Device for weighing a quantity of fluid in an extracorporeal blood treatment machine

Abstract

Device (10) for weighing a quantity of liquid in an extracorporeal blood treatment machine, comprising: a mounting unit (11) configured to attach a container (13) for the quantity of liquid to a frame element (14); a weighing sensor unit (15) with a first measuring channel (16) and a second measuring channel (17), wherein the weighing sensor unit (15) is configured to detect a first weight measurement via the first measuring channel (16) and to detect a second weight measurement via the second measuring channel (17); a control unit (18) configured to determine a weight for the quantity of liquid in the container (13) based on the detected first weight measurement and the detected second weight measurement;wherein the weighing sensor unit (15) is configured to acquire a first initialization weight measurement via the first measuring channel (16) and a second initialization weight measurement via the second measuring channel (17) before each weighing of the liquid quantity in an unloaded state of the weighing sensor unit (15) (S1); wherein the control unit (18) is configured to compare the acquired first initialization weight measurement with a first limit value and to compare the second initialization weight measurement with a second limit value (S2);wherein the control unit (18) is configured: if an amount of the first initialization weight measurement is less than an amount of the first limit value and an amount of the second initialization weight measurement is less than an amount of the second limit value, to set the detected first initialization weight measurement as the offset for the first measurement channel (16) and to set the detected second initialization weight measurement as the offset for the second measurement channel (17) (S3); and if an amount of the first initialization weight measurement is greater than an amount of the first limit value and / or an amount of the second initialization weight measurement is greater than an amount of the second limit value, to output an error message (S4).;

Description

Technical field

[0001] The present disclosure relates to a device for weighing a quantity of liquid in an extracorporeal blood treatment machine, in particular a dialysis machine, a computer-implemented method for operating a device for weighing a liquid, a computer program product, a computer-readable storage medium and a dialysis machine with such a device. Technical background

[0002] Load cells for dialysis machines are a well-established technology and are used in dialysis machines to measure fluid volumes. Maintaining a balance between the fluid volumes withdrawn from and administered to the body is crucial. Failure to achieve this balance precisely can lead to complications for the patient. However, load cells are subject to wear and tear and their properties change over time. Therefore, they must be replaced and / or recalibrated periodically. Due to regulations, this process cannot usually be performed by medical personnel. Instead, specially trained technicians are required. This results in high costs, reduced availability, and potentially less accurate fluid volume measurements during operation, thus posing a health risk to patients.

[0003] A method for correcting an offset is known from DE 10 2020 210 605 A1. A sensor for detecting phases and / or phase transitions during peritoneal dialysis treatments is known from DE 10 2013 016 204 A1.

[0004] In this context, it has now become apparent that there is a further need to provide a device for weighing a quantity of fluid in a dialysis machine. Summary of the present disclosure

[0005] It is therefore an object of the present disclosure to provide a device for weighing a quantity of liquid in an extracorporeal blood treatment machine, in particular a dialysis machine; in particular, it is an object of the present disclosure to provide an efficient and accurate device for weighing a quantity of liquid in an extracorporeal blood treatment machine.

[0006] The object of this disclosure is achieved by a device for weighing a quantity of liquid in an extracorporeal blood treatment machine according to claim 1, as well as by the dependent claims. Advantageous embodiments are the subject of the dependent claims and / or are explained below.

[0007] A first aspect of the present disclosure relates to a device for weighing a quantity of liquid in an extracorporeal blood treatment machine, comprising: a fastening unit configured to attach a container, for example a bag, for the quantity of liquid to a frame element; a weighing sensor unit with a first measuring channel and a second measuring channel, wherein the weighing sensor unit is configured to detect a first weight measurement via the first measuring channel and to detect a second weight measurement via the second measuring channel; a control unit configured to determine a weight for the quantity of liquid in the container based on the detected first weight measurement and the detected second weight measurement, wherein the weighing sensor unit is configuredBefore weighing the quantity of liquid in an unloaded state, the weighing sensor unit is to acquire a first initialization weight measurement via the first measuring channel and a second initialization weight measurement via the second measuring channel (S1); wherein the control unit is configured to compare the acquired first initialization weight measurement with a first limit value and to compare the second initialization weight measurement with a second limit value (S2); wherein the control unit is configured to, if an amount of the first initialization weight measurement is less than an amount of the first limit value and an amount of the second initialization weight measurement is less than an amount of the second limit value,to set the acquired first initialization weight measurement as an offset for the first measurement channel and to set the acquired second initialization weight measurement as an offset for the second measurement channel (S3); and wherein the control unit is configured to issue an error message if an amount of the first initialization weight measurement is greater than an amount of the first limit value and / or an amount of the second initialization weight measurement is greater than an amount of the second limit value (S4).

[0008] The term "extracorporeal blood treatment machine" refers specifically to a device for performing extracorporeal blood treatment. A dialysis machine is one example of an extracorporeal blood treatment machine. Dialysis involves purifying a patient's blood. This purification includes, among other things, the removal of waste products, excess fluid, and toxins from the blood. In this context, the focus is specifically on a dialysis machine used for hemodialysis. Besides hemodialysis, a dialysis machine can also be configured for hemofiltration, hemodiafiltration, ultrafiltration, etc. A dialysis machine includes pumps, sensors, a dialyzer, and containers or bags, such as fluid reservoirs or infusion containers.

[0009] In this context, the term "fastening unit" refers to a structural component designed to secure a container, particularly a bag. The fastening unit may be a cantilever arm with a hook for holding a container. Alternatively, the fastening unit may have an interface for attaching a container, which may include a hook. The fastening unit may be a single piece or comprise multiple parts.

[0010] In this context, the term "container" refers specifically to a hollow body into which a liquid can flow and / or out. The container may have a rigid or flexible wall. It may contain a bag or be designed as a bag. The container may be made of plastic. It may be a liquid container, such as an infusion container or a dialysate container.

[0011] The term "frame element" refers to a structural component designed to accommodate or support a mounting unit. A frame element can be, for example, a stand. The frame element can be part of an extracorporeal blood treatment machine, particularly a dialysis machine or dialysis system.

[0012] The term "weighing sensor unit" in this context refers to a unit with at least two measuring channels for detecting a weight, where, according to the present disclosure, a weight is understood to be a mass. The measuring channel comprises a sensor configured to measure a weight. The sensor may include one or more of the following: strain gauge sensor, capacitive sensor, or piezoelectric sensor. The measuring channel further comprises hardware and software for processing and transmitting the detected measurement value. The first and second measuring channels are independent of each other. The first and second measuring channels may have the same or different structures. Preferably, the first and second measuring channels have different structures.

[0013] The term "limit value" here refers to a predetermined value that must not be exceeded. This limit value can be defined specifically for the first or second measurement channel. The first and second limit values ​​can be the same or different. Preferably, the first and second limit values ​​are different. For example, the first and second limit values ​​can be ±20g. The first and second limit values ​​define a maximum adjustment range for the offset. For example, the offset may not be changed by 24g in any direction during a new adjustment. For example, the offset may be changed by 17g during a new adjustment.

[0014] In this context, the term offset refers to a measured value of a measuring channel of the weighing sensor unit in an unloaded state.

[0015] The control unit can, for example, determine the weight of the liquid in the container by using the first weight reading as the value for the liquid in the container. Alternatively, the control unit can determine the weight of the liquid in the container by using the average of the first and second weight readings as the value for the liquid in the container. The control unit can also be configured to calculate the difference between the first and second weight readings and compare this difference to a working limit. The working limit might be, for example, 10 g. Furthermore, the control unit can be configured to issue an error message (e.g., excessive measurement deviation between the measuring channels) if the difference exceeds the working limit.The control unit can still be set up to output the weight for the amount of liquid in the container if the difference does not exceed the operating limit.

[0016] The disclosure is based on the understanding that a load cell inherently exhibits an offset when weighing a quantity of liquid. This means that even in an unloaded state, one of the load cell's measuring channels displays a measurement. This offset can change due to factors such as wear, changes in environmental conditions, or an incorrect setup of the device used to weigh the liquid (e.g., an incorrect hook or an additional load). This offset is typically compared to a limit value, and if the offset is below the limit value, the measurement is taken using the original, pre-defined offset without recalibration. This original, pre-defined offset originates from a calibration performed at the manufacturing plant or from commissioning by a certified metrology technician. If the limit value is exceeded, an error message is generated.However, this has the disadvantage that, firstly, measurements are inaccurate, and secondly, gradual changes in environmental conditions are overemphasized. The invention proposes to record an initial weight measurement in an unloaded state before each measurement for both the first and second measuring channels, compare this value with a limit value, and, if this initial weight measurement is below the limit value, use it as the new offset. This corresponds to a recalibration, but without the need for a metrologist. If one or both measuring channels exceed the limit, an error message is issued. In this way, the measurement accuracy can be increased, since a more precise offset is used in each case, and the availability of the load cell can be increased, as an error message due to gradual deterioration is avoided by requiring a new calibration.Furthermore, the first and / or second limit values ​​can be set higher by performing the described calibration before each measurement run. This can also have a positive effect on availability.

[0017] According to a preferred embodiment, the error message may include a request to check the device with regard to measurement conditions.

[0018] The error message can be displayed, for example, on a screen on the device. The measurement conditions can include the measurement setup and / or the environmental conditions (e.g., temperature, humidity, sunlight). The error message may contain information and / or questions relating to the measurement setup. Questions might include, for example, whether there is truly no weight attached to the device or whether the device or its hook is freely suspended. The user can then check the measurement conditions accordingly and decide whether the measurement should be repeated or whether a technician should be called in.

[0019] In this way, the availability of the device can be advantageously increased.

[0020] According to a preferred embodiment, after checking the device with regard to the measurement conditions, the device can be set up to repeat steps S1 to S4.

[0021] For example, the device can be configured to receive confirmation of the verification from an employee after the check. This can be done via an interface, such as a control panel, a button, or a human-machine interface (HMI). The device can then repeat steps S1 to S4. If the result is positive, the measurement can then be completed successfully. If the result is negative, a repeat error message with the same content or, if necessary, a notification to call a technician may be displayed. The latter inevitably leads to a temporary shutdown of the device.

[0022] In this way, the overall availability of the device can be increased, as the necessary inspection by a technician with new, complex calibration can be avoided.

[0023] According to a preferred embodiment, the control unit can be further configured to compare a first difference between the first detected initialization weight measurement and a first output initialization weight measurement with a first absolute limit, to compare a second difference between the second detected initialization weight measurement and a second output initialization weight measurement with a second absolute limit if the first difference is less than the first absolute limit and the second difference is less than the second absolute limit, to set the detected first initialization weight measurement as an offset for the first measurement channel and to set the detected second initialization weight measurement as an offset for the second measurement channel, and if the first difference is greater than the first absolute limit and / or the second difference is greater than the second absolute limit,to display an error message.

[0024] The term "initialization weight measurement" refers in this context to a measurement determined during calibration with measuring weights, for example, during the manufacture of the weighing sensor unit or the device. The first initialization weight measurement preferably relates to the first measuring channel. The second initialization weight measurement preferably relates to the second measuring channel.

[0025] In this context, the term "absolute limit" refers to a limit value for deviations from an initial initialization weight measurement. The first absolute limit might be, for example, ±100g. The second absolute limit might also be, for example, ±100g. The two absolute limits can be the same or different.

[0026] The difference between the first initialization weight measurement and the currently recorded initialization weight measurement can advantageously indicate how far the currently recorded initialization weight measurement deviates from the original initial initialization weight measurement. If the first absolute limit is exceeded, it can be assumed that there is a defect in the measuring channel and / or that the measurement conditions are not valid. The same applies analogously to the second recorded initialization weight measurement and the second initialization weight measurement.

[0027] In this way, a trend can be mitigated synergistically and advantageously taken into account, while at the same time excessive changes in the measurement channels compared to the delivery state can be considered. This can increase the availability while maintaining the reliability of the device.

[0028] According to a preferred embodiment, the control unit can further be configured to issue an error message with a request to check the measurement conditions if the first initialization weight measurement is greater than the first limit value and the second initialization weight measurement is greater than the second limit value, and if the difference between the first initialization weight measurement and the second initialization weight measurement is less than a tolerance limit value.

[0029] If both initial weight readings change by the same amount, it can be assumed that the cause lies in the measurement conditions and not in the hardware and / or software of the measurement channels. For example, there may have been a temperature increase or mechanical stress on the device. The device addresses this by performing an additional check of the initial weight readings against each other and then issuing a corresponding error message.

[0030] In this way, errors in the measurement conditions can be detected efficiently.

[0031] According to a preferred embodiment, the control unit can further be configured to compare, during operation, a difference between the weight determined by the first measuring channel and the weight determined by the second measuring channel with an operating limit value, and if the difference is greater than the operating limit value, to issue an error message.

[0032] The first measuring channel, for example, provides the result for the weight of a given quantity of liquid. The second measuring channel can preferably be used to verify the first measuring channel. The operating limit is, for example, ±10g. Here, a comparison of both measuring channels during actual operation additionally verifies whether the amplification factor and the corresponding measured value are correct for weight determination. If the difference between the two weights is too large, this may indicate that the measuring channel is defective.

[0033] In this way, the reliability of the device can be advantageously increased.

[0034] According to a preferred embodiment, the control unit can be configured to evaluate a further acquired first initialization weight measurement of the first measuring channel with previously acquired first initialization weight measurements of the first measuring channel with regard to a trend over the lifetime of the device, and to evaluate a further acquired second initialization weight measurement of the second measuring channel with previously acquired second initialization weight measurements of the second measuring channel with regard to a trend, wherein the control unit is in particular configured to issue an error message when a trend has been identified in the first measuring channel and / or the second measuring channel.

[0035] Analyzing the initialization weight measurements for trends allows for the identification of gradually changing conditions and the early generation of error messages. These trends can indicate an impending failure of the device. In this way, the device's availability can be advantageously increased.

[0036] Another aspect of the present disclosure relates to a computer-implemented method for operating a device for weighing a liquid, wherein the device comprises a control unit, a weighing sensor unit with a first measuring channel and a second measuring channel, and a mounting unit for attaching a container, wherein the computer-implemented method comprises the steps of: acquiring, in an unloaded state, a first initialization weight measurement via the first measuring channel and a second initialization weight measurement via the second measuring channel (S1) before weighing the quantity of liquid; comparing the acquired first initialization weight measurement with a first limit value and the second initialization weight measurement with a second limit value (S2);Setting the acquired first initialization weight measurement as an offset for the first measurement channel and the acquired second initialization weight measurement as an offset for the second measurement channel if the first initialization weight measurement is less than the first limit and the second initialization weight measurement is less than the second limit (S3); Outputting an error message if the first initialization weight measurement is greater than the first limit and / or the second initialization weight measurement is greater than the second limit (S4).

[0037] This method increases measurement accuracy by using a more precise offset in each measurement. It also increases the availability of the liquid weighing device by preventing error messages caused by gradual deterioration through the need for recalibration. Furthermore, the described calibration allows for setting higher limits for the first and / or second limit values ​​before each measurement run. This can also improve the device's availability.

[0038] According to a preferred embodiment, the error message may include a request to check the device with regard to measurement conditions.

[0039] In this way, the availability of the device can be advantageously increased.

[0040] According to a preferred embodiment, after checking the device with regard to the measurement conditions, steps S1 to S4 can be carried out again.

[0041] In this way, the overall availability of the device can be increased, as the necessary inspection by a technician with new, complex calibration can be avoided.

[0042] According to a preferred embodiment, a method can be provided that further comprises: comparing a first difference between the first acquired initialization weight measurement and a first output initialization weight measurement with a first absolute limit; comparing a second difference between the second acquired initialization weight measurement and a second output initialization weight measurement with a second absolute limit; setting the acquired first initialization weight measurement as an offset for the first measurement channel and the acquired second initialization weight measurement as an offset for the second measurement channel if the first difference is less than the first absolute limit and the second difference is less than the second absolute limit; and issuing an error message if the first difference is greater than the first absolute limit and / or the second difference is greater than the second absolute limit.

[0043] In this way, a trend can be mitigated synergistically and advantageously taken into account, while at the same time excessive changes in the measurement channels compared to the delivery state can be considered. This can increase the availability while maintaining the reliability of the device.

[0044] Another aspect of the present disclosure relates to a computer program product, comprising instructions which, when the program is executed by a computer or microprocessor, cause it to perform the procedure described above.

[0045] Another aspect concerns a computer-readable storage medium, comprising instructions which, when executed by a computer or microprocessor, cause it to perform the procedure described above.

[0046] Another aspect concerns an extracorporeal blood treatment machine, in particular a dialysis machine, with a device described in more detail above.

[0047] The units according to one or more embodiments can be implemented using hardware, software, and / or a combination thereof. The units can be single-part or multi-part. Hardware units can be implemented, for example, by processing circuits such as a processor, central processing unit (CPU), controller, arithmetic logic unit (ALU), digital signal processor, microcomputer, field-programmable gate array (FPGA), system-on-chip (SoC), programmable logic unit, microprocessor, or any other device capable of responding to instructions and executing them in a defined manner.

[0048] The units may comprise one or more interface circuits. In some examples, the interface circuits may include wired or wireless interfaces connected to a local area network (LAN), the internet, a wide area network (WAN), or combinations thereof. The functionality of a particular unit of this disclosure may be distributed among several units connected via interface circuits.

[0049] The units according to one or more embodiments may also include one or more storage devices. The one or more storage devices may be physical or non-transient computer-readable storage media, such as random-access memory (RAM), read-only memory (ROM), a permanent mass storage device (e.g., a hard disk drive), a solid-state device (e.g., NAND flash), and / or any other data storage mechanism capable of storing and recording data. The one or more storage devices may be configured to store computer programs, program code, instructions, or a combination thereof.

[0050] The explanations and advantages of individual embodiments described here also apply analogously to the other embodiments. Various exemplary features of the embodiments can be combined according to the invention wherever this is technically sensible and feasible. Brief description of the characters Fig. Figure 1 is a representation illustrating a device for weighing a liquid in a dialysis machine according to a first embodiment of the present disclosure; Fig. Figure 2 is a diagram of the progression of an offset over several measurement cycles without using the device according to the disclosure; Fig. 3 is a diagram of the progression of an offset over several measurement cycles without the use of a device as disclosed; Fig. Figure 4 is a diagram of a further progression of an offset over several measurement cycles using a device according to the disclosure; and Fig. Figure 5 is a diagram comparing a first initialization weight measurement and a second initialization weight measurement. Description of the exemplary implementations

[0051] The following are examples of embodiments of the present disclosure based on the accompanying figures.

[0052] Fig. Figure 1 shows a device 10 for weighing a quantity of liquid in a dialysis machine 14. The liquid is contained in a container 13. From this container 13, the liquid flows, for example, into a patient (not shown) or into a filter unit (not shown) of the dialysis machine 14. Alternatively, a quantity of liquid, such as used dialysis fluid / dialysate, can also flow into this container 13. For this purpose, the container 13 has at least one opening (inlet or outlet). The device 10 includes a mounting unit 11 for receiving the container 13. The mounting unit 11 comprises a hook 12 as an interface for receiving the container 13. This hook can be connected to the mounting unit 11, for example, by a positive locking, force locking, or material locking mechanism. The mounting unit 11 is connected to a frame element 14.The frame element 14 corresponds to the dialysis machine 14. The device 10 further comprises a weighing sensor unit 15 with two measuring channels 16 and 17 for measuring a first weight value and a second weight value. The two measuring channels measure the load acting on the mounting unit 11 and / or the hook 12. Each of the two measuring channels has strain gauge sensors, hardware, and software for determining the weight values. The measuring channels are identical in this case. Alternatively, they can also be different. The device 10 further comprises a control unit 18. The control unit 18 is arranged in the mounting unit 11 in this case. Alternatively, the mounting unit can also be arranged spatially separately from it, for example, in the dialysis machine 14.The control unit 18 is configured to determine the weight of the liquid in container 13 based on the first and second recorded weight measurements. Specifically, the control unit 18 determines the weight by using the first weight measurement as the value for the liquid in container 13. Furthermore, the control unit 18 is configured to calculate the difference between the first and second weight measurements and compare this difference to a limit value. The limit value is 10 g. Finally, if the difference exceeds the limit value, the control unit 18 is configured to issue an error message (e.g., excessive measurement deviation between the measuring channels).The control unit 18 is further configured to output the weight of the liquid quantity in the container 13 if the difference does not exceed the operating limit value. The weighing sensor unit 15 is configured to acquire a first initialization weight measurement via the first measuring channel 16 and a second initialization weight measurement via the second measuring channel 17 before weighing the liquid quantity in an unloaded state (S1). In this case, the weighing sensor unit 15 is unloaded when no container 13 is suspended from the hook 12. The control unit 18 is further configured to compare the acquired first initialization weight measurement with a first limit value and to compare the second initialization weight measurement with a second limit value (S2). The first and second limit values ​​are each preferably ±20 g.Furthermore, the control unit 18 is configured to set the first initialization weight measurement as the offset for the first measurement channel and the second initialization weight measurement as the offset for the second measurement channel if both the first initialization weight measurement is less than the first limit value and the second initialization weight measurement is less than the second limit value (S3). In this case, for example, the first initialization weight measurement is 17g. Thus, the first initialization weight measurement is less than the first limit value, which is ±20g. In this case, the second initialization weight measurement is, for example, 23g. Thus, the second initialization weight measurement is greater than the second limit value, which is ±20g. Therefore, the control unit 18 does not set any new offsets for the first and second measurement channels.Furthermore, control unit 18 is configured to issue an error message (S4) if the first initialization weight measurement is greater than the first limit value and / or the second initialization weight measurement is greater than the second limit value. In this case, the second initialization weight measurement of 23 g is greater than the second limit value of ±20 g. Therefore, control unit 18 issues an error message. This error message includes a request to check the device with regard to the measurement conditions. The error message is displayed on a screen of device 10. Optionally, the error message can also include, for example, a check of hook 12 or of device 10 as a whole.Alternatively, if both initialization weight measurements were smaller than the corresponding limit values, the control unit 18 would use the two initialization weight measurements as an offset for the respective measurement channels, so that both measurement channels would display a weight of 0g in the unloaded state.

[0053] Furthermore, control unit 18 compares a first difference between the first recorded initialization weight measurement and a first output initialization weight measurement with a first absolute limit. The first output initialization weight measurement was determined during the manufacturing of the device. The first absolute limit is ±100g. Control unit 18 also compares a second difference between the second recorded initialization weight measurement and a second output initialization weight measurement with a second absolute limit. The second output initialization weight measurement was also determined during the manufacturing of the device. The second absolute limit is ±100g. The differences are each smaller than the absolute limits, so no error message is issued.

[0054] Furthermore, if the first initialization weight measurement is greater than the first limit value and the second initialization weight measurement is greater than the second limit value, the control unit 18 calculates the difference between the first and second initialization weight measurements and compares this difference to a tolerance limit. The tolerance limit is, for example, 5 g. If the difference is less than the tolerance limit, the control unit 18 issues an error message prompting a check of the measurement conditions. In this case, only the second initialization weight measurement is greater than the second limit value, so this check is not performed.

[0055] Fig. Figure 2 shows the course 50 of the offset over a multitude of measurements for a device for weighing a quantity of liquid, which does not correspond to the device as disclosed. The vertical axis 51 shows the offset for an unloaded state of the device. The horizontal axis 52 shows the number of measurements taken with the device. During the first measurement 53, for example, in the production plant, a corresponding offset is determined and readjusted so that the device displays zero as the measured value during the second measurement 54. Over the course of the measurements, the offset increases. During the twelfth measurement 55, the measured value in the unloaded state exceeds a limit value. The limit value is, for example, 20 g in this case. In this case, a technician must then perform a complex calibration of the device (e.g., with a measuring weight) so that it again displays zero as the measured value during the thirteenth measurement.After that, the offset increases again across the individual measurements until the limit is exceeded once more at the eighteenth measurement (56).

[0056] Fig. Figure 3 shows the curve 70 of the offset over a large number of measurements for another device for weighing a quantity of liquid, which does not correspond to the device disclosed. The vertical axis 71 shows the offset for an unloaded state of the device. The horizontal axis 72 shows the number of measurements with the device. In contrast to curve 50, no recalibration is performed here when a limit value is exceeded by a technician. Curve 70 increases continuously.

[0057] Fig. Figure 4 shows the course 90 of the offset over a multitude of measurements for a device according to the disclosure for weighing a quantity of liquid. The vertical axis 91 shows the offset for an unloaded state of the device 10 for the first measuring channel. It should be noted that the explanations apply analogously to the second measuring channel. The horizontal axis 92 shows the number of measurements with the device 10. This shows that, for example, no new deviation was measured in the first two measurements 93 and 94, but a new deviation was measured in the third measurement 95. This third measurement was then chosen as the new offset. Overall, it can be seen that the offset is recalculated before each actual measurement. This can also be described as autocalibration.

[0058] Furthermore, it can be seen in area 96 that the measurements are increasing disproportionately. The control unit 18 evaluates the respective initialization weight measurements with regard to such an increase or trend by, for example, calculating the differences between successive initialization weight measurements and comparing them. If such a trend is detected, the control unit 18 issues a corresponding error message. The error message may, for example, include a request to check the environmental conditions.

[0059] Furthermore, the diagram shows a first initialization weight measurement 97. This first initialization weight measurement 97 is 4g. For example, the first absolute limit mentioned above is 7g. The first initialization weight measurement 98 is 12g. The corresponding difference between the first initialization weight measurement 98 and the first initialization weight measurement is 8g, which is greater than the first absolute limit of 7g. In this case, an error message would be issued, requiring a technician to recalibrate the device.

[0060] Furthermore, the first limit value is, for example, 6g. A measured value of 99 would exceed the first limit value of 6, so an error message is issued.

[0061] Fig.Figure 5 shows a comparison of a weight 100 from the first measuring channel 16 and a weight 101 from the second measuring channel 17, which were determined during operation of the device 10. The values ​​for the weights are plotted on the vertical axis 102. The difference between the two weights is 10 g. This difference is therefore less than the operating limit of 20 g. Consequently, the control unit 18 does not issue an error message. Otherwise, the control unit 18 would issue an error message. Reference symbol list 10 Device 11 Mounting unit 12 hooks 13 containers 14 frame element, dialysis machine 15 weighing sensor unit 16 first measuring channel 17 second measuring channel 18 Control unit 50, 70, 90 Gradient Offset 51, 71, 91, 102 Vertical axis 52, 72, 92 Horizontal axis 53, 54, 55, 56 individual measurements without mechanical load 93, 94, 95 individual measurement with subsequent autocalibration 96 areas with a trend 97 Initialization Weight Measurement 98 individual measurements greater than the limit value 99 Measurement 101 Weight of first measuring channel 102 Weight of second measuring channel

Claims

[1] Device (10) for weighing a quantity of liquid in an extracorporeal blood treatment machine, comprising: a fastening unit (11) designed to attach a container (13) for the quantity of liquid to a frame element (14); a weighing sensor unit (15) with a first measuring channel (16) and a second measuring channel (17), wherein the weighing sensor unit (15) is configured to acquire a first weight measurement via the first measuring channel (16) and to acquire a second weight measurement via the second measuring channel (17); a control unit (18) which is configured to determine a weight for the quantity of liquid in the container (13) based on the recorded first weight measurement and the recorded second weight measurement; wherein the weighing sensor unit (15) is configured to acquire a first initialization weight measurement via the first measuring channel (16) and a second initialization weight measurement via the second measuring channel (17) before each weighing of the liquid quantity in an unloaded state of the weighing sensor unit (15) (S1); wherein the control unit (18) is configured to compare the detected first initialization weight measurement with a first limit value and to compare the second initialization weight measurement with a second limit value (S2); wherein the control unit (18) is set up: if an amount of the first initialization weight measurement is less than an amount of the first limit value and an amount of the second initialization weight measurement is less than an amount of the second limit value, set the acquired first initialization weight measurement as the offset for the first measurement channel (16) and set the acquired second initialization weight measurement as the offset for the second measurement channel (17) (S3); and If the value of the first initialization weight measurement is greater than the value of the first limit and / or the value of the second initialization weight measurement is greater than the value of the second limit, an error message (S4) is to be issued. [2] Device (10) according to claim 1, wherein the error message includes a request to check the device (10) with regard to measurement conditions. [3] Device (10) according to claim 2, wherein, after checking the device (10) with regard to the measurement conditions, the device (10) is set up to perform steps S1 to S4 again. [4] Device (10) according to one of claims 1 to 3, wherein the control unit (18) is further configured, to compare an initial difference between the first recorded initialization weight measurement and a first initialization weight measurement with a first absolute limit value, to compare a second difference between the second recorded initialization weight measurement and a second initialization weight measurement with a second absolute limit value, if the first difference is less than the first absolute limit and the second difference is less than the second absolute limit, to set the recorded first initialization weight measurement as the offset for the first measurement channel (16) and to set the recorded second initialization weight measurement as the offset for the second measurement channel (17), If the first difference is greater than the first absolute limit and / or the second difference is greater than the second absolute limit, an error message should be displayed. [5] Device (10) according to one of claims 1 to 4, wherein the control unit (18) is further configured to issue an error message with a request to check the measurement conditions if the first initialization weight measurement is greater than the first limit value and the second initialization weight measurement is greater than the second limit value, and if a difference between the first initialization weight measurement and the second initialization weight measurement is less than a tolerance limit value. [6] Device (10) according to one of claims 1 to 5, wherein the control unit (18) is further configured to compare, during operation, a difference between the weight determined by the first measuring channel (16) and the weight determined by the second measuring channel (17) with an operating limit value, and if the difference is greater than the operating limit value, to output an error message. [7] Device (10) according to one of claims 1 to 6, wherein the control unit (18) is configured to evaluate a further detected first initialization weight measurement of the first measuring channel (16) with previous detected first initialization weight measurements of the first measuring channel (16) with regard to a trend over a lifetime of the device (10) and to evaluate a further detected second initialization weight measurement of the second measuring channel (17) with previous detected second initialization weight measurements of the second measuring channel (17) with regard to a trend, wherein the control unit is in particular configured to output an error message when a trend has been identified in the first measuring channel (16) and / or second measuring channel (17). [8] Computer-implemented method for operating a device (10) for weighing a liquid, wherein the device (10) comprises a control unit (18), a weighing sensor unit (15) with a first measuring channel (16) and a second measuring channel (17), and a fastening unit (11) for fastening a container (13), wherein the method comprises the steps: Each time before weighing the quantity of liquid in an unloaded state, the weighing sensor unit (15) acquires a first initialization weight measurement via the first measuring channel (16) and a second initialization weight measurement via the second measuring channel (17) (S1); Comparing the recorded first initialization weight measurement with a first limit value and the second initialization weight measurement with a second limit value (S2); Setting the acquired first initialization weight measurement as an offset for the first measurement channel (16) and the acquired second initialization weight measurement as an offset for the second measurement channel (17) if the first initialization weight measurement is less than the first limit value and the second initialization weight measurement is less than the second limit value (S3); Output an error message if the first initialization weight measurement is greater than the first limit and / or the second initialization weight measurement is greater than the second limit (S4). [9] Method according to claim 8, wherein the error message includes a request to check the device (10) with regard to measurement conditions. [10] Method according to claim 8 or 9, wherein after checking the device (10) with regard to the measurement conditions, the device (10) is set up to perform steps S1 to S4 again. [11] Method according to any one of claims 8 to 10, further comprising the steps: Comparing an initial difference between the first recorded initialization weight measurement and an initial initialization weight measurement with an initial absolute limit, Comparing a second difference between the second recorded initialization weight measurement and a second initialization weight measurement with a second absolute limit, Setting the acquired first initialization weight measurement as the offset for the first measurement channel (16) and the acquired second initialization weight measurement as the offset for the second measurement channel (17) if the first difference is less than the first absolute limit and the second difference is less than the second absolute limit; Output an error message if the first difference is greater than the first absolute limit and / or the second difference is greater than the second absolute limit. [12] Computer program product comprising instructions which, when the program is executed by a computer or microprocessor, cause it to execute the method according to any one of claims 8 to 11. [13] Computer-readable storage medium comprising instructions which, when executed by a computer or a microprocessor, cause it to execute the method according to any one of claims 8 to 11. [14] Extracorporeal blood treatment machine (14) with a device (10) according to any one of claims 1 to 7.

Images