EP0679754A2 - Method and device for treating textile products during drying - Google Patents

Abstract

The chemical dry cleaning assembly, for clothing has a throttle (9) in the air recirculation system between the fan (7) and the cooling register (11). A gas measurement and control system (23) is connected to the temp. monitor (25) in the air flow (5) at the outlet side (3) of the drum (1), and to a pressure monitor (27), also with a link to the heating register (13). The heating register (13) is switched on and off according to the air flow (5) temp. and the throttle (9) is activated. A monitor (41) in the drum (1) gives a non-contact measurement of the temp. of the material being processed and is connected to the gas measurement and control (23) system. A controlled water contact unit (31) delivers water (45) to the drum (1) through a drying control (17) between the drum (1) and it. Also claimed is a control operation where the air flow vol. is constantly varied according to the concn. of solvent vapour in the air flow, taken at least from the temp. and pressure of the air flow at the outlet side of the drum. The temp. at the inlet side of the drum is lowered if the outlet temp. is higher than a set value. The temp. of the material being processed is measured without contact. When the material temp. rises, the heating register is disconnected and the cleaning process is stopped when the gas concn. in the air flow drops by more than a given value. Water pptd. from the air flow is caught before the cooling register, and returned to the processed material as a vapour in the drum when the air moisture content of the material drops below a certain value. The air moisture content is measured as well as the temp. and pressure. <IMAGE>

Description

The present invention relates to a method and a device for the treatment of textile goods during the drying process in dry-cleaning machines, washing machines, tumble dryers and the like, as well as special devices for chemical surface treatment of textiles that use a circulating air stream and a solvent, or devices that only remove water and therefore no solvent and in which the air flow is circulated or open and those that have a heating register.

In chemical cleaning machines, the work sequence generally consists of the steps of cleaning, spinning and drying textile goods, only the drying process being important for the present invention. For washing machines that provide drying, only the drying process is also of interest.

The invention relates to the current state of the art of machines with open operation or closed circuit based on the course of the air flow required for drying. Open operation is to be understood when the air is sucked in from the surroundings and blown back into the surroundings, whereby indoor air or outside air can be used. The closed circuit has a closed circulating air flow on which a condensation phase with a subsequent so-called reduction phase is subjected in an associated activated carbon system, in which the solvent content of the air flow is reduced. To understand the invention, the devices mentioned at the outset are also referred to as machines which include the drying process.

After the centrifuging process of the goods (textiles) has ended, moisture is disposed of in machines that include a drying process using the drying process, in that air with an inlet temperature of approximately 90 ° C. is passed into the drum of the machine over the textiles to be treated and thereby the solvent, such as PER, is implemented in gas form. The air flow temperature drops to about 20 to 25 ° C at the drum outlet, for example by directing the air flow through a cold register, for example by means of a blower, where the gas condenses from the air flow. Up to now, inlet temperatures higher than 90-95 ° C have been considered harmful to textiles. It was assumed that this is the highest temperature limit to which the textile goods can be exposed without being damaged. In addition, it is generally required that the temperature of the goods must not fall below 35 ° C to prevent recondensation. If the temperature of the goods were below 35 ° C, the textile goods would absorb the solvent from the air and store it, thus achieving a filtering effect that is undesirable.

The temperature of the air in the drum is recorded in modern machines including a drying process with metal sensors (e.g. PT100; thermocouples) that are located within the device system and fed to the control electronics, whereby the temperature of the air flow is not measured, but the temperature of the goods . The temperature of the goods as such has not yet been checked. Since at the start of drying more than 20,000 ppm (particles per million) solvent concentrations are reached in the drum area, which drop to a fraction of them at the end of drying, these temperature sensors are subject to heat removal, which inevitably leads to measurement errors. This is attempted to compensate by setting the inlet and outlet temperatures accordingly low. The actual temperature of the goods is therefore not recorded. It was assumed that the air temperature corresponds to the temperature of the goods.

The condensed solvent, in particular in the case of dry cleaning machines, is drained off and collected via the cold register and fed to a so-called contact water device via an associated dry control device. In the contact water device, the solvent from the distillator is mixed with the solvent from the cold register from the drying process in order to obtain a rough pre-separation of the dissolved water. This so-called contact water is later disposed of via a contact water system. It is not possible to return the water extracted from the goods to the drying process, since the water from the distillator is obtained as an azeotropic mixture and is usually only changed very rarely and therefore experience has shown that it smells unpleasantly strong.

When the drying process has progressed to such an extent that only very small amounts of solvent are obtained in liquid form, the drying process is ended via the drying control device and the so-called reduction phase is initiated. Such a process is known in a chemical cleaning machine from DE-AS-22 36 683. This means that the heating register on the dry cleaning machine is switched off. At this point there are still solvent gas concentrations of 1200 to 3000 ppm in the drum space and up to 8% solvent in the goods. During the reduction phase, the drum is therefore no longer supplied with heat in order to only reduce the solvent content in the air flow.

In order to achieve the lowest possible temperature in the cold register so that the solvent in the cold register is condensed as completely as possible, the speed of the blower is additionally reduced in some dry-cleaning machines, which is difficult to solve in terms of control technology, since suitable precise parameters for this are missing. In order to come as close as possible to an environmentally friendly desired or required value of less than 280 ppm, the air flow, as is known from DE-AS-22 36 683, is passed through an activated carbon plant and reduced there to the specified value.

The parameters that influence drying are: air flow, gas concentration, temperature-gas measurement at the drum outlet or inlet, temperature before or after the condenser, moisture content of the air, gas pressure, temperature of the goods, additional heating, drying time, reduction time, loading weight of the Drum, type of goods (diffusion behavior), fluff catcher load, spin cycle, cold register (condensation capacity), activated carbon filter, air humidity.

This shows the difficulties involved in finding suitable parameters for regulating the air flow in the dry phase of the goods, which are reliable enough to carry out the drying of textile goods under economic conditions. For example, in the known dry cleaning machines, the dry control device only detects the already condensed solvent behind the cold register and does not take into account which textile quantities or textile types are dried, nor the actual residual solvent content in the air flow and in the goods. Therefore, undesired different degrees of drying are also achieved.

In particular, the dry control or regulating device does not recognize any temperature fluctuations in the air flow in the drum area, which inevitably occur during the drying process, nor does it recognize the influences of the temperatures outside the dry cleaning machine, which, depending on the season and location, influence the drying time factor during gas phase formation up to 30% . In addition, it does not control the air humidity based on the water content of the air flow, which is of particular importance. Of course, this also applies analogously to other machines that include a drying process. The demands of the clothing industry, which do not allow dimensional changes of the textiles, cannot be satisfied by such measuring methods. If the goods are over-dried due to excessive temperatures, irreversible damage will result from water being removed from the fiber, which is particularly the case with sensitive textiles such as mohair and pure wool.

From DE-A1-32 34 105 a chemical cleaning machine with a circulating, closed air flow is also known, in which the solvent concentration in the washing drum housing is reduced after the washing process has ended and before the unloading door is opened by drying air through the goods and cleaning or recovery devices are circulated until a solvent vapor concentration is reached which allows the unloading door to be opened without exposing the surroundings to an excessive solvent vapor concentration. The cleaning device can consist of an activated carbon filter, while the recovery can be carried out by freezing. Flaps for controlling the air flow are also described, which are provided for reversing gas flows when the operating states change from closed to open unloading door.

Due to the decrease in the amount of solvent in the goods during their drying, the drum outlet temperature gradually increases, and with it the temperature of the goods, while the evaporative cooling capacity in the drum on the textile fibers decreases at the same time. This in turn means a higher energy input to the cold register in dry cleaning machines and automatically leads to the temperature on the outlet side of the cold register rising, which means a higher solvent concentration in the air stream and is not desired. Measurements have shown that up to 8 minutes of drying time are wasted because during this phase the gas concentration at the cold register inlet shows almost no gradient compared to the cold register outlet.

This drying process control has so far not been able to influence the gas-forming condensation processes in the air flow, since this control only detects the already liquid-condensed solvent which emerges from the cold register of the dry cleaning machine.

In previously known drying control methods, a gas measuring device is usually attached to the drum outlet. This is required in order to prevent the loading door from being opened while there is still more than 280 ppm solvent gas concentration in the drum space.

The residual solvent content in the textiles is not recorded here. Furthermore, these devices are technically designed so that they can measure either in the range of 0 - 800 ppm, or in the range of 800 - 20,000 ppm. Such devices can therefore not measure the entire drying process and control it optimally. In practice, these devices are also not used for regulation. A gas measuring device with a more precise measuring range of 0 to 800 ppm is preferred. An optimal measurement of the drying process by these devices at a gas concentration above 800 ppm is not possible. Thus, the entire measurable gas concentration range within the drying process is not covered by a single gas measuring device.

For dryers that remove water from textiles, the drying process is carried out in the simplest form by a purely time control. The heating power for heating the air is set to a fixed value and the goods are treated for a fixed period of time. Since the type and moisture content of the goods are often subject to fluctuations, an energy-optimized and laundry-friendly use of this type of control requires a great deal of experience and care from the operating personnel. Therefore, a control is often used in which the air humidity is measured at the drum outlet. If this falls below a certain value, drying is complete. This takes into account different air humidity levels, but not directly the residual moisture in the textile fiber.

Air temperature control also takes place. Depending on the sensitivity of the laundry, a corresponding target temperature for the air in the drying drum is set. This temperature is measured at the drum inlet or outlet or both using conventional temperature measurements (PT100, thermocouples) and set using a heating register.

The problem with the regulation is that drying is generally carried out less than optimally. Basically, the drying performance is best when the air temperature is as high as possible. However, as mentioned, the temperature of the goods must not exceed a maximum value, otherwise excessive wear and damage to the textiles will occur.

In the previous control and regulation methods of the dry cleaning machine or machines including a drying process, the temperature at the drum outlet is taken into account, which increases with the decrease in the amount of solvent and can cause the goods to overheat, but the actual temperature is not, as mentioned, of the goods measured.

It is therefore an object of the present invention to provide a method and an apparatus for treating textile goods during the drying process in dry-cleaning machines, washing machines, tumble dryers and the like, which optimize the drying process over the entire duration of the drying process by a sufficiently small amount To achieve water content or to achieve a low solvent concentration of less than 280 ppm on the outlet side of the drum, which considerably shortens the drying time and saves energy.

According to the invention, the object is achieved by a method which is characterized in that the temperature or the humidity of the surface of the textile goods is measured without contact and, depending on the measured values, the air flow, the air temperature or the humidity is influenced during the course of drying.

Furthermore, the air volume flow and / or the air temperature is continuously changed as a function of the contactlessly measured temperature or moisture on the surface of the goods and as a function of the gas concentration of the solvent in the air flow, the gas concentration of the solvent being at least based on the temperature and pressure of the Air flow is determined on the outlet side of the drum and the temperature on the inlet side of the drum is lowered if the temperature on the outlet side of the drum or on the surface of the goods exceeds a predetermined value.

In addition to the temperature and pressure, the humidity content of the air flow can be measured on the outlet side of the drum.

Furthermore, the heating register is regulated and switched off as a function of the temperature or humidity of the surface of the goods by means of a control device, when the gas concentration of the air flow drops below a predetermined value to end the drying process.

In a further embodiment of the method according to the invention, the amount of water occurring in the air flow during the drying process in addition to solvent is collected from the goods and returned to the goods in gaseous form when the moisture content of the goods drops below a predetermined value.

Furthermore, the object is achieved according to the invention by a device, in particular a chemical cleaning machine, washing machine, tumble dryer or similar device for carrying out the method according to the invention, which uses a circulating air stream and an organic solvent or water, or only a circulating or an open air stream, and one Has drum for receiving the goods, a heating register, a control device and optionally a blower and a cold register, in that in the area of the drum a measuring device for non-contact measurement of the surface temperature or the moisture of the goods is arranged, which is in operative connection with the control device stands, which, depending on the measured values, regulates the air volume flow, the air temperature or the humidity continuously during the drying process by means of a throttle device located in the air conveying path The fan provided on the output side of the drum and on the input side of the cold register is arranged. Furthermore, the task for devices that are not equipped with a movable drum, such as Tunnel finishers and baking ovens, solved by a measuring device installed on the wall of the room, for example, which enables a control of the air volume flow in the manner described above by contactless measurement.

In a preferred embodiment of the invention, the measuring device is attached to the loading and unloading door of the drum. The measuring device is expediently located essentially in the plane of the axis of rotation of the drum. In systems without a drum, the measuring device is generally installed at the level of the hanging or lying textiles.

Furthermore, the throttle device is arranged in the air conveying path. The throttle device can be, for example, a throttle valve or a throttle valve.

Finally, a temperature sensor, a pressure sensor and / or a humidity sensor are arranged on the output side of the drum and are connected to the control device.

The invention first provides a measuring method for the contactless measurement of the temperature of the goods. It is a measuring device based on the principle of the optical radiation pyrometer, for example an infrared or other radiation measuring device. The radiation emission of the textiles is recorded in the infrared range. The air or the air-water mixture between the goods and the measuring device has an absorption factor of α = 0. This means that there is no heat radiation from the air and only the actual surface temperature of the goods is measured.

The surface temperature can differ from the temperature inside the goods, but this is of no importance, because due to the physical process of drying with a corresponding need for heat of vaporization and due to the convective supply of this heat from the outside via the heated air flow Goods will always set a temperature below the surface temperature. Possible damage to textiles due to excess temperature can therefore only occur on the surface, and it is precisely there that the temperature is detected according to the invention.

Due to the evaporation or drying process, complex heat and mass transfer processes take place at the interface between goods and air. For this reason, the temperature of the goods is generally not identical to the temperature of the surrounding drying air. In general, it can be assumed that the temperature of the goods at the start of the drying process is considerably lower than the air temperature. According to the invention, however, it is possible to work at high temperatures, especially at the start of drying. This high temperature is then adjusted using a suitable control system with the surface temperature of the goods as the control variable and the output of the heating register for the drying air as the control variable. Due to the complex conditions on the surface of the goods, non-linear controllers, for example based on fuzzy logic, are usually required for this application. The non-contact temperature and moisture measurement of the surface of the textile goods in the drum in connection with the fuzzy logic allows the different sensitivities of the textile goods to be differentiated and thus to adapt the drying process to the type and sensitivity of the textile.

Depending on the system conditions, a mere regulation of the heating register is not sufficient to achieve the desired product temperature, so that additional adjustments in the form of a throttle valve in the air conveying path are additionally required. Their control is also carried out automatically by the control device.

The tests have shown that the desired low solvent concentrations of less than 280 ppm, particularly in a dry cleaning machine, can now be achieved even without an activated carbon plant, so that a technically and cost-intensive part of the machine is eliminated. For economic reasons, an activated carbon filter can still be provided to further reduce the solvent content in the air flow. In particular, however, the new process ensures that the residual solvent concentration in the textiles is reduced again from approximately 1% of the goods weight to less than 0.4% of the goods weight.

To achieve this goal and to achieve the object of the present invention, the control device, which forms the central control device of the dry cleaning machine or a machine that includes a drying process, requires the information about the gas pressure, the gas temperature, the gas volume flow and, if appropriate, the air humidity the exit side of the drum. These data are recorded by the corresponding measuring devices, namely temperature, pressure and humidity sensors, at the drum outlet and passed on to the control device.

The control device exerts an influence on the temperature and the air pressure in the drum by reducing or increasing the air volume flow between the drum outlet and the cold register inlet via the throttle device, which is preferably a throttle valve.

Furthermore, the control device is connected to the measuring device installed on the window of the drum, which measures the actual temperature of the goods without contact. The non-contact measurement of the temperature of the goods has the particularly great advantage that the actual temperature and moisture content of the goods are recorded immediately, so that a really realistic value is obtained. The control device monitors whether the temperature of the goods exceeds a set or predetermined limit value. It switches off the heat supply in the heating register when the limit value is exceeded and controls the throttle device in parallel and thus immediately the temperature and the volume of the air flow. It is also possible that the non-contact measuring device alone takes over the operations of the regulating device, ie that the entire control and regulating electronics are accommodated in the measuring device.

In order to get an optimal drying time, a high gas concentration should be aimed for at the beginning of the drying process. This can only be achieved at very high temperatures. At about 25 ° C outlet temperature of the air flow at the outlet of the drum there are about 280 grams of solvent in the air flow per cubic meter. At 60 ° C, this is already 800 grams, more than double. It often takes 4-5 minutes to reach the optimum inlet temperature on the drum, since the self-losses of the heating register and the drum walls consume a lot of energy. A fixed temperature value of, for example, 90 ° C would mean considerably more drying time than a regulated value of 120 ° C. At the same time, however, a surface temperature of 120 ° C would damage the goods, namely the textiles.

A regulation of the surface temperature according to the invention prevents this damage, since it rules out any possibility of the goods overheating. This makes it possible to expose the goods to air temperatures above 95 ° C.

The method according to the invention simultaneously measures the airflow temperature on the outlet side of the drum, the gas pressure of the airflow and, if appropriate, the air moisture content in order to regulate the temperature on the inlet side of the drum when the cooling register is switched on by actuating the throttle device or switching the heating register on and off. Therefore, if the temperature on the output side of the drum rises above a predetermined value, the temperature on the input side of the drum is automatically reduced by the control device because the throttle device reduces the air flow and the heating register is switched off. On the other hand, if the temperature on the output side of the drum drops to a predetermined value, the control device increases the cross section of the air flow with the aid of the throttle device and switches on the heating register, so that the temperature on the input side of the drum rises.

The moisture content of the air flow also plays an important role in the drying process. Due to the particularly high requirements placed on emission reduction, the current state of the art brings about a disadvantageous reduction in the natural residual moisture content of the goods to be dried.

The intended humidity sensor can also be used to return water to the goods in the drum. If the amount of humidity drops below a specified value, the amount of water in gaseous form is automatically returned to the goods, thereby preventing it from over-drying. If the gas concentration drops to the specified value, the drying process is automatically ended. As mentioned, the drying process is optimized by the automatic control of the temperature on the inlet and outlet side of the drum. By early detection of low gas concentrations, the temperature on the inlet side of the drum and the speed of the solvent-air mixture are then automatically reduced, so that a reduction in the gas concentration of the solvent to below 280 ppm is achieved without an activated carbon system

The relationship between air flow, air pressure, drum inlet and drum outlet temperature and, if applicable, the air humidity is of the utmost importance with regard to the cold register inlet and outlet for dry cleaning machines. If the air flow and therefore the energy input upstream of the cold register input is too strong, the condensation capacity is reduced because the interface temperature of the cold register increases. This is the reason for a reduction in condensation. In order to optimize the drying performance, higher temperatures are required in the drum area at the same time, because an air flow with a low temperature means low condensation on the cold register. This results in the necessary regulation of the ideal conditions for optimal control of the drying process.

Drying is accelerated by the fact that a negative pressure is created in the drum in relation to the external pressure. In connection with an improved condensation of the solvent-saturated air flow at the cold register, an air flow is generated which, due to the negative pressure, is able to transport a higher proportion of solvent air to the cold register than usual. In particular, a necessary ratio of the diffusion rate within the voluminous textiles (winter goods) is created at the end of drying; in summer, light textiles are also taken into account automatically.

This process step is based on the following control process. Since it is an airtight system in the machine that includes a drying process, the mass of air is constant during the drying process. At the end of drying, the control device can be operated via the throttle valve reduce the passage of air in the air path. This creates an increased pressure between the blower and the throttle valve. Since the mass of air in the circuit remains constant, the air volume and thus the air pressure on the rest of the system, especially in the drum, decrease. Depending on the type of textiles, the throttle valve is more or less closed. Accordingly, a different pressure drop and thus a more or less large negative pressure builds up in the drum

Contrary to expectations, it has been shown that despite the high temperatures of, for example, 120 ° C. at the entrance to the drum, there is no damage to the goods, since high evaporative cooling is generated in the corresponding time range. This can also significantly reduce the total drying time if the temperature control is already carried out in an optimal manner at the beginning of the drying process, with a high air flow being required at the beginning of the drying process in order to achieve sufficient ventilation and heating of the goods for gas phase formation in a short time .

In principle, high temperatures of up to 150 ° C on the inlet side of the drum can be used at the beginning of the drying process. Such high inlet temperatures have hitherto been considered impossible to achieve, but are made possible by the present invention.

The natural fibers, such as cotton, contain up to 35% and more natural water, depending on the moisture content in the air. If this water is removed from the fibers, there is a shrinkage in the textile fabric, which is not desirable. However, this contradicts the attempt to achieve the lowest possible solvent concentration in the air flow. Therefore, as mentioned above, the water is returned at this drying time.

In addition, it should be emphasized that the above-mentioned parameters, namely inlet / outlet temperature on the drum, pressure and humidity of the air flow, temperature before and after the cold register and solvent concentration in close relation to the drying time, the reduction time, the loading weight of the drum, the type of goods , the lint trap load and the spin time before the drying process.

The non-contact measurement of the surface of the goods can in principle also be used for laundry shortages in order to regulate the drying air volume. Even with so-called The non-contact temperature measurement according to the present invention can be used in ovens in which the surface of the textiles or the textile material is finished.

Fig. 1:

eine allgemeine schematischer Darstellung des Grundprinzips einer einen Trocknungsprozeß einschließenden Maschine mit geschlossenen Luftkreislauf und

Fig. 2:

ein Ausführungsbeispiel einer Chemisch-Reinigungsmaschine mit geschlossenen Luftkreislauf.

The invention is described in exemplary embodiments with reference to the accompanying drawings. The drawings show in

Fig. 1:

a general schematic representation of the basic principle of a machine including a drying process with a closed air circuit and

Fig. 2:

an embodiment of a dry cleaning machine with a closed air circuit.

The schematic representation in Fig. 1 shows the general design of a drying system in which the air is circulated. In open operation, however, the cold register, shown by the dash-dot-dash line, through which the exhaust air is conducted, is not required and the air is not circulated. However, this is not important for the present invention.

The air in the air conveying path 5 is sucked in by the blower 7 and transported with it into the heating register 13 and optionally via the cold register 11 to the drum 1. The goods are dried in drum 1. The air enriched with water vapor or solvent leaves the drum 1 and returns to the air conveying path 5.

The drying is controlled by a control device 23. The surface temperature of the goods to be dried is recorded with the non-contact measuring device 41. In the control device 23, it is compared with a target value and the heating register 13 is set accordingly. Furthermore, the blower 7 is also set in order to achieve the desired surface temperature of the goods.

When the temperature is measured by the temperature sensor 25, limit value monitoring is carried out in order to avoid overheating of the goods in the drum 1.

The non-contact temperature measuring device 41 serves as well as the temperature measurement by the temperature sensor 25 and the air humidity measurement by the Humidity sensor 29 for recognizing the end of the drying process. The drying process is ended when the corresponding temperature or air humidity is measured at the temperature measuring points, namely the non-contact temperature measuring device 41 and the temperature sensor 25, or at the measuring points, namely the air humidity sensor 29 and the non-contact temperature measuring device 41.

Fig. 2 shows a dry cleaning machine with a closed air circuit which is explained in more detail below. The central part of the chemical cleaning machine is the drum 1, which on the output side 3 merges into an air conveying path 5 which, as can be easily seen from the drawing, forms a closed circuit. The direction of circulation of the air flow is indicated by the corresponding arrows in the air conveying path 5.

A fan 7 is arranged in the air conveying path 5, which sucks the air flow containing the organic solvent out of the drum 1, so that a negative pressure is created in the air conveying path 5 in front of the fan 7. The blower 7 conveys the solvent-air mixture in the air delivery path to a throttle valve 9, an overpressure area being created between the blower 7 and the throttle valve 9. Downstream of the throttle valve 9 is a cold register 11, which is followed by a heating register 13.

The air conveying path 5 continues from the heating register 13 to the inlet side 15 of the drum 1. A drying control device 17 is arranged on the inlet side of the cold register 11, into which condensed solvent and water run off and which is supplied to the contact water device 31 in a conventional manner (not shown). The dry control device 17 contains a conventional known level control, not defined in more detail and not part of the subject matter of the invention, which operates via a corresponding float 19.

The float 19 located in the dry control device 17 actuates a switch 21 when no more solvent condensate flows out of the cold register 11. This switch 21 is connected to a control device 23. This control device 23 controls the circulating air flow during the entire drying process. For this purpose, it contains all the control electronics required for this. On the output side 3 of the drum 1 there is a temperature sensor 25, a pressure sensor 27 and a humidity sensor 29 in the air conveying path 5, each of which is connected to the control device 23. On the other hand, the control device 23 is connected to the throttle valve 9 and the heating register 13.

A contact water device 31 is arranged behind the dry control device 17, which is connected on the input side to the dry control device 17 via an access line 33 and on the output side to a discharge line (not shown here) to a clean tank for the solvent. Furthermore, the contact water device 31 contains a drain 35 for introducing contact water into the drum 1. A valve 37 is also introduced in the drain 35 of the contact water device 31. The control device 23 is connected on the output side to the valve 37 for control purposes.

Furthermore, a measuring device 41 is attached to the access door of the drum 1 in approximately the same plane of the axis of rotation 39 of the drum 1 for non-contact measurement of the temperature of the goods. This measuring device 41 is connected to the control device 23 in terms of control.

After the spinning process, the drying process begins in the dry cleaning machine. The air flow is moved in the direction of the arrow by the blower 7 located in the air conveying path 5. On the output side 3 of the drum 1, the temperature, the pressure and the humidity in the air flow are measured in each case via the temperature sensor 25, the pressure sensor 27 and the humidity sensor 29, and the measurement data are forwarded to the control device 23 via the corresponding control lines. The gas concentration of the solvent in the air stream is determined in the control device 23 by the values of temperature, pressure and air humidity and, depending on this, the throttle valve 9 is actuated via the corresponding control lines by opening or closing it in a controlled manner so that the air volume flow is reduced or increased . If the gas concentration of the solvent in the air flow falls below a certain predetermined value, the control device 23 switches off the heating register 13 via the corresponding control line, so that the drying process is ended.

During the drying process, the solvent condenses at the entrance to the cold register 11 and, together with the amount of water which arises during the drying process of the goods, is drained off into the drying control device 17 and initially collected there. The float 19 located in the dry control device 17 reaches a certain level. The switch 21 is actuated when no more solvent condensate flows from the cold register 11. This switch 21 then sends a signal via its associated control line to the control device 23, which receives this signal and stores it for further control processes.

On the basis of the values determined by the sensors 25 to 29 via the corresponding control line, the control device 23 actuates the valve 37, which opens in order to supply the water 45 accumulated in the contact water device 31 to the drum 1 via the discharge line 35 when the moisture content of the Goods decrease while the temperature of the goods increases. The rise in the temperature of the goods is measured without contact by the measuring device 41 and the determined value is forwarded to the control device 23. On the basis of these measured values, the control device 23, as mentioned above, controls the throttle valve 9 or the heating register 13.

The present invention e.g. The drying process of a dry cleaning machine is optimized over the entire duration of the drying process in order to achieve a low solvent concentration of less than 280 ppm on the output side of the drum, as a result of which the drying time is shortened considerably and an environmentally friendly drying process is carried out.

Claims (10)

Process for the treatment of textile goods during the drying process in dry cleaning machines, washing machines, tumble dryers and similar devices, as well as in special devices for chemical surface treatment of textiles that use a circulating air flow and a solvent, or devices that only use water and therefore no Remove solvents and in which the air flow is circulated or open and those which have a heating register, characterized in that the temperature or the humidity of the surface of the textile goods is measured without contact and, depending on the measured values, the air flow, the air temperature or the moisture is influenced during the drying process. A method according to claim 1, characterized in that the air volume flow and / or the air temperature is continuously changed depending on the non-contact temperature or humidity on the surface of the goods and depending on the gas concentration of the solvent in the air flow, the gas concentration of the solvent at least determined from the temperature and pressure of the air flow on the outlet side of the drum and the temperature on the inlet side of the drum is reduced if the temperature on the outlet side of the drum or on the surface of the goods exceeds a predetermined value. Process according to claims 1 and 2, characterized in that in addition to the temperature and the pressure on the outlet side of the drum, the air moisture content is measured. Method according to claims 1 to 3, characterized in that the heating register is regulated and switched off as a function of the temperature or humidity of the surface of the goods by means of a control device when the gas concentration of the air flow drops below a predetermined value in order to end the drying process. Method according to claims 1 to 4, characterized in that the amount of water obtained in the air flow during the drying process from the Goods are collected and returned to the drum in gaseous form when the moisture content of the goods drops below a specified value. Device, in particular a chemical cleaning machine, washing machine, tumble dryer or similar device for carrying out the method according to claim 1, which uses a circulating air stream and a solvent, or a circulating or an open air stream, and a drum for receiving the goods, a heating register, a Control device and optionally a blower and a cold register, characterized in that a measuring device (41) for contactless measurement of the surface temperature or the moisture of the goods is arranged in the area of the drum (1), which is in operative connection with the control device (23), which, depending on the measured values, continuously regulates the air flow, the air temperature or the humidity during the drying process by means of a throttle device (9) located in the air conveying path (5), which between the output side of the drum (1) and the input side of the cold register rs (11) provided fan (7) is arranged. Apparatus according to claim 6, characterized in that the measuring device (41) is attached to the loading and unloading door of the drum (1). Device according to claims 6 and 7, characterized in that the measuring device (41) is mounted essentially in the plane of the axis of rotation (39) of the drum (1). Device according to claims 6 to 8, characterized in that a temperature sensor (25), a pressure sensor (27) and / or a moisture sensor (29) are arranged on the outlet side of the drum (1) and are connected to the control device ( 23) are connected. Device without a drum, in particular special devices for chemical surface treatment for carrying out the method according to claim 1, characterized in that a measuring device (41) is used for the contactless measurement of the surface temperature of the goods, via which, depending on the measured values, the air volume flow, the air temperature or the humidity can be influenced during the treatment of the goods.

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