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WO2023285248A1 - Sac constitué d'un film souple de réception d'un liquide, système comprenant ce sac et unité d'analyse - Google Patents

Sac constitué d'un film souple de réception d'un liquide, système comprenant ce sac et unité d'analyse Download PDF

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Publication number
WO2023285248A1
WO2023285248A1 PCT/EP2022/068776 EP2022068776W WO2023285248A1 WO 2023285248 A1 WO2023285248 A1 WO 2023285248A1 EP 2022068776 W EP2022068776 W EP 2022068776W WO 2023285248 A1 WO2023285248 A1 WO 2023285248A1
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WO
WIPO (PCT)
Prior art keywords
bag
sensor
substance
measurement
measurement signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2022/068776
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German (de)
English (en)
Inventor
Antoni Picard
David SCHÖNFISCH
Göddel MICHAEL
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HOCHSCHULE KAISERSLAUTERN
Original Assignee
HOCHSCHULE KAISERSLAUTERN
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by HOCHSCHULE KAISERSLAUTERN filed Critical HOCHSCHULE KAISERSLAUTERN
Priority to DE112022003590.0T priority Critical patent/DE112022003590A5/de
Publication of WO2023285248A1 publication Critical patent/WO2023285248A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/24—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid
    • G01F23/246—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid thermal devices
    • G01F23/247—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid thermal devices for discrete levels

Definitions

  • Bag made from a flexible foil for absorbing a liquid and system with bag and evaluation unit
  • the present invention relates to a bag made of a flexible film for holding a substance containing a liquid and a system for determining the fill level of a substance containing a liquid, the system comprising a bag with a sensor and an evaluation unit for detecting a measurement signal from the sensor.
  • Some bags are known in the state of the art that enable a filling level measurement. Different measuring systems are used here, starting with pressure measurement through capacitive measurement or resistance measurements. There are also gravimetric measurements or a combination of different measuring principles, for example in combination with absolute temperature measurements.
  • the infusion container of CN 1 695 586A has a sensor that is based on temperature measurement and takes into account an increase in temperature to determine the filling level.
  • WO2000037129A1 proposes a temperature measurement in a kind of "equilibrium state", while US20170160754A1 describes a static temperature measurement.
  • the measuring medium With the usual automated capacitive or resistive measurements, the measuring medium must be dielectric or electrically conductive.
  • the measuring electrodes are usually in electrical contact with the measuring medium or the environment.
  • these methods are disadvantageous in that the measurement can be influenced by capacitive and electrical parasitic couplings, for example if the bag is touched or if the liquid comes into electrical contact with the human body. Variations and changes in the measurement medium, i.e. in the stored substance, also lead to changes in composition and affect the measurement result. In the case of urostoma bags in particular, the measurement is influenced by a flowing liquid.
  • the measuring principle should be applicable to different types of bags, starting with drinking bags that are integrated in a backpack or in a box, for example, infusion bags to recognize when they need to be changed or refilled, catheter bags in hospitals or urostomy bags in everyday life to allow the wearer easy verification.
  • the present problem is solved by a bag with the features of claim 1 and by a system with the features of claim 14.
  • the present invention relates to a flexible film pouch for containing a substance containing a liquid and having an inlet for delivering the substance.
  • the substance has an effusivity or a heat penetration coefficient that differs from the heat penetration coefficient or the effusivity of air.
  • the bag includes a sensor for determining the fill level of the substance in the bag, where the sensor is a temperature sensor which is designed and set up to infer the effusivity of the substance.
  • the sensor has further on Heating element that emits a heat pulse and is placed on a carrier substrate.
  • the senor is designed and set up to emit a transient heat pulse and to generate a measurement signal, by means of which the effusivity of the substance can be directly concluded and the quality of the measurement signal can be determined.
  • the bag's sensor is therefore designed and set up to create the possibility of assessing and validating the quality of the measurement signal and thus allowing conclusions to be drawn about the quality of the measurement.
  • the invention relates to a system for determining the fill level of a substance containing liquid, the system comprising a bag with a sensor, preferably a bag described above, and an evaluation unit for detecting a measurement signal of the sensor of the bag.
  • the bag is formed of a flexible film for containing the liquid-containing substance and has an inlet for supplying the substance, the effusivity of which is different from the effusivity of air.
  • the sensor of the bag is a sensor, preferably a temperature sensor, which is designed to infer the effusivity of the substance, in other words to determine an equivalent of the effusivity or the heat penetration coefficient.
  • the characteristic variable required for this can preferably be a voltage, a current, a resistance or a temperature.
  • the sensor is designed and set up to emit a transient heat pulse and to generate a measurement signal, by means of which the effusivity of the substance can be directly concluded and the quality of the measurement signal can be determined.
  • the sensor is also designed and set up to determine and assess the quality of the measurement. The assessment can be made in the evaluation unit take place. In this way, the quality of the measurement signal can be assessed and validated, and it can be determined whether the substance in the bag is standing by the sensor or is flowing past it.
  • the sensor includes a heating element that emits a transient heat pulse and is applied to a carrier substrate. It has a connection to the evaluation unit in order to emit a measurement signal to the evaluation unit and to supply energy to the heating element.
  • the evaluation unit is set up and designed to emit energy in the form of a pulse to the heating element and to receive a measurement signal from the sensor and to detect a change in the fill level in the bag by evaluating the measurement signal. Due to the use of a transient heat pulse, it is possible - in contrast to the prior art, which provides for a temperature measurement in a kind of "equilibrium state" - to determine a convection flow of the substance contained in the bag. It can therefore be determined whether the substance is merely flowing past the sensor or whether a fill level is actually being measured, i.e. there is a sufficiently static measuring situation.
  • a bag made of a flexible film which has a sensor of simple construction.
  • the sensor is based on a measuring principle for thermally measuring the heat penetration coefficient of the sensor's surroundings.
  • the sensor comprises a heating element which emits a heating pulse and the properties of which are then measured. For example, the resistance of the heating element can be determined and so that the temperature in the area around the sensor can be deduced.
  • the measuring principle on which the invention is based presupposes that the substance to be measured or the medium has an effusivity which is different from the effusivity of air.
  • the measuring principle is based on not measuring any temperature increase, but rather determining the effusivity from the measured values obtained.
  • a straight line fit is preferably generated, which is more preferably placed as a straight line over the measured values that are currently plotted over the square root.
  • the straight line fit can be obtained from a linear regression, for example.
  • the quality of the regression and the quality of the measured values or the measurement can be determined and assessed from the linear regression (as additional information).
  • the accuracy of the measurement can be determined by the quality of the linear regression (R 2 value) and by a quantitative analysis of the effusi vity. The determination can be made with or without the influence of convection.
  • the options for assessing and using the bag as well as the robustness of the measurements are significantly increased.
  • the validity of the measurement results can be determined directly, for example from the R 2 value of the linear regression and the consideration of a temperature increase over the root of time.
  • the influence of convection can be recognized and assessed. In this way it can be recognized if a substance or a liquid is only moving and the measurement does not show the fill level in the bag, but only a substance or medium or liquid flowing past the sensor or in motion is detected by the sensor.
  • the bag Due to this simple structure of the measuring principle, the bag is very cheap overall, so that it can be manufactured at low cost. Since the bag only includes the sensor and an inlet for feeding in the substance to be measured and no expensive evaluation electronics or evaluation unit, it can also be produced easily and in large quantities will. No technically demanding know-how is required for its production.
  • the pouch can be disposable.
  • the energy requirement that is necessary for determining the fill level in the bag is also very small. Due to the low voltages and currents, the operation of the bag is completely safe and it can therefore be worn on the body without having to take any special precautions. In addition, due to the low energy requirement, long-term supply is possible and only requires a small and light energy supply, which further increases the carrying comfort of the bag. For example, rechargeable batteries, roughly the size of button cells, or one or two button cell batteries are sufficient to operate the sensor for several weeks.
  • the bag Since the bag only has to have one connection, it is very easy to handle, so that the bag is more widely accepted by users. This is especially true when the bag is used in the medical Be rich for absorbing body fluids or other bodily excrement.
  • a planar heating element is attached to the surface of a material - e.g. a bag filled with liquid - and this is heated using an electric current, the energy supplied leads to heating of the heating element and heating of the material in the immediate vicinity of the heating element a removal of heat according to the material-specific heat conduction coefficient as well as a removal of heat through movement of the material (convection). If the system is designed appropriately - eg with a heating element with a very low thermal mass - the energy required to heat the heating element is low.
  • the heat energy flows into the adjacent material and causes a) heating of the material there - determined by the heat capacity c v b) removal of heat by conduction - determined by the coefficient of thermal conductivity lc) removal of heat by natural or forced convection, ie by material transport. If the material does not move, ie the influence of convection can be neglected, the loss of heat energy from the heating element is essentially determined by the combination of material heating and heat conduction. Considered together, this effect is described using the thermal effusivity e.
  • the thermal effusivity e of a substance is a function of its thermal conductivity l and its volumetric heat capacity c v .
  • the temperature change (Dq) of the heating element is a linear function over the root of the heating period t.
  • the increase in the temperature of the heating element is inversely proportional to the effusivity e of the adjacent material.
  • a heat pulse is fed to the material to be examined via a very thin planar heating meander (thickness of approx. 1 ⁇ m) and the change in the temperature of the heating element is measured.
  • a very thin planar heating meander thickness of approx. 1 ⁇ m
  • the theoretically strictly linear Vt dependency of the temperature profile of the heating element is therefore not observed at the beginning of the heating phase, ie immediately after the start of heating. But after a very short time, when the heat flow (heat pulse) reaches the material to be examined, the linear Vt dependency of the temperature profile becomes clearly recognizable.
  • the measured values for the temperature curve A8(Vt) can then be fitted within a specified interval, for example with the aid of a linear regression (least square).
  • the measured value obtained in this way can be the slope of this fitted function.
  • the slope of the function is inversely proportional to the effusivity of the substance (substance) under investigation, as long as the effusivity alone determines the heat loss at the heating element.
  • the quality of this evaluation is determined, for example, using the R 2 value of the linear regression.
  • R 2 1 (ideal case): All measuring points lie exactly on the fitted function.
  • R 2 ⁇ 1 Scatter of the measured values around the fitted function.
  • the determined R 2 value is close to 1 (0.98 - 0.99).
  • the measurement curve A (Vt) for example, no longer corresponds to the ideal linear Vt curve. Accordingly, the quality of the straight line fit will decrease significantly, ie the R 2 value will be significantly lower.
  • the measuring arrangement therefore not only allows the effusivity - and thus the fill level - to be determined, but also, based on the R 2 value, to clarify whether, in addition to the effusivity, convection has also contributed to the cooling of the heating element.
  • This makes it possible to distinguish whether the material (substance) or the liquid is still (virtually immobile) in front of the heating element or whether the liquid (substance) is in motion. It is therefore important not only to observe “any temperature increase", but to analyze and interpret the course of the temperature increase during a transient heating pulse. In this way, for example, the validity of the measurement can be assessed directly by analyzing the course of the curve. For a reliable level measurement, the substance (liquid) should be essentially still. A good R/Vert indicates this condition.
  • the foil of the bag can be hidden (measuring values are only considered after e.g. 0.1 to 0.2 seconds) or the body on which the bag is lying (measuring values are not considered after e.g. 1.5 seconds).
  • the duration of the heating pulse or the selection of which time interval is used for the evaluation can thus be set up to which distance from the heating meander (sensor or heating element) the environment has an influence on the measurement signal.
  • the sensor has such a low thermal mass that a transient heat pulse with a pulse length of at most 2 seconds can be emitted.
  • the sensor therefore has such a small mass that it is also suitable for a transient measurement and not only for static measurements in the steady state or equilibrium state, which would correspond to a thermal conductivity measurement. It is therefore important that the sensor has no inertia, or one that is negligible in practice, which can ultimately be determined by its mass.
  • the senor has a thickness of at most 20 ⁇ m, preferably at most 10 ⁇ m, particularly preferably at most 8 ⁇ m.
  • the small thickness of the sensor is preferred so that the low mass (thermally relevant mass) or inertia can be achieved.
  • the thickness of the preferably planar sensor is significantly less than the thickness of the bag or the thickness of the film of the bag.
  • the thickness of the sensor can be less than one fifth of the thickness of the bag, preferably less than one tenth of the thickness of the bag.
  • the property of the targeted delivery of a transient heat pulse (preferably with a pulse length of less than 1 second) can only be realized reliably and guaranteed or robustly with a light and thin sensor.
  • the sensor is preferably constructed in such a way that it has a sensor area of at most 50 mm 2 , more preferably at most 30 mm 2 and particularly preferably at most 25 mm 2 .
  • the sensor can be constructed essentially of polymide, such that the sensor has a density of about 1.43 g/cm 3 .
  • the thin trace of the heating element is approx. 1 ⁇ m thick and surrounded by the polymide material. The heating element can be neglected due to its low mass.
  • the sensor also preferably has a mass of at most 2 mg, more preferably at most 1 mg, very preferably at most 0.5 mg. in the Sensors whose mass preferably has a maximum of 0.37 mg have proven themselves in practical use.
  • the senor has a very low specific heat capacity, which is preferably at most 5 kJ/(K * kg), very preferably at most 3 kJ/(K * kg), particularly preferably at most 2 kJ/(K * kg ) is.
  • the sensor can have a specific thermal capacity of about 1.13 kJ/(K * kg).
  • a mass of 0.3575 mg results for a preferred sensor with a sensor area of 25 mm 2 , a thickness of 10 ⁇ m and a density of 1.43 g/cm 3 .
  • a specific heat capacity of about 1.13 kJ/(K * kg) a heat capacity of 0.404 mJ/K results for such a sensor.
  • Such a sensor is preferably particularly suitable for pulsed operation.
  • the senor is only formed by the heating element.
  • the heating element is used to generate the heat pulse and, on the other hand, the change in temperature or the change in resistance of the heating element is measured.
  • the heating element is preferably designed as a PTC element (Positive Temperature Coefficient Element) and thus represents a temperature-dependent resistance. The temperature can easily be inferred from the resistance measurement.
  • the heating element is applied to a carrier substrate.
  • This can be applied or glued to the bag.
  • the carrier substrate for receiving the heating element is a film that is glued onto the bag.
  • the carrier substrate is very preferably the film of the bag itself.
  • the heating element is advantageously applied to the carrier substrate using thin-film technology.
  • the heating element can be printed onto the carrier substrate.
  • the heating element is particularly preferably printed directly onto the film of the bag. For example this can be done inexpensively in large quantities using conductive ink or paste in modern printing processes. Such processes include roll-to-roll processes.
  • the senor is preferably an integral part of the bag and enables simple and inexpensive production.
  • the printing of the sensor or the heating element can preferably be carried out on large substrates.
  • the sensors are printed onto large webs of film from which the bags are made using conventional methods such as appropriate cutting and welding, e.g. plastic welding or other methods. The sensors no longer have to be glued onto the bags afterwards.
  • the bag only includes the sensors, ie only the heating element in the present preferred case, and a connection for a line to the evaluation unit, for example, it is completely unproblematic from the point of view of waste recycling.
  • Plastic foils with a thin sensor layer that is glued or printed onto the foil can be disposed of without any problems. Since no other components are arranged on the bag or integrated into it, the bag can be designed as a disposable product. As soon as a predetermined or desired fill level is reached, the bag can be disposed of.
  • the heating element is supplied with an energy pulse, for example a current pulse, and then emits a heat pulse.
  • a transient heat pulse is preferably emitted, the pulse length being at most 1.5 seconds in duration.
  • the pulse duration is therefore preferably at most 1 s, preferably at most 500 ms. are more preferred Pulse durations of at most 200 ms or only 100 ms if the substance to be measured is arranged directly on the sensor or on the heating element.
  • the pulse length determines the depth of penetration into the material and thus the location at which a material or substance (e.g. in a bag) can be evaluated and measured.
  • a period of time at the beginning of the measured values is therefore ignored when evaluating the measurement.
  • the measured values are not taken into account because these values are only a measure of the effusivity of the bag film and do not allow any statement to be made about the substance in the bag.
  • the interval limit is typically a few milliseconds to a few tens of milliseconds.
  • the sensor Since the sensor also enables measurement over a certain distance, the sensor is arranged on the outside of the bag in a preferred embodiment. This has the advantage that the sensors or the heating element do not have to be in direct contact with the medium or the substance. In this case, the connections for the heating element are also arranged on the outside of the bag, without having to implement a passage through the film of the bag. Furthermore, the sensors are not subject to any wear. They also do not have to be made from biocompatible and therefore expensive materials such as gold, silver or platinum. Rather, almost any resistive metal layer is suitable.
  • the senor is covered by a cover in order to protect it against mechanical stress, in particular when it is arranged on the outside of the bag.
  • a cover film is particularly preferably used for this purpose, which is thin and light and therefore contributes little to the weight and dimensions of the bag.
  • the carrier substrate could be the cover.
  • the cover could be designed such that the heating element is generated on one side of the carrier material and the back of the carrier material represents protective cover. The side with the heating element could be glued directly onto the bag.
  • the thickness of the bag used is preferably less than 1 mm, preferably less than 500 gm, very preferably at most 150 gm.
  • a film thickness of at most 100 gm has been shown to be sufficient to form a tear-resistant and stable bag. Bags with this layer thickness have the advantage that a robust and reliable measurement from the outside is possible.
  • the effusivity is defined as the square root of the product of the thermal conductivity and the heat capacity and the density of the material. Since for simple embodiments of the bag it only needs to be recognized that the medium to be measured has changed at the location of the sensor, a qualitative measurement is sufficient. In particular, it only needs to be recognized that instead of air, the substance to be recognized is at the measurement location. The exact density of the substance does not have to be known.
  • a curve fit is generated using the measured values over time to determine the quality of the measurement.
  • a straight line fit is preferably generated for the measured values plotted over the root of the time.
  • the quality of the linear regression of the straight line fit can preferably be used as a measure of the quality of the measurement.
  • the bag provides that the sensor is designed and set up to make a distinction as to whether the substance in the bag is standing on the sensor or is flowing past the sensor. The distinction can be made because the convection that occurs can be taken into account in the measurement using the sensor and the system.
  • the bag comprises a plurality of sensors in order to determine the level or degree of filling of the bag as precisely as possible. These sensors are particularly preferably arranged at different heights along one side of the bag, so that different fill levels of the substance in the bag can be detected. It is particularly preferred that not only two but at least three, very preferably at least four, sensors are provided. Depending on the application, the person skilled in the art will weigh up the desired accuracy of determining the filling level and the measuring effort or costs of the bag using multiple sensors.
  • the second sensor is arranged in such a way that it detects twice the fill level of the first sensor.
  • the third sensor is arranged in such a way that it detects three times the fill level of the first sensor. This corresponds to a linear arrangement of the sensors in order to linearly record a fill level.
  • the sensors can also be arranged at predetermined intervals, for example a first sensor relatively close to the lower end of the bag, in order to detect when the bag is not full. This sensor can perform a kind of control measurement. Further sensors can be arranged in the upper area in order to determine a degree of filling of, for example, more than 70%, more than 80% and more than 90% of the bag as reliably and precisely as possible.
  • a differentiated warning can be given before the bag is completely full.
  • the bag is used as a urostomy bag to collect urine, it can be useful to detect that the bag is already 50% full.
  • the sensor is then to be arranged at the appropriate point. Further filling levels to be detected can be provided, for example, at 75, 85 and 95% of the total filling level of the bag.
  • one or more sensors are arranged on opposite sides of the bag, so that by analyzing the different filling levels on different bag sides, the filling quantity can also be determined when the bag is not in a vertical position, for example by averaging, can be determined.
  • layers that are unsuitable for measuring the fill level such as horizontally lying bags, can be separated out.
  • this can contribute to making the measuring result for the filling level more valid.
  • the bag is preferably part of a system for determining the level of a substance containing liquid.
  • the system includes an evaluation unit for detecting a measurement signal from the sensor.
  • the evaluation unit preferably includes a preferably exchangeable or chargeable energy source. Since preferably only a transient measurement is carried out at predetermined measurement intervals, for example at intervals of several 10 s or several minutes, and small energies are possible for the emission of the heat pulse, the demand on the energy source is also low. Small energies are sufficient, so that small rechargeable batteries or batteries designed in the size of a button cell can be used. These are light and cheap.
  • the evaluation unit can not only hit the heating element with a heating current so that a desired heat pulse is emitted. She also does the measurement. A current, a voltage, a resistance or a change in these variables can preferably be detected and used as a measurement signal.
  • the evaluation unit is connected to the sensor of the bag via the sensor connection.
  • the connection can be made for example via a cable or other electrical contacts. It is conceivable that the evaluation unit is integrated in a clip or clamp that is clamped to the bag. In this way, the system is easy to handle for the user.
  • the contact between the sensor and the evaluation unit can be made possible by clipping at a predetermined location, for example by a predetermined form-fitting receptacle for the evaluation unit will. The user then does not have to use a plug connection. Alternatively, a plug connection can be provided.
  • the evaluation unit includes a communication interface for wireless communication with a display device.
  • a communication interface for wireless communication with a display device.
  • an electronic, external device e.g. a smartphone, a wearable, a fitness tracker or a watch
  • the wireless communication could take place via Bluetooth, for example.
  • This has the advantage that the user can read how full the bag is without having to reach for the bag, which is usually worn under clothing. In this way, it is possible for the wearer to monitor the fill level of the bag in a way that is comfortable and very discreet.
  • the pouch and/or system are thus particularly useful in wearable, body-hugging applications.
  • the bag can be designed as a disposable product and for single use.
  • the evaluation unit can be used several times.
  • the evaluation unit can include an alarm function to inform a user about the filling level in the bag or to warn them when a specified filling level is reached.
  • the information or warning can be optical, acoustic or haptic, e.g. by vibration.
  • the evaluation unit can also establish a connection to an external device, for example a mobile phone or smartphone or pager or similar, so that distant people can also be alerted via wireless communication, Bluetooth, Wifi or mobile communications.
  • the evaluation unit includes a measurement circuit or an evaluation algorithm that allows a test value to be determined from the measurement signal received from the sensor of the bag in order to check the measurement signal received and test it for plausibility.
  • the algorithm is preferably designed in such a way that error signals or incorrect signals are determined.
  • the system according to the invention preferably uses a curve fit or preferably a straight line fit for checking the quality of the measurement, which is carried out using the measured values plotted against the square root of time.
  • the quality of the linear regression of the straight line fit is preferably used as a measure of the quality of the measurement.
  • R 2 value With an R 2 value of around 1, the measurement allows a statement to be made, for example, that the filling level in the bag is being measured (standing or dormant substance). If the R 2 value is well below 1, for example less than 0.2, a substance flowing past is detected.
  • the R 2 value is preferably combined with the slope of the measured values in order to increase the accuracy of the measurement and the validity.
  • a Wheatstone bridge is used to determine a measurement signal, with the measurement value offering an equivalent to the effusivity of a medium located at the location of the sensor. This makes it easy to see whether the substance containing liquid is present at the location of the sensor, or whether it is air or just the film of the bag. In other words, the sensor can detect whether a PRE-DETERFILL level has been reached.
  • the film walls of the bag When the bag is deflated prior to the entry of any substance or liquid, the film walls of the bag will abut against each other. In this case, too, the filling level can be detected. If the bag is completely filled with the liquid and sealed at the beginning, i.e. without air pockets, as is the case with an infusion bag, for example, the two film walls will also compress when they are emptied. Here, too, the sensor only sees the rear wall of the foil bag. This is not a problem for the measuring principle, since the effusivity of the film differs from that of the liquid or a substance containing a liquid.
  • the bag according to the invention can be an infusion bag.
  • the bag can also be a stoma or urostoma bag and is then worn directly (with body contact) or indirectly (e.g. under clothing) on the body.
  • the bag comprises one or more additional sensors, which are preferably arranged on the side of the bag or bag film close to the body, particularly preferably on the outside thereof, in order to detect a leak.
  • the change in the effusivity at the coupling surface to the body can be monitored in order to detect liquid leaks at an early stage before they become a problem for the user.
  • the bag comprises additional sensors, preferably a position sensor or a sensor, in order to detect foaming of liquid in the bag.
  • the measurement signals can be processed in the evaluation unit.
  • the position of the bag can be taken into account when evaluating the measurement signals from the effusivity sensors or temperature sensors, in that the signals from the position sensor are also processed in the evaluation unit.
  • An adapted detection of the filling level can take place.
  • FIG. 1 shows a schematic diagram of a system comprising a bag according to the invention and an evaluation unit;
  • FIG. 2 shows the course of a measurement during a heating period of a heating element of the bag
  • FIG. 3 shows a measurement curve in a time window from FIG. 2 with a changed offset
  • Figures 4a-c show the time course of a sensor signal at three sensors S1 to S3 from Figure 1.
  • Figure 1 shows a system 10 according to the invention comprising a bag 20 according to the invention and an evaluation unit 40.
  • the system 10 optionally additionally comprises an external device 50 to Display, output or store data or information from the evaluation unit 40 .
  • the pouch 20 is formed from a flexible film 22 and includes four sensors 24 on its exterior.
  • the sensors 24 are temperature sensors, each of which includes a heating element 26 .
  • the film 22 serves as a carrier substrate 28 on which the heating elements 26 are applied, preferably printed.
  • the heating elements 26 are covered with another film, which is not visible here, so that there is protection against external influences, such as physical contact.
  • the sensors 24 have a common connection 30, an electrical connection 32 to the connection 30 being formed from each of the sensors 24.
  • FIG. In the example shown here, the heating elements 26 are in the form of PTC elements, so that a resistance measurement can be carried out, for example using a Wheatstone bridge.
  • the bag 20 is a urostomy bag in which urine is collected.
  • An inlet 34 is provided in the upper part of the bag 20, via which a substance, for example urine or other bodily excrement, can be fed into the bag.
  • the inlet 34 can have an adapter or connector in order to be able to connect a catheter, line, hose, tube or the like.
  • the sensors 24 are arranged at different points of the bag 20 in order to measure the fill level of the substance in the bag 20 .
  • the lower sensor 24a indicates a fill level of approximately 10%, while the sensors 24b and 24c detect a fill level of 40% and 70%, respectively.
  • the fourth sensor 24d makes it possible to measure a fill level of approximately 90%, at which point a bag change must take place.
  • the evaluation unit 40 is connected to the bag 20 via a connection line 42 , the (electrical) connection line 42 being in contact with the connection 30 of the bag 20 . It can thus be easily separated from the bag 20 and can thus be used several times.
  • the evaluation unit 40 includes an energy source 44, preferably in the form of a battery or a rechargeable battery, to supply the heating element 26 with energy and to generate a heating pulse.
  • a control unit 46 generates a corresponding control signal for the heating element 26 in order to output the heating or heating pulse.
  • the control unit 46 also includes an evaluation algorithm in order to determine a characteristic measurement variable of the measurement signal received from the sensor 24 . In this way, the effusivity of the substance at the sensor 24 or in the vicinity of the sensor 24 is inferred.
  • the characteristic measured variable or the measured value is preferably proportional to a measured temperature at the location of the sensor 24.
  • a communication unit 48 of the evaluation unit 40 enables communication with external devices.
  • the communication unit 48 can be used to output an alarm signal or a status signal that was generated in the control unit 46 . It is conceivable that when a new level is reached, ie when another sensor 24 detects a level, a status signal is generated and output.
  • An alarm signal can be issued if the third sensor 24c and/or the fourth sensor 24d detects the presence of the substance (e.g. liquid) introduced by detecting a changed effusivity of the medium in the vicinity of the sensor 24c, 24d.
  • the signals can then be sent to the electronic device 50, for example a handheld device, a smart watch or a smartphone.
  • Wireless communication is preferably provided, preferably via Bluetooth or a similar, energy-saving communication such as NFC communication (Nearfield Communication).
  • FIG. 2 shows the course of a characteristic measured value for the temperature or the effusivity of a substance or a medium containing liquid contains.
  • the resistance of the heating element 26 is measured, assuming a corresponding temperature coefficient.
  • the course of the measurement during a heating period of the sensor 24 or heating element 26 is shown.
  • the measurement signal is plotted against the root of the time.
  • the heating element 26 is briefly heated; in the present case, the heating period is 2 s.
  • the change in temperature or in the measured value that is proportional to the temperature is also logged.
  • the measurement signal results from the inverse slope when this measurement value is plotted over the square root of time.
  • the inverse gradient can be determined most simply by means of a simple linear regression.
  • the coefficient of determination R 2 of the linear regression aren can also be used advantageously to erroneous, z. B. caused by flowing liquids to filter out measurements.
  • FIG. 2 shows the temperature-proportional measured value over the square root of the heating time from zero to 2 seconds for three examples.
  • the curve L shows the measured value for a sensor 24 which carries out a measurement in air.
  • the interior of the bag 20 is air and not liquid, such as urine.
  • the curve Ff shows the measured value when the liquid is flowing past the sensor 24, while the curve Fs shows the measured value of the sensor 24 when the liquid is inside the bag 20 at the sensor position and covers the sensor area.
  • the sampling interval for the measured value is less than 5 ms; it is about 3 ms in all three measurements, corresponding to a sample rate of 333 Hz.
  • a measurement in the time window Z should be selected for calculating the measurement signal in accordance with the structure of the sensors 24 .
  • the beginning of the time window should be "late enough" to minimize influences from the sensor 24 and its encapsulation or from the foil 22 of the bag 20 . In this way, the influence of the layer between the sensor 24 and the liquid, ie the film thickness, as measured in this example, is reduced.
  • the measurement in the time window Z is shown in FIG. 3 for the sensor 24 with the three different media (air, standing liquid and flowing liquid), the offset having been changed so that the measurement curves each have a measurement signal of 0 at one second.
  • the corresponding measurement curve becomes more linear. This also makes it easier to detect faulty measurements and errors that can be caused by environmental influences.
  • the duration of the time window Z is also dependent on the film thickness and thus on the layer between the sensor 24 and the liquid, in the present case a urostoma bag.
  • the duration of the optimal time window depends on the sampling interval with which the temperature-proportional measured value is measured.
  • the influence of temperature fluctuations and movements of the liquid in the bag 20 can be reduced by shortening the heating period (preferably a maximum of 3 seconds) and/or by reducing the time window for the measurement (preferably a maximum of 1.5 seconds, very preferably at most 1 second).
  • the inaccuracy of the calculation of the inverse gradient increases, so that a corresponding compromise has to be found for the respective application. This can be optimized for a person skilled in the art through simple tests and trial and error.
  • the measurement signal is the temperature-proportional measured value (e.g. voltage or resistance), which is measured with a sampling interval of ⁇ 3 ms for a measurement duration of approx. 2 s. This can be seen from FIGS.
  • the sensor signal is the inverse gradient calculated from the measured values. It is proportional to the thermal effusivity and is determined approximately every 30 seconds, as shown in Figures 4a to 4c.
  • FIGS. 2 and 3 show the course of the measurement signal during the heating of the heating element 26 and thereby represent a value proportional to the temperature over the square root of the time
  • proportional sensor signal S shown over the period of a measurement of 60 minutes for each sensor. The measurement took place over a period of 1 hour.
  • the liquid flowing through the inlet 34 into a urostoma bag was measured using the three sensors 24a to 24c from FIG.
  • the interval for determining the sensor signal is 30 s.
  • the bag 20 is slowly being filled and after about 10 minutes the lower sensor is partially wetted with liquid. From about 16 minutes there is a jump in the measurement curve, so that the sensor signal, which is proportional to the effusivity, increases from about 20 to 120. The fill level at the location of the first sensor 24a is thus reached.
  • FIG. 4b shows the sensor signal of the filling level at the sensor 24b in order to detect a further filling of the bag 20.
  • the liquid flowing into the bag 20 reaches this sensor 24b after about 23 minutes, which is a slight increase of the sensor signal from about 20 to 30. From about 27 minutes, the measured value also increases to about 120, so that the liquid in the bag now completely covers the location of sensor 24b and the effusivity in the area around sensor 24b has increased accordingly. The filling level has therefore been reached.
  • the third sensor 24c which represents the highest filling level, is in any case partially covered by liquid after about 40 minutes and completely after 45 minutes, which results from the measurement curve, which outputs a measurement signal value of about 120 from 45 minutes. In this way, the filling level or degree of filling of the bag 20 can be reliably detected.
  • a bag 20 was used in which the three sensors 24a, 24b, 24c indicated a filling level of 120 ml, 240 ml and 420 ml.
  • the sensor area was about 25 mm 2 in each case.
  • the sensor signal only reached the value 120 when the entire sensor surface was below the liquid level.
  • the resulting measurement has shown that the sensors 24 work very robustly and reliably and that without direct contact of the sensor 24 with the liquid, reliable information about the fill level of liquid bags, in particular urostoma bags, is possible. This has the advantage that the sensors 24 can be attached to the outside of the bag 20 and do not come into direct contact with the liquid.

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  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Orthopedics, Nursing, And Contraception (AREA)

Abstract

L'invention concerne un système (10) permettant de déterminer le niveau de remplissage d'une substance contenant du liquide dans un sac (20), comprenant le sac (20) comportant un capteur (24) et une unité d'analyse (40) permettant de détecter un signal de mesure du capteur (24). Le capteur du sac est un capteur de température conçu pour entraîner l'écoulement de la substance. Le capteur du sac comprend un élément chauffant (26) émettant une impulsion thermique et s'appliquant à un substrat de soutien (28). Le capteur (24) est conçu pour transmettre une impulsion thermique transitoire et pour générer un signal de mesure permettant l'entraînement direct de l'écoulement de la substance et la détermination de la qualité du signal de mesure. Le capteur (24) présente une connexion à l'unité d'analyse (40) permettant de transmettre un signal de mesure à l'unité d'analyse et de fournir de l'énergie à l'élément chauffant. La substance à mesurer présente un écoulement qui diffère de l'écoulement d'air. L'unité d'analyse est conçue : pour transmettre de l'énergie sous forme d'impulsion à l'élément chauffant et pour recevoir un signal de mesure du capteur ; et pour détecter ainsi un changement du niveau de remplissage dans le sac, par analyse du signal de mesure et par évaluation et validation de la qualité du signal de mesure.
PCT/EP2022/068776 2021-07-16 2022-07-06 Sac constitué d'un film souple de réception d'un liquide, système comprenant ce sac et unité d'analyse Ceased WO2023285248A1 (fr)

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DE112022003590.0T DE112022003590A5 (de) 2021-07-16 2022-07-06 Beutel aus einer flexiblen folie zum aufnehmen einer flüssigkeit und system mit beutel und auswerteeinheit

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DE102021118464.9A DE102021118464A1 (de) 2021-07-16 2021-07-16 Beutel aus einer flexiblen Folie zum Aufnehmen einer Flüssigkeit und System mit Beutel und Auswerteeinheit

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Citations (9)

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US5719332A (en) * 1994-09-28 1998-02-17 Vdo Adolf Schindling Ag Process and system for operating a level sensor
WO2000037129A1 (fr) 1998-12-22 2000-06-29 Alcor Medical Instruments Methode de controle de niveau de liquides et dispositif correspondant
CN1695586A (zh) 2005-06-21 2005-11-16 金仲和 一种输液容器
US20140290357A1 (en) * 2013-03-28 2014-10-02 Exxonmobil Research And Engineering Company System and method for identifying levels or interfaces of media in a vessel
US20170160754A1 (en) 2014-06-12 2017-06-08 Halliburton Energy Services, Inc. Determination of substance presence, identity and/or level in vessels
US20190011306A1 (en) * 2015-10-28 2019-01-10 Hewlett-Packard Development Company, L.P. Liquid level indicating
US20190060582A1 (en) * 2017-08-28 2019-02-28 Jabil Inc. Apparatus, system and method of providing a fluid bag heater
US20190060583A1 (en) * 2017-08-22 2019-02-28 Jabil Circuit, Inc. Apparatus, system and method of providing a conformable heater system
WO2020007803A1 (fr) * 2018-07-03 2020-01-09 Iee International Electronics & Engineering S.A. Système de détection de niveau de liquide

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Publication number Priority date Publication date Assignee Title
DE102005053539B4 (de) 2005-11-08 2010-08-12 Continental Automotive Gmbh Vorrichtung und Verfahren zur Bestimmung eines Füllstandes und einer Temperatur eines Fluids
DE102012007825A1 (de) 2012-04-17 2013-10-17 Gunter Arnold Füllstand-Grenzwertgeber für Flüssigkeitsbehälter

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5719332A (en) * 1994-09-28 1998-02-17 Vdo Adolf Schindling Ag Process and system for operating a level sensor
WO2000037129A1 (fr) 1998-12-22 2000-06-29 Alcor Medical Instruments Methode de controle de niveau de liquides et dispositif correspondant
CN1695586A (zh) 2005-06-21 2005-11-16 金仲和 一种输液容器
CN100367922C (zh) * 2005-06-21 2008-02-13 金仲和 一种输液容器
US20140290357A1 (en) * 2013-03-28 2014-10-02 Exxonmobil Research And Engineering Company System and method for identifying levels or interfaces of media in a vessel
US20170160754A1 (en) 2014-06-12 2017-06-08 Halliburton Energy Services, Inc. Determination of substance presence, identity and/or level in vessels
US20190011306A1 (en) * 2015-10-28 2019-01-10 Hewlett-Packard Development Company, L.P. Liquid level indicating
US20190060583A1 (en) * 2017-08-22 2019-02-28 Jabil Circuit, Inc. Apparatus, system and method of providing a conformable heater system
US20190060582A1 (en) * 2017-08-28 2019-02-28 Jabil Inc. Apparatus, system and method of providing a fluid bag heater
WO2020007803A1 (fr) * 2018-07-03 2020-01-09 Iee International Electronics & Engineering S.A. Système de détection de niveau de liquide

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DE112022003590A5 (de) 2024-05-08

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