Evaporation cooking process for eggs with miniature dosing pump

Abstract

Evaporation cooking method, preferably for eggs, in which the evaporation time of a pre-metered, defined reference water quantity taken from a water storage container (1) is used to determine the additional evaporation water quantity and to subsequently add it, characterized in that the pre-metering of the reference water quantity and the add-on dosing are not carried out by gravity via an actuator, but rather with a miniature dosing pump (5), wherein an evaporation tray (9) is preheated before the evaporation of the reference water quantity; wherein a second temperature sensor (11) or a temperature sensor (7) on the evaporation tray (9) is used for preheating the evaporation tray (9), the measured values ​​of which are transmitted to a control unit (2), or the temperature sensors (7, 11) are directly coupled to a temperature switch which transmits its switching signal to the control unit (2) when the target preheating temperature is reached.

Description

[0001] The invention relates to an evaporative cooking process, preferably for eggs.

[0002] DE 20 2012 010 825 U1 discloses a fully automatic egg cooker with integrated egg quenching, which has the following components: cold water humidifier, control with time program sequences for adjusting the egg quality, number of eggs and exactly required evaporation water quantity supply as a default suggestion with subsequent correction options, valves, cold water supply pump.

[0003] DE 10 2010 003 563 A1 relates to a household appliance for steaming food, wherein the household appliance comprises a treatment line through which the food can be transported in the transport direction in order to be treated by steam in the treatment line.

[0004] EP 2 461107 A1 teaches a cooking appliance and a method for steaming the cooking chamber of a cooking appliance with an evaporation device.

[0005] Patent DE 10 2004 031 077 B4 is the first to describe an evaporation cooking process, preferably for eggs, in which the evaporation time of a defined, pre-dosed reference water quantity is used to determine the additional evaporation water quantity and to add it via an actuator. A major difficulty with this system is that the amount of water to be dosed is released using a passive actuator. After the actuator, which has no conveying function, is opened, the water flows from the storage tank into the evaporation tray due to the gravitational pressure of the water column. The problem is that when the fill level in the storage tank is low, the gravitational pressure decreases and, accordingly, the amount of water is lower for the same opening time of the actuator. This can distort the process and prevent the desired hardness of the eggs from being precisely achieved.A large, wide storage container can provide a solution, but this would result in large dimensions for the egg cooker. Another problem is that, unless the evaporation tray is preheated, there are no defined initial thermal conditions for reproducible measurement of the evaporation time.

[0006] The present invention for solving such problems is defined in the appended claim 1. Advantageous further developments emerge from the dependent claims. Short character description: Fig. 1 shows an egg cooker according to an embodiment of the invention. Function / Example:

[0007] The eggs are in the steam chamber of the egg cooker after Fig.1 above the evaporation tray 9. A defined reference water quantity is dosed from the water storage container 1 using the miniature dosing pump 5, the heating 8 of the evaporation tray 9 is switched on, and the time it takes for the water to evaporate is measured. The more eggs there are in the egg cooker, and the larger or colder the eggs are, the longer the evaporation time. This is because the water evaporated in the evaporation tray 9 condenses on the surface of the eggs and drips back into the evaporation tray 9. The evaporation time is recorded after the temperature sensor 7 measures that the boiling temperature has been exceeded. This means that the reference water has evaporated. The evaporation time now forms the measure for the additional amount of evaporation water to be added for the correct hardness of the eggs. The additional amount of evaporation water to be added is determined by the control unit 2 and added using the miniature dosing pump 5.The longer the evaporation time of the reference water quantity, the more or larger the eggs in the egg cooker and the less evaporation water needs to be added. Once the added amount of evaporation water has completely evaporated, which is determined when the boiling point of the temperature sensor 7 is exceeded, the eggs are ready. This can be signaled by an acoustic signal generator. The desired degree of hardness can be preset using the setting switch 3 for the hardness of the eggs. If harder eggs are desired, the control unit 2 determines a larger amount of evaporation water to be added. If the evaporation tray 9 overheats, a bimetal 10, whose switching temperature is defined to be above the boiling point, switches off the heating 8 of the evaporation tray 9.

[0008] According to the invention, an improved evaporation cooking method, preferably for eggs, is proposed, in which the evaporation time of a pre-metered reference water quantity is used to determine the additional evaporation water quantity and subsequently add it. This method is characterized in that the additional addition is not carried out by gravity via an actuator, but rather by a miniature dosing pump 5. Such a pump, which should have high delivery accuracy and good sealing when switched off, can preferably be designed as a diaphragm pump. This allows the pump to have a simple and miniaturized design, ensuring both precise dosing and a long service life with low power consumption.The miniature pump design is particularly important because conventional egg cookers are already very compact and leave no room for bulky additional equipment, which would significantly reduce customer acceptance. A special version of the evaporative cooking process is characterized by the use of a diaphragm pump to meter the water quantity. This pump has closable inlet and outlet valves that are actuated only by the positive or negative water pressure on one side of the oscillating pump diaphragm. These valves open and close without any additional auxiliary power and are therefore less prone to failure and cost-effective.

[0009] In the proposed evaporative cooking process, the evaporation tank 9 can be preheated before the reference water quantity is evaporated. This results in reproducible conditions at different starting temperatures of the evaporation tank 9. This is still heated, for example, if a second cooking cycle is in progress. The preheating temperature sensor 11 or the temperature sensor 7 is used to record the actual preheating temperature and compare it with the setpoint stored in the control system. The temperature measurements of the sensors used are transmitted to the control unit 2, or the sensors are directly coupled to a temperature switch, which transmits its switching signal to the control unit 2 when the setpoint preheating temperature is reached.

[0010] Diaphragm pumps are not completely leak-tight when switched off, as the seals of the inlet and outlet valves allow a small amount of leakage between the suction and discharge sides when the pump is switched off. Preventing this leakage would require an additional shut-off device in the pump line. This would be very complex. A simple way to prevent the water reservoir 1 from partially or completely draining into the evaporation tray 9 when the pump is switched off is to position the outlet opening of the pressure line 6 of the miniature dosing pump 5 above the maximum possible fill level of the water reservoir 1.

[0011] In order to ensure that the miniature dosing pump 5 is always supplied with water, that no air enters the pump housing and that no air can be pumped, it is proposed according to the invention that the suction line 4 of the miniature dosing pump 5 is below the minimum filling level of the water reservoir 1.

[0012] In the event that harder eggs have been preset compared to softer eggs on the setting switch 3, the invention proposes increasing the defined reference water quantity to be dosed. This higher quantity is also determined by the control unit 2. This allows for a longer measurement time to capture the egg surface, which improves the reproducible quality of the desired hardness.

[0013] Temperature sensor 7 measures the temperature of evaporation tray 9. This temperature increases with heating and remains approximately constant once evaporation begins. Evaporation occurs in several phases around the boiling point. Three isothermal sub-regions with slightly different temperature levels were observed. To improve the provision of temperature values ​​for the calculation algorithm of control unit 2, the invention proposes not to process all measured values ​​from temperature sensors 7 and 11 directly, but rather to compute an average over a specific time period using the software of control unit 2 in order to further process meaningful average values.

[0014] The evaporation cooking method, which uses a metered reference amount of water pumped into an evaporation tank with a metering pump. After evaporation, the evaporation time is evaluated to determine the correct amount to add, can be applied not only to eggs, but to any food. This results in an optimal cooking process in which the food is neither overcooked nor undercooked.

[0015] The described evaporative cooking process can also be applied to cooking devices that typically cook food under elevated pressure at elevated temperatures. For example, special pressure cookers could be manufactured. List of reference symbols for Figure 1 1 water storage tank 2 control unit 3 adjustment switches for the hardness of the eggs 4 Suction line of the miniature dosing pump 5 miniature dosing pump 6 Pressure line of the miniature dosing pump 7 Temperature sensor 8 Heating of the evaporation tray 9 Evaporation tray 10 bimetal for heating shutdown in case of overheating 11 Preheating temperature sensor (second temperature sensor)

Claims

[1] Evaporation cooking method, preferably for eggs, in which the evaporation time of a pre-dosed defined reference quantity of water taken from a water reservoir (1) is used to determine the additional quantity of evaporation water and subsequently to add it, characterized by , that the pre-dosing of the reference water quantity and the subsequent dosing are not carried out by gravity via an actuator, but with a miniature dosing pump (5), wherein an evaporation tank (9) is preheated before the evaporation of the reference water quantity; wherein a second temperature sensor (11) or a temperature sensor (7) on the evaporation tank (9) is used for the preheating of the evaporation tank (9), the measured values ​​of which are transmitted to a control unit (2), or the temperature sensors (7, 11) are directly coupled to a temperature switch which transmits its switching signal to the control unit (2) when the target preheating temperature is reached. [2] Evaporative cooking process according to claim 1, characterized by , that a diaphragm pump is used as the miniature dosing pump (5) for dosing the amount of water, which has lockable inlet and outlet flaps, the actuation of which is only carried out by the overpressure or underpressure of the water on one side of the oscillating pump diaphragm. [3] Evaporative cooking process according to claims 1 to 2, characterized by , that an outlet opening of one of the pressure lines (6) of the miniature metering pump (5) is located above the maximum possible fill level of the water reservoir (1). [4] Evaporative cooking process according to claims 1 to 3, characterized by , that a suction line (4) of the miniature dosing pump (5) is located below the minimum fill level of the water reservoir (1). [5] Evaporative cooking method according to claims 1 to 4, wherein, in the event that harder eggs have been preset on a setting switch (3) compared to soft eggs, the defined reference water quantity to be dosed is increased. [6] Evaporative cooking process according to any one of the preceding claims, characterized by , that not all measured values ​​from the temperature sensors (7, 11) are processed directly, but that these are averaged computationally over a certain period of time using software of the control unit (2). [7] Evaporative cooking process according to claims 1 to 6, characterized by that the method is used for cooking devices that typically cook the food under increased pressure at increased temperatures.

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