DE2950928B1 - Circuit arrangement for the moisture and temperature-dependent control of a washing and drying machine - Google Patents

Description

The invention is based on a circuit arrangement for humidity and temperature-dependent Control of an electric heater; facilities equipped washing machines and dryers in Dependence on in the washing and drying room and / or in the exhaust air of the drying device temperature and humidity sensors arranged in the leading duct.

There are individual solutions for measuring temperature or humidity in washing machines or tumble dryers known (DE-OS 2037 383, DE-AS 51 277). These known solutions are also available for each Has been used when combined washing and drying machines, hereinafter referred to as washer-dryers for short called, be equipped in terms of control

J (I

had to.

In addition to the not yet generally accepted principle of temperature detection by means of temperature-dependent Resistors, it is known to detect the temperature of the detergent solution by bimetal switches that Tried and tested are produced in large numbers and are therefore cheap. As with washer-dryers now other temperatures can also be recorded, in some cases at other locations within the machine it is common to use additional bimetal switches. Occasionally they are used for this purpose as well different types of temperature sensors used A control depending on the humidity of the to Drying laundry has never been used in washer-dryers, because the ones used for this purpose Construction principles of the further effort to measure the laundry moisture through special moisture detection and processing agent appeared to be too high. Instead, you always have to deal with a Time control is sufficient for the disadvantageous drying results that are only useful with a certain composition and initial residual moisture of the laundry item can deliver. At most, the time control was combined with a temperature measurement in the Way applied that when the temperature rises to 65 ° C or above, namely when the temperature decreases Remaining fire to values around 10%, the time control for the duration of an after-drying phase is started. But this control is also different Too imprecise batch of laundry, on the other hand, requires too much attention from the operator in the With regard to the assignment of the duration of the drying time to the type of laundry item and is also relatively complex.

The invention is based on the object of developing a circuit arrangement that is known Control principles combined in such a way that measuring devices already in use are used can so that the reluctance of the designer to completely revise the already mass-produced Washer-dryer is not used excessively. In addition, the circuit arrangement should have a time control completely dispense with the drying process.

According to the invention, this object is achieved in that each sensor or each group of sensors the each input is assigned its own comparator with step characteristics of the output signal whose other input can be loaded with fixed or adjustable comparison variables, and that the outputs of the comparators via a mixer with a switching device for the heating devices are connected.

To implement the circuit arrangement according to the invention, the designer can already rely on Occasionally common temperature sensors with temperature-dependent resistances as well as on already Use common sensing electrodes within the laundry room to scan the laundry moisture. A sound system for the existing program switches and program switching devices with the Inputs and outputs of the circuit arrangement according to the invention mean compared to the previous one State a simplification. When designing modern household appliances, it is obvious which Circuit arrangement according to the invention, if necessary, subdivided in groups from individual modules such as Transistors, operational amplifiers in list, and the like, or from the internal circuitry of a part

of a microprocessor. To record the physical quantities "temperature" on the one hand and "degree of humidity" on the other hand a single sensor or one for all values a group of sensors suitable for the physical size. The output signals of the comparators can thus act in the simplest way on the rest of the electrical equipment of the washer-dryer, as will be explained in the following exemplary embodiment.

In a particularly advantageous development of the circuit arrangement according to the invention are for all temperature-dependent controlled switching processes of the washing machine and dryer, a temperature sensor and a switchable group of adjustable comparison variables to the inputs of one of the comparators assigned. In this way, the expenditure for the circuit arrangement according to the invention can be particularly high be small.

Another advantageous embodiment of the circuit arrangement according to the invention has another Comparator which, on the input side, senses the temperature of the drying room during drying Temperature sensor and with a fixed comparison element and on the output side with a cooling medium switch for connected to a condenser cooler. This additional comparator makes the one according to the invention suitable Circuit arrangement also to switch on the cooling medium flow only when after the Heating of the drying room the temperature of the laundry strong enough to give off moisture has increased

In addition, this further comparator is suitable as a replacement for a time-dependent controlled after-drying phase described above in that the further comparator is connected on the output side with the output of the comparator connected to the humidity sensor conjunctively / linked to a pulse control device for the drum drive motor. Then, for the duration of the drying phase ending the dripping program, which occurs after the dryer temperature has dropped to a certain lower temperature, e.g. B. 40 ⁰ C, has ended, the drum drive motor within short pulsed movement phases, z. B. for 5 seconds 'switched on' so that the cooling laundry does not get creases by maintaining a layer.

According to a development of the invention, the pulse control device is particularly expedient a clock. Such a clock generator is usually in terms of its pulse and pulse pause lengths adjustable.

When the pulse control means is further connected to an acoustic signal transmitter, the operator can be displayed is that the dry ■ program now completed.

On the basis of the exemplary embodiments shown in the drawing for a circuit arrangement in FIG. 1 and a modification of FIG. 2, the invention is explained below '·'.

The circuit arrangement in FIG. 1 contains four comparators 1 to 4. Electrical values to be compared are fed to each of their two inputs, eg electrical, resistance-dependent current or < ^{Λ voltage wave.} The comparators can be set up in such a way that, when the signals at their inputs match, they each emit an output signal.

But they can also be matched to specific differences between the input signals. The upper input of the comparator 1 is assigned to specific wash temperatures of the washing liquor. Resistance values are fed to the appropriate switch position of the switches 10-1 to 10-4. The lower input of the comparator 1 is connected to a voltage divider circuit 11 consisting of a fixed resistor 11-1 and a temperature-dependent resistor 11-2 connected as a temperature sensor.

The comparator 2 has its input side similarly connected as the comparator 1. its upper input, however, only two different resistance values can be fed, which in open switch 20-1, for example, the drying temperature is 60 ⁰ C but with a closed switch 20-1 a drying temperature of, for example, 100 ° C correspond. The lower input of the comparator 2 is also connected to a voltage divider circuit 21 composed of a fixed resistor 21-1 and a temperature-dependent one. Resistor 21-2 connected. So that the comparator 2 is switched ineffective during washing operation, a switch 21-3 of a program control device (not shown), which is closed during washing operation and which opens during drying operation and thereby effectively switches voltage control circuit 21, is parallel to resistor 21-1.

The comparator 3 is also connected to a switchable resistor combination at its upper input, which, when the contact 30-1 is open, supplies a resistance value corresponding to the drying result "iron dry", with closed switch 30-1 a resistance value corresponding to the drying result "cupboard dry". The lower input of the comparator 3 is connected to a converter 31 , the inputs of which are connected to two electrodes 31-1 and 31-2 which are arranged in the drying room and sense the laundry moisture on the basis of the conductance measurement. The converter 31 signals at its output increasing resistance values with decreasing residual moisture of the laundry to be dried.

A fixed value of the resistor 40 is entered into the upper input of the comparator 4, whereas its lower input is connected to its voltage divider circuit 21 in the same way as the comparator 2 4 a separate divider circuit can be dispensed with.

The output signals of the comparators 1 to 4 have jump characteristics at the moment of the occurrence of the input-side condition. The outputs of the comparators 1 to 3 are fed to a mixer 5, which is always then on the output side the relay 6 switches on if one the comparator 1 to 3 emits an output signal The output signal of the comparator 4 switches a relay 7 and is also fed to one input of a conjunction circuit 8, the other input of which is connected to the Output of the comparator 3 connected. The conjunction circuit 8 is followed by a clock 9, the when a voltage threshold is exceeded, the relay 12 activates in a pulse-like manner.

In washing mode, only the comparator 1 with its temperature sensor 11-2 is effective. The comparator 3 reports, via its electrodes 31-1 and 31-2, because of the high water level in the machine during washing, very damp laundry, that is to say a very low resistance value, and the comparator 2 is controlled by the control unit

switched ineffective by means of a switch 21-3. In addition, the switch 20-1 closed and the comparator programmed a temperature of 100 ° C. An output signal on Comparator 2 is therefore impossible.

Using a suitable combination of closed and open switches 10-1 to 10-4, the desired washing temperature is given to the comparator 1, which receives a corresponding resistance value at the lower input when this temperature is reached and sends an output signal to the relay 6 via the mixer S. This switches off the heating device 62 for the washing operation by means of its switch 6-1 via the contactor 61 and its switch 61-1. In addition, the program control device, not shown, performs a step via the normally open contact of the relay switch 6-1. Its coupling magnet 63 receives voltage via the switch of the water level sensor 64, the normally open contact of the relay switch 6-1 and its own switch 63-1. It leaves the so-called thermostop position, in which the control unit is known to stop until the desired washing water temperature is reached

During the subsequent program parts »Rinse« and »Spin«, all parts of the programmed in such a way that they cannot intervene in the program sequence.

In the program section "Drying", the control device activates comparator 2 via its program switch 21-3. By means of the selection switch 20-1, the comparator 2 is preprogrammed to a temperature adapted to the type of laundry to be dried (e.g. 60 ° C. or 100 ° C.). The comparator 1 is set to a temperature by means of the switch combination 10-1 to 10-4 which cannot be reached at the temperature sensor 11-2 during drying. This ensures that it does not emit an output signal at least during drying. Now only the outputs of the comparator 2 and the comparator 3 on the mixer 5 are effective, whereby the comparator 3 can be programmed to the desired final moisture level of the laundry using the selection switch 30-1. As long as neither the selected temperature nor the humidity is reached, the relay 6 remains in the illustrated, unexcited position. Its changeover switch working contact 6-2 carries the voltage R via the program switch 63-2, which is closed during drying, to the contactor 65. Its switch 65-1 is closed for so long and keeps the dryer heater 66 in operation. During the washing operation, the dryer heater is safely disconnected from the power supply by the open program switch 63-2 . The caustic heating device 62 remains switched off during drying because the water level sensor 64 cannot respond.

As soon as either the comparator 2 determines the temperature set on the switch 20-1 by means of its temperature beer 21-2 or as soon as the comparator 3 determines the desired degree of dryness via its electrodes 31-1 and 31-2 in accordance with the 4 position of the switch 30-1, one initiates the Ausgangssi- | but nak these two comparator the mixer 5, the energization of the relay 6, which via its switch 6-2 Trocknerheizvmg 66 turns off during the drying program, the desired drying temperature can be maintained with sufficient accuracy by a two-position control of the comparator 8, to The humidity sensor via its comparator 3 causes the heater 66 to be switched off for good.

The further comparator 4 switches when a predetermined temperature is reached at which there is already a significant amount of moisture in the dryer air and which can be, for example, 45 ° C via the relay 7 and its work switch 7-1 the magnet 71 in the water supply for a .) For example, a water-cooled condenser (not shown) lying solenoid valve 72. At the same time, the washing motor 13 can be put into operation via a further switch 7-2 of this relay, so that the laundry is frequently shifted and dried evenly. The comparator 4 has a relatively broad hysteresis, which is expressed in the fact that its output signal only decays when the temperature falls below a significantly lower temperature than must be present to switch on the output signal. This lower temperature can e.g. B. 40 ⁰ C or less. As a result, the comparator 4 switches back only after a longer cooling phase with the dryer heater 66 switched off, during which no further noteworthy drying effect occurs. Only then are the cooling medium for the condenser and the washing motor switched off.

During this longer cooling phase, an anti-crease program can be provided simultaneous presence of the output signals from the comparators 3 and 4 via the conjunction circuit 8 the operation of the clock 9 provides. Its cyclic output signals switch the relay 12 in rhythm of, for example, 5 seconds of operation and 20 seconds of pause. In this rhythm you can use his Switches 12-1 and 12-2 of the washing motor 13 - the program switch 63-3 is a matter of course when drying in the position not shown - and the signal generator 14 are switched on.

The modification shown in Figure 2 relates to the Circuit arrangement of the comparators 1, 2 and 4 in FIG. 1. This can namely through a common Comparators 124 are replaced for all temperatures to be recorded, the output of which with the mixer 5 The upper input of the comparator is connected via a suitably calculated comparison variable arrangement 240 of four resistors 240-1 to 2404, which are connected individually or in pairs through the Switches 240-5 and 240-6, which are a selector switch or can be assigned to a program control device, are effectively switchable, for one of eight desired Pre-programmable washing and drying temperatures.

The lower input is led to a fixed resistor 241-3 which, together with a temperature sensor 241-1 forms a voltage divider 241 which is ineffective when bridged by switch 241-2 is switchable

In addition to this one voltage divider 241, a second voltage divider of the same type can be used for a second temperature range can be provided, which in a manner not shown by a changeover switch alternatively to the first voltage divider can be effectively switched.

For this purpose 2 sheets of drawings

Claims (6)

Patent claims: 1. Circuit arrangement for the humidity and temperature-dependent control of a washing and drying machine equipped with electrical heating devices as a function of temperature and humidity sensors arranged in the washing and drying room and / or in the duct leading to the exhaust air of the drying device, characterized in that each sensor or each Group of sensors (11-2, 21-2, 31-1, 31-2) to which one input is assigned its own comparator (1 to 3) with step characteristics of the output signal, the other input of which with fixed or adjustable comparison variables (10 , 20, 30) can be acted upon, and that the outputs of the comparators (1 to 3) are connected via a mixer (5) to a switching device (6, 61, 65) for the heating devices (62, 66). 2. Circuit arrangement according to claim 1, characterized in that a temperature sensor (241-1) and a switchable group (240) of adjustable comparison variables (240-1 to 240-4) the inputs of one for all temperature-controlled switching operations of the washing and drying machine the comparator (124) are assigned. 3. Circuit arrangement according to claim 1 or 2, characterized in that a further comparator (4) is provided, the input side with a temperature sensor sensing the temperature of the drying room during drying (21-2) and with a fixed comparison element (40) and the output side with a cooling medium switch (7) for a condenser cooler is connected. 4. Circuit arrangement according to claim 3, characterized in that the further comparator (4) on the output side with the output of the comparator (3) connected to the humidity sensor (31-1, 31-2) conjunctively linked to a pulse control device (9) for the drum drive motor (13) is connected. 5. Circuit arrangement according to claim 4, characterized in that the pulse control device is a clock (9) 6. Circuit arrangement according to claim 4 or 5, characterized in that the pulse control device (9) is also connected to an acoustic signal generator (14).