Method and system for dewatering batches of washed laundry

Abstract

The present invention relates to a method for dewatering batches of washed laundry. The present invention also relates to a method for washing batches of laundry, comprising the steps of washing at least one batch of laundry, by using at least one laundry washing device, such as a batch washer or tunnel washer, followed by at least partially dewatering said batch of laundry washed by applying the dewatering method according to the invention. The invention further relates to a system for dewatering batches of washed laundry, preferably by making use of a method according to the invention.

Description

[0001] The present invention relates to a method for dewatering batches of washed laundry. The present invention also relates to a method for washing batches of laundry, comprising the steps of washing at least one batch of laundry, by using at least one laundry washing device, such as a batch washer or tunnel washer, followed by at least partially dewatering said batch of laundry washed by applying the dewatering method according to the invention. The invention further relates to a system for dewatering batches of washed laundry, preferably by making use of a method according to the invention. The invention moreover relates to the use or intended use of a microwave radiation device to preheat batches of laundry to be dewatered in a method according to the invention.

[0002] In industrial laundry facilities, large quantities of laundry are processed daily. After washing, the laundry retains a significant amount of water that must be removed before the laundry can be considered fully processed. Conventional dewatering methods often rely on mechanical pressing followed by tumble drying or other heat-based drying techniques. The known methods are energy-consuming and often time-consuming before a batch of laundry has reached a desired moisture level.

[0003] It is an object of the invention to an improved, and more in particular a relatively energy-efficient, method and system for dewatering batches of washed laundry.

[0004] To this end, the invention proposes a method for dewatering batches of washed laundry, comprising the steps of: A) inspecting at least one batch of washed laundry to be dewatered by means of at least one inspection device to determine the presence or absence of one or more metal items in said batch of washed laundry to be dewatered, B) only in case during step A) no metal item is detected in said batch of washed laundry, subjecting said batch of washed laundry to microwaves, by using at least one microwave radiation device, to preheat said batch of washed laundry, and C) following step A) and conditionally following step B), subjecting said batch of washed laundry to at least one drying step, by using at least one laundry drying device, to heat and at least partially dewater said batch of washed laundry.

[0005] Hence, the method according to the invention comprises three main steps: inspection for metal items, conditional microwave treatment, and (conventional) drying. By conditionally applying the preconditioning step of the microwave treatment, the washed laundry will be thoroughly preheated (and partially dried) before the laundry is led into or through a conventional dryer to further dry (dewater) the laundry.

[0006] The application of a microwave based preheating (preconditioning) step (step B)) has a plurality of advantages. Microwaves generate heat by directly exciting water molecules inside the fabric, allowing for faster and more even drying. This method reduces drying time significantly compared to conventional drying methods like hot air or tumble drying. Since microwaves heat the water molecules directly, the drying process is more uniform across the fabric, which can prevent hotspots or uneven drying that might occur in other methods. Microwave drying targets the moisture within the fabric rather than heating the surrounding air, which reduces overall energy consumption. Because the drying process is faster, the energy required per batch of laundry is lower, making the process more energy-efficient compared to traditional drying methods. Microwave drying typically operates at lower external temperatures than conventional tumble dryers, which rely on hot air. This reduces the risk of fabric damage, shrinkage, or colour fading caused by prolonged exposure to high heat. Furthermore, microwaves have the potential to kill or inactivate microorganisms (such as bacteria and fungi) during the drying process. This can help improve hygiene standards, especially for textiles used in healthcare or food service industries. The energy efficiency of the application of one or more microwave radiation devices translates into a lower carbon footprint, especially for industrial laundry facilities that handle large volumes of laundry daily.

[0007] A metal presence inspection step (step A)) is carried out to determine the presence or absence of metal, in particular metal items, such as for example metal buttons, metal clips, metal eyes, metal rivets, metal fasteners, metal hooks and eyes, metal chains, metal tags, metal logos, metal zippers, metal tools, and other metal particles, in each batch of laundry to be dewatered. In case metal is detected, the microwave treatment (step B)) will be skipped to prevent unsafe situations as well as to prevent damaging of the laundry. Metal pieces, such as the examples listed above, can cause electrical arcing when exposed to microwaves as microwaves create electric currents in the metal, which may cause sparking. These sparks can lead to damage inside the microwave and may even cause fire. Moreover, these sparks can lead to visible burn marks or holes in the laundry leading to permanent damage. Furthermore, the arcing caused by metal can damage the microwave radiation device potentially leading to malfunction or permanent failure of the appliance. In order to prevent avoid risks in this respect, the microwave treatment is performed only to a specific batch of washed laundry in case it is determined in a preceding inspection step (step A) that said batch of laundry is free of metal, in particular free of metal items.

[0008] The metal presence inspection step (step A) may based upon various technologies, such as conventional metal detection techniques to detect the presence of metallic objects through electromagnetic fields. Metal detectors work by generating a magnetic field and measuring disturbances caused by metal objects within that field. Examples of these conventional metal detector technologies are (i) Magnetic Particle Inspection (MPI), which relies on magnetism to detect ferromagnetic metals, and (ii) Eddy current testing, which uses electromagnetic fields to detect conductive metals (both ferrous and non-ferrous). This technique is often classified under electromagnetic metal detection because it detects the electrical conductivity of metals.

[0009] Additionally or alternatively to one or more of the metal detection technologies addressed above, the inspection step (step A)) may based upon X-ray detection. X-ray detection refers to the use of X-ray technology to visualize the internal structure of each batch of laundry. X-rays pass through materials, and different substances, such as metal items, absorb or scatter X-rays to varying degrees, creating an image or indication of what is inside said batch of laundry. An example of a suitable X-ray detection method step (step A)) is X-ray Fluorescence (XRF). XRF is a nondestructive technique where the laundry is bombarded with X-rays, causing metal particles to emit secondary X-rays. These emissions can be used to identify the presence of metals, including non-magnetic or non-ferrous metals. Another example of a suitable X-ray detection method (step A)) is X-ray Imaging (Radiography). X-ray imaging involves passing X-rays through the laundry and detecting the internal structure. Metal particles, being denser than textile fibers of the laundry, appear clearly in X-ray images.

[0010] Combinations of two or more metal presence detection technologies, in particular as described above, may be used during step A).

[0011] The method (and system) according to the invention are primarily designed for industrial use rather than for domestic use, although this latter option is not excluded. More in particular, the method (and system) according to the invention are primarily designed to be integrated with and / or connected to an industrial laundry washing facility wherein large volumes of laundry to be cleaned for various industries and organizations are handles. The types of laundry washed in these facilities can vary depending on the sector they serve, but common types include (i) healthcare textiles, such as hospital linen (bed sheets, pillowcases, blankets, and towels used in hospitals), patient gowns (clothing worn by patients), surgical gowns and drapes (used during surgeries and medical procedures), medical staff uniforms (scrubs, lab coats, and other workwear for healthcare workers) and reusable cloth-based incontinence pads, and (ii) hospitality and accommodation textiles, such as hotel linens, towels, tablecloths, napkins, bathrobes and spa textiles. The handling, in particular cleaning, of other textiles is also imaginable.

[0012] As indicated above, the laundry is preheated during the microwave treatment, which will typically lead to partial dewatering. This reduces the workload on the subsequent drying step, decreasing overall energy consumption. The degree of partial dewatering during step B) may be adjustable, for example based on laundry type, laundry weight, and / or initial moisture content. During step B) a temperature, preferably a surface temperature, of the batch of laundry is preferably measured, more preferably by using at least one infrared sensor. This temperature measurement may be used to determine the length of the preheating step B), which may, for example, continue until a predefined temperature, preferably surface temperature, has been reached. Additionally or alternatively, step B) may be performed during a predetermined amount of time, and / or a predetermined minimum amount of time and / or a predetermined maximum amount of time.

[0013] At least one microwave radiation device used during step B) preferably comprises at least one shielded treatment chamber. A shielded chamber in a microwave treatment device for preheating (and pre-drying) washed laundry offers several advantages, particularly for improving efficiency, safety, and drying quality. For example. the shielded chamber ensures that microwaves do not escape into the surrounding environment, protecting workers from exposure to microwave radiation. This containment is essential for both safety and regulatory compliance. Moreover, the shielded chamber helps maintain a controlled environment, ensuring consistent temperature conditions, which could be critical for sensitive fabrics and garments.

[0014] Preferably, during step B) the batch of laundry is preheated with microwaves having a wavelength of between 5 and 35 cm, preferably between 12 and 13 cm. More preferably, the preferred wavelength of microwaves used to preheat washed, wet laundry typically falls within the microwave frequency range of 2.45 GHz, which corresponds to a wavelength of approximately 12.24 cm. Microwaves at 2.45 GHz are well-suited for heating water molecules, which is essential for pre-drying wet laundry. Water molecules absorb microwave energy efficiently at this frequency, causing them to vibrate and heat up, which in turn evaporates the moisture from the fabric. The 2.45 GHz frequency is also an industrial, scientific, and medical (ISM) band that is globally regulated for non-communication purposes, ensuring safe and standardized use in commercial and industrial microwave drying systems. Despite of the preference of using the2.45 GHz frequency, other microwave frequencies may, additionally or alternatively, also be used during step B).

[0015] During step B) the batch of laundry is preferably moved, in particular rotated, preferably about a vertical axis, at least for a period of time during step B). Microwaves could penetrate materials unevenly, particularly in dense or stacked fabrics. By rotating or otherwise moving the laundry, all areas of the fabric are exposed to the microwaves more consistently, reducing the risk of uneven drying or "hot spots" where certain areas dry faster than others. Furthermore, rotation or other movements of the laundry helps distribute the energy more evenly, protecting delicate fabrics from excessive heat. It is also imaginable that the microwave radiation sources moves with respect to the laundry, wherein the laundry itself is kept stationary during the microwave treatment. Moving both (at least a part of) the microwave radiation source and the laundry during step B), wherein (at least a part of) the microwave radiation source and the laundry are moved with respect to each other during step B).

[0016] During step B) humid air released from the batch of laundry is preferably discharged from the microwave radiation device. This discharge may a be a passive discharge by simply applying a discharge opening in the microwave radiation device and / or may be an active discharge to actively discharge the humid air from the microwave radiation device, for example by using a fan or other air suction device.

[0017] Preferably, said at least one inspection device, said at least one microwave radiation device, and said at least one laundry drying device are positioned in series with each other allowing successive execution of step A), conditional step B), and step C), preferably in a continuous or semi-continuous manner. This arrangement allows for efficient, continuous processing of laundry batches. It is conceivable that multiple parallel processing lines (systems to carry out at the method according to the invention, including said at least one inspection device and / or said at least one microwave radiation device, and / or said at least one laundry drying device) may be used to increase overall throughput. A combination between components arranged in parallel and other components of the system arranged in series is also imaginable. Different systems of which two or more equivalent components are arranged in parallel may used at least one shared component, such as a shared inspection device to perform step A) of the method according to the invention. Since at least one shared component is used the different system may also be considered as a single system, in particular a single branched system.

[0018] Preferably, in case during step A) at least one metal item is detected in said batch of washed laundry, the batch of washed laundry is led through or along said at least microwave radiation device in non-operational state to the at least one laundry drying device prior to performing step C). As indicated above, this approach prevents unsafe or undesired situations, while a relatively simple, typically linear, arrangement can be maintained.

[0019] Alternative embodiment: A separate handling system for metal-containing batches may be implemented for more specialized treatment.

[0020] Conditional step B) is preferably directly performed after completion of step A) (in case no presence of one or more metal items is detected during step A). This direct continuation with step B) after completion of step A) prevents that the inspected batch of laundry has to be temporarily stored which could lead to the risk that one or more metal items are added to the inspected batch of laundry, for example due to a human mistake, prior to performing step B), which could lead to dangerous situations.

[0021] From an energetic point of view, step C) is preferably directly performed after conditional completion of step B) and / or after completion of step A). The immediate progression between steps maintains thermal efficiency and reduces overall processing time. In this case, the batch of preheated, washed laundry, still having an elevated temperature, is fed into the at least one drying device. This does not exclude the possibility that brief holding periods between steps may be introduced to allow for additional treatments or inspections.

[0022] Said batch of laundry may be conveyed from the at least one inspection up to the laundry drying device by using at least one conveyor. A conveyor use allows for automated, continuous processing with minimal manual intervention. Alternative or additionally, robotic arms or automated guided vehicles may be used for more flexible laundry transport, particularly in facilities with complex layouts.

[0023] The method may comprise step D), comprising the step of compressing at least one, preferably each, batch of laundry to be dewatered during conditional step B) and step C), by using at least one dewatering press, wherein during step D) at least one compressed laundry in is formed. Apart from the pre-dewatering during step D) which already reduces the moisture content of the laundry significantly, which requires less processing time for steps B) and C). Moreover, compression can enhance microwave penetration which is in favour of the efficiency of step B). Optionally, during step B) the compression level may be adjusted, preferably based on laundry type, and / or initial moisture content, and / or desired final moisture content.

[0024] Step D) is preferably performed prior to step A). A pre-inspection compression can standardize batch size for more consistent processing and potentially improve metal detection accuracy. Optionally, said compression may be performed in multiple stages, with initial compression before inspection and at least one additional compression before or during microwave treatment.

[0025] Preferably, each laundry cake has a dry weight of at least about 25 kg, preferably at least 30 kg, more preferably at least 35 kg. Larger batch sizes can improve overall process efficiency and throughput. The system may accommodate variable batch sizes, with processing parameters automatically adjusted based on the weight and dimensions of each batch. Hence, the batch size and / or weight may differ per batch.

[0026] As indicated above, the at least one inspection device used during step A) preferably comprises at least one metal detector configured to determine the presence of absence of one or more metal items, such as for example metal buttons, metal clips, metal eyes, metal rivets, metal fasteners, metal hooks and eyes, metal chains, metal tags, metal logos, metal zippers, metal tools, and other metal particles, in each batch of laundry to be dewatered. Preferably, at least one metal detector comprises at least one x-ray scanner to determine the presence of absence of one or more metal items in each batch of laundry, wherein a pixel resolution of said x-ray scanner is preferably at least 100 micrometre. This relatively high resolution allows detection of even small metal items, enhancing safety and potentially reducing false positives. During step A) an x-ray energy level of said x-ray scanner of at least 80 k eV is preferably used. Higher energy levels can improve penetration and detection accuracy, particularly for dense laundry loads. Pulsed x-ray technology may be used to provide high energy levels with reduced overall radiation exposure. It is imaginable that during step A) an x-ray energy level of said x-ray scanner is adjustable, wherein the x-ray energy level is preferably adapted to the weight and / or dimensions of the batch of laundry. Adjustable energy levels allow for optimized scanning across different batch types and sizes, improving detection accuracy while minimizing unnecessary radiation exposure. Optionally, multi-view x-ray imaging may be implemented, using multiple x-ray sources and detectors to provide improved detection from multiple angles.

[0027] During step A) each batch of laundry is preferably moved through the inspection device, by using at least one conveyor. Continuous movement through the inspection device allows for efficient, high-throughput processing. A stop-and-go conveyor system may be implemented, pausing briefly during inspection for more detailed analysis of potentially problematic areas.

[0028] In a preferred embodiment, during step B) a temperature, preferably a surface temperature, of the batch of laundry is measured, preferably by using at least one infrared sensor, wherein the preheating continues until a predefined temperature, preferably surface temperature, has been reached. Temperature monitoring ensures controlled preheating, preventing overheating while ensuring sufficient energy input. Optionally, multiple temperature sensors may be used to create a thermal profile of the laundry batch, allowing for more precise and uniform heating.

[0029] During drying step C) a temperature, preferably a surface temperature, of the batch of laundry is preferably measured, more preferably by using at least one infrared sensor, wherein the preheating continues until a predefined temperature, preferably surface temperature, has been reached. Temperature monitoring during drying ensures controlled processing and prevents over-drying or heat damage. One or more machine learning algorithms may be employed to predict optimal drying endpoints based on temperature trends and laundry type.

[0030] During drying step C) the humidity of the batch of laundry may be measured, more preferably by using at least one humidity sensor. It is imaginable that the drying step continues until a predefined laundry humidity has been reached. Direct humidity measurement allows for precise control of the final moisture content, ensuring consistent results. Over-drying can cause wear and tear on fabrics, leading to shrinkage, fading, or fiber damage. A humidity sensor may help maintain the quality of textiles by ensuring they are dried just enough. Optionally, at least one non-contact moisture sensing technology, such as near-infrared spectroscopy, may be used for real-time, non-invasive moisture monitoring.

[0031] During step C) each batch of laundry is preferably at least partially dewatered by exposing said batch of laundry to air having a temperature of between 40 and 100 degrees Celsius, between 40 and 90 degrees Celsius, wherein the air temperature is preferably adjusted to the batch of laundry to be dewatered. This temperature range allows for effective drying while minimizing potential heat damage to fabrics. A multi-stage drying process may be implemented, using different air temperatures at different stages to optimize drying efficiency and fabric care. In case step B) is performed to preheat the batch of textile, the air temperature used during drying step C) can be lower to achieve the same drying results, which is saves energy. In case step B) is not performed, the air temperature used and / or drying time during drying step C) can be set to a higher value to achieve sufficient drying. The air temperature difference between the (maximum) temperatures used in these two scenarios (with or without applying step B)) may be situated in between 10 and 50 degrees Celsius, preferably in between 20 and 40 degrees Celsius. Typically a minimum drying temperature of 30, preferably 40, degrees Celsius is used during step C). A control unit used to control steps B) and C), preferably steps A), B), and C), may control the air temperature, in particular the maximum air temperature, to be used during step C), dependent on whether or not step B) is applied.

[0032] Preferably, step C) may be performed during a predetermined amount of time. Time-based control provides consistent processing and simplifies scheduling in industrial settings. Dynamic time adjustment may be implemented based on real-time moisture measurements and drying rate calculations.

[0033] During step C) the batch of laundry is preferably moved, more preferably tumbled. Movement during drying promotes more uniform results and can reduce overall drying time. Reversing tumble direction or variable speed tumbling may be employed to optimize drying uniformity and efficiency.

[0034] The invention also relates to a method for washing batches of laundry, comprising the steps of: E) washing at least one batch of laundry, by using at least one laundry washing device, such as a batch washer or tunnel washer, followed by at least partially dewatering said batch of laundry washed according to step E) by applying the method according to any of the preceding claims.

[0035] This integrated approach ensures a seamless transition from washing to dewatering, optimizing overall laundry processing efficiency. The washing step may incorporate one or more pre-treatment zones for specialized cleaning or stain removal prior to the main wash cycle. Optionally, washing step E) comprises a plurality of sub steps, preferably including the two or more of the following sub steps: E1) prewashing, E2) washing, E3) rinsing, and E4) neutralizing the batch of laundry. These multiple sub-steps allow for customized washing processes tailored to different laundry types and soil levels. Adaptive washing programs may be implemented, adjusting sub-step parameters based on real-time monitoring of water quality and soil removal.

[0036] In a preferred embodiment, the method comprises step F) comprising the step of weighing each one batch of laundry prior to washing said batch of laundry according to step E). Pre-wash weighing enables precise dosing of detergents and water, improving washing efficiency and resource utilization. One or more in-line, continuous weighing systems may be used to monitor weight changes throughout the washing process, allowing for dynamic adjustments of parameters, such as dosing related parameters, for example relating to the amount of detergent to be dosed and / or the timing of detergent dosing.

[0037] Preferably, the method comprises step G) comprising the step of sorting laundry prior to performing step F). Pre-sorting ensures optimal treatment for different laundry types and can improve overall processing efficiency. Automated sorting systems using machine vision and / or AI may be employed to classify and sort laundry items based on fabric type, colour, and soil level.

[0038] In a preferred embodiment, the method comprises to H) comprising the step of assigning a unique batch number to each batch of laundry, wherein said batch number is correlated to one or more properties of the particular batch of laundry, such as a the weight of said batch of laundry, and wherein step H) is performed prior to A, preferably prior to step E). Batch tracking improves process control, traceability, and allows for customized treatment based on batch properties. The uniqueness of the batch number may e.g. be a local uniqueness to allow mutual distinction of different batches over time, and / or may e.g. be a global uniqueness which may, for example, be characterized by a web address (Uniform Resource Locator (URL) and / or Uniform Resource Identified (URI)).

[0039] Preferably, at least one control unit is provided which controls, based upon the unique batch number, the at least one inspection device during step A), and / or the at least one microwave radiation device during step B) in case no metal item is detected within said batch during step A), and / or the laundry drying device during step C). This allows centralized control based on batch information which enables precise, customized processing for each laundry batch.

[0040] The invention additionally relates to a system for dewatering batches of washed laundry, preferably by making use of a method according to the invention, comprising: at least one inspection device to determine the presence or absence of metal items in said batch of washed laundry to be dewatered, at least one microwave radiation device configured to subject said batch of washed laundry to microwaves, by to preheat said batch of washed laundry, at least one laundry drying device configured to heat and at least partially dewater said batch of washed laundry, and at least one control unit configured to activate said at least one microwave radiation device only in case said at least one inspection device determines for a particular batch of washed laundry that said batch of washed laundry is free or any metal item.

[0041] As indicated above already, this integrated system ensures safe and efficient dewatering of laundry batches while preventing potential hazards associated with metal items. The system may incorporate parallel processing lines (defined by components arranged in series and / or in parallel) with redundant components to increase throughput and provide backup in case of equipment failure.

[0042] The at least one microwave radiation device is preferably configured to partially dewater the batch of washed laundry by preheating said batch of washed laundry. Partial dewatering during preheating reduces the workload on subsequent drying steps, potentially decreasing overall energy consumption and processing time.

[0043] The microwave radiation device may be configured to adjust power settings and / or the microwaves wavelength to adjust the degree of partial dewatering based on laundry type and initial moisture content.

[0044] Said at least one inspection device, said at least one microwave radiation device, and said at least one laundry drying device are preferably positioned in series with each other allowing continuous or semi-continuous dewatering process of washed laundry. This arrangement enables efficient, streamlined processing of laundry batches with minimal transfer time between steps. The system may include one or more buffer zones or accumulation conveyors between devices to accommodate variations in processing times and maintain continuous flow.

[0045] The system preferably further comprises at least one conveyor configured to convey said batch of laundry from the at least one inspection device up to the laundry drying device, wherein said conveyor is preferably controlled by said control unit. A controlled conveyor system ensures smooth and coordinated movement of laundry batches through the entire process. Multiple specialized conveyors may be used for different stages, such as high-speed conveyors for inspection and slower, vibrating conveyors for even distribution in the microwave device.

[0046] In a preferred embodiment, the system comprises at least one conveyor for transporting batches of washed laundry, wherein said conveyor is guided through or along said at least one microwave radiation device, wherein the control unit is configured to control the conveyor to guide batches of laundry successively through or along said at least one microwave radiation device, such that, dependent on the detected presence or absence of one or more metal items by the at least one inspection device for a particular batch of laundry, the at least one microwave radiation device is selectively switched off or on, respectively, for said particular batch of laundry. This configuration allows for continuous processing while ensuring safety by selectively activating the microwave device based on inspection results. A bypass conveyor system may be implemented to route metal-containing batches around the microwave device without interrupting the main process flow.

[0047] Preferably, the system comprises at least one dewatering press configured to compress at least one, preferably each, batch of laundry to be dewatered during operation of the at least one microwave radiation device and the at least one laundry drying device, wherein the at least one dewatering press is configured to form at least one compressed laundry cake. As indicated above, compression enhances microwave penetration and drying efficiency, potentially reducing overall processing time and energy consumption. The dewatering press may incorporate adjustable pressure settings to optimize compression based on laundry type and moisture content.

[0048] At least one inspection device preferably comprises at least one metal detector configured to determine the presence or absence of one or more metal items in each batch of laundry to be dewatered. Metal detectors, including x-ray scanners, provide reliable identification of potentially hazardous items, improving safety and protecting equipment. The at least one metal detector preferably comprises at least one x-ray scanner to determine the presence or absence of one or more metal items in each batch of laundry, wherein a pixel resolution of said x-ray scanner is preferably at least 100 micrometres. High-resolution X-ray scanning enables detection of even small metal items, enhancing safety and potentially reducing false positives. The X-ray scanner may utilize dual-energy technology to differentiate between different types of materials, improving detection accuracy and reducing false alarms. The x-ray scanner is preferably configured to operate at an x-ray energy level of at least 80 k eV. Higher energy levels improve penetration and detection accuracy, particularly for dense laundry loads or larger batches. The system, in particular the inspection device, may incorporate multiple X-ray sources with different energy levels to optimize detection across various laundry types and densities. Preferably, the x-ray scanner is configured with an adjustable x-ray energy level, wherein the x-ray energy level may be adapted to the weight and / or dimensions of the batch of laundry. Adjustable energy levels allow for optimized scanning across different batch types and sizes, improving detection accuracy while minimizing unnecessary radiation exposure. The system may employ real-time adaptive energy adjustment based on initial low-dose scans, automatically optimizing energy levels for each batch.

[0049] Preferably, at least one microwave radiation device comprises at least one temperature sensor, preferably an infrared sensor, configured to measure a temperature, preferably a surface temperature, of the batch of laundry during operation of the at least one microwave radiation device, wherein the system, in particular the control unit and / or the microwave radiation device, is configured to continue preheating until a predefined temperature, preferably surface temperature, has been reached. Temperature monitoring ensures controlled preheating, preventing overheating while ensuring sufficient energy input for efficient dewatering. Multiple temperature sensors may be used to create a thermal profile of the laundry batch, allowing for more precise and uniform heating control.

[0050] Preferably, the at least one microwave radiation device is configured to discharge humid air released from the batch of laundry, and / or wherein the laundry drying device is configured to discharge humid air released from the batch of laundry from the laundry drying device. Removing humid air improves drying efficiency and prevents moisture reabsorption, potentially reducing overall processing time. Optionally, the system may incorporate a heat recovery unit to capture and reuse the energy from the discharged humid air, improving overall energy efficiency.

[0051] The at least one laundry drying device preferably comprises at least one temperature sensor, preferably an infrared sensor, configured to measure a temperature, preferably a surface temperature, of the batch of laundry during operation of the at least one laundry drying device, wherein the system, in particular the control unit and / or the laundry drying device, is configured to continue drying until a predefined temperature, preferably surface temperature, has been reached. Temperature monitoring during drying ensures controlled processing and prevents over-drying or heat damage to laundry items. The system may employ machine learning algorithms to predict optimal drying endpoints based on temperature trends, laundry type, and historical data.

[0052] The at least one laundry drying device preferably comprises at least one humidity sensor configured to measure the humidity of the batch of laundry during operation of the at least one laundry drying device. The system, in particular the control unit and / or the laundry drying device, may be configured to continue the drying step until a predefined laundry humidity has been reached. Direct humidity measurement allows for precise control of the final moisture content, ensuring consistent results across different laundry types and initial moisture levels. The system may incorporate one or more non-contact moisture sensing technologies, such as near-infrared spectroscopy, for real-time, non-invasive moisture monitoring throughout the drying process.

[0053] The at least one laundry drying device is preferably configured to expose each batch of laundry to air having a temperature of between 40 and 100 degrees Celsius, between 40 and 90 degrees Celsius, wherein the air temperature may be adjusted to the batch of laundry to be dewatered. This temperature range allows for effective drying while minimizing potential heat damage to fabrics, with adjustability to accommodate different laundry types. The system may implement a multi-stage drying process with different air temperatures at each stage, optimizing both drying efficiency and fabric care.

[0054] At least one laundry drying device is preferably configured to move, preferably tumble, the batch of laundry during operation of said at least one laundry drying device. Movement during drying promotes more uniform results, reduces drying time, and can help prevent wrinkles in the laundry. The drying device may be configured to employ one or more variable tumbling patterns, such as reversing directions or intermittent pauses, to optimize drying efficiency and fabric care for different laundry types.

[0055] The system preferably comprises at least one laundry washing device, wherein said at least one laundry washing device is preferably a batch washer or a tunnel washer or a continuous washer. Integrating washing and dewatering processes in a single system improves overall efficiency and reduces handling requirements. Preferably, the at least one laundry washing device is configured to perform a plurality of sub steps, preferably including two or more of the following sub steps: prewashing, washing, rinsing, and neutralizing the batch of laundry. Multiple sub-steps allow for customized washing processes tailored to different laundry types and soil levels, improving cleaning effectiveness. The laundry washing device(s) may be programmed to employ one or more adaptive washing programs that adjust sub-step parameters based on real-time monitoring of water quality, soil removal, and pH levels.

[0056] Preferably, the system comprises at least one weighing device configured to weigh each batch of laundry prior to washing said batch of laundry. Pre-wash weighing enables precise dosing of detergents and water, improving washing efficiency and resource utilization. The weighing device(s) may be configured to continuous weigh the batches of laundry throughout the process and / or a during multiple steps of said process, allowing for dynamic adjustments to washing, microwave treatment, and drying parameters based on real-time weight changes. Preferably, the system comprises at least one sorting device configured to sort laundry prior to weighing by the at least one weighing device. Pre-sorting ensures optimal treatment for different laundry types and can improve overall processing efficiency by grouping similar items.

[0057] The system, in particular the control unit, is preferably configured to assign a unique batch number to each batch of laundry, wherein said batch number is correlated to one or more properties of the particular batch of laundry, such as the weight of said batch of laundry, and wherein said unique batch number and said correlated one or more properties are stored by the control unit and / or onto a digital storage memory of the system. Batch tracking improves process control, traceability, and allows for customized treatment based on batch properties throughout the entire washing and dewatering process. Optionally, the system may utilize blockchain technology to create an immutable record of each batch's processing history, enhancing traceability and quality assurance. Preferably, the at least one control unit is configured to control, based upon the unique batch number, the at least one inspection device, and / or the at least one microwave radiation device in case no metal item is detected within said batch by the at least one inspection device, and / or the laundry drying device. A centralized control based on batch information enables precise, customized processing for each laundry batch, optimizing efficiency and quality.

[0058] The invention moreover relates to the use or intended use or method for using of a microwave radiation device to preheat batches of laundry to be dewatered in a method according to the invention and / or system according to the invention. As indicated above extensively, microwave preheating can significantly reduce overall dewatering time and energy consumption compared to traditional methods.

[0059] The invention will be elucidated in the description of the accompanying non-limitative figures, in which: figure 1 shows a flowchart for a method of dewatering batches of washed laundry according to an embodiment of the invention, figure 2 shows a flowchart for a method of dewatering batches of washed laundry according to an embodiment of the invention, figure 3 shows a flowchart for washing laundry, according to an embodiment of the invention, figure 4 shows a flowchart for washing a batch of laundry, according to an embodiment of the invention, figure 5 shows a system for dewatering batches of washed laundry, according to an embodiment of the invention, and figure 6 shows a system for washing batches of laundry, according to an embodiment of the invention.

[0060] Figure 1 illustrates a flowchart for a method of dewatering batches of washed laundry. The method comprises three steps: A, B, and C.

[0061] Step A involves inspecting at least one batch of washed laundry to be dewatered using at least one inspection device. The purpose of this inspection is to determine the presence or absence of one or more metal items in the batch of washed laundry.

[0062] Step B is a conditional step that follows Step A. This step is only performed if no metal item is detected in the batch of washed laundry during Step A. In Step B, the batch of washed laundry is subjected to microwaves using at least one microwave radiation device. The purpose of this step is to preheat the batch of washed laundry.

[0063] Step C follows Step A and conditionally follows Step B. In this step, the batch of washed laundry is subjected to at least one drying step using at least one laundry drying device. The purpose of this step is to heat and at least partially dewater the batch of washed laundry.

[0064] The flowchart demonstrates a sequential process with a conditional step, highlighting the importance of the metal detection step in determining whether microwave preheating is applied. This method may combine inspection, conditional microwave treatment, and drying to process batches of washed laundry efficiently.

[0065] Figure 2 illustrates a flowchart for a method of dewatering batches of laundry. This method comprises four steps: D, A', B', and C'.

[0066] Step D involves compressing the batch of laundry to be dewatered using at least one dewatering press, forming a compressed laundry cake. This step may provide a more compact form of laundry (the compressed laundry cake) being processed through the subsequent steps. This compression step may potentially improve the efficiency of the dewatering process by reducing the volume of the laundry and facilitating more effective heat transfer during the microwave and drying steps. Such laundry cakes may have dry weights of at least 25 kg, 30 kg, or 35 kg.

[0067] The subsequent steps are similar to those in Figure 1, but applied to the compressed laundry cake. The inspection step (Step A') is performed on the compressed laundry cake to determine the presence or absence of metal items. If no metal items are detected, the compressed laundry cake is subjected to microwaves (Step B') for preheating. Finally, the compressed laundry cake undergoes a drying step (Step C') to heat and at least partially dewater it.

[0068] Figure 3 illustrates a flowchart for a method of washing laundry. This method comprises eight steps: G, F, H, E, D, A', B', and C'.

[0069] Step G involves sorting laundry into at least one batch. This step may provide for the organization and categorization of laundry items before further processing. Laundry may be sorted based on attributes such as fabric type, colour, soil level, and specific care requirements. These attributes may influence how the laundry is washed and processed. The system may include sensors or input mechanisms to identify and categorize these attributes automatically or through user input. In some cases, the sorting step may also consider the presence of stains or Odors, and the washing step may be adapted by including pre-treatment steps or using specific stain-removal agents for these items.

[0070] Step F comprises weighing the batch of laundry. This step provides information about the batch that may be used to optimize subsequent processing steps.

[0071] Step H involves assigning a unique batch number to the batch of laundry. This step enables tracking and identification of the specific batch throughout the entire laundry processing cycle. In addition to the attributes mentioned under step G, various types of information may be collected for each specific batch of laundry. This information may include the origin or source of the laundry (e.g., hospital, hotel, restaurant), the date and time of collection, the total number of items in the batch, the presence of any special handling instructions, and any pre-treatment requirements. The system may also record environmental conditions such as ambient temperature and humidity at the time of processing. In some cases, information about the specific washing agents used, water consumption, and energy usage during the washing process may be collected. This comprehensive data collection may enable better tracking, process optimization, and quality control throughout the laundry processing cycle.

[0072] Step E involves washing the batch of laundry using at least one laundry washing device. The washing step may be adapted based on fabric type, colour, and soil level. For example, delicate fabrics may require gentler cycles with cooler water, while heavily soiled items may need longer cycles with warmer water and higher detergent concentrations. White laundry may be washed at higher temperatures with bleach-containing detergents, while dark colours may use cooler water and colour-safe detergents.

[0073] The subsequent steps correspond to those in Figure 2.

[0074] Figure 4 illustrates a flowchart for a method of washing laundry. This method comprises four steps: E, A, B, and C. Similar to the corresponding step of figure 3, in figure 4, step E involves washing the batch of laundry using at least one laundry washing device. Here, step E is further divided into four sub-steps: E1 - prewashing the batch of laundry, E2 - washing the batch of laundry, E3 - rinsing the batch of laundry, and E4 - neutralizing the batch of laundry.

[0075] Step E1 involves prewashing the batch of laundry. This initial washing step may help to remove loose dirt and debris from the laundry items, preparing them for more thorough cleaning in subsequent steps.

[0076] Step E2 comprises washing the batch of laundry. This involves the use of detergents and agitation to thoroughly clean the laundry items.

[0077] Step E3 involves rinsing the batch of laundry. This step helps to remove any remaining detergent and loosened dirt from the laundry items, ensuring they are clean and free from cleaning agents.

[0078] Step E4 involves neutralizing the batch of laundry. This final washing step may help to balance the pH of the laundry items, potentially improving their feel and longevity.

[0079] The subsequent steps correspond to those in Figure 1.

[0080] Figure 5 illustrates a system for dewatering batches of washed laundry 1. The system comprises an inspection device 11, a microwave radiation device 12, a conveyor 13, a laundry drying device 14, and a control unit 15. The control unit 15 is connected to the inspection device 11, microwave radiation device 12, and laundry drying device 14. This allows the control unit 15 to manage the operation of these components based on the inspection results and process parameters.

[0081] The conveyor 13 is shown transporting a compressed laundry cake 2 through the system. The compressed laundry cake 2 first passes through the inspection device 11, which examines the laundry for metal items. Next, the conveyor 13 moves the laundry cake 2 to the microwave radiation device 12, where it can be preheated if no metal items were detected. The conveyor 13 then transports the laundry cake 2 to the laundry drying device 14 for final drying. The system is arranged in a linear configuration, with the conveyor 13 moving the laundry cake 2 sequentially through each processing stage. This layout may enable continuous or semi-continuous dewatering of washed laundry batches.

[0082] The inspection device 11 may function to detect and identify metal items within the batch of washed laundry. It may utilize various detection technologies such as X-ray scanning, metal detectors, or electromagnetic sensors to examine the laundry. The inspection device 11 may send information to the control unit 15, including the presence or absence of metal items, their approximate size and location within the batch, and potentially the type of metal detected. This information may be used by the control unit 15 to make decisions about subsequent processing steps, such as whether to activate the microwave radiation device 12 or adjust parameters of the laundry drying device 14. In some cases, the inspection device 11 may also provide data on the overall composition and condition of the laundry batch, which the control unit 15 may use to optimize the dewatering process.

[0083] In some aspects, inspection device 11 may include an X-ray scanner. Said scanner may have a pixel resolution of at least 100 micrometres. The X-ray scanner may operate at energy levels of at least 80 k eV and may have adjustable X-ray energy levels. In some aspects, the X-ray energy level may be adapted based on factors such as the weight or dimensions of the laundry batch being inspected. This X-ray scanning capability may allow for examination of laundry batches to detect the presence of metal items prior to subsequent processing steps.

[0084] The microwave radiation device 12 may be designed to preheat batches of washed laundry as part of the dewatering process. In some aspects, the microwave radiation device 12 may include adjustable power settings and multiple magnetrons to provide heating across the laundry batch. The control unit 15 may regulate the operation of the microwave radiation device 12 based on various parameters. For instance, the control unit 15 may adjust the microwave power level, exposure time, and frequency based on factors such as the laundry batch size, fabric composition, and moisture content. In some cases, the control unit 15 may use feedback from temperature sensors within the microwave radiation device 12 to adjust the heating process, ensuring preheating without risking damage to the laundry items. The control unit 15 may also coordinate the activation and deactivation of the microwave radiation device 12 with the movement of the conveyor 13, ensuring that each batch of laundry receives the appropriate treatment as it passes through the system.

[0085] In some aspects, the microwave radiation device 12 may be configured to preheat the batch of laundry with microwaves having a wavelength of between 5 and 35 cm, preferably between 12 and 13 cm. The laundry drying device 14 may be designed to expose each batch of laundry to air having a temperature of between 40 and 100 degrees Celsius, or more specifically between 40 and 90 degrees Celsius. In some cases, the air temperature may be adjusted based on the specific requirements of the batch of laundry to be dewatered. These temperature and wavelength ranges may allow for preheating and drying of the laundry batches while potentially minimizing energy consumption and preventing damage to the laundry items.

[0086] The laundry drying device 14 may be designed to remove moisture from batches of washed laundry. In some aspects, it may utilize heated air circulation to facilitate the drying process. The laundry drying device 14 may incorporate adjustable temperature and airflow settings, allowing for customization based on the specific requirements of different laundry types. In some cases, the device may include sensors to monitor the moisture content of the laundry, enabling adjustment of the drying parameters. The control unit 15 may regulate the operation of the laundry drying device 14, potentially optimizing energy efficiency while ensuring drying of the laundry batches.

[0087] In some aspects, the inspection device 11, microwave radiation device 12, and laundry drying device 14 may each be configured to determine a batch identifier for the batch laundry it is currently about to process. These devices may send this batch identifier to the control unit 15. Based on the received batch identifiers, the control unit 15 may send specific instructions back to each of these device, tailoring the processing parameters for that particular batch of laundry. This system may allow for individualized treatment of each laundry batch as it moves through the dewatering process, potentially improving efficiency and quality of the overall operation.

[0088] Figure 6 illustrates a system for washing laundry. In addition to the elements shown in and discussed in relation to the system for dewatering batches of washed laundry 1 of figure 5, the system of figure 6 shows a sorting device 20, identifier assigning device 19, a weighing device 18, a laundry washing device 17, and dewatering press 16.

[0089] The sorting device 20 may be designed to organize and categorize laundry items before further processing. In some aspects, the sorting device 20 may incorporate sensors or input mechanisms to identify and categorize laundry attributes such as fabric type, colour, soil level, and specific care requirements. The device may also be capable of detecting the presence of stains or Odors, which may influence subsequent washing steps. In some cases, the sorting device 20 may interface with the control unit 15, providing information about each batch of laundry that may be used to optimize the washing and dewatering processes.

[0090] The identifier assigning device 19 may be designed to generate and assign unique batch numbers to each batch of laundry processed by the system. These unique batch numbers may correlate to properties of the laundry batch. In some aspects, this device may interface with other components of the system, such as the sorting device 20 and weighing device 18, to incorporate relevant information into the batch identifier. The identifier assigning device 19 may utilize technologies, such as barcode or RFID tag generation, to create physical or digital identifiers that can be attached to or associated with each laundry batch. In some cases, the device may also record and associate additional data with each batch identifier, such as processing timestamps, origin information, and specific handling instructions.

[0091] The weighing device 18 may be designed to measure the weight of each batch of laundry before it enters the washing process. In some aspects, the weighing device 18 may incorporate load cells or other measurement technologies to provide weight data. This information may be used by the control unit 15 to optimize subsequent processing steps, such as determining appropriate water levels, detergent amounts, and cycle durations in the laundry washing device 17. The weighing device 18 may also interface with the identifier assigning device 19, allowing the weight information to be associated with the unique batch number for each load of laundry. In some cases, the weighing device 18 may include features to accommodate various batch sizes and laundry types, ensuring consistent weight measurements throughout the laundry processing cycle.

[0092] The laundry washing device 17 may be designed to wash batches of laundry using at least one laundry washing device. The washing process may be adapted based on fabric type, colour, and soil level. For example, delicate fabrics may require gentler cycles with cooler water, while heavily soiled items may need longer cycles with warmer water and higher detergent concentrations. White laundry may be washed at higher temperatures with bleach-containing detergents, while dark colours may use cooler water and colour-safe detergents.

[0093] In some aspects, the laundry washing device 17 may be configured to perform the sub-steps E1-E4 introduced earlier. Specifically, laundry washing device 17 may be capable of prewashing the batch of laundry (E1), washing the batch of laundry (E2), rinsing the batch of laundry (E3), and neutralizing the batch of laundry (E4). The prewashing step may help remove loose dirt and debris, the washing step may involve the use of detergents and agitation for cleaning, the rinsing step may remove remaining detergent and loosened dirt, and the neutralizing step may help balance the pH of the laundry items.

[0094] The dewatering press 16 may be designed to compress batches of laundry, potentially reducing their volume and moisture content. In some aspects, the dewatering press 16 may be capable of performing step D, which involves compressing at least one batch of laundry to be dewatered, forming a compressed laundry cake. This compression process may help to remove excess water from the laundry, potentially improving the efficiency of subsequent dewatering steps in the system.

[0095] The application further provides the following clauses. 1. Method for dewatering batches of washed laundry, comprising the steps of: A) inspecting at least one batch of washed laundry to be dewatered by means of at least one inspection device to determine the presence or absence of one or more metal items in said batch of washed laundry to be dewatered, B) only in case during step A) no metal item is detected in said batch of washed laundry, subjecting said batch of washed laundry to microwaves, by using at least one microwave radiation device, to preheat said batch of washed laundry, and C) following step A) and conditionally following step B), subjecting said batch of washed laundry to at least one drying step, by using at least one laundry drying device, to heat and at least partially dewater said batch of washed laundry. 2. Method according to clause 1, wherein during step B) the batch of washed laundry is partially dewatered. 3. Method according to clause 1 or 2, wherein said at least one inspection device, said at least one microwave radiation device, and said at least one laundry drying device are positioned in series with each other allowing successive execution of step A), conditional step B), and step C), preferably in a continuous or semi-continuous manner. 4. Method according to any of the preceding clauses, wherein in case during step A) at least one metal item is detected in said batch of washed laundry, the batch of washed laundry is led through or along said at least microwave radiation device in non-operational state to the at least one laundry drying device prior to performing step C). 5. Method according to any of the preceding clauses, wherein conditional step B) is directly performed after completion of step A). 6. Method according to any of the preceding clauses, step C) is directly performed after conditional completion of step B) and / or after completion of step A). 7. Method according to any of the preceding clauses, wherein said batch of laundry is conveyed from the at least one inspection up to the laundry drying device by using at least one conveyor. 8. Method according to any of the preceding clauses, wherein the method comprises step D), comprising the step of compressing at least one, preferably each, batch of laundry to be dewatered during conditional step B) and step C), by using at least one dewatering press, wherein during step D) at least one compressed laundry in is formed. 9. Method according to clause 8, wherein step D) is performed prior to step A). 10. Method according to clause 8 or 9, wherein each laundry cake has a dry weight of at least about 25 kg, preferably at least 30 kg, more preferably at least 35 kg. 11. Method according to any of the preceding clauses, wherein the at least one inspection device used during step A) comprises at least one metal detector configured to determine the presence of absence of one or more metal items, such as for example metal buttons, metal clips, metal eyes, metal rivets, metal fasteners, metal hooks and eyes, metal chains, metal tags, metal logos, metal zippers, metal tools, and other metal particles, in each batch of laundry to be dewatered. 12. Method according to clause 11, wherein at least one metal detector comprises at least one x-ray scanner to determine the presence of absence of one or more metal items in each batch of laundry, wherein a pixel resolution of said x-ray scanner is preferably at least 100 micrometre. 13. Method according to clause 12, wherein during step A) an x-ray energy level of said x-ray scanner is at least 80 k eV is used. 14. Method according to clause 12 or 13, wherein during step A) an x-ray energy level of said x-ray scanner is adjustable, wherein the x-ray energy level is preferably adapted to the weight and / or dimensions of the batch of laundry. 15. Method according to any of the preceding clauses, wherein during step A) each batch of laundry is moved through the inspection device, by using at least one conveyor. 16. Method according to any of the preceding clauses, wherein during step B) a temperature, preferably a surface temperature, of the batch of laundry is measured, preferably by using at least one infrared sensor, wherein the preheating continues until a predefined temperature, preferably surface temperature, has been reached. 17. Method according to any of the preceding clauses, wherein step B) is performed during a predetermined amount of time. 18. Method according to any of the preceding clauses, wherein at least one microwave radiation device used during step B) comprises at least one shielded treatment chamber. 19. Method according to any of the preceding clauses, wherein during step B) the batch of laundry is preheated with microwaves having a wavelength of between 5 and 35 cm, preferably between 12 and 13 cm. 20. Method according to any of the preceding clauses, wherein during step B) the batch of laundry is moved, in particular rotated, preferably about a vertical axis, at least for a period of time during step B). 21. Method according to any one of the preceding clauses, wherein during conditional step B) humid air released from the batch of laundry is discharged from the microwave radiation device, and / or wherein during step C) humid air released from the batch of laundry is discharged from the laundry drying device. 22. Method according to any of the preceding clauses, wherein during step C) a temperature, preferably a surface temperature, of the batch of laundry is measured, preferably by using at least one infrared sensor, wherein the preheating continues until a predefined temperature, preferably surface temperature, has been reached. 23. Method according to any of the preceding clauses, wherein during step C) the humidity of the batch of laundry is measured, preferably by using at least one humidity sensor. 24. Method according to any of the preceding clauses, wherein during step C) each batch of laundry is at least partially dewatered by exposing said batch of laundry to air having a temperature of between 40 and 100 degrees Celsius, between 40 and 90 degrees Celsius, wherein the air temperature is preferably adjusted to the batch of laundry to be dewatered. 25. Method according to any of the preceding clauses, wherein step C) is performed during a predetermined amount of time. 26. Method according to any of the preceding clauses, wherein during step C) the batch of laundry is moved, preferably tumbled. 27. Method for washing batches of laundry, comprising the steps of: E) washing at least one batch of laundry, by using at least one laundry washing device, such as a batch washer or tunnel washer, followed by at least partially dewatering said batch of laundry washed according to step E) by applying the method according to any of the preceding clauses. 28. Method according to clause 27, wherein washing step E) comprises a plurality of sub steps, preferably including the two or more of the following sub steps: E1) prewashing, E2) washing, E3) rinsing, and E4) neutralizing the batch of laundry. 29. Method according to clause 27 or 28, wherein the method comprises step F) comprising the step of weighing each one batch of laundry prior to washing said batch of laundry according to step E). 30. Method according to clause 29, wherein the method comprises step G) comprising the step of sorting laundry prior to performing step F). 31. Method to any of the preceding clauses, wherein the method comprises to H) comprising the step of assigning a unique batch number to each batch of laundry, wherein said batch number is correlated to one or more properties of the particular batch of laundry, such as a the weight of said batch of laundry, and wherein step H) is performed prior to A, preferably prior to step E). 32. Method according to clause 31, wherein at least one control unit is provided which controls, based upon the unique batch number, the at least one inspection device during step A), and / or the at least one microwave radiation device during step B) in case no metal item is detected within said batch during step A), and / or the laundry drying device during step C). 33. System for dewatering batches of washed laundry, preferably by making use of a method according to any of the preceding clauses, comprising: at least one inspection device to determine the presence or absence of metal items in said batch of washed laundry to be dewatered, at least one microwave radiation device configured to subject said batch of washed laundry to microwaves, by to preheat said batch of washed laundry, at least one laundry drying device configured to heat and at least partially dewater said batch of washed laundry, and at least one control unit configured to activate said at least one microwave radiation device only in case said at least one inspection device determines for a particular batch of washed laundry that said batch of washed laundry is free or any metal item. 34. System according to clause 33, wherein the at least one microwave radiation device is configured to partially dewater the batch of washed laundry by preheating said batch of washed laundry. 35. System according to clause 33 or 34, wherein said at least one inspection device, said at least one microwave radiation device, and said at least one laundry drying device are positioned in series with each other allowing continuous or semi-continuous dewatering process of washed laundry. 36. System according to any of clauses 33-35, further comprising at least one conveyor configured to convey said batch of laundry from the at least one inspection device up to the laundry drying device, wherein said conveyor is preferably controlled by said control unit. 37. System according to any of clauses 33-36, wherein the system comprises at least one conveyor for transporting batches of washed laundry, wherein said conveyor is guided through or along said at least one microwave radiation device, wherein the control unit is configured to control the conveyor to guide batches of laundry successively through or along said at least one microwave radiation device, such that, dependent on the detected presence or absence of one or more metal items by the at least one inspection device for a particular batch of laundry, the at least one microwave radiation device is selectively switched off or on, respectively, for said particular batch of laundry. 38. System according to any of clauses 33-37, further comprising at least one dewatering press configured to compress at least one, preferably each, batch of laundry to be dewatered during operation of the at least one microwave radiation device and the at least one laundry drying device, wherein the at least one dewatering press is configured to form at least one compressed laundry cake. 39. System according to any of clauses 33-38, wherein the system is configured to process and / or form laundry cakes having a dry weight of at least about 25 kg, preferably at least 30 kg, more preferably at least 35 kg. 40. System according to any of clauses 33-39, wherein the at least one inspection device comprises at least one metal detector configured to determine the presence or absence of one or more metal items in each batch of laundry to be dewatered. 41. System according to clause 40, wherein the at least one metal detector comprises at least one x-ray scanner to determine the presence or absence of one or more metal items in each batch of laundry, wherein a pixel resolution of said x-ray scanner is preferably at least 100 micrometres. 42. System according to clause 41, wherein the x-ray scanner is configured to operate at an x-ray energy level of at least 80 k eV. 43. System according to clause 41 or 42, wherein the x-ray scanner is configured with an adjustable x-ray energy level, wherein the x-ray energy level may be adapted to the weight and / or dimensions of the batch of laundry. 44. System according to any of clauses 33-43, wherein at least one microwave radiation device comprises at least one temperature sensor, preferably an infrared sensor, configured to measure a temperature, preferably a surface temperature, of the batch of laundry during operation of the at least one microwave radiation device, wherein the system, in particular the control unit and / or the microwave radiation device, is configured to continue preheating until a predefined temperature, preferably surface temperature, has been reached. 45. System according to any of clauses 33-44, wherein the at least one microwave radiation device comprises at least one shielded treatment chamber. 46. System according to any of clauses 33-45, wherein the at least one microwave radiation device is configured to preheat the batch of laundry with microwaves having a wavelength of between 5 and 35 cm, preferably between 12 and 13 cm. 47. System according to any of clauses 33-46, wherein the system, in particular a conveyor of the system, is configured to move, in particular rotate, preferably about a vertical axis, the batch of laundry at least for a period of time during subjecting said batch of laundry to the at least one microwave radiation device. 48. System according to any of clauses 33-47, wherein the at least one microwave radiation device is configured to discharge humid air released from the batch of laundry, and / or wherein the laundry drying device is configured to discharge humid air released from the batch of laundry from the laundry drying device. 49. System according to any of clauses 33-48, wherein the at least one laundry drying device comprises at least one temperature sensor, preferably an infrared sensor, configured to measure a temperature, preferably a surface temperature, of the batch of laundry during operation of the at least one laundry drying device, wherein the system, in particular the control unit and / or the laundry drying device, is configured to continue drying until a predefined temperature, preferably surface temperature, has been reached. 50. System according to any of clauses 33-49, wherein the at least one laundry drying device comprises at least one humidity sensor configured to measure the humidity of the batch of laundry during operation of the at least one laundry drying device. 51. System according to any of clauses 33-50, wherein the at least one laundry drying device is configured to expose each batch of laundry to air having a temperature of between 40 and 100 degrees Celsius, between 40 and 90 degrees Celsius, wherein the air temperature may be adjusted to the batch of laundry to be dewatered. 52. System according to any of clauses 33-51, wherein at least one laundry drying device is configured to move, preferably tumble, the batch of laundry during operation of said at least one laundry drying device. 53. System according to any of clauses 33-52, wherein the system comprises at least one laundry washing device, wherein said at least one laundry washing device is preferably a batch washer or a tunnel washer or a continuous washer. 54. System according to clause 53, wherein the at least one laundry washing device is configured to perform a plurality of sub steps, preferably including two or more of the following sub steps: prewashing, washing, rinsing, and neutralizing the batch of laundry. 55. System according to any of clauses 53-54, further comprising at least one weighing device configured to weigh each batch of laundry prior to washing said batch of laundry. 56. System according to clause 55, further comprising at least one sorting device configured to sort laundry prior to weighing by the at least one weighing device. 57. System according to any of clauses 33-56, wherein the system, in particular the control unit, is configured to assign a unique batch number to each batch of laundry, wherein said batch number is correlated to one or more properties of the particular batch of laundry, such as the weight of said batch of laundry, and wherein said unique batch number and said correlated one or more properties are stored by the control unit and / or onto a digital storage memory of the system. 58. System according to clause 57, wherein the at least one control unit is configured to control, based upon the unique batch number, the at least one inspection device, and / or the at least one microwave radiation device in case no metal item is detected within said batch by the at least one inspection device, and / or the laundry drying device. 59. Use or intended use of a microwave radiation device to preheat batches of laundry to be dewatered in a method according to any of clauses 1-32 and / or system according to any of clauses 33-58.

[0096] The embodiments, configurations, and examples presented in this specification are provided by way of illustration and should not be considered as limiting the scope of the invention. It will be understood that various modifications, substitutions, and adaptations may be made without departing from the scope and spirit of the invention.

[0097] The specific features described may be used independently of other features or in combination with other features, and any one or more features disclosed in this specification may be combined in various ways, reconfigured, or omitted altogether. Such combinations or modifications, including those involving individual features isolated from an embodiment or rearranged into new configurations, are within the scope of the invention as long as they do not depart from the fundamental principles and objectives of the invention.

[0098] Furthermore, those skilled in the art will appreciate that alternative embodiments, variations, and equivalents to the described components and processes can be developed based on the teachings provided herein. All such alternative embodiments, variations, and new combinations of isolated features that are functionally equivalent or achieve substantially the same results are intended to be included within the scope of the appended claims, whether or not explicitly mentioned.

Claims

1. Method for dewatering batches of washed laundry, comprising the steps of: D) inspecting at least one batch of washed laundry to be dewatered by means of at least one inspection device to determine the presence or absence of one or more metal items in said batch of washed laundry to be dewatered, E) only in case during step A) no metal item is detected in said batch of washed laundry, subjecting said batch of washed laundry to microwaves, by using at least one microwave radiation device, to preheat said batch of washed laundry, and F) following step A) and conditionally following step B), subjecting said batch of washed laundry to at least one drying step, by using at least one laundry drying device, to heat and at least partially dewater said batch of washed laundry; wherein said at least one inspection device, said at least one microwave radiation device, and said at least one laundry drying device are positioned in series with each other allowing successive execution of step A), conditional step B), and step C), preferably in a continuous or semi-continuous manner.

2. Method according to claim 1, wherein in case during step A) at least one metal item is detected in said batch of washed laundry, the batch of washed laundry is led through or along said at least microwave radiation device in non-operational state to the at least one laundry drying device prior to performing step C).

3. Method according to claim 1 or 2, wherein the method comprises step D), comprising the step of compressing at least one, preferably each, batch of laundry to be dewatered during conditional step B) and step C), by using at least one dewatering press, wherein during step D) at least one compressed laundry in is formed; wherein preferably step D) is performed prior to step A), and / or wherein preferably each laundry cake has a dry weight of at least about 25 kg, preferably at least 30 kg, more preferably at least 35 kg.

4. Method according to any of the preceding claims, wherein the at least one inspection device used during step A) comprises at least one metal detector configured to determine the presence of absence of one or more metal items, such as for example metal buttons, metal clips, metal eyes, metal rivets, metal fasteners, metal hooks and eyes, metal chains, metal tags, metal logos, metal zippers, metal tools, and other metal particles, in each batch of laundry to be dewatered.

5. Method according to claim 4, wherein at least one metal detector comprises at least one x-ray scanner to determine the presence of absence of one or more metal items in each batch of laundry, wherein a pixel resolution of said x-ray scanner is preferably at least 100 micrometre; wherein preferably during step A) an x-ray energy level of said x-ray scanner is: - at least 80 k eV is used, and / or - adjustable, wherein the x-ray energy level is more preferably adapted to the weight and / or dimensions of the batch of laundry.

6. Method according to any of the preceding claims, wherein during step A) each batch of laundry is moved through the inspection device, by using at least one conveyor.

7. Method to any of the preceding claims, wherein the method comprises to H) comprising the step of assigning a unique batch number to each batch of laundry, wherein said batch number is correlated to one or more properties of the particular batch of laundry, such as a the weight of said batch of laundry, and wherein step H) is performed prior to A, preferably prior to step E); wherein preferably at least one control unit is provided which controls, based upon the unique batch number, the at least one inspection device during step A), and / or the at least one microwave radiation device during step B) in case no metal item is detected within said batch during step A), and / or the laundry drying device during step C).

8. System for dewatering batches of washed laundry, preferably by making use of a method according to any of the preceding claims, comprising: - at least one inspection device to determine the presence or absence of metal items in said batch of washed laundry to be dewatered, - at least one microwave radiation device configured to subject said batch of washed laundry to microwaves, by to preheat said batch of washed laundry, - at least one laundry drying device configured to heat and at least partially dewater said batch of washed laundry, and - at least one control unit configured to activate said at least one microwave radiation device only in case said at least one inspection device determines for a particular batch of washed laundry that said batch of washed laundry is free or any metal item wherein said at least one inspection device, said at least one microwave radiation device, and said at least one laundry drying device are positioned in series with each other allowing continuous or semi-continuous dewatering process of washed laundry.

9. System according to claim 8, further comprising at least one conveyor configured to convey said batch of laundry from the at least one inspection device up to the laundry drying device, wherein said conveyor is preferably controlled by said control unit.

10. System according to claim 8 or 9, wherein the system comprises at least one conveyor for transporting batches of washed laundry, wherein said conveyor is guided through or along said at least one microwave radiation device, wherein the control unit is configured to control the conveyor to guide batches of laundry successively through or along said at least one microwave radiation device, such that, dependent on the detected presence or absence of one or more metal items by the at least one inspection device for a particular batch of laundry, the at least one microwave radiation device is selectively switched off or on, respectively, for said particular batch of laundry.

11. System according to claim 8, 9 or 10, wherein the at least one inspection device comprises at least one metal detector configured to determine the presence or absence of one or more metal items in each batch of laundry to be dewatered.

12. System according to claim 11, wherein the at least one metal detector comprises at least one x-ray scanner to determine the presence or absence of one or more metal items in each batch of laundry, wherein a pixel resolution of said x-ray scanner is preferably at least 100 micrometres; wherein the x-ray scanner is preferably configured: - to operate at an x-ray energy level of at least 80 k eV; and / or - with an adjustable x-ray energy level, wherein the x-ray energy level may be adapted to the weight and / or dimensions of the batch of laundry.

13. System according to any one of the claims 8-12, further comprising at least one weighing device configured to weigh each batch of laundry prior to washing said batch of laundry; preferably further comprising at least one sorting device configured to sort laundry prior to weighing by the at least one weighing device.

14. System according to any of claims 8-13, wherein the system, in particular the control unit, is configured to assign a unique batch number to each batch of laundry, wherein said batch number is correlated to one or more properties of the particular batch of laundry, such as the weight of said batch of laundry, and wherein said unique batch number and said correlated one or more properties are stored by the control unit and / or onto a digital storage memory of the system; wherein the at least one control unit is preferably configured to control, based upon the unique batch number, the at least one inspection device, and / or the at least one microwave radiation device in case no metal item is detected within said batch by the at least one inspection device, and / or the laundry drying device.

15. Use or intended use of a microwave radiation device to preheat batches of laundry to be dewatered in a method according to any of claims 1-7 and / or system according to any of claims 8-14.

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