Textile treatment equipment and methods

Abstract

Textile treatment plant for the treatment, in particular dyeing, of textile substrates, comprising a device (100) for dosing a free-flowing substance to an aqueous treatment bath for the treatment, in particular dyeing, of a textile substrate, and a wet treatment container for receiving and treating the textile substrate, wherein the device comprises: a storage container (102) for the pourable substance, a mixing unit (104) which has an inlet (106) and an outlet (108) for the aqueous treatment liquor and a sprinkling opening (188) for the pourable substance, a controlled conveying system (114) connected to the storage container (102) for transporting the pourable substance from the storage container (102) to the spreading opening (188), and a control unit connected to the regulated conveying system (114), which is configured to output a control signal to the regulated conveying system (114), and wherein the wet treatment tank is connected to the inlet (106) and outlet (108) of the mixing unit (104) by means of a pipe connection in order to transfer the aqueous treatment liquor into the wet treatment tank.

Description

[0001] The invention relates to a textile treatment plant for the treatment, in particular dyeing, of textile substrates, comprising a device for dosing a substance to an aqueous treatment liquor for the treatment, in particular dyeing, of a textile substrate.

[0002] From German patent application DE 24 11 262 A1, a device for dissolving a swellable thickening agent in the production of printing inks, particularly in the textile industry, is known. The invention relates to the production of a homogeneous thickening solution with a predetermined viscosity, which is achieved by continuously subjecting the powdered thickening agent to a milling process under the influence of shear, compression, and decompression forces in a predetermined ratio with a liquid.

[0003] Document US 3,957,253 A deals with the handling of sodium hydrogen sulfide as a bleaching agent in textile processing. According to the document, it is first processed in a mixing tank with water and sodium hydroxide to form a stable solution, which can then be added to the treatment bath in liquid form.

[0004] Various dye systems are known to be used for dyeing cellulosic textiles, such as reactive dyes, direct dyes, or vat dyes. Cellulose exists in textiles in different forms. Examples include cotton, linen, jute, viscose, cupro, and similar fibers.

[0005] In all conventional dyeing processes used to finish cellulosic textiles and their blends, salt, particularly in the form of sodium chloride or sodium sulfate, is added to deliberately shift the concentration ratio in the dye bath, thereby increasing and controlling the dye's extraction rate onto the textile. The most common class of dyes used for cellulosic textiles today is reactive dye.

[0006] Dyes of this class require fixation on the textile, or a chemical reaction with it, after being extracted from the dye bath and applied to the fabric. This fixation is controlled by temperature and pH changes. The pH-modifying chemicals are typically sodium carbonate and sodium hydroxide. Often, these chemicals are used only to adjust the pH to the desired value. Some dye formulations contain pH buffers, which ensure that the desired pH value is maintained at a stable level.

[0007] The term "treatment liquor" refers to the liquid present in the dyeing system at any given time for treating the textile substrate. This includes, therefore, purified water at the beginning of the treatment and the finished dyeing solution after all components have been added and dissolved.

[0008] Suitable textile substrates include, in particular, thread-like, ribbon-like, or sheet-like substrates of finite length and in the form of an "endless" strand of fabric or a winding of fabric. These include loose fibers, textiles on yarn spools, hanks, and other textile products of any form in which cellulosic textiles may be present.

[0009] The following describes the dyeing process, which is well-known in itself, starting with the raw textile material. The entire dyeing process is essentially divided into three steps: pretreatment, the actual dyeing, and post-treatment. In particular, the pretreatment can also be carried out completely independently of the actual dyeing, for example, in a different system. Pretreatment

[0010] The cellulosic textile raw material is coated with natural waxes. These must be removed in an initial alkaline pretreatment step to enable the material to absorb water and, consequently, dye. Besides optimizing the material's wettability, this pretreatment step also causes the cellulose to swell, allowing it to absorb even more water. The pretreatment takes place at relatively high temperatures (85°C - 110°C). The alkaline pH is adjusted by adding sodium hydroxide. The waxes and oils on the cotton raw material are saponified and used as surfactants. In the resulting soap bath, these act as emulsifiers against coarse impurities on the material, thus improving the cleaning effect. This pretreatment ensures that the nuances in the inherent color and physical properties of different batches of cotton are as uniform as possible, enabling reproducible dyeing results.Additionally, the fabric is bleached with hydrogen peroxide, primarily to achieve lighter shades. This destroys the cotton's natural pigments, making the fabric appear whiter. At the end of the pretreatment, the pH value must be neutralized using an acid, usually a highly concentrated solution such as 66% acetic acid. The bleach must also be removed. These extensive rinsing processes are necessary to prevent any chemicals from being carried over into the subsequent dyeing process. coloring

[0011] The dyeing process itself consists of two functional steps: dye extraction (or migration) and fixation. In conventional processes using jet dyeing systems, dyeing takes place at a liquor ratio of at least 1:4, more often 1:5 to 1:6 or higher. The liquor ratio is defined as the ratio of the mass of the textile substrate to be treated (in kg) to the volume of the required treatment liquor (in L). As is conventional practice, a liquor ratio with a comparatively higher volume of treatment liquor, for example, a liquor ratio of 1:6 compared to a liquor ratio of 1:5, is referred to as the "higher liquor ratio," contrary to the numerical notation. Depending on the desired color and its saturation, suitable quantities of salts (sodium chloride or sodium sulfate) are stored in containers at the system and fed from there into the dyeing unit.The salt is added either dry or partially dissolved to improve its transportability. In newer systems with dry salt feeding, the required amount of salt is held in a funnel-shaped container, which is completely emptied into the treatment bath by a vibrating motion. In conventional dyeing processes, the higher the desired color saturation, the higher the salt concentration must be during dyeing. This is because increasing the concentration of dissolved electrolytes in the form of sodium ions improves dye extraction during the reactive dyeing of cellulosic textiles. Once the desired salt concentration is reached, the pre-dissolved dye is added to the dye bath over a specific, extended period.As an alternative to the process described above, the treatment bath containing salt and dye can also be prepared in a mixing vessel and fed into the dyeing system. After the dye has been dosed or the entire treatment bath has been added, the goods are rotated in the dyeing system for a specific period, the so-called dye migration phase, to ensure that the dye-salt mixture is evenly distributed throughout the goods.

[0012] Once the dye has evenly adhered to the fabric, and the migration phase is complete, it must be fixed. With reactive dyes, this occurs through a chemical reaction between the dye and the functional groups of the cellulosic textile. The intensity or rate of this chemical reaction depends on the reactive dye, the functional groups (hydroxyl groups) of the cellulosic textile, the temperature, and the alkaline pH (pH > 7). For most reactive dyeing systems, an isothermal temperature profile is used during the migration and fixing phases. The alkalinity of the dye bath is slowly adjusted from neutral to a pH of approximately 11 by adding pre-dissolved sodium carbonate. Subsequently, liquid (33%) sodium hydroxide is usually added to the dye bath over an extended dosing phase. This slowly raises the pH to approximately 12.5 to 13.The reaction optimum for most reactive dyes lies within this pH range. Carefully increasing the pH value regulates the chemical reaction between the dye and the functional groups of the cellulosic textile, ensuring a uniformly distributed chemical reaction on the textile substrate and thus a consistent dyeing result. Another reason for regulating the dye's reactivity is that, under optimal conditions (temperature and pH), reactive dyes react with the solubility products of water (water → hydronium ions + hydroxyl ions) for fixation. This process is called dye hydrolysis. The hydrolyzed dye molecules are no longer available to react with the functional groups of the cellulosic textile and therefore cannot be used for the dyeing process. The hydrolysis reaction can be largely minimized by slowly increasing the pH value and controlling the temperature. Post-treatment

[0013] After the reactive dye has fixed, excess and hydrolyzed dye residues, as well as the dissolved salt, must be removed. The salt concentration in the textile is reduced by repeatedly rinsing the dyed fabric in warm water. The amount of salt used determines the number of these baths and the volume of water required. Water consumption can be reduced with the salt-free dyeing process described below. Once the salt has been removed, the textile, which is alkaline due to the sodium hydroxide treatment from the dyeing process, is neutralized using an acid, usually a highly concentrated acetic acid, such as 66%. Otherwise, the subsequent hot soap baths would partially remove the previously fixed dye and alter the color. The hot soap baths in a pH-neutral medium emulsify only the unfixed dye residues on the fabric, which can then be drained off.This process is primarily necessary to achieve demanding colorfastness properties (wash fastness, perspiration fastness, rub fastness) and is applied multiple times, especially for dark colors. This is followed by several warm rinses, typically two to three, to remove any remaining emulsified dye. The final rinse may contain a low concentration of acetic acid and, if necessary, a softener to give the dyed fabric a pleasant feel.

[0014] Recent developments aim to completely eliminate the need for salt when using particularly low dye bath ratios, meaning a higher proportion of textile substrate to treatment bath than previously possible. The international patent application WO 2014 / 155101 A1 serves as an example. One advantage of this development is the minimal water used in the dyeing process itself—both during the extraction of the dye from the dye bath onto the textile and during the fixation of the dye on the textile—and during the subsequent rinsing of the textiles to remove the salt.

[0015] Against this background, the purpose of the invention is to create a basis for environmentally friendly and economical dyeing on an industrial scale.

[0016] The problem is solved, among other things, by a textile treatment plant for the treatment, in particular dyeing, of textile substrates, comprising a device for dosing a bulk substance into an aqueous treatment bath for the treatment, in particular dyeing, of a textile substrate, and a wet treatment tank for receiving and treating the textile substrate, wherein the device has a storage tank for the bulk substance, a mixing unit comprising an inlet and an outlet for the aqueous treatment bath and a feed opening for the bulk substance, a controlled conveying system connected to the storage tank for transporting the bulk substance from the storage tank to the feed opening, and a control unit connected to the controlled conveying system, which is configured to output a control signal to the controlled conveying system.comprising and wherein the wet treatment tank is connected to the inlet and outlet of the mixing unit by means of a pipe connection in order to transfer the treatment liquor into the wet treatment tank.

[0017] In the broadest sense, a "wet treatment tank" refers to the part of a textile treatment system where the treatment liquor and the textile substrate to be treated are combined. In dyeing processes, the wet treatment tank is also called a "dyeing kettle." Such tanks are well-known, and their mechanical details are therefore not described here.

[0018] While conventional methods for fixing the dye to the textile involved adding sodium carbonate in liquid form, i.e., pre-dissolved, the invention enables the sodium carbonate to be added directly to the treatment or dyeing bath in a free-flowing form, such as granular or powdered form, by means of a device according to the invention that can be connected to the wet treatment tank of a textile treatment system and thus integrated into the treatment liquor circuit within the dyeing machine. With this method, also referred to herein as "dry dosing," pre-dissolving outside the dyeing bath is no longer necessary, thereby reducing water consumption while maintaining at least the same level of dosing accuracy.

[0019] It is known that sodium carbonate is hygroscopic. Sodium carbonate and hygroscopic substances in general therefore tend to clump together upon contact with moisture. Since they already contain water in this state, a small portion of the substance may be dissolved at the surface. However, the vast majority of the substance remains in the solid state. Even in this state, the substance is "poundable" within the meaning of the invention. The term "poundable" generally refers to both cohesive and cohesive bulk materials. In addition to largely undissolved substances, the term "poundable" also includes, in particular, powdered or granular substances. Synonymous terms used here are "solid," "dry," and "in a solid state." The substance in this form can also be described as bulk material.

[0020] Especially in novel or future dyeing processes for purely cellulosic textiles or textile fiber blends with a cellulosic component, which help to reduce the addition of salt, the device according to the invention can be used in the described manner for the dry dosing of sodium carbonate in order to further reduce the water requirement in a practical way and to achieve a lower liquor ratio. With decreasing water content, i.e., increasing dye concentration, precise dosing is generally essential, which is ensured by dry dosing.

[0021] This is just one possible application example where water can be saved using the dosing device according to the invention. The device can also be used, in particular, to retrofit conventional or existing dyeing machines, including those where the dye extraction takes place with the addition of salt, to save water. Specifically, the dosing device according to the invention can also be used for adding the salt itself to the treatment liquor, thus eliminating the need for pre-dissolving in this process step and thereby reducing water consumption. Furthermore, the device also allows mixtures of salt and sodium carbonate to be dosed dry.

[0022] Although the dyeing process described above and in the following description of preferred embodiments represents a primary application of the present invention, its application is not limited to this. The invention can be used in many other areas of textile finishing. For example, the device can be used to add sodium hydroxide in the form of flakes as a free-flowing substance in a controlled manner during pretreatment.

[0023] In general, the device according to the invention is therefore not limited to dyeing, but can be used to supply any free-flowing chemicals for the treatment or finishing of a textile substrate in order to save water. The dry dosing system according to the invention ensures reproducible dosing curves due to the controlled transport of free-flowing chemicals and enables high-quality, uniform, and reproducible dyeing results.

[0024] Various mechanical or pneumatic feeding devices, such as vacuum conveying systems like Venturi tubes, can be used as controllable conveying systems. In the latter, the liquid treatment solution is forced through a nozzle assembly to create a vacuum, with a control valve regulating the flow rate of the treatment solution. The flow rate of the treatment solution influences the pressure in the volume surrounding the nozzle assembly. Depending on the setting of the control valve, the dry substance being added is drawn from a reservoir connected to the volume, thus being dosed in a controlled manner.

[0025] Preferably, the conveying system includes a screw conveyor designed to transport the loose material from the storage container to the dispensing opening. The screw conveyor is part of a mechanical conveying system that is particularly simple and precisely controllable.

[0026] The conveying system advantageously has a controllable drive connected to the control unit (for example, for the screw conveyor).

[0027] Preferably, the storage container or conveying system includes a measuring unit for determining the quantity of the bulk substance contained in or withdrawn from the storage container. In both cases, the quantity of the bulk substance added can be determined directly or indirectly. In particular, this can be a gravimetric measuring unit for measuring the mass or a volumetric measuring unit for measuring the volume of the substance withdrawn or contained in the storage container. A volumetric measuring unit can, for example, be provided by an ultrasonic or laser measuring device for determining the fill level of the substance in the storage container or the flow rate of the substance through the conveying system, or by an associated connecting piece at a suitable measuring point.

[0028] Preferably, the measuring unit is a weighing unit configured to determine the mass of the bulk substance contained in the storage container. This is a gravimetric measuring unit. The weighing unit can be implemented using load cells arranged on the storage container, which monitor the total mass of the storage container in real time and, consequently, the mass of the bulk substance conveyed to the mixing unit within a specific unit of time.

[0029] Particularly preferably, the measuring unit is connected to the control unit and configured to output a measured quantity, i.e., the measured quantity (mass or volume) of the extracted or contained bulk substance, as a control variable to the control unit, and the control unit is configured to vary the control signal to the conveying system, in particular to the controllable drive, depending on the measured quantity, for example to increase or decrease the conveying flow as required.

[0030] For this purpose, the control unit can be connected to an internal or external storage device and / or an input terminal, either locally or remotely, and configured to query parameters from the storage device and / or the input terminal. These parameters are stored, for example, in the form of a pre-programmed dosing profile (quantity-time diagram). These parameters serve as setpoints and, together with the measured or controlled variable output by the measuring unit, can be processed into control signals for the controllable drive.

[0031] If, in the example described above, the measurement or monitoring by the load cells shows that the conveying rates deviate from a target value, the control unit can adjust the frequency of the screw conveyor during dosing until the dosing is back within the target range.

[0032] The desired low water volume leads to a higher concentration of additives (dyes, salts, sodium carbonate, sodium hydroxide) in the treatment bath. The invention takes into account the observation that even slight fluctuations in the concentration of additives have a more noticeable effect on the dyeing result than with a higher bath ratio. Therefore, especially with dry dosing, it is necessary to keep the added quantities within narrow limits, for which the measuring unit, in conjunction with the control system and the conveying system, provides the basis.

[0033] Alternative or additional parameters or control variables besides the quantity of powdered or granular substance dispensed and a dosing profile can include, for example, the fill level or conductivity of the treatment solution. These can be determined within the device or elsewhere in the textile treatment system, i.e., outside the device, and then fed to the control unit. For example, the fill level of the treatment solution can be measured directly in the wet treatment tank of the textile treatment system, or the conductivity of the treatment solution can be measured in the main circuit of the wet treatment tank. Other parameters to consider include the dosing duration, the total dosage, physical or chemical properties of the treatment solution (e.g., conductivity), and the respective setpoints, among others.

[0034] Controlled dosing is also advantageously achieved if the storage container includes an agitator designed to keep the free-flowing substance in motion. Such an agitator ensures that, especially with substances prone to clumping, no voids form in the storage container, the fill level remains consistent, and the substance completely covers the bottom of the container. Furthermore, the agitator preferably has a geometry that facilitates the transport of the substance within the storage container towards an outlet opening connected to the conveying system. Through these measures, the agitator ensures continuous discharge from the storage container, even with substances that are not free-flowing.

[0035] According to an advantageous embodiment of the invention, the mixing unit comprises a pre-dissolving vessel with an inlet for the treatment solution, wherein the inlet is fluidically connectable to the feed and opens into the pre-dissolving vessel in such a way that the treatment solution introduced via the inlet circulates within the pre-dissolving vessel. This can be achieved, for example, by a pre-dissolving vessel with a round inner contour, wherein the inlet opens as tangentially as possible to the inner contour. Alternatively, instead of a pre-dissolving vessel with a tangential inlet, a pre-dissolving vessel with a magnetic stirrer can also be provided to generate circulation of the treatment solution.

[0036] Preferably, the dispensing opening is arranged above a section of the treatment solution circulating in the pre-dissolving tank. The free-flowing substance to be dosed is transported from the storage tank to the dispensing opening by means of the conveying system and falls from there, driven by gravity, into the dye solution circulating in the pre-dissolving tank. Due to the movement of the dye solution, shear forces act upon it, which quickly ensure a homogeneous distribution of the solid substance. Preferably, one or more sieves are located in the dispensing opening, which counteract agglomeration or clumping, particularly in the case of powdered substances, which would otherwise be promoted by the conveying process.

[0037] Preferably, the pre-dissolving vessel has a bottom outlet, and the mixing unit below the pre-dissolving vessel has an injection unit that is fluidically connected to the outlet of the pre-dissolving vessel. Particularly preferably, the bottom of the pre-dissolving vessel is designed to taper towards the outlet in a funnel shape. This ensures that the treatment solution containing the added solid substance flows from the pre-dissolving vessel into the injection unit largely without residue. Since the solid substances in question usually do not dissolve completely in the treatment solution during the relatively short residence time in the pre-dissolving vessel, a mixture of solid and liquid phases exits through the outlet.

[0038] Advantageously, the injection unit has a discharge volume that is fluidically connected to the outlet of the pre-dissolving tank. Within this discharge volume, an injector nozzle, fluidically connected to the inlet of the mixing unit, is arranged to generate a directed flow of the treatment solution within the discharge volume. This creates a hydrostatic pressure at the injector nozzle's outlet that is reduced compared to ambient pressure, based on the principle of a Venturi tube. This pressure draws in the mixture flowing from the pre-dissolving tank and carries it along with the flow. Shear forces occur again during this process, further homogenizing the mixture. This constitutes a two-stage mixing process.

[0039] The discharge volume is connected to the outlet of the mixing unit. In this way, the treatment solution can be returned to the textile treatment system's circulation after dosing.

[0040] To generate the directed flow of the treatment solution, the device preferably has a pressure pump between the inlet of the mixing unit and the injector nozzle. The pressure pump is preferably connected to the control unit.

[0041] According to an advantageous embodiment, the device comprises a liquid reservoir for a liquid to be added to the staining solution and a supply line fluidically connecting the liquid reservoir to the mixing unit (in the embodiment described above, to the pre-dissolving tank), into which a liquid dosing device is integrated. This arrangement can be used, for example, for dosing pre-dissolved sodium hydroxide. The liquid is introduced into the pre-dissolving tank and, driven by gravity, into the circulating treatment solution. Advantageously, the supply line opens above a section of the treatment solution circulating in the pre-dissolving tank. In this way, the liquid is also homogeneously distributed in the treatment solution by the two-stage mixing process.In this way, the device can be combined with liquid dosing systems without an additional pressure pump to create a cost-effective dosing system. Precise dosing is essential here as well, and suitable dosing devices for liquids are known in dyeing technology. The liquid dosing unit consists of a dosing valve. The dosing valve itself can be adjustable and connected to, or connectable to, the control unit.

[0042] The wet treatment tank can be connected directly or indirectly to the inlet and outlet of the solvent tank in order to transfer the treatment solution, in relation to the flow direction, before dosing into the wet treatment tank.

[0043] In this way, the device is integrated into the treatment liquor circuit. "Directly or indirectly connectable" in this context means that a pipeline connection exists between the wet treatment tank and the device, possibly with the interposition of further elements of the textile treatment system such as pumps, heating devices, or the like, which can be opened or closed selectively by means of valves.

[0044] Preferably, the control unit is part of a programmable logic controller (PLC), in particular a programmable logic controller (PLC), of the textile treatment system. This simplifies the control-related integration of the device with the textile treatment system. In particular, this allows additional parameters within the textile treatment system, such as fill level or conductivity measurements, to be used for controlling or regulating the device. For example, the fill level of the treatment solution in the wet treatment tank can serve as a control variable for switching the pressure pump on and / or off to generate the directed flow of the treatment solution, thus preventing damage to the system.

[0045] Preferably, the free-flowing substance is selected from the group of organic and inorganic salts. In particular, organic sodium salts, such as sodium chloride and sodium sulfate, as well as inorganic salts, such as sodium carbonate, are suitable. In principle, any pumpable solids can be dosed according to the invention to produce liquid solutions or dispersions in water.

[0046] The problem is ultimately solved by a textile treatment process in which at least one free-flowing substance is added in a controlled manner to an aqueous treatment bath circulating in a cycle of a textile treatment plant for the treatment, in particular dyeing, of a textile substrate. The free-flowing substance to be added is preferably a substance from the selection mentioned above. The controlled addition is effected by means of a controlled conveying system connected to the storage container for transporting the free-flowing substance from the storage container to the feed opening of a mixing unit, and by means of a control unit connected to the controlled conveying system, which outputs a control signal to the controlled conveying system depending on a measured variable. The measured variable is preferably the quantity of the free-flowing substance contained in or drawn from the storage container.

[0047] Depending on the substance being dosed, the transport speed of the treatment solution in the textile treatment system's circuit is preferably adjusted by means of a programmable control system. For example, solid sodium carbonate can be dosed in this way over 20-30 minutes.

[0048] In particular, the textile treatment process according to the invention comprises the dyeing of cellulose with reactive dye using salt (sodium chloride or sodium sulfate) to improve dye extraction, as well as without the use of salt, as described above. Furthermore, the textile treatment process according to the invention preferably comprises a pretreatment and / or a posttreatment as described above.

[0049] Preferably, the method comprises the powdered dosing of solid sodium carbonate to the treatment bath, whereby the concentration of sodium ions (electrolyte) and the pH value are slowly and uniformly increased, preferably to a pH value of approximately 11.

[0050] Further advantageous embodiments and benefits of the invention are explained below with reference to the accompanying figures. These show: Fig. 1 a side view of an embodiment of the device according to the invention for dry dosing; Fig. 2 a bottom view of the embodiment; Fig. 3 a second perspective view of the embodiment, rotated relative to the first; Fig. 4 a third, further rotated perspective view of the embodiment; Fig. 5 a perspective and semi-transparent view of the storage container of the embodiment; Fig. 6 a perspective and semi-transparent view of the conveying system of the embodiment; Fig. 7 a perspective and semi-transparent view of the mixing unit of the embodiment and Fig. 8 a schematic representation of an embodiment of the device according to the invention for dry dosing.

[0051] In the Fig. Figures 1 to 4 each show the same embodiment of the inventive device 100 for dry dosing in its entirety. These figures are referred to collectively below.

[0052] The device 100 comprises a storage container 102 for the pourable substance in its upper section and an attached mixing unit 104 in its lower section. The mixing unit 104 has an inlet 106 and an outlet 108 for the aqueous treatment solution. The inlet 106 and the outlet 108 of the mixing unit 104 can be connected to a wet treatment tank of a textile treatment plant (not shown). The flow direction of the treatment solution is indicated by arrows 110 and 112.

[0053] The device 100 further comprises below the storage container 102 a controlled conveying system 114 connected to the storage container 102 for the controlled transport of the free-flowing substance from the storage container 102 to the mixing unit 104.

[0054] To illustrate the internal elements, the circumferential wall of the storage container 102 is shown in Fig. Figure 5 shows the transparent structure. The storage container 102 is essentially cylindrical, with a cylindrical circumferential wall 120, a flat bottom wall 122, and a partially openable lid 124. An outlet opening 126, covered by a grid, is provided in the bottom wall 122. A rotating agitator 128, which is rotatable about the cylinder axis, is located directly above the bottom wall 122 and is driven by a motor 130 located below the container. The agitator 128 keeps the contents, i.e., the dry substrate, moving within the storage container 102, thus preventing the formation of voids and ensuring a uniform fill level. This guarantees that the contents completely cover the bottom wall 122. The agitator 128 has two arcuate blades and rotates towards their concave front surface.This geometry further promotes radial transport of the material towards the inner apex of the arc, which is located radially at a distance from the axis of rotation such that it overlaps the outlet opening 126. The cover grid in the outlet opening 126 interacts with the agitator 128 by increasing the shear in the plane of the outlet opening 126, thus counteracting the formation of agglomerates and clumps. Through these measures, the agitator 128 ensures continuous transport even with materials that are not free-flowing. In this way, a continuous discharge of the material through the outlet opening 126 from the storage container 102 into the conveying system 114 below is guaranteed.

[0055] The storage container 102 is mounted on three stands 140. On each stand 140, as well as on the outside of the cylinder wall 120, there are opposing pairs of flanges 142 and 144. More precisely, the opposing pairs of flanges 142 and 144 are slightly offset from each other in the circumferential direction. A load cell 146 is located between each pair of flanges 142 and 144. The weight of the storage container 102 and its contents is thus transferred to the stands 140 via the three load cells 146. In this embodiment, the three load cells 146 together form the measuring unit in the form of a weighing unit. The weighing unit is thus configured to determine the mass of the powdered or granular substance contained in the storage container 102 and, indirectly, the mass of the powdered or granular substance removed from the storage container 102.

[0056] In Fig. Figure 6 shows the conveying system 114 in detail, with some parts shown semi-transparently to illustrate internal elements. The conveying system comprises a housing 150, which has a filling nozzle 152 on its upper side. This nozzle is connected to the outlet opening 126 of the storage container 102 by means of a flange 154. A screw conveyor 156 is located inside the housing 150, and its conveying direction is indicated by an arrow 158. The screw conveyor 156 is driven by a variable-speed drive 160, consisting of a drive motor 162 and a gearbox 164 for adjusting the motor speed. The drive 160 is connected to a control unit (not shown), which outputs a control signal to the variable-speed drive 160 depending on certain process parameters, i.e., control variables, in order to control the speed and thus the conveying flow.The controlled variable in this case is the specific mass of the free-flowing substance taken from the storage container 102. The screw conveyor 156 transports the free-flowing substance falling from the storage container 102 accordingly with a controlled flow rate in a horizontal direction 158 to the end of the housing 150, to which an enclosure 166 of a discharge chute is flanged. At the end of the housing 150 is an outlet opening 168, which communicates fluidically with the discharge chute. Optionally, one or more additional sieves can be provided in the outlet opening 168 to counteract any agglomeration or clumping of the free-flowing substance.Opposite the discharge opening 168 in the discharge chute is a closing element 172, movable by means of an actuator 170, which can be used to close the discharge opening 168 after the dosing process in order to protect the substance stored in the storage container 102 and the conveying system 114, in particular from penetrating moisture. After the substance exits the discharge opening 168, it falls through the discharge chute into the mixing unit 104 located below.

[0057] The mixing unit 104 is in Fig. Figure 7 is also shown partially semi-transparently to illustrate internal elements. The mixing unit 104 comprises a pre-dissolving container 180 with a cylindrical circumferential wall 182, a funnel-shaped bottom wall 184, and a lid 186. The lid 186 has a feed opening 188 into which the lower end of the housing 166 opens. The solid substance falls into the pre-dissolving container 180 through the feed opening 188 by gravity. One or more sieves may also be located in the feed opening 188 to counteract agglomeration or clumping of the solid substances that would be promoted by the conveying process.

[0058] In this example, the pre-dissolving tank 180 is equipped with three inlets 190 for the treatment solution. Each inlet 190 is connected to an annular channel 192 for the uniform distribution of the liquid flow to the inlets 190. The annular channel 192, in turn, is in fluidic communication with the inlet 106 via a connecting pipe 194. The flow can be controlled by a valve 196 installed in the connecting pipe 194. The three inlets 190 each open into the pre-dissolving tank 180 in such a way that the treatment solution introduced via them circulates within the pre-dissolving tank 180, in this case approximately tangentially. Depending on the geometry and arrangement of the pre-dissolving tank 180 and the inlets 190, a single inlet 190 may also be sufficient to generate circulation. However, two, four or more inlets 190 may also prove suitable.The inlet opening 188 is therefore arranged above a section of the treatment solution circulating in the pre-dissolving tank 180. The pre-dissolving tank 180 has a bottom outlet 198 at the base of the funnel-shaped bottom wall 184, through which the circulating, pre-dissolved treatment solution, i.e., the treatment solution with the not yet completely dissolved, homogeneously distributed solid substance, flows out in a turbulent, swirling manner.

[0059] Below the pre-dissolving tank 180, the mixing unit 104 has an injection unit 200. This is fluidically connected to the outlet 198 of the pre-dissolving tank 180. The injection unit 200 comprises a discharge volume 202 into which a pipe nozzle 203, connected to the outlet 198 of the pre-dissolving tank 180, opens. An injector nozzle 206, fluidically connected to the inlet 106 of the mixing unit 104 via a connecting pipe 204, is arranged in the discharge volume 202. This nozzle has an outlet opening at its narrowest point. The flow of the treatment solution can also be controlled here by a valve 208 installed in the connecting pipe 204. Furthermore, a pressure pump 210 is installed in the connecting pipe 204, as described in Fig. 8 schematically represented to provide a defined pressure to generate a directed flow of the treatment liquor within the receiving volume 202.

[0060] Downstream of the outlet opening is a diffuser 212 into which the stream flows. An annular gap is formed between the outlet opening of the nozzle 206 and the opening of the diffuser 212, in which the stream has a cross-section constricted to match the size of the outlet opening. Due to the constricted stream, a hydrostatic pressure reduced compared to the ambient pressure is generated according to the principle of a Venturi tube. This pressure draws in the mixture flowing from the pre-dissolving vessel 180, which is then carried along by the stream. Shear forces occur again during this process, further homogenizing the mixture.

[0061] A connecting pipe 214 is attached to the outlet side (downstream) of the diffuser 212 and is connected to the outlet 108 of the mixing unit 104. The treatment solution is returned to the textile treatment system's circuit after dosing via this route.

[0062] Furthermore, in this embodiment of the invention, the device 100 has a liquid container 220 for a liquid to be added to the dye bath. For this purpose, the liquid container 220 is connected to the pre-dissolving container 180 via a connecting line 222. Extending from the connecting line 222 is a flushing line 224. Furthermore, a first branch 226, a second branch 228, and a third branch 230 extend from the connecting line 222. The third branch 230 also serves as a flushing line. Both flushing lines 224 and 230 can be disconnected during operation of the system by means of a shut-off valve 232.

[0063] The liquid container 220 can be fluidically connected to the pre-dissolving container 180 via the first branch 226 and the second branch 228. Downstream of the branches, the first and second branches 226 and 228 each contain a liquid metering device in the form of a first metering valve 234 and a second metering valve 236, respectively. These serve to control the supply of liquid to the pre-dissolving container 180 at various speeds and in different quantities. Downstream of the liquid metering devices, the branches 226, 228, and 230 are rejoined in a feed pipe 240, which opens into the pre-dissolving container 180 from above through the cover 186.The connecting line 222 together with the two branches 226 and 228 and the feed pipe 240 thus form, in accordance with the claims, a supply line fluidically connecting the liquid container 220 with the pre-dissolving container 180, into which a liquid metering device is inserted.

[0064] Fig. Figure 8 shows a schematic representation of the device for dry dosing according to the invention. The preceding explanations also refer to this representation with reference to the same reference numerals. Reference symbol list 100 Dosing device 102 storage containers 104 mixing unit 106 Inflow 108 Procedure 110 Flow direction arrow, inlet side 112 Flow direction arrow, downstream side 114 Conveyor system 120 cylindrical circumferential walls 122 flat floor wall 124 lids 126 Outlet opening 128 Stirring element 130 drive motor 140 stands 142 Flange 144 Flange 146 Load cell 150 cases 152 Filler necks 154 Flange 156 auger 158 Direction of conveyance arrow 160 drive 162 Drive motor 164 gearbox 166 Enclosure 168 Exit opening 170 actuator 172 Locking element 180 pre-dissolving containers 182 cylindrical circumferential walls 184 funnel-shaped bottom wall 186 lids 188 Bedding opening 190 admission 192 Ring canal 194 Connecting pipe 196 valve 198 Expiry 200 injection units 202 purchase volume 204 Connecting pipe 206 Injector nozzle 208 Valve 210 pressure pump 212 Diffuser 214 Connecting pipe 220 liquid containers 222 Connecting line 224 Flushing line 226 first junction 228 second junction 230 third turn 232 Shut-off valve 234 first metering valve 236 second metering valve 240 feed pipe

Claims

[1] Textile treatment plant for the treatment, in particular dyeing, of textile substrates, comprising a device (100) for dosing a bulk substance to an aqueous treatment bath for the treatment, in particular dyeing, of a textile substrate and a wet treatment tank for receiving and treating the textile substrate, wherein the device comprises: a storage container (102) for the loose substance, a mixing unit (104) which has an inlet (106) and an outlet (108) for the aqueous treatment liquor and a sprinkling opening (188) for the pourable substance, a controlled conveying system (114) connected to the storage container (102) for transporting the pourable substance from the storage container (102) to the spreading opening (188), and a control unit connected to the regulated conveying system (114), which is configured to output a control signal to the regulated conveying system (114), and wherein the wet treatment tank is connected to the inlet (106) and outlet (108) of the mixing unit (104) by means of a pipe connection in order to transfer the aqueous treatment liquor into the wet treatment tank. [2] Textile treatment plant according to claim 1, characterized by , that the regulated conveying system (114) includes a screw conveyor (156) which is designed to transport the pourable substance from the storage container (102) to the bedding opening (188). [3] Textile treatment plant according to one of the preceding claims, characterized by , that the regulated conveying system (114) has a controllable drive (160) connected to the control unit. [4] Textile treatment plant according to one of the preceding claims, characterized bythat the storage container (102) or the controlled conveying system (114) includes a measuring unit which is designed to determine a quantity of the bulk substance contained in the storage container (102) or taken from the storage container (102). [5] Textile treatment plant according to claim 4, characterized by , that the measuring unit is a weighing unit which is set up to determine a mass of the bulk substance contained in the storage container (102). [6] Textile treatment plant according to one of claims 4 or 5, characterized by , that the measuring unit is connected to the control unit and is set up to output a measured quantity to the control unit and that the control unit is set up to vary the control signal to the controlled conveying system (114) depending on the measured quantity. [7] Textile treatment plant according to one of the preceding claims, characterized by, that the storage container (102) includes a stirring element (128) which is designed to keep the free-flowing substance contained in the storage container (102) in motion. [8] Textile treatment plant according to one of the preceding claims, characterized by , that the mixing unit (104) comprises a pre-dissolving tank (180) with an inlet (190) for the aqueous treatment liquor, wherein the inlet (190) is fluidically connectable to the inlet (106) and opens into the pre-dissolving tank (180) in such a way that the aqueous treatment liquor introduced into the pre-dissolving tank (180) via the inlet (190) circulates in the pre-dissolving tank (180). [9] Textile treatment plant according to claim 8, characterized by , that the inlet opening (188) is arranged above a section of the aqueous treatment liquor circulating in the pre-dissolving container (180). [10] Textile treatment plant according to claim 8 or 9, characterized by, that the pre-dissolving container (180) has a bottom outlet (198) and that the mixing unit (104) below the pre-dissolving container (180) has an injection unit (200) which is fluidically connected to the bottom outlet (198) of the pre-dissolving container (180). [11] Textile treatment plant according to claim 10, characterized by , that the injection unit (200) has a take-up volume (202) which is fluidically connected to the bottom outlet (198) of the pre-dissolving tank (180) and that an injector nozzle (206) which can be fluidically connected to the inlet (106) of the mixing unit (104) is arranged in the take-up volume (202) and which is configured to generate a directed flow of the aqueous treatment liquor within the take-up volume (202). [12] Textile treatment plant according to claim 11, characterized by , that the output volume (202) is connected to the outlet (108) of the mixing unit (104). [13] Textile treatment plant according to one of the preceding claims, characterized by , that the device (100) has a liquid container (220) for a liquid to be added to the dye bath and a supply line fluidically connecting the liquid container (220) to the mixing unit (104), into which a liquid metering device is inserted. [14] Textile treatment plant according to one of the preceding claims, characterized by that the control unit is part of a programmable control system for the textile treatment plant. [15] Textile treatment process in which at least one free-flowing substance is added in a controlled manner to an aqueous treatment liquor circulating in a circuit of the textile treatment plant according to one of claims 1 to 14 for the treatment, in particular dyeing, of a textile substrate, wherein the controlled addition in the device (100) for dosing the free-flowing substance is carried out by means of the controlled conveying system (114) connected to the storage container (102) for transporting the free-flowing substance from the storage container (102) to the inlet opening (188) of the mixing unit (104) and by means of the control unit connected to the controlled conveying system (114), which outputs the control signal to the controlled conveying system (114) depending on a measured variable.

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