Cooling function for measuring systems for determining a roller gap

Abstract

According to one aspect of the invention, a roller system for sealing or processing a medical product, in particular a flat medical product, is provided. The roller system comprises a first roller and a second roller, which are rotatably mounted at a variable roller spacing to one another and are designed to generate a contact pressure for sealing or processing the medical product, and the roller system further comprises a sensor for monitoring the roller spacing, a heating device for heating the roller system, and a fluid connection for providing a cooling fluid for cooling the sensor.

Description

[0001] Cooling of measuring systems for determining a roller gap

[0002]

[0001] The invention relates to a roller system for sealing or processing a medical product, as well as a corresponding device and method.

[0003] Technical background

[0004]

[0002] In the manufacture of medical products, especially sterile-packaged products such as bandages, plasters, wound dressings, swabs, and medical face masks, particular emphasis must be placed on secure packaging. The packaging should enclose the hygiene product as germ-proof as possible. In summary, the product to be packaged is placed between two layers of material, which are welded together in a designated sealing station.

[0005]

[0003] Such a sealing station is described, for example, in WO 2022 / 078636. The system described therein comprises a pair of pressure rollers arranged at a distance from each other. One of the two pressure rollers is made of steel and the other of silicone. The product is stacked between two webs of material and guided through the roller gap so that the product can be sealed by forming a sealing seam. This sealing station can achieve a material throughput speed of around 200 m / min.

[0006]

[0004] However, problems arose with the quality of the seal. The distance between the rollers through which the material webs with the product in between pass proved to be a relevant parameter. Especially when using two steel rollers, the roller distance is the decisive process parameter for the contact pressure of the sealing material.

[0007]

[0005] The invention is applicable to any type of system for packaging medical products in which one or more continuous webs of material and / or other components pass through two opposing rollers in order to be compressed between them. In the simplest case, the invention is applicable to a system with two opposing rollers, wherein one or more webs of material are guided through the rollers or the distance between the rollers, and at least one of the rollers processes the material being guided through.

[0008] Summary

[0009]

[0006] There is therefore a need for a roller system that can seal or produce medical products with improved quality without having to accept any reduction in material throughput speed.

[0010]

[0007] It is a further object of the invention to provide a roller system that at least partially solves the problems known in the prior art.

[0011]

[0008] At least one of these problems is solved by the roller system, the device, and the method according to the independent claims. Further developments of the invention are specified in the respective dependent claims.

[0012]

[0009] According to one aspect of the invention, a roller system is provided for sealing or processing a medical product, in particular a flat medical product. The roller system comprises a first roller and a second roller, which are rotatably mounted at a variable roller distance from each other and are configured to generate a contact pressure for sealing or processing the medical product. Furthermore, the roller system comprises one or more sensors for detecting the position and / or diameter of the first roller or for monitoring the roller position, a heating device for heating the roller system, and a fluid connection for supplying a cooling fluid for cooling the sensor.

[0013]

[0010] By measuring the position, diameter, and / or roller gap, the contact pressure on the material or sealing material can be monitored and adjusted. For example, the ideal distance between the two rollers can be 80 pm at a roller temperature of 150°C. In the following, the terms roller gap and roller distance are used synonymously. The values ​​for temperature and roller gap are given here only as examples.

[0014]

[0011] The provision of the fluid connection also enables the use of sensors that are not designed for the temperatures in operation of the roller system, but ensure a more precise detection of the position and / or diameter of the first roller or monitoring of the roller system.

[0015]

[0012] During operation of the roller system, the roller spacing can vary, in particular due to material wear, a positional shift of the first roller and / or temperature changes, in some cases unpredictably.

[0016]

[0013] This monitoring makes it possible to continuously monitor the quality of the seal or the material being processed, i.e. to determine for each medical product either a sufficient quality, e.g. in the sealing, or, if necessary, to sort out inadequate products or products of low quality.

[0017]

[0014] Furthermore, based on monitoring the roller position during operation, the roller gap can be corrected or adjusted if the optical sensor detects a roller gap that is outside a tolerance range. This can significantly reduce the reject rate of insufficiently sealed or processed products. In other words, correcting the roller position allows for quality improvement in the sealing or processing process.

[0018]

[0015] In one embodiment of the roller system, the sensor can be designed as an optical sensor, preferably as a photoelectric sensor, and in particular as an optical micrometer. The sensor can comprise a transmitter and a receiver, which can be arranged facing each other on opposite sides of the first roller.

[0019]

[0016] Capacitive distance sensors (capacitive area sensors) are generally suitable for accurately measuring the roller gap. These are inexpensive to manufacture and insensitive to high temperatures.

[0020]

[0017] However, a capacitive sensor can only measure up to a maximum distance of approximately 1 mm. Since the upper roller is raised by considerably more than 1 mm when the system is at a standstill, for example by up to 28 mm, and therefore the roller gap increases considerably, capacitive sensors alone are unsuitable for monitoring the roller gap.

[0021]

[0018] Providing at least one optical sensor for monitoring the roll position has the advantage that it has a significantly larger measuring range, namely a measuring span of approximately 3 pm to 100 mm, preferably up to 50 mm, and particularly preferably up to 40 mm. This allows larger variations or deviations from a predetermined roll distance to be detected, so that the roll distance can be continuously or online monitored as a process parameter. The measuring accuracy of the optical sensor, for example a micrometer, can be approximately 1 / 3 µm.

[0022]

[0019] In other words, the gap between the first and second rollers is crucial for the contact pressure on the material between the rollers. The optical sensor, or multiple optical sensors, are provided or arranged in the roller system to monitor this gap not only when the roller system is stationary using feeler gauges, but also during the ongoing process.

[0023]

[0020] The light barrier sensor is an optoelectronic system that forms a light beam between the transmitter and the receiver. The light barrier sensor can detect an interruption of the light beam and indicate it as an electrical signal. The transmitter can comprise at least one light source, and the receiver can comprise at least one photodiode or phototransistor. Light-emitting diodes (LEDs) with a wavelength of 660 nm (visible red light) or infrared LEDs with a wavelength of 880–940 nm in the infrared range can be used as the light source.

[0024]

[0021] In one embodiment, the transmitter can generate a beam of light or a bundle of light beams, such as a light curtain, directed towards the receiver. Advantageously, the transmitter can generate a bundle of light beams with a diameter of preferably 30-50 mm, more preferably 40 mm. In one embodiment, the transmitter can be configured to generate a cuboid or circular bundle of light beams with a width of preferably 30-50 mm, more preferably 40 mm.

[0025]

[0022] When the first roller interrupts the light beam or at least partially interrupts the light beam bundle, the receiver can detect and receive a change in light intensity and convert it into an electrical switching signal. In one embodiment, the light beam or light beam bundle can be modulated to distinguish it from ambient light. Furthermore, an infrared filter can be provided in front of the receiver to block higher-frequency light (including the visible component of daylight).

[0026]

[0023] In one embodiment, one or each of the optical sensor(s) can be configured as an optical micrometer, having a measuring range of 40 mm, a resolution of 0.2 pm, a linearity of less than or equal to 0.01 pm, and a measuring frequency of up to 5 kHz. The receiver can be configured to generate a black-and-white image for aligning the measuring range using a scale. The transmitter and the receiver can be spaced approximately 300 mm apart.

[0027]

[0024] In one embodiment, the contact pressure is essentially determined by the roller spacing. The first roller and the second roller can also be referred to as pressure rollers.

[0028]

[0025] In one embodiment, the roller system can be adapted to seal the medical product in a germ-tight manner.

[0029]

[0026] In another embodiment, the roller system can be adapted to emboss or cut the medical product.

[0030]

[0027] In one embodiment, the optical sensor(s) can be configured to measure the position and / or diameter of the first and second rollers. For this purpose, one or each of the optical sensor(s) can comprise a transmitter, a first receiver, and a second receiver. The optical sensor can further comprise an at least partially reflective element or reflector by means of which a light beam or optical signal from the transmitter can be at least partially reflected or directed towards the first receiver and / or the second receiver. For this purpose, the reflector can be arranged opposite the transmitter such that one of the two rollers, by expansion and / or displacement, enters the space between the transmitter and the reflector. The first receiver can be arranged behind the reflector or at a distance from the transmitter opposite the reflector.The second receiver can be positioned at a distance from the transmitter, relative to the reflector, such that the other cylinder can enter the space between the reflector and the second receiver by expansion and / or displacement. In one embodiment, the reflector is a beam splitter that, depending on the polarization or wavelength, divides the transmitter's light beam into a transmissive partial beam and a reflective partial beam, wherein the transmissive partial beam can reach the first receiver and the reflective partial beam can reach the second receiver. In an alternative embodiment, the reflector is configured to divide the transmitter's light beam into two reflective partial beams. The first reflective partial beam can reach the first receiver and the second reflective partial beam can reach the second receiver.

[0031]

[0028] In one embodiment, the first roller and / or the second roller can optionally include a heating element. Additionally, the sealing material can be preheated before entering the roller gap.

[0032]

[0029] Heating the roller system prepares the sealing material for sealing. In particular, an adhesive of the sealing material can be thermally activated.

[0033]

[0030] The process temperature for sealing a medical product can be in the range of 50-100 °C, preferably in the range of 60-70 °C. By means of the heating device, and preferably in combination with preheating the sealing material, the sealing material can reach the process temperature in the area around and within the roller gap. Accordingly, the entire roller system can be heated during operation, so that even the holding device for the pair of pressure rollers can reach a temperature of approximately 70 °C. Therefore, not only can the roller gap be influenced by changes in the diameter of the heated rollers, but also by changes, i.e., expansion or contraction, of the holding device due to the heating of the entire roller system. The two rollers can be heated to a temperature of approximately 150 °C during operation.In particular, the holding device and the rollers can be heated to different temperatures during operation, so their relative expansion can also affect the roller spacing.

[0034]

[0031] However, the optical sensor is not usually designed for such temperatures. Therefore, the optical sensor can be actively cooled locally using a cooling fluid, for example, compressed air. The compressed air can be adjusted, for example, using a pressure reducer to allow greater heat exchange in the air duct.

[0035]

[0032] In one embodiment, the cooling fluid can comprise an airflow that can have a temperature in the range of 15°C to 30°C, preferably 15°C to 20°C, and even more preferably approximately 18°C. The airflow can be formed from compressed air.

[0036]

[0033] In one embodiment, the roller system can further comprise a hollow structure through which the cooling fluid can be guided. The cooling fluid can be directed through the hollow structure to actively cool the sensor.

[0034] In another embodiment, the roller system can further comprise a holding device in which the first roller and the second roller are rotatably mounted, in particular rotatably mounted in opposite directions. The optical sensor can be arranged on the holding device by means of a support device. The hollow structure can include a cooling channel in the support device.

[0037]

[0035] The optical sensor can be thermally coupled to the mounting device via the mounting device. Active cooling of the carrier or mounting device can at least partially prevent or slow down heat conduction from the mounting device, which heats up during operation, to the optical sensor. In other words, by directing the airflow through the cavity, the heat absorbed by the mounting device can be at least partially dissipated before the mounting device can transfer the heat to the optical sensor. This allows the temperature of the optical sensor to be limited, for example, to below 50 °C, thus ensuring the continued functionality of the optical sensor.

[0038]

[0036] In one embodiment, the cooling channel in the carrying device can extend along the direction of the greatest extent of the carrying device, preferably along the longitudinal direction of the carrying device.

[0039]

[0037] The transmitter and receiver of the optical sensor can be arranged on the carrying device. The carrying device can align the transmitter and receiver axially. The distance between the transmitter and receiver can be between 200 and 400 mm, preferably 300 mm. The cooling channel can extend parallel to the axis connecting the transmitter and receiver. Such a cooling channel enables particularly efficient cooling of the carrying device. In one embodiment, the cooling channel can be designed as a through-hole.

[0040]

[0038] In one embodiment, the roller system can further include a pressure reducer which is arranged downstream of the optical sensor in the cooling fluid flow.

[0041]

[0039] A pressure reducer, also known as a pressure regulator or pressure reducing valve, can regulate the compressed air flow and reduce the outlet pressure to the desired level. Due to the lower pressure of the cooling fluid, the cooling fluid can have a longer contact time with the support device and thus absorb and dissipate heat from the support device more efficiently.

[0042]

[0040] In one embodiment, the roller system can further comprise a temperature sensor for monitoring the temperature of the optical sensor and a processing unit. The processing unit can be configured to control the flow rate of the cooling fluid based on the temperature of the optical sensor.

[0043]

[0041] In one embodiment, the roller system can further comprise one or more additional sensors, particularly preferably a capacitive sensor. The additional sensor(s) can be configured to detect the position and / or diameter of the second roller. This can further increase the accuracy in determining the roller position.

[0044]

[0042] Instead of a direct gap measurement in front of the rollers, which is difficult anyway due to the material passing through the roller gap, the roller distance can be determined indirectly from the detected positions and / or detected diameters.

[0045]

[0043] By assigning the optical sensor to the first roller and a further, additional sensor to the second roller, the relevant roller parameters, i.e. their position and / or diameter, can be determined independently of each other, thereby increasing the measurement accuracy for the roller distance or reducing a statistical measurement error.

[0046]

[0044] According to a further aspect of the invention, a device for sealing a medical product is provided. The device comprises a means for supplying sealing material and the medical product, a means for generating and / or providing a cooling fluid, and a roller system as described above.

[0047]

[0045] In one embodiment, the sealing material can comprise an adhesive, wherein the adhesive can be activated by means of the heating device of the roller system. The sealing material can be adhesively attached by the contact pressure in order to seal the medical product in a germ-tight manner.

[0048]

[0046] According to a further aspect of the invention, a method for germ-tight sealing of a medical product is provided using a device described above. The method comprises the following steps:

[0049] Supplying the sealing material and the medical product,

[0050] Activating the sealing material,

[0051] Cooling one or each sensor,

[0052] Detecting the position of the first roller by means of one or more sensors, preferably optical sensors, wherein the position of the first roller represents the roller spacing, and

[0053] Monitoring the roller gap.

[0054]

[0047] In one embodiment, the distance between the first roller and the second roller can be determined from the detected position and / or the detected diameter. For this purpose, it is assumed that the position and diameter of the second roller are fixed or sufficiently constant. For this, the second roller can, for example, be made of a material that has a consistently low coefficient of thermal expansion at temperatures up to approximately 200 °C, such as glass-ceramic materials. In this embodiment, the position of the second roller, or the surface of the second roller opposite the first roller, can serve as a reference point for determining the roller gap. That is, the roller gap can be determined from the difference between the detected position of the first roller and the reference point.

[0055]

[0048] In one embodiment, the position of the first roll can be determined by the highest position of the roll shell within the roll system. This highest position of the roll shell can change due to a displacement of the first roll and / or an expansion or contraction of the first roll. Since, in this embodiment, the roll spacing is indirectly determined by detecting the highest point of the roll shell, either the diameter of the first roll or its position must be considered constant. The roll gap can be determined as follows: If the diameter of the first roll is constant, e.g., at a constant roll temperature, the roll gap can be determined from the difference between the detected position, the diameter of the first roll, and the highest point of the second roll.Provided the position of the first roller is fixed and the position of its center point is known, the roller gap can be determined in two steps when the diameter changes: First, the new roller radius can be calculated from the difference between the measured position and the center point of the first roller. Then, the roller gap can be determined by calculating the difference between the measured position and twice the new radius or diameter. In this way, the roller spacing can be continuously recalculated, thus minimizing potential error propagation.

[0056]

[0049] In one embodiment, the roller system can further include a storage unit in which a lookup table for the roller gap is stored. The lookup table can relate the recorded position of the first roller to a relative change in the roller gap. For this purpose, the roller gap can be recorded for different positions of the first roller, different roller temperatures, and / or different diameters of the roller system and stored in the lookup table. To determine the roller gap, for example, an initial roller distance can be manually measured and stored. During packaging operations, the resulting change in the roller gap can be read from relative changes in the position of the first roller, such as the highest point of the roller shell, using the lookup table.If the axis of rotation of the first roll is kept constant, the relative change in the measured position of the first roll can be applied to the existing roll gap to determine the new roll gap, due to the rotational symmetry of the roll. Similarly, if the roll temperature is constant, the relative displacement of the axis of rotation of the first roll can be applied to the existing roll gap to determine the new roll gap.

[0057]

[0050] In one embodiment, cooling the optical sensor can further include:

[0058] Inflow of the cooling fluid into the roller system, and reduction of the pressure of the cooling fluid downstream before cooling the sensor.

[0059]

[0051] By reducing the pressure of the cooling fluid, in particular a compressed air flow as cooling fluid, the cooling fluid can couple better to the structure of the roller system to be cooled, so that the temperature of the optical sensor can be cooled more efficiently.

[0060]

[0052] In one embodiment, cooling the optical sensor can further include:

[0061] - Determining the temperature of the optical sensor, and

[0062] - Controlling the flow rate of the cooling fluid based on the temperature of the sensor.

[0063]

[0053] In an embodiment in which the roller system includes the additional sensor, the method may further comprise:

[0064] Capture (S3) 1 ) the position of the second roller (20), and

[0065] Determine (S5) the roller position from a difference between the detected position of the first roller (10) and the detected position of the second roller (20).

[0066]

[0054] By detecting the position and / or diameter of the second roller, the reference point for determining the roller gap can change during the machining process. In one embodiment, the lookup table can further include the values ​​for the roller gap as a function of the position and / or diameter of the second roller. In another embodiment, the additional sensor can be designed as a capacitive sensor, which can be arranged directly below the second roller. This allows the additional sensor to detect the lowest point of the second roller's surface as the position of the second roller. In another embodiment, the axis of rotation of the second roller is fixed, so that a change in the roller gap due to the second roller is only accompanied by a change in the volume of the second roller.In this embodiment, the additional sensor can also be arranged laterally to the side of the second roller, so that the detected position of the second roller is a lateral point on the outer surface of the second roller.

[0067]

[0055] According to a further aspect of the invention, a roller system for sealing a medical product, in particular a flat medical product, is provided. The roller system comprises a first roller and a second roller, which are rotatably mounted at a variable roller distance from each other and are configured to generate a contact pressure for sealing the medical product. The roller system also includes one or more optical sensors for monitoring the roller distance.

[0068]

[0056] In one embodiment, the roller system can include a further sensor. The optical sensor can be configured to detect the position and / or diameter of the first roller, and the further sensor can be configured to detect the position and / or diameter of the second roller. The roller spacing can be determined from the detected positions and / or diameters.

[0069]

[0057] In a particularly preferred embodiment, one or each of the further sensor(s) can be a capacitive sensor, in particular a capacitive area sensor, wherein a rotational axis of the second roller can be fixed in place. The capacitive sensor can be positioned at a predetermined distance from the second roller, in particular positioned below the second roller. The predetermined distance should be within the measuring range of the capacitive sensor. One or each of the further sensors can be arranged on the holding device by means of a further carrier, wherein the further carrier can include an air duct, in particular analogous to the carrier of the optical sensor, in order to actively cool the further sensor(s).

[0070]

[0058] In one embodiment, the capacitive sensor can be arranged on a side of the second roller that is facing away from a material contact or sealing material contact, preferably on the side of the second roller opposite the contact or below the second roller.

[0071]

[0059] Due to the fixed position or the lack of adjustability of the second roller, its position can be considered essentially constant. However, the roller system can be temperature-controlled, particularly heated, for processing or sealing the medical product, which can cause the roller diameters to change. This is particularly problematic when rollers made of different materials are used. For example, if the second roller is made of steel, it can expand at operating temperatures of the roller system of approximately 70–150°C compared to the roller diameter at room temperature. A change in the roller diameter directly affects the roller spacing and consequently the contact pressure.

[0072]

[0060] The capacitive sensor is designed to detect the distance to a surface of an object facing the sensor by measuring changes in capacitance. For this purpose, the capacitive sensor has electrodes that can generate an electric field. As soon as the object enters the measuring range of the capacitive sensor, it changes the electric field, and thus the capacitance. The sensor is designed to detect the change in capacitance and convert it into an electrical signal, from which the distance can be calculated.

[0061] In one embodiment, the capacitive sensor can have a maximum measuring range of 1 mm, a resolution of at most 0.2 pm, a linearity of less than or equal to 0.05 pm, and a measuring frequency of up to 20 kHz. The roller system can include a demodulator for processing the signal from the capacitive sensor.

[0073]

[0062] In one embodiment, the medical product can be pressed together and sealed between at least two layers or webs of sealing material by means of embossing structures arranged on the first roller and / or the second roller. However, one or both rollers can also have recesses into which the medical product is pressed.

[0074]

[0063] The roller spacing can be defined as the smallest distance between the (shell) surface of the first roller and the (shell) surface of the second roller or as the smallest distance between the corresponding embossing structures of the first roller and the second roller.

[0075]

[0064] In one embodiment, the first roller and / or the second roller can have recesses, in particular corresponding recesses, on their outer surface.

[0076]

[0065] In one embodiment, the roller system can further comprise a holding device in which the first roller and the second roller are rotatably mounted. The first roller and the second roller are, in particular, rotatably mounted in opposite directions. An axis of rotation of the first roller can be displaceable perpendicular or vertically to the second roller, and in particular, be continuously displaceable. The optical sensor can be arranged on the holding device, and in particular, positioned above or below the first roller.

[0077]

[0066] An arrangement of the optical sensor above or below the first roller has the advantage that the position of the first roller can be continuously detected even when its axis of rotation is moved, for example to change the material webs.

[0078]

[0067] In one embodiment, the optical sensor can be arranged between the first roller and the second roller, or can send its optical signal between the first roller and the second roller.

[0079]

[0068] In one embodiment, the optical sensor can be arranged on a side of the first roller that is opposite a sealing material contact of the first roller.

[0080]

[0069] In one embodiment, the first roller forms an upper roller of the roller pair and the second roller forms the lower roller of the roller pair.

[0081]

[0070] In one embodiment, the first roller and the second roller are arranged vertically one above the other.

[0082]

[0071] In one embodiment, the holding device can be designed as a frame, wherein the first roller and the second roller can be arranged vertically one above the other, and wherein the capacitive sensor can be arranged in a lower section of the frame and the optical sensor can be arranged in an upper section of the frame.

[0083]

[0072] In one embodiment, the roller system can further include a heating device for heating the roller system. Likewise, the roller system can have a fluid connection for providing a cooling fluid for cooling the optical sensor, wherein the cooling fluid has a temperature in the range of 15°C to 30°C, preferably 15°C to 20°C, and even more preferably approximately 18°C.

[0073] In one embodiment, the optical sensor can be arranged on the holding device by means of a carrier. The carrier can include a cavity, and the fluid connection can be adapted to direct an airflow at least section by section through the cavity of the carrier.

[0084]

[0074] The optical sensor can be thermally coupled to the mounting device via the carrier. Active cooling of the carrier can at least partially prevent or slow down heat conduction from the mounting device, which heats up during operation, to the optical sensor. In other words, by directing the airflow through the cavity, the heat absorbed by the carrier can be at least partially dissipated before the carrier can transfer the heat to the optical sensor. This allows the temperature of the optical sensor to be limited, for example, to below 50 °C, thus ensuring the continued functionality of the optical sensor.

[0085]

[0075] In one embodiment, the roller system can further comprise a processing unit configured to receive the detected position and / or diameter of the first roller. If the roller system includes the additional sensor, the processing unit can alternatively or additionally receive the detected position and / or diameter of the second roller. The processing unit can be configured to determine the roller spacing based on the received first position or diameter and / or the received second position or diameter.

[0086]

[0076] In one embodiment, the processing unit can further be configured to control the position of the first roll. In this embodiment, the processing unit can be configured to control the roll gap based on the determined roll spacing, for example, by changing the position of the first roll. Should the determined roll spacing fall below a predetermined minimum threshold, for example, due to thermal expansion of the first roll and / or the second roll, the processing unit can intervene and increase the roll gap accordingly, e.g., by raising the first roll. Correspondingly, the processing unit can reduce the roll gap if the determined roll spacing exceeds a predetermined maximum threshold.

[0087]

[0077] In one embodiment, one or each of the several optical sensor(s) can comprise a light barrier sensor, in particular an optical micrometer, wherein the optical sensor comprises a transmitter and a receiver arranged facing each other on opposite sides of the first roller.

[0088]

[0078] In one embodiment, the material of the first roller and / or the material of the second roller can comprise steel.

[0089]

[0079] In one embodiment, at least the first roller and / or the second roller can each have corresponding protruding embossing devices, wherein the protruding embossing devices preferably each have a closed shape. The embossing devices can, in particular, be made of silicone or steel. As the medical product embedded between at least two material webs passes through, the embossing devices can press the sealing material into a frame around the medical product. In the snapshot in which the medical product is located in the roller gap, the embossing devices can press the sealing material around the medical product in a circumferential manner.

[0080] According to a further aspect of the invention, a device for sealing a medical product is provided.The device comprises a means for supplying material or sealing material and the medical product, optionally a means for generating and / or providing a cooling fluid, and a roller system as described above.

[0090]

[0081] In one embodiment, the sealing material can comprise an adhesive, wherein the adhesive can be activated by means of the heating device of the roller system. The sealing material can be adhesively attached by the contact pressure in order to seal the medical product in a germ-tight manner.

[0091]

[0082] According to a further aspect of the invention, a method for sealing a medical product using a device as described above is provided. The method comprises the following steps:

[0092] Supplying the sealing material and the medical product,

[0093] Activating the sealing material,

[0094] Detecting the position and / or diameter of the first roller using the optical sensor, wherein the position and / or diameter of the first roller represents the roller spacing, and

[0095] Monitoring the roller gap.

[0096]

[0083] In an embodiment in which the roller system includes the further sensor, the method may further include:

[0097] Determining the position and / or diameter of the second roller, and

[0098] Determining the roller position from a difference between the detected position and / or diameter of the first roller and the detected position of the second roller.

[0099]

[0084] In one embodiment, monitoring the roller position can further include:

[0100] - Comparing the roller position with a predetermined threshold, and

[0101] - Recording an error code in a production log if the roller gap exceeds the predetermined threshold and / or controlling the roller system and / or interrupting the process.

[0102]

[0085] By recording or entering the error code in the production log, the quality of the sealing seam can be continuously monitored, so that it is possible to react to new findings regarding the quality requirements for the sealing seam at a later time.

[0103]

[0086] In one embodiment, monitoring the roller position can further comprise comparing the roller distance with a first predetermined threshold and with a second predetermined threshold, wherein:

[0104] - if the roller gap is greater than the second predetermined threshold, interrupt the process,

[0105] - if the roller gap is greater than the first predetermined threshold and less than or equal to the second predetermined threshold, record the error code in the production log.

[0106]

[0087] In other words, a tolerance range for the quality of the seal can be defined between the first predetermined threshold and the second predetermined threshold.

[0088] In one embodiment, the sealing material can comprise at least two films. The method can further include feeding the medical product, wherein the medical product can be arranged between the at least two films.

[0107]

[0089] Although the roller system has been described above primarily in relation to a sealing application, the roller system can be set up for a variety of other applications, in particular an embossing, cutting, punching and / or material forming application.

[0108] Brief description of the characters

[0109]

[0090] The invention or further embodiments and advantages of the invention will now be explained in more detail with reference to drawings, which only describe embodiments of the invention. Identical components are identified in the drawings by the same reference numerals. Elements drawn with dashed lines are considered optional elements.

[0110]

[0091] The drawings are not to be regarded as being to scale, and individual elements of the drawings may be depicted in an exaggeratedly large or exaggeratedly simplified form.

[0111] Fig. 1 shows a front view of an embodiment of a roller system according to one aspect of the invention.

[0112] Fig. 2 shows a perspective view of an embodiment of the optical sensor for monitoring the roller gap according to one aspect of the invention.

[0113] Fig. 3 shows a perspective view of a further embodiment of the optical sensor for monitoring the roller gap according to one aspect of the invention.

[0114] Figs. 4a and 4b show perspective views of a further embodiment of the optical sensor for monitoring the roller gap according to one aspect of the invention.

[0115] Figs. 5A and 5B show perspective views of the roller system from Fig. 1.

[0116] Fig. 6 schematically shows an embodiment of a roller system according to one aspect of the invention.

[0117] Fig. 7 schematically shows another embodiment of a device according to one aspect of the invention.

[0118] Fig. 8 shows a flowchart for a first embodiment of a method according to one aspect of the invention.

[0119] Fig. 9 shows a flowchart for a second embodiment of a method according to one aspect of the invention.

[0120] Detailed description of the characters

[0121]

[0092] Fig. 1 shows a front view of an embodiment of a roller system 1 according to one aspect of the invention.

[0122]

[0093] The roller system 1 shown in Fig. 1 is designed to seal a medical product, in particular a flat medical product, such as a plaster (not shown).

[0123]

[0094] For this purpose, the roller system 1 comprises a pair of rollers 10; 20, comprising a first roller 10 and a second roller 20, which are arranged at a roller distance 5 from each other. The two rollers 10; 20 can each have a corresponding embossing device 15; 25, which can be positioned on the respective outer surface of the first roller 10 or the second roller 20. The embossing device 15; 25 can have a polygonal, closed shape. The roller distance 5 can be defined as the distance between the outer surfaces of the first roller 10 and the second roller 20 or as the distance between the respective corresponding embossing devices 15; 25 (not shown).

[0124]

[0095] The two rollers 10; 20 are each rotatably mounted on a pivot axis 11; 21. The pivot axis 11 of the first roller 10 can be displaceable relative to the pivot axis 21 of the second roller 20, as indicated in Fig. 1 by the lateral double arrow.

[0125]

[0096] The two rollers 10; 20 can be arranged in a holding device 50. The holding device 50 in Fig. 1 is designed as a closed frame. The holding device 50 allows the rollers to be arranged precisely in the same plane. In other words, the axis of rotation 11 of the first roller 10 can be arranged or aligned parallel to and vertically above the axis of rotation 21 of the second roller 20.

[0126]

[0097] The roller system 1 shown in Fig. 1 comprises a sensor 30, which is designed as an optical sensor. The optical sensor can be arranged on the holding device 50 by means of a carrier or support device 31. In the embodiment shown in Fig. 1, the first roller 10 is arranged vertically above the second roller 20, and the optical sensor is located above the first roller 10. The optical sensor can have a relatively wide measuring range, in particular a considerably wider measuring range than a capacitive sensor. This large measuring range of the optical sensor is advantageous for the continuous acquisition of roller parameters of the first roller 10, whose axis of rotation 11 has a freedom of movement that exceeds the measuring range of more favorable capacitive sensors.

[0127]

[0098] The embodiment of the roller system 1 shown in Fig. 1 can further comprise an additional sensor 40, which may preferably be designed as a capacitive sensor or capacitive measuring system. As shown in Fig. 1, the additional sensor 40 can be arranged directly below the second roller 20. The axis of rotation 21 of the second roller 20 can be fixed, so that only the diameter of the second roller 20 can change by expansion or contraction. In particular, if the material comprising the second roller 20 is steel, expansion of the rollers 10 and 20 due to heating can have a measurable influence on the roller gap, which is ideally less than 100 pm. However, since the thermally induced expansion of the radius of the second roller 20 is within the measuring range of a capacitive sensor, its use as a further sensor 40 for recording roller parameters of the second roller 20 is a viable option.

[0128]

[0099] The maximum measuring distance of a capacitive sensor is typically 1 mm, so a capacitive sensor, as an additional sensor 40, should not be positioned more than 1 mm from the measuring surface of the second roller 20. Since the first roller 10 can be raised by at least 20 mm or more when stationary, capacitive sensors can only be installed on the second roller 20 and not on the first roller 10. The advantage of capacitive sensors lies in their insensitivity to temperature.

[0129]

[0100] From the recorded roller parameters, in particular from a position of the rollers 10; 20 and / or the diameters of the rollers 10; 20, the roller gap can be derived, as described in more detail in connection with Fig. 8 or Fig. 9.

[0130]

[0101] Fig. 2 shows a perspective view of an embodiment of the optical sensor 30 for monitoring the roll gap according to one aspect of the invention.

[0102] The embodiment of the sensor 30 shown in Fig. 2 can be an optical micrometer comprising a transmitter 33 and a receiver 34. The transmitter 33 and the receiver 34 are positioned opposite each other on a support device 31, by means of which the optical sensor 30 can be arranged on the roll system 1.

[0131]

[0103] The transmitter 33 is configured to emit a vertically extended light curtain (not shown) which is detected by the receiver 34. If the transmitter 33 and receiver 34 are arranged on opposite sides of the first roller 10, and the first roller 10 protrudes more or less into the area between the transmitter 33 and receiver 34 due to displacement or thermal deformation, the intensity of the light curtain registered by the receiver changes accordingly. The receiver can detect not only a change in the overall intensity of the light curtain, but can also detect, with a resolution in the range of a few nanometers, how far an object protrudes into the light curtain. This allows the position and / or diameter of the first roller 10 to be detected with sufficient accuracy to detect deviations from an ideal roller gap online, i.e., immediately.

[0132]

[0104] The higher the light curtain generated by the transmitter 33, the greater the possible measuring range of the optical sensor 30. In one embodiment, the optical sensor 30 can have a measuring range of 40 mm.

[0133]

[0105] Fig. 3 shows a perspective view of a further embodiment of the optical sensor 30 for monitoring the roller gap according to an aspect of the invention.

[0134]

[0106] The sensor 30 shown in Fig. 3 comprises two optical micrometers, like the one in Fig. 2, which are aligned parallel to each other by a connecting element of the support device 31. By means of the connecting angled element of the support device 31, the optical sensor 30 can be arranged on the holding device 50, as shown in Fig. 1. In this way, the optical sensor 30 can be positioned above the first roller 10.

[0135]

[0107] Fig. 3 also shows the connections of the receivers 34 of the optical sensor 30, through which the respective receiver 34 can be brought into communication with a processing unit of the roller system 1 (see Fig. 6 and Fig. 7).

[0136]

[0108] The support device 31 of the sensor 30 from Fig. 3 has a cavity 32, which can be configured as a bore. The cavity 32 can extend longitudinally along the support device 31. In one embodiment, a cooling fluid, e.g., compressed air, can be passed through the cavity 32 to temperature-control the sensor 30 during operation within its permissible operating temperature range.

[0137]

[0109] Figs. 4a and 4b show perspective views of a further embodiment of the sensor 30 for monitoring the roller gap according to an aspect of the invention.

[0138] [HO] In Figs. 4A and 4B, a section is shown through the support device 31 of the sensor 30, which shows that the cavity 32 can extend longitudinally through the support device 31.

[0139]

[0111] The optical sensor 30 shown in Fig. 4A and Fig. 4B also comprises two optical micrometers, as in Fig. 2 and Fig. 3, which are aligned parallel to each other by a connecting angled element of the support device 31. The optical sensor 30 can be arranged on the holding device 50, as shown in Fig. 1, by means of the connecting angled element of the support 31. In this way, the optical sensor 30 can be positioned above the first roller 10.

[0112] The cavity 32 allows the sensor 30 to be cooled locally, thereby reducing the required cooling capacity without affecting the process temperature for embossing or sealing the medical product.

[0140]

[0113] Fig. 5 A and 5B show perspective views of the roller system 1 from Fig. 1.

[0141]

[0114] From the further perspectives of the embodiment of the roller system from Fig. 1, the exemplary arrangement of the sensor 30 can be seen. The sensor 30, for example an optical sensor as shown in one of Figs. 3 or 4A or 4B, can be positioned on the holding device 50 above the first roller 10 by means of the connecting angle element of the support device 31.

[0142]

[0115] In one embodiment, the first roller 10, more precisely a rounding of the roller shell of the first roller 10, can already project into the area between transmitter 33 and receiver 34 of the optical sensor 30 in a position from which the ideal roller gap of 80 pm ± 5 pm required for operation results.

[0143]

[0116] From the perspectives of the roller system shown in Fig. 5A and Fig. 5B, it can be seen that the axis of rotation 11 of the first roller 10 can be continuously displaced vertically in the holding device 50. When the rollers 10; 20 are stationary, the first roller 10 can be raised to prevent local overheating in the roller gap.

[0144]

[0117] Fig. 6 schematically shows an embodiment of a roller system 1 according to one aspect of the invention.

[0145]

[0118] The roller system 1 shown in Fig. 6 can comprise the holding device 50, a fluid connection 70, a heating device 60 and a processing unit 80. The fluid connection 70 can be coupled to the holding device 50, in particular for cooling the optical sensor 30, which can also be arranged on the holding device, as shown in Fig. 1 or Fig. 5A and Fig. 5B.

[0146]

[0119] The heating device 60 can comprise at least one heating element arranged in the first roller 10 and / or the second roller 20 and configured to heat the first roller 10 and / or the second roller 20 for operation.

[0147]

[0120] The processing unit 80 can be coupled with the optical sensor 30 and, optionally, the additional sensor 40 to receive sensor data including the roll parameters and to determine and monitor the roll gap based on the sensor data. The method for determining and monitoring the roll gap is described in more detail with reference to Figures 8 and 9.

[0148]

[0121] Fig. 7 schematically shows an embodiment of a device 100 according to one aspect of the invention.

[0149]

[0122] The device 1 shown in Fig. 7 comprises the roller system 1 according to the embodiment shown in Fig. 6, a means 120 for supplying the sealing material and a means 110 for providing or generating a cooling fluid flow.

[0150]

[0123] The means 120 for supplying the sealing material can, for example, be designed as described in WO 2022 / 078636 Al.

[0151]

[0124] The means 110 can be a compressed air connection or a compressor for generating compressed air. The temperature of the compressed air can be in the range of 15°C to 30°C, preferably 15°C to 20°C, and even more preferably at approximately 18°C.

[0125] Fig. 8 shows a flowchart for a first embodiment of a method according to one aspect of the invention.

[0152]

[0126] In a first step S1, the method comprises feeding the sealing material and the medical product. In a second step S1, the method comprises activating the sealing material. In a third step S3, the method comprises detecting the position and / or diameter of the first roller 10 using the optical sensor 30. The position and / or diameter of the first roller 10 represents the roller spacing 5. For example, the roller spacing 5 can be read from a lookup table based on the detected position and / or diameter.

[0153]

[0127] In an optional step S3', the method can include detecting the position and / or diameter of the second roller 20 to increase the measurement accuracy of the roller distance 5.

[0154]

[0128] In a fourth step S4, the method includes monitoring the roller status 5.

[0155]

[0129] Monitoring the roller distance 5 can include controlling the roller distance 5, an emergency shutdown of the roller system 1 and / or recording a process parameter in a corresponding log.

[0156]

[0130] In an optional fifth step S5, the method can include determining the roller position 5 from a difference between the detected position and / or diameter of the first roller 10 and the detected position and / or diameter of the second roller 20.

[0157]

[0131] Fig. 9 shows a flowchart for a second embodiment of a method according to one aspect of the invention.

[0158]

[0132] Regarding steps SI, S2, S3, S3', S4 and S5, reference is made to the description of Fig. 8. The embodiment of the method according to Fig. 9 further comprises continuous cooling S10 of the sensor 30 during the execution of the subsequent steps.

[0159]

[0133] In summary, the roller system according to the invention has the advantage that it makes the roller gap, which is an essential parameter for the quality of the sealing seam, monitorable online. In addition, the local cooling of a sensor for detecting the position and / or diameter of the first roller or for monitoring the roller distance has the advantage that more complex sensors can be used which have a larger measuring range and / or a better resolution for detecting the roller gap.

[0160] Reference sign list ste 31 Carrying device

[0161] I Roller system 32 cavity

[0162] 5 reel spacing 33 transmitters

[0163] 10 first roller 34 receivers

[0164] II Rotation axis of the first roller 40 additional sensor

[0165] 15 Embossing device of the first roller 50 Holding device

[0166] 20 second roller 60 heating device

[0167] 21 Rotation axis of the second roller 70 Fluid connection

[0168] 25 Embossing device of the second roller 80 Processing unit

[0169] 30 Sensor 100 Device 110 Means for generating and / or providing a cooling fluid

[0170] 120 means for supplying sealing material and the medical product

Claims

Patent claims 1. Roller system for sealing a medical product, in particular a flat medical product, wherein the roller system comprises: a first roller (10) and a second roller (20) rotatably mounted at a variable roller distance (5) from each other and configured to generate a contact pressure for sealing the medical product, one or more sensors (30) for detecting the position and / or diameter of the first roller (10) or for monitoring the roller position (5), a heating device (60) for heating the roller system, and a fluid connection (70) for providing a cooling fluid for cooling one sensor (30) or each sensor (30) of the multiple sensors.

2. Roller system according to claim 1, wherein one or each of the multiple sensor(s) is designed as an optical sensor, preferably as a light barrier sensor, in particular as an optical micrometer, wherein one or each of the multiple sensor(s) (30) comprises a transmitter (33) and a receiver (34) arranged facing each other on opposite sides of the first roller (10).

3. Roller system according to one of the preceding claims, wherein the cooling fluid comprises an airflow, wherein the airflow has a temperature in the range of 10°C to 30°C.

4. Roller system according to one of the preceding claims, further comprising a hollow structure through which the cooling fluid can be guided.

5. Roller system according to claim 4, further comprising a holding device (50) in which the first roller (10) and the second roller (20) are rotatably mounted, and wherein one or each of the multiple sensor(s) (30) is arranged on the holding device (50) by means of a support device (31), wherein the hollow structure comprises a cooling channel (32) in the support device (31).

6. Roller system according to claim 5, wherein the cooling channel (32) in the support device (31) extends along the direction of the greatest extent of the support device (31), preferably along the longitudinal direction of the support device (31).

7. Roller system according to one of the preceding claims, further comprising a pressure reducer arranged downstream of the optical sensor (30) in the cooling fluid stream.

8. Roller system according to the preceding claim, further comprising a temperature sensor for monitoring the temperature of one or each sensor (30), and a processing unit (80) which is set up to control a flow rate of the cooling fluid based on the temperature of the sensor or sensors (30).

9. Roller system according to one of the preceding claims, further comprising one or more additional sensor(s) (40), preferably a capacitive sensor, which is configured to detect the position and / or diameter of the second roller.

10. Device (100) for germ-tight sealing of a medical product, the device comprising: a means (120) for supplying sealing material and the medical product, a means (110) for generating and / or providing a cooling fluid, and a roller system (1) according to one of the preceding claims.

11. Device (120) according to claim 10, wherein the sealing material comprises an adhesive, wherein the adhesive can be activated by means of the heating device (60) of the roller system (1), wherein the sealing material can be adhesively attached by means of the contact pressure in order to seal the medical product germ-tight.

12. Method for germ-tight sealing of a medical product using a device (100) according to one of claims 10 or 11, the method comprising the steps: Feeding (Sl) the sealing material and the medical product, Activating (S2) the sealing material, Cooling (S10) of one or each sensor (30), Detection (S3) of the position and / or diameter of the first roller (10) by means of one or each sensor (30), wherein the position and / or diameter of the first roller (10) represents the roller spacing (5), and Monitoring (S4) of the roller position (5).

13. The method of claim 12, wherein the cooling (S10) of one or each sensor (30) further comprises: Inflow of the cooling fluid into the roller system (1), and Reducing the pressure of the cooling fluid downstream before cooling one or each sensor (30).

14. Method according to claim 12 or 13, wherein the roller system (1) is configured according to claim 8 and further comprises cooling (S10) of one or each sensor (30): - Determining the temperature of the sensor (30), and - Controlling the flow rate of the cooling fluid based on the temperature of the sensor (30).

15. Method according to any one of claims 12 to 14, wherein the roller system is configured according to claim 3 and the method further comprises: Capture (S3) 1) the position and / or diameter of the second roller (20), and determining (S5) the roller position (5) from a difference between the detected position and / or diameter of the first roller (10) and the detected position and / or diameter of the second roller (20).

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