DE1610314A1 - Method for operating a washing machine and device for carrying out the method - Google Patents

Description

File number: Z 11 581 VIIa / 8d 1)

The invention relates to a method for operating a washing machine for washing laundry with suds in a drum, whereby the Washing liquor is heated and to remove moisture from the washed laundry in the drum after spinning or instead of a spin cycle a heat source - preferably a microwave generator - is used, so that the * wash can be completely dried. This is done by a washing machine according to patent · ....... · (patent application Z 11 58I) assumed, the present invention is based essentially on the manner in which the trooken process was ended As is well known, the job of a laundry -

009885/0422

BATH ORIGINAL

trooken machine in it, the water content of the damp laundry up to to reduce a prescribed hatred «Here, various end states are aimed for, for example

iron dry "ie the laundry still has a low residual moisture content of about 15 to 10 fo or vo11trocken, that the residual moisture is zero, the loop has thus achieved its original dry weight again.

Because the performance of the dryer due to the constructive Established circumstances can in and of itself, proceeding from the state the wet wash, the required drying »is determined in advance will. For dryers with a timer to end the trekking process Due to the characteristics of the dryer, the housewife is able, depending on their skill, to determine the expected drying time to estimate or to calculate and set “Whether the desired dryness when switching off the dryer, however is achieved depends on many factors, their determination and Coordination is usually extremely difficult for a non-specialist is. The result is that the predetermination of the degree of dryness of the hash in trooken machines by means of timers is a very unsatisfactory and questionable matter is

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Various measuring methods are used to determine the moisture content of the material and measuring devices ". Most of the time, however, they are very expensive and much too cumbersome to use, so that they are out of the question for the household appliance industry in particular.

Control devices have already become known for trooken machines, which sense the electrical conductivity of the laundry by means of an electronic sensor and switch off the heating of the dryer when the desired dryness level is reached. There are also various deficiencies in these devices, so that their use on Trooken machines without separate equipment remained for a long time. In particular with dielectric drying by means of microwaves, such sensors cannot be used, since they would have to be arranged on the drum, whereby the measuring element would be negatively influenced by the effects of the microwaves.

In the German patent 1 080 801 is a device for Keefeen of the moisture of running Yarenbahnen described, whereby a temperature difference seaear is used, the temperature of which « sensors in the air flow gate and behind you Marenbahn are · Such a device is not suitable for vasohmaschimam referential trooken machines, where it is about »Wi Irrelohen a certain Re st damp to cancel the drying process because

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after reaching this residual moisture and continuing the drying process the temperature of the items to be washed rises so sharply within a short time that, if it is not switched off precisely, the correct one Time, washing damage due to overdrying and overheating of the Laundry can occur and, with drying using microwaves or microwaves and warm air (hybrid drying), even there is a risk of the laundry being burned.

In the German patent specification 1 153 472 an arrangement for J3in- and Aueschaltung a Koohplatte heater described, wherein a temperature-dependent resistance as temperature sensor and a second one temperature-dependent resistance as a second heat-sensitive organ in different branches of an electrical bridge circuit whose diagonal voltage enables the hotplate heating to be switched on and off causes · Apart from the fact that this known arrangement in connection with electrical heating devices, in particular Cooking appliances, the controls of these appliances operate on an intermittent basis, with their task is to determine the heating intensity or the Maintain temperature at a prescribed level. Also this well-known The arrangement is therefore not suitable for operating a washing machine or a drying machine.

BATH ORIGINAL 00988 5/04 22

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The invention is based on the object of a method for operation a washing machine and in particular a trooken machine create in which the dry air or the dry air causing microwaves is switched off at the end of the 'Pro okenvor ganges' will, or will, depending on a certain residual moisture of the laundry or the to trookendan. Good thing} the shutdown should essentially take place automatically, i.e. it should no longer be necessary, the necessary Drying time to achieve the desired dry state to be calculated and adjusted on the basis of several factors.

To solve this problem, a method for operating a washing machine is proposed, which is characterized in that the temperature difference Λ * v between supply air / ^ P £ and exhaust air ^ 4 is determined to switch off the energy generator when the preselected degree of dryness is reached during or near the end of the drying process and the temporal change in this tea temperature difference, ie its differential quotient (L Δ -ν / ¹ / at al * measured variable of the material humidity determining the time at which the heat generator is switched off) is used the amount of air required to cool the microwave generator as

BAD ORiGiNAL

009885 / 0A22

Eätzliehe heat source introduced into the washing drum, with addition of the technical function an improvement of the troublesome degree is achieved through the hybrid drying «

The invention is thus essentially based on the fact that the material humidity is determined indirectly from the characteristic course of the inlet and outlet air temperature during the drying process. Since the supply air temperature remains practically constant, apart from the heating-up time, and the exhaust air temperature rises rapidly in the end phase of the drying process, i.e. from a certain residual moisture r * , the temperature difference Δ rJ> of the two temperatures is a means of determining the Degree of dryness of the laundry. The temperature difference Δ rfh, however, does not yet allow a definitive statement about the dry state of the laundry, since on the one hand disturbance variables influence the characteristic curve and on the other hand the

The size of the temperature difference 4 <^! H due to the characteristic

Course of the troubling speed j '/'. , _ \ ^ to the beat ι o / Ty)

The mood of the trooken grade cannot be used directly. Therefore, the temperature difference Δ a / * is not used to determine the degree of dryness, but the change in this temperature difference over time, i.e. its differential quotient dArJ * / di ale Hessian variable, where constant values are known to be zero and thus eliminated, as well as the increase and decrease of a phyaika -

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Thanks to its mathematical sign, n hawaii to get into let the positive and negative parts separate.

These properties are an essential part of the device according to the invention for carrying out the method. It is characterized by a in the output circle on a change in the Temperature difference appealing bridge with its primary coil lying transformer, which the the temporal temperature change in the primary circuit occurring proportional current decrease di / dt is transformed into its secondary circuit, in which a holding relay that influences the power supply of the microwave generator lies. The transformer has two functions, namely

a) To galvanically separate the primary circuit (sea organ) and secondary circuit (actuator), and

b) convert the change in temperature over time into a proportional change in current.

Although it has been assumed so far from a troubling by means of microwaves it is to be understood that the invention is also preferred Use with one · dry or Maechtrockenautoaaten in which any other heat source is used.

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The invention is explained in the following with the aid of the accompanying drawings Figure 1 - Figure 7 described in more detail. It rise:

Fig. 1 in principle the electrical circuit arrangement to carry out the procedure,

Fig. 2-7 Curve diagram of the individual variables determining or reflecting the drying process.

The microwaves used for drying are generated by the microwave generator or magnetron 113. In the control line 112 of the magnet station 113 there is a contact switch 111 actuated via a relay 110. Ue the magnetron 113 or other heat sources 113a at the correct point in time by opening the contact switch 111 (position 111a) switch off, the relay 110 duroh the The circuit arrangement making up the invention is operated, which, based on its mode of action, is referred to as a "differentiating element" can be·

The differentiating element consists of a bridge circuit 114, the τοπ a direct current source 126 is fed. In both of them ever a feed point 114 ^ or 114 "of the bridge circuit 114 at the base of the bridge arm 114a and 114b, which each lead to the

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Both starting points 114g ^{un (} i 114 £ lead, a temperature sensor (hot conductor in the form of non-linear resistors) 115 or 116 is switched on. The temperature sensor 115 measures, for example, the drying air rs / Έ to the laundry. The air heated by the magnetron is used for this 116 measures the Trooken exhaust air coming from the Fäsohe / * A. Supply air and exhaust air are shown by the double arrows S and A.

The current flowing in the direction of the arrow 124 in the output circuit of the bridge arrangement 114 is fed via an amplifier 119 (which in principle is not required) to the input circuit 117 cLes the differential element forming the core element 130 from the differentiating element, which is shown in the basic circuit diagram as a transformer 118 with the primary side 118a is shown, but can also consist of an RC combination 127. Between the output circuit 121 of the secondary site 118b of the transformer 118 and the circuit 121a of the relay 110, an amplifier 126 is interposed. The desired degree of dryness of the laundry is set at the amplifier 126 with the potentiometer 120, although the potentiometer is in principle arranged directly in the line 121 and 121a if the amplifier 126 is omitted. The blocking rectifier 122 (diode) connected to circuit 121 only allows current to flow in one direction as indicated by arrow 123, so that the undesired portion of the differential quotient is suppressed »

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The operation is as follows, the supply air temperature door λ # ε "is the by the sensor 115 (Figl 1) is measured, has, starting from room temperature, a relatively eteieln initial slope of the curve nash 14O (Fig. 2) following a substantially constant Grosse ( JcLJt. - 1), the absolute value of which depends on the configuration and the intensity of the heat source. The exhaust air temperature * v * A , which is measured by the sensor 116 (FIG. 1), after a significantly less steep rise see curve 141 (FIG. 2), also based on room temperature, has an initially practically constant temperature of about ^ i / Av ** «0.45 Towards the end of the dry

/ τ I

time, ie when the laundry is iron dry with about 15 ^ reed moisture see curve 142 (Fig. 4), there is initially a further small increase see curve 143 (Fig. 2) of the exhaust air temperature to about «χΛ ^ / α / λλα / »0.5 * From this point the temperature rise in the laundry increases considerably and, if drying is not interrupted at time tr / Tr - 1 (Fig. 2), the laundry temperature would after a short time reach the supply air temperature ^ g / vViftx rise η ^ as from the course of the exhaust air temperature Λ ^ ι. A ^ ma * in the region of tr / Tr (Fig. 2) can be seen ü. This could lead to damage to the laundry, especially in the case of hybrid drying with microwaves, with excessive drying being quickly withdrawn from the tissue, so that local overheating due to uneven field distribution of the microwave energy could cause the laundry to ignite itself .

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In order to be able to interrupt the drying process in the final phase with certainty, the prescribed differentiating element is used. As already mentioned, the material moisture Ύ or the dryness degree (Ϋο-y ) is determined indirectly from the characteristic course of the inlet and outlet air temperature during the drying process. The connection of the Teoperaturdifferenz mer 'two temperatures bit of the humidity or the dryness of the Wipe 4 * Aue show in normalized representation of Fig. 2 and Fig. The course of the Jiäsohefeuohte tiΎ · _t aiehe curve 144 (Fig. 4) results in duroh difference formation of ( > _e - »/ Yo the time-dependence of Liehe Trockengradββ _£ see curve 145 ^(FIG x 4) · the differential

quotient is the drying speed, shown d (trI Tr)

through the curve 146 (Fig. 4), which, according to the laws of thermodynamics, is a bit of the temperature difference in a causal relationship, see curve 147 (Fig. 2) a <J * Ut *. \ * and thus resemble their characteristics . The tea temperature dilution of the two temperatures is a means for the indirect determination of the degree of dryness of the temperature. Among other things, as already mentioned, to switch off the variables influencing the measurement accuracy in a negative sense and to be able to carry out a separation of positive and negative components 148, 149 (FIG , but those

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Temporal change in this temperature difference according to FIG. 3j, i.e. the differential quotient d. OrJ ⁷ JcIi used as a measured variable. The circuit arrangement according to FIG. 1 is used for this. The temperature difference δ λ? is formed in a known manner in the bridge arrangement (Pig. 1), consisting of the four resistors 115, 116, II5 ¹ and 116 ', as an equivalent current 124, the course of which shows, for example, FIG. 5 i ^Q standardized representation. D _g r from the amplifier 119 (Fig. 1) flowing analog current 117 (Fig. 1) is the actual. Union core 13§> (Fig. 1) -dee differentiating element supplied) where a current change di / dt proportional to the temperature change over time, as shown in FIG. 6, is either transformed into the secondary circuit of transformer 118 (FIG. 1), or as an equivalent Voltage change du / dt at output EC combination 127 (FIG. 1), consisting of capacitor 128 and resistor 129, appears for purposes of reporting a current outflow in the opposite direction of current 123 according to arrow 125 in secondary circuit 121 (FIG. 1) When drying begins due to the significantly steeper rise in temperature of the supply air I40 (Fig. 2) than the exhaust air 141 (Fig. 2), the blocking rectifier is used, i.e. the diode 122 (Fig. 1) »3s win * while the positive component 148 (Fig. 2) is used . 3) or I50 (Fig. 6} of the differential quotient is suppressed, so that only the one used to determine the degree of dryness -

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"for example" iron dry "142 (FIG. 4)" or 152 (Fig. 7) - decisive negative portion 149 (Fig. 3) or 151 (Fig. 6) is used as the measured variable. The diode 122 (Fig. 1) can be omitted, if the amplifier 126 (Fig. 1) only works in one direction, i.e. only allows the current in the secondary circuit 121 (Fig. 1) to flow in the direction of the arrow 123 (Fig. 1). So an exact shutdown the heat sources 113 or 113a (Fig. 1) when reached the desired degree of dryness of the laundry takes place, an unspecified tilting stage is provided in the amplifier 126 (FIG. 1), which is only set when the value set on potentiometer 120 (Fig. ^ I) is equal Setpoint with the actual value 121 (Fig. 1) the circuit 121a (Fig. 1) switches on and the relay 110 (Fig. I) to respond brings, whereby the contact 111 arrives in Sohaltstellung 111a (Fig. 1) and circuit 112 (FIG. 1) opens.

BATH ORIGINAL 009885/0422

Claims (8)

Claims 1. A method of operating a washing machine for washing laundry using detergent solution in a drum, the Washing liquor is heated and a heat source - preferably a heat source - to remove moisture from the washed laundry in the drum Microwave generator - is used, characterized in that to switch off the energy generator when the preselected degree of dryness is reached during or at the end of the During the drying process, the temperature difference between supply air and exhaust air is measured and the change in this over time Temperature difference, that is, its differential quotient d λ if * / <H bXb Measured variable of the material moisture determining the time at which the heating device is switched off is used. 2. Device for performing the method according to claim 1, characterized in that a differentiating element (130) is used to form the differential quotient άΔιΡ / οίί, which converts the change in temperature Δ λ / * measured in a bridge circuit (114) into a proportional one Change in current di / dt or change in voltage du / dt converted 00 9885/0422 ^BAD original -JiT- delt, and the power supply of the Heat sources (113 or 113a) influencing relay (110) is supplied. 3. Eii.richtung according to claim 2, characterized in that · that the differentiating ßlied (130) contains either a transformer (118) or an RG combination (127) whose output signal as the actual value of the laundry dryness level in an amplifier (126) for the target - actual - Ve: equals » 4. Device according to claim 2 ~ 3 _f, characterized in that the temperature! Ifferenz 4 /, which is formed in the bridge circuit (114) by the temperature-dependent resistors for supply air (115) and exhaust air (116) arranged as a temperature sensor s in dei * 3 back diagonal (114g - 114 |) has a proportional current sur sequence, the respective amount of which has no direct influence on the switching relay (110), but which, when the temperature difference changes as a result of the increase in the exhaust air temperature in the final phase of the drying process, as a change in strosi di / dt is fed to the amplifier (126), whereby a current in the output circuit (121a) causes the switching relay (110) to respond when the target value is reached. BATH 009885/0422 J * 5. Device according to one of claims 2-4, characterized gekennzeichenet that between the circuits (124 - 117) and (121 - 121). A respective \ ^r erstärker is connected, the amplifier (119) for amplifying the current bridge (124 ) and simultaneous relief of the bridge diagonal (itAp-H ^ y) , on the other hand, the amplifier (126) works as a switching amplifier with a built-in multivibrator, which is triggered on the basis of the target-actual comparison in the amplifier, for which the target is set by means of a potentiometer (120) Value is set. 6. Device according to one or more of claims 2-5, characterized in that optionally in the circuit (121) a blocking rectifier (122) is located, 7. Device according to one or more of claims 2-6, characterized in that for detecting the supply air temperature « For drying with microwaves, the amount of air required to cool the microwave generator as additional BAD 009885/0422 Heat source is introduced into the washing drum and next to the measuring technical function brings an improvement of the drying efficiency through the hybrid drying. For the applicant: ,:, .. ■■ <*} · vr, ι ,: Γι ^ ι η Bremen d. June 8, 1967 Applicant: Hermann Zanker
Maschinen- und Metallwarenfabrik limited partnership. 74 ΐ ti am ^; go ''^; Addition to patent ........ (patent application file number: Z 11 581 VIIa / 8d 1) 0098 85/0422. _B AD