ES2400151T3 - Procedure for the detection of a modification of the thermal capacity conditioned by the load of a water circulation appliance - Google Patents

Abstract

Procedure for the detection of the modification of the thermal capacity conditioned by the load of a water circulation appliance, in particular of a dishwasher, for the optimization of a dried process, characterized by the detection of a temperature curve during the cooling of the alavar items

Description

Procedure for the detection of a modification of the thermal capacity conditioned by the load of a water circulation appliance

The invention relates to a process according to the preamble of claim 1 of the patent.

In water circulation appliances, such as a dishwasher, the thermal behavior is modified depending on the quantity and type of the items to be washed, that is, that the items to be washed introduce a change in the thermal capacity, with the as a consequence of prolonging or shortening, for example, the duration of cooling and drying processes.

From WO 2004/047808 A1, a method for detecting the amount of dishes in the dishwasher's washing tank is known, in which both the operating data of the motor of a circulation pump and also the detection of the called heating rise in the dishwasher at least in a prewash phase and in a heating phase, the actual values detected are compared with theoretical values deposited and from it the amount of dishes found in the washing tank is derived . The washing program can then be adapted to the set amount of drawer. This procedure requires a high cost of control and regulation, since for the comparison of the theoretical values and the actual values a plurality of curve scenarios and measurement data must be deposited in a program control apparatus and must be compared with the values detected. In addition, the heating power of a dishwasher depends on the voltage of the power grid available at the site, so that the deviations of the voltage from the power grid available at the site can falsify the measurement result.

In the procedure of US 6,622,754 B1 for the detection of the amount of dishwasher load of a dishwasher a first temperature is detected by means of a temperature sensor, which is adjusted for a first load of water added after spraying and temperature compensation of the dishes. This first load is then pumped from the dishwasher wash tank. A second load of water is then added to the washing tank and its temperature is detected by means of the temperature sensor before this water is brought into contact with the dishes and heat is transmitted over the dishes. Only then is the second load of water sprayed on the dishes.

Finally, a third temperature is determined, which has the second water load after spraying and heating the dishes. The weight of the dishes can be calculated from the three temperature values detected individually.

The purpose of the invention is to prepare an improved procedure.

The solution of the purpose of the invention is based on a procedure for the detection of the modification of the thermal capacity conditioned by the load of a water circulation appliance, in particular of a dishwasher, for the optimization of a drying process.

According to the invention, it is provided that a temperature curve is recorded during cooling of the items to be washed. For example, during the main cleaning process you can measure the temperature of the wash water that needs to be cooled, which is in temperature equilibrium with the items to be washed. Since a high load is cooled more slowly than a reduced load, the detection of the wash water temperature curve can be used as a measure for the load. It can be detected in a simple way from a technical point of view through a temperature sensor, because the sensor can be integrated without much technical expense in the washing circuit. Alternatively or additionally, the temperature curve can be detected on a condensing surface, for example on the inner side of a door or on the outer surface of a water reservoir that serves as a reservoir reservoir, which serves for the intermediate storage of water and / or wash water. Favorably, in both variants, pairs of temperature values are used to determine the temperature curve in two different places on the machine. A first value can be determined in an area in front of the items to be washed, and then a second value. Therefore, a temperature difference can be detected, for example, in the bleach to be washed from values before and after contact with the items to be washed. From the modification of the difference, the modification of the thermal capacity can be determined through the items to be washed. Conveniently, the correlation of the temperature curve and thermal capacity is also applied for the detection of a temperature on the condensation surface.

In another embodiment of the invention, it is provided that the temperature curve is detected after a process of mixing wash water with fresh water, that is, that the modification of the thermal capacity through the load is determined by calorimetric means by measuring a temperature of the mixture from one of the two temperature values in the case of a change or at least partial change of the wash water. This can be done, for example, during the cleaning stage or during an intermediate washing process. At the end of a first stage of cleaning with hot water it can be discharged by total or partial pumping and fresh water can be added to the washing chamber. The fresh water is heated through contact with the items to be washed by customers and, if necessary, through mixing with hot residual water from the cleaning process. Omitting the temperature of the items to be washed before feeding fresh water, from the temperature and the amount of fresh water fed, if necessary from the amount and temperature of the fresh water that remains from the process The thermal capacity can be deduced from the adjusted temperature and the temperature of the adjusted mixture by calorimetric calculation. These data can also be easily deduced from the technical point of view - in certain circumstances with means already present, that is, with reduced technical expense.

Such a procedure would not be comfortable. In an advantageous configuration of the invention, a time dependence of a temperature representative of the temperature of the articles themselves to be washed and / or the time dependence of a temperature representative of the temperature of a condensing surface will be detected. The temperature dependence of the items to be washed or the condensation surface must be understood as the temperature curve. The moisture of the air is deposited on the condensation surface in the washing space during cooling during a drying process. In particular, the determination of the temperature on the condensation surface offers a possibility of detection, on the one hand, simple and, on the other hand, independent of the bleach and the circulation pump or its power data. Therefore, the invention takes advantage of the recognition that the temperature curve of the items to be washed or of their modification glove for a certain period of time is directly correlated with the thermal capacity and with the temperature of the items to be washed. This results in a simple calculation method from the technical point of view to indirectly determine a magnitude that is difficult to calculate in itself of the thermal capacity or to be able to estimate it in strict limits.

In the aforementioned embodiments, a setting function describing the time dependence of the temperature during cooling or the mixing can be adapted to the time dependence detected during the cooling or the mixture, presenting the adjustment function the thermal capacity of the items to be washed as an adjustment parameter. Also in this way, the thermal capacity of the items to be washed can be determined in a technically simple manner as a measure for loading.

In addition, it may preferably be provided to detect, in addition to the temperature curve during a cooling phase and / or a temperature of the mixture, the temperature curve during a heating phase of the wash water, in particular the water of lava in circulation, to raise accuracy in this way through the combination of these measurements.

In addition, a water circulation appliance, in particular a dishwasher, belongs to the invention, which has at least means for detecting the storage capacity of thermal energy conditioned by the load. According to the invention, the water circulation appliance has means, with which a temperature curve is detected during cooling of the items to be washed. The determination of the current load is done automatically, that is, without entry through a user. This simplifies the operation of the dishwasher to a considerable extent.

According to the invention, the load can be detected indirectly through a determination of the thermal capacity of the items to be washed. For the determination of the thermal capacity, the dishwasher may comprise a temperature sensor for the detection of a temperature representative of the temperature of the items to be washed as well as means for the evaluation of the detected temperature and / or its dependence on time. The temperature sensor can be arranged in a washing chamber or in the circulation circuit and comes into contact with the water that circulates during the cleaning process, which is again in heat exchange with the items to be washed. Therefore, it can be arranged in such a way that it can at least indirectly detect the temperature of the items to be washed. Additionally, a second temperature sensor may be present with corresponding evaluation means for detecting the temperature of freshly fed fresh water, not yet heated. In dishwashers, which comprise a heat accumulator, conditioned by the type of construction, the second temperature sensor may be in heat exchange with the heat accumulator. The second temperature sensor and the evaluation means make it possible to determine the thermal capacity of the load according to the last procedure described above.

The dishwasher may comprise a regulation unit, which is configured to process data from the temperature sensor (s), that is, the procedure described above or sections thereof and their variables.

The principle of the invention is explained in detail below with the help of the exemplary drawing. In the drawing:

Figure 1 shows a temperature curve in the washing space of a dishwasher.

Figure 2 shows a fragment of a temperature raven of this type for different loads.

Figure 3 shows a schematic sectional view of a first dishwasher, and

Figure 4 shows a schematic view of the section of another dishwasher.

Figure 1 shows the known work steps in a dishwasher with own heat drying. They comprise a prewash stage 2, a heating phase 4, a cleaning stage 6, an intermediate washing stage 8, a rinsing stage 10 and a drying stage 12 that terminates the work processes. In the prewashing stage 2, cold clean water (approximately 3.4 to 3.9 l) is fed and circulated for a preset period of approximately 15 minutes through a circulation pump 20 through the washing chamber 14 (see figures 3 and 4). A heating installation 56 (see Figures 3 and 4) in the hydraulic circuit heats the fresh water of the prewash stage 2 in approximately 13 to 14 minutes at an initial cleaning temperature of approximately 51 ° C. In this way, the articles to be washed 28 are also heated in the washing chamber 14. In the next cleaning stage 6, the hot washing water and provided with detergent is circulated, whereby the articles to be washed 28 are cleaned in one essential measure.

Between the cleaning stage 6 and the intermediate washing stage 8, the washing water is pumped from the cleaning chamber 14 and fresh, clean, fresh water is fed. The fresh water circulates during the intermediate washing stage 8 for a period of approximately 5 minutes and is heated in this case mainly through contact or through heat transmission from the cleaning stage 6 to the items to be washed 28 still hot and, if necessary, through a heat exchanger 38 (figure 4). For the change from the intermediate wash stage 8 to the next rinse stage 10, the intermediate wash water is pumped out of the washing chamber 14 and cold clean water is fed again.

In conventional dishwashers with own heat drying, the cold clean water fed in the rinse stage 10 is circulated for a predetermined time, fixedly adjusted, for example of approximately 15 minutes, and in this case it is heated with a predetermined fixed heating power to the initial temperature T0 for the next drying process 12, for example at about 65 ° C.

Figure 2 illustrates the time curve of the characteristic temperature or the time dependence of the temperature in the washing chamber for different loads during the rinsing stage 10 and during the drying stage 12. The central curve in Figure 2 shows the temperature curve in the washing chamber for a defined standard curve BStandard. The upper or lower curve in Figure 2 represents the temperature curve in the washing chamber, which is established with a higher load B +: = BStandard + iB or with a lower load B-: = BStandard -iB compared to the standard BStandard load. Through the heating power supply, the temperature in the washing chamber 14 is raised and, therefore, also the temperature of the items to be washed during the rinsing stage 10 is essentially proportional to the time t. The consequence of the rise in temperature less than proportional, shown in Figure 2, is loss of heat transmission, among other things, through the walls of the washing chamber 14 and through the loading door 16.

For the standard BStandard load the temperature is regulated during the heating phase in the rinsing stage 10 according to the central curve in Figure 2 except for an initial temperature B0, Standard. Immediately afterwards the drying stage begins with its own heat 12, that is, the complete evaporation of the water film on the items to be washed. If a higher or lower load has been detected, a correspondingly greater or less thermal energy input is necessary for drying with own heat. Correspondingly, the temperature is regulated during the heating phase at a higher or lower initial temperature T0

+ iT and T0 -iT, respectively for the stage of drying with own heat 12.

With the disconnection of the heating power, which is fed to the washing water in circulation during the rinsing stage 10, the drying stage 12 starts. The temperature in the washing chamber essentially develops correspondingly to a downward exponential function. . Meanwhile, a film of liquid present in the items to be washed is evaporated 28 and condensed on a condensation surface. In a moment t12, a temperature t12 is achieved as a characteristic feature, which is only modified below in a non-essential measure and marks the extent of an essentially asymptotic state. The moisture film is then evaporated completely on the items to be washed 28 and the drying process 12 can be completed. Since the scope of the instant t12 depends on the load, its detection is essential for the regulation of the drying process with respect to the energy input and the time curve.

According to the invention, the time dependence T1 (t) of a real temperature T1 in the washing chamber is detected during the cooling phase of the cleaning stage 6, that is, the temperature curve over time t . From this, the thermal capacity of the load is obtained as a measure for the actual Bist load. The time dependence T1 (t) of the temperature during the cooling phase essentially follows an exponential function at time t

In this case, Cges = C (Bist) + C (water) represents all the thermal capacity, which is detected as the sum of the thermal capacity C (Bist) of the current Bist load and the thermal capacity C (water) of the circulating water T0 is the time, at which the cooling phase begins. The thermal capacity C (water) of the washing water in circulation depends on the amount of water introduced, which is measured during the filling of the washing chamber with fresh water. The total thermal capacity Cges is determined by adapting an adjustment function to the cooling curve T1 (t) with Cges as the adjustment parameter. Finally, the modification of the thermal capacity C (Bist) through the current load Bist is calculated by subtracting the measured thermal capacity C (water) from the total thermal capacity Cseg derived from the cooling curve T1 (t ).

According to an alternative embodiment of the invention, for the determination of the modification of the thermal capacity through the load, the temperature of the mixture which is regulated in the intermediate washing step 8 is measured. For this purpose, it adapts a function to the time dependence of the temperature measured in the intermediate washing stage 8 by means of adjustment and from this the temperature of the mixture is determined, which is adjusted after the feeding of the cold clean water at the beginning of the intermediate washing stage 8 through the comparison of the temperature with the items to be washed 28 still hot from the cleaning stage 6 as an asymptotic approximation value of the temperature and time dependence in the intermediate washing stage 8 using known mathematical equations or models for mixing the calorimetric temperature.

The dishwasher shown in Figure 3 comprises a washing chamber 14, in which the items to be washed 28 are placed in a loading basket 30, a loading door 16 fixed in the washing chamber 14, a rotating spray arm 24 of the water rotatably disposed in the washing chamber 14, a circulation pump 20 arranged below a bottom wall 19 of the washing chamber 14 for the circulation of the bleach, an inlet 22a, which connects the pump circulation 20 with the rotating water spray arm 24, an outlet 22b in the bottom wall 19 of the washing chamber 14, which is connected to a suction side of the circulation pump 20, a heating device 56 in the inlet 22a for heating the circulating water, a first temperature sensor 32 and a second temperature sensor 34, a regulating unit 58 for the regulation of the working stages and devices of the dishwasher and for the output and evaluation of the measurement signals of the temperature sensors 32, 34, a connection line 48 for the supply of fresh water, an output line 52 for the discharge of the washed bleach as well as a heating installation 56 at input 22a with a control line 56a towards the regulating unit 58.

The first temperature sensor 32 is arranged in the circulation pump 20 and serves to detect the temperature T1 of the water or of the bleach in the circulation circuit. However, also in other positions in the circulation circuit, such as in the inlet 22a, in the outlet 22b or in a cavity in the back wall of the washing chamber 14 may be arranged in the vicinity of the opening of the exit 22b. The second temperature sensor 34 is arranged in contact with the wall of the inner side, that is, with the `wall of the loading door 16 which is directed towards the washing chamber 14 and serves to detect a reference temperature T2 characteristic for the temperature of a cold surface in the washing chamber 14. It can also be arranged, for example, on a control panel 18 on the loading door 16.

The temperature sensor 32 in the circulation pump 20 detects a curve of the temperature of the wash liquor over time and transmits the data to the regulator 58. The temperature of the bleach is determined, on the one hand, by the starting temperature of fresh water from the duct of the domestic installation. Since the fresh water first reaches the circulation pump 20, before it is pumped forward, the sensor 32 can detect its temperature. In the same way the heating power fed, otherwise, to fresh water is known. The energy losses through the duct 22a and the walls of the washing chamber 14 are largely constant or have only a relatively small influence. In this way, the regulating installation 58 can calculate the temperature of the bleach to be washed at the entrance in the washing chamber 14 before hitting the items to be washed 28.

Another influence on the temperature of the bleach has the temperature of the items to be washed 28, in which the bleach can be heated or cooled. In the case of multiple circulation of the bleach, for example during the heating phase 4 (see Figure 1), the bleach reaches, after each cycle from the washing chamber 14, a lower temperature than the temperature it presented in the entry 22a, because it is cooled in the items to be washed 28. Both from the difference in the temperature detected between the bleach that flows into the washing chamber 14 and the bleach leaving the washing chamber as well as from this Unlike the temperature over time, the regulating installation 48 can deduce the degree of the load of the washing chamber 14. In the case of a smaller quantity of items to be washed 28, there is a smaller thermal capacity in the chamber to wash 14, which cools the bleach less. The items to be washed 28 are therefore heated more rapidly, whereby the heating phase 4 can be shortened or the heating power 56 can be reduced. Conversely, in the case of a higher load. An extension of the heating phase 4 or an elevation of the heating power is necessary.

Alternatively or additionally, namely to improve the data base of the regulating unit 58 for the calculation of the load, a second temperature sensor 34 may be installed together or in the loading door

16. The loading door 16 represents a relatively cold condensation surface in the drying stage 12 through its own heat. The items to be washed 28 heated in the preceding rinsing stage 10 evaporate the moisture, which precipitates into the loading door 16 as a cooler condensation surface. Also the temperature curve of the condensation surface is an indication of the degree of load of the washing chamber 14. Since a larger amount of items to be washed 28 can bind a correspondingly greater amount of moisture on its surface. The condensation produced below yields a greater amount of heat to the condensation surface of the loading door 16, than a smaller load.

The second embodiment of the dishwasher shown in Figure 4 differs from the first embodiment shown in Figure 3 by a water collector 38 that serves as a temperature accumulator. The same elements of the first and second embodiments are designated with the same reference signs.

The dishwasher according to Fig. 4 comprises the connection line 48 provided with the controllable connection valve 50 for the ventilation of the heat exchanger 38 with fresh water and a connection line 40 between the exchanger 38 and the circulation pump 20 thus as a third temperature sensor 36 disposed in the water accumulator 38 for the detection of the temperature T3 of the water in the water manifold 38. The connection line 40 is opened and closed through the controllable connection valve 42. The Valve 42 is controllable through a line 42a to the regulating unit 58. When the valve 52 is closed and the valve 50 is open, the water accumulator 38 is filled with cold clean water. In the reverse position of the valves, it is filled with water from the circulation circuit which, if necessary, may be heated.

The water collector 38 is configured in the form of a tank arranged parallel to the side wall of the washing chamber 44 and rests on the side wall. The third temperature sensor 38 is arranged in contact with the wall of the water collector 38 which is directed towards the washing chamber 14. To improve the efficiency of heat drying, the water collector 38 is filled during the stage of 12 dried with cold clean water. In this way, the side wall of the washing chamber 14, which is directed towards the water collector 38 becomes a refrigerated condensation surface. The temperature sensor 36 thus fulfills, on the one hand, the same purpose as the sensor 34 in the last example described. But since it is exclusively in the clean water inlet stream of the circulation pump 20, it can detect the outlet temperature of the clean water more accurately than the temperature sensor 32. Therefore, it provides a better database for the determination of the load through the regulation unit 58.

List of reference signs

2 Pre-wash / pre-wash stage 4 Heating / heating phase 6 Cleaning / cleaning stage 8 Intermediate / intermediate wash stage 10 Rinsing / rinsing stage 12 Drying / drying stage 14 Washing chamber 16 Loading door 18 Panel control 19 Bottom plate 20 Circulation pump 20s Control line for the circulation pump 22a Inlet 22b Output 24 Rotating water spray arm 28 Items to be washed 30 Load basket 32 First temperature sensor (circulation circuit) 34 Second sensor of condensing surface temperature (eg loading door) 36 Third temperature sensor (heat exchanger) 38 Heat exchanger 40 Connection line 42 Connection valve 42s Control line for connection valve 44 Connection 48 Power line connection 52 Output duct 56 Heating device 56s Control line for heating device 58 Regulation unit

Claims (10)

one.

Procedure for the detection of the modification of the thermal capacity conditioned by the load of a water circulation appliance, in particular of a dishwasher, for the optimization of a drying process, characterized by the detection of a temperature curve during cooling of the items to be washed.

2.

Method according to claim 1, characterized in that the temperature curve of the washing water is detected, and particularly of the washing water in a circulation circuit.

3.

Method according to claim 1 or 2, characterized in that the temperature curve is detected in a condensation surface, in particular in a loading door (16).

Four.

Method according to claim 1 or 2, characterized in that the temperature curve is detected in a water collector (38).

5.

Method according to one of claims 1 to 4, characterized in that the temperature curve is detected after a process of mixing wash water with clean water, in particular after the detection of the water temperature curve of wash in the circulation circuit and / or through the detection of the temperature curve on a condensation surface, in particular in a loading door (16) or through the detection of the temperature curve in a collector of water (38).

6.

Method according to one of claims 1 to 5, characterized in that the temperature curve is detected for a predetermined period of time.

7.

Method according to one of claims 1 to 6, characterized in that the temperature curve is detected within a predetermined temperature range.

8.

Method according to one of claims 1 to 7, characterized in that the temperature curve is detected continuously or at predetermined intervals.

9.

Method according to one of claims 1 to 8, characterized in that the temperature curve is detected during a heating phase of the wash bath.

10.

Water circulation appliance, in particular dishwasher, which has at least means for the detection of the thermal energy accumulation capacity conditioned by the load, characterized by means (32, 34, 36) with which a temperature curve is detected during cooling of the items to be washed.