Water shortage treatment method for steam cooking equipment and steam cooking equipment

Abstract

The present invention relates to a method for processing water shortage of a steam cooking device, wherein the steam cooking device comprises an external steam generator and a water tank connected to the steam generator; during the steam cooking process of the steam cooking device, when there is no water in the water tank and the remaining water M in the steam generator can be obtained, the working time T of the steam generator is calculated according to M, the current working power P of the steam generator, and the temperature difference ΔT between the current temperature in the steam working cavity and the target temperature; T is compared with the water shortage alarm time threshold condition corresponding to the current working stage of the steam cooking device, thereby determining whether to issue a water shortage prompt. The method for processing water shortage of the steam cooking device can more accurately judge the matching between the remaining water in the steam generator and the cooking time when the water tank is short of water, thereby solving the problem of unnecessary interruption of cooking. The present invention also relates to a steam cooking device using the aforementioned water shortage processing method.

Description

Technical Field

[0001] This invention relates to a method for handling water shortage in a steam cooking device with an external steam generator, and also to a steam cooking device using this method. Background Technology

[0002] Cooking appliances with external steam generators are typically used in conjunction with a water tank. The water tank is connected to the steam generator to supply water to it. During operation, a water level detector is usually installed in the water tank to monitor the water level. If the detector detects that there is no water in the tank, it will trigger a water shortage alarm and stop the cooking appliance from operating.

[0003] For example, Chinese invention patent CN101943394B (application number 201010262658.1), entitled "Steam Generator and Household Electric Steamer," discloses an electric steamer that, when operating, if there is no water or insufficient water in the water tank, a water level detection device will send a signal, triggering an alarm and simultaneously cutting off the power supply to the steam generator 17, causing the steamer to stop working. Additionally, Chinese invention patents CN101822489B (application number CN201010114441.6), entitled "Household Steamer," and CN101390706B (application number CN200810063721.1), entitled "A Household Multifunctional High-Temperature Electric Steamer," both disclose steamers that employ the aforementioned water shortage alarm method.

[0004] However, in practical applications, even if the water tank is empty, it doesn't necessarily mean the steam generator is short of water. If the water level in the steam generator is sufficient to prepare the current menu, stopping the steamer when the water tank is low will result in unnecessary shutdowns, which will affect the cooking results. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide a method for handling water shortage in a steam cooking device in the context of water shortage in the water tank. This method can more accurately determine the matching between the remaining water in the steam generator and the cooking time, thereby solving the problem of unnecessary interruption of cooking.

[0006] The second technical problem to be solved by the present invention is to provide a steam cooking device that applies the aforementioned method, in contrast to the prior art.

[0007] The technical solution adopted by the present invention to solve the first technical problem mentioned above is: a method for handling water shortage in a steam cooking device, characterized in that: the steam cooking device includes an external steam generator and a water tank connected to the steam generator;

[0008] During the steam cooking process of the steam cooking equipment, when there is no water in the water tank and the remaining water volume M in the steam generator can be obtained, the working time T of the steam generator is calculated based on M, the current working power P of the steam generator, and the temperature difference ΔT between the current temperature in the steam working chamber and the target temperature. T is then compared with the water shortage alarm time threshold condition corresponding to the current working stage of the steam cooking equipment to determine whether to issue a water shortage warning.

[0009] As an improvement, when the preset steam cooking equipment is in the preheating stage, the remaining water volume M can meet the time threshold Ai required for heating work with different power ranges and different temperature rise ranges.

[0010] If the steam cooking equipment is currently in the preheating stage, the corresponding time threshold Ai is determined according to the power range of the working power P and the temperature rise range of the temperature difference ΔT. T is compared with the time threshold Ai. If T > Ai, no water shortage warning is issued; otherwise, a water shortage warning is issued.

[0011] If the steam cooking equipment is currently in the heat preservation stage, compare T with the remaining working time T0 of the steam cooking equipment. If T > T0, no water shortage warning will be issued; otherwise, a water shortage warning will be issued.

[0012] As an improvement, during the steam cooking process of the steam cooking equipment, when there is no water in the water tank and the remaining water in the steam generator cannot be obtained, the temperature rise rate K in the steam generator is calculated. If K > K0, a water shortage warning is issued, where K0 is the temperature rise rate threshold for judging that the steam generator is running dry due to water shortage.

[0013] Preferably, a first water level detector is installed in the steam generator at a set water level;

[0014] When there is no water in the water tank, when the water level in the steam generator drops to the detection level of the first water level detector, the remaining water volume M1 in the steam generator can be calculated based on the current working power P1 of the steam generator. At this time, a water shortage warning is issued. The remaining water volume M1 in the steam generator is calculated as follows: M1 = S*h*ρ, where S is the bottom area of ​​the steam generator, h is the height of the steam generator electrode probe from the bottom, and ρ is the density of water.

[0015] The working time T1 of the steam generator corresponding to M1 is T1 = λ * M1 * C * ΔT / P1, where λ is a preset correction coefficient and C is the specific heat capacity of water.

[0016] As the steam generator operates, the water level inside the steam generator drops below the level detected by the first water level detector, and the operating power of the steam generator is adjusted to P, which is different from P1. jAt that time, calculate and obtain the remaining water volume M in the current steam generator. j At this point, a water shortage warning is issued; the remaining water volume M in the steam generator is then calculated. j , Where j is a positive integer greater than or equal to 2; corresponding M j The corresponding operating time T of the steam generator j =λ*M j *C*ΔT / P j .

[0017] The technical solution adopted by the present invention to solve the second technical problem mentioned above is: a steam cooking device, characterized in that: the aforementioned water shortage treatment method is applied;

[0018] The steam cooking device includes a cooking pot, a control circuit board, a steam generator disposed outside and connected to the cooking pot, and a water tank disposed outside the cooking pot and connected to the steam generator. A first temperature sensor is disposed inside the cooking pot, a first water level detector and a second temperature sensor are disposed inside the steam generator, and a second water level detector is disposed inside the water tank. The control circuit board is electrically connected to the steam generator, the first temperature sensor, the second temperature sensor, the first water level detector, and the second water level detector.

[0019] Preferably, the first water level detector is a sensor installed at the set water level of the steam generator, and the second water level detector is installed at the bottom of the water tank.

[0020] Compared with existing technologies, the advantages of this invention are as follows: The water shortage handling method for steam cooking equipment in this invention, when there is no water in the water tank but water in the steam generator, calculates the estimated operating time of the steam generator to determine whether to issue a water shortage alarm. This avoids unnecessary shutdowns of the steam cooking equipment caused by water shortage, allowing it to continue operating even when there is water in the steam generator. Especially when the water in the steam generator is sufficient for the current cooking session, it avoids the impact on cooking results caused by water shortage interrupting the cooking process. Attached Figure Description

[0021] Figure 1 This is a flowchart of a water shortage treatment method for a steam cooking device in an embodiment of the present invention. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0023] The steam cooking device in this embodiment includes a cooking pot, a control circuit board, a steam generator located outside and connected to the cooking pot, and a water tank located outside and connected to the steam generator. This differs from steam generation structures where a heating plate is directly installed at the bottom of the cooking pot. The steam generator is externally located relative to the cooking pot, and can be any existing steam generator product. A first temperature sensor is installed inside the cooking pot to detect its operating temperature. The steam generator includes a first water level detector and a second temperature sensor. The first water level detector is located at a set water level in the steam generator. It detects a fixed water level and, when water is introduced into the steam generator from the water tank, the water level reaches the position of the first water level detector. After the first water level detector detects that the water has submerged the water, it controls the water to continue flowing into the steam generator for a fixed delay, thereby causing the water level in the steam generator to exceed the position of the first water level detector. When the steam generator is operating, the water level inside it continuously decreases. Once the water level reaches the position of the first water level detector, the water tank is then controlled to replenish water into the steam generator. A second water level detector is installed inside the water tank. This second water level detector can employ various existing water level sensors. In this embodiment, the second water level detector is located at the bottom of the water tank and is used to detect whether there is water in the tank. The control circuit board is electrically connected to the steam generator, the first temperature sensor, the second temperature sensor, the first water level detector, and the second water level detector.

[0024] This steam cooking equipment can be used with various cooking appliances such as steam ovens and steam-grill combos. This steam cooking equipment operates using the following water shortage handling method.

[0025] Steam cooking appliances typically operate in two phases: a preheating phase and a heat-keeping phase. During the preheating phase, the steam generator operates at high power, causing the temperature inside the cooking pot to rise rapidly. During the heat-keeping phase, the steam generator operates at relatively low power, and the temperature inside the cooking pot is maintained at a temperature slightly below the target temperature. For a standard steam function, the target temperature is usually 100°C.

[0026] The water shortage handling method of this steam cooking equipment is as follows, which is mainly for handling situations where there is no water in the water tank.

[0027] Throughout the entire operation of the steam cooking equipment after it is turned on, the first water level sensor and the second water level detector are used to detect the water level in the steam generator and the water tank.

[0028] like Figure 1As shown, if the water tank is found to be empty upon initial startup, and the water level in the steam generator has not reached the position of the first water level sensor (i.e., the water tank is empty and the remaining water level in the steam generator cannot be determined), then the exact amount of water in the steam generator cannot be accurately determined, nor can the operating time of the remaining water be effectively estimated. Therefore, a second temperature sensor is used to monitor the temperature change inside the steam generator in real time, and the temperature rise rate K is calculated based on the acquired temperature data. If K > K0, it indicates that the steam generator is dry-burning, causing the temperature to rise too quickly, and a water shortage warning is issued. Here, K0 is the threshold for the temperature rise rate used to determine if the steam generator is dry-burning due to water shortage. Users can then add water to the water tank based on the water shortage warning.

[0029] If, during the steam cooking process of the steam cooking equipment, the water tank is found to be empty while the first water level detector can still detect water level information, then cooking does not need to be interrupted. Specifically, when there is no water in the water tank but the remaining water volume M in the steam generator can be obtained, the control continues cooking. Then, based on M, the current operating power P of the steam generator, and the temperature difference ΔT between the current temperature in the steam working chamber and the target temperature, the working time T of the steam generator is calculated. T is then compared with the water shortage alarm time threshold condition corresponding to the current working stage of the steam cooking equipment to determine whether to issue a water shortage warning.

[0030] Regarding the specific detection function of the first water level detector in the steam generator in this embodiment, if the water level in the steam generator is higher than the water level at the location of the first water level detector when there is no water in the water tank, the working time T is not calculated initially. When the water level in the steam generator drops to the detection level of the first water level detector, the remaining water volume M1 in the steam generator can be calculated based on the current operating power P1 of the steam generator. The remaining water volume M1 is calculated as: M1 = S * h * ρ, where S is the bottom area of ​​the steam generator, h is the height of the steam generator electrode probe from the bottom, and ρ is the density of water. The corresponding working time T1 of the steam generator is: T1 = λ * M1 * C * ΔT / P1, where λ is a preset correction coefficient and C is the specific heat capacity of water.

[0031] As the steam generator operates, the water level inside drops below the level detected by the first water level detector. Based on the steam generator's operating power, operating time, and the initial water volume information (M1), the real-time remaining water volume can be calculated. Of course, the operating power of the steam generator may change during operation. For example, if the water tank empties during the preheating phase, the operating power will inevitably change when entering the heat preservation phase, although this change may also occur during the heat preservation phase. Within the same phase, the steam generator may also adjust its operating power according to the specific control strategy. This adjustment involves setting the operating power of the steam generator to a value different from P1. j At that time, calculate and obtain the remaining water volume M in the current steam generator. j At this point, a water shortage warning is also issued. This means that as power changes, the remaining water in the steam generator will affect the operating time, requiring a re-assessment. The current remaining water level M in the steam generator is then calculated. j , Where j is a positive integer greater than or equal to 2; corresponding M j The corresponding operating time T of the steam generator j =λ*M j *C*ΔT / P j .

[0032] A water shortage in the tank can occur during either the preheating or heat preservation phase. In this embodiment, the water shortage detection can be performed in real time based on the availability of the remaining water volume M. Alternatively, it can be detected at specific points in time, such as when the remaining water volume is just available or when the operating power of the steam generator changes.

[0033] The specific water shortage warnings for different stages of steam cooking are as follows.

[0034] The control circuit board of the steam cooking equipment is preset to ensure that the remaining water volume M is sufficient to meet the time threshold Ai required for heating operations with different power ranges and different temperature ranges when the steam cooking equipment is in the preheating stage. Different power ranges refer to the power range set for the working power of the steam generator, and different temperature ranges refer to the temperature range set for the cooking pot's internal temperature relative to the target temperature.

[0035] These preset time thresholds Ai, which are only for different power ranges and different heating ranges, are based on taking into account some specific differences. For example, when the steam generator's operating power is high and the temperature inside the cooking pot is very close to the target temperature, the steam generator will soon stop working or reduce its operating power. In this case, even if the working time T of the water in the steam generator is small based on the current operating power of the steam generator, it is still enough for the steam cooking equipment to work until the preheating stage ends. In this case, the corresponding time threshold Ai can be set to a smaller time value for more accurate judgment and to avoid misjudgment caused by comparison with a more conservative long time threshold.

[0036] For the case where the water tank is empty but the remaining water volume M in the steam generator is available:

[0037] If the steam cooking equipment is currently in the preheating stage, the corresponding time threshold Ai is determined based on the power range of the working power P and the temperature rise range of the temperature difference ΔT. T is compared with the time threshold Ai. If T > Ai, no water shortage warning is issued; otherwise, a water shortage warning is issued.

[0038] If the steam cooking equipment is currently in the heat preservation stage, compare T with the remaining working time T0 of the steam cooking equipment. If T > T0, no water shortage warning will be issued; otherwise, a water shortage warning will be issued.

[0039] If the water tank is empty, but the remaining water in the steam generator is sufficient for the cooking process, the cooking equipment does not need to issue a water shortage warning and can continue cooking. The water shortage handling method in this invention monitors the remaining water level in the steam generator in real time when the water tank is empty, predicting the generator's operating time. This reduces unnecessary water shortage warnings and pauses, especially for dishes with low water requirements, ensuring the cooking process continues smoothly and achieving optimal results.

Claims

1. A method for dealing with water shortage in a steam cooking device, characterized in that: The steam cooking device includes an external steam generator and a water tank connected to the steam generator; During the steam cooking process of the steam cooking device, when there is no water in the water tank and the remaining water M in the steam generator can be obtained, the working time T of the steam generator is calculated according to M, the current working power P of the steam generator, and the temperature difference ΔT between the current temperature in the steam working cavity and the target temperature; T is compared with the water shortage alarm time threshold condition corresponding to the current working stage of the steam cooking device, so as to determine whether to issue a water shortage prompt; During the steam cooking process of the steam cooking device, when there is no water in the water tank and the remaining water in the steam generator cannot be obtained, the temperature rise rate K in the steam generator is calculated. If K>K0, a water shortage prompt is given, where K0 is the temperature rise rate threshold for judging whether the steam generator is dry-burning due to lack of water.

2. The method for handling water shortage of a steam cooking device according to claim 1, characterized in that: When the steam cooking device is in the preheating stage, the remaining water volume M is able to meet the time threshold Ai required for heating work with working parameters in different power ranges and different temperature rise ranges; If the steam cooking device is currently in the preheating stage, the corresponding time threshold Ai is determined according to the power range of the working power P and the temperature rise range of the temperature difference ΔT, and T is compared with the time threshold Ai. If T>Ai, no water shortage prompt is given, otherwise a water shortage prompt is given; If the steam cooking device is currently in the heat preservation stage, T is compared with the remaining working time T0 of the steam cooking device. If T>T0, no water shortage prompt is given; otherwise, a water shortage prompt is given.

3. The method for dealing with water shortage of a steam cooking device according to claim 1 or 2, characterized in that: A first water level detector is provided in the steam generator at a set water level; In the case where there is no water in the water tank, when the water level in the steam generator drops to the detection water level of the first water level detector, the remaining water volume M1 in the current steam generator is calculated based on the working power P1 of the steam generator at this time, and a water shortage prompt is made at this time; at this time, the remaining water volume M1 in the current steam generator is calculated as S*h*ρ, where S is the bottom area of ​​the steam generator, h is the height of the steam generator electrode probe from the bottom, and ρ is the density of water; The working time of the steam generator corresponding to M1 is T1=λ*M1*C*ΔT / P1, where λ is the preset correction coefficient and C is the specific heat capacity of water; As the steam generator works, the water level in the steam generator drops below the detection level of the first water level detector, and the working power of the steam generator is adjusted to P which is different from P1. j When the remaining water volume M in the steam generator is calculated, j At this time, the water shortage prompt is judged; at this time, the remaining water volume M in the current steam generator is calculated j , , where j is a positive integer greater than or equal to 2; the corresponding M j The corresponding working time of the steam generator is T j =λ*M j *C*ΔT / P j .

4. A steam cooking device, characterized in that: Applying the water shortage treatment method as claimed in claim 1 or 2; The steam cooking device comprises a cooking pot, a control circuit board, a steam generator arranged outside the cooking pot and connected to the cooking pot, and a water tank arranged outside the cooking pot and connected to the steam generator. A first temperature sensor is arranged in the cooking pot, a first water level detector and a second temperature sensor are arranged in the steam generator, and a second water level detector is arranged in the water tank; the control circuit board is respectively connected to the steam generator, the first temperature sensor, the second temperature sensor, the first water level detector, and the second water level detector through electrical signals.

5. The steam cooking device according to claim 4, characterized in that: The first water level detector is a sensor arranged at a set water level of the steam generator, and the second water level detector is arranged at the bottom of the water tank.

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