Abstract:
A micro-valve for controlling fluid flows and a sealing device for sealing off cavities in a microfluid system, in particular in a lab-on-a-chip system, and also a method for the production thereof. A valve body or a sealing element bears with a sealing surface against a sealing surface of a substrate, the valve body or the sealing element is pressed with the sealing surface thereof in a fluid-tight manner against the sealing surface of the substrate by means of a pressure-exerting ring, and the pressure-exerting ring is cohesively connected to the substrate. The pressure-exerting ring and/or the valve body or the sealing element are at least partially elastic.

Description:
FIELD OF THE INVENTION 
     The invention concerns a microvalve for control of fluid streams and a sealing device for the sealing of cavities in a microfluidics system, especially in a lab-on-a-chip system as well as a method for its production. The microvalve has a substrate with a sealing surface and a valve body disposed movably relative to the substrate, which has a sealing surface and defines at least one channel for optional connection and/or separation of fluid lines in the substrate, wherein the sealing surface of the valve body and the sealing surface of the substrate lie against each other in a fluid-tight manner. The sealing device has a substrate with a sealing surface and a sealing element, having a sealing surface for sealing off a cavity in the substrate. The invention further relates to a sample processing chip with such a microvalve and/or such a sealing device. 
     A sample processing chip in the sense of this invention is a microfluidic system for chemical and biochemical analysis and/or synthesis, for example, for so-called point-of-care applications. These microfluidic systems are also termed lab-on-a-chip. 
     By sealing element in the sense of this invention is generally meant a nonpermeable element sealing off the cavity (channel, reservoir, chamber) from the surroundings of the substrate, or at least selectively sealing it off, e.g., for selected substances, especially a septum, a membrane, a filter element or the like. The sealing element can thus take on other functions in addition to the (selective) sealing function. For example, it can be air or gas-permeable for venting of the cavity. In contrast with the valve body, which given its function is movable relative to the substrate, the sealing element can be connected immovably to the substrate. 
     BACKGROUND OF THE INVENTION 
     Microvalves of the kind mentioned above are known. For example, reference is made to the patent application laid open DE 102 27 593 A1, the U.S. Pat. No. 6,748,975 B2 and the article “10-Way micro switching valve chip for multi-directional flow control”, Tadahiro Hasegawa et al, 7th International Conference on Miniaturized Chemical and Biochemical Analysis Systems, 5-9 Oct. 2003, Squaw Valley, Calif. USA. 
     From DE 102 27 593 A1, for example, there is known a microvalve, which has a substrate and a cover plate as valve body, which have contact surfaces lying against each other in fluid-tight contact and can be positioned relative to each other so that fluid lines can be optionally connected or separated. The microvalve is disclosed as being either a rotary valve with a cylindrical cover plate or a slide valve with a rectangular cover plate. Polymer materials and optionally composite materials are proposed preferably as the substrate and cover plate material. 
     The present invention deals with the question of how to create a simple and functionally reliable connection of the valve body and the sealing element to the substrate, as in such microvalves. Since the aforementioned microfluidics systems and especially the lab-on-a-chip systems are generally designed for onetime use, a low-cost solution is desirable. DE 102 27 593 A1 offers no clues for this. 
     In U.S. Pat. No. 6,748,975 B2 is disclosed a rotary valve, which is formed by a valve body (or rotor) which can turn relative to the substrate (or stator). The rotor can turn between two or more valve positions, in which one or more channels in the rotor optionally connects one or more inlet openings with one or more outlet openings, or separates these. The rotor lies by one contact surface on a corresponding contact surface of the stator. The position of the rotor with respect to the stator is defined by inserting the two elements in a valve housing, which besides the rotor and the stator includes various means for pressing on and activating the valve. Even though the rotor and the stator are loose parts in this case and seem suitable for onetime use, still a considerable expense is required to assembly the functional valve and thus the manipulation of the valve become more difficult. 
     A rotary valve consisting of a substrate and a rotating valve body is also pointed out in the aforementioned article by Hasegawa et al., which lie against each other by their contact surfaces. The valve body is formed from a silicone rubber ring with channels worked into it, which is pressed against the substrate by means of a mechanism consisting of at least four parts, including a pressing spring. Just how the pressing spring is buttressed against the substrate is not evident from the article. Here as well, it is to be assumed that an enclosing valve housing is provided, which receives the valve arrangement. 
     The inventor itself has already presented microvalve arrangements with a substrate  10  and a valve body  12  of the aforementioned kind at the conference “MipTec—The 9th International Conference and Exhibition on Drug Discovery” on 9 May 2006, as described hereafter by means of  FIG. 1 . The valve body  12  is in the form of an elastomer seal and is pressed by its contact or sealing surface  14  against a corresponding contact or sealing surface  16  of the substrate  10  via a valve cylinder  18 . The valve cylinder  18  is fashioned in the form of a plunger and has a pressing force applied to it by means of a compression spring  20 . The compression spring  20  in turn thrusts against a housing  22 , which is screwed directly onto the substrate  10  by means of a screw connection  24 . The microvalve arrangement of  FIG. 1  is of simple construction when compared to the aforesaid prior art, yet still a multitude of different materials and components are needed and the onetime assembly is still too elaborate in practice for a mass production. 
     SUMMARY OF THE INVENTION 
     The problem of the present invention, accordingly, is to improve a microvalve as well as a sealing device of the aforementioned kind so that it can be produced with low effort and thus with low costs. Accordingly, the problem of the invention is to provide a method for the production of such a microvalve or a corresponding cover device that is more economical and thus suited for the mass production of disposable products. 
     The problem is solved by a microvalve with a substrate having a sealing surface, and a valve body arranged movably relative to the substrate, having a sealing surface and defining at least one channel for the optional joining and/or separating of fluid lines in the substrate, wherein the sealing surface of the valve body and the sealing surface of the substrate lie fluid-tight against each other, wherein the valve body is pressed by means of a pressing ring joined by a material connection to the substrate against the sealing surface of the substrate by its sealing surface and the pressing ring and/or the valve body is at least partly elastic, a sealing device with a substrate having a sealing surface, and a sealing element, having a sealing surface for sealing a cavity in the substrate, wherein the sealing element is pressed by means of a pressing ring joined by material connection to the substrate fluid-tight against the sealing surface of the substrate by its sealing surface and the pressing ring and/or the sealing element is at least partly elastic, as well as a method for making a microvalve or a sealing device in a microfluidics system, especially in a lab-on-a-chip system, wherein a valve body or a sealing element with a sealing surface is placed on a sealing surface of a substrate, the valve body or the sealing element is pressed by means of a pressing ring fluid-tight against the sealing surface of the substrate by its sealing surface, and the pressing ring is joined to the substrate by a material connection. Advantageous modifications of the invention are the subject of the subclaims. 
     In the microvalve according to the invention, the valve body is pressed by its sealing surface in form-fitting manner against the sealing surface of the substrate by means of a pressing ring joined in a material connection to the substrate and the pressing ring and/or the valve body is at least partly elastic. 
     The inventors have discovered that the construction of the microvalve according to the invention is likewise suitable for simple and economically favorable assembly of other sealing elements with sealing function. In a sealing device according to the invention for the sealing of cavities with a sealing element of the kind described above, the sealing element is pressed by its sealing surface against the sealing surface of the substrate by means of a pressing ring joined by a material connection to the substrate in fluid-tight manner, while the pressing ring and/or the sealing element are at least partially elastic. 
     The method according to the invention for production of the microvalve or the sealing device in a microfluidics system, especially in a lab-on-a-chip system, calls for placing a valve body or a sealing element with a sealing surface on a sealing surface of a substrate, pressing the valve body or the sealing element by its sealing surface fluid-tight against the sealing surface of the substrate by means of a pressing ring, and joining the pressing ring by a material connection to the substrate. 
     While thus far the only valve arrangements known are those assembled from at least six individual parts and needing to be assembled in a corresponding number of individual steps, only three parts are provided for the microvalve of the invention or for the sealing device of the invention, namely, the substrate, the valve body and the pressing ring. These three elements are put together in a simple work step, in which they are stacked one on the other and fixed by a material connection between the pressing ring and the substrate. Here, the pressing ring and/or the valve body or the sealing element functionally replace the spring. The pressing ring, which supports the valve body or the sealing element relative to the substrate on its side away from the sealing surface, also functionally replaces the much more complicated to fabricate housing. The pressing ring can be made as a simple injection molded part, or a plastic extrusion-coated metal or stamped part (e.g., of spring plate). The valve body can also be made as a simple part, such as a disk-shaped part, in one or at least a few work steps. The microvalve of the invention and the sealing device of the invention totally do without the use of a spring to generate the pressing force. For this purpose, the invention makes use of the (partial) elasticity of the valve body or sealing element and/or the pressing ring. For this there needs to be a suitable choice of material for the valve body or the sealing element and/or the pressing ring, taking into account the geometry of the particular structural part, so that a sufficient elasticity and, thus, pressing force is assured for the sealing. 
     In one advantageous modification, the valve body or the sealing element is compressive-elastic. Alternatively or additionally, the pressing ring is flexural-elastic, at least for a segment. 
     The former can be achieved preferentially in that the valve body or the sealing element consists at least partly of an elastomer. Especially suitable materials are thermoplastic elastomers, silicones, fluoroelastomers such as Viton®, ethylene-propylene-diene rubber, styrene-butadiene rubber (SBR), ethylene-propylene rubber (EPM) or nitrile rubber. 
     The latter can be achieved preferentially in that the pressing ring consists of an injection-molded partly elastic plastic or a plastic extrusion-coated spring steel. Specially suitable plastics are thermoplasts and duroplasts, especially acrylonitrile-butadiene-styrene copolymerizate (ABS), polyoxymethylene (POM), polyether ketones (PEEK). 
     Especially preferably, the valve body has a shape-stable part and an elastomer seal, on which the sealing surface is formed, whereby a pressing force from the pressing ring acts across the shape-stable part on the elastomer seal. 
     The shape-stable part ensures a uniform distribution of the pressing force over the entire sealing surface of the elastomer seal, while the latter due to its elasticity is compressed and provides a sufficient sealing. 
     In one advantageous modification, the shape-stable part together with the elastomer seal is produced by two-component injection molding. 
     In this way, the shape-stable part, which in this embodiment preferably consists of a shape-stable plastic, and the elastomer seal are combined into a single valve body, which reduces the assembly expense. Also, the production of a two-component injection-molded part is relatively economical. 
     Advantageously, the at least one channel in the elastomer seal is formed as a through opening. 
     This embodiment of the invention has the advantage of easy workmanship. Channels in the form of depressions or grooves, if the valve body is not finished by injection molding, are produced or added subsequently in familiar fashion by etching, laser ablation, spray engraving, hot engraving, milling or the like. On the other hand, the channel in the form of a through opening can be produced in a single stamping process and a valve body with such an elastomer seal is therefore more favorable. 
     This sealing element in one preferred embodiment is joined by a material connection to the pressing ring. This embodiment can be achieved, for example, by a joint production of both elements in a two-component injection molding process or by subsequent gluing of the two elements and it facilitates the assembly process. 
     The microvalve can preferably be fashioned as a rotary valve or a slide valve. 
     The material connection between the substrate and the pressing ring in the microvalve of the invention or the sealing device of the invention is preferably created by a welding connection. Again preferably, the pressing ring and the substrate are joined together by ultrasound welding or by laser welding. Ultrasound welding has the advantage that the parts being joined are pressed together in a defined position and fixed precisely in this arrangement. 
     In an especially preferred embodiment of the microvalve or the sealing device, the sample processing chip forms the substrate. 
     The microvalve or the sealing device on account of their simple makeup are easy to miniaturize. The functional components of valve and/or sealing device can therefore be arranged with higher density on the microfluidic chip. It is also possible to use both sides of a chip for mounting. In this way, even higher integration densities and more complex channel structures and thus an improved functionality can be achieved for the same footprint on a chip. 
     The microvalve or sealing device of the invention, especially when combined with a recessed seat, can be integrated fully in the sample processing chip when the valve seat or the seat for the sealing element is worked so deep in the form of a recess into the sample processing chip that the valve body can be set fully in the processing chip. Moreover, the a recess or depression can also be provided for the pressing ring in the sample processing chip, enabling a flush closure of the pressing ring with the surface of the sample processing chip. In this way, the integration density of the functional components is further increased and the chip is given a flat profile, even when the functional components of valve and/or sealing device are mounted on both sides. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further problems, features and benefits of the invention will now be explained more closely by means of sample embodiments with the help of the drawings. There are shown: 
         FIG. 1 , a microvalve of familiar design; 
         FIG. 2 , a sample processing chip with the valve of the invention in three views; 
         FIG. 3 , three sectional views of a first embodiment of the microvalve of the invention; 
         FIG. 4 , three sectional views of a second embodiment of the microvalve of the invention; 
         FIG. 5 , three sectional views of a third embodiment of the microvalve of the invention, and 
         FIG. 6 , two sectional views of a sample embodiment of the sealing device of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 2  shows a sample processing chip  210  according to the invention in three views, which at the same time constitutes the substrate for five microvalves  212  of the invented kind. The microvalves  212  are configured as rotary valves. In this embodiment, they have an elastomer seal  214  and a shape-stable part  216 , which together form the valve body. The valve body is forced by means of a pressing ring  218  against a base and sealing surface  220  in the valve seat in the substrate  210 . The valve seat is fashioned as a stepped cylindrical hollow in the substrate  210 . The deeper step of the hollow forms the actual valve seat with the sealing surface  220 . The shallower hollow with larger diameter forms the seat for the pressing ring  212 , so that the entire installation consisting of valve body and pressing ring closes off the surface of the substrate  210  flush. At the bottom of  FIG. 2  one notices that fluid lines  222  extend through the substrate  210 , which empty into the valve seat in general and into the sealing surface  220  of the valve seat in the specifically illustrated example. The function of the valve body is to optionally join or separate these emptying points. For this purpose, at least one or more channels are provided at least in the elastomer seal  214  in the valve body, in the embodiment shown, which communicate for example with none, with one, two or all three emptying points, depending on the position of the valve. 
     The sample embodiment shown in  FIG. 2  is to be taken only as a sample embodiment. Of course, the invention also covers valves that have more or fewer emptying points. In particular, it also covers those sealing devices that have only a single emptying point or cavity in the region of the sealing surface. In departure from the embodiment shown, the lines  222  can also empty laterally (radially in regard to the valve axis) into the valve seat, for example. 
       FIGS. 3A-3C  show in enlarged view a section through a sample embodiment of the microvalve of the invention, namely, in sequence, an exploded view ( FIG. 3A ), an assembled view in a first valve position ( FIG. 3B ) and an assembled view in a second valve position ( FIG. 3C ). Furthermore, the valve positions are also illustrated in top view in the details of  FIGS. 3B and 3C . 
     The sample processing chip  310  is shown only in a segment. It consists of a rather substantial support plate  324 , in which the valve seat  326  is made from the top side and the fluid lines  322  from the lower side. The sample processing chip  310 , furthermore, is closed with a film  328  from the lower side. 
     The valve seat  326  is made in the form of a two-step shallow borehole in the support plate  324 . The lower step  330  forms the actual valve seat with the base and sealing surface  320 . The upper step  332  forms the seat for the pressing ring  318 . 
     The valve body  334 , as described above, is assembled from a shape-stable part  316  and an elastomer seal  314 . The elastomer seal  314  has a sealing surface  336  on its lower side, by which it lies in the assembled condition on the sealing surface  320  of the substrate  310  or the support plate  324 . In the elastomer seal  314 , a channel  338  is provided for the optional connecting or separating of the fluid lines  322  depending on valve position. In  FIG. 3B  the horizontal valve position is shown, in which the fluid lines  322  are joined to each other by the channel  338 ; in  FIG. 3C  the vertical or blocking position of the valve is shown, in which the fluid lines  322  are not connected by the channel  338 . The channel  338  in this embodiment is fashioned entirely in the elastomer seal  314  as a depression. The shape-stable part  316  of the valve body  334  is flat on its lower side and does not make contact with the fluid. 
     The elastomer seal  314  provides the needed elasticity and thus compressibility of the valve body  334 , so that this can be pressed with sufficient strength by means of the pressing ring  318  in the assembled condition against the sealing surface  320  so that the contact surfaces  336 ,  320  lie fluid-tight against each other. On the other hand, the pressure should not be so strong that the resulting friction between the two contact surfaces makes it impossible for the valve body  334  to rotate under reasonable expenditure of force. The latter can be achieved by an appropriately adjusted excess thickness of the valve body as compared to the depth t of the actual valve seat  330 . 
     The material connection between the pressing ring  318  and the substrate  310  or the support plate  324  according to the invention is achieved in this sample embodiment by ultrasound welding. For this purpose, the pressing ring  318  has a ring-shaped shoulder  340  on its lower side, whose material enters into a material connection with the material of the support plate  324  during the ultrasound welding. 
     The valve body  334  and more precisely the shape-stable part  316  of the valve body  334  has at its upper end a cylindrical shoulder  342 , which is introduced into a corresponding borehole  344  in the pressing ring  318 . The dimensions of the shoulder  342  in relation to the outer diameter of the valve body  334  and thus the upper annular surface of the shape-stable part  316 , allowing for the material composition, determine the frictional force between the valve body  334  and the pressing ring  318 . In the cylindrical shoulder  342  there is provided a recess  346 , serving as a handle for activating the rotary valve  312 . The recess can be fashioned, for example, in the form of a hexagonal socket or the like for activation by means of an appropriate screwdriver. 
     In  FIGS. 4A  to C is shown a second sample embodiment of the invented microvalve, which is essentially distinguished by a different form of the valve body  434 , in that although it is assembled in two pieces from a shape-stable part  416  and an elastomer seal  414 , the elastomer seal  414  has less structural height and the channel  438  is fashioned as a through opening in the elastomer seal  414 . Such an elastomer seal can be made in simple fashion by punching out from a band of material. The channel  438  furthermore extends partly into the shape-stable part  416 , so as to provide on the whole an adequate cross section for the joining of the two fluid lines  422  in the substrate (only the massive support plate  424  is shown in  FIG. 4 ). 
     Another difference regarding the valve body  434  is that the shape-stable part  416  also has on its lower side a recess  448  to partially receive the elastomer seal  414 . This is advantageous in cases where the elastomer seal  414  has a slight cross if only in one section, as is depicted in  FIGS. 4A and 4B . The recess  448  serves here as a guide or to stabilize the elastomer seal  414 , which due to its elasticity might otherwise get shifted, skewed, or even destroyed when the valve is activated. 
     The shape-stable part  414  again has a cylindrical shoulder  442 , which fits into a corresponding central borehole  444  in the pressing ring  418 . The shoulder  442  has a larger diameter in this sample embodiment and a recess  446  on its top side, which is arranged off center to the center axis Z. The recess  446 , as in the example of  FIG. 3 , serves to activate the rotary valve  412 , but in this case it can be activated as a recessed grip, with the finger, for example. 
       FIGS. 5A to 5C  show another sample embodiment of the invented microvalve, which in contrast with the two previous ones is configured not as a rotary valve, but rather a sliding valve  512 . Accordingly, all parts of the valve  512 , namely, the pressing ring  518 , the shape-stable part  516  of the valve body  534 , the elastomer seal  514  and also the valve seat  526  in the support plate  524  of the substrate  510 , are designed for a translatory movement of the valve body  534 . 
     Even though a channel  538  is also fashioned here as a through opening in the elastomer seal  514 , unlike the sample embodiment of  FIG. 4  the channel  538  does not extend into the shape-stable part  516 . The lower side of the shape-stable part  516  of the valve body has only an outer peripheral edge  550  to stabilize or guide the elastomer seal  514 . In this case, there is no inner circumferential edge that would also constitute a limit for the channel  538 . 
     The elastomer seal  514  in the valve position shown in  FIG. 5B  closes by its sealing surface  536  the right fluid line  522 . Thus, only the left fluid line  522  has a connection to the channel  538 . A communication of the two fluid lines does not occur. On the contrary, in the valve position per  FIG. 5C , the two fluid lines  522  are joined to each other by the channel  538 . 
     The pressing ring  518 , as can be seen from  FIG. 5C , has a rectangular outer contour with rounded corners. Optionally, however, the pressing ring can also have a round outer contour in a sliding valve, where the elongated groovelike recess  544  preferably has parallel sides in the activating direction for better guiding of the valve body  534 . 
     In  FIGS. 6A to 6C , a sample embodiment of the invented sealing device  612  is shown, with a substrate  610 , a sealing element  660  and a pressing ring  618 . The substrate  610 , as in the preceding sample embodiments, constructed from a support plate  624 , in which are made the seat  626  for the sealing element  660  from the top side and a fluid line  622  from the lower side, as well as a film  628  to seal the support plate  624  from the lower side. The fluid line  622  empties in the form of a wide cavity  662  through the base and sealing surface  620  into the actual seat  630  for the sealing element  660 . The sealing element  660  seals off the cavity  662  at the top side by pressing it with its lower sealing surface  636  via the pressing ring  618  against the sealing surface  620  in the assembled state, see  FIG. 6B . 
     In the sample embodiment of  FIG. 6 , the sealing element  660  is configured as fully elastic material, i.e., as a single piece of elastomer. The elasticity to achieve the pressing force needed for a sealing is therefore provided solely from the sealing element  660 . The pressing ring  618  is sufficiently stiff to buttress the sealing element  660  against the support plate  624 . 
     The pressing ring  618  has a central borehole  644 , enabling access to the sealing element  660 , for example, acting as a septum for removal of fluid from the cavity  662  by means of a cannula from the outside. 
     In terms of providing the pressing force, all sample embodiments shown are identical in that the necessary elasticity is provided only by the valve body or the sealing element and not by the pressing ring. The valve bodies of  FIGS. 3, 4 and 5  differ from the sealing device of  FIG. 6  in that the elasticity in these cases is provided by only a part of the valve body, namely, the elastomer seal, while the shape-stable part and the pressing ring in all three sample embodiments are so stiff that they do not yield significantly under the pressing force. The shape-stable part of the valve body ensures that the pressing force is uniformly distributed over the elastomer seal. 
     In departure from the sample embodiments shown, however, a portion of the elasticity can also be provided by the pressing ring, in that this is designed in terms of its material and geometry according to the elasticity requirements, so that it can partly yield when a force is exerted. Thus, the elasticity-related restoring force can be distributed among the valve body or the sealing element and the pressing ring. 
     In departure from the sample embodiments shown, it is furthermore possible, similar to the configuration of  FIG. 6 , to configure the valve body as a single fully elastic element, provided that it has enough natural stability to fulfill the desired sealing function. For example, in the form of a ceramic filter, the sealing element can also be inelastic. In this case, the required elasticity to generate a sufficient pressing force comes solely from the pressing ring. The same holds in theory for the valve body. 
     In all sample embodiments shown, an embodiment is chosen in which the material connection between the pressing ring and the support plate of the substrate is created by means of ultrasound welding. But the invention likewise applies to embodiments in which the material connection is achieved, e.g., by gluing, solvent gluing, laser welding or other forms of welding. 
     The shape-stable part and the elastomer seal can basically be joined by form-fit, friction connection, and material connection. As already mentioned, both parts of the valve body can be produced in a joint two-component injection molding. Alternatively, they can be produced separately and glued together. In departure from the sample embodiments depicted, a form fit can also be achieved by dogs in the form of projections on the shape-stable part, which engage with corresponding recesses in the elastomer seal or vice versa. 
     LIST OF REFERENCE NUMBERS 
     
         
           10  Substrate/sample processing chip 
           12  Elastomer seal 
           14  Sealing surface 
           16  Sealing surface 
           18  Valve cylinder 
           20  Compression spring 
           22  Valve housing 
           24  Screw/screw connection 
           210  Substrate/sample processing chip 
           212  Microvalve 
           214  Elastomer seal 
           216  Shape-stable part of valve body 
           218  Pressing ring 
           220  Sealing surface 
           222  (Fluid) line 
           310  Substrate/sample processing chip 
           312  Microvalve 
           314  Elastomer seal 
           316  Shape-stable part of valve body 
           318  Pressing ring 
           320  Sealing surface 
           322  (Fluid) line 
           324  Support plate 
           326  Valve seat 
           328  Film 
           330  Lower step, valve seat proper 
           332  Upper step, seat 
           334  Valve body 
           336  Sealing surface 
           338  Channel 
           340  Ring-shaped shoulder 
           342  Cylindrical shoulder 
           344  Borehole 
           346  Recess 
           410  Substrate/sample processing chip 
           412  Microvalve 
           414  Elastomer seal 
           416  Shape-stable part of valve body 
           418  Pressing ring 
           422  (Fluid) line 
           424  Support plate 
           434  Valve body 
           438  Channel 
           442  Cylindrical shoulder 
           444  Borehole 
           446  Recess 
           448  Recess/seat 
           510  Substrate/sample processing chip 
           512  Microvalve 
           514  Elastomer seal 
           516  Shape-stable part of valve body 
           518  Pressing ring 
           522  (Fluid) line 
           524  Support plate 
           526  Valve seat 
           534  Valve body 
           536  Sealing surface 
           538  Channel 
           544  Borehole 
           550  Outer peripheral edge 
           610  Substrate/sample processing chip 
           612  Sealing device 
           618  Pressing ring 
           620  Sealing surface 
           622  (Fluid) line 
           624  Support plate 
           626  Valve seat 
           628  Film 
           630  Valve seat proper 
           636  Sealing surface 
           644  Borehole 
           660  Sealing element 
           662  Cavity 
         Z Center axis