DE9203663U1 - Measuring and/or control device for cooking, boiling or similar processes in open or closed systems - Google Patents

Description

181 G29

Measuring and/or control device for cooking, boiling or similar processes in open or closed systems

The invention relates to a measuring and/or control device for cooking, boiling or similar processes in open or closed systems.

Both in large kitchens and in private households, conventional cooking areas and stoves are known in which, for example, a total cooking time can be preset, i.e. specified. Once the cooking time has been reached, the oven switches off automatically. In some cases, this can also be combined with a preset start time. This means that a time can be preset at which the oven switches on automatically, carries out the cooking or boiling process and switches off again automatically after the preset cooking or boiling time has elapsed. The temperature is preset separately using the usual setting controls for the hotplates.

The object of the present invention is to provide a measuring and/or control device for cooking, boiling or similar processes in open or closed systems

to create a device in which the relevant process, i.e. in particular the cooking or boiling time and the individual variables influencing the process or the cooking or boiling time, can be determined more precisely and accurately and/or the relevant information can be displayed when required. Under certain circumstances, it should also be possible to automatically switch off the cooking, boiling or similar process. The device according to the invention should be usable in particular in closed systems such as pressure cookers, i.e. so-called pressure or steam cookers.

The object is achieved according to the invention according to the features specified in claim 1. Advantageous embodiments of the invention are specified in the subclaims.

The present invention creates a considerable technical improvement. According to the invention, the cooking process of food can be simplified and monitored and controlled much more precisely and correctly.

If, for example, 1 kilogram of peas is to be cooked in a pressure cooker, a certain "key parameter" can be read out from a table depending on the food and set in the cooking time measuring device according to the invention. In addition, an altitude-dependent correction value can also be taken into account under certain circumstances, which represents a measure of the average altitude-dependent pressure differences.

The cooking and boiling process is then carried out according to this conductivity.

The cooking temperature, the absolute pressure during cooking as well as

the total cooking time under these conditions is crucial. Since cooking always involves using water, wine, cream or other additives, i.e. on a water basis, increasingly higher pressure is generated by evaporation, particularly in closed systems. This increased pressure also ultimately increases the temperature to above the boiling point at ambient temperature, which speeds up the entire cooking process.

According to the measuring and control device according to the invention, the corresponding values can be processed in such a way that the device, for example, always displays the remaining cooking time or emits a signal when the total cooking time has been reached, which - as stated - depends not only on the time alone, but also on the absolute pressure and the preset temperature.

In a preferred embodiment, not only the pressure but also the temperature can be measured simultaneously using a single piezoresistive pressure sensor. This is possible by tapping the bridge voltage, which is also a measure of the temperature.

In addition, the humidity can also be measured using an additional humidity sensor. Particularly when cooking or boiling in open systems, i.e. not in a pressure cooker, the measurement of the moisture content in the air, i.e. the strength of the steam formation, can be crucial for the cooking or boiling process.

In a preferred embodiment, the display device can also be designed as a switch-off device for the cooking appliance or the cooking area or can include such a switch-off option.

In a further development of the invention, the display device always shows the current temperature, such as

The current absolute pressure in the cooking appliance is also displayed during the cooking process.

In a closed system, the known vapor pressure curve applies. Such a vapor pressure curve as a function of the temperature for salt-free water could be stored in the device according to the invention. By measuring the actual temperature-dependent vapor pressure curve and a possible deviation from the pre-stored vapor pressure curve for different temperature values for salt-free water, a conclusion could then be drawn about the salt content of the aqueous solution. In other words, the device according to the invention can also determine the salt content in the water, which is and can be extremely interesting, especially when preparing food.

Finally, the pressure increase can also be monitored by constantly measuring the pressure and, if necessary, a pressure valve provided on a pressure cooker can be automatically or manually adjusted so that a desired maximum pressure is not exceeded.

In a particularly preferred embodiment, a trigger or threshold circuit is provided. This is used to initiate the cooking process.

Here, an individual or manufacturer-defined temperature threshold can be preset, whereby the calculation of the actual cooking time only begins once this trigger temperature is exceeded.

Finally, even after the cooking process has been completed, the actual, i.e. effective, conductivity can still be displayed on the display, which may differ slightly from the preset value.

Finally, in a particularly preferred embodiment

In an embodiment of the invention, the input point can be designed in such a way that not only one control parameter important for the absolute pressure, temperature and cooking time, but also, if necessary, several individual data are preset, based on which the actual cooking process is then monitored and/or controlled.

The device according to the invention can therefore achieve a wide range of advantages. Above all, by entering a corresponding control parameter, an "integral" value is specified for the course of the process, in particular the cooking or boiling process. If, for example, two essentially identical cooking processes for the same foodstuffs are compared with each other, whereby in one case - because the cooking area was set to a different temperature - only a low temperature and thus a lower pressure in the pressure cooker is achieved, this has the result that the device according to the invention determines a longer cooking time for the cooking pot whose temperature and steam pressure are lower. In both cases, the food in question is cooked optimally.

Further advantages, details and features of the invention will become apparent from the following description taken with reference to the drawings.

explained embodiment. In detail:

Figure 1: a schematic vertical sectional view through a pressure cooking device with a schematically indicated integrated, i.e. built-in, cooking time measuring device according to the invention;

Figure 2: a schematic representation of the display device of the cooking time according to the invention

Measuring device before starting the cooking process;

Figure 3: a schematic plan view of the display device of the inventive

Cooking time measuring device during the cooking process.

Figure 1 shows a schematic vertical cross-sectional view of a pressure cooker 1, which in the embodiment consists of a cooking pot 3 and a lid 5, which, as with known pressure cookers, can be placed firmly and airtight on the cooking pot 3. Corresponding pressure relief or safety valves, also for releasing and reducing the excess pressure in the cooking device 1 after the cooking process has ended, are provided at a suitable location, for example in the lid 5. Such measures are known and are not shown in more detail in the embodiment below.

The overpressure cooking device 1 in Figure 1 is provided with a cooking time measuring device 7, which comprises a display device 9 and a sensor device 11. The sensor device 11 is connected to the interior of the cooking pot in a suitable manner in order to measure both the pressure prevailing in the cooking pot, i.e. the absolute pressure, and the temperature. In the embodiment shown, the cooking time measuring device 7 is mounted on the lid 5, namely via a mounting tube 13, via which the housing of the cooking time measuring device with the corresponding circuits discussed below and the display device 9 is mounted and held on the outside of the lid 5. At the same time, a connection is created via the mounting tube 13 from the sensor device 11 on the inside of the cooking pot to the display device 9 located outside the cooking pot. The corresponding electrical connecting lines 14 can also be accommodated here.

Of course, the cooking time measuring device 7 can also be pre-assembled elsewhere in the cooking appliance 1, for example it can also be completely integrated into the lid, with a corresponding display device only being housed on the top of the lid, which can even be flush with the top of the lid, for example.

The absolute pressure, the temperature and the time under these conditions are decisive for a cooking process. The cooking time measuring device therefore comprises the sensor device 11 mentioned, which comprises an absolute pressure sensor 11' and a temperature sensor 11". Furthermore, a time measuring device 15, an electronic evaluation stage 17 with a signal processor 17' which converts the electrical values and a microprocessor 17" which processes the correspondingly converted measurement data and controls the display device 9 are also provided.

The mentioned absolute pressure sensor 11' and the temperature sensor 11" may be two separate sensors.

However, it is also possible, for example, to use a so-called piezoresistive pressure sensor as the absolute pressure sensor 11', from which not only a pressure-dependent measurement signal but also a temperature-dependent bridge voltage signal can be tapped. This means that not only the pressure but also the temperature can be measured at the same time using a single sensor.

0 In this respect, reference is also made to the brochure "SENSO-BRAIN - The world's first IC sensor signal processor, Keller AG für Druckmeßtechnik" and the publication PCT/WO89/08819. The electronic evaluation devices described in these documents provide an 8-bit resolution for the sensor, which corresponds to a measurement accuracy for the temperature of 0.5O, which is generally more than sufficient for such processes. If required, a higher resolution can be provided.

Finally, a further humidity sensor 12 can optionally be provided in order to measure the humidity content in the air, i.e. the degree of steam formation - particularly in open systems that do not work with a pressure cooker. These are also potentially decisive variables for the cooking and boiling process. Such a humidity sensor 12 could be connected as a second sensor to the evaluation electronics described in the two previous publications mentioned above, without this requiring an increase in the electronic effort for the evaluation of these measurement signals.

The evaluation stage 17 creates an integral value from the factors "cooking time", "temperature" and "pressure".

The further operation and functionality will be explained in more detail below using Figures 2 and 3.

If, for example, 1 kilogram of peas is to be cooked in a pressure cooker 1, a specific key parameter that is food-dependent can be taken from a corresponding table and overview provided to the user and consumer. For example, when cooking 3 kilograms of peas, a key parameter of "40" per kilogram can be taken. The different weight quantities have no relevant influence on the cooking process. If the temperature rise curve is lower or the steam pressure build-up is lower or increases more slowly due to larger weight quantities, the device described would automatically determine and regulate a corresponding extension of the cooking process in order to always cook the food in question evenly. At most, for example, "additional figures ¹¹ " could be taken into account for foods that can be put into the pot in different sizes.

If, for example, small potatoes are to be cooked which have a conductivity parameter value of "40", in the case of cooking particularly large potatoes, an additional factor of "3" could be taken into account, so that in this case the total conductivity number may be "43". By pressing a further button 19, the cooking time measuring device 7 and thus also the display device 9 can be switched on automatically when the button 19 is touched. The functional mechanism can, for example, be such that a preset initial conductivity parameter, for example corresponding to the number "30", is automatically displayed in the middle display field, which is programmed as the initial preset value. The button 19 can, for example, be designed as a toggle button, whereby a tilt to the right starts a slow "up" of the preset conductivity from the number "30". Conversely, a tilt of the button 19 to the left a slow "counting down" to lower control parameters. In this case, the rocker button 19 would have to be pressed to the right until the control parameter display number "43" appears in the middle display field. If necessary, an altitude-dependent correction value can also be added. This is because the absolute pressure when cooking, for example, at the altitude of Munich is always somewhat lower than the absolute pressure at sea level. However, as a rule, such a location- and altitude-dependent correction is only of very minor importance or not necessary at all, since at a higher altitude with a somewhat lower absolute pressure the "integral formation" is always carried out by the device in such a way that the required cooking time may be slightly longer.

Based on this set guide number, the aforementioned integral formation of the values "temperature", "absolute pressure" and "cooking time under these conditions" is used to determine the

Measurement is carried out and the actual cooking time is determined. If for some reason the heating is comparatively lower due to a lower setting on the hotplate, the control parameter will then result in an overall longer cooking time. By increasing the pressure and temperature, this can in turn lead to a comparatively shorter cooking time.

The measurement can be carried out continuously or at discrete time intervals. It is sufficient to capture, measure and process the measurement signals for the temperature and pressure inside the cooking appliance every 30 seconds, for example.

The pressure prevailing inside the cooking appliance, which is measured by the absolute pressure sensor 11', is always shown in the upper display field.

Before the cooking process begins, no values are shown on the additional display fields provided at the bottom left and bottom right; in this case, only the number " ¹¹ OO" is shown.

Once the key parameter number determined from the table has been set as explained according to the food to be cooked and the amount of food, the cooking process can begin.

After the cooking area (not shown in detail) has slowly heated up, the interior of the pressure cooking device and the food inside it also heat up, with the pressure increasing and building up at the same time due to the airtight seal.

5 Since the cooking time measuring device 7 preferably also includes a threshold value, i.e. trigger circuit for a pre-settable or pre-set temperature value, the measurement of the cooking time is only started when the

exceeding this preset temperature. For example, a temperature value of 500C can be set here. Exceeding a trigger pressure inside the pressure cooking device 1 can also serve as a threshold value or trigger value for starting the measurement of the cooking process.

When the preset starting temperature or pressure is reached and the cooking process begins, the middle display shows the temperature in oc. The cooking time in minutes is shown at the bottom left and the remaining cooking time until the cooking process is completed is shown in the display field at the bottom right, as shown schematically in Figure 2.

Since the pressure is measured and displayed during the entire cooking process, if a certain maximum pressure is to be maintained, a manually operated pressure relief valve can be set so that a certain pressure is not exceeded. This can be easily checked visually. Of course, automatically controlled pressure relief valves are also conceivable here, although such complex switching measures are probably only conceivable in large kitchens or in the industrial production of canned goods, etc.

Finally, a further improvement is also conceivable by using at least one additional temperature sensor, which, for example, reaches as far as the bottom area 0 of the pot. This allows an even more precise temperature measurement, especially in heavily filled pots, since a temperature gradient, i.e. a temperature drop, can build up in the cooking pot itself, so that by measuring the temperature at different points, a better measurement value can be recorded.

Finally, after completion of the cooking process, an acoustic or other signal may indicate the completion of the

A trigger signal indicating the end of the cooking process can be generated. In some circumstances, the cooking time measuring device can alternatively and additionally also be connected to the heating device of the cooking area in order to switch it off automatically.

The circuit can be designed in such a way that after the cooking process has been completed and the excess pressure has been released and the temperature has been reduced, the effective control parameter value is then displayed on the middle display field. The reduction in the excess pressure to the normal ambient pressure can always be read on the upper display field. In the example shown, the ambient pressure is 965 bar.

The device switches off again by pressing button 19 or a separate on/off button for a longer period of time. A safety circuit can ensure that - if the device is not switched off - it switches off automatically after one hour.

Finally, as mentioned, the sensor device 11 can also include another moisture sensor 12 if required. This can be used to measure the moisture content in both closed and open systems, i.e. in preheated cooking pots or in cooking pots with a lid that is only loosely placed on top. In such a refined design, this measurement result can also be taken into account in a suitable manner in order to determine the total cooking time actually required even more precisely. This is because the moisture can certainly have an - albeit subordinate - significance for the cooking process.

Finally, the pressures determined during the cooking and boiling process 5 and the associated temperature values, i.e. the pressure-steam diagram, can be determined and compared with the steam pressure-temperature-pressure curve known for salt-free water. The deviation can be used to calculate

The device can determine the salt content in the aqueous liquid and, if necessary, also display it on the display device. This can be particularly interesting when cooking food, especially in large kitchens or when producing canned goods, where certain salt content values must be maintained as precisely as possible.

The above-mentioned device is particularly suitable for so-called pressure cookers. But it also offers advantages for conventional cooking pots, since here too the cooking or boiling process can be automatically monitored and controlled by measuring the temperature profile, measuring the absolute pressure (which is generally constant and only dependent on the height) and in particular by measuring the humidity. But the present invention can also be used for similar processes, for example in the sterilization of cutlery in medical practices, etc., whereby the corresponding device records the sterilization time more precisely based on the actually measured pressure, temperature, etc. and the sterilization itself can be carried out in a shorter time.

Claims (20)

181 G 29 Measuring and/or control device for cooking, boiling or similar processes in open or closed systems Claims: 1. Measuring and/or control device for cooking, boiling or similar processes in open or closed systems, in particular for cooking devices including pressure cooking devices and cooking pots, which is installed or attached in or on the cooking device (1) or can be installed or attached, with a pressure sensor (H') and a temperature sensor (H") for measuring the temperature and pressure in the cooking device (1), as well as a time measuring device (15) for measuring the time during the cooking process and with an evaluation circuit (17) and a display device (9) and an input or setting device for setting at least one control parameter for the desired cooking process, wherein the evaluation circuit (17) processes the measurement data supplied by the time measuring device (15), the pressure sensor (H') and the temperature sensor (H") and uses this to generate an evaluation signal about the current status of the total cooking time and/or the remaining cooking time and/or the achievement of the necessary 15
Total cooking time can be generated. 2. Device according to claim 1, characterized in that the evaluation circuit (17) forms an integral value from the measurement data for the temperature prevailing in the cooking appliance (1), the pressure and the time elapsed under these conditions. 3. Cooking time measuring device according to claim 1 or 2, characterized in that the control parameter is a food- and food quantity-dependent presettable conductance influencing the entire cooking time. 4. Device according to one of claims 1 to 3, characterized in that a temperature-dependent trigger or threshold circuit (21) is additionally provided, which only starts the cooking time measurement when a presettable or preset trigger value for the temperature is exceeded or reached. 5. Device according to one of claims 1 to 4, characterized in that a presettable pressure-dependent trigger or threshold circuit (21) is additionally provided, which only starts the cooking time measurement when a presettable or preset trigger value for the pressure is exceeded or reached. 6. Device according to one of claims 1 to 5, characterized in that an absolute pressure sensor is provided as the pressure sensor (H'). 7. Device according to one of claims 1 to 6, characterized in that only a single sensor is provided for measuring both the pressure and the temperature, namely a piezoresistive pressure sensor, the tapped bridge voltage of which is a measure of the temperature. 8. Device according to one of claims 1 to 7, characterized in that the sensor device (11) further comprises a humidity sensor (12) for measuring the humidity. 9. Device according to one of claims 1 to 8, characterized in that the evaluation circuit (17) comprises a signal processor (17') for converting the electrical values into corresponding control or evaluation signals. 10. Device according to one of claims 1 to 9, characterized in that the evaluation circuit (17) comprises a microprocessor (17") for processing the measurement signals or the converted measurement signals for controlling the display device (9). 11. Device according to one of claims 1 to 10, characterized in that the vapor pressure-temperature curve or data corresponding thereto for salt-free water is stored in the evaluation circuit (17) and that the vapor pressure reduction and thus the salt content of the aqueous solution can be determined from the deviation from the vapor pressure-temperature curve actually determined during the cooking process or from the data corresponding thereto. 12. Device according to one of claims 1 to 11, characterized in that the presettable control parameter value can be displayed in the display device (9). 13. Device according to one of claims 1 to 12, characterized in that after completion of the cooking process, the effective control parameter value can be displayed on the display device (9). 14. Device according to one of claims 1 to 13, characterized in that the pressure prevailing and measured in the cooking appliance interior is displayed on the display device (9) before, during and after completion of the cooking process. 17
is showable. 15. Device according to one of claims 1 to 14, characterized in that the temperature prevailing in the interior of the cooking appliance can be displayed on the display device (9) at least during the cooking process. 16. Device according to claim 15, characterized in that the temperature prevailing in the interior of the cooking appliance which can be displayed on the display device (9) can be displayed at least after a temperature threshold value has been exceeded. 17. Device according to one of claims 1 to 16, characterized in that it is or can be installed in or on the lid (5) of the cooking appliance (1). 18. Device according to one of claims 1 to 15, characterized in that the pressure and the temperature occur in discrete steps at intervals of time. 19. Device according to claim 18, characterized in that the measured value acquisition takes place at time intervals of 1 second to 60 seconds, preferably every 20 seconds to 40 seconds, in particular approximately every 30 seconds. 20. Device according to one of claims 1 to 17, characterized in that the measured value acquisition takes place continuously.