 24 of the water connection tank 14 or via a suitable hose (not shown) to an upper end 34 of the interior 24 of the water connection tank 14, from where it enters a water chamber 36, which is part of the interior 24. The water chamber 36 terminates at the lower end 22 in the third fluid connection 20c. This is connected via a fluid line 38 to an inlet of the steam generator 12 (not shown). The steam generator 12 is supplied with fluid via the water chamber 36.

[0054] The water chamber 36 forms one of the chambers separated by the partition walls 26a, 26b, 26c and the side walls 28a, 28b. The fresh water supply channel 32 could also be realized as a chamber formed in this way.

[0055] The partition wall 26a separates the water chamber 36 from a level measuring chamber 40, which in this example forms the leftmost chamber, laterally bounded by the side wall 28a (see Fig. 2).

[0056] The level measuring chamber 40 opens at its lower end 22 into the first fluid connection 20a, which in turn is connected via a fluid line 42 to an outlet of the steam generator 12 (not shown in detail).

[0057] In this example, a pump 44 is located between the outlet of the steam generator 12 and the first fluid connection 20a, which can, for example, in a cleaning mode pump fluid from the water boiler of the steam generator 12 and move it into the level measuring chamber 40.

[0058] At its upper end 45, the level measuring chamber 40 opens into a fourth fluid connection 20d, which is connected to a drain line 46. Fluid can be removed from the assembly 10 and the cooking appliance by operating the pump 44. The drain line 46 also serves as a vent line for the level measuring chamber 40.

[0059] Assembly 10 comprises a capacitive level sensor 48, which detects a level 50 in the level measuring chamber 40. The level sensor 48 is a capacitive leakage resistance level sensor.

[0060] In this example, the level sensor 48 comprises a measuring element 52 and a mass element 54, which is connected to the measuring element 52 via an electrical conductor 56 (not shown) and defines a zero potential for a measuring circuit of the capacitive level sensor 48. The measuring circuit is, for example, integrated directly into the measuring element 52.

[0061] The level gauge 48 also includes a measuring probe 58, which is directly connected to the measuring element 52 and extends into the level measuring chamber 40.

[0062] The data measured by the level sensor 48 is transmitted, for example, to a control unit of the cooking appliance. This can be done via an electrical cable or wirelessly. The level sensor 48 can be connected to the cooking appliance for power supply.

[0063] The measuring element 52 is inserted into the drain line 46 in such a way that only the measuring probe 58 protrudes into the interior of the water connection tank 14, while an electronics 60 of the measuring element 52 is arranged outside the water connection tank 14.

[0064] In this example, a branch line 62 is provided on the drain line 46, into which the measuring element 52 is inserted. Under normal operating conditions, the branch line 62 is dry; nevertheless, the measuring element 52 should be sealed when inserted into the branch line 62. For this purpose, a sealing contour is formed on an inner surface of the branch line 62 in this example.

[0065] The branch line 62 forms a short stub that protrudes from the actual drain line 46. The measuring element 52 is inserted into the open end of the branch line 62 without any further seal, so that the sealing contour provided on the inside of the open end rests against the outside of the measuring element 52.

[0066] A positioning structure 66 for the mass element 54 is provided in an outer wall 64 of the level measuring chamber 40. The mass element 54 is attached to the outer wall 64 from the outside, so that it does not come into contact with the fluid inside the water connection tank 14. The positioning structure 66 defines a precise position for the mass element 54.

[0067] In this example, the positioning structure 66 and thus the mass element 54 is located in the area of ​​the upper end 45 of the level measuring chamber 40, close to the fourth fluid connection 20d, but another location could also be chosen.

[0068] Both the measuring element 52 and the mass element 54 are attached to the water connection container 14 in a non-destructive manner, so that the entire level meter 48 can be replaced if necessary.

[0069] The level gauge 48 is arranged in a drain path of the water connection tank 14, which runs from the steam generator 12 via its drain to the first fluid connection 20a through the level measuring chamber 40 to the fourth fluid connection 20d into the drain line 46 and through which the fluid leaves the steam generator 12 and the water connection tank 14.

[0070] Since the water chamber 36, the level measuring chamber 40 and the water boiler of the steam generator 12 are in flow communication during normal operation of the cooking appliance, a hydraulic equilibrium is established, and the level in the level measuring chamber 40 is a direct measure of the level in the water boiler of the steam generator 12. However, the level in the level measuring chamber 40 is not influenced by the movements of the fluid in the steam generator 12, for example, when the water is heated there to generate steam.

[0071] At the upper end 34 of the water chamber 36, which coincides with the upper end of the interior 24, a further fluid connection 20e is provided, which is directly connected to a vent of the assembly 10, so that air can escape from the interior 24. The normal fill level 50 is significantly below the upper end 34.

[0072] The partitions 26b, 26c define a cleaning solution chamber 68, which opens at its lower end 22 into a further fluid connection 20f, through which a cleaning solution and / or a descaling solution can be added as needed. The cleaning solution chamber 68 has a flow connection at its upper end 70 to the water chamber 36, formed by the separation of the two partitions 26b, 26c. The added cleaning and / or descaling solution thus enters the water chamber 36 from above and mixes with the fresh water present there. The cleaning solution and / or descaling solution can then be fed to the water boiler of the steam generator 12 via the inlet of the steam generator 12 and pumped out again via the outlet and the level measuring chamber 40. In this process, the level measuring chamber 40 and the level meter 48, in particular its measuring probe 58, are also cleaned and / or descaled.

[0073] The partition wall 26c, together with the side wall 28b, also defines an overflow chamber 72, which leads into a further fluid connection 20g, and through which fluid can flow out of the interior 24 if the maximum fill level is exceeded. For this purpose, the fluid connection 20g is connected to an overflow line 74 (see Fig. 1).

[0074] The transition from water chamber 36 to overflow chamber 72 is lower than the fresh water supply to water chamber 36, but higher than the opening of the cleaning solution chamber 68, and is formed by a curved upper end 76 of the partition 26c. This ensures that no water can flow back into the fresh water supply and that cleaning solution only enters water chamber 36, but not overflow chamber 72.

[0075] Since the supply and discharge of all fluids required for operation are carried out entirely via the water connection tank 14, the steam generator 12 is connected to the water connection tank 14 only via the two fluid lines 38, 42. Therefore, it may be sufficient for the steam generator 12 to have only two fluid connections.

[0076] The fluid lines 38, 42 lead here to connections integrated into the pump 44, and the pump 44 is connected to the steam generator 12 via a suitable interface.

[0077] In this example, the water connection tank 14 is made entirely of a plastic material, e.g., using an injection molding, blow molding, or 3D printing process. The water connection tank 14 can be assembled from two individual parts, for example, a tank section to which the side walls 28a, 28b and the partitions 26a, 26b, 26c are integrally molded and which preferably also includes the fluid connections, and a lid that is placed on the tank section and welded to it to seal the interior 24 from the environment.

Claims

[1] Assembly (10), in particular in a cooking appliance, comprising a steam generator (12) and a water connection tank (14) separate from the steam generator (12), which is fluidly connected to the steam generator (12), wherein a level sensor (48) is provided, by which a level (50) in the water connection tank (14) can be determined and which is arranged in a drain path of the water connection tank (14), characterized by , that the level sensor (48) is a capacitive level sensor (48) and that the water connection tank (14) has a first fluid connection (20a) which is directly connected to an outlet of the steam generator (12) in flow communication, as well as a second fluid connection (20b) which can be connected to a fresh water supply and a third fluid connection (20c) which is directly connected to an inlet of the steam generator (12) in flow communication. [2] Assembly (10) according to claim 1, characterized by, that the capacitive level sensor (48) comprises a mass element (54) and a measuring element (52), wherein the mass element (54) is arranged on the water connection tank (14) and is electrically connected to the measuring element (52) such that the mass element (54) provides a zero potential in a measuring circuit of the level sensor (48). [3] Assembly (10) according to claim 2, characterized by , that the measuring element (52) comprises electronics (60) arranged outside the water connection tank (14) and a measuring probe (58) extending into the water connection tank (14). [4] Assembly (10) according to one of claims 2 and 3, characterized by , that the mass element (54) is arranged on the outside of the water connection tank (14). [5] Assembly (10) according to any of the preceding claims, characterized by, that the water connection tank (14) has a level measuring chamber (40) in which the level measurement takes place, wherein the level measuring chamber (40) has the first fluid connection (20a) and a fourth fluid connection (20d) which forms a drain from the water connection tank (14). [6] Assembly (10) according to claim 5, characterized by , that the fourth fluid connection (20d) is located at an upper end (45) of the level measuring chamber (40). [7] Assembly (10) according to claim 2 and one of claims 5 and 6, characterized by , that the mass element (54) is arranged at an upper end (45) of the level measuring chamber (40). [8] Assembly (10) according to one of claims 5 to 7, characterized by, that the water connection tank (14) has several chambers, one of which is the level measuring chamber (40) and the level measuring chamber (40) has a flow connection with the third fluid connection (20c) exclusively via the steam generator (12). [9] Assembly (10) according to one of claims 2 to 4 and one of claims 5 to 8, characterized by , that the measuring element (52) is arranged in a branch line (62) of a drain line (46) of the level measuring chamber (40), wherein in particular the drain line (46) is directly connected to the fourth fluid connection (20d).

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