EP3601916A1

EP3601916A1 - Dryer for a textile material web having a device for determining the residual moisture of a material web and method, module, and system therefor

Info

Publication number: EP3601916A1
Application number: EP18705892.0A
Authority: EP
Inventors: Markus Böhn; Andreas RÖSNER
Original assignee: Truetzschler GmbH and Co KG; Reifenhaeuser GmbH and Co KG Maschinenenfabrik
Current assignee: Truetzschler Group SE
Priority date: 2017-03-30
Filing date: 2018-02-15
Publication date: 2020-02-05
Anticipated expiration: 2038-02-15
Also published as: MX2019010413A; AR111552A1; BR112019018131A2; EP3601916B1; DE102017106887A1; RU2721390C1; US11125501B2; CN110382983A; WO2018177648A1; CN113483552B; CN110382983B; BR112019018131A8; US20200033059A1; ES2972596T3; CN113483552A

Abstract

The invention relates to a dryer (1) for a textile material web (5) having at least one dryer chamber (2), in which at least one air-permeable drum (3-3c) is rotatably arranged, which can be entwined at least in part by the material web (5) and wherein heated drying air can flow through the material web (5), and wherein there is at least one ventilator (17) by means of which moist drying air can be suctioned from the inside of the drum (3-3c) from an opening in the end face of the at least one drum (3-3c) and discharged by means of a duct (14) as exhaust (13). The dryer (1) has at least one sensor for determining the moisture of the exhaust flow, the data of which is processed in a controller (30) together with the starting moisture of the material web (5) and the moisture of the fresh air flow and the evaporating power of the dryer (1) is thus regulated. The invention further relates to a method, to a module, and to a system for determining the residual moisture of a material web continuously running through a dryer.

Description

Dryer for a textile web with a device for determining the residual moisture of a web and method, module and system for this purpose

description

The present invention relates to a dryer for a textile web with at least one dryer space in which at least one air-permeable drum is rotatably arranged, which is partially wrapped by the web and wherein the web is heated with heated drying air, wherein at least one fan is provided with from the front side opening of the at least one drum moist drying air from the inside of the drum is sucked.

DE 10 2012 109 878 B4 discloses a dryer for a textile web with a dryer space in which a plurality of air-permeable drums are rotatably arranged, which are partially wrapped by the web. The web is traversed by heated drying air, which absorbs the moisture from the web. Each drum is associated with a fan with which moist drying air is sucked from an opening of the drum from the inside of the drum. Heat is supplied via a circulation of the drying air and the heated drying air is returned to the dryer room.

For heat input, which is necessary for heating the drying air, serve heating elements, which are arranged in the heating and fan room. The heating elements are arranged so that they are flowed around by the air flow of the fan radially or tangentially flowing drying air. For example, are three drums provided to the the textile web is guided around one after the other, so three at least partially separate drying air circuits are provided, and each drying air circuit is generated by an associated fan. In this case, each heating air circuit own heating elements are assigned, so that the heat is supplied separately in each drying air circuit.

If the textile material web runs over an inlet roller and wraps around the drums one after the other, then the drying of the textile material web occurs stepwise one after the other. The removal of the moisture of the textile web is not uniform in each dryer room and with a constant Trocknungsgradienten, but the textile web passes through a drying cascade with several dryer rooms, and the degree of drying of the textile web that leaves the dryer on a discharge roll again, should have a required Have residual moisture. The drying process is ideally carried out with a minimum energy input into the dryer, so that, for example, a residual moisture content of 8% in the textile web when leaving the dryer, so that the energy input via the heat and the operation of the fan should be minimal for the entire dryer.

This determination of the residual moisture is carried out according to the prior art by measuring the initial moisture content of the web when entering the dryer and by measuring the final moisture content of the web when exiting the dryer. Known measuring methods of the final moisture of the web require a minimum moisture, it being assumed that the fibers of the web can absorb and store moisture. For fibers made of non-natural materials, such as spunbonded fabric, continuous filaments or staple fibers made of plastic, these can not store moisture, but absorb moisture through adhesion. Accurate measurements in the range of A maximum of 1% specific moisture is therefore not possible, especially not if the web has very low basis weights, for example in the range of 10 g / m ² . The fact that the fibers can not absorb and store moisture, the measurement is further difficult and thus inaccurate. With regard to the measurement accuracy to be achieved with a continuously moving web, the available measuring devices are disproportionately expensive.

The object of the invention is the development of a dryer for drying a textile web and the development of a method for operating such a dryer, wherein the dryer and the method to allow drying of the textile web with the least possible use of energy. In this case, the residual moisture of the web should be determinable and the dryer with its drying performance to a certain residual moisture adjustable. It is another object of the invention to provide a cost-effective module for retrofitting to a dryer, with the residual moisture of a web can be determined with sufficient accuracy. Finally, it is an object of the invention to provide a plant for the production of a spunbonded fabric, with which the residual moisture of the web after the drying process is adjustable.

This object is achieved starting from a dryer according to the preamble of claim 1 and starting from a method according to the preamble of claim 7 with the respective characterizing features. Advantageous developments of the invention are specified in the dependent claims. The provision of a module for retrofitting to a dryer is achieved with the features of claim 12. The system according to the invention is claimed in claim 15. The invention includes the technical teaching that the dryer has at least one sensor for determining the humidity of the exhaust air stream, whose data is processed in a controller with the initial moisture of the web and the moisture of the fresh air stream and thus the evaporation performance of the dryer is controlled.

The core idea of the invention is the approach to determine the determination of the residual moisture in the web via a consideration of the mass balance in a controller. The volumetric flow rate of the exhaust air and its specific humidity are used to calculate the evaporation rate of the drying process in the control system. The difference between the amount of water introduced into the process (initial moisture content of the web and initial moisture content of fresh air) and the evaporation rate of the dryer (moisture of the waste air) results in the remaining amount of water in the web. Furthermore, disturbances in the control can be processed.

For this purpose, the dryer preferably has at least one sensor in addition to the controller in the duct for the exhaust air, with which the temperature, the volume flow and the humidity of the exhaust air are determined. From the humidity of the exhaust air (absolute or relative), the initial moisture content of the web and the moisture of the fresh air stream are subtracted to determine the residual moisture of the web. Since the required evaporating power of the dryer can be determined via these parameters, the energy requirement of the dryer can conversely be minimized with a predetermined residual moisture since the heating power and / or the extracted volume of the exhaust air flow can be set via the controller. In contrast to the prior art, a simple and inexpensive sensor system can be used in which the continuous process does not have to be interrupted due to sampling. In a preferred embodiment, the sensor for determining the volume of the exhaust air on a measuring orifice, or is formed after the vortex flow measurement. Both variants allow for this application, a particularly reliable, sufficiently accurate and inexpensive measuring instrument. As a further alternative, an ultrasonic volume flow measurement can be used and / or the characteristic curve of the fan can be used for the evaluation

The temperature, mass flow and moisture of the web can also be determined via at least one sensor located on or in front of the dryer. This can be, for example, the kissroll and / or the batching station, in which the lubricant is mixed with water. As an alternative to the sensor, the absolute or relative humidity of the web can be determined on the basis of existing parameters from system components, which are arranged in the direction of the web before the dryer, and these data are entered into the controller.

Preferably, the controller has at least one process module and one energy module. The energy module interacts with the control of the at least one heating element and / or with the control of the at least one fan. In the process module, the mass balance of the humidities is calculated. In the event of a deviation from a reference variable of the desired residual moisture of the material web, the process module controls the energy module, which in turn determines the minimum energy requirement for an increased or decreased drying performance and optionally controls the heating elements and / or the fans.

The method according to the invention is characterized at least by the steps: Determination of at least the temperature and the humidity of the fresh air,

Determination of the temperature, volume and humidity of the exhaust air,

Determination of at least the mass flow and the moisture of the material web entering the dryer,

Input of a reference variable for the desired residual moisture of the web into a controller,

Offsetting of previously determined values in a controller and in the event of deviation from the reference variable Control of the heating elements and / or the fans taking into account a minimum total energy required.

The method according to the invention is based on the recognition that the evaporation performance of the dryer can be minimized by considering the mass balance of the moisture introduced into the dryer. In particular, with a set residual moisture of the web, which is calculated exclusively and not measured, can be dispensed with the necessary according to the prior art radiometric measurement of the continuously moving web after the dryer. The method can be operated with a minimum of inexpensive sensor technology. Especially for low weight webs of fibers (e.g., spunbonded webs) that can not store moisture, this method is particularly suitable for accuracy.

Preferably, the determination of the humidity and temperature of the fresh air with the same sensors, which also provide the data for the exhaust air. For this purpose, an empty drive of the dryer without activated heating elements and without web is required because the ambient air in the production hall does not change constantly. So that is the humidity and temperature of the ambient air of the dryer determined, which draws its fresh air from the environment (production hall). On this set of sensors that would otherwise be located at the inlet of the dryer, where the fresh air is attracted, can be dispensed with. The volume of fresh air required to calculate the mass balance is ultimately determined by the fan power of the dryer. In a first approach, it is first assumed that the amount of fresh air is equal to the amount of exhaust air. If it is known, depending on the design of the dryer, that even dead air has a significant influence on the mass balance, then the volume of fresh air during idling must also be measured, so that the volume of false air is taken into account in the consideration of the disturbance variable. The measurement of the volume of fresh air can then also be measured via the sensor for determining the exhaust air in the duct for the exhaust air.

The exhaust air is also monitored by sensors with regard to temperature, volume flow and humidity. These values are, in addition to the values for the mass flow and the moisture of the web, the most sensitive measured values of the process. Therefore, for example, the volume flow is determined by the accurate and inexpensive flow measurement, or alternatively by vortex flow measurement or other methods.

The determination of the mass flow and the moisture of the material web entering the dryer can take place by means of sensors, or can be determined by calculation or be carried out on the basis of the operating data of an upstream system component, for example the kiss roll and / or the batch station. In particular, the mathematical determination or the use of the operating data of an upstream system component can increase the accuracy of the process and make this cheaper, as for example, back to a radiometric method for determining the moisture of a continuously running web can be dispensed with. The further advantage lies in the application at low humidities and low basis weights of the web, since here the arithmetic process can be more accurate than the known measuring methods.

Preferably, known disturbances such as false air at the dryer, uneven Avivagen and / or fluctuations in the humidity over the working width of the web are entered into the controller and processed.

The module according to the invention for use on a dryer for determining the residual moisture of a dried web, comprises a controller with at least one process module for calculating the mass balance of the specific or relative humidity of the fresh air, exhaust air and the web, an energy module for controlling at least one heating element and at least a fan, with sensors to determine the temperature, humidity and volume flow of the fresh air and the exhaust air of the dryer. This creates a low-cost retrofit module that can be used to retrofit existing dryers with a continuously running web. Expensive radiometric measuring devices after the dryer or expensive sampling on the web can be dispensed with.

The module can preferably be supplemented by sensors for determining the temperature, the mass flow and the moisture of a continuously running web when process data from plant components in the direction of the web before the dryer are not available.

For processing disturbance variables, the module can have an interface or an input device. Preferably, the dryer according to the invention, the method and the module for equipment for the production of plastic webs, continuous filaments such as spunbond or staple fibers of non-natural fibers are used, which can not store moisture in contrast to webs of natural fibers.

Further, measures improving the invention will be described in more detail below together with the description of a preferred embodiment of the invention with reference to FIGS. Show it:

Figure 1: A perspective view of a

Series dryer;

Figure 2: A sectional view of another dryer

with a drum;

Figure 3: A schematic representation of the mass balance

the dryer;

FIG. 4 shows a control method of the drying process;

Figure 5: A plant for the production of spunbonded web.

1 shows a perspective view of a dryer 1, which is designed as a row dryer. Within a dryer room 2, three drums 3a, 3b, 3c are arranged one behind the other and with their axes 4a, 4b, 4c in a row. A web 5 is guided into the dryer space 2 via an inlet 6. About a guide roller 7 is the

15 web 5 only below the first drum 3a, then guided above the second drum 3b and then below the third drum 3c. Via a guide roller 8, the web 5 is led out through an outlet 9 from the dryer room 2. During the passage through the dryer room 2, the web 5 is heated

20 drying air flows through. The drying air takes the Moisture of the web 5 and is sucked through the interior of the drums 3a to 3c.

To the dryer room 2, an additional chamber 10 may be arranged, in which the channel 12 for the fresh air 1 1 and the channel 14 open for the exhaust air 13. The additional chamber 10 can be completely separate and constructed separately from the dryer room 2. At the additional chamber 10 of the heating and fan room 22 is arranged. The dryer room 2 is connected to the heating and fan room 22 with air ducts above and below the drums 3a-3c. The additional chamber 10 is connected via the frontal opening of the drums 3a - 3c with the dryer room 2. The duct connection 15 can be used as a connection for a heat exchanger. In this embodiment, sensors 18, 19, 20 for determining the temperature, the volume flow and the humidity of the exhaust air 13 are arranged in the channel 14. The moisture of the web 5 can be determined in the region of the inlet 6 on or in front of the dryer 1 by means of sensors 23, 24, 25, wherein here too the temperature, the mass flow and the moisture of the web 5 can be determined.

FIG. 2 shows a dryer 1 with only one drum 3, in which the material web 5 enters the dryer 1 from the right through an inlet 6. By a first guide roller 7, the web 5 is passed into the dryer room 2, guided around the drum 3 and led out through the guide roller 8 from the dryer room 2. The fresh air 1 1 is sucked through the inlet into the dryer 1 and distributed laterally below the drum 3 in the entire dryer room 2. An unillustrated shielding ensures that the sucked fresh air is not sucked directly into the drum 3. A heating element 21, for example a burner, heats the sucked-in fresh air, which is drawn in by a fan 17 on an end face of the drum 3. The heated fresh air flows through due to the generated by the fan 17 Pressure difference first, the screen cover 16, with which the flow is made uniform. Subsequently, the heated fresh air flows through the drum 3 with the wrapping web 5, and thereby absorbs the moisture of the web 5 on. The resulting exhaust 13 is discharged via the channel 14.

The determination of the residual moisture in the web 5 is carried out according to the invention by considering the mass balance in a controller. About the mass flow of the exhaust air 13 and their specific humidity in the control of the evaporation rate of the drying process is calculated. The difference between the amount of water introduced into the process (initial moisture content of the web and initial moisture content of fresh air) and the evaporation rate of the dryer (moisture of the waste air) results in the remaining amount of water in the web.

For this purpose, 13 sensors 18, 19, 20 are mounted in the channel 14 for the exhaust air, which measure the temperature, the air volume, and the humidity of the air stream. The values for the initial moisture content of the fresh air 1 1 can be measured with the same sensors 18, 19, 20 as the values for the humidity of the exhaust air 13. Here, before starting the dryer 1 via the fan 17 with the heating element switched off and the material web not introduced 5 fresh air sucked 1 1 and measured by the sensors 18, 19, 20. The measured values serve as zero point or reference for the mass balance. Only in the case of large deviations in the temperature or humidity in the system hall, this measurement must be repeated under the same conditions. If a gas burner is used as the heating element 21, it additionally introduces water into the drying process as a result of the burning process. This water content is taken into account via the gas consumption in the calculation of the final moisture content. The required values for the initial humidity of the fresh air 1 1 but also from the Ambient air of the dryer 1 are determined, since the fresh air 1 1 is sucked from the environment of the dryer 1. Taking into account that no appreciable proportion of false air is to be considered, the volume of fresh air 1 1 is determined by the fan power.

The humidity of the exhaust air 13 is also measured via the sensors 18, 19, 20 in the channel 14. The sensor 18 detects the temperature in degrees Celsius, the sensor 19, the volume flow of the exhaust air 13 in m ³ / h and the sensor 20, the humidity of the exhaust air 13 in kg / m ³ . Possible pressure differences between the exhaust air 13 and the fresh air 1 1 can be neglected in the mass balance. In this case, the volume flow of the exhaust air 13 is normally equal to the volume flow of the fresh air sucked 1 1, since false air through the web 5 and the drum 3 - 3c is sucked through the channel 14 by the suction power of the fan 17.

In the web 5 also the input moisture can be measured, which enters the dryer 1, for example, by a sensor 25 is arranged to measure the moisture in front of the inlet 6 of the dryer 1, or on a upstream plant component, such as a kiss roll or a pair of nip rolls , Alternatively, the input moisture can also be determined indirectly by a parameter from the process in front of the dryer, for example by the liquid consumption of a kiss roll or from the difference between liquid entry into the web and the discharge of residual liquid into a treatment plant. In particular, in the case of a kiss roll or a padder arranged in front of the dryer 1, the application to the lubricant or liquid can be determined by means of level sensors. Since the mass flow rate and the basis weight of the web before the kissroll or the padder are known, so that the proportion of liquid and thus the specific humidity of the Web to be determined before entering the dryer. As a disturbance in this consideration, among other things, the evaporation and / or a waste or spray off when applying the liquid and the deflection of the web can be determined empirically and taken into account

The sensor 18 for measuring the temperature of the exhaust air 13 may be formed as a thermometer or work on the semiconductor effect. The output value can preferably be degrees Celsius in the control

Preferably, the sensor 19 for measuring the volume flow is designed as a flow sensor with a metering orifice. Alternatively, the vortex flow measurement can be used, which takes place according to the principle of vortex flow measurement. Alternative measuring methods can be carried out with ultrasound or a dynamic pressure probe. The output value may preferably be m ³ / h in the control. Of course, the sensors 18 and 19 can also be combined.

The sensor 20 for determining the moisture may be formed as a thin-film capacitive polymer sensor or as a ceramic sensor. As output value preferably kg / m ³ absolute humidity or the relative humidity in percent can flow into the control.

The moisture of the web 5 before the inlet 6 of the dryer 1 can also be determined by calculation, in which the liquid entry is entered into the web with the mass flow of the web into the controller. This method is very accurate and only useful if the web can absorb any liquid or only a small proportion (up to 1%). This is true, for example, for plastic webs, continuous filaments or staple fibers of non-natural fibers, in particular spun-bonded nonwoven, in which the moisture is not physically bound, but only through the surface of the fibers is carried. Alternatively, one or more ceramic sensors 25 may be used which determine their moisture by direct contact with the web. This is useful in webs of fibers that absorb moisture and can store (cellulose, fiber blends, cotton).

The sensor 23 for measuring the temperature at the inlet 6 of the dryer 1 can again be designed as a thermometer or work according to the semiconductor effect. The output value can preferably be degrees Celsius in the control

The mass flow of the web at the inlet 6 of the dryer 1 can again be determined by calculation from the system parameters or, alternatively, by a sensor 24, which works radiometrically, for example.

Of course, the values of the incoming web 5 can be at least partially measured in the dryer 1 for determining the mass balance and another part of the upstream system components can be determined or calculated. This depends on the system configuration and the available values.

3 shows in simplified form the mass balance Σ of the drying process in which a mass flow rh of the web 5 enters the dryer 1 with an absolute or relative humidity H2O and a mass flow rh of the web 5 comes out of the dryer 1 with an absolute or relative humidity H2O. Other process parameters that are processed in the dryer 1, the mass flow rh of fresh air 1 1 with an absolute or relative humidity H2O at a temperature T to be determined, and the mass flow of moisture H2O at an adjustable temperature T from the heating element 21 (gas burner ) or the heating and fan room 22. The mass flow rh is drawn off with exhaust air 13 an absolute or relative humidity H2O at a temperature to be measured T. Since the fan 17 generates a negative pressure in the dryer, but the arrangement of the sensors 18, 19, 20 takes place in the channel 14, where ambient pressure already prevails, the parameter pressure can be dispensed with since all measurements are taken at the same ambient pressure in the production hall.

For example, the false air of the dryer from the production hall, fluctuations in the application of the finish of the upstream padder or the kissroll and the possible evaporation or spray off, inaccuracies in the sensors and fluctuations in the input moisture of the web over the working width can be used as disturbance variables 26 in the calculation of the mass balance incorporated. The interference quantities 26 are usually determined empirically depending on the system configuration and can increase or decrease the imputed mass balance.

The device according to the invention and the associated method are particularly advantageous in the case of spunbonded nonwoven since spunbonded nonwovens, unlike, for example, cellulose, can not store any moisture and therefore have very low moisture values with correspondingly high inaccuracies. Cellulose, on the other hand, is almost never dry because the residues of the pulp present in the cellulose are hygroscopic and thus moisture is stored in the fibers. In the manufacturing process of spunbonded nonwovens are usually no water components before the kissroll or the padder in the fiber, since only surface water and capillary water is carried along with the web. In comparison with staple fiber fleece made of, for example, natural fibers, spun fleece carries very little water, which is hardly measurable. The inaccuracies of classical measuring methods have a very unfavorable effect and result in fluctuations in the measured values with which the dryer can not be operated stably. The method for determining the mass balance is significantly cheaper and less expensive with the sensor technology more reliable than the previously used measuring technology with which the final moisture content is measured on the moving web.

Finally, FIG. 4 shows a schematic view of the construction of the controller 30 in interaction with a dryer space 2 of the dryer 1, whereby only a single dryer space 2 is shown by way of example. The controller 30 is preferably an integral part of the dryer 1. But it can also be part of an overall system with which the process of manufacturing the web to the winding of the finished web is monitored and controlled on a subsequent winder.

The controller 30 may include a power module 31 and a process module 32. The power module 31 is designed to monitor at least the heat supplied by the heating element 21 and / or the fan 17.

The process module 32 is designed to process the measured values of the sensors 23, 24, 25 or the calculated values or determined values for the input moisture of the web 5 into the dryer. Furthermore, the process module 32 processes the measured values of the sensors 18, 19, 20 in the exhaust air 13. At the same time, the process module 32 also processes the interference quantities 26, which are input to the controller 30 in accordance with the system configuration and the material web to be processed. Instead of the sensor 25 for the moisture of the web 5 at the inlet 6 of the dryer 1, an imputed value for the moisture can also be entered into the controller 30, which is determined on the basis of an upstream system component such as a kissroll. The process module 32 can thus not only process direct measured values but also computational data or input values from the process upstream of the drier 1. The separation of the controller 30 in a process 32 and a Power module 31 allows the use and interconnection of the existing control of the heating element 21 and / or the fan 17 and the fan room 22 as an energy module 31, wherein the process module 32 may then be formed as part of a controller for the entire system. Within the process module 32, the mass balance Σ of the moisture is calculated.

With the inventively designed controller 30, the possibility is created that at a required residual moisture of the textile web 5 as it passes through the dryer 1, the heat through the heating element 21 and / or the fan 17 of the textile web traversed drying chamber 10 with the appropriate energy so that a minimum total energy requirement is achieved. Thus, with the power module 31, a control of the heat supply by the heating element 21 and the fan 17 is made so that the dryer room 2 is supplied with only a minimum required energy. In particular, a cost-optimized operation of the dryer can thus be achieved because the cost of electricity (fan 17, 22) are about four times higher than gas (burner, heating element 21) and the energy module 31 can be operated both energy-optimized and cost-optimized. Since many plant operators also have their own gas or electricity generation, energy-optimized operation of the dryer can deviate from cost-optimized operation. The control provides the plant operator with the appropriate tool for selecting the best operating method for him.

An ideal drying process is achieved which achieves a drying air with an optimum proportion of superheated steam for the dryer room 2. In the event of a deviation (control deviation) from the predetermined residual moisture (reference variable) in the material web 5, the process module 32 activates the energy module 31, which in turn controls the heating power and / or the extracted air quantity either energy or cost optimized increased or decreased.

When the method for operating the dryer 1 with the controller 30 is carried out in the manner described above, a dryer 1 which adjusts itself with minimum energy is consequently created. The controller 30 of the dryer 1 ensures a minimum energy flow into the respective dryer room 2, so that the power consumption is minimized to achieve the required residual moisture of the textile web 5. The respective operating states are dependent on the quality and the input moisture of the textile web, so that for example via a control panel of the dryer 1 empirical values can be entered, which control values for air conditioning of the individual dryer rooms 2 are necessary. These values depend, for example, on the quality, the density, the weight per unit area and the thickness of the textile web 5, preferably also the input moisture and initial moisture content of the textile web 5 being taken into account as an input for programming the controller 30 and for running a corresponding dryer program of the dryer 1 become.

The embodiment relates to a dryer with a drum 3. The control of the heating elements 21 or the fans 17 and the fan room 22 can be done separately in a row dryer for a dryer room 2 with several drums 3 - 3c, since the moisture absorption of the dryer air from the first drum 3 to the last drum 3c decreases.

It can be seen that only the web 5 entering the dryer 1 is monitored for its values of temperature, mass flow and moisture by means of sensors or determined values. Also, only the exhaust air 13 is monitored for its composition. by virtue of the mass balance of the dryer 1 is controlled so that the expiring from the dryer 1 web 5 no longer needs to be monitored in terms of their moisture.

The plant according to FIG. 5 schematically shows the production of a spunbonded nonwoven which is spun in a spinnerette made of thermoplastic material, not shown, cooled and deposited on a circulating conveyor belt 40 by means of a diffuser 41. The conveyor belt is preferably designed as an air-permeable screen belt to fix by a suction spunbonded on the conveyor belt 40 and simultaneously withdraw liquids from the subsequent treatments. A first pair of outfeed rollers 42, which may possibly be heated, can compact the deposited spunbonded nonwoven fabric. After a first moistening 43 by a spray bar, with which the uniform deposition of the spunbonded fabric on the conveyor belt 40 is favored, as this the individual filaments are better fixed, there is a first suction 44 of the applied liquid. A first solidification 45, for example by means of water jets, can solidify and compact the web 5 of spunbonded nonwoven. Again, excess water is sucked through a suction 44. A subsequent treatment device 46, for example a kissroll or a padder, apply a treatment liquid to the web 5. As a treatment liquid, a finishing agent can be used with which the properties of the spunbonded fabric with respect to the end product is improved. Subsequently, the web 5 passes through a dryer 1, which is designed in this embodiment as an omega dryer with a drum 3. In this case, the web 5 is set to a predetermined residual moisture, in which the evaporation rate of the dryer 1 is adjusted and fed to the passage of the dryer of a further treatment or a winding process. In In this embodiment, fresh air 1 1 is supplied to the dryer, the moisture content of which is determined from the environmental data or by a blank measurement of the dryer 1. In the channel 14, the humidity (volume flow, temperature, humidity) of the exhaust air 13 is determined by means of sensors. The moisture content of the incoming material into the dryer 1 web 5 can be calculated, measured by sensors before the inlet of the dryer or determined based on the process parameters of the treatment device 46 and entered into the controller 30. The plant configuration shown here is exemplary and may have further or no solidification 45 for the treatment of the spunbonded web. Likewise, the system can be supplemented with other components, or waived the moistening 43 after the filing of the spunbonded on the conveyor belt.

The invention has the advantage that for determining the residual moisture, the web is not impaired (cutting out of samples), which can pass through the web continuously and is not touched by measuring elements. The method is independent of the product properties of the web, which in a direct (touching) measurement can have a significant influence on the measurement result. Another advantage is that in comparison to gravimetric or volumetric measurement methods metrological influences of disturbances are eliminated, since these methods relate only to the water mass flow. Particularly in the case of spunbonded nonwovens, where the mass ratio between web and quantity of water is unfavorable or large, low final moisture content (<1%) can be reliably determined at low web weights (eg 10 g / m ² ) while the web is running. Since the invention determines without contact the residual moisture of the web, speeds of more than 500 m / min do not affect the accuracy. Another advantage is the regulation of the dryer for energy optimization, since at a given Residual moisture the dryer performance is adjusted. Compared to the previous measurement methods, the invention realizes a very inexpensive and sufficiently accurate solution, since no complex sensors must be used. The invention is not limited in its execution to the above-mentioned preferred embodiment. Rather, a number of variants is conceivable, which makes use of the illustrated solution even with fundamentally different types of use. All of the claims, the description or the drawings resulting features and / or advantages, constructive details or spatial arrangements may be essential to the invention both in itself and in various combinations.

reference numeral

1 dryer

2 drying room

3, 3a, 3b, 3c Tronnnnel

4a, 4b, 4c axis

5 web

6 inlet

7 guide roller

8 guide roller

9 outlet

10 additional chamber

1 1 fresh air

12 channel

13 exhaust air

14 channel

15 channel connection

16 screen cover

17 fans

18 sensor temperature

19 Sensor volumetric flow

20 sensor humidity

21 heating element

22 fan room

23 sensor temperature

24 sensor mass flow

25 sensor humidity

26 Disturbance

30 control

31 energy module

32 process module

40 conveyor belt

41 diffuser

42 exit rollers

43 humidification 44 suction

45 solidification

46 Treatment device Σ Mass balance Humidity m Mass flow

T temperature

Claims

claims

1 . Dryer (1) for a textile material web (5) with at least one dryer space (2) in which at least one air-permeable drum (3 - 3c) is rotatably arranged, which can be partially wrapped by the web (5) and wherein the web (5 ) with heated drying air is flowed through, wherein at least one fan (17) is provided with which from a front opening of the at least one drum (3 - 3c) moist drying air from the inside of the drum (3 - 3c) is sucked and exhaust air ( 13) by means of a channel (14) can be discharged, characterized in that the dryer (1) has at least one sensor for determining the humidity of the exhaust air stream whose data in a controller (30) with the initial moisture of the web (5) and the moisture processed the fresh air flow and thus the evaporation performance of the dryer (1) is controlled.

2. dryer (1) according to claim 1, characterized in that the at least one sensor for determining the humidity of the exhaust air flow determines the temperature, the volume and the humidity of the exhaust air (13).

3. dryer (1) according to claim 2, characterized in that the sensor (19) for determining the volume has a metering or is formed after the vortex flow measurement or is formed after the ultrasonic flow measurement.

4. dryer (1) according to claim 1, characterized in that on or before the dryer (1) sensors for determining the Temperature, the mass flow and / or the moisture of the web (5) are arranged.

Dryer (1) according to claim 1, characterized in that the controller (30) comprises a power module (31) and a process module (32).

Dryer (1) according to any one of the preceding claims, characterized in that the dryer (1) at least one heating element (21) and the controller (30) is designed such that at a required residual moisture of the textile web (5) on leaving the Trockners (1) the at least one heating element (21) and / or the at least one fan (17) are controlled so that the dryer (1) is optionally operated energy and / or cost optimized.

Method for operating a dryer (1) for a textile material web (5) with at least one dryer space (2), in which at least one air-permeable drum (3 - 3c) is rotatably arranged, which is partially wrapped by the web (5) and wherein the fabric web (5) is flowed through by heated drying air, and wherein at least one fan (17) is provided, with which moist drying air is extracted from the inside of the at least one drum (3 - 3c) from an end opening of the drum (3 - 3c) the method comprises at least the following steps:

- Determining at least the temperature and humidity of

Fresh air (1 1),

- Determination of the temperature, volume and humidity of the

Exhaust air (13),

Determination of at least the mass flow and the moisture of the material web (5) entering the dryer, - Entering a reference variable for the desired residual moisture of

Web in a controller,

- Compensation of previously determined values in a controller and at

Deviation from the reference variable Control of the 5 at least one heating element (21) and / or the at least one fan (17) with optional consideration of energy and / or cost optimization.

8. The method according to claim 7, characterized in that the i o determination of the humidity and temperature of the fresh air (1 1) in

Channel (14) before starting the dryer (1).

9. The method according to claim 7, characterized in that the determination of the moisture, temperature and the volume flow

15 of the fresh air (1 1) and exhaust air (13) by means of sensors (18, 19, 20).

10. The method according to claim 7, characterized in that the determination of the mass flow and the moisture of the web

20 (5) by means of sensors, or is determined by calculation or can be determined with the operating data of an upstream system component.

1 1. A method according to claim 7, characterized in that 25 disturbances (26) such as false air at the dryer, uneven Avivage the web, and / or fluctuations in the moisture content of the web over the working width in the controller (30) are input and processed.

30 12. Module for use on a dryer to determine the

Residual moisture of a dried web, comprising a controller (30) with at least one process module (32) for Calculation of the mass balance of the specific or relative humidity of the fresh air, exhaust air and the web, an energy module (31) for controlling at least one heating element and / or at least one fan, with sensors 5 (18, 19, 20) for determining the temperature, the Moisture and the volume flow of the fresh air and the exhaust air of the dryer.

13. Module according to claim 12, additionally comprising sensors (23, 24, 25) for determining the temperature, the mass flow and / or i o the moisture of a continuously moving web.

14. Module according to claim 12 to 13, comprising an interface or input device for input of disturbances.

15 15. System for the production of spunbonded nonwovens from endless filaments, in which spun from a thermoplastic continuous filaments in at least one Spinnerette, then cooled and deposited by means of a diffuser (41) on a conveyor belt (40), wherein the spunbonded by means of a moistening (43 ) and or

20 solidification (45) is pretreated, and after a

Treatment apparatus (46) is fed to a dryer (1), characterized in that the spunbonded fabric is dried in the dryer (1) to a predeterminable residual moisture, according to one of the preceding claims.

25

30