Microvalves and microvalve arrays

Abstract

Microvalves and microvalve arrays are provided that efficiently control fluid flow, conserve energy, and preferably operate noiselessly. The present disclosure relates to microvalves designed according to the present disclosure and microvalve arrays comprising one or more such microvalves, the microvalve comprising: a substrate having a cavity and at least one first opening and at least one second opening, each opening extending into the cavity; a flexible membrane separating the cavity into a first chamber and a second chamber; and an actuation element supported by the substrate, in contact with the flexible membrane, and operable to deflect the membrane to move it between at least two positions, the flexible membrane having at least one through hole extending between the first and second chambers.

Description

[Technical Field]

[0001] The present disclosure relates to microvalves designed in accordance with the present disclosure and to microvalve arrays comprising one or more such microvalves. [Background technology]

[0002] Microvalves are known to control the flow of fluids, such as gases and liquids, in many applications ranging from the aerospace, automotive, lab-on-a-chip, and oil industries to pharmaceutical, diagnostic, and medical applications. For example, in medical applications, microvalves may be part of pump systems for dosing and dispensing small amounts of fluid, and in the automotive industry they may be used to provide hydraulic control within comfort seating systems.

[0003] It is also known to provide a controlled flow of gas to inflate and deflate an array of inflatable air cushions. Such air cushions are used, for example, to adjust the contours of automobile seats, aircraft seats, etc., to suit the needs of the user. For example, these air cushions may be attached to a seat suspension. By filling or emptying the air cushions, the curvature can be changed to suit the front of the seat. By varying the filling of the upper or lower cushions, the curvature can be moved up or down. In addition, an array of cushions can be used to provide various massage functions for the passenger.

[0004] Additionally, it is known to provide a controlled gas flow to apply pressure, or alternating underpressure and overpressure, to an outlet. Such outlets may be used in biological applications, for example, to apply alternating pressure to cell membranes or cell cultures in microplates, such as 96-well plates. However, this application requires the use of multiple valves, and therefore, it is essential that each of these valves is particularly effective, energy-efficient, and noise-free.

[0005] As a result, there is a need for microvalves that efficiently control fluid flow, conserve energy, and preferably operate noiselessly.

[0006] The present disclosure is based on the idea of ​​providing a microvalve preferably having a buckling membrane provided with at least one through-hole, hereinafter also referred to as a perforated membrane, the through-hole also being referred to as a hole, aperture, window or passage. Summary of the Invention

[0007] In particular, a microvalve according to the present disclosure comprises a substrate having a cavity and at least one first opening and at least one second opening, each opening extending into the cavity; a flexible membrane separating the cavity into a first chamber and a second chamber; and an actuation element supported by the substrate, in contact with the flexible membrane, and operable to deflect the membrane to move it between at least two positions, the flexible membrane having at least one through hole extending between the first and second chambers.

[0008] It should be noted that according to the present disclosure, the flexible membrane and actuation element together may also be referred to as an actuator operable to open and close at least one aperture.

[0009] One advantage of providing the membrane with at least one through-hole is that pressure is partially compensated on both sides of the actuator. The actuator can therefore operate against a higher range of pressures or require less actuation energy to close against a certain pressure. Furthermore, particularly space-saving shapes can be realized.

[0010] Furthermore, because fluid can flow through the membrane, the microvalve can be constructed with an inlet located on one side of the membrane and an outlet located on the other side. Such a configuration is advantageous for controlling flow along a fluid path, such as a tube. In a particularly advantageous embodiment, at least one first opening is positioned to extend into the first chamber and a second opening is positioned to extend into the second chamber.

[0011] According to a further advantageous example, a valve seat is provided in at least one of the at least one first opening and the at least one second opening, and the flexible membrane is operable to contact the valve seat to close each of the at least one first opening and / or the at least one second opening in one of the positions. Providing a valve seat improves the leak-tightness of the closed valve. Furthermore, if the valve seat forms a convex portion extending toward the membrane, the required membrane deflection is reduced. The valve seat may be made of a rigid material, but is preferably made of an elastic, compressible material such as silicone. However, it should be noted that the membrane can close an opening even if the valve seat is not disposed around the opening. Furthermore, the valve seat may be attached to the surface of the membrane.

[0012] In particular, when the membrane is arranged in such a way that not only is pressure compensation achieved by the perforated membrane but also a fluid path passes over the membrane, it is advantageous for at least one through-hole to be arranged so that it remains unblocked in all positions.

[0013] As mentioned above, instead of simply bending, the membrane is advantageously a membrane that is deflected by buckling or a combination of bending and buckling, both of which are referred to as buckling.

[0014] To actuate such a membrane, the actuation element may comprise at least one ring-shaped piezoelectric drive element, the flexible membrane being operable to buckle upon actuation of the piezoelectric drive element. The use of a buckling membrane actuated by a ring-shaped piezoelectric drive element has the advantage that the membrane can be deflected over a much longer distance using the same energy compared to known bending actuation elements. The piezoelectric drive element does not need to be perforated, as only the periphery of the membrane needs to be subjected to a compressive force to buckle the membrane. Therefore, the mechanical properties of the actuation element are not affected by the perforations.

[0015] To facilitate the buckling movement of the membrane, the piezoelectric drive element may be supported around a peripheral region so that it can move, for example, the piezoelectric drive element may be held between two resilient bearings, such as O-rings or similar supports.

[0016] According to a further advantageous embodiment, these flexible and / or elastic supports can be compressed within a certain range while maintaining their flexibility and thus allowing movement of the actuator. This allows for continuous support throughout the entire range of actuation. Additionally, this flexibility range can be utilized during the assembly process by shifting the initial position of the actuator within the device, thereby adjusting, for example, the size of the valve opening gap.

[0017] This ability to move the actuator by compressing the flexible ring without affecting its behavior can also be used to compensate for manufacturing and / or assembly tolerances, whether they arise from surface roughness, tilt, tolerances, thermal contraction and expansion, part aging, or any other form of imperfection. The flexible support of the actuator can compensate for these imperfections, for example, by creating a more uniform support and sealing surface, which can provide the required geometric, mechanical, and fluid properties.

[0018] Additionally, the ability to move the actuator during assembly, thereby adjusting the opening clearance of the valve, can be used to calibrate the valve for required performance, such as flow rate, pressure, or response time. For example, calibrating the valve to have a larger initial clearance can increase the final allowable flow rate of the valve, whereas calibrating the valve to have a smaller clearance can increase the pressure tolerance of the valve.

[0019] According to a further advantageous embodiment, at least one through-hole is located in an area outside the center of the flexible membrane that is not covered by the piezoelectric actuator. This configuration advantageously allows for controlled fluid flow between two opposing openings and ensures maximum efficiency, since the opening to be closed can be located at the point of maximum membrane deflection. Additionally, both sides of the actuator are advantageously exposed to pressure, which reduces the net pressure the actuator must operate against. Therefore, using the same energy, the valve can operate against a higher pressure.

[0020] Additionally, pressure compensation across the actuator facilitates proportional operation of the valve. Unlike switching valves, which only provide a final open or closed state, proportional valves can provide intermediate states, thus controlling the final outlet flow rate of the valve under the same applied pressure, for example. This enables a wide range of applications, such as applying uniform pressure to cell cultures, counteracting fluctuating boundary conditions, or delivering a specific flow rate / pressure according to a control signal.

[0021] The pressure compensation along with the flexible support of the elastic ring during a wide range of operation and the combination of bending and buckling can improve the proportionality of the valve in various aspects such as accuracy, control and operating range.

[0022] To precisely control the buckling movement of the membrane, the actuation element may include a first piezoelectric drive element and a second piezoelectric drive element, and the flexible membrane is supported between the first and second piezoelectric drive elements. Depending on the applied mechanical force, the membrane can be deflected in two directions. Due to the perforations, particularly fast buckling movements are possible.

[0023] According to a further advantageous example of the present disclosure, two first openings extend into the first chamber and one second opening extends into the second chamber, the second openings preferably being disposed opposite one of the first openings, and valve seats are provided at the second opening and the opposite first opening, each valve seat being contactable by a flexible membrane. In this way, a 3 / 2-way valve can be realized using only one actuator. As is commonly known, an x / y-way valve (x and y are integers greater than 3) represents a valve assembly with x ports and y states.

[0024] Advantageously, in this configuration, pressure is partially compensated on both sides of the actuator. Thus, the actuator can operate against a higher range of pressures or require less actuation energy to close against a certain pressure. Depending on the pressure required and the pressure built up at each port, various configurations of the three ports can be realized for optimal performance.

[0025] As discussed above, microvalves according to the present disclosure may be advantageously used as part of an array to control the distribution of fluids, e.g., air. One advantage of using one or more microvalves according to the present disclosure can be seen in the efficient, precise, and nearly noiseless operation of the microvalves. One or more microvalves may be arranged side-by-side, i.e., as an array of microvalves substantially in one plane. Alternatively or additionally, some or all of the microvalves may be arranged as a stack.

[0026] By varying the number of actuators and providing different interconnections between the various openings in the substrate, various valve assemblies can be realized, such as a 5 / 2 valve or a 3 / 3 valve. A valve assembly having two or more flexible membranes with built-in interconnections is hereinafter referred to as a manifold. An assembly of two or more microvalves is also referred to as a microvalve array.

[0027] According to an advantageous example, the microvalve array may include at least a first microvalve and a second microvalve, the first microvalve and the second microvalve being interconnected by a fluid path connected to their respective first openings, which can be closed by movement of their respective flexible membranes. Thus, a 5 / 2-way valve assembly can be realized. Two microvalves can also be arranged in a stack to realize a compact 5 / 2 valve with a small footprint.

[0028] Particularly efficient control of fluid flow can be achieved using an extremely small profile when the first microvalve and the second microvalve each have two second openings and the flexible membrane of each of the first and second microvalves is capable of moving to close either its respective first opening or the second opening located opposite the first opening.

[0029] Furthermore, to achieve a 3 / 3 valve assembly, the microvalve array may include at least two microvalves interconnected by fluid paths connected to their respective second openings, the second openings being unable to be closed by movement of their respective flexible membranes.

[0030] For some applications, the microvalve array may additionally comprise at least one microvalve having a flexible membrane without through-holes.

[0031] The accompanying drawings are incorporated into and form a part of the specification to illustrate several embodiments of the present invention. These drawings, together with the detailed description, serve to explain the principles of the present invention. The drawings are merely for the purpose of illustrating preferred and alternative examples of how the invention can be made and used, and should not be construed as limiting the invention to the embodiments shown and described. Furthermore, several aspects of the embodiments may form solutions in accordance with the present invention, individually or in different combinations. Thus, the embodiments described below can be considered alone or in any combination. Further features and advantages will become apparent from the following detailed description of various embodiments of the present invention, as illustrated in the accompanying drawings, in which like reference numerals refer to like elements. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is a schematic cross-sectional view of a microvalve in a first state. [Figure 2] 2 is a schematic cross-sectional view of the microvalve of FIG. 1 in a second state. [Figure 3] FIG. 2 is a schematic cross-sectional view of a further microvalve in a first state; [Figure 4] 4 is a schematic cross-sectional view of the microvalve of FIG. 3 in a second state. [Figure 5] 1 is a schematic cross-sectional view of a microvalve manifold in a first state. [Figure 6] FIG. 6 is a schematic cross-sectional view of the microvalve manifold of FIG. 5 in a second state. [Figure 7] FIG. 10 is a schematic cross-sectional view of a further microvalve manifold in a first state; [Figure 8] FIG. 8 is a schematic cross-sectional view of the microvalve manifold of FIG. 7 in a second state. [Figure 9] FIG. 8 is a schematic cross-sectional view of the microvalve manifold of FIG. 7 in a third state. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention will now be described in detail with reference to the drawings, with initial reference to Figure 1, which shows in schematic cross-section a first example of a microvalve 100 representing a 2 / 2-way valve, i.e., a microvalve having two ports and two states. It should be noted that in all figures of this disclosure, dimensions are not drawn to scale, and in particular heights are often exaggerated compared to lateral dimensions in order to more clearly illustrate geometric principles.

[0034] The microvalve 100 has a substrate 102 having a cavity 104 formed therein. A first opening 106 and a second opening 108 extend into the cavity 104 and allow a fluid flow 110 to enter and exit the cavity 104. As mentioned above, the fluid may be a gas, such as air, or any liquid. The openings 106, 108 are also referred to as ports.

[0035] To control fluid flow 110, microvalve 100 includes an actuator 112. According to the present disclosure, the actuator includes a flexible membrane 114 that divides cavity 104 into a first chamber 116 and a second chamber 118. Actuator 112 further includes an actuation element 120 operable to move membrane 114.

[0036] According to an advantageous example of the present disclosure, the actuator 112 is of the type that uses a buckling membrane 114. To deflect the membrane 114, the actuator 112 includes a piezoelectric driving element 122 that exerts a radial force on the membrane 114, causing it to deflect in a rapid buckling motion. This type of actuation has the advantage that the amount of deflection for a given amount of energy applied by the actuation element 120 is much greater than with actuators in which the actuation element exerts only a bending force perpendicular to the plane of the membrane.

[0037] In this example, the piezoelectric drive element 122 includes a first drive element 122A and a second drive element 122B. As shown in FIG. 1 , the first and second drive elements 122A and 122B are attached to opposite sides of the membrane 114. By actuating the first and second drive elements 122A and 122B, different tensile stresses can be applied to peripheral regions of the membrane 114, causing the membrane to buckle. In the illustrated example, the piezoelectric drive element 122 is movably supported on a flexible bearing 124. The flexible bearing may be formed, for example, from two O-rings made of an elastic material that are held in corresponding notches 126 in the base 102. Of course, any other suitable type of bearing may be used. Because the actuator 112 is flexibly mounted, the piezoelectric drive element 122 can tilt to follow the movement of the membrane 114.

[0038] The first and second drive elements 122A, 122B are positioned on the membrane 114 so as to engage only a peripheral region of the membrane 114. The membrane 114 is absent where the flexible bearing 224 engages the first and second drive elements 122A, 122B.

[0039] According to the present disclosure, the membrane 114 has one or more through-holes 128. These through-holes have the primary advantage of providing pressure compensation between the first chamber 116 and the second chamber 118. A further important advantage of providing at least one through-hole 128 in the membrane 114 is the ability to control fluid flow along a linear path, such as through a pipe. As can be seen in FIG. 1 , the first opening 106 serves as an inlet for the fluid flow 110, which then passes from the first chamber 116 through the through-hole element 128 into the second chamber 118. The second opening 108 serves as an outlet for the fluid flow 110, and by connecting the first opening 106 and the second opening 108 to appropriate piping, the flow through the linear fluid path can be controlled by opening or closing the valve 100.

[0040] The microvalve 100 includes a valve seat 130 disposed around the first opening 106. Advantageously, the valve seat 113 is fabricated from an elastic material and is therefore compressible. In the first state shown in FIG. 1 , the membrane 114 is deflected upward toward the second opening 108, allowing the fluid flow 110 to pass through the first opening 106 into the first chamber 116 and through the through-hole 128 into the second chamber 118. The second opening 108 serves as an outlet. When a pump or other pressure differential between the inlet and outlet drives the fluid flow 110, the fluid flow 110 can easily flow in the direction indicated by the arrows shown in FIG. 1 .

[0041] 2 shows a second state of the microvalve 100 in which the membrane 114 is actuated to move toward the valve seat 130. In this position, the center of the membrane 114 contacts the periphery of the valve seat 130, thereby sealing the first opening 106. As a result, fluid flow 110 is blocked by the microvalve 100.

[0042] The mechanical properties of the membrane 114 and its bearing via the piezoelectric drive element 122 within the substrate 102 can be selected so that the valve is bistable. This means that energy only needs to be applied to the piezoelectric drive element 122 to change the position of the membrane 114 from the first state shown in Figure 1 to the second state shown in Figure 2 and back again; the piezoelectric drive element 122 does not need to be specifically energized to maintain either of these two positions. This allows for particularly low energy operation of the microvalve 100.

[0043] Furthermore, the presence of holes 128 allows for very quick and easy movement of membrane 114 .

[0044] As discussed above, these flexible and / or resilient supports 124 can be compressed within a range while maintaining their flexibility and thus allowing movement of the actuator 112. This allows for continuous support throughout the entire range of actuation. Additionally, this flexibility range can be utilized during the assembly process by shifting the initial position of the actuator 112 within the device, thereby adjusting, for example, the size of the opening gap of the valve 100.

[0045] This ability to move the actuator 112 by compressing the flexible ring 124 without affecting its behavior can also be used to compensate for manufacturing and / or assembly tolerances, whether resulting from surface roughness, tilt, tolerances, thermal contraction and expansion, part aging, or any other form of imperfection. The flexible support of the actuator can compensate for these imperfections, for example, by creating a more uniform support and sealing surface, which can provide the required geometric, mechanical, and fluid properties.

[0046] Additionally, the ability to move the actuator 112 during assembly, and thereby adjust the opening clearance of the valve 100, can be used to calibrate the valve 100 for required performance, such as flow rate, pressure, or response time. For example, calibrating the valve to have a larger initial clearance can increase the final allowable flow rate of the valve, whereas calibrating the valve to have a smaller clearance can increase the pressure tolerance of the valve.

[0047] At least one through-hole 128 is located in an area outside the center of the flexible membrane 114 that is not covered by the piezoelectric actuation element. This configuration advantageously allows for controlled fluid flow between two opposing openings and ensures maximum efficiency, since the opening to be closed can be located at a position of maximum membrane deflection. In addition, both sides of the actuator are advantageously exposed to pressure, which reduces the net pressure the actuator must operate against. Therefore, using the same energy, the valve 100 can operate against higher pressures.

[0048] Additionally, compensation of pressure across the actuator 112 facilitates proportional operation of the valve. Unlike a switching valve, which only provides a final open or closed state, a proportional valve can provide states in between, thus controlling the final outlet flow rate of the valve under the same applied pressure, for example. This enables a wide range of applications, such as applying a uniform pressure to a cell culture, counteracting fluctuating boundary conditions, or delivering a specific flow rate / pressure according to a control signal.

[0049] The pressure compensation along with the flexible support of the elastomeric ring 124 during a wide range of operation and the combination of bending and buckling can improve the proportionality of the valve 100 in various aspects, such as accuracy, control, and operating range.

[0050] 3 and 4 show a further advantageous example of a microvalve 200. The microvalve 200 is a 3 / 2-way valve, i.e., it has three ports and two states. The actuator 212 is constructed and supported in a substrate 202 in the same manner as the actuator 112 described above with reference to FIGS. 1 and 2. The 3 / 2-way valve may be used, for example, in combination with a pressure source (such as a pump) that supplies pressure to its inlet port 1. In a first state, the valve applies pressure to a target outlet (such as a reservoir or cell membrane) connected to port 2, and in a second state, the pressure can be relieved by connecting this outlet (port 2) to a vent (port 3).

[0051] Microvalve 200 differs from microvalve 100 described with reference to FIGS. 1 and 2 in that a first valve seat 230 is disposed around first opening 206 (also referred to as port 1) and a second valve seat 232 is provided around second opening 208 (port 3). Thus, membrane 214 can be actuated between a first position (FIG. 3) and a second position (FIG. 4), sealing one of the ports in both positions. In the first position, membrane 214 contacts second valve seat 232 to seal second opening 208 (port 3). In the second position, membrane 214 contacts first valve seat 213, thereby closing first opening 206 (port 1).

[0052] Additionally, the base 202 is provided with a third opening 207 (Port 2) that extends into the first chamber 216. As a result, as shown in Figure 3, in a first state, fluid flow 210 can enter the first chamber 216 through opening 206 (Port 1) and exit the first chamber 216 through the third opening 207 (Port 2). Because the second opening 208 is closed by the membrane 214 pressing against the second valve seat 232, no fluid flow 210 exits the microvalve 200 through the second chamber 218.

[0053] In contrast, in the second state shown in FIG. 4 , the membrane 214 presses against the first valve seat 230, sealing the first opening 206 (port 1). Therefore, fluid flow 210 can pass through the third opening 207 (port 2), through the perforations 228, and into the second chamber 218. The fluid flow 210 exits the microvalve 200 in this state through the second opening 208 (port 3). Advantageously, in this configuration, a 3 / 2-way valve can be realized using only one actuator 212. Pressure is partially compensated on both sides of the actuator 212. Thus, the actuator 212 can operate against a higher range of pressures, or require less actuation energy to close against a given pressure. Of course, depending on the pressure required and the pressure built up at each port, various different configurations of the three ports can be used to achieve optimal performance.

[0054] By using two or more microvalves and combining them with interconnections between substrates, valve assemblies (or manifolds) with much more complex flow patterns can be realized. A first example of a microvalve manifold 300 is shown in Figures 5 and 6.

[0055] In particular, Figure 5 illustrates a first state of the 5 / 2-way valve assembly. Figure 6 illustrates a second state of the 5 / 2-way valve assembly. The microvalve manifold 300 includes two microvalves 200 as described with reference to Figures 3 and 4. A first microvalve 200A is positioned adjacent to a second microvalve 200B. Note that the two microvalves 200A, 200B are depicted rotated 180° compared to the representations shown in Figures 3 and 4.

[0056] The first opening 206 of the first microvalve 200A forms port 4, and the third opening 207 forms port 2. In the state shown in FIG. 5 , the membrane of the first microvalve 200A is deflected to seal port 4. Port 2 is thus connected to the second chamber 218 via the through-hole 228. To interconnect the two microvalves 200A, 200B, the microvalve manifold 300 includes a fluid path 302 that is in fluid contact with each of the second openings 208 of the two microvalves 200A, 200B. A port 304 (referred to as port 1 in FIGS. 5 and 6 ) is provided in the fluid path 302 to allow fluid flow 310 into or out of the microvalve manifold 300.

[0057] Both membranes 214 of microvalves 200A and 200B include through-holes 228. The membranes 214 are operated to move synchronously in opposite directions relative to each other. In a first state, shown in FIG. 5 , the membrane 214 of the first microvalve 200A, i.e., the first opening 206, is unobstructed, allowing fluid to flow from port 1 through fluid path 302 into the second chamber 218. Fluid flow 310 then passes through through-hole 228 into the first chamber 216 and exits the microvalve manifold 300 through the third opening 207 (port 2). Simultaneously, the membrane 214 of the second microvalve 200B closes its second opening 208 such that ports 3 and 5 are fluidly interconnected.

[0058] With the microvalve manifold 300, a 5 / 2-way valve assembly can be realized by using two actuators, both with perforations, and a substrate-to-substrate connector. Pressure is partially compensated on both sides of the actuator. Thus, the actuator can operate against a higher range of pressures or require less actuation energy to close against a certain pressure. Depending on the pressure and flow rate required at each port, various configurations of the five ports can be realized for optimal performance.

[0059] 5 / 2-way valves are sometimes used to switch between a pump's vacuum and pressure ports in flow switching applications. To do this, in one state, the pump's pressure port must be connected to a target outlet, while the pump's vacuum must be connected to a vent. In the second state, the pump's vacuum port is connected to a target outlet, while its pressure port is connected to a vent. Applications range from intermittent pneumatic compression, deep vein thrombosis prevention, pick-and-place machines, and pipetting robots.

[0060] As noted above, the individual microvalves need not be arranged side-by-side as is shown in Figures 5 and 6, but may be stacked one on top of the other, resulting in a much more compact structure for microvalve manifold 300.

[0061] Additionally, three or more microvalves may be combined to form a microvalve manifold, and it is not necessary for all actuators used to utilize membranes with through-holes.

[0062] An example of a microvalve manifold 400 forming a 3 / 3-way valve (i.e., having three ports and three states) is described below with reference to Figures 7-9. Figures 7, 8, and 9 each show one of three different states. Applications for the 3 / 3-way valve include systems that require two states, a compressed outlet port and a vented outlet port, but are also capable of maintaining the original pressure state of the outlet port.

[0063] As can be seen in Figures 7, 8, and 9, microvalve manifold 400 is essentially a combination of microvalve 200, as described with reference to Figures 3 and 4, and microvalve 500, which has a membrane that may not have through-holes. An example of this is shown in the figures. Of course, although not shown in the figures, the membrane may also have holes for pressure compensation. Apart from the lack of holes in flexible membrane 514, actuator 512 is supported and operates in exactly the same way as actuator 212 described with reference to Figures 3 and 4.

[0064] The two microvalves 200, 500 are interconnected with each other by a fluid path 402. This fluid path 402 is fluidly connected to the third opening 207, 507, so that the third opening 207, 507 does not form a port.

[0065] In the first state ( FIG. 7 ), both membranes 214, 514 are actuated and deflected toward their respective second chambers 218, 518. Thus, the first openings 206, 506 surrounded by the valve seats 230, 530 are unobstructed, allowing fluid flow 410 to flow from the first opening 206 (port 1), through the third opening 207 and fluid path 402, into the third opening 507 of the second microvalve 500, and out through the first opening 506 (port 2). Simultaneously, the second opening 208 (port 3) of the first microvalve 200 is closed by the membrane 214 sealing against the valve seat 232.

[0066] In this state, fluid flow 410 can be directed from port 1 through the microvalve fluid path 402 toward port 2.

[0067] In the second state (shown in FIG. 8), the membrane 514 still holds port 2 open, and the membrane 214 is actuated to buckle towards the first opening 206 (port 1).

[0068] The first microvalve 200 has an opening 228 such that fluid flow 410 entering the first chamber 216 through the third opening 207 can flow into the second chamber 218. The fluid flow 410 can exit the microvalve manifold 400 through the second opening 208 (port 3) if the fluid is driven by a pressure differential or a pump. Thus, the fluid flow 410 is directed to flow from port 2 to port 3.

[0069] 9 shows a third state, in which both membranes 214, 514 are in sealing contact with the first valve seats 230, 530. Thus, fluid cannot enter either ports 1 or 2, and the microvalve manifold 400 is completely sealed.

[0070] In summary, the microvalve manifold 400 can be used to provide a 3 / 3-way valve assembly using two actuators 512, 212 and a substrate-to-substrate connection 402. By providing through-holes 228 in one of the membranes 214, pressure is partially compensated on both sides of the actuator 212. Thus, the actuator 212 can operate against a higher range of pressures or require less actuation energy to close against a given pressure at ports 1 or 3. Depending on the pressure required at each port, various configurations of openings can be used to achieve optimal performance.

[0071] As noted above, the individual microvalves 200, 500 need not be arranged side-by-side as shown in Figures 7-9, but may be stacked one on top of the other, resulting in a much more compact structure for the microvalve manifold 400.

[0072] Additionally, three or more microvalves may be combined to form a microvalve array manifold, and it is not necessary that all actuators used use membranes with through-holes. [Explanation of symbols]

[0073] 100 Microvalves 102 Base 104 Cavity 106 First Opening 108 Second Opening 110 Fluid flow 112 Actuator 114 Membrane 116 Room 1 118 Second Room 120 Actuating Elements 122 Piezoelectric driving element 122A, 122B First and second driving elements 124 Flexible Bearings 126 Notch 128 Through Hole 130 Valve seat 200 Microvalves 202 Base 204 Cavity 206 First Opening 208 Second Opening 210 Fluid flow 212 Actuator 214 Membrane 216 Room 1 218 Second Room 220 Actuating Elements 222 Piezoelectric Drive Elements 222A, 222B First and second drive elements 224 Flexible Bearings 226 Notch 228 Through Hole 230 First valve seat 232 Second valve seat 300 Micro Valve Manifold 302 Fluid path 310 Fluid Flow 400 Micro Valve Manifold 402 Fluid path 410 Fluid Flow 500 Microvalves 502 Base 504 Cavity 506 First Opening 508 Second Opening 512 Actuator 514 Membrane 516 Room 1 518 Second Room 520 Actuating Elements 522 Piezoelectric Drive Element 522A, 522B First and second drive elements 524 Flexible Bearing 526 Notch 530 First valve seat

Claims

1. a substrate having a cavity and at least one first opening and at least one second opening, each opening extending into the cavity; a flexible membrane dividing the cavity into a first chamber and a second chamber; an actuation element supported by the base, in contact with the flexible membrane, and operable to deflect the membrane to move between at least two positions; Equipped with The flexible membrane includes at least one through hole extending between the first chamber and the second chamber.

2. The microvalve of claim 1 , wherein the at least one first opening is positioned to extend into the first chamber and the second opening is positioned to extend into the second chamber.

3. 3. The microvalve of claim 1, wherein at least one of the at least one first opening and the at least one second opening is provided with a valve seat, and the flexible membrane is operable to contact the valve seat to close the respective at least one first opening and / or at least one second opening in one of the positions.

4. 4. A microvalve according to claim 1, wherein the at least one through-hole is arranged to remain unobstructed in all of the positions.

5. 5. A microvalve according to any one of claims 1 to 4, wherein the actuation element comprises at least one ring-shaped piezoelectric drive element, and the flexible membrane is operable to buckle upon actuation of the piezoelectric drive element.

6. The microvalve of claim 5 , wherein the piezoelectric actuation element is movably supported about a peripheral region.

7. The microvalve according to claim 5 or 6, wherein the at least one through-hole is located in an area outside the center of the flexible membrane that is not covered by the piezoelectric driving element.

8. 8. The microvalve of claim 1, wherein the actuation element comprises a first piezoelectric drive element and a second piezoelectric drive element, and the flexible membrane is supported between the first piezoelectric drive element and the second piezoelectric drive element.

9. 9. A microvalve as described in any one of claims 1 to 8, wherein two first openings extend into the first chamber and one second opening extends into the second chamber, and wherein a valve seat is provided at the second opening and at the opposite side of the first opening, and each valve seat is contactable by the flexible membrane.

10. The microvalve of claim 9 , wherein the at least one through-hole is located in a region of the flexible membrane that is not in contact with the valve seat.

11. A microvalve array comprising at least one microvalve according to any one of claims 1 to 10.

12. 12. The microvalve array of claim 11, comprising at least a first microvalve and a second microvalve, the first microvalve and the second microvalve being interconnected by a fluid path connected to their respective first openings, the first openings being closable by movement of the respective flexible membranes.

13. 13. The microvalve array of claim 11 or 12, wherein the first microvalve and the second microvalve each include two second openings, and the flexible membrane of each of the first and second microvalves is movable to close either the respective first opening or the second opening located opposite the first opening.

14. 14. The microvalve array of claim 11, comprising at least two microvalves interconnected by a fluid path connected to a respective second opening, the second opening not being closable by movement of the respective flexible membrane.

15. 15. The microvalve array of claim 11, further comprising microvalves having flexible membranes without through-holes.

Images