Control arrangement and control method for sensorless membrane pump

Abstract

To provide a control arrangement improving reliability of process and configuring an inexpensive solution, and a diaphragm pump.SOLUTION: The current invention relates to a control arrangement 13 for controlling a sensorless diaphragm pump 14 and a control method. The control arrangement 13 includes: a control fluid entrance 1 connected to a first control fluid reservoir 1A having a pressure level raised to reference pressure; a control fluid outlet 2 connected to a second control fluid reservoir 2A having a pressure level reduced to the reference pressure; and a control fluid connection 8 for connection of a control fluid line. The control fluid entrance 1 is connected to a collection point 6 through a first proportional valve 3. The control fluid outlet 2 is connected to the collection point 6 through the second proportional valve 4. The mass flow rate sensor 5 is arranged between the collection point 6 and the control fluid connection 8. The control arrangement 13 further has a control unit 12 connected to the first proportional valve 3, the second proportional valve 4, and a mass flow rate sensor 5 in terms of signaling.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control arrangement for controlling a sensor-free diaphragm pump. The present invention further relates to a method for controlling a sensor-free diaphragm pump. The present invention further relates to a diaphragm pump arrangement comprising a diaphragm pump and a control arrangement for controlling the diaphragm pump. The present invention further relates to a diaphragm pump, a diaphragm pump arrangement or a bioreactor comprising a diaphragm pump, and the use of a diaphragm pump arrangement with a bioreactor or in a bioreactor. [Background technology]

[0002] In the field of bioprocessing technology, particularly when bioreactors are used, diaphragm pumps are used to transport media. The media to be transported in bioprocessing technology are in particular fluids that may contain biological cells and / or other components that may be the subject of, for example, research or further utilization. Diaphragm pumps and their use in bioreactors are described, for example, in EP 2 379 889 B1.

[0003] However, there is a need for improved solutions for diaphragm pumps, methods for controlling diaphragm pumps, and control arrangements that increase the reliability of the process and / or constitute particularly inexpensive solutions. Summary of the Invention

[0004] This object is achieved by a control arrangement for controlling a sensorless diaphragm pump, the control arrangement comprising a control fluid inlet for connection to a first control fluid reservoir having an increasing pressure level relative to a reference pressure, a control fluid outlet for connection to a second control fluid reservoir having a decreasing pressure level relative to the reference pressure, and control fluid connections for connection of a control fluid line for the sensorless diaphragm pump, the control fluid inlet being connected to a collection point through a first proportional valve and the control fluid outlet being connected to the collection point through a second proportional valve, a mass flow sensor being arranged between the collection point and the control fluid connections, the control arrangement further comprising a control unit connected in signaling terms to the first proportional valve, the second proportional valve and the mass flow sensor.

[0005] The present invention is based, inter alia, on the realization that existing diaphragm pumps, control arrangements, and methods rely on distance sensors to determine the position of the diaphragm. This not only increases the cost of the diaphragm pump itself, but also inevitably leads to inaccuracies, since the displacement volume is only indirectly determined by the distance sensor and the spatial deformation of the elastic diaphragm cannot be reproducibly accounted for. Furthermore, in many cases, the actuation of the diaphragm and the transport of the transported medium generates high loads on the components of the medium. For example, large shear forces may be generated that can be particularly damaging to biological cells in the transported medium, adversely affecting or even making further investigation and / or processing of the biological cells impossible. Particularly in fields where inexpensive, disposable bioreactors are used, expensive diaphragm pumps with distance sensors become even less attractive.

[0006] In contrast, the control arrangement described herein allows for a configuration that does not require a distance sensor to determine the position of the diaphragm of the diaphragm pump, while at the same time ensuring accurate and gentle delivery of the delivered medium. Thus, for the first time, the use of a sensor-free, and therefore significantly cheaper, diaphragm pump is possible, even in the form of a disposable diaphragm pump in a disposable bioreactor. At the same time, it is guaranteed that the medium and its components delivered by the diaphragm pump are delivered precisely, volumetrically, and gently, thereby increasing the reliability of the process and improving further investigation and further processing.

[0007] This is achieved by the described control arrangement for controlling a sensorless diaphragm pump, which does not rely on the signal of a distance sensor to sense the position of the diaphragm of the diaphragm pump.

[0008] A sensorless diaphragm pump is understood here to be a diaphragm pump which is not provided with a distance sensor for detecting the position of the diaphragm. Preferably, a sensorless diaphragm pump does not include any further sensors.

[0009] Such a configuration of the diaphragm pump has the advantage that the costs of distance sensors and further sensors for detecting the position of the diaphragm can be saved, allowing the diaphragm pump to be produced in a significantly cheaper way, and therefore also applicable in disposable applications.

[0010] The control arrangement described herein is designed to be able to control such a sensorless diaphragm pump, and to this end, the control arrangement comprises the elements described in the subsequent documents.

[0011] The control fluid inlet and the control fluid outlet serve to connect the control arrangement to first and second control fluid reservoirs, the control fluid inlet being connected to the first control fluid reservoir having an elevated pressure level relative to a reference pressure, and the control fluid outlet being connected to the second control fluid reservoir having a reduced pressure level relative to the reference pressure.

[0012] Through the control fluid connection, the control arrangement may be connected by a control fluid line to the sensorless diaphragm pump. In this way, control fluid can flow from the first control fluid reservoir through a control fluid inlet to the control fluid connection and from there through the control fluid line into the interior of the control fluid side chamber of the sensorless diaphragm pump, and from there back through the control fluid line to the interior of the second control fluid reservoir through a control fluid outlet.

[0013] The first and second control fluid reservoirs may be part of an overall control fluid reservoir that, through a control arrangement, provides an increased or decreased pressure level relative to the required reference pressure for the transport of control fluid into and out of the control fluid side chamber of the diaphragm pump.

[0014] Both the control fluid inlet and the control fluid outlet are connected to a collection point, which is connected to a control fluid connection. A first proportional valve is located between the control fluid inlet and the collection point, and a second proportional valve is located between the control fluid outlet and the collection point. Through these proportional valves, the control arrangement can control the flow of control fluid from the control fluid inlet to the control fluid connection and from the control fluid connection to the control fluid outlet. For this purpose, the control arrangement has a control unit connected in terms of signaling to the first proportional valve and the second proportional valve.

[0015] The control arrangement further comprises a mass flow sensor arranged between the collection point and the control fluid connection. The mass flow sensor is preferably in the form of a thermal mass flow sensor. Via the mass flow sensor, the mass flow rate of the control fluid can be determined between the collection point and the control fluid connection. For this purpose, the control unit of the control arrangement is likewise connected in terms of signaling to the mass flow sensor. In this way, it is possible to use the signal of the mass flow sensor in the actuation of the first and / or second proportional valve.

[0016] The control fluid inlet is preferably connected to a collection point via a control fluid line, and the control fluid outlet is likewise connected to the collection point via a control fluid line. The collection point is also preferably connected to a control fluid connection via a control fluid line. The control fluid line connecting the control arrangement to the sensorless diaphragm pump may be further connected to a control fluid connection. Preferably, one control fluid line may be connected to the control fluid inlet and / or the control fluid outlet so as to connect the control fluid inlet and / or the control fluid outlet to the first and / or second control fluid reservoirs in each case.

[0017] The sensorless diaphragm pump has a control fluid side chamber and a media side chamber. A control fluid is introduced into or discharged from the control fluid side chamber by a control arrangement through a control fluid line. The media side chamber is passed through by the conveyed medium. An elastic diaphragm fluidically separates the two chambers from each other but volumetrically engages the chambers. The media side chamber has one or more media connections through which the conveyed medium flows into or out of the media side chamber. To control the flow of the medium, the connections may desirably be provided with valves, such as automatically actuated or controlled valves, particularly check valves.

[0018] In a preferred embodiment, the medium side chamber of the sensorless diaphragm pump has only one medium inlet for the inflow of the medium and only one medium outlet for the outflow of the medium. Preferably, the medium inlet and the medium outlet each have a check valve, in particular a self-actuating check valve, which is positioned according to the flow direction through the respective medium inlet or medium outlet.

[0019] Here, a bioreactor is understood to be, in particular, a flexible or dimensionally stable container that forms a reaction chamber inside in which a bioprocess is carried out. For this purpose, a mixture of media, also called culture broth, is generally located in the bioreactor. Bioreactors usually have one or more connections through which media can be introduced or discharged, samples can be extracted, or sensors for various measurements can be connected. Diaphragm pumps are used in bioreactors to allow the extraction or discharge of media or media samples, or to move and thereby mix the media, for example.

[0020] Bioreactors are generally required to be provided under sterile conditions for bioprocessing. Because sterilization of existing bioreactors is difficult, expensive, and always involves process risks, the use of disposable bioreactors, which are provided for a single use and then discarded, is on the rise. To this end, primarily inexpensive designs and inexpensive materials are required, while at the same time, materials that conserve resources and are environmentally friendly as much as possible and meet bioprocessing technology standards, such as United States Pharmacopeia (USP) Class VI. In this context, disposable diaphragm pumps that form part of disposable bioreactors and that can be similarly discarded together with the disposable bioreactor after use, are also desirable. To this end, inexpensive, resource-saving, and environmentally friendly materials that simultaneously meet high standards for bioprocess safety are desirable.

[0021] The volumetric flow rate of the control fluid may be determined by the mass flow rate of the control fluid sensed by a mass flow sensor, which is related to the molar flow rate. The number of moles and the corresponding delivered volume of the control fluid may be determined by integrating the number of moles over time. In this manner, volumetric actuation of a sensorless diaphragm pump is achieved by the control arrangements described herein.

[0022] On the one hand, the connection of the mass flow sensor in terms of signaling and, on the other hand, the connection to the control unit of the control arrangement by the first and second proportional valves makes it possible to control the flow of control fluid from the control fluid inlet to the control fluid connection and back to the control fluid outlet based on the data detected by the mass flow sensor, in this way compensating for the absence of a distance sensor detecting the position of the diaphragm.

[0023] The control arrangement described herein, by its structure and by locating a mass flow sensor between the collection point and the control fluid connection, is able to combine all elements necessary for the control of a sensorless diaphragm pump in the control arrangement. Thus, only a simple connection to the control fluid reservoir on the one hand and to the sensorless diaphragm pump on the other hand is required. Furthermore, in this way, all control-related sensors and other components are combined in the control arrangement. Thus, a preferably reusable control arrangement may contain all of the potentially complex and expensive components and may be located spatially separated at a distance, for example, from a disposable bioreactor with a sensorless disposable diaphragm pump used therein.

[0024] Preferably, the control arrangement is configured to control multiple sensorless diaphragm pumps. For this purpose, for example, multiple control fluid lines or branching control fluid lines to multiple sensorless diaphragm pumps may be connected to the control fluid connection. In this case, the multiple sensorless diaphragm pumps may preferably all be operated in the same way. This is particularly suitable for parallel bioprocesses carried out in parallel in multiple similarly configured arrangements.

[0025] The control arrangement may preferably be configured to operate several diaphragm pumps in different ways. For this purpose, the control arrangement preferably has a corresponding number of components required in each case. In this way, corresponding components may be combined in a common control arrangement and may be centrally available for operating several diaphragm pumps and for different applications with different operation.

[0026] The control arrangement, particularly when configured to operate multiple diaphragm pumps having different types of actuation, may be configured in a distributed manner, e.g., spatially spaced apart, with corresponding connections (e.g., in terms of signaling and / or fluidly and / or in a line-dependent and / or line-independent manner) to form a coherent control arrangement.

[0027] It is particularly desirable that the mass flow sensor be configured for measurement in both flow directions, and therefore desirably the mass flow sensor is configured to sense the mass flow rate of control fluid between the collection point and the control fluid connection regardless of the flow direction of the control fluid, i.e., whether the control fluid flows from the control fluid inlet to the control fluid connection or from the control fluid connection to the control fluid outlet.

[0028] In a preferred embodiment, it is provided that a pressure sensor, in particular an absolute pressure sensor, is arranged between the collection point and the control fluid connection, in particular between the mass flow sensor and the control fluid connection, where it is further preferred that the control unit is connected to the pressure sensor in terms of signaling.

[0029] The provision of a pressure sensor, and in particular its connection to the control unit in terms of signalling, has the advantage that the pressure of the control fluid can also be taken into account in the operation of the sensorless diaphragm pump.

[0030] Due to the volumetric coupling of the control fluid side chamber and the medium side chamber of the sensor-less diaphragm pump, not only is the volumetric flow rate and correspondingly the delivered volume of the delivered medium related to the control fluid, but also the pressure of the delivered medium. Since the delivered medium, and in particular its components such as biological cells, are often pressure-sensitive and / or can be adversely affected or destroyed by shear forces, it is advantageous to be able to take into account pressure, in particular, for example, predefined limit values, pressure ranges and / or pressure gradients, in particular time gradients, which are to be met in the control, in operation in order to achieve a particularly gentle delivery of the delivered medium by the sensor-less diaphragm pump.

[0031] Additionally, including the pressure of the control fluid further improves the accuracy of the operation of the sensorless diaphragm pump.

[0032] In a further embodiment, the control arrangement further comprises a temperature sensor and / or a temperature sensor interface for signal exchange with the temperature sensor, in particular for receiving signals from the temperature sensor, in which case the control unit is preferably connected in terms of signaling to the temperature sensor and / or the temperature sensor interface.

[0033] The temperature sensor may be configured to sense, for example, the temperature of the surroundings. Further, the temperature sensor may be configured to sense, for example, the temperature of the medium being conveyed in the bioreactor.

[0034] Sensing the temperature or using the signal of a temperature sensor contributes to a further improvement of the operation. Taking the temperature into account in determining the volume by the volume flow rate and the detected mass flow rate makes it possible in particular to further improve the accuracy of the operation.

[0035] Furthermore, in a further preferred embodiment it is provided that the control unit has a communication interface for exchanging data with an external communication unit, in particular it is preferred that the communication interface has or is a data interface for exchanging data.

[0036] Via the communication interface, for example, the desired control algorithm, the limit values, ranges or gradients that the pressure must meet, the flow rate, the mass flow rate or volume flow rate or the delivered and therefore predetermined volume, and / or the evaluations and / or values ​​generated during control can be transmitted to an external communication unit and further processed there.

[0037] In particular, it is desirable for the control unit to be configured to actuate a first proportional valve of the control arrangement to allow throughflow, deliver control fluid, and close the first proportional valve once the delivered volume has been achieved, and to actuate a second proportional valve to allow throughflow, deliver control fluid, and close the second proportional valve once the delivered volume has been achieved.

[0038] It is further desirable that the control unit is configured to determine the delivered volume of control fluid, and determining the delivered volume of control fluid desirably includes receiving a mass flow signal from the mass flow sensor, deriving a volumetric flow rate from the mass flow signal, and deriving the volume of control fluid delivered from the volumetric flow rate.

[0039] It is further preferred that the control unit is configured to determine an end position of the diaphragm of the sensor-less diaphragm pump, where determining the end position of the diaphragm of the sensor-less diaphragm pump preferably includes actuating the first and / or second proportional valve to deliver control fluid at a predetermined initial volumetric flow rate, receiving a pressure gradient signal, and establishing the presence of the diaphragm end position when the pressure gradient signal changes.

[0040] According to a further aspect of the invention, the object stated in the introduction is achieved by a diaphragm pump arrangement comprising a diaphragm pump, in particular a sensorless diaphragm pump, and comprising a control arrangement as described above.

[0041] According to a further aspect, the object stated in the introduction is achieved by a diaphragm pump for use with the control arrangement described above, the diaphragm pump being characterised in that it does not have a distance sensor for detecting the position of the diaphragm.

[0042] According to a further aspect, the object stated in the introduction is achieved by a bioreactor having a diaphragm pump arrangement as described above or comprising a diaphragm pump as described above.

[0043] According to a further aspect, the object stated in the introduction is achieved by the use of the above-mentioned diaphragm pump arrangement in a bioreactor or in a bioreactor with the above-mentioned diaphragm pump.

[0044] According to a further aspect, the objects stated in the introduction are realized by a method of controlling a sensorless diaphragm pump, the method comprising: actuating a first proportional valve of a control arrangement to allow throughflow, delivering a control fluid, and closing the first proportional valve when a delivered volume is achieved; actuating a second proportional valve to allow throughflow, delivering a control fluid, and closing the second proportional valve when a delivered volume is achieved.

[0045] The method described herein enables volumetric control of a sensorless diaphragm pump. To this end, control fluid is first delivered from a first control fluid reservoir to a control fluid connection, preferably at a predetermined mass flow rate and / or a predetermined volume flow rate, by corresponding actuation of a first proportional valve. Once the delivered volume is achieved, the first proportional valve is closed. To this end, the delivered volume of control fluid is preferably determined and compared to a desired delivered volume. Once the delivered volume is achieved and the first proportional valve is closed, a second proportional valve is actuated to achieve throughflow, and control fluid is delivered from the control fluid connection to a second control fluid reservoir, preferably at a predetermined mass flow rate and / or a predetermined volume flow rate. Once the delivered volume is achieved, the second proportional valve is closed. Again, the delivered volume of control fluid is preferably determined and compared to the desired delivered volume.

[0046] The delivery of control fluid by the first proportional valve and the delivery of control fluid by the second proportional valve are realized in different flow directions, towards the diaphragm pump in the former case and away from the diaphragm pump towards the second control fluid reservoir in the latter case.

[0047] Determining the delivered volume of control fluid preferably includes sensing a mass flow rate of the control fluid, deriving a volumetric flow rate from the mass flow rate, and deriving a volume of the delivered control fluid from the volumetric flow rate.

[0048] The detection of the mass flow rate of the control fluid is preferably achieved by a mass flow sensor in the control arrangement before the control fluid leaves the control fluid connection in the direction of the sensorless diaphragm pump. For the derivation of the volumetric flow rate from the mass flow rate, depending on the boundary conditions, an approximately isothermal process may be assumed in the case of low speeds, or a differential pressure or adiabatic process in the case of relatively fast changes.

[0049] The volumetric flow rate F of the gaseous control fluid may be determined based on, for example, a relationship based on the ideal gas equation or a function individually adapted to the gaseous fluid used, where the molar flow rate n, and, if possible, the sensed pressure p and / or the sensed temperature T and the universal gas constant R are preferably taken into account. For example, the following formula (1) may be used as the basis here: F=(n*R*T) / p (1)

[0050] To derive the volume of the control fluid conveyed, preferably the mass flow rate related to the molar flow rate is used to determine the number of molar particles by time integration, from which the volume of the control fluid conveyed through the control fluid connection can be determined with the aid of a relationship based on the ideal gas equation of state or a function individually fitted to the gas fluid, and possibly taking into account further parameters such as pressure and / or temperature.

[0051] From this, it is possible to derive the volume delivered inside the control fluid side chamber of the diaphragm pump, preferably taking into account a dead volume which preferably includes the volume of components arranged to guide the control fluid extending between the control fluid inlet of the control fluid side chamber of the sensorless diaphragm pump and the proportional valve of the control arrangement.

[0052] In a preferred development, the method further comprises sensing the pressure of the control fluid and actuating the first and / or second proportional valves such that a predetermined target pressure of the control fluid is not exceeded and / or such that a predetermined target pressure range is met and / or such that a predetermined pressure gradient is met.

[0053] The pressure of the control fluid is preferably determined by a pressure sensor of the control arrangement, in particular inside the control arrangement, before the control fluid flows out of the control fluid connection in the direction of the sensorless diaphragm pump. The operation of the sensorless diaphragm pump is preferably realized so that predetermined pressure parameters are met. In particular, a pressure gradient with respect to pressure changes over time should be met here, so as to realize a medium transport that is as gentle as possible for the cells.

[0054] A further preferred development of the method comprises determining the end positions of the diaphragm of the sensor-less diaphragm pump, whereby the volumetric end positions of the diaphragm of the sensor-less diaphragm pump are preferably detected, the volumetric end positions of the diaphragm corresponding in particular to the maximum and minimum filling volumes of the control fluid side chambers and the maximum and minimum filling volumes of the medium side chambers of the sensor-less diaphragm pump.

[0055] Locating along the diaphragm of a sensorless diaphragm pump preferably includes delivering a control fluid at a predetermined initial volumetric flow rate, sensing a pressure gradient of the control fluid, and establishing the presence of an end position of the diaphragm as the pressure gradient changes.

[0056] Herein, preferably, the control fluid is delivered, particularly at a predetermined initial volumetric flow rate, and the pressure gradient of the control fluid is detected in parallel until it is established that the pressure gradient is changing, particularly a significant increase. From this, it can be inferred that the diaphragm has reached one of its end positions. Preferably, by delivering the control fluid in the opposite direction, also at a predetermined initial volumetric flow rate, and by detecting the pressure gradient of the control fluid, the presence of a second end position of the diaphragm can be inferred from a significant change in the pressure gradient. The total differential volume of the sensorless diaphragm pump can be derived from the volumetric flow delivered between the two end positions. Correspondingly, a reference point of the diaphragm located between the two end positions and the associated delivered volume can also be identified. The neutral position of the diaphragm corresponds, for example, to half of the total differential volume.

[0057] The methods and developments thereof described herein have features and method steps that make them particularly suitable for use with the control arrangements and developments thereof connected herein.

[0058] The control arrangements and developments thereof described herein have features that make them particularly suitable for use with the methods and developments thereof described herein, or are correspondingly designed for this purpose.

[0059] With regard to the advantages of the aspects, the variations of the embodiments and the details of the embodiments, and their developments, described herein, reference is also made to the descriptions of the corresponding features and advantages of the respective other aspects.

[0060] Preferred exemplary embodiments will now be described, by way of example, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0061] [Figure 1] 1 is a schematic diagram of a diaphragm pump arrangement having a control arrangement and a sensorless diaphragm pump. [Figure 2] FIG. 1 is a schematic flow diagram of a method for controlling a sensorless diaphragm pump. DETAILED DESCRIPTION OF THE INVENTION

[0062] FIG. 1 shows a schematic diagram of a diaphragm pump arrangement 100 having a control arrangement 13 and a sensorless diaphragm pump 14, and FIG. 2 shows a schematic flow diagram of a method 1000 of controlling the sensorless diaphragm pump 14.

[0063] In the drawings, identical or substantially functionally identical elements are provided with the same reference numerals. The general description is in principle relevant to all embodiments unless differences are explicitly stated.

[0064] 1 shows a diaphragm pump arrangement 100 having a sensorless diaphragm pump 14 and having a control arrangement 13. Besides the diaphragm pump arrangement 100, first and second control fluid reservoirs 1A, 2A, a bioreactor 40, and a sample container 41 are shown.

[0065] The sensorless diaphragm pump 14 has an elastic diaphragm 15 that fluidly separates a control fluid side chamber 16 from a media side chamber 17 while volumetrically engaging the chambers. Through a control fluid inlet 18 of the diaphragm pump 14, a control fluid supplied by the control arrangement 13 through a control fluid line 10 can flow into and out of the interior of the control fluid side chamber 16 of the diaphragm pump 14. The media side chamber 17 of the diaphragm pump 14 has a media inlet 20 with an automatically actuated check valve 22 and a media outlet 19 with a similarly automatically actuated check valve 21. Through the media inlet 20 and the media outlet 19, a transported medium may be guided from a bioreactor 40 to the diaphragm pump 14 and from the diaphragm pump 14 to, for example, a sample container 41.

[0066] The sensor-less diaphragm pump 14 does not have a distance sensor for determining the position of the diaphragm 15. The sensor-less diaphragm pump 14 preferably does not have any additional sensors, which provides the advantage that the sensor-less diaphragm pump 14 is inexpensive to produce and may therefore be used as a disposable bioreactor pump, particularly in conjunction with a disposable bioreactor.

[0067] The control fluid required for the operation of the diaphragm pump 14 is provided through control fluid reservoirs 1A, 2A. The first control reservoir 1A serves as a compressed air supply and has a pressure level in the range of 200 to 10,000 hPa, which is increased relative to a reference pressure. The second control fluid reservoir serves as a vacuum system and has a pressure level in the range of -200 to -900 hPa, which is decreased relative to a reference pressure.

[0068] The control arrangement 13, the system boundary of which is indicated by a dashed line, preferably houses all components necessary for the volumetric actuation of the sensor-less diaphragm pump 14. In this way, the control capabilities housed in the control arrangement and the components necessary for this purpose may be arranged separately from the sensor-less diaphragm pump, and in particular spatially separated therefrom, so that, for example, the sensor arrangement 13 may be designed to be reusable and the sensor-less diaphragm pump 14 may be designed as a disposable component.

[0069] The control arrangement 13 has a control fluid inlet 1 for connection to a first control fluid reservoir 1A and a control fluid outlet 2 for connection to a second control fluid reservoir 2A. The control fluid inlet 1 and the control fluid outlet 2 are connected through a control fluid line to a collection point 6. The connection point 6 is further connected through a control fluid line to a control fluid connection 8. Through the control fluid inlet 8 the control arrangement 13 may be connected through a control fluid line to a control fluid inlet 18 of the diaphragm pump 14.

[0070] The control fluid inlet 1 is connected to a collection point 6 through a first proportional valve 3 and the control fluid outlet 2 is connected to a collection point 6 through a second proportional valve 4. The proportional valves 3, 4 are connected to a control unit 12 in terms of signaling.

[0071] A thermal mass flow sensor 5 and an absolute pressure sensor 7 are arranged between the collection point 6 and the control fluid connection 8. Both the mass flow sensor 5 and the pressure sensor 7 are connected in a signaling sense to the control unit 12. Furthermore, a temperature sensor 11 is provided which measures the ambient temperature and is connected in a signaling sense to the control unit 12 via a temperature sensor interface 13B. The control arrangement 13 further comprises a communication interface 13A which is particularly configured for exchanging data with an external communication unit. The communication interface 13A is preferably configured as a digital interface.

[0072] From the control fluid inlet 1, the control fluid is transported from the first control fluid reservoir 1A through the first proportional valve 3 to the collection point 6, from where it is passed through the control fluid connection 8 to the diaphragm pump 14, thereby filling the control fluid side chamber 16, and thus the medium placed in the medium side chamber 17 of the diaphragm pump 14 is discharged through the medium outlet 19 of the diaphragm pump 14 and supplied, for example, to a sample container 41.

[0073] Through the control fluid inlet 18, the control fluid is extracted from the control fluid side chamber 16 of the diaphragm pump 14 through the control fluid connection 8 and is pumped through the collection point 6 and the second proportional valve 4 through the control fluid outlet 2 into the second control fluid reservoir 2A.

[0074] The control fluid therefore flows in different flow directions in the control arrangement 13 between the collection point 6 and the control fluid connection 8 depending on the conveying direction. The mass flow sensor 5 is therefore preferably configured to sense the mass flow rate of the control fluid regardless of the flow direction, or to perform mass flow sensing in both the flow direction from the collection point 6 to the control fluid connection 8 and from the control fluid connection 8 to the collection point 6. The pressure sensor 7 is preferably similarly configured to sense the pressure of the control fluid regardless of the flow direction.

[0075] The mass flow sensor 5 is preferably in the form of a thermal mass flow sensor for gaseous media, the measurement signal of which is related to the molar flow rate of the gas.

[0076] The sensorless diaphragm pump 14 may be operated by the control arrangement 13 such that the conveyed medium in the medium side chamber 17 of the diaphragm pump moves from the medium inlet 20 to the medium outlet 19, and the flow of control fluid through the control fluid line 10 causes the diaphragm 15 to move in a manner volumetrically controlled by the control arrangement 13.

[0077] In particular, the control unit 12 of the control arrangement 13 is preferably configured to perform the method 1000 shown in FIG.

[0078] In the method 1000 for controlling the sensorless diaphragm pump 14, first, in step 1001, the first proportional valve 3 is actuated to achieve through-flow, and control fluid is delivered in the direction of the diaphragm pump 14. In step 1002, the first proportional valve 3 is closed as soon as the delivered volume is achieved. Subsequently, in step 1003, the second proportional valve 4 is actuated to achieve through-flow, and control fluid is delivered from the diaphragm pump 14 to the second control fluid reservoir 2A, and finally, in step 1004, the second proportional valve 4 is closed as soon as the delivered volume is achieved.

[0079] To establish that the volume delivered has been achieved, the actual delivered volume of the control fluid is preferably determined. This is preferably achieved as follows: The mass flow sensor 5 is used to determine the mass flow rate, which is related to the molar flow rate. In the case of a liquid control fluid, this is directly related to the volumetric flow rate. In the case of a gaseous control fluid with defined properties, for example, compressed air, the output signal of the thermal mass flow sensor 5 is preferably related to the molar flow rate of the control fluid. From this, the volumetric flow rate can be derived or calculated, taking into account the corresponding conditions, in particular the corresponding properties of the control fluid, and boundary parameters. For example, the volumetric flow rate of the control fluid can be calculated based on the ideal gas equation of state or a function-based relationship suited to the gaseous control fluid used, taking into account the molar flow rate determined by the mass flow sensor 5, the absolute pressure p measured by the pressure sensor 7, the temperature detected by the temperature sensor 11, and the universal gas constant. Here, in the case of low velocity and differential pressure, an approximately isothermal process or an adiabatic process can be used as the basis.

[0080] From the molar flow rate n determined by the mass flow sensor 5, the number of molar particles N can first be determined by time integration. Preferably, in a next step, this can be used to calculate the current volume V in the control fluid side chamber 16 of the diaphragm pump 14 and therefore the corresponding expelled volume of the medium being conveyed, by taking into account the ideal gas equation of state and the parameters measured by the pressure sensor 7 and the temperature sensor 11. The volume V thus determined is directly related to the volumetric displacement of the medium being conveyed.

[0081] Preferably, the method of controlling the sensorless diaphragm pump 14 further includes sensing the pressure of the control fluid and actuating the first and / or second proportional valves such that a predetermined target pressure of the control fluid is not exceeded and / or such that a predetermined target pressure range is met and / or such that a predetermined pressure gradient is met.

[0082] The difference in volume between a first position of the diaphragm 15 with an associated volume of the control fluid side chamber 16 and a second position of the diaphragm 15 with an associated second volume of the control fluid side chamber 16 may be referred to as the differential volume dV. When the first and second positions of the diaphragm are at their end positions, the result is the total differential volume. Initializing the integrator with a predefined initial value to calculate the number of particles to be considered is described below.

[0083] Here, volumetric control with a predetermined volumetric flow rate may proceed, for example, as follows: a conveyed volume dV of the conveyed medium is conveyed at a predetermined volumetric flow rate. For this purpose, control fluid is caused to flow in a regulated manner from the control fluid reservoir 1A into the control fluid side 16 of the diaphragm pump 14, the first proportional valve 3 is actuated by the control unit 12 as described above to specify the volumetric flow rate and the conveyed volume, so that the volumetric flow rate F is regulated by a predetermined value and the process is terminated after the conveyed volume dV is reached.

[0084] Subsequently, the second proportional valve 4 is actuated by the control unit 12 as described above to specify the volumetric flow rate and volume, such that the medium to be delivered is sucked into the medium side chamber 17 of the diaphragm pump 14 at the delivered volume dV and a predetermined volumetric flow rate F, and the control fluid is forced to flow out of the control fluid side 16 of the diaphragm pump 14 into the control fluid reservoir 2A, the volumetric flow rate being adjusted by the predetermined value, and the process is terminated after the delivered volume dV has been achieved.

[0085] Furthermore, it may be desirable to additionally monitor the pressure acting on the control fluid and, associated, on the conveyed medium, which not only has advantages with regard to the conveyed medium and its components (e.g., limitation of shear forces acting on biological cells and associated improved process reliability), but also in terms of increased plant safety and work safety. Here, the pressure and / or pressure gradient of the control fluid is limited to predefined limit values ​​by pressure measurement by pressure sensor 7 and appropriate intervention of control unit 12 at proportional valves 3, 4.

[0086] The inclusion of a pressure sensor makes it possible to achieve volume control at a predetermined pressure and / or pressure gradient. Such a control method may proceed as follows: First, through a regulated flow of control fluid from the control fluid reservoir 1A to the control fluid side chamber 16 of the diaphragm pump 14, the conveyed medium is discharged from the medium side chamber 17 of the diaphragm pump 14 at a conveyed volume dV and at a predetermined pressure profile, in particular a predetermined pressure profile over time. In this case, the first proportional valve 3 is actuated by the control unit 12, taking into account the detected absolute pressure p of the control fluid and the above-described method for determining the conveyed volume, so that the control fluid pressure p is regulated by a predetermined value and the process is terminated after the conveyed volume dV is reached. Subsequently, through a regulated flow of control fluid from the control fluid side chamber 16 of the diaphragm pump 14 to the control fluid reservoir 2A, the conveyed medium is sucked into the medium side chamber 17 of the diaphragm pump 14 at a conveyed volume dV and at a predetermined pressure profile, in particular a predetermined pressure profile over time. In this case, the proportional valve 4 is actuated by the control unit 12 using the sensed absolute pressure p and the above-described method for determining the delivered volume such that the control fluid pressure p is adjusted by design and the process is terminated after the delivered volume dV is achieved.

[0087] It is further possible for the volumetric end positions and intermediate reference points of the diaphragm 15 of the diaphragm pump 14 to be determined by the control arrangement 13. For this purpose, a predetermined low initial volumetric flow rate is first applied to the control fluid through the proportional valve 3, and the pressure sensor 7 continuously monitors the pressure temporal profile until its gradient becomes significantly steeper. In this way, it can be established that the diaphragm 15 of the diaphragm pump 14 has reached a mechanical stop position, i.e., a maximum or end position. After this method has been performed for a first end position through the flow of control fluid from the control fluid reservoir 1A to the control fluid side chamber 16 through the proportional valve 3, the method can also be started in the opposite direction, with the flow of control fluid from the control fluid side chamber 16 of the diaphragm pump 14 through the proportional valve 4 to the control fluid reservoir 2A at a predetermined initial volumetric flow rate. Here, too, the pressure sensor 7 simultaneously continuously monitors the pressure temporal profile, and a second end position is detected when the gradient increases significantly.

[0088] In an additional aspect, the total differential volume dVtotal is also preferably determined by the method described above, the total differential volume being obtained between the two end positions of the diaphragm 15 of the diaphragm pump 14. Based on this information, definition and operation is possible at any intermediate reference point of the diaphragm 15, for example the neutral position at half the total differential volume dVtotal.

[0089] To determine the initial volume, the dead volume formed by the sum of all volumes of the connected control fluid system elements from the two proportional valves 3, 4 to the diaphragm pump 14 at the end position of the diaphragm pump corresponding to the minimum volume of the control fluid side chamber 16 is preferably determined. This dead volume results from the design of the control arrangement and the control fluid lines connecting it to the diaphragm pump and is therefore easy to determine. For initialization, operation is realized for the corresponding end position of the diaphragm, and the starting value of the particle number N of the integrator is calculated based on the determined dead volume and the conditions currently measured by the pressure sensor 7 and the temperature sensor 11, taking into account a relationship based on the ideal gas equation or a function suitable for the control fluid used.

[0090] The control arrangement and method for controlling a sensorless diaphragm pump described herein have numerous advantages over existing solutions. Existing solutions rely, inter alia, on distance sensors to detect the position of the diaphragm of the diaphragm pump, which in principle are associated with larger tolerances because the displaced volume is only indirectly determined and the spatial deformation of the elastic diaphragm cannot be reproducibly accounted for. Furthermore, distance sensors for detecting the diaphragm position increase the cost of the diaphragm pump. Furthermore, they increase the user's handling effort and result in a system structure with a low level of integration. In contrast, the control arrangement and method for controlling a sensorless diaphragm pump described herein enable diaphragm position control based on volumetric determination, making it possible to avoid placing sensor components in the direct vicinity of the diaphragm pump. In this way, real or volumetric determination of the displaced fluid volume can be achieved, rather than simply measuring the diaphragm distance due to non-reproducible deformation. At the same time, a high level of integration is achieved because all sensors required for control can be housed in the control system (and a temperature sensor can be connected thereto via a temperature sensor interface). In contrast, the actuated diaphragm pump does not have a sensor. This results in a simpler construction and improved handling for the user, since no sensor is housed in the diaphragm pump, and the associated connecting cables and corresponding connection outlays between the sensor and the control arrangement of the diaphragm pump are also not required. The control described herein furthermore allows components of the transported medium, such as biological cells, to be loaded or this load to be controlled only to a small extent. Overall, significant improvements can be realized in the operation of diaphragm pumps, especially in the application area of ​​disposable bioreactors in bioprocessing.

Claims

1. A control arrangement (13) for controlling a sensorless diaphragm pump (14), comprising: The control arrangement (13) a control fluid inlet (1) for connection to a first control fluid reservoir (1A) having an elevated pressure level relative to a reference pressure; a control fluid outlet (2) for connection to a second control fluid reservoir (2A) having a reduced pressure level with respect to a reference pressure; a control fluid connection (8) for connection of a control fluid line for said sensorless diaphragm pump (14); Equipped with The control fluid inlet (1) is connected to a collection point (6) through a first proportional valve (3) and the control fluid outlet (2) is connected to the collection point (6) through a second proportional valve (4); a mass flow sensor (5) located between said collection point (6) and said control fluid connection (8); The control arrangement (13) further comprises a control unit (12) connected in terms of signaling to the first proportional valve (3), the second proportional valve (4) and the mass flow sensor (5).

2. 2. The control arrangement (13) according to claim 1, wherein a pressure sensor (7), in particular an absolute pressure sensor, is arranged between the collection point (6) and the control fluid connection (8).

3. 3. The control arrangement (13) according to claim 1 or 2, further comprising a temperature sensor (11) and / or a temperature sensor interface (13B) for signal exchange with the temperature sensor, in particular for receiving signals from the temperature sensor.

4. 4. The control arrangement (13) according to any one of claims 1 to 3, wherein the control unit (12) is connected in terms of signaling to a pressure sensor (7) and / or a temperature sensor (11) and / or a temperature sensor interface (13B).

5. 5. The control arrangement (13) according to any one of claims 1 to 4, wherein the control unit (12) has a communication interface (13A) for exchange with an external communication unit.

6. A diaphragm pump arrangement (100) comprising a diaphragm pump (14), in particular a sensorless diaphragm pump (14), and comprising a control arrangement (13) according to any one of claims 1 to 5.

7. A diaphragm pump (14) for use with a control arrangement (13) according to any one of claims 1 to 5, comprising: The diaphragm pump (14) does not have a distance sensor for detecting the position of the diaphragm (15).

8. A bioreactor (40) comprising a diaphragm pump arrangement (100) according to claim 6 or comprising a diaphragm pump (14) according to claim 7.

9. Use of a diaphragm pump arrangement (100) according to claim 6 with a bioreactor (40) or with a diaphragm pump (14) according to claim 7 in a bioreactor.

10. A method (1000) for controlling a sensorless diaphragm pump (14), the method comprising: activating (1001) a first proportional valve of the control arrangement (13) to achieve throughflow and delivering a control fluid; closing the first proportional valve (1002) once the delivered volume is achieved; activating (1003) a second proportional valve to achieve throughflow and delivering said control fluid; closing the second proportional valve once the delivered volume is achieved (1004); A method (1000) comprising:

11. 11. The method (1000) of claim 10, comprising determining a delivered volume of the control fluid.

12. Determining the delivered volume of the control fluid comprises: sensing a mass flow rate of the control fluid; deriving a volumetric flow rate from the mass flow rate; deriving the delivered volume of the control fluid from the volumetric flow rate; 12. The method (1000) of claim 10 or 11, comprising:

13. sensing the pressure of the control fluid; operating the first proportional valve and / or the second proportional valve (3, 4) so ​​that a predetermined target pressure of the control fluid is not exceeded and / or a predetermined target pressure range is met and / or a predetermined pressure gradient is met; 13. The method (1000) of any one of claims 10 to 12, comprising:

14. 14. The method (1000) of any one of claims 10 to 13, comprising determining an end position of a diaphragm (15) of the sensorless diaphragm pump (14).

15. Identifying the end position of the diaphragm (15) of the sensorless diaphragm pump (14) comprises: delivering the control fluid at a predetermined initial volumetric flow rate; sensing a pressure gradient of the control fluid; Establishing the presence of an end position of the diaphragm (15) when the pressure gradient changes.

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