EP4689396A1

EP4689396A1 - Micropump and method for pumping fluid

Info

Publication number: EP4689396A1
Application number: EP24715818.1A
Authority: EP
Inventors: En-Te Hwu; Anja Boisen
Original assignee: Danmarks Tekniske Universitet
Current assignee: Danmarks Tekniske Universitet
Priority date: 2023-04-04
Filing date: 2024-04-03
Publication date: 2026-02-11
Also published as: WO2024208872A1

Abstract

The present disclosure relates to a micropump comprising: a fluid section comprising: a pumping cavity; an inlet; an outlet; a diaphragm; and an actuator section comprising: a coil; a plurality of magnets arranged at an end of the coil; an armature at least partly arranged in the coil, extending into a space between the plurality of magnets, further protruding from the space between the plurality of magnets, wherein the armature is configured to deflect between the plurality of magnets when an alternating magnetic field is generated by the coil; at least one drive rod attached to the armature and to the diaphragm, wherein the micropump is configured to draw a fluid into the fluid section via the inlet and discharge the fluid via the outlet when the drive rod causes the diaphragm to oscillate. The disclosure further relates to a method for pumping a fluid.

Description

Micropump and method for pumping fluid

The present disclosure relates to a micropump having a pumping cavity and an actuator comprising a coil, magnets and a drive rod for driving a diaphragm of the pumping cavity to pump a fluid. The disclosure further relates to a method for pumping a fluid.

Background

Micropumps are devices that can control and manipulate small fluid volumes. The size and improved dosing accuracy make micropumps attractive for a range for applications, such as drug delivery, including, for example, insulin or glucose for diabetes patients, transportation of blood, wound therapy, administration of neurotransmitters to neurons, chemical/biological sensing etc.

Miniaturized mechanical micropumps mostly use diaphragm mechanism that are mainly driven by piezoelectric actuators. A diaphragm micropump uses the repeated actuation of a diaphragm to drive a fluid. Driving mechanisms include, for example, electrostatic actuation, piezoelectric actuation and thermal actuation. Piezoelectric driven micropumps rely on electromechanical property of piezo ceramic to deform in response to applied voltage. A piezoelectric disk attached to the membrane causes diaphragm deflection driven by the external axial electric field thus expanding and contracting the chamber of the micropump.

Despite progress being made in the field, the existing micropumps are still associated with technical challenges related to accuracy, performance, cost, reliability and size. A number of parameters, such as pressure, temperature, piezo actuator fatigue or physical constraints, may have an influence on the performance of the micropump. In particular, most available devices need to have a certain minimum size and driving voltage to provide the required flow.

MEMS (micro-electromechanical system) piezoelectric micropumps offer an alternative to standard pumps that have traditionally been used in precision controlled drug delivery devices. These MEMS pumps are, however, manufactured by an expensive clean room process. Moreover, the flow rate is proportional to the diameter of the piezoelectric actuator. Thus, the MEMS pumps may typically be relatively large. Summary

It is an object of the present disclosure to provide a micropump that overcomes some of the disadvantages of the known micropumps. According to a first embodiment, a micropump is provided, which comprises: a fluid section comprising: a pumping cavity for admitting and discharging fluid; an inlet; an outlet; a diaphragm; and an actuator section comprising: a coil; a plurality of magnets arranged at an end of the coil; an armature at least partly arranged in the coil, extending into a space between the plurality of magnets, further protruding from the space between the plurality of magnets, wherein the armature is configured to deflect between the plurality of magnets when an alternating magnetic field is generated by the coil; at least one drive rod attached to the armature and to the diaphragm, wherein the micropump is configured to draw a fluid into the fluid section via the inlet and discharge the fluid via the outlet when the drive rod causes the diaphragm to oscillate.

The micropump may be seen as an armature-driven micropump. A first embodiment of the micropump is shown in fig. 1. The micropump is based on a technical concept corresponding to a balanced armature driver. In the embodiment shown in fig. 1 the actuator section has a coil and two magnets arranged at an end of the coil. When an alternating current is generated in the coil it generates an alternating magnetic field, which causes the armature, which comprises a magnetic material, to oscillate between the two magnets. This will cause the drive rod, which is connected to both the armature and the diaphragm, to oscillate the diaphragm in the same frequency. Preferably, no magnets or coils are attached to the diaphragm.

The absence of coils or magnets attached on the oscillating diaphragm allows the diaphragm of the disclosed micropump to reach very high resonance frequencies, which translates into higher and completely controllable pump rates. The lack of excess weight on the diaphragm due to the absence of attached magnets or coils allows the drive rod to cause high frequency oscillations on the diaphragm.

The presently disclosed armature-driven micropump can provide several advantages, including high performance, high energy efficiency, small size, low manufacturing cost and easily integrable on circuit boards.

The micropump may be adapted to pump a liquid, such as water, a drug or a chemical fluid, or a gas, such as air or a chemical gas.

The pumping cavity, as well as the inlet and outlet, may be implemented in various ways. Typically, the inlet may comprise a one-way valve configured to allow a flow of a fluid only towards the inside of the pumping cavity, whereas the outlet may comprise a one-way valve configured to allow a flow of a fluid only away from the inside of the pumping cavity.

The present disclosure further relates to a method for pumping a fluid, comprising the steps of: providing a micropump comprising: a fluid section comprising: a pumping cavity for admitting and discharging fluid; an inlet; an outlet; a diaphragm; an actuator section comprising: a coil; a plurality of magnets arranged at an end of the coil; an armature at least partly arranged in the coil, extending into a space between the plurality of magnets, further protruding from the space between the plurality of magnets, wherein the armature is configured to deflect between the plurality of magnets when an alternating magnetic field is generated by the coil; at least one drive rod attached to the armature and to the diaphragm, generating an oscillating electric current to the coil to induce an oscillating movement of the armature, causing the diaphragm to vibrate to move fluid from the inlet to the outlet through the pumping cavity.

These and other aspects of the invention are set forth in the following detailed description if the invention.

Description of the drawings

Various embodiments are described hereinafter with reference to the drawings. The drawings are examples of embodiments and are intended to illustrate some of the features of the presently disclosed micropump and method for pumping a fluid, and are not limiting to the presently disclosed micropump and method.

Fig. 1 shows an embodiment of the micropump.

Fig. 2 shows an alternative embodiment of the micropump with external valves.

Fig. 3 shows a further view of an embodiment of the micropump with one-way valves. Fig. 4-7 show examples of inlet/outlet configurations.

Fig. 8 shows an embodiment of the micropump comprising a micro controller and a flow sensor.

Fig. 9 shows a flow chart of a method according to an embodiment of the presently disclosed method for pumping a fluid.

Fig. 10 show examples of performance of two embodiments of the micropump.

Detailed description

The present disclosure relates to a micropump. The micropump comprises a fluid section and an actuator section. The fluid section comprises a pumping cavity, an inlet, an outlet and a diaphragm. The diaphragm may form a wall of the fluid section. When the diaphragm is deflected outwardly from the pumping cavity, fluid is pulled into the pumping cavity through the inlet. When the diaphragm is deflected inwardly to the pumping cavity, fluid is pushed out from the pumping cavity through the outlet. This process may be repeated at a high frequency to pump fluid substantially continuously. The actuator section comprises a coil, a plurality of magnets arranged at an end of the coil, an armature at least partly arranged in the coil and configured to move between the magnets when an alternating magnetic field is generated by the coil, and at least one drive rod. Preferably, a first end of the at least one drive rod is attached to the armature and a second end attached to the diaphragm. In this configured the micropump will draw a fluid into the fluid section via the inlet and discharge the fluid via the outlet when the drive rod causes the diaphragm to oscillate.

A coil within the context of the present disclosure shall be construed broadly to cover any suitable electromagnet that can produce a magnetic flux in the armature that can be used to move the armature back and forth, preferably be deflecting, between the magnets. As the armature vibrates, these vibrations are transmitted to the diaphragm via the drive rod attached. The lack of excess weight on the diaphragm due to the absence of attached magnets or coils allows the drive rod to cause high frequency oscillations on the diaphragm.

The presently disclosed micropump can be used in a number of applications, including, but not limited to, microbiome acquisition, drug delivery, for example, transdermal insulin dosing, glucose injection, anti-thrombogenic blood transportation, administration of neurotransmitters, negative pressure wound therapy, nasal aspirator pump, electronic nose, smartwatch blood pressure monitoring, air monitoring, smart helmet cooling, gas sensor and micro fuel cell. Wearable medical devices (smart watch/ring/band/skin patches for blood pressure/insulin dosing/etc.) can effectively reduce the cost of the healthcare system, workload of medical personnel, increase the precision of disease diagnostics/drug delivery and patients’ quality of life. The micropump may be used in smart pills to collect samples. It may also be used for air quality measurements in, for example, buildings. Further possible applications are chemical and biochemical analysis, environmental monitoring, in satellite microthrusters and micropropulsion systems, portable cooling systems, fuel cells, inkjet printing, industrial automation and irrigation systems.

The pumping cavity, as well as the inlet and outlet, may be implemented in various ways. In one example, shown in fig. 1 , the inlet and the diaphragm are on opposite sides of the pumping cavity. In this embodiment the outlet is on one of the sides. An alternative embodiment is shown in fig. 2, wherein the pumping cavity 103 has a main compartment 103a and an additional compartment 103b in which the inlet and the outlet are disposed. The inlet and outlet may be disposed at opposite sides of the pumping cavity. The inlet may comprise a one-way valve configured to allow a flow of a fluid only towards the inside of the pumping cavity. The outlet may comprise a one-way valve configured to allow a flow of a fluid only away from the inside of the pumping cavity. This configuration of valves may serve the purpose of maintaining the proper flow of the fluid, flowing into the pumping cavity through the inlet and out from the pumping cavity through the outlet. The one-way valves may be, for example, 3D printed or injection molded. The one-way valves may be made of plastic or metal.

Fig. 3 shows a further view of an embodiment of the micropump with examples of oneway valves. The one-way valves in figs. 3A and 3B are external one-way valves, which have been 3D printed.

The presently disclosed micropump may further comprise an inlet tube and an outlet tube, wherein each of the inlet tube and outlet tube comprises an inline one-way valve arranged inside the inlet tube and the outlet tube, respectively. As stated, the inlet may comprise a one-way valve configured to allow a flow of a fluid only towards the inside of the pumping cavity. The outlet may comprise a one-way valve configured to allow a flow of a fluid only out from the inside of the pumping cavity. In case the micropump comprises an inlet tube and/or an outlet tube connected to the pumping cavity, a oneway valve may be arranged or integrated into the inlet tube and/or another one-way valve may be arranged or integrated into the outlet tube. The inline one-way valves may have a first body comprising a movable membrane suspended by a structure, such as a flexure structure, and a second body comprising a corresponding opening covered by the movable membrane. Preferably, the movable membrane can only be moved in one direction from a closed position, which makes the inline valve a one-way valve. Preferably, the inline one-way valve of the inlet tube only allows fluid to flow towards the pumping cavity, and the inline one-way valve of the outlet tube only allows fluid to flow out from the pumping cavity. The flexure structure may be a flexible element that can be arranged with some freedom in the inlet and outlet tubes. Both the first body part and the second body part may have tubular outer shapes that fit inside the inlet tube and outlet tube. Fig. 6A and 6B show an example of inline one-way valves. An inlet tube 115 and an outlet tube 116 are connected to a main body of the micropump. The inlet 101 comprises an inline one-way valve 117, which has a first body 118 and a second body 120. The movable membrane and the opening in the second body part are not visible for the inlet 101 but function in the same way as for the outlet 102. The outlet 102 comprises an inline one-way valve 117, which has a first body 118 and a second body 120. The first body 118 comprises an opening 121. The second body 120 comprises a corresponding movable membrane 119. Fig. 6A further includes detailed views of examples of the first body 118 and the second body 120. It can be noted that the first body 118 is arranged on the side where fluid flows from, whereas the second body 120 is arranged on the side to which the fluid flows. The first body 118 comprises an opening 121 and a sealing ring 124. The second body comprises a movable membrane 119 and a flexible structure 124 that holds the movable membrane 119. When fluid pushes the movable membrane 119 from the inside above a certain predefined pressure, the flexible structure 124 and the movable membrane 119 allow the fluid to flow through the one-way valve. Fig. 6C shows an example of inline duckbill valves 117. A duckbill valve is a type of check valve that allows fluid to flow in only one direction. When fluid flows in the desired direction, the valve opens, and the flow pushed against the walls of the valve, allowing it to flex and permit passage. Duckbill valves are typically made of an elastomeric material.

Fig. 7 shows a further solution, which uses a membrane-less valve. The inlet of the membrane-less valve may comprise a diffuser. An inlet diffuser is a component that is used to slow down and diffuse the flow of the fluid entering the pumping cavity. The diffuser may comprise a diverging section of a duct that gradually increases in cross- sectional area. This may help smoothening out turbulence or fluctuations in the incoming fluid.

The diffuser may comprise a body having a truncated conical shape, defined by a minor base of smaller radius, a major base of larger radius and a curved lateral surface connecting the minor base and the major base. The major base of the inlet may be oriented towards the pumping section. The minor base of the diffuser may be oriented away from the pumping section.

Any suitable valve(s) may be used for allowing fluid to pass into the pumping cavity via the inlet and allowing fluid to exit the pumping cavity via the outlet. In addition to the above mentioned valves, it would be possible to use, for example, any type of suitable check valve and/or ball valve and/or heart valve.

The outlet may comprise a nozzle. A nozzle is a component that controls the direction and speed of a fluid as it flows through the outlet. The design of the nozzle typically involves a converging section that narrows the path of the fluid, followed by a diverging section that widens the flow path again.

A first embodiment of the micropump 100 is shown as a cross-sectional view in fig. 1. The micropump 100 according to this embodiment has a fluid section 108, which comprises an inlet 101 and an outlet 102. A liquid enters the pumping cavity 103 through the inlet 101 and exits the pumping cavity 103 through the outlet 102. The micropump 100 further comprises an actuator section 109, which comprises a coil 106 and a plurality of magnets 107. The plurality of magnets 107 are arranged at an end of the coil 106. An armature 104 is disposed in the coil 106 and extends into a space between the magnets 107. The armature 104 further extends through the space between the magnets 107. An end of the armature protrudes from the space between the magnets 107. The end of the armature is connected to a drive rod 105. The armature 104 in the example of fig. 1 is substantially U-shaped. A “U” can generally be described as a shape having two straight “arms” and a curved bottom part. In the embodiment of fig. 1 one of the arms extends centrally through the coil 106. The other arm is preferably rigidly fixed to a fixed part of the micropump, such as to the magnet house 114 or to the housing of the micropump 100. A drive rod 105 is connected to the armature 104 and to the diaphragm 110. The two magnets 107, more precisely the parts of the magnets 107 facing the space between them. When an AC current is applied to the coil 106 it will cause variations of magnetic flux in the armature 104. These variations will make the part of the armature 104 located in the space between the magnets 107 to deflect back and forth between the magnets 107 in an oscillating movement. The oscillating movement is transferred from the end of the armature 104 to the diaphragm 110 through the drive rod 105.

In one embodiment the armature has a U shape wherein at least one part of the U is located in the coil and in the space between the plurality of magnets.

The presently disclosed micropump may comprise a flow sensor, such as a micro- electro-mechanical system (MEMS) microphone flow sensor device.

A MEMS microphone flow sensor works by measuring the changes in pressure and airflow. The sensor may be based on a small diaphragm that vibrates when it is exposed to fluid waves or changes in fluid flow. The vibrations of the diaphragm are detected by a sensor, such as a capacitive, that measures the movement of a micro beam moved by the fluid flow as the diaphragm moves.

The flow sensor may be connected to a micro controller, which can process the measured signal to determine the flow rate of the fluid being measured. A MEMS microphone flow sensor is highly sensitive and can detect even small changes in airflow or pressure.

The micro controller may also be configured to control a current in the coil, which can be used to regulate the flow of fluid produced by the micropump. A micro controller within the context of the present disclosure, shall be construed broadly to include any processing unit suitable for controlling the flow of fluid produced by the micropump. Such a processing unit can also be used for reading and/or interpreting measured signals from a flow sensor in the micropump or receiving other measurements or external control signals.

Fig 8. shows a further embodiment of a micropump 100. The micropump 100 according to this embodiment has a fluid section 108, which comprises an inlet 101 and an outlet 102. A liquid enters the pumping cavity 103 through the inlet 101 and exits the pumping cavity 103 through the outlet 102. The micropump 100 further comprises an actuator section 109, which comprises a coil 106 and a plurality of magnets 107. The plurality of magnets 107 are arranged at an end of the coil 106. An armature 104 is disposed in the coil 106 and extends into a space between the magnets 107. The armature 104 further extends through the space between the magnets 107. An end of the armature protrudes from the space between the magnets 107. The end of the armature is connected to a drive rod 105. The armature 104 in the example of fig. 1 is substantially U-shaped. A “U” can generally be described as a shape having two straight “arms” and a curved bottom part. In the embodiment of fig. 1 one of the arms is arranged in the coil 106. A drive rod 105 is connected to the armature 104 and to the diaphragm 110. The micropump 100 further comprises a flow sensor 111 and a microcontroller 112. The micropump 100 further comprises a current generator 113. The micro controller 112, which may be provided as any suitable processing unit, may be used for various tasks, such as controlling the alternating electric current to the coil 106 and/or interpreting measured signals from the flow sensor 111. The flow sensor 111 may be any suitable flow sensor. In the specific example of fig. 8, the flow sensor includes flow sensor circuitry 122 and a microbeam 123. Microbeam-based flow sensor utilize the principle of fluid-induced deflection of beams to measure a flow rate. A flow rate can be calculated based on the deflection of the beam.

By generating an alternating current in the coil, a corresponding alternating magnetic field is generated. The alternating current may have a frequency of at least 1 Hz, preferably at least 100 Hz or at least 1000 Hz. In one embodiment the alternating current has a frequency between 50 and 150 Hz. The coil may accordingly provide an alternating magnetic field based on an alternating electric current. Accordingly, the alternating magnetic field may have a frequency of at least 1 Hz, preferably at least 100 Hz or at least 1000 Hz. In one embodiment the alternating magnetic field has a frequency between 50 and 150 Hz.

As a non-limiting example and reference, a micropump operating in the order of 1 kHz may have a flow rate of at least 20 pl/s, preferably, at least 30 pl/s, more preferably at least 100 pl/s.

The micropump may operate at low voltages, such as a voltage less than 5V, preferably less than 3V, more preferably less than 2V. The micropump may be configured to operate without a voltage amplifier.

The micropump may be configured to generate the alternating current in any suitable waveform, such as a triangular wave, square wave, sine wave or a combination.

The presently disclosed micropump can be said to be built on the principles of a speaker, wherein the diaphragm, which in the case of a speaker produces a sound, is instead utilized to drive the flow of the fluid in the pumping cavity. The micropump can thereby be made very small and efficient. As an example, a micropump having dimension of less than 5x2x2 mm can be used to obtain a pumping capacity of more than 2 ml/minute.

The armature may comprise a magnetic material, such as a ferromagnetic material, such as iron, steel, nickel or cobalt. The plurality of magnets arranged in the coil may be permanent magnets. A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. The two magnets, more precisely the parts of the magnets facing the space between them, may be oppositely charged. The two magnets may have substantially flat surfaces towards the space between them.

The diaphragm may comprise a distal surface and a proximal surface, wherein the proximal surface is in contact with the fluid in the pumping cavity. The diaphragm may constitute at least a part of a sidewall of the pumping cavity. The diaphragm may separate the fluid section from the actuator section and may provide a fluid-tight barrier. The diaphragm may comprise a waterproof material, such as rubber, plastic, metal, or a polymer-based material, such as polyethylene terephthalate, polyetheretherketone, or polyimide.

The at least one drive rod may extend longitudinally along a central axis from the armature to the diaphragm. The drive rod may have a cross-sectional shape, such as a circle or a polygon. Preferably, it has a rigid structure. The drive rod may have one end attached to a central point of the diaphragm. Alternatively, or in combination, one end of the at least one drive rod may be attached to a peripheral point of the diaphragm.

Fig. 9 shows a flow chart of an embodiment of a method 200 for pumping a fluid. The method 200 comprises the steps of: providing a micropump (201); and generating an oscillating electric current to the coil to induce an oscillating movement of the armature, causing the diaphragm to vibrate to move fluid from the inlet to the outlet through the pumping cavity (202).

A person skilled in the art will recognize that the presently disclosed method for pumping a fluid may use any embodiment of the presently disclosed micropump and vice versa.

Fig. 10 show examples of performance of two embodiments of the micropump. While the embodiments can be further optimized - the presently disclosed micropump is not limited to any of the parameters of these examples of configurations - the data can give indications of what the micropump can achieve.

Fig. 10A shows the obtained flow rates for a number of different AC current frequencies used for generating the alternating magnetic field. The pumping cavity in this example is 13.2 mm³ and the input voltage is 3.0 V, alternating. As can be seen the micropump can achieve a flow rate of 6.828 pL/s at 800 Hz in this configuration.

Fig. 10B shows the obtained flow rates for a number of different AC current frequencies used for generating the alternating magnetic field. The pumping cavity in this example is 88.1 mm³ and the input voltage is 3.0 V, alternating. As can be seen the micropump can achieve a flow rate of 26 pL/s at 75 Hz in this configuration.

List of elements in figures

100 - micropump

101 - inlet 102 - outlet

103 - pumping cavity

104 - armature

105 - drive rod

106 - coil

107 - magnet

108 - fluid section

109 - actuator section

110 - diaphragm

111 - flow sensor

112 - micro controller/processing unit

113 - current generator

114 - magnet housing

115 - inlet tube

116 - outlet tube

117 - one-way valve

118 - first body

119 - movable membrane

120 - second body

121 - opening

122 - flow sensor circuitry

123 - microbeam

124 - sealing ring

125 - flexible structure

Further details

1. A micropump comprising: a fluid section comprising: a pumping cavity for admitting and discharging fluid; an inlet; an outlet; a diaphragm; and an actuator section comprising: a coil; a plurality of magnets arranged at an end of the coil; an armature at least partly arranged in the coil, extending into a space between the plurality of magnets, further protruding from the space between the plurality of magnets, wherein the armature is configured to deflect between the plurality of magnets when an alternating magnetic field is generated by the coil; at least one drive rod attached to the armature and to the diaphragm, wherein the micropump is configured to draw a fluid into the fluid section via the inlet and discharge the fluid via the outlet when the drive rod causes the diaphragm to oscillate.

2. The micropump according to item 1 , wherein the inlet and outlet are disposed at opposite sides of the pumping cavity.

3. The micropump according to any one of the preceding items, wherein the drive rod is connected to a protruding end of the armature.

4. The micropump according to any one of the preceding items, comprising an inlet tube and an outlet tube, wherein each of the inlet tube and outlet tube comprises an inline one-way valve arranged inside the inlet tube and the outlet tube, respectively.

5. The micropump according to item 4, wherein the inline one-way valve has a first body comprising a movable membrane suspended by a structure, such as a flexure structure and a second body comprising a corresponding opening covered by the movable membrane.

6. The micropump according to any one of items 4-5, wherein the inline one-way valve of the inlet tube only allows fluid to flow towards the pumping cavity, and wherein the inline one-way valve of the outlet tube only allows fluid to flow out from the pumping cavity.

7. The micropump according to any one of the preceding items, wherein the inlet comprises a one-way valve configured to allow a flow of a fluid only towards the inside of the pumping cavity. 8. The micropump according to any one of the preceding items, wherein the outlet comprises a one-way valve configured to allow a flow of a fluid only away from the inside of the pumping cavity.

9. The micropump according to any one of the preceding items, wherein the coil is configured to generate a controllable alternating magnetic field based on an alternating electric current.

10. The micropump according to any one of the preceding items, wherein the alternating magnetic field has a frequency of at least 1 Hz, preferably at least 100 Hz or at least 1000 Hz.

11. The micropump according to any one of the preceding items, wherein the armature has a II shape wherein at least one arm of the II extends centrally through a coil tunnel of the coil.

12. The micropump according to item 11, wherein a second arm of the armature is rigidly fixed to a fixed part of the micropump.

13. The micropump according to any one of the preceding items, wherein the armature comprises a magnetic material, such as a ferromagnetic material.

14. The micropump according to any one of the preceding items, wherein the diaphragm comprises a distal surface and a proximal surface, wherein the proximal surface is in contact with the fluid in the pumping cavity.

15. The micropump according to any one of the preceding items, wherein the diaphragm separates the fluid section from the actuator section.

16. The micropump according to any one of the preceding items, wherein the diaphragm constitutes a fluid-tight barrier.

17. The micropump according to any one of the preceding items, wherein the diaphragm comprises a waterproof material, such as rubber, plastic, metal, polytetrafluoroetylen, or a polymer-based material, such as polyethylene terephthalate, polyetheretherketone, or polyimide. The micropump according to any one of the preceding items, wherein the at least one drive rod extends longitudinally along a central axis and comprises a cross-sectional shape such as a circle or a polygon. The micropump according to any one of the preceding items, wherein one end of the at least one drive rod is attached to a central point of the diaphragm. The micropump according to any one of the preceding items, wherein one end of the at least one drive rod is attached to a peripheral point of the diaphragm. The micropump according to any one of the preceding items, wherein the fluid is a liquid, such as water, a drug or a chemical fluid, or wherein the fluid is a gas, such as air or a chemical gas. The micropump according to any one of the preceding items, wherein the pumping cavity comprises a flow sensor, such as a MEMS microphone flow sensor device. The micropump according to any one of the preceding items, wherein the micropump further comprises a micro controller configured to control a current in the coil. The micropump according to any one of the preceding items, wherein the inlet comprises a diffuser. The micropump according to item 24, wherein the diffuser comprises a body having a truncated conical shape, defined by a minor base of smaller radius, a major base of larger radius and a curved lateral surface connecting the minor base and the major base. The micropump according to item 25, wherein the major base of the inlet is oriented towards the pumping section. The micropump according to any one of items 25-26, wherein the minor base of the diffuser is oriented away from the pumping section. The micropump according to any one of the preceding items, wherein the outlet comprises a nozzle. A method for pumping a fluid, comprising the steps of: providing a micropump comprising: a fluid section comprising: a pumping cavity for admitting and discharging fluid; an inlet; an outlet; a diaphragm; an actuator section comprising: a coil; a plurality of magnets arranged at an end of the coil; an armature at least partly arranged in the coil, extending into a space between the plurality of magnets, further protruding from the space between the plurality of magnets, wherein the armature is configured to deflect between the plurality of magnets when an alternating magnetic field is generated by the coil; at least one drive rod attached to the armature and to the diaphragm, generating an oscillating electric current to the coil to induce an oscillating movement of the armature, causing the diaphragm to vibrate to move fluid from the inlet to the outlet through the pumping cavity.

Claims

2. The micropump according to claim 1, wherein the inlet and outlet are disposed at opposite sides of the pumping cavity.

3. The micropump according to any one of the preceding claims, wherein the drive rod is connected to a protruding end of the armature.

4. The micropump according to any one of the preceding claims, comprising an inlet tube and an outlet tube, wherein each of the inlet tube and outlet tube comprises an inline one-way valve arranged inside the inlet tube and the outlet tube, respectively.

5. The micropump according to claim 4, wherein the inline one-way valve has a first body comprising a movable membrane suspended by a structure, such as a flexure structure and a second body comprising a corresponding opening covered by the movable membrane.

6. The micropump according to any one of claims 4-6, wherein the inline one-way valve of the inlet tube only allows fluid to flow towards the pumping cavity, and wherein the inline one-way valve of the outlet tube only allows fluid to flow out from the pumping cavity.

7. The micropump according to any one of the preceding claims, wherein the inlet comprises a one-way valve configured to allow a flow of a fluid only towards the inside of the pumping cavity.

8. The micropump according to any one of the preceding claims, wherein the outlet comprises a one-way valve configured to allow a flow of a fluid only away from the inside of the pumping cavity.

9. The micropump according to any one of the preceding claims, wherein the coil is configured to generate a controllable alternating magnetic field based on an alternating electric current.

10. The micropump according to any one of the preceding claims, wherein the armature has a II shape wherein at least one arm of the II extends centrally through a coil tunnel of the coil.

11. The micropump according to claim 10, wherein a second arm of the armature is rigidly fixed to a fixed part of the micropump.

12. The micropump according to any one of the preceding claims, wherein the armature comprises a magnetic material, such as a ferromagnetic material.

13. The micropump according to any one of the preceding claims, wherein the diaphragm constitutes a fluid-tight barrier.

14. The micropump according to any one of the preceding claims, wherein the pumping cavity comprises a flow sensor, such as a MEMS microphone flow sensor device.

15. A method for pumping a fluid, comprising the steps of: providing a micropump comprising: a fluid section comprising: a pumping cavity for admitting and discharging fluid; an inlet; an outlet; a diaphragm; an actuator section comprising: a coil; a plurality of magnets arranged at an end of the coil; an armature at least partly arranged in the coil, extending into a space between the plurality of magnets, further protruding from the space between the plurality of magnets, wherein the armature is configured to deflect between the plurality of magnets when an alternating magnetic field is generated by the coil; at least one drive rod attached to the armature and to the diaphragm, generating an oscillating electric current to the coil to induce an oscillating movement of the armature, causing the diaphragm to vibrate to move fluid from the inlet to the outlet through the pumping cavity.