Fluid control of micro-electromechanical systems

Abstract

The fluid control device (1) comprises a stack of wafers (20) on which flow components (10A-D) are provided as microelectromechanical systems - MEMS. The flow components (10A-D) are selected from fluid control components (11A-C) and / or fluid monitoring components (12). The fluid control device (1) has, in a major plane of the stack of wafers, a first flow component (10A) surrounded by a second flow component (10B).

Description

Technical Field

[0001] This technology generally relates to fluid control systems, and in particular to fluid control systems implemented as microelectromechanical systems.

Background Art

[0002] Microelectromechanical systems (MEMS) are today used to implement many different types of microactuators or microsensors in a cost-effective and space-saving manner. One application where MEMS are commonly used is in microfluidic control devices. Consideration of different microfluidic applications can be found, for example, in the article “A Review of Passive Constant Flow Regulators for Microfluidic Applications” by E. Chappel in Applied Sciences 2020, 10, 8858 on December 10, 2020.

[0003] A common endeavor in such MEMS applications is to make the fluid control device as small as possible and to facilitate manufacturing. MEMS are typically based on machined wafers that are joined together as a unit. In that regard, it is common for the number of wafers required to achieve the fluid control operation to be a critical parameter. The more wafers required, the more difficult the joining becomes. Thus, the general trend is to minimize the number of wafers required.

[0004] Typical fluid control devices include several flow components. Such flow components can be, for example, fluid control components such as filters, valves, regulators, etc., and / or fluid monitoring components such as pressure sensors, flow sensors, etc. Such flow components are fluid-connected in series and / or in parallel in different configurations to achieve the overall flow functionality required.

[0005] An example of a fluid control device is a pressure regulator designed to provide a continuous flow of low-pressure gas from a high-pressure storage tank. Many solutions have been proposed, most of which involve several flow components, such as several depressurization stages.

[0006] However, as the need for more flow components increases, the problem arises of how to geometrically position the flow components relative to each other in order to achieve an overall configuration that is easy to manufacture. Stacking flow components in the thickness direction of the MEMS is perhaps the easiest solution conceptually, but as shown above, the bonding complexity increases significantly with increasing numbers of wafers required.

[0007] An alternative approach involves arranging the flow components side-by-side within the main plane of the wafer. However, even here, increasing the number of flow components results in the entire fluid control device exhibiting a relatively large spread within the wafer plane. This generally increases production costs and can also lead to problems such as mechanical strength issues.

[0008] U.S. Patent No. 5,839,467, which has been published, discloses a microfabricated fluid handling device. Different film-containing components are positioned side by side.

[0009] The published U.S. patent application No. 2017 / 01762677 A1 discloses a pressure sensor chip in which a high differential pressure diaphragm is positioned side-by-side on the same surface as several low differential pressure diaphragms.

[0010] A further alternative approach is to attempt to integrate two or more specific functionalities within each flow component in order to reduce the number of flow components. However, such methods often require considerable construction effort and can typically result in highly application-specific solutions. Therefore, such methods are often time-consuming and costly. [Overview of the project]

[0011] The overall objective of the technologies presented here is to discover novel concepts for constructing fluid control devices that are easy and inexpensive to develop and manufacture, and in particular for fluid control devices that require many steps or components.

[0012] The above objectives are achieved by methods and devices according to the independent claims. Preferred embodiments are provided in the dependent claims.

[0013] Generally speaking, in the first embodiment, the fluid control device includes a stack of wafers in which the flow components are provided as micro-electromechanical systems—MEMS. The flow components are selected from fluid control components and / or fluid monitoring components. The fluid control device has a first flow component in the main plane of the stack of wafers, surrounded by a second flow component. First and second The flow components include their respective deformable membranes.

[0014] One advantage of the proposed technology is that the spread of the fluid control device within the main plane of the wafer stack can be kept small. Other advantages will be understood when reading the detailed explanation.

[0015] The present invention, along with further objectives and advantages, can be best understood by referring to the following description in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic cross-sectional view of an embodiment of a conventional MEMS pressure regulator. [Figure 2] This is a schematic cross-sectional view of an embodiment of a conventional MEMS flow control device having two pressure regulators. [Figure 3] This is a schematic cross-sectional view of another embodiment of a conventional MEMS flow control device having two pressure regulators. [Figure 4]A schematic diagram in which flow components are arranged side by side and are not literally included in the claims of this patent. [Figure 5] A schematic diagram in which flow components are placed surrounding each other. [Figure 6] A schematic cross-sectional view of a further embodiment of a MEMS flow control device having two pressure regulators. [Figure 7] A schematic cross-sectional view of a further embodiment of a MEMS flow control device having two pressure regulators. [Figure 8] A schematic cross-sectional view of an embodiment of a MEMS flow control device having two pressure regulators and a filter. [Figure 9] A schematic cross-sectional view of another embodiment of a MEMS flow control device having two pressure regulators and a filter. [Figure 10A] A schematic cross-sectional view of an embodiment of a MEMS flow control device having both a fluid control component and a fluid monitoring component. [Figure 10B] A schematic elevation view of the flow control device of FIG. 10A. [Figure 11A] A figure schematically illustrating different flow paths through a series of flow components. [Figure 11B] A figure schematically illustrating different flow paths through a series of flow components. [Figure 11C] A figure schematically illustrating different flow paths through a series of flow components. [Figure 12A] A schematic cross-sectional view of an embodiment of a MEMS flow control device having five pressure regulators and a check valve. [Figure 12B] A schematic elevation view of the flow control device of FIG. 12A. [Figure 13] A cross-sectional view of an embodiment of a piston structure. [Figure 14A] A figure illustrating an embodiment of a sheet structure. [Figure 14B] A figure illustrating an embodiment of a sheet structure. [Figure 14C] A figure illustrating an embodiment of a sheet structure. [Figure 15A] A diagram illustrating an embodiment of the arrangement of distance elements. [Figure 15B] A diagram illustrating an embodiment of the arrangement of distance elements. [Figure 15C] A diagram illustrating an embodiment of the arrangement of distance elements.

Embodiments for Carrying out the Invention

[0017] Throughout the drawings, the same reference numerals are used for like or corresponding elements.

[0018] For a better understanding of the proposed technology, it may be useful to begin with a brief discussion of the advantages and problems associated with MEMS arrangements. As briefly touched upon in the background art, MEMS are very advantageously used to provide single - flow components. However, problems arise when more complex system requirements are made. Using a MEMS stack of wafers based on two or three wafers joined to each other is relatively easy and can be considered a standard procedure. Already a 4 - wafer stack creates additional complexity and can be considered a non - standard procedure. A 5 - wafer stack is more difficult to handle but may still be achievable with great effort. A wafer stack with six or more wafers should be considered advanced special - effect manufacturing, at least with today's available technology. For these reasons, most of the work related to MEMS is spent finding designs suitable for low - wafer - number MEMS stacks.

[0019] A pressure regulator system may be used as a model system in this disclosure. There are many applications that require regulating the gas pressure from a high storage tank to a lower operating pressure. In many applications, it is sufficient for the regulator to deliver a constant output pressure, but other applications require the ability to change the outlet pressure. Regulators can be either passive or active. Active pressure regulators require energy to monitor the pressure read from a sensor and adjust the valve position to achieve the desired pressure. Passive regulators typically rely on the tension of a membrane or spring to regulate the pressure. This is preferred in many applications because it does not require any energy supplied from the outside.

[0020] Figure 1 shows Literally, prior art not included in the claims of this patent. An embodiment of the fluid control device 1 is schematically illustrated. This embodiment presents a flow component 10, in this case a fluid control component 11, and in particular a pressure regulator 30. The fluid control device 1 is provided with MEMS technology and is therefore fabricated by a structure in a stack of wafers 20. In this design, a balance is taken between a high-pressure film 32 having a small area and a regulating pressure film 38 having a large area.

[0021] In this embodiment, the regulator inlet 31 allows high-pressure gas to come into contact with the high-pressure membrane sealing surface. A narrow passage 33 exists between the high-pressure membrane sealing surface 35 and the sheet structure 34. The gas flows into the connecting channel 40 via the high-pressure side volume 44, which is in contact with one side of the high-pressure membrane 32, and finally through the regulator outlet 39. The narrow passage 33 causes flow restriction, and therefore the gas in the high-pressure side volume 44 and the connecting channel 40 has a reduced regulated pressure. This gas with regulated pressure is in fluid communication with the regulated pressure cavity 41, which is in contact with one side of the regulated pressure membrane 38. The regulated pressure membrane 38 and the high-pressure membrane 32 are connected by a piston structure 36 surrounded by a reference pressure chamber 37. If the pressure in the outlet pressure cavity 41 is higher than that in the reference pressure chamber 37, the regulated pressure membrane 38 tends to bend upward in the figure, pushing the piston structure 36 upward. However, the pressure difference between the high-pressure volume section 44 and the reference pressure chamber 37 tends to push the piston structure 36 downward, but because the area of ​​the high-pressure membrane is much smaller than the area of ​​the regulating pressure membrane 38, the resultant force on the piston structure 36 is directed upward in the figure. The high pressure acting on the central portion of the high-pressure membrane sealing surface 35 also helps to push the piston structure 36 downward. When the upward force is dominant, the high-pressure membrane sealing surface 35 is prompted to close the narrow passage 33 between the high-pressure membrane sealing surface 35 and the sheet structure 34.

[0022] Therefore, an equilibrium action exists between the gases flowing through the narrow channel 33, thereby constructing a regulated pressure, and the pressure in the regulated pressure cavity 41 moves the piston structure 36 upward in the figure, attempting to close the narrow channel 33. When the flow outward from the regulator outlet 39 is stopped or restricted, the regulated pressure increases until the narrow channel 33 is closed. The increased regulated pressure also acts on the outer portion of the high-pressure membrane 32, but since the area of ​​the regulated pressure membrane 38 in contact with the increased regulated pressure is typically larger, the resultant force acts to close the narrow channel 33. When the flow outward from the regulator outlet 39 is permitted again, the regulated pressure decreases, and the narrow channel 33 is opened.

[0023] To restrict the movement of the piston assembly 36, the regulating pressure film support surface 43 is positioned so as to be stopped by the low-pressure support structure 42. The rotational symmetry, as indicated by R, applies to all members except the connecting channel 40, which may rather exist as one or more distinct channels distributed around the central structure.

[0024] The critical dimensions of the pressure regulator 30 are the radius of the high-pressure membrane 32, the radius of the regulating pressure membrane 38, and the valve gap of the narrow flow path 33.

[0025] When a moderate pressure difference is required for a pressure regulator, especially at medium pressures, the above concept can be designed to operate almost independently of the original pressure, with a constant output flow, because the high-pressure contribution to piston displacement is typically small. However, when high pressure reduction and / or high input pressure are required, the level of the original high pressure becomes more important in determining the final output flow. Therefore, in many applications, the use of two-stage pressure reduction, or even multi-stage pressure reduction, is required, in which case the pressure regulators are provided in series and reduce the pressure in two or more steps.

[0026] Literally, prior art not included in the claims of this patent. One embodiment of the design of a two-stage MEMS pressure regulator assembly 13 is illustrated in Figure 2. Here, the regulator outlet 39 of the first pressure regulator 30A is connected to the regulator inlet 31 of the second pressure regulator 30B. However, it should be immediately recognized that such a design requires the use of many wafers to be connected to each other in a stack of wafers 20. Therefore, the manufacture of such a device is extremely difficult, if possible.

[0027] Literally, prior art not included in the claims of this patent.Another embodiment of the design of the two-stage MEMS pressure regulator assembly 13 is illustrated in Figure 3. Here, the pressure regulators 30A and 30B are still provided in a series configuration from a fluid perspective. Each regulator 30A, 30B has its own rotational symmetry around their respective line R, except for a few connecting passages. However, physically, the regulators are placed side by side in a stack of wafers 20. This is currently considered to reduce the number of wafers required in the stack, and due to the connecting passage 45 between the pressure regulators 30A and 30B, only one additional wafer is required compared to a single pressure regulator. However, the lateral space occupied is twice that of a single pressure regulator. Thus, although this embodiment is more attractive, from the viewpoint of its further flow components, both fluid control components, e.g., additional depressurization steps, valves, or filters, and fluid monitoring components, e.g., flow pressure sensors, may be required in different applications, and the lateral spread of the entire system can become unfavorably large.

[0028] Most flow components, at least those based on membrane behavior, have circular symmetry. Figure 4 shows that Literally, prior art that is not included in the claims of this patent, A fluid control device 1 having a main inlet 2 to a first flow component 10A is schematically illustrated. This is illustrated showing the main plane of the wafer 20 stack, i.e., perpendicular to the extended plane of the wafer used to create the MEMS. Subsequent flow components 10B-D are then connected in series until they reach a main outlet 3 (on the back side of the wafer 20 stack). The geometric dimensions of such a design are much larger than those of a unidirectional component design.

[0029] However, this technology concludes that flow components, and membrane-based flow components, can be designed with a circular shape, but with a “passive” central portion. That is, the active structure can be designed within a space defined by an inner and outer radius. In other words, the active structure does not need to reach the center of a ring-shaped symmetry. The space around the axis of symmetry is not necessarily used.

[0030] Such insights lead to a novel concept for designing flow control devices having two or more flow components. Figure 5 is a schematic diagram of an embodiment of a fluid control device 1, functionally similar to that illustrated in Figure 4. This is also illustrated by showing the main plane of a stack of wafers 20. Here, a first flow component 10A is provided in the center. A second flow component 10B is provided around this first flow component 10A. The working area of ​​flow component 10B is equal to the working area of ​​flow component 10A, but the width of the working area is smaller because it is provided with a larger radius. Flow components 10A and 10B thus efficiently utilize the available area and increase the density of the actively utilized area portion. Two more flow components 10C and 10D are then provided concentrically outside the inner ones. If the flow components are accompanied by a deformable film, all flow components except the innermost possible one utilize a ring-shaped film. The ring shape is a circular ring in the figure. However, the ring shape can be any closed geometric shape, such as an ellipse or a polygon.

[0031] Even when the working area cannot be significantly reduced, the space savings achieved by placing precisely matched flow components 10A-D concentrically outside each other are evident. The outer flow components surround the inner flow components. In other words, the inner flow components are entirely contained within a region completely enclosed by the outer flow components. In many applications, the connection paths between flow components can be provided within the existing wafer stack thickness, and in such applications, extra wafers are not required to ensure the connection paths.

[0032] Therefore, in other words, in one embodiment, a fluid control device comprising a stack of wafers, the flow components being provided as MEMS, the first flow component being surrounded by a second flow component in the main plane of the stack of wafers, each of the flow components being either a fluid control component or a fluid monitoring component.

[0033] In a further embodiment, a third flow component surrounds a second flow component in the main plane of the wafer stack.

[0034] In yet another embodiment, a fourth flow component surrounds a third flow component in the main plane of the wafer stack.

[0035] In a generalized embodiment, this can be represented as a fluid control device having n flow components for any number n flow components. The k-th flow component surrounds the (k-1)-th flow component in the main plane of the wafer stack, where k is an integer less than or equal to n but greater than 1. The number n may be greater than 4.

[0036] These ideas can be advantageously applied to applications of pressure regulators.

[0037] Figure 6 schematically illustrates a cross-section of an embodiment of a fluid control device 1, in this embodiment, a pressure regulator system. The fluid control device 1 includes two flow components 10, both of which are fluid control components 11, and in particular a first pressure regulator 30A and a second pressure regulator 30B. Note that since the second pressure regulator 30B surrounds the first pressure regulator 30A in the main plane of the stack of wafers 20, portions of the second pressure regulator 30B appear on both sides of the first regulator 30A in the figure. The first and second regulators 30A and 30B have a common axis of symmetry R in most portions, except for the connecting channel 40 between the high-pressure and low-pressure sides and the connecting passage 45 between the regulators 30A and 30B. The fluid control device 1 has a smaller total radius than a design using side-by-side pressure regulators and can be implemented with the same number of wafers as a single pressure regulator.

[0038] Therefore, the second pressure regulator 30B has a substantially cylindrical shape, leaving room inside for use for other purposes. In this case, the first pressure regulator 30A occupies this volume and is therefore surrounded by the second pressure regulator 30B. Similar to those described above and in common with other flow components, the second pressure regulator 30B includes a deformable membrane. The second pressure regulator 30B has a high-pressure membrane 32 that, when deformed, is positioned to enable a sealing effect on the sheet structure 34.

[0039] The second pressure regulator 30B further has a pressure regulator flow path including a connecting channel 40 that runs from a pressure regulating membrane 38 and a high-pressure inlet 61 through the space between the high-pressure membrane 32 and the sheet structure 34, i.e., through a narrow flow path 33, to a low-pressure outlet. The first side of the pressure regulating membrane 38, facing downward in the figure, is in fluid contact with the low-pressure outlet 62 of the pressure regulator flow path.

[0040] The fluid contact between the first side described above on the regulating pressure membrane 38 and the low-pressure outlet 61 of the pressure regulator flow path includes an outlet pressure cavity 41. The outlet pressure cavity 41 is in contact with the regulating pressure membrane 38.

[0041] The second pressure regulator 30B, similar to the first pressure regulator 30A, further includes a piston assembly 36 connecting the high-pressure membrane 32 and the regulating pressure membrane 38. Thus, a reference pressure chamber 37 is formed between the high-pressure membrane 32 and the regulating pressure membrane 38, surrounding the piston assembly 36. In other words, at least two flow components 10 include their respective deformable membranes 32 and 38.

[0042] In Figure 6, the first pressure regulator 30A is of a “conventional” type with circular symmetry, having an operating portion within the axis of symmetry, while the second pressure regulator 30B instead has a cylindrical shape with a non-operating central volume. The volume around the axis of symmetry R is often useful for many other functions, and it may be advantageous to leave at least a portion of this volume unused. In other words, components that can be implemented in a cylindrical shape may be placed further outward, and the central volume is reserved for components or connections that may need to be placed there. Figure 7 schematically illustrates a cross-sectional view of such an embodiment, where both the first pressure regulator 30A and the second pressure regulator 30B are of the cylindrical type with their respective internal volumes left unused.

[0043] In the embodiments described above, at least one flow component is a fluid control component. In further embodiments, the fluid control component is selected to be a pressure regulator, a valve, or a filter.

[0044] In one embodiment schematically illustrated in Figure 8, a first fluid control component 11A, which functions as a filter 50, is provided within the central volume portion of the stack of wafers 20 around the line of symmetry R. A second fluid control component 11B, in the form of a first pressure regulator 30A, is provided surrounding the filter 50. A third fluid control component 11C, in the form of a second pressure regulator 30B, is provided surrounding the first pressure regulator 30A.

[0045] The embodiment shown in Figure 8 therefore includes two pressure regulators 30A and 30B. Pressure regulators 30A and 30B have a high-pressure side and a low-pressure side. The high-pressure side of the two pressure regulators 30A and 30B is provided near the first side of the fluid control device 1.

[0046] Figure 9 illustrates yet another embodiment of the fluid control device 1. Here, the high-pressure sides of two pressure regulators 30A and 30B are provided close to opposite sides of the stack of wafers 20. In other words, the high-pressure side of one of the two pressure regulators and the low-pressure side of the other pressure regulator are provided close to the first side of the fluid control device 1. The connecting channel 40 between the high-pressure and low-pressure sides and the connecting passage 45 between the regulators 30A and 30B can then be arranged differently, thereby providing greater design flexibility.

[0047] Figure 10A illustrates another embodiment of the fluid control device 1. Note that only about half of the device is illustrated here, and the line of symmetry R is located on the far left of the figure. In this embodiment, the fluid control device 1 includes four flow components 10A to 10D. Flow component 10A is the first fluid control component 11A in the form of a first pressure regulator 30A. Flow component 10B is the second fluid control component 11B in the form of a second pressure regulator 30B. Flow component 10C is the fluid monitoring component 12 in the form of a pressure sensor 52. Flow component 10D is the third fluid control component 11C in the form of a check valve 51.

[0048] Figure 10B illustrates the spread of the flow components 10A to D in Figure 10A within the main plane of the wafer stack 10.

[0049] In one embodiment, at least one flow component is a fluid monitoring component. In a further embodiment, the fluid monitoring component is selected to be a pressure sensor or a flow sensor.

[0050] In the diagram, the main inlet and main outlet are illustrated to be located on opposite sides of the wafer stack. This is a typical arrangement for MEMS-based fluid control devices because the wafer stack itself separates the gas volume before and after the fluid control device. However, in certain applications, inlets and outlets on the same side of the wafer stack may be beneficial, and this technique is also well adaptable to implementing such designs.

[0051] Those skilled in the art will recognize that variations are virtually limitless, and that various types of different flow components can be positioned concentrically with respect to one another. In many applications, different flow components are fluidly connected in series, as in the embodiments described above. However, there is also the possibility of designing fluid control devices with parallel branching.

[0052] In the case of fluid-connected flow components in series, it is often convenient to place them as geometrically adjacent flow components. This was the case, for example, in the embodiments presented above. However, in some applications, as in some embodiments further below, two or more fluid-connected flow components in series may be geometrically non-adjacent flow components. This may be, for example, when some flow components are provided at a more advantageously smaller radius or a more advantageously larger radius than other flow components within the same device.

[0053] Figure 11A is a schematic diagram of an embodiment of a stack of wafers 20 of the fluid control device 1. Several flow components 10A to 10G are provided surrounding each other around an axis of symmetry R. Arrows illustrate fluid connections between different flow components. Here, it can be seen that the flow begins to enter the central flow component 10A, then continues to pass through the cylindrical flow components 10B to 10G in succession, and finally exits from flow component 10G.

[0054] In the embodiment shown in Figure 11A, the high-pressure inlet to the fluid control device 1, i.e., the main inlet 2, is centrally located relative to the first flow component 10A.

[0055] The high-pressure inlet to the fluid control device 1 is here fluid-connected to the inlet of the first flow component 10A.

[0056] Figure 11B shows a similar diagram of another embodiment. Here, the flow starts within flow component 10B, continues to flow component 10G, and then returns to the central flow component 10A, from which it finally exits.

[0057] In this embodiment, the low-pressure outlet from the fluid control device, i.e., the main outlet 3, is centrally located relative to the first flow component 10A.

[0058] The low-pressure outlet from the fluid control device 1 is here fluid-connected to the outlet of the first flow component 10A.

[0059] In an alternative embodiment, the actual high-pressure inlet may also be provided within the volume of the first flow component 10A, but is connected to the flow component 10B as the first working component.

[0060] Figure 11C illustrates a more unconventional embodiment, where fluid connections are made only between neighboring flow components 10G and 10F. The majority of the fluid-connected flow components in series are not geometrically adjacent.

[0061] Fluid connections between flow components that are geometrically non-neighboring in order can be provided by adding one or more wafers to a wafer stack. However, other solutions may also be possible in specific applications.

[0062] Figure 12A illustrates an embodiment of a fluid control device 1 having five pressure regulators 30A-30E and a check valve 51. The figure is divided into two parts, the left part illustrated at the top and the right part at the bottom. In this embodiment, the geometric order of the flow components 10A-F starts from the center and proceeds outward. However, a main inlet 2, or rather a number of main inlets 2, is connected to a first pressure regulator 30A, i.e., flow component 10B. The fluid connections, in this case with respect to the number of the flow components, are in the order 10B, 10C, 10D, 10E, 10F, and 10A, which correspond to the pressure regulators 30A, 30B, 30C, 30D, 30E, and finally the check valve 51.

[0063] It has been found that a pressure regulation of approximately 1:3 can be easily achieved at each stage of the five pressure regulators, and that the pressure regulation can be even greater in the downward absolute pressure. This means that a total pressure regulation of more than 250 times can be achieved by such an arrangement.

[0064] A connecting passage 45B exists between the pressure regulator 30E and the check valve 51. In this embodiment, this connecting passage 45B is designed to pass through the reference pressure chamber 37 of the pressure regulators 30A to D. The operation of the pressure regulators 30A to D is not affected at all, as the pressure in the connecting passage 45B is intended to be approximately atmospheric pressure in this embodiment and does not change much during operation. However, this design eliminates the use of additional wafers.

[0065] Figure 12B is a schematic diagram of the lateral distribution of the connecting passage 45, connecting passage 45B, and connecting channel 40 in Figure 12A. In this embodiment, there are five examples of each connecting passage and each connecting channel for each flow component.

[0066] In other words, in one embodiment, the fluid connection between the two flow components passes through a reference pressure chamber.

[0067] The cylindrical shape of the flow components can also influence preferred design details. In the case of a pressure regulator, if the piston component is provided halfway between the radially outer and radially inner walls of the reference pressure chamber, the radially outer membrane area of ​​the (cylindrical) piston is slightly larger than the radially inner membrane area of ​​the piston. The resultant force applied to the radially outer membrane area is therefore higher than the resultant force applied to the radially inner membrane area. Such an uneven distribution of forces may be useful in different applications but undesirable in others.

[0068] However, this can be mitigated by positioning the piston components closer to the radially outer boundary of the high-pressure or regulating pressure membrane than to the radially inner boundary of the high-pressure or regulating pressure membrane, respectively. One preferred configuration is that the area of ​​the regulating pressure membrane located at a radius smaller than the radius of the piston component is equal to the area of ​​the regulating pressure membrane located at a radius larger than the radius of the piston component. Another preferred configuration is that the area of ​​the high-pressure membrane located at a radius smaller than the radius of the piston component is equal to the area of ​​the high-pressure membrane located at a radius larger than the radius of the piston component.

[0069] Figure 13 illustrates a portion of a cross-sectional view of an embodiment of the piston assembly 36, high-pressure membrane 32, and regulating-pressure membrane 38. The radius increases towards the right in the figure. The midpoint of the membrane is indicated by an arrow. Note that in this embodiment, the piston assembly 36 does not need to be mounted to the membrane at its center. The piston assembly 36 on the high-pressure side should not have the same width as the piston assembly 36 on the low-pressure side. This is another design parameter that can be used to fine-tune the stiffness of the membrane. Furthermore, the different parts of the piston assembly should not meet at their respective centers. In this particular embodiment, the high-pressure membrane 32 and the regulating-pressure membrane 38 have the same thickness. However, in an alternative embodiment, they may have different thicknesses. This, too, is a design parameter that will be used to achieve the correct membrane stiffness.

[0070] In certain embodiments, the piston structure is divided into a high-pressure piston portion and a low-pressure piston portion, which are separated by only a small distance in the relaxed state. This means that during operation, a slight bending of the regulating pressure membrane must occur before the two parts actually make mechanical contact. In terms of operation, this means that the control of the high-pressure membrane is somewhat delayed.

[0071] Another detail of pressure regulators that may be used to adapt to pressure drops is the design and dimensions of the sheet structure and the high-pressure membrane sealing surface.

[0072] When high pressures are involved, the forces on the piston structure, high-pressure membrane, and sheet structure can be considerable. To avoid deformation, the area of ​​the sheet structure supporting the load may be increased.

[0073] One further concern regarding the design of the sheet structure is that debris particles can sometimes follow the gas flow and become lodged between the sheet structure and the high-pressure membrane sealing surface, thereby preventing complete occlusion of the narrow flow path within the pressure regulator. Using wider sheet structures increases the risk of particle trapping between the sheet structure and the high-pressure membrane sealing surface.

[0074] In one embodiment designed to mitigate such risks, the sheet structure includes multiple sheet surface loops separated by recesses. Thus, each sheet loop forms a closed structure, and the high-pressure film can form a seal with respect to it. Even if particles become lodged between the high-pressure film sealing surface and one of the sheet surface loops, the high-pressure film sealing surface can still seal against the other sheet surface loops. Furthermore, particles can also be pressed into the space between the sheet surface loops. Multiple sheet surface loops also increase the total contact area, thereby further reducing the contact pressure.

[0075] Figure 14A illustrates a portion of a wafer intended to provide a sheet structure for a pressure regulator 30. The sheet structure 34 includes several sheet surface loops 64 separated by recesses 65. The sheet surface loops 64 constitute the entire circumference, so that each can seal the inner volume from the outer volume relative to the sheet surface loop 64. Connecting passages 45 are provided at several angles and supply gas down to the innermost sheet surface loop 64. Connecting channels 40 are similarly provided outside the outermost sheet surface loops 64. The number of sheet surface loops 64 can be adapted to the properties and dimensions of the high-pressure film intended to provide a seal. The connecting channels 40 are not necessarily provided at the same angles as the connecting passages 45. Furthermore, in alternative embodiments, the flow directions may be opposite, i.e., the connecting passages 45 are provided outward and the connecting channels 40 are provided inward.

[0076] Figure 14B illustrates a portion of a cross-sectional view of an embodiment of fluid control device 1 based on a structure illustrated in Figure 14A. The cross-section is taken in the direction indicated by the arrow in Figure 14A. The high-pressure membrane sealing surface 35 is provided facing the sheet structure 34 and accompanied by a narrow channel 33 separating them. Figure 14C illustrates a situation in which a pressure difference across the high-pressure membrane 32 causes deformation, thereby causing contact between the high-pressure membrane sealing surface 35 and the sheet structure 34, thereby providing a sealing effect. Note that the conceptual particles 66 are trapped in the recess 65 and do not affect the sealing particles.

[0077] As further described above, the regulating pressure membrane preferably has a solid structure for interaction. In a high pressure difference between the pressure in the high pressure membrane and the pressure in the regulating pressure membrane, the regulating pressure membrane may deform to such an extent that it reaches a solid structure at the bottom of the regulating pressure cavity. The membrane may then seal to this surface, and the outflow pressure cavity may not be able to provide the correct pressure reference when the conditions change again. The regulating pressure membrane may therefore stick to the regulating pressure cavity. To solve this problem, the regulating pressure cavity preferably has distance elements provided from the bottom of the cavity. These distance elements are configured to prevent the regulating pressure membrane from reaching the bottom. At the same time, the distance elements allow gas to flow continuously through the regulating pressure cavity and provide the correct pressure reference.

[0078] This is also beneficial in providing a resting position for the regulating pressure membrane 67 without involving excessive deformation that could increase the risk of cracking within the membrane.

[0079] Figure 15A schematically illustrates a portion of a wafer intended to provide a low-pressure support structure 42 for a pressure regulator 30. Several distance elements 67 are provided from the bottom 68 of the regulating pressure cavity 41. Connecting channels 40 serve to provide the regulated pressure gas. To distribute the gas even when the regulating pressure film is in contact with the distance elements 67, the distance elements are broken in some places and do not surround the entire 360 ​​degrees, as opposed to a sheet structure.

[0080] The distance elements 67 can be designed differently, for example, as columns of different shapes. The distance elements 67 should be defined so that they provide support for the regulating pressure film while simultaneously allowing gas to flow between them. Supports that present a low-density surface, i.e., a larger space between the support structures, also contribute to ensuring that a large portion of the regulating pressure film is available for regulating pressure.

[0081] Figure 15B illustrates a portion of a cross-sectional view of an embodiment of fluid control device 1 based on a structure illustrated in Figure 15A. The cross-section is taken in the direction indicated by the arrow in Figure 15A. Here, it can be seen that there is space for gas between the individual distance elements 67. Figure 15C illustrates a situation in which the regulating pressure membrane 38 is deformed and supporting the distance elements 67. The regulating pressure cavity 41, which is in contact with the regulating pressure membrane 38, is still in fluid contact with the connecting channel 40.

[0082] The embodiments described above should be understood as some illustrative examples of the present invention. Those skilled in the art will understand that various modifications, combinations, and alterations can be made to the embodiments without departing from the scope of the invention. In particular, different partial solutions within different embodiments can be combined in other configurations where technically possible. However, the scope of the invention is defined by the appended claims.

Claims

1. A fluid control device (1) comprising a stack of wafers (20) provided as a microelectromechanical system -MEMS, wherein the flow components (10, 10A-F) are selected from at least one of fluid control components (11, 11F) and fluid monitoring components (12), and the first flow component (10A) of the flow components (10, 10A-F) is surrounded by the second flow component (10B) of the flow components (10, 10A-F) in the main plane of the stack of wafers (20), At least the first and second flow components (10A, 10B) each include a deformable film (32, 38), At least one of the flow components (10, 10A to F) is a fluid control component (11, 11A to F), The fluid control device (1) is characterized by including at least one pressure regulator (30, 30A to E), wherein the pressure regulator (30, 30A to E) has a high-pressure membrane (32) that, when deformed, enables a sealing action over the sheet structure (34).

2. The fluid control device according to claim 1, characterized in that the third flow component (10C) surrounds the second flow component (10B) in the main plane of the stack of wafers (20).

3. The fluid control device according to claim 2, characterized in that the fourth flow component (10D) surrounds the third flow component (10C) in the main plane of the stack of wafers (20).

4. The fluid control device according to claim 3, characterized by n flow components (10, 10A to F), where n is an integer greater than 4, the k-th flow component (10E to F) surrounds the (k-1)-th flow component (10D to E) in the main plane of the stack of wafers (20), where k is an integer less than or equal to n but greater than 1.

5. The fluid control device according to claim 1, characterized in that at least two of the flow components (10, 10A to F) are fluidly connected in series.

6. The fluid control device according to claim 5, characterized in that two of the fluid components connected in series are geometrically adjacent fluid components.

7. The fluid control device according to claim 5, characterized in that two of the fluid components connected in series are geometrically non-adjacent fluid components.

8. At least one of the fluid control components (11, 11A to F) is - Pressure regulators (30, 30A to E), - Valve (51), and - The fluid control device according to claim 1, characterized in that it is selected from the group of filters (50).

9. The fluid control device according to claim 1, characterized in that at least one of the flow components (10, 10A to F) is a fluid monitoring component (12).

10. At least one of the fluid monitoring components (12) is - Pressure sensor (52), and - The fluid control device according to claim 9, characterized in that it is selected from a group of flow sensors.

11. The fluid control device according to claim 1, characterized in that the sheet structure (34) includes a plurality of sheet surface loops (64) separated by recesses (65), each sheet surface loop (64) forming a closed structure, and the high-pressure film (32) can form a seal thereon.

12. The fluid control device according to claim 1, characterized in that the pressure regulator (30, 30A to E) further has a pressure regulator flow path including a pressure regulating membrane (38) and a connecting channel (40) that passes from a high-pressure inlet (31) through the space between the high-pressure membrane (32) and the sheet structure (34) to a low-pressure outlet (39), and the first side of the pressure regulating membrane (38) is in fluid contact with the low-pressure outlet (39) of the pressure regulator flow path.

13. The fluid contact between the first side of the regulating pressure membrane (38) and the low-pressure outlet (39) of the pressure regulator flow path includes an outflow pressure cavity (41) in contact with the regulating pressure membrane (38), wherein the outflow pressure cavity (41) has a distance element (67) provided from the bottom (68) of the outflow pressure cavity (41), and the distance element (67) is configured to prevent the regulating pressure membrane (38) from reaching the bottom (68), the fluid control device according to claim 12.

14. The fluid control device according to claim 12, characterized in that the pressure regulator (30, 30A to E) further comprises a piston structure (36) connecting the high-pressure membrane (32) and the regulating pressure membrane (38), and a reference pressure chamber (37) is formed between the high-pressure membrane (32) and the regulating pressure membrane (38) and surrounds the piston structure (36).

15. The fluid control device according to claim 14, characterized in that the piston assembly (36) is positioned closer to the radially outer boundary of the high-pressure membrane (32) or the regulating pressure membrane (38) than to the radially inner boundary of the high-pressure membrane (32) or the regulating pressure membrane (38).

16. The area of ​​the regulating pressure membrane (38) located at a radius smaller than the radius of the piston assembly (36) is equal to the area of ​​the regulating pressure membrane (38) located at a radius larger than the radius of the piston assembly (36), and The fluid control device according to claim 15, characterized in that at least one of the following is true: the area of ​​the high-pressure membrane (32) located at a radius smaller than the radius of the piston structure (36) is equal to the area of ​​the high-pressure membrane (32) located at a radius larger than the radius of the piston structure (36).

17. The fluid control device according to claim 14, characterized in that the fluid connection (45b) between two flow components (10F, 10A) passes through the reference pressure chamber (37).

18. A fluid control device according to any one of claims 1 to 17, characterized in that it includes at least two pressure regulators (30, 30A to E), wherein the pressure regulators (30, 30A to E) have a high-pressure side and a low-pressure side.

19. The fluid control device according to claim 18, characterized in that the high-pressure sides of at least two pressure regulators (30, 30A to E) are provided on the first side of the fluid control device (1).

20. The fluid control device according to claim 18, characterized in that the high-pressure side of one of the at least two pressure regulators (30, 30A to E) and the low-pressure side of the other of the at least two pressure regulators (30, 30A to E) are provided on the first side of the fluid control device (1).

21. The fluid control device according to claim 1, characterized in that the inlet (2) to the fluid control device (1) is centered relative to the first flow component (10A).

22. The fluid control device according to claim 1, characterized in that the outlet (3) from the fluid control device (1) is centered relative to the first flow component (10A).

23. The fluid control device according to claim 1, characterized in that the inlet (2) to the fluid control device (1) is fluidly connected to the inlet (31) of the first flow component (10A).

24. The fluid control device according to claim 1, characterized in that the outlet (3) from the fluid control device (1) is centrally fluid-connected to the outlet (39) of the first flow component (10A).

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