Reverse osmosis system for medical applications and method for operating the reverse osmosis system

Abstract

2.1 Such a reverse osmosis system with at least one fluid line and with a liquid tank and with at least one filter membrane, which are integrated into the at least one fluid line, and with the following functional components assigned to the at least one fluid line is known: - at least one pressure sensor, - at least one volume flow sensor, - at least one pump, - at least one electrically activated fluid control component without signal feedback function. 2.2 According to the invention, a function testing device is provided for the at least one electrically activatable fluid control component, which, upon activation of the fluid control component, records sensor data from a pressure or volume flow sensor system adjacent to the fluid line side and evaluates them in a time-dependent manner. 2.3 Use for medical applications

Description

The invention relates to a reverse osmosis system for medical applications, having at least one fluid line and having a liquid tank and having at least one filter membrane which are integrated into the at least one fluid line, and having the following functional components assigned to the at least one fluid line:at least one pressure sensor system,at least one volume flow sensor system,at least one pump,at least one electrically activatable fluid control component without a signal feedback function, in particular at least one solenoid valve.The invention also relates to a method for operating such a reverse osmosis system.Reverse osmosis plants for medical applications are generally known. In order to carry out a functional check of such reverse osmosis systems, system tests are carried out. A prerequisite for this is that the functional components of such a reverse osmosis system are designed in such a way that they can send digital or analog electrical signals on request by a corresponding functional test device, which are subsequently evaluated by the functional test device. Such system tests only work with functional components that have a corresponding signal feedback function. Electrically activatable fluid control components, such as in particular electromagnetic switching valves, referred to for short as solenoid valves, do not have such a signal return function, so that they cannot also be checked for their function using known system tests.It is an object of the invention to provide a reverse osmosis system and a method for operating this reverse osmosis system of the type mentioned at the beginning, which enable comprehensive function checking of all functional components with little effort.This object is achieved for the reverse osmosis system by the features of claim 1. For the method for operating the reverse osmosis system, the object on which the invention is based is achieved by the features of claim 11.According to the invention, a function checking device for the at least one electrically activatable fluid control component without a signal return function is provided for the reverse osmosis system, which device detects sensor data of a pressure or volume flow sensor system adjacent to the fluid line side when the fluid control component is activated and evaluates it in a time-dependent manner. As a fluid control component without a signal feedback function, at least one electromagnetic switching valve, referred to below as a solenoid valve, is provided in particular. If the corresponding fluid control component is intact, a significant change in the data signals of the pressure sensor system and / or of the volume flow sensor system inevitably occurs upon activation. Depending on the hydraulic configuration and the function checking method, a combination of pressure and volume flow can also be used as acceptance criterion. The corresponding change is detected and, if the change is sufficiently high, leads to the result that the fluid control component, in particular the solenoid valve, functions, i.e. is intact. The detection and evaluation take place time-dependently over a time period predefined by the function checking device. If a corresponding change of the sensor system data to the predefined extent does not take place within this time period, the fluid control component is evaluated as defective. The solution according to the invention is suitable in particular for reverse osmosis systems which are used in the field of hemodialysis. In the same way, the reverse osmosis system according to the invention can also be used for other medical applications for which a corresponding water treatment is necessary. The solution according to the invention enables information about the functionality of the reverse osmosis plant. In the case of corresponding defects, further measures such as, in particular, a shutdown of the system, an initiation of an emergency operation and the like can be initiated. Because the fluid control components are electrically activated regularly for the function checking without signal feedback and are consequently opened and closed, a mechanical fixing of the fluid control components as well as a greater nucleation in the region of the fluid control components can be avoided. A standstill time of these fluid control components is thus necessarily reduced by the solution according to the invention. Corresponding test results of the functional check can also be detected by remote diagnosis, as a result of which repairs of the reverse osmosis system can be carried out more quickly and economically.In one embodiment of the invention, the function checking device has an evaluation unit for the sensor data, which compares data changes with reference data that occur with time when the fluid control component is intact. If the predefined time period is exceeded, it is assumed that the corresponding fluid control component is defective.In a further embodiment of the invention, the evaluation unit uses a predetermined amount of a data change independently of a starting level of the sensor data in order to confirm the presence of a sufficient function. The evaluation unit accordingly only checks the amount of change in the sensor data over the predefined time period. A minimum value stored in the evaluation unit is added to a corresponding starting level. If this is reached within the predefined time period, an intact fluid control component is present. Thus, a dynamic starting level is present, which can be specified specifically for the installation and functional components.In a further embodiment of the invention, the acquired sensor data are stored and used for evaluating wear states of the functional components and for creating a wear prediction model. Regularly repeated functional checks of the reverse osmosis system according to the invention make it possible to monitor the wear of functional components, trends in opening duration, closing duration or sensor accuracy being detected. Through the use of algorithms, wear predictions can be made or changes in function values can be tracked. This simplifies the creation of remote diagnoses.In a further embodiment of the invention, the function checking device has a sensor system checking unit which carries out an electrical function checking of the at least one pressure or volume flow sensor system on the basis of electrical input signals of the sensor system. The pressure or volume flow sensor system is provided with a signal return function, so that when the sensor system checks the corresponding pressure or volume flow sensor system, feedback is effected by corresponding sensor signals. In the sensor system test unit, these input signals are compared with predetermined lower and upper limit values. This embodiment is advantageously used before the electrically activatable fluid control component is tested without a signal feedback function. If the input signal of the pressure or volume flow sensor system lies within these limit values, the pressure or volume flow sensor system is intact.In a further embodiment of the invention, the function checking device has a pump checking unit which carries out an electrical function checking of the at least one pump on the basis of electrical pump signals. The at least one pump also has a signal return function. Upper and lower limit values are preset in the pump test unit. If the electrical pump signals received by the pump are within these limit values, the pump is deemed intact. Electrical pump signals can be embodied as binary levels, as digital signals, as analog signals or as fieldbus signals. These signals are preferably obtained from automatic fuse units or from frequency converters of corresponding pumps. Analog signals can be carried out via a 4-20 mA signal feedback of a current pump speed. The at least one pump can be frequency controlled so that a pump speed can be changed. The at least one pump can, however, also be operated at constant speed. Such a pump is not frequency controlled. The function checking of the at least one pump preferably also takes place before checking the function of the electrically activatable fluid control component, in particular of the at least one solenoid valve.In a further embodiment of the invention, the function checking device has a tank checking unit which checks a minimum fill level of the liquid tank and outputs a signal as a function of a result of the check. This embodiment ensures that, if the fill level is too low, the at least one pump does not run dry and can thus be damaged. This check is also preferably carried out before the function check of the at least one electrically activatable fluid control component without a signal return function.In a further embodiment of the invention, a pump control device is provided in order to achieve a pump rotational speed of the at least one pump in order to achieve a steady state in the fluid circuit. A corresponding stationary state is required for the reverse osmosis reaction in the region of the at least one filter membrane. The reverse osmosis system preferably has at least two pumps which are realized by at least one pressure pump and at least one circulation pump.In a further embodiment of the invention, the function checking device is assigned an electronic data processing device in which at least one wear model for the function components is stored, and which has an evaluation unit which records data sets of the incoming sensor data and compares them with the wear model and evaluates them with regard to a failure prediction of the function components. This embodiment enables an early exchange of functional components of the reverse osmosis system as well as the improvement of the accuracy of the evaluation of sensor data of the pressure sensor system and of the volume flow sensor system. The electronic data processing device can be spatially assigned to the function checking device or locally separated from it. In the latter case, the assignment takes place in particular via a cloud connection.In a further embodiment of the invention, a process data adaptation for operation of the functional components is stored in the electronic data processing device, which process data adaptation controls or regulates the functional components depending on the wear of incoming sensor data. The process data adaptation is preferably stored as software in the data processing device. By means of this configuration, it is possible to adapt parameters for the operation of the reverse osmosis system. Component wear in individual functional components can degrade the accuracy of consumption data. By corresponding updating of the values by means of the described embodiment, an adjustment is made possible which restores the accuracy of the process data. If the level of a consumed permeate volume flow is required, water flowing via a flow restrictor must be drawn off from a produced permeate volume flow, measured via a volume flow sensor system. Due to corresponding component wear, the volume of the permeate flowing back can change over time. Over time, this would also impair the accuracy of the consumed permeate volume flow. The process data adjustment prevents such degradation.For the method for operating the reverse osmosis system of the type mentioned at the beginning, the at least one fluid control component is electrically activated without a signal return function and then checked for its function by a time-dependent detection of changes in the volumetric flow or pressure of the liquid adjacent to the fluid line side. Before an electrical activation of the fluid control components without a signal return function, a function check of the remaining function components assigned to the at least one fluid line is advantageously carried out by detecting electrical signals of the function components and comparing them with lower and upper predefined limit values and subsequently outputting a result of the function check. Advantageously, a fill level check of the liquid tank is also carried out before the at least one fluid control component is electrically activated without a signal return function. The at least one pump is also advantageously controlled in order to establish a steady state in the at least one fluid line, wherein only after the steady state is established is the at least one fluid control component electrically activated without a signal return function.The sequences described ensure system test sequences which make possible reliable conclusions about the function of the various functional components of the reverse osmosis system.Further advantages and features of the invention are evident from the claims and from the following description of preferred exemplary embodiments of the invention, which are illustrated on the basis of the drawings. FIG. 1 schematically shows an embodiment of a single-stage reverse osmosis plant according to the invention, FIG. 2 schematically shows an embodiment of a two-stage reverse osmosis system according to the invention, and FIG. 3 shows an embodiment of a three-stage reverse osmosis system according to the invention.Both the single-stage reverse osmosis system according to FIG. 1 and the multistage reverse osmosis systems according to FIGS. 2 and 3 are provided for medical applications. Identical reference numerals are used for all respectively identical functional components of the different reverse osmosis installations according to FIGS. 1 to 3. The respective reverse osmosis system is provided with the reference symbol 100. Each reverse osmosis system 100 has a liquid tank 102, from which liquid is introduced via a pressure pump 104 into a circulatory fluid line. Downstream of the pressure pump 104, a filter membrane 105 is provided, via which concentrate is discharged into a fluid line, to which a circulation pump 109 is assigned. A volume flow sensor 106 is assigned upstream of the circulation pump 109. Concentrate is discharged from this fluid line via an electrically activatable fluid control component without a signal return function, in the present case by a solenoid valve 108. This concentrate outlet is assigned a further volume flow sensor 107.In all the installations according to FIGS. 1 to 3, liquid is supplied via a supply line which can be opened or closed via a further solenoid valve 101, i.e. a further electrically activatable fluid control component without a signal return function. The feed line opens into the liquid tank 102. The liquid tank 102 is provided with a pressure sensor 103 that detects a level of the liquid tank 102.In the single-stage reverse osmosis system 100 according to FIG. 1, a ring line 117 is provided, which leads liquid back into the liquid tank 102 via a fluid line. In a manner not shown in detail, consumers are connected to the ring line 117 which draw permeate out of the circuit if necessary. This fluid line is assigned a further pressure sensor 118. The fluid line is provided upstream of the liquid tank 102 with a flow restrictor 120 and with a bypass valve 119 connected in parallel. A volume flow sensor 116 is assigned to the fluid line section of the reverse osmosis system, which leads to the ring line 117.In the two-stage reverse osmosis system 100 according to FIG. 2, the structure of the single-stage reverse osmosis system 100 according to FIG. 1 is supplemented by a further circulation and a further filter membrane 112. Downstream of the filter membrane 105 there is connected a fluid line which has a branch to a further pressure pump 111, a further filter membrane 112 and a circulation line having a circulation pump 115 and a volume flow sensor 113. The corresponding discharge line is connected directly to the liquid tank 102, wherein this connecting line can be shut off or released via a solenoid valve 114. The supply line for liquid has a line which can be shut off by a further solenoid valve 121 and leads to the second pressure pump 111 and to the second filter membrane 112. Behind the discharge line to the second pressure pump 111, a further solenoid valve 122 is provided. Upstream of the second pressure pump 111, a pressure sensor 110 is incorporated into the fluid line. Downstream of the second filter membrane 112, an annular conduit 117 directs corresponding liquid back to the liquid tank 102. The construction of the throughflow limiter 120 and the overflow valve 119 with the upstream pressure sensor 118 and the volume flow sensor 116 to the ring line 117 is identical to the single-stage reverse osmosis system.In the three-stage reverse osmosis apparatus, the structure of the two-stage reverse osmosis apparatus is used. In addition, a third circulation circuit is also assigned to a third filter membrane 126, a third pressure pump 125, a third circulation pump 129, a pressure sensor 124 connected upstream of the pressure pump 125 and a volume flow sensor 127 assigned to the discharge line of the filter membrane 126. A return line to the liquid tank 102 is blockable by a solenoid valve 128. A solenoid valve 123 allows the liquid to be conducted to the liquid tank 102 via the third circulation circuit or to be returned to the liquid tank 102 via the ring line 117, depending on whether it is closed or open. Here too, consumers are assigned to the ring line 117 in a manner not shown in more detail, which draw permeate out of the circuit if necessary.For all three reverse osmosis installations 100, a function checking device is provided, which is not shown in the drawing. By means of the function checking device, the functions of the individual functional components of the reverse osmosis systems 100 are checked and monitored. The function checking device has an electronic data processing device which is connected to the individual functional components of the reverse osmosis system 100 according to FIGS. 1 to 3 in the manner described in more detail below.In order to perform a functional check of the single-stage reverse osmosis system 100, the pressure pump 104 and the circulation pump 109 are started. The solenoid valve 108 is then opened. The function checking device is connected to the upstream adjacent volume flow sensor 107. Opening of the solenoid valve 108 changes the volume flow in the fluid line. The corresponding change in the volume flow is detected by the volume flow sensor 107. The function checking device evaluates the acquired sensor data in a time-dependent manner. As soon as a threshold value for the change of the volume flow is detected within a predefined time period, the solenoid valve 108 is deemed intact. To end the corresponding test step, the solenoid valve 108 is closed.Subsequently, the solenoid valve 101 is opened. The fill level of the liquid tank 102 is monitored via the pressure sensor 103. This is coupled to the function checking device, more precisely to a tank checking unit of the function checking device. When the solenoid valve 101 is opened, the fill level of the liquid tank 102 must increase, since liquid can then flow from the feed line into the liquid tank 102. As a result, the pressure in the liquid tank 102 increases. This pressure change is detected in a time-dependent manner via the function checking device. The function checking device specifies a threshold value that the change in the pressure of the pressure sensor 103 must exceed within a predefined time period. If this is the case, the solenoid valve 101 is deemed intact. In this case, the threshold value, which is also referred to as a level, is dynamic. At the beginning of the corresponding checking step, this is determined. In this case, a starting level is used at the beginning of the valve opening. To define the threshold value, a minimum value is added to this starting level, so that a dynamic threshold value results. At the end of the test step, the solenoid valve 101 is closed again.Subsequently, the pumps, i.e. the pressure pump 104 and the circulation pump 109, are closed again.In the two-stage reverse osmosis system according to FIG. 2, likewise when the test sequence is started, the function checking device first activates both the pressure pump 104 and the circulation pump 109. After the two pumps 104 and 109 have been started, the solenoid valve 108 is opened in a similar manner to the test sequence in the single-stage reverse osmosis system and a volume flow change at the upstream adjacent volume flow sensor 107 is detected and evaluated by means of the function checking device. If the predefined threshold value for the volume flow change is reached as a function of time, the solenoid valve 108 is closed again. The solenoid valve 108 is then considered intact.Subsequently, similarly to the single-stage reverse osmosis system, the solenoid valve 101 is opened and the change in the fill level of the liquid tank 102 is monitored via the pressure sensor 103. Finally, the solenoid valve 101 is closed again as soon as it has been evaluated as intact.In a next test step, the solenoid valve 122 is opened. A pressure fluctuation arising as a result is monitored in the ring line 117 via the pressure sensor 118. When a desired change occurs within the predetermined time period, the solenoid valve 122 is closed again. It is then considered intact. In this case, the threshold value which must be exceeded by monitoring the pressure sensor 118 is dynamically defined. The print start level is used and an added minimum value is added to this. If the threshold value is exceeded within the predefined time period, the solenoid valve 122 is deemed to be functional. It is closed again.In a next test step, the pressure pump 111 and the circulation pump 115 of the second stage of the reverse osmosis system are started. The solenoid valve 114 is then opened. The function checking device monitors a corresponding volume flow change at the upstream adjacent volume flow sensor 113. Depending on the detected volume flow change, the function checking device evaluates the functionality of the solenoid valve 114. If the magnetic field 114 is intact, it remains open for the subsequent test step in order to keep a pressure in the corresponding fluid line segment as low as possible.Subsequently, all the pumps, i.e., both the pressure pumps 104 and 111 and the circulation pumps 109 and 115, are stopped. For the next test step, the solenoid valve 121 is opened and monitored via the pressure sensor 110 adjacent downstream. In the event of a corresponding increase in pressure within a predefined time period, the function checking device recognizes whether the solenoid valve 121 is intact. After completion of this test step, both the solenoid valve 114 and the solenoid valve 121 are closed.In the three-stage reverse osmosis system according to FIG. 3, in addition to the solenoid valves of the two-stage reverse osmosis system according to FIG. 2, two further solenoid valves 123 and 128 are checked for their function. In a first test step, the solenoid valve 122 is opened for this last stage. Corresponding pressure changes are monitored via the pressure sensor 124 in the third stage fluid line section. If the function checking device, analogously to the above-described test sequences, also determines here by means of the pressure sensor 124 that the solenoid valve 122 is intact, the solenoid valve 123 is opened in a further test step. The downstream adjacent pressure sensor 118 is monitored by the function checking means. If the pressure change desired over the predefined time period results according to the predefined threshold value, the solenoid valve 123 is deemed intact.In a final test step, the solenoid valve 128 is opened. For this test step, it is necessary that the pumps are active and have reached a steady state in the cycle. A volume flow in this fluid line segment is monitored via the volume flow sensor 127, which is provided upstream of the solenoid valve 128 in the fluid line segment. Here, too, analogously to the above-described checks, the function checking device monitors whether a minimum value of a corresponding volume flow change results within the predefined time period. If affirmative, the solenoid valve 128 is deemed intact.Based on the above, a defined sequence of switching actuators and sensing sensors has been described. In principle, this sequence can also be deviated from, provided that this is technically possible and expedient.

Claims

Reverse osmosis system (100) for medical application areas with at least one fluid line and with a liquid tank (102) and with at least one filter membrane (105, 112, 126) which are integrated into the at least one fluid line, and with the following functional components assigned to the at least one fluid line: - at least one pressure sensor system, - at least one volume flow sensor system, - at least one pump (104, 109, 111, 115, 125, 129), - at least one electrically activatable fluid control component without a signal return function, in particular a solenoid valve (101, 108, 114, 121, 122, 123, 128), characterized in that a function checking device is provided for the at least one electrically activatable fluid control component, which, when the fluid control component is activated, acquires sensor data of a pressure or volume flow sensor system adjacent on the fluid line side and evaluates it in a time-dependent manner.Reverse osmosis system (100) according to Claim 1, characterized in that the function checking device has an evaluation unit for the sensor data which compares data changes with reference to desired data as a function of time, which changes occur in the case of an intact fluid control component.Reverse osmosis system (100) according to Claim 2, characterized in that the evaluation unit uses a predetermined level of a data change independently of a starting level of the sensor data in order to confirm the presence of a sufficient function.Reverse osmosis system (100) according to Claim 2 or 3, characterized in that the captured sensor data are stored and used for evaluating wear states of the functional components and for generating a wear prediction model.Reverse osmosis system (100) according to one of the preceding claims, characterized in that the function checking device has a sensor system checking unit which carries out an electrical function checking of the at least one pressure or volume flow sensor system on the basis of electrical input signals of the sensor system.Reverse osmosis system (100) according to one of the preceding claims, characterized in that the function checking device has a pump checking unit which carries out an electrical function checking of the at least one pump (104, 109, 111, 115, 125, 129) on the basis of electrical pump signals.Reverse osmosis system (100) according to one of the preceding claims, characterized in that the function checking device has a tank checking unit which checks a minimum fill level of the liquid tank (102) and outputs a signal as a function of a result of the check.Reverse osmosis system (100) according to one of the preceding claims, characterized in that a pump control device is provided in order to control or regulate a pump rotational speed of the at least one pump (104, 109, 111, 115, 125, 129) in order to achieve a steady state in the at least one fluid line.Reverse osmosis system (100) according to one of the preceding claims, characterized in that the function checking device has an electronic data processing device in which at least one wear model for the function components is stored, and which has an evaluation unit which acquires data sets of the incoming sensor data and compares them with the wear model and evaluates them with regard to a failure prediction of the function components.Reverse osmosis system (100) according to Claim 9, characterized in that the electronic data processing device stores a process data adaptation for operation of the functional components, which process data adaptation controls or regulates the functional components as a function of wear on the basis of incoming sensor data.Method for operating a reverse osmosis system (100) according to the preamble of claim 1, characterized in that the at least one fluid control component is electrically activated without a signal return function and is subsequently checked for its function by a time-dependent detection of adjacent changes in the volume flow or pressure of the liquid on the fluid line side.Method according to Claim 11, characterized in that, before an electrical activation of the fluid control component without a signal return function, a function check of the remaining function components assigned to the fluid circuit takes place by detecting electrical signals of the function components and comparison with lower and upper predefined limit values and subsequent output of a result of the function check.Method according to claim 11 or 12, characterised in that a fill level check of the liquid tank is carried out before the at least one fluid control component is electrically activated without a signal return function.Method according to one of Claims 11 to 13, characterized in that the at least one pump (104, 109, 111, 115, 125, 129) is actuated in order to establish a steady state in the at least one fluid line, and in that, after the steady state has been established, the at least one fluid control component is electrically activated without a signal feedback function, in particular the at least one solenoid valve (101, 108, 114, 121, 122, 123, 128).

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