DE102018102249B4 - Method for determining the temperature of water - Google Patents

Abstract

Method for determining the temperature of water when it enters a water-conducting household appliance, in particular a dishwasher (1), in which a first inlet temperature is detected while a washing program is being carried out by means of a first measuring method and in which the first inlet temperature is compared to a previous one during a rinsing of a device-side Softener (8) is compared to the second inlet temperature recorded by means of a second measuring method, whereby if a predeterminable deviation between the first and second inlet temperatures is determined, the first inlet temperature is selected programmatically as the inlet temperature for the further execution of the rinsing program.

Description

The invention relates to a method for determining the temperature of water when it enters a water-conducting household appliance, in particular a dishwasher.

Water-conducting household appliances in general and dishwashers in particular are well known from the prior art, which is why separate printed evidence is not required at this point.

A dishwasher typically has a washing compartment, which in turn provides a washing space. When used as intended, the washing container serves to hold items to be cleaned. The washing space provided by the washing container is accessible to the user via a loading opening. This can be closed in a fluid-tight manner by means of a flushing compartment door designed to be pivotable.

To load the items to be cleaned with washing liquid, the so-called washing liquor, a dishwasher has a spray device on the washing compartment side. This usually has two or three rotatable spray arms, by means of which, during normal operation, the washing liquor conveyed by a circulation pump is dispensed onto the items to be cleaned.

The dishwasher has a water connection for the introduction of fresh water from a typically public pipe network, which serves as washing liquid. As is known, this water connection can be designed either as a cold water connection or as a hot water connection. When the water connection is designed as a cold water connection, cold fresh water is introduced into the dishwasher in the intended application. With a hot water connection, preheated fresh water is supplied to the dishwasher.

In order to be able to detect during a washing program whether cold or warm fresh water is supplied via the water connection of the dishwasher, it is known that the dishwasher has a temperature sensor, which is usually arranged in a collecting pot that is fluidly connected to the washing container. Using this sensor, however, a basic distinction can only be made between the cold water connection on the one hand and the hot water connection on the other. A more precise determination of the inlet temperature of the fresh water is not possible with such an arrangement of the sensor in the collecting pot or in the rinsing container.

There are several reasons why the implication known from the prior art only enables a very imprecise determination of the inlet temperature. In order to save fresh water, dishwashers of a more modern design have a storage tank that is fluidly connected to the washing compartment and in which water from a previous washing program is temporarily stored until a subsequent washing program is carried out. The rinsing liquid flowing into the washing compartment at the start of a new washing program is therefore recruited not only from fresh water supplied, but also from water temporarily stored on the device side, which, due to its temporary storage, is at room temperature in contrast to the fresh water supplied. As a result, a water mixing temperature is established in the collecting pot, which makes it no longer possible to draw conclusions about the temperature of the fresh water supplied.

A further influence that falsifies the measurement result arises from the fact that the components of the dishwasher through which the introduced fresh water flows have a temperature that differs significantly from the temperature of the fresh water, so that there is a heat transfer between the introduced fresh water on the one hand and the dishwashing components through which it flows on the other hand . The result is a mixing temperature that is highly dependent on the amount of fresh water supplied and the temperature of the components.

Once a certain amount of fresh water has been supplied, the circulation pump is switched on under program control to circulate the fresh water introduced. As a result, the fresh water supplied is passed over the items to be washed, which also results in a heat exchange. This also leads to a falsification of the original inlet temperature of the water, so that the temperature measurement that takes place in the collecting pot is highly dependent on the temperature of the items to be washed and the washing container of the dishwasher.

The EP 2 301 407 A2 and the DE 10 2014 108 868 A1 each disclose a method for operating a dishwasher, in which the inlet temperature of the incoming water is recorded while a washing program is being carried out.

The result of the above remains that, according to the state of the art, a basic distinction between cold water connection on the one hand and hot water connection on the other hand is possible, but a more precise determination of the water inlet temperature is not permitted, since numerous influencing variables require a more precise determination of the water inlet temperature with a temperature sensor arranged in the collecting pot not allow.

Based on what has been described above, it is therefore the object of the invention to provide a method for determining the temperature of water when it enters a water-conducting household appliance, which provides more precise results with an unchanged structural design of the household appliance.

To solve this problem, the invention proposes a method for determining the temperature of water when it enters a water-conducting household appliance, in particular a dishwasher, in which a first inlet temperature is detected while a washing program is being carried out by means of a first measuring method and in which the first inlet temperature is included a second inlet temperature previously recorded during a flushing of a device-side softener using a second measuring method is compared, whereby if a predeterminable deviation between the first and second inlet temperatures is determined, the first inlet temperature is selected programmatically as the inlet temperature for the further implementation of the flushing program.

The method according to the invention uses the temperature sensor arranged in the collecting pot of a dishwasher known from the prior art. There is therefore no additional design effort involved in carrying out the method according to the invention.

According to the invention, two independent measurements are carried out using appropriate measuring methods, whereby, due to the availability and accuracy, the results resulting from the measuring methods are compared with one another via logic and, based on this, a decision is made as to which result value is used for the further implementation of a washing program. The first measurement procedure takes place during every rinsing process, i.e. while each rinsing program is being carried out.

In contrast to the first measuring method, the second measuring method only takes place when flushing a device-side softener after regeneration of the resin stored therein. Due to the larger amount of fresh water used, this measuring method delivers a significantly more precise measuring result than the first measuring method, but in contrast to the first measuring method, it is not carried out when each washing program is completed, but only when there is a regeneration of the softener Flushing of the same comes.

During the execution of a rinsing program, a first water inlet temperature, which comes from a measurement during the completed rinsing program, and a second water inlet temperature, which was determined when the device-side softener was previously flushed, are known to the system. According to the invention, it is now provided that the second measuring temperature, which is determined in principle on the basis of the rinsing of the softener, is used as the inlet temperature for carrying out the rinsing program. However, if the first measuring method results in a first inlet temperature that deviates significantly from the previously recorded second inlet temperature, the first inlet temperature is selected as the inlet temperature for further execution of the washing program. This is because the deviation of the first inlet temperature from the second inlet temperature indicates that there must have been a change in the configuration of the system or device, which is why the temperature measurement using the first measuring method deviates so significantly from the measurement result of the actually more precise second measuring method.

With the implementation of the method according to the invention, it is therefore proposed that, in order to determine the water inlet temperature, a measurement of the fresh water introduced when flushing the softener on the device side takes place. This measurement is comparatively particularly precise because flushing through the softener requires the use of a comparatively large amount of fresh water, so that any falsification of the measurement result due to device-side components is minimized. There is also no falsification by any items to be washed, as the washing chamber is loaded There is no need to flush the softener on the device side with fresh water. The water inlet temperature determined during the flushing of the softener on the device side is then selected as the water inlet temperature for all subsequent flushing processes.

For a possible correction of the selected inlet temperature, a temperature measurement is also carried out while a washing program is being carried out. If the measured temperature does not deviate significantly from the temperature previously recorded by flushing the softener, the temperature recorded as a result of flushing the softener is selected as the water inlet temperature for the program processing in the manner already described. However, if there is a significant difference between the measured temperatures, the temperature recorded while carrying out the washing program using the first measuring method is selected as the water inlet temperature.

• Gemäß dem ersten Messverfahren wird während der Durchführung eines Spülprogramms die Einlauftemperatur erfasst. Dies geschieht mittels des im Sammeltopf angeordneten Sensors.

About the measuring methods in detail:

• According to the first measuring method, the inlet temperature is recorded while a washing program is being carried out. This is done using the sensor arranged in the collecting pot.

Each rinsing program includes several rinsing program steps, including the so-called intermediate rinsing program step. Preferably, the temperature is recorded using the first measuring method during such an intermediate rinsing. This has several advantages. The water that may be present in the supply lines at the beginning of a rinsing program and which has been preheated to room temperature has already been removed by the process step preceding the intermediate rinsing, so that any falsification of the measurement result is excluded. The same applies if the dishwasher has a buffer. The water stored therein and preheated to room temperature has already been used up in a process step preceding the intermediate rinsing step, so that any resulting falsification of the measurement result is avoided.

However, despite this minimization of errors, the disadvantage can arise when measuring the temperature before intermediate rinsing that the temperature control of the device components, in particular the collecting pot, falsifies the measurement result. In order to minimize this falsification, the invention also proposes that the temperature of the water in the device is measured before and after an inlet of fresh water serving as intermediate water.

worin

m_G

Masse aller Gerätekomponenten;

c_G

spezifische Wärmekapazität der Gerätekomponenten;

m_W

Masse der Frischwassermenge (bei 2 I = 2 kg);

c_W

spezifische Wärmekapazität von Wasser.

According to this alternative and preferred method implementation for the first measurement, it is provided that in a first step the temperature of the water in the device is measured before an intermediate rinse. This temperature can be referred to as the device temperature T_G. The fresh water is then inlet for the purpose of intermediate rinsing. For this purpose, for example, a quantity of 2 liters of fresh water can be introduced into the dishwasher. Due to the supply of fresh water, a mixing temperature T_M is established with regard to the water in the device. The water inlet temperature, also known as the water connection temperature T_W, can then be calculated using the balance equation shown below: $$\text{T\_W}=(\text{T\_M}\cdot \left(\text{m\_G}\cdot \text{c\_G}+\text{m\_W}\cdot \text{c\_W}\right)-\text{m\_G}\cdot \text{c\_G}\cdot \text{T\_G})/\left(\text{m\_W}\cdot \text{c\_W}\right),$$

wherein

m_G

Mass of all device components;

c_G

specific heat capacity of the device components;

m_W

Mass of the amount of fresh water (at 2 I = 2 kg);

c_W

specific heat capacity of water.

On the basis of the previously explained calculation, the actual inlet temperature can be determined much more precisely than according to the prior art, since the method implementation according to the invention is, on the one hand, free of disturbance variables and, on the other hand, a temperature determination is carried out independently of the amount of water supplied, with the supply of only 2 I Fresh water also has the advantage that the circulation pump does not need to be operated.

According to the second measuring method, the water temperature in the collecting pot is determined at the end of the flushing of the device-side softener. This measurement methodology is essentially very accurate for two reasons. On the one hand, several liters of fresh water, for example 6 liters, are taken from the fresh water line, which with this amount of water leads to the fact that tempered water in the supply line is flushed out, and which also leads to the device components of the dishwasher in accordance with the introduced water temperature be tempered. In this respect, possible disturbances caused by water standing in the supply lines on the one hand and by device components that differ in temperature from the temperature of the supply water on the other hand are eliminated. On the other hand, the dishwasher is usually at room temperature, which means that measurement conditions are much more comparable.

Due to the amount of fresh water used, measuring using the second measuring method produces more precise measurement results than measuring using the first measuring method. Preferably, the temperature determined according to the second measuring method is also selected as the water inlet temperature in subsequent washing programs, in accordance with the following logic.

While a rinsing program is being carried out, the temperature during intermediate rinsing is determined in the manner already described and recorded as temperature T_Z. It is then checked whether the determined temperature T_Z is within a certain tolerance of the flushing temperature value T_D. The deviation between T_Z and T_D is therefore determined. If the deviation is small enough, i.e. T_Z is within a predeterminable tolerance of T_D, it can be assumed that nothing significant has changed in the measuring conditions and/or the device as such, and that the determined deviation results from inaccuracies and disturbances. The program therefore assumes the temperature value T_D as the water inlet temperature for the further rinsing process.

However, if the recorded temperature value of the intermediate rinsing T_Z is outside the predeterminable tolerance, it can be assumed that environmental conditions and/or device properties have changed since the last rinsing process, so that T_Z is assumed as the water inlet temperature for the further execution of the rinsing program.

• Mittels der erfindungsgemäßen Verfahrensdurchführung ist es in Abkehr zum Stand der Technik nicht nur möglich, zwischen Warmwasseranschluss und Kaltwasseranschluss zu unterscheiden. Es kann vielmehr die tatsächlich anstehende Wassereinlauftemperatur vergleichsweise exakt bestimmt werden.

Carrying out the method according to the invention allows a more precise determination of the water inlet temperature with an unchanged structural design of the dishwasher, which essentially brings with it the following advantages:

• By carrying out the method according to the invention, in contrast to the prior art, it is not only possible to distinguish between hot water connection and cold water connection. Rather, the actual water inlet temperature can be determined comparatively precisely.

Carrying out the method according to the invention makes it possible, in particular, to minimize misinterpretations due to standing water in supply lines. The distortion of the measurement due to different amounts of water during the fresh water inlet is also minimized. And falsification of the measurement results by starting the circulation pump while the water is being introduced is also excluded.

The more precise determination of the water inlet temperature is particularly advantageous in that a programmatic adjustment of the washing program to be carried out can be made, especially with regard to the program running time calculation. Furthermore, it is possible to check the water inlet temperature with a view to an actually desired water inlet temperature, which is particularly advantageous in the case of a hot water connection, since the implementation of the method according to the invention allows an error message to be issued in the event that the actually expected hot water temperature is actually not reached. If the water temperature is too high, the dishwasher can also be switched off automatically with an error message being issued at the same time in order to avoid unwanted damage to the device due to fresh water that is too hot. From an energetic point of view, the implementation of the method according to the invention is further advantageous in that the filling and/or emptying of an intermediate storage tank for water as provided by the program can be further optimized depending on the temperatures determined using the method according to the invention.

• 1 in schematischer Darstellung eine Geschirrspülmaschine;
• 2 in einem schematischen Diagramm eine Durchführung des ersten Messverfahrens nach der Erfindung;
• 3 in einem schematischen Diagramm eine Durchführung des zweiten Messverfahrens nach der Erfindung; und
• 4 in einem schematischen Blockdiagramm die nach der erfindungsgemäßen Verfahrensdurchführung vorgesehene Logik.

Further features and advantages of the invention result from the following description based on the figures. Show it

• 1 a schematic representation of a dishwasher;
• 2 in a schematic diagram an implementation of the first measuring method according to the invention;
• 3 in a schematic diagram an implementation of the second measuring method according to the invention; and
• 4 in a schematic block diagram the logic provided for carrying out the method according to the invention.

1 shows a water-conducting household appliance in the form of a dishwasher 1 in a purely schematic representation.

The dishwasher 1 has an outer housing 2. When fully assembled, the outer housing 2 accommodates a washing container 3, which in turn provides a washing compartment 4. When used as intended, the washing container 3 serves to hold items to be cleaned, for which purpose washing baskets are typically provided, which are located for better clarity 1 are not shown.

The washing chamber 4 provided by the washing container 3 is accessible via a loading opening 5. This can be closed in a fluid-tight manner by means of a washing compartment door 6 which is pivotably arranged on the outer housing 2.

To apply washing liquid, the so-called washing liquor, to the items to be cleaned, there are 3 in. inside the washing container 1 Spray arms, not shown, are arranged.

The washing container 3 opens out in relation to the plane of the drawing 1 into a collecting pot 7 on the underside. In terms of flow, there is an in 1 For better clarity, the circulation pump, which is also not shown, is connected.

To introduce fresh water into the dishwasher 1, it has a water connection 10. In terms of flow, this is connected to a softener 8 on the device side via a pipeline 11. The softener 8 in turn is in fluid communication with the collecting pot 7 via a pipeline 9. In the case of water introduction, fresh water passes through the pipe 11 into the softener 8 via the water connection 10 and from there via the pipe 9 into the collecting pot 7. In normal operation The water in the collecting pot 7 is distributed to the spray arms arranged in the washing container 3 using the circulation pump.

For the purpose of measuring temperature, a temperature sensor 12 is provided, which is typically arranged in the collecting pot 7, as also shown in 1 is shown. As an alternative to the arrangement in the collecting pot, the temperature sensor can also be provided at other locations, for example in one of the pipes 9 or 11 or in the circulation pump, not shown.

The method implementation proposed by the invention results from the schematic block diagrams according to 2 , 3 and 4 .

After carrying out the method according to the invention, two measuring methods are carried out, namely a first measuring method for detecting a first inlet temperature and a second measuring method for detecting a second inlet temperature. The first measurement method is in 2 shown and 3 shows the second measuring method.

2 With reference to the first measuring method at 101, the start of a washing program can be seen. After the washing program has started, the temperature of the water in the collecting pot 7 is measured at 102 and recorded as the device temperature T_G. Step 102 preferably takes place immediately before the intermediate rinsing program section, ie after completion of the first rinsing program section, the cleaning program section.

Fresh water then flows in at 103 via the water connection 10 for the purpose of intermediate rinsing. The amount of fresh water supplied for the purpose of intermediate rinsing is recorded at 104.

In order to be able to carry out a second temperature measurement as accurately as possible, a minimum amount of fresh water must be introduced for the purpose of intermediate rinsing. It is therefore checked at 105 whether the minimum amount of fresh water to be introduced has already been reached or not. According to arrow 106, the supply of fresh water is maintained and checked with regard to the quantity supplied until the required minimum quantity is introduced into the dishwasher 1.

The temperature of the water located in the collecting pot 7 is then measured at 108 according to arrow 107, the temperature being the mixing temperature T_M.

worin

m_G

Masse aller Gerätekomponenten;

c_G

spezifische Wärmekapazität der Gerätekomponenten;

m_W

Masse der Frischwassermenge (bei 2 I = 2 kg);

c_W

spezifische Wärmekapazität von Wasser.

The water connection temperature, i.e. the inlet temperature of the fresh water T_W, can then be calculated at 109 from the measured temperatures T_G and T_M, according to the following formula: $$\text{T\_W}=(\text{T\_M}\cdot \left(\text{m\_G}\cdot \text{c\_G}+\text{m\_W}\cdot \text{c\_W}\right)-\text{m\_G}\cdot \text{c\_G}\cdot \text{T\_G})/\left(\text{m\_W}\cdot \text{c\_W}\right),$$

wherein

m_G

Mass of all device components;

c_G

specific heat capacity of the device components;

m_W

Mass of the amount of fresh water (at 2 I = 2 kg);

c_W

specific heat capacity of water.

At 110, the implementation of the first measurement procedure is completed.

The second measuring method according to the method according to the invention is in 3 shown. This is not carried out during every flushing program, but only when the softener 8 is flushed after it has been regenerated.

According to 3 The flushing of the softener 8 starts at 201. The amount of fresh water supplied is recorded at 202. Typically, the softener is flushed with a minimum amount of water, for example 6 l. This flushing amount of water is necessary to achieve proper flushing of the softener in order to remove any salt residues.

At 203 it is checked whether the amount of fresh water supplied is greater than or equal to the required flushing amount. As long as this is not the case, the fresh water supply is maintained according to arrow 204.

As soon as fresh water has been introduced in accordance with the required flushing quantity, the fresh water supply is stopped and the next process step 206 is initiated according to arrow 205.

At 206, the temperature of the water in the collecting pot 7 is measured and recorded as the flushing temperature T_D. The recorded temperature T_D represents a very precise measurement variable, since any disturbance variables are essentially completely eliminated due to the amount of fresh water introduced.

At 207 the second measuring procedure is completed.

As soon as the inlet temperature during intermediate rinsing T_Z is recorded while carrying out a rinsing program according to the first measuring method, there are two inlet temperatures in terms of the program, namely the temperature T_Z on the one hand and the temperature T_D previously determined during a rinsing. It is now carried out according to the invention by means of the in 4 purely schematically represented logic decides at which of these two temperatures the further washing program is continued.

According to 4 The logic begins at 301. According to 302, the temperature T_Z and according to 303 the stored connection temperature during flushing T_D are available. These are distinguished in 304 a comparison operation. It is determined whether T_Z deviates from T_D by more than a predetermined amount. This predetermined amount with which the determined deviation is compared is between 2° C and 20° C, preferably between 5° C and 15° C, in particular between 8° C and 12° C. If a higher deviation is determined, so According to 308, the temperature T_Z is selected as the actual connection temperature for the further continuation of the washing program. Otherwise, according to the arrow 305 at 307, the temperature T_D was selected as the water inlet temperature for the further programmatic processing of the rinsing process. At 309 the execution of the comparison logic is finished.

Reference symbols

1

dishwasher

2

Housing

3

Rinse container

4

Washroom

5

loading opening

6

Washroom door

7

collection pot

8th

Softener

9

pipeline

10

Water connection

11

pipeline

12

Temperature sensor

101 - 110

Procedural steps of the first measuring method

201 - 207

Procedural steps of the second measuring method

301 - 309

Procedural steps of the comparison logic

Claims (9)

Method for determining the temperature of water when it enters a water-conducting household appliance, in particular a dishwasher (1), in which a first inlet temperature is detected while a washing program is being carried out by means of a first measuring method and in which the first inlet temperature is compared to a previous one during a rinsing of a device-side Softener (8) is compared to the second inlet temperature recorded by means of a second measuring method, whereby if a predeterminable deviation between the first and second inlet temperatures is determined, the first inlet temperature is selected programmatically as the inlet temperature for the further execution of the rinsing program. Procedure according to Claim 1 , characterized in that if a predeterminable deviation between the first and second inlet temperatures is not determined, the second inlet temperature is selected programmatically as the inlet temperature for further execution of the washing program. Procedure according to Claim 1 or 2 , characterized in that the temperature of the water in the device is measured after an inlet of fresh water serving as intermediate rinsing water. Procedure according to Claim 3 , characterized in that the measured temperature is selected as the first inlet temperature. Procedure according to Claim 1 or 2 , characterized in that the temperature of the water in the device is measured before and after an inlet of fresh water serving as intermediate water. Procedure according to Claim 5 , characterized in that an average temperature is calculated using the two measured temperatures, which is selected as the first inlet temperature. Method according to one of the preceding claims, characterized in that the temperature of the water in the device is measured after the softener (8) on the device side has been flushed with fresh water. Procedure according to Claim 7 , characterized in that the measured temperature is selected as the second inlet temperature. Method according to one of the preceding claims, characterized in that the amount of the predeterminable deviation of the first from the second inlet temperature is between 5° C and 15° C, preferably about 10° C.

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