The present invention relates to a micromembrane pumping device for pumping a fluid. Micromembrane pumping devices are known, for example, from documents AU 2015308144 A1 and US 20160153444 A1.
According to an embodiment, a micromembrane pumping device for pumping a fluid may have: a pump chamber to which an inlet valve for introducing the fluid into the pump chamber, an outlet valve for discharging the fluid from the pump chamber, and a membrane device for varying a volume of the pump chamber are associated, the membrane device having a plate-shaped actuator for deforming the membrane device; and influencing means for influencing the plate-shaped actuator so as to influence the volume of the pump chamber; wherein the membrane device has a plate-shaped membrane body limiting the pump chamber; wherein the plate-shaped actuator is arranged on a side of the plate-shaped membrane body facing away from the pump chamber; wherein the plate-shaped actuator is mounted to the plate-shaped membrane body by means of an electrically insulating glue layer such that the plate-shaped actuator is electrically insulated from the membrane body; wherein at least one embedded portion of a support body at which or in which a deformation sensor for detecting a deformation of the membrane device is arranged, is arranged within the electrically insulating glue layer so as to detect the volume of the pump chamber; wherein the influencing means, the plate-shaped actuator and the deformation sensor form a closed loop control loop for regulating a ratio between a change in volume of the pump chamber during an operating cycle of the micromembrane pumping device and a duration of the operating cycle of the micromembrane pumping device.
The fluid to be pumped may be a liquid or a gas. The pump chamber is a closed cavity into which the respective fluid is introduced via an inlet valve and from which the respective fluid is discharged via an outlet valve. The inlet valve and the outlet valve may each be passive valves.
The membrane device is part of a housing which surrounds the pump chamber and is deformable elastically such that the volume of the pump chamber changes such that, when the volume increases, the fluid is sucked into the pump chamber and, when the volume decreases, the fluid is ejected from the pump chamber. By periodically increasing and decreasing the volume of the pump chamber, a defined volume flow of the fluid can be caused.
In order to cause such changes in volume of the pump chamber, the membrane device comprises a plate-shaped actuator configured for deforming the membrane device such that the volume of the pump chamber changes. The plate-shaped actuator advantageously is an electrically operated actuator.
A plate-shaped implementation of a body in this case means that the body comprises a considerably smaller dimension in one spatial direction than in the other two spatial directions. The actuator may be implemented to be round or polygonal in top view.
Additionally, influencing means is provided, which influences the plate-shaped actuator so as to influence the desired change in volume of the pump chamber. The influencing means may be electrical influencing means which generates electrical signals fed to the actuator in order to influence the same.
The membrane device comprises an elastically deformable membrane body which limits the pump chamber and is implemented to be plate-shaped. The membrane body may, for example, be mounted to a frame or holder of the housing. However, it may also be implemented to be integrated with other parts of the housing.
The plate-shaped actuator is arranged on a side of the plate-shaped membrane body facing away from the pump chamber. This means that it is not in direct contact to the fluid to be pumped, which particularly makes transmitting electrical signals from the influencing means to the actuator easier.
Thus, the plate-shaped actuator is mounted to the plate-shaped membrane body by means of an electrically insulating glue layer. The glue layer here is configured for transmitting forces from the actuator to the membrane body so as to allow deformation of the membrane body and, thus, a change in volume of the pump chamber. The electrically insulating implementation of the glue layer causes the plate-shaped actuator to be electrically insulated from the membrane body. This means that it is possible to use a plate-shaped actuator which is supplied electrically, irrespective of ground, on its side facing the membrane body, even if the membrane body is electrically conducting.
The actuator can comprise a height between 30 μm and 2000 μm, in particular between 45 μm and 1500 μm so as to ensure the necessary forces. It is to exhibit high rigidity, good adhering characteristics, resistance to environmental influences (humidity, solvents, temperature, radiation (which is frequently used in medical apparatuses for sterilization purposes)). Additionally, it is to be resistant to breaking, resistant to fatigue and electrically resistant to breakdown.
The electrically insulating implementation of the glue layer is also of advantage when the membrane body is implemented to be electrically insulating, since in this case an electrical field strength between the actuator and the fluid to be pumped is decreased so that electrical arcing between the actuator and the fluid can be prevented. This is of particular advantage when the plate-shaped actuator is operated at higher electrical voltages, for example in a range between 20 V and 400 V.
The glue layer is to be formed as thin as possible on both sides of the embedded portion of the support body. It is to exhibit high rigidity, good adhering characteristics, resistance to environmental influences (humidity, solvents, temperature, radiation (which is frequently used in medical apparatuses for sterilization purposes)). Additionally, it is to be resistant to breaking, resistant to fatigue, non-conducting and electrically resistant to breakdown.
Within the electrically insulating glue layer, there is an embedded portion of a support body at the surface of which or within which a deformation sensor is arranged which can detect the volume of the pump chamber over time by detecting a deformation of the membrane device.
The embedded portion of the support body may be thinner than 500 μm so as to ensure the necessary flexibility. It is to exhibit high rigidity, good adhering characteristics, resistance to environmental influences (humidity, solvents, temperature, radiation (which is frequently used in medical apparatuses for sterilization purposes)). Additionally, it is to be resistant to breaking, resistant to fatigue, non-conducting and electrically resistant to breakdown.
The influencing means, the plate-shaped actuator and the deformation sensor here form a closed loop control circuit for regulating the ratio, caused by the micromembrane pumping device, between a change in volume of the pump chamber (2) during an operating cycle of the micromembrane pumping device (1) and a duration of the operating cycle of the fluid.
A closed-loop control circuit generally means a self-contained loop for influencing a physical quantity in a technical process or other system. The direct or indirect feedback of the current value of the controlled variable to the regulator, which counteracts a deviation from a set value (negative feedback), is the essential point here. The object of the regulator is adjusting disturbance quantities and determining the time behavior of the controlled variable relative to the static and dynamic behavior in accordance with predetermined requirements.
In the present invention, the influencing means performs the task of a regulator. The controlled variable here is the ratio between the change in volume of the pump chamber during an operating cycle of the micromembrane pumping device and a duration of the operating cycle. The operating cycle comprises a phase in which the fluid is introduced into the pump chamber via the inlet valve, and another phase in which the fluid is discharged via the outlet valve. In disturbance-free operation, this ratio corresponds to the volume flow of the respective fluid. The volume flow is measured indirectly from knowing the duration of the operating cycle, which is predetermined by the influencing means, and from knowing the deformation of the membrane device detected by means of the deformation sensor.
The indirect measurements are transmitted to influencing means so that, in the case of a deviation of the volume flow from a set value, driving the plate-shaped actuator can be changed so as to result in the desired volume flow. In particular, the volume flow can be influenced by increasing or decreasing the amplitude of the change in volume of the pump chamber. Also, a frequency of the change in volume of the pump chamber can be increased or decreased.
It has been shown that such an indirect measurement of the volume flow is considerably faster and more precise, and also easier and cheaper than a direct measurement of the volume flow using well-known flow rate sensors which exemplarily comprise an impeller so that disturbance quantities can be adjusted considerably better. Additionally, the suggested micromembrane pumping device is superior to such pumping devices in which individual disturbance quantities, like temperature and pressures, are detected by sensors and used in an open-loop control circuit of the pumping device.
The volume flow can be controlled considerably more precisely using the suggested control circuit than is the case when using unregulated control means. Using a deformation sensor and its arrangement in the glue layer between the membrane body and the actuator allows highly precise feedback of the real value of the volume flow to the influencing means.
Thus, external influences, also referred to as disturbance quantities, on the volume flow can be adjusted precisely. Disturbance quantities which can be adjusted by the inventive micromembrane pumping device are:
The inventive micromembrane pumping device can be employed advantageously whenever highly precise dosing of a fluid is used, for example when mixing different fluids. In particular, it may be used in the medical field for dosing pharmaceuticals or for mixing components of pharmaceuticals.
In accordance with a further development of the invention, the glue layer is applied over an area, in particular the entire area, on a side of the plate-shaped actuator facing the membrane body, and/or the glue layer is applied over an area, in particular the entire area, on a side of the membrane body facing the plate-shaped actuator. In this way, forces generated by the actuator can be transmitted safely to the glue layer and from the glue layer to the membrane body. The result is, in particular, high rigidity of the arrangement and insensitivity towards high shear forces, which finally serves for dosing precision.
In accordance with a practical further development of the invention, the glue layer comprises cured liquid glue, cured gluing paste and/or adhesive film. Liquid glue, gluing pastes and adhesive films are easy to handle when manufacturing the membrane pumping device and exhibit sufficiently good adhering characteristics in order to securely transmit the required forces from the actuator to the membrane body, thereby increasing dosing precision.
In accordance with a further development of the invention, the glue layer comprises a temperature-curing material, an anaerobically curing material, a UV radiation-curing material, an activator-curing material, humidity-curing material, dry-curing material and/or hot-melt glue material. Such glue materials are easy to handle when manufacturing the membrane pumping device and exhibit sufficiently good adhering characteristics in order to securely transmit the required forces from the actuator to the membrane body, thereby increasing dosing precision.
In accordance with an advantageous further development of the invention, the plate-shaped actuator is an electromagnetic actuator, a single-layer or multi-layer piezoelectric actuator, a shape-memory actuator or a bimetal actuator. Single-layer piezoelectric actuators comprise an electrical terminal at their bottom and an electrical terminal at the top. Since, for the invention, the glue layer is non-conductive, the single-layer piezoelectric actuator may be fed symmetrically to ground. In the case of multi-layers, the two electrical contacts are arranged on that side facing the membrane body, thereby preventing short-circuiting the non-conducting characteristics of the glue layer. Shape-memory actuators or bimetal actuators can easily be used due to the insulating characteristics of the glue layer.
In accordance with a practical further development of the invention, the support body comprises one or more electrically insulating materials. Polyimides, for example, are particularly suitable.
In accordance with a practical further development of the invention, the support body comprises glass, one or more semiconductor materials, one or more composites, one or more polymeric materials or one or more ceramic materials.
In accordance with an advantageous further development of the invention, the deformation sensor is a strain gauge, in particular a resistive, capacitive or piezoresistive strain gauge.
In accordance with a practical further development of the invention, the deformation sensor is a force sensor.
In accordance with a practical further development of the invention, the membrane body comprises a metal, semiconductor material and/or plastic.
In accordance with a practical further development of the invention, at least a part of evaluation electronics for evaluating signals of the deformation sensor is arranged at or in the support body. The disturbance resistance can be improved by this, which finally increases dosing precision.
In accordance with a further development of the invention, the influencing means is implemented for recognizing operating disturbances of the micromembrane pumping device using measuring signals of the deformation sensor. During operation of the micromembrane pumping device, operating disturbances may occur. For example, the inlet valve or the outlet valve may be blocked by particles, the actuator may fail, an air bubble may reach the pump chamber in the case of a liquid fluid, and the like. Such disturbances are recognizable in the measuring signals of the deformation sensor since they influence the deformation of the membrane means or directly influence the actuator.
In accordance with a practical further development of the invention, the support body comprises a non-embedded portion which is led out from the glue layer, wherein contacts for tapping measuring signals of the deformation sensor which are electrically connected to the deformation sensor are attached to the non-embedded portion. The electrical connections between the contacts for the deformation sensor and the deformation sensor thus may be implemented at or in the support body so that these are mechanically protected and electrically insulated from both the actuator and the membrane body.
In accordance with a practical further development of the invention, a heating wire is arranged at or in the embedded portion. The heating wire allows heating the fluid to be pumped. Additionally, the heating wire may be used during manufacturing of the micromembrane pumping device for heating the glue layer, for curing the same in case the glue layer comprises a temperature-curing material. A heating wire here may be provided with electrical energy by the influencing means or by external means.
In accordance with a practical further development of the invention, the support body comprises a non-embedded portion which is led out from the glue layer, wherein contacts for providing the heating wire with electrical energy which are electrically connected to the heating wire, are attached to the non-embedded portion. The electrical connections between the contacts for the heating wire and the heating wire may be formed at or in the support body so that these are mechanically protected and electrically insulated from both the actuator and the membrane body.
In accordance with a practical further development of the invention, a temperature sensor is arranged at or in the embedded portion. Measuring signals of the temperature sensor may be fed, for example, to the influencing means or external means which provides the heating wire with electrical energy. In this way, the heating effect of the heating wire can be regulated during manufacturing the micromembrane pumping device or during operation of the micromembrane pumping device.
In accordance with a practical further development of the invention, the support body comprises a non-embedded portion which is led out from the glue layer, wherein contacts for tapping measuring signals of the temperature sensor which are electrically connected to the temperature sensor, are attached to the non-embedded portion. The electrical connections between the contacts for the temperature sensor and the temperature sensor can be formed at or in the support body so that these are mechanically protected and electrically insulated from both the actuator and the membrane body.
In accordance with an advantageous further development of the invention, a state sensor, in particular a humidity sensor or a chemical sensor, for checking a state of the glue layer is arranged at or in the embedded portion. The measuring signals of the state sensor may be fed to the influencing means. In this way, the influencing means can recognize an age-induced deterioration of the state of the glue layer, or deterioration caused by internal influence, before the glue layer fails which is of advantage in particular in medical applications.
In accordance with an advantageous further development of the invention, the support body comprises a non-embedded portion which is led out from the glue layer, wherein contacts for tapping measuring signals of the state sensor which are electrically connected to the state sensor are attached to the non-embedded portion. The electrical connections between the contacts for the state sensor and the state sensor may be formed at or in the support body so that these are mechanically protected and electrically insulated from both the actuator and the membrane body.
In accordance with a practical further development of the invention, the embedded portion of the support body, when viewed in a direction from the plate-shaped actuator towards the plate-shaped membrane body, comprises an area smaller than an area of the plate-shaped membrane body facing the embedded portion of the support body, and smaller than an area of the plate-shaped actuator facing the embedded portion of the support body. In this way, it can be ensured that the glue layer is at least partly continuous from the actuator to the membrane body in the indicated direction. The result is a particularly good force transmission between the actuator and the membrane body.
In accordance with an advantageous further development of the invention, the embedded portion of the support body comprises at least one through hole which extends from a side of the embedded portion of the support body, facing the plate-shaped actuator, to a side of the embedded portion of the support body facing the plate-shaped membrane body. This causes the glue layer to extend without interruption from the actuator to the membrane body in the region of the through hole in the direction from the actuator towards the membrane body. The result is a particularly good force transmission between the actuator and the membrane body.
In accordance with a practical further development of the invention, the embedded portion of the support body, when viewed in a direction from the plate-shaped actuator towards the plate-shaped membrane body, comprises an edge comprising recesses. The glue layer extends without interruptions from the actuator to the membrane body in the region of the recesses. Since a large part of the forces generated by the actuator is transmitted on the glue layer in an edge region of the actuator, the result is a particularly good force transmission from the actuator to the membrane body.
Embodiment of the present invention and its advantages will be described in greater detail below referring to the figures, in which:
Same or uniform elements or elements of equal or equivalent function will subsequently be provided with same or uniform reference numerals.
In the following description, embodiments having a plurality of features of the present invention will be described in more detail so as to provide better understanding of the invention. However, it is to be stated that the present invention may also be realized while omitting certain of the described features. It is also to be pointed out that the features shown in different embodiments may also be combined differently, provided this is not excluded explicitly or would result in contradictions.
The micromembrane pumping device 1 for pumping a fluid FL comprises:
a pump chamber 2 to which an inlet valve 3 for introducing the fluid FL into the pump chamber 2, an outlet valve 4 for discharging the fluid FL from the pump chamber 2, and a membrane device 5 for varying a volume of the pump chamber 1 are associated, wherein the membrane device 5 comprises a plate-shaped actuator 6 for deforming the membrane device 5; and
influencing means 7 for influencing the plate-shaped actuator 6 so as to influence the volume of the pump chamber 2;
wherein the membrane device 5 comprises a plate-shaped membrane body 8 limiting the pump chamber 2;
wherein the plate-shaped actuator 6 is arranged on a side of the plate-shaped membrane body 8 facing away from the pump chamber 2;
wherein the plate-shaped actuator 6 is mounted to the plate-shaped membrane body 8 by means of an electrically insulating glue layer 9 so that the plate-shaped actuator 6 is electrically insulated from the membrane body 8;
wherein at least one embedded portion 10 of a support body 11 at which or in which a deformation sensor 12 for detecting a deformation of the membrane device 5 is arranged, is arranged within the electrically insulating glue layer 9 in order to detect the volume of the pump chamber 2;
wherein the influencing means 7, the plate-shaped actuator 6 and the deformation sensor 12 form a closed-loop control circuit for regulating a ratio between a change in volume of the pump chamber (2) during an operating cycle of the micromembrane pumping device (1) and a duration of the operating cycle of the micromembrane pumping device 1.
In accordance with a further development of the invention, the glue layer 9 is applied over an area, in particular the entire area, on a side of the plate-shaped actuator 6 facing the membrane body 8 and/or the glue layer 9 is applied over an area, in particular the entire area, on a side of the membrane body 8 facing the plate-shaped actuator 6.
According to an advantageous further development of the invention, the glue layer 9 comprises a cured liquid glue, a cured gluing paste and/or adhesive film.
In accordance with an advantageous development of the invention, the glue layer 9 comprises a temperature-curing material, an anaerobically curing material, a UV radiation-curing material, an activator-curing material, a humidity-curing material, a dry-curing material and/or a hot-melt glue material.
In accordance with a practical further development of the invention, the plate-shaped actuator 6 is an electromagnetic actuator, a single-layer or multi-layer piezoelectric actuator, a shape-memory actuator or a bimetal actuator.
In accordance with an advantageous further development of the invention, the support body 11 comprises one or more electrically insulating materials.
In accordance with a practical further development of the invention, the support body 11 comprises glass, one or more semiconductor materials, one or more composites, one or more polymeric materials or one or more ceramic materials.
According to an advantageous further development of the invention, the deformation sensor 12 is a strain gauge, in particular a resistive, capacitive or piezoresistive strain gauge.
According to a practical further development of the invention, the deformation sensor 12 is a force sensor.
In accordance with a practical further development of the invention, the membrane body 8 comprises a metal, semiconductor material and/or plastic.
In accordance with a practical further development of the invention, at least a part of evaluation electronics for evaluating signals of the deformation sensor 12 is arranged at or in the support body 11.
In accordance with a practical further development of the invention, the influencing means 7 is configured for recognizing operating disturbances of the micromembrane pumping device 1 using measuring signals MS of the deformation sensor 12.
In accordance with a practical further development of the invention, the support body 11 comprises a non-embedded portion 13 which is led out from the glue layer 9, wherein contacts 14 for tapping measuring signals MS of the deformation sensor which are electrically connected to the deformation sensor are attached to the non-embedded portion 13.
In the embodiment of
In accordance with a further development of the invention, a heating wire 17 is arranged at or in the embedded portion 10.
According to an advantageous further development of the invention, the support body 11 comprises a non-embedded portion 13 which is led out from the glue layer 9, wherein contacts 18 for providing the heating wire 17 with electrical energy EE which are electrically connected to the heating wire 17 are attached to the non-embedded portion 13.
According to an advantageous further development of the invention, a temperature sensor 20 is arranged at or in the embedded portion 10.
In accordance with a practical further development of the invention, the support body 11 comprises a non-embedded portion 13 which is led out from the glue layer 9, wherein contacts 21 for tapping measuring signals TMS of the temperature sensor 20 which are electrically connected to the temperature sensor 20 are attached to the non-embedded portion 13.
In the embodiment of
Additionally, the temperature sensor 20 is connected to contacts 21 formed at the non-embedded portion 13 of the support body 11. The contacts 21 are connected to the influencing means 7 via a measuring line 22 so that measuring signals TMS of the temperature sensor 20 can be transmitted to the influencing means 7. The measuring signals TMS can be used by the influencing means 7 to regulate the heat power of the heating wire 17.
According to an advantageous further development of the invention, a state sensor 23, in particular a humidity sensor or a chemical sensor, for checking a state of the glue layer 9 is arranged at or in the embedded portion 10.
According to a practical further development of the invention, the support body 11 comprises a non-embedded portion 13 which is led out from the glue layer 9, wherein contacts 24 for tapping measuring signals ZMS of the state sensor 23 which are electrically connected to the state sensor 23 are attached to the non-embedded portion 13.
In the embodiment of
In accordance with an advantageous further development of the invention, the embedded portion 10 of the support body 11, when viewed in a direction RI from the plate-shaped actuator 6 towards the plate-shaped membrane body 8, comprises an area 26 which is smaller than an area 27 of the plate-shaped membrane body 8 which faces the embedded portion 10 of the support body 11, and which is smaller than an area 28 of the plate-shaped actuator 6 which faces the embedded portion 10 of the support body 11.
In accordance with a practical further development of the invention, the embedded portion 10 of the support body 11 comprises at least one through hole 29 which extends from a side of the embedded portion 10 of the support body 11 facing the plate-shaped actuator 6 to a side of the embedded portion 10 of the support body 11 facing the plate-shaped membrane body 8.
In accordance with an advantageous further development of the invention, the embedded portion 10 of the support body 11, when viewed in the direction RI from the plate-shaped actuator 6 towards the plate-shaped membrane body 8, comprises an edge 30 which comprises recesses 31.
The volume flow of the fluid FL can be generated by periodically moving the actuator 6 back and forth between the position shown in
While this invention has been described in terms of several embodiments, there are alterations, permutations, and equivalents which will be apparent to others skilled in the art and which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.
This application is a continuation of copending International Application No. PCT/EP2020/066821, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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Parent | PCT/EP2020/066821 | Jun 2020 | US |
Child | 18067370 | US |