High-pressure viewing cell for microfluid applications

Abstract

The invention relates to a high-pressure viewing cell (1) for visual observation of a sample, in particular a microfluidic chip (2), wherein the sample can be arranged in a sample-receiving space (3) of the high-pressure viewing cell (1), wherein the high-pressure viewing cell (1) has a window element (5) for observing the sample through the window element (5) and a window-element holder (7) for holding the window element (5). To achieve a high level of operational capability, it is provided that, for the purpose of establishing a connection, in particular an interlocking and / or frictional connection, between the window-element holder (7) and the window element (5), the window element (5) is formed such that it at least partly tapers from an interior-pressure side of the window element (5) to an exterior-pressure side of the window element (5).

Description

[0001] High-pressure viewing cell for microfluidic applications

[0002] The invention relates to a high-pressure viewing cell for optically observing a sample, in particular a microfluidic chip, wherein the sample can be arranged in a sample receiving space of the high-pressure viewing cell, wherein the high-pressure viewing cell has a window element for observing the sample through the window element and a window element holder for holding the window element.

[0003] To investigate the flow behavior of a fluid medium in the rock of underground deposits, it is known to simulate the rock structure of the rock using a microfluidic chip, wherein a microfluidic channel system of the microfluidic chip is configured to correspond to the rock porosity or a rock channel system of the rock. For this purpose, the microfluidic chip is typically held by a holding device, and a test fluid, usually corresponding to the fluid medium, is introduced into the microfluidic channel system via a fluid inlet of the microfluidic chip in order to investigate the flow behavior of the test fluid in the microfluidic channel system, usually under microscopic observation.For example, in an exploration for oil extraction from rock, oil can first be introduced into the microfluidic channel system, and then water can be introduced into the microfluidic channel system to investigate the possibility of extracting the oil from the rock. The microfluidic chip is typically designed to be light-transmissive, allowing the flow behavior of the test fluid in the microfluidic channel system to be observed with a microscope by light illuminating the microfluidic chip.

[0004] To investigate the flow behavior of the test fluid under high-pressure conditions, frequently at a test fluid pressure of several hundred bar, the holding device with the microfluidic chip is typically arranged in a receiving chamber of a high-pressure viewing cell. The receiving chamber is filled with a filling fluid, usually water, and a filling fluid pressure is set in the filling fluid corresponding to the test fluid pressure. In this way, a load exerted on a structure of the microfluidic chip by the test fluid pressure can be largely compensated by the filling fluid pressure to maintain the structural integrity of the microfluidic chip.The high-pressure viewing cell typically has a cuboid window element held by a window element holder of the high-pressure viewing cell. This allows the flow behavior of the test fluid in the microfluidic channel system to be observed with a microscope from an external pressure side of the window element through the window element. To hold the window element, the window element holder typically has an annular support element that rests on an outer surface of the window element, with the support element applying a pressing force to the window element.

[0005] This is where the invention comes in. The object of the invention is to provide a high-pressure viewing cell of the type mentioned above, which has a high degree of usability, particularly with regard to optical observation of a sample, in particular a microfluidic chip or a test fluid in a microfluidic channel system of the microfluidic chip.

[0006] The object is achieved according to the invention in that, in a high-pressure viewing cell of the type mentioned at the outset, for producing a connection, in particular a positive and / or non-positive connection, between the window element holder and the window element, the window element is tapered at least in sections, in particular predominantly, from an internal pressure side of the window element to an external pressure side of the window element.

[0007] It has been shown that during an optical examination of the sample, in particular of a microfluidic chip or of an examination fluid in a microfluidic channel system of the microfluidic chip, usually with a microscope through a window element of a high-pressure viewing cell, a reduction in the working distance of the microscope or an approach of the microscope to the window element is generally limited by a window element holder holding the window element, in particular a support element of the window element holder, which support element is arranged on the outside in front of the window element. This usually represents a limitation for the quality of the optical examination or of an optical image with the microscope. The basis of the invention is the idea of ​​implementing an embodiment of an arrangement of the window element with the window element holder in such a way that a greater approach of an optical measuring device orMicroscope is mounted on the outside of the window element or a working distance of the optical measuring device or

[0008] microscope can be reduced.

[0009] By designing the window element to taper at least partially, in particular predominantly, preferably substantially, from an internal pressure side of the window element to an external pressure side of the window element or in an outward direction of the window element, the window element can be held with the window element holder, in particular in a form-fitting and / or force-fitting manner, in such a way that a high degree of free space can be achieved in front of the window element on the external pressure side or a distance between an optical measuring device, in particular a microscope, arranged in an insert in front of the window element on the external pressure side for measuring through the window element and the window element can be reduced. This makes it possible to increase the quality of the measurement, in particular the microscopic measurement. In particular, a high resolution or a large numerical aperture of the optical measurement, in particular the microscopic measurement, can be implemented.This is particularly relevant when microstructures are to be observed under high pressure. This is especially true when the sample is a microfluidic chip or a fluid in a microfluidic channel system of a microfluidic chip.

[0010] Typically, an internal pressure refers to a pressure in the sample receiving chamber of the high-pressure viewing cell, in particular a filling fluid pressure of a filling fluid with which the sample receiving chamber can be filled when the high-pressure viewing cell is in use. During use, the internal pressure side of the window element is usually loaded with the filling fluid pressure, or the external pressure side of the window element is loaded with an external pressure of an environment outside the sample receiving chamber. During use, an optical measurement or observation of the sample is usually carried out through the window element. The internal pressure is usually greater than 100 bar. The internal pressure is usually from 100 bar to 4000 bar, in particular from 250 bar to 1000 bar.

[0011] Typically, an external pressure refers to a pressure outside the sample receiving chamber, in particular to an external pressure or ambient pressure around the high-pressure viewing cell when the high-pressure viewing cell is in use. The external pressure or ambient pressure is generally less than 5 bar, in particular between 0.5 bar and 2 bar. In particular, the high-pressure viewing cell is designed for use at such pressures. The internal pressure side or inside, in particular of the window element, usually refers to a side facing the sample receiving chamber, in particular of the window element. The external pressure side or outside, in particular of the window element, usually refers to a side facing away from the sample receiving chamber, in particular of the window element. The internal pressure side and external pressure side of the window element are usually opposite each other on the window element.The window element and / or the window element holder are usually part of a sample receiving chamber.

[0012] Sample chamber wall of the sample chamber. Typically, the window element, particularly an inner transparent surface of the window element, borders the sample chamber. The outer direction of the window element is typically oriented from the inner pressure side to the outer pressure side of the window element.

[0013] The window element holder typically has a support element. It is advantageous if the window element holder, in particular the support element, positively defines the window element at a side surface of the window element, which side surface extends between an inner transparent surface of the window element facing the sample receiving chamber and an outer transparent surface of the window element located outside the sample receiving chamber. The support element typically forms a stop for the window element, in particular the side surface of the window element, in the outward direction of the window element. The side surface of the window element is typically pressed against the support element. In particular, the window element can thereby be held laterally by the window element holder.In particular, this makes it possible to hold the window element with the window element holder on the outside in front of the window element, in particular the outside see-through surface, with reduced space requirements due to the window element holder. The respective see-through surface is usually a surface area of ​​the window element through which the sample can be observed during use. Expediently, the inside see-through surface and / or the outside see-through surface can be essentially flat. The outward direction of the window element is usually oriented essentially orthogonal to the inside see-through surface and / or the outside see-through surface. The window element can have a see-through direction in which, during use, the sample can be observed through the window element from outside the sample receiving space. The outward direction can be oriented opposite to the see-through direction.When viewed from the opposite direction of the window element's outward direction, the side surface typically extends circumferentially around the window element. Typically, the window element and the window element holder are connected to each other in a form-fitting and / or force-fitting manner. The window element and the window element holder are generally connected to each other in a fluid-tight manner. For this purpose, the high-pressure viewing cell can have one or more sealing elements arranged between the window element and the window element holder, in particular between adjacent surfaces of the latter.

[0014] The window element can have, at least in sections, a side contour tapering in the outward direction in a first cross-section through the window element running parallel to the outward direction of the window element. The window element can have, at least in sections, a side contour tapering in the outward direction in a second cross-section through the window element running parallel to the outward direction of the window element and oriented orthogonally to the first cross-section. The respective side contour is usually formed with, in particular by, the side surface. It is advantageous if the tapered side contour extends over more than 50%, in particular more than 75%, of an average height of the window element in the outward direction of the window element.A high level of robustness can be achieved if, in the respective cross-section, the window element has a first section which, in the outward direction, is positioned in front of a second section with the, in particular, aforementioned, tapered side contour, wherein the first section has side contour lines oriented substantially parallel to one another. Typically, the side contour lines of the first section adjoin on the inside an inner contour line facing the sample receiving space, in particular representing the inner transparent surface. It is advantageous if the first section, in particular its side contour lines, extend over more than 2%, in particular more than 5%, of an average height of the window element in the outward direction of the window element.Typically, in the respective cross-section, the particularly tapered side contour refers to side contour lines of the window element that are opposite one another with respect to a center axis oriented in the outward direction. It has proven useful if the side surface is designed at least in sections, in particular predominantly, preferably substantially, as a rotational surface, in particular a conical surface, that tapers in the outward direction of the window element. The outward direction typically runs from the internal pressure side of the window element to the external pressure side of the window element. The outward direction can be oriented opposite to the viewing direction of the window element. An axis of rotation of the rotational surface is typically parallel to the outward direction of the window element and preferably runs through a center of the window element.

[0015] It is advantageous if the window element holder, in particular the support element, forms a through-channel into which the window element is at least partially, preferably substantially entirely, inserted in a form-fitting manner. The window element is usually at least partially inserted into the through-channel in the outward direction of the window element. The support element usually forms a stop for the window element, in particular the side surface, in the outward direction of the window element. A through-channel wall forming the through-channel wall is usually designed to correspond in shape to the side surface of the window element. The window element is usually inserted into the through-channel in such a way that the side surface is pressed against the through-channel wall. In this way, a robust fixation of the window element can be implemented.The through-channel, in particular the through-channel wall, usually extends entirely through the support element. A contact surface, at which the side surface and the through-channel wall adjoin one another, in particular contact one another, and are usually pressed against one another, can expediently extend substantially circumferentially around the window element. This applies in particular when viewed from the opposite direction to the outward direction of the window element. It has proven advantageous if the contact surface is designed, at least in sections, preferably substantially, as a rotational surface, in particular a conical surface, tapering in the outward direction of the window element. An axis of rotation of the rotational surface is usually substantially parallel to the outward direction of the window element.The through-opening wall can form a, in particular sleeve-shaped, window element receptacle into which the window element is at least partially, in particular substantially entirely, inserted in the outward direction of the window element, forming a positive connection in the outward direction. The window element receptacle or through-opening wall is usually designed to correspond in shape to the side surface of the window element. A channel axis running from an inside opening of the through-channel to an outside opening of the through-channel is usually oriented substantially parallel to the outward direction. The window element is usually at least partially inserted into the through-channel through the inside opening of the through-channel.

[0016] It is practical if the window element holder has a pressing surface, in particular formed with an elastically and / or plastically deformable sealing material, wherein the side surface is pressed against the pressing surface in order to implement a fluid-tight press connection or to connect the window element and the window element holder to one another in a fluid-tight manner. The sealing material can be formed, for example, with, in particular from, an elastomer, for example rubber. The pressing surface can be implemented as part of the support element, in particular as part of the through-channel wall or arranged on it. The pressing surface can be formed with one or more sealing elements. The sealing element can, for example, be a sealing ring, in particular made of an aforementioned sealing material.The sealing element can be partially inserted, usually in a form-fitting manner, into a recess in the support element, in particular in the through-channel wall, which recess is configured to correspond in shape to the sealing element. Typically, the pressing surface is arranged circumferentially around the window element, particularly along the side surface, particularly when viewed against the outward direction of the window element. Typically, the support element circumferentially surrounds the window element on the lateral side, with the support element forming a stop for the window element in the outward direction of the window element.

[0017] It is advantageous if the window element holder has an actuating device in order to press the window element against the window element holder, in particular against the support element, upon actuation of the actuating device and / or to change a pressing force between the window element, in particular the support element, and the window element holder. The actuating device can have an actuating element that is movable relative to the support element, in particular in order to exert a pressing force on the window element with the actuating element upon actuation of the actuating device, so that the window element is pressed against the support element. In particular, upon actuation of the actuating device, the side surface of the window element can be pressed against the through-channel wall, in particular the pressing surface, and / or a pressing force between the side surface and the through-channel wall can be changed.It is advantageous if the actuating device, in particular the actuating element, forms a stop, in particular a movable stop, for the window element counter to the outward direction of the window element. This can expediently be a movable stop for a surface of the window element facing the sample receiving chamber of the high-pressure viewing cell, in particular the internal pressure side.

[0018] It is practical for the window element holder to be detachably connected to a basic structure of the high-pressure viewing cell, wherein the window element holder can be detachable from the basic structure without releasing the connection, in particular the force-fitting connection, in particular a press connection, and / or positive connection, between the window element holder and the window element. In particular, this can be done without releasing a pressing of the window element, in particular the side surface of the window element, against the support element, in particular the through-channel wall. The window element holder can expediently have a closure element movable relative to the support element, in particular with which closure element the window element is detachably enclosed in the through-channel. The closure element can form a detachable stop for the window element, which prevents the window element from becoming detachable from the through-channel.It is expedient if the closure element at least partially closes the through-channel to prevent removal of the window element from the through-channel, usually on a side of the window element facing the sample receiving space. The closure element can be detachably connected to the support element, in particular in a force-fitting and / or form-fitting manner, usually with a connecting device, for example a screw connection, of the window element holder. The closure element can be partially or substantially entirely inserted into the through-channel, in particular via a through-channel opening of the through-channel facing the sample receiving space. It is practical if the closure element is reversibly screwed into the support element, in particular into the through-channel, with a thread.For example, the closure element can be a threaded ring that can be screwed into the through-channel wall, particularly in a direction of extension of the through-channel. For this purpose, a surface of the through-channel wall can have a mating thread corresponding to a thread of the threaded ring. The closure element can be the actuating element. The closure element and the actuating element can be different parts. The closure element and the support element can form two separate parts. The basic structure can be formed with one or more sample receiving chamber walls, with the sample receiving chamber typically being formed by connecting the basic structure and the window element holder including the window element.

[0019] It is practical if the window element holder is detachably connected to a base structure of the high-pressure viewing cell, wherein the window element holder is pressed against the base structure, in particular against a mating surface of the base structure, by means of a fastening element, in particular one that runs circumferentially around the window element holder. This is usually done by forming a positive connection between the window element holder and the fastening element. The fastening element can be connected to the base structure by means of a screw connection of the high-pressure viewing cell, in particular of the fastening element and / or the base structure. Preferably, the fastening element is connected to the base structure by screwing in the fastening element, wherein, for example, a thread of the fastening element, in particular one that runs circumferentially around the fastening element, is screwed into a mating thread of the base structure.The fastening element can expediently be coupled to the base structure in such a way that a pressing force exerted by the fastening element on the window element holder can be changed, in particular adjusted, for example, with the screw connection, in particular by screwing in the fastening element. The fastening element can extend circumferentially around the window element holder in order to apply a pressing force to the window element holder along a circumference of the window element holder with the fastening element. For example, the fastening element can be a fastening sleeve, wherein the fastening sleeve circumferentially encloses the window element holder, in particular in a form-fitting manner.The window element holder can expediently have a recess and the fastening element can have a projection that is designed, in particular, to correspond in shape to the recess, wherein the projection is at least partially inserted into the recess such that the projection forms a stop for a recess surface of the recess in the outward direction of the window element. The recess is usually arranged on an outer surface of the window element holder. The recess surface can form a contact pressure area via which a pressing force is applied to the window element holder by means of the fastening element, in particular the projection, for pressing the window element holder against the counter surface. The fastening element can have a plurality of projections, each of which is at least partially inserted into at least one recess.It has proven effective if the recess is implemented with a stepped edge region of the window element holder, in particular as a stepped edge region, wherein the stepped edge region forms a, in particular flat, stepped surface, against which the projection of the fastening element engages, forming a stop in the outward direction. The stepped edge region can be formed in a radial direction. The radial direction can refer to a circumference around the window element, which circumference usually lies in a plane transverse, in particular orthogonal, to the outward direction. The stepped surface can be formed by an edge-side recess of the fastening element.

[0020] Typically, the window element holder has a contact surface which is pressed against a mating surface of the base structure to connect the window element holder and the base structure. An interface formed by the contact surface and the mating surface, at which the contact surface and the mating surface adjoin one another, can be formed with a sealing element, in particular a sealing ring, in order to implement a fluid-tight connection between the contact surface and the mating surface. The sealing element can be partially arranged in a form-fitting manner in a recess in the contact surface and / or the mating surface, the shape of which corresponds to the sealing element. The sealing element can be designed analogously to that described above, in particular with an elastically and / or plastically deformable sealing material.

[0021] It is advantageous if the window element holder does not overlap the outer viewing area. It has proven effective if, in a cross-section parallel to the outer direction of the window element, the window element holder and the window element have outer contours that are essentially at the same height on the outside, particularly in the outer direction of the window element. In particular, the window element holder and the window element can have outer contours that are essentially aligned with each other on the outside in the cross-section.

[0022] It is advantageous if the high-pressure viewing cell in the sample receiving chamber has a holding device for, in particular, detachably securing, a microfluidic chip in the sample receiving chamber. The microfluidic chip, in particular a test fluid located in a microfluidic channel system of the microchip during use, can represent the sample. During use, a test fluid can expediently be supplied to a microfluidic channel system of the microfluidic chip via a fluid inlet of the microfluidic chip.The high-pressure viewing cell can have at least one supply line for supplying, during use, test fluid from outside the sample receiving chamber to a microfluidic chip arranged with the holding device via the supply line, via a fluid inlet of the microfluidic chip, and / or at least one discharge line for discharging, during use, test fluid from the microfluidic chip arranged with the holding device via the discharge line, via a fluid outlet of the microfluidic chip to outside the sample receiving chamber. The supply line and / or the discharge line can extend at least partially through the sample receiving chamber. The fluid inlet and / or fluid outlet of the microfluidic chip are typically fluidically connected to the microfluidic channel system of the microfluidic chip.The holding device can have one or more fluid connections via which the supply line and / or discharge line can be fluidically connected to the microfluidic chip, in particular to its fluid inlet or fluid outlet, when the microfluidic chip is arranged with the holding device. The supply line and / or discharge line can each be fluidically connected to a connection leadthrough of the high-pressure viewing cell, in particular connected to this, in order to pass examination fluid through the sample receiving chamber wall via the connection leadthrough. The connection leadthrough can be part of the supply line or discharge line. The supply line and / or discharge line usually form

[0023] A discharge line comprises a fluid receiving volume into which, during use, examination fluid can be conducted, which fluid receiving volume is separated from the sample receiving space, in particular a receiving cavity of the sample receiving space. During use, the fluid receiving volumes can be filled with an examination medium that is separate from the filling medium, in particular the filling fluid, with which the sample receiving space, in particular its receiving cavity, is filled.

[0024] The fluid inlet or fluid outlet of the microfluidic chip is usually fluidically connected to the microfluidic channel system of the microfluidic chip. The microfluidic channel system is usually formed with several fluidically connected fluid channels. In this way, rock porosity or a rock channel system, through which a fluid can be guided, can be simulated with the microfluidic chip or the microfluidic channel system. The microfluidic channel system usually has a volume for accommodating fluid of between 5 pl and 100 pl. The diameter of the fluid channels is usually less than 1000 pm, in particular less than 500 pm, in particular less than 50 pm. The microfluidic chip is usually plate-shaped. The microfluidic chip usually has a length and a width of less than 10 cm each.The height of the microfluidic chip is typically orthogonal to the length and width of the microfluidic chip, with the height generally being smaller than the length and width of the microfluidic chip. Typically, the microfluidic chip has two light-transmitting or transparent cover surfaces, usually formed with or from quartz glass, between which the microfluidic channel structure is formed. The cover surfaces are typically oriented parallel to a longitudinal and lateral extension of the microfluidic chip. The microfluidic chip can be part of the high-pressure viewing cell. The cover surfaces are typically located opposite each other on the microfluidic chip.It has proven useful if the holding device is designed to arrange the microfluidic chip in the sample receiving chamber in such a way that the microfluidic chip can be subjected to a filling medium pressure of a filling medium, in particular filling fluid, with which the sample receiving chamber can be filled, from a top and a bottom of the microfluidic chip. Typically, when the sample receiving chamber is filled with the filling medium, the filling medium borders the cover surfaces of the microfluidic chip. The holding device can have a chip carrier which is designed to arrange or fix a microfluidic chip, in particular detachably, on the holding device. As a rule, the high-pressure viewing cell has an inlet line for supplying a filling fluid or the filling medium into the sample receiving chamber and / or an outlet line for discharging the filling fluid or the filling medium from the sample receiving chamber.The sample receiving chamber typically defines a receiving cavity that can be filled with the filling fluid. The inlet line and / or the outlet line can each be fluidically connected to a connection passage of the high-pressure viewing cell, which is passed through a sample receiving chamber wall of the sample receiving chamber, in particular connected to said connection passage, in order to conduct filling fluid through the sample receiving chamber wall via the connection passage. The filling fluid can be the filling fluid.

[0025] It is advantageous if the high-pressure viewing cell has a temperature control device in order to, when used with the temperature control device, temperature control, in particular to heat and / or cool, fluid that is supplied to the sample receiving chamber or is supplied to it. The fluid can be the filling fluid and / or the test fluid. The temperature control device can be formed with one or more heating devices and / or cooling devices. The temperature control device can, for example, be implemented with an electrical resistance heater, one or more Peltier elements and / or a temperature control channel through which a temperature control medium flows. The high-pressure viewing cell can expediently have one or more temperature sensors in order to control the temperature control device depending on a measurement result of the temperature sensors. This can be implemented with an electronic control device of the high-pressure viewing cell.The temperature sensor, in particular an electrical connection cable and / or a temperature measuring head of the temperature sensor, can be introduced into the sample receiving chamber, in particular a region close to the holding device, via a measuring feedthrough channel passed through a sample receiving chamber wall. The measuring feedthrough channel can have a fluid receiving volume spatially separated from the sample receiving chamber, in particular the receiving cavity, in which the temperature sensor, in particular its electrical connection cable and / or the temperature measuring head are located. It is advantageous if the temperature control device is designed to temperature-control, in particular to heat and / or cool, connection feedthroughs passed through the sample receiving chamber wall for conducting fluid, in particular filling fluid and / or test fluid, through the sample receiving chamber wall in order to temperature-control the fluid.The temperature control device can have a heat transfer surface that contacts a sample receiving chamber wall, in particular on the outside, in a heat-transferring manner in order to temperature-control the respective fluid through the sample receiving chamber wall. The heat transfer surface can extend circumferentially around the sample receiving chamber, contacting the sample receiving chamber wall in a heat-transferring manner. The heat transfer surface can be formed by a temperature control band, in particular a heating band and / or cooling band.

[0026] In use, a sample arranged in the sample receiving chamber, in particular a microfluidic chip held by the holding device, can be observed with an optical measuring device, in particular a microscope, arranged in front of the window element or outside the sample receiving chamber, against the outward direction of the window element. The optical measuring device, in particular the microscope, can be part of the high-pressure viewing cell.

[0027] The window element can be formed with, in particular substantially from, glass. It is preferred if the window element is formed with, in particular from, sapphire, in particular sapphire glass. The window element holder is usually formed with, in particular substantially from, metal, in particular an iron alloy, preferably steel. The sample receiving space, in particular its receiving cavity, can have a freely selectable size depending on the intended application. It is particularly advantageous, in particular with regard to the examination of a microfluidic chip or of examination fluid in its microfluidic channel system, if the sample receiving space, in particular its receiving cavity, has a volume between 5 ml and 1000 ml, in particular between 10 ml and 500 ml, preferably between 15 ml and 100 ml, particularly preferably between 20 ml and 50 ml.It has proven useful to arrange a microfluidic chip in the holding device such that the average distance between the microfluidic chip and the inner transparent surface of the window element is less than 2 cm. Typically, the distance is between 0.1 mm and 10 mm, preferably between 0.2 mm and 0.7 mm. The distance can refer to an outer surface of the microfluidic chip facing the window element, in particular the cover surface. The distance typically refers to the window element through which an optical observation or measurement of the sample or microfluidic chip takes place.

[0028] For high usability, it is advantageous if the high-pressure viewing cell has a plurality of window element arrangements, in particular a first window element arrangement and a second window element arrangement, wherein the respective window element arrangement comprises a window element holder and a window element held by the window element holder, wherein the window element arrangements, in particular the window elements, are arranged on different, in particular opposite, sides of the sample receiving chamber. In particular, in this way, during use, a sample located in the sample receiving chamber can be illuminated through one of the window elements with light from an illumination device and observed through the other window element with an optical measuring device, in particular with a microscope.The window element holder and the window element of the respective window element arrangement can be implemented as described in this document. The respective window element holder and the respective window element can be referred to as the first or second window element and as the first or second window element holder, analogous to the designation of the respective first or second window element arrangement. The optical measuring device and / or the illumination device can be part of the high-pressure viewing cell. In particular, the optical measuring device, in particular the microscope, can be arranged in front of the first window element, opposite the outward direction of the first window element, in order to observe, in particular optically examine, the sample with the optical measuring device through the first window element.The illumination device can be arranged in front of the second window element, facing away from the outward direction of the second window element, in order to irradiate the sample with light through the second window element using the illumination arrangement. The holding device can be configured, during use, to arrange the microfluidic chip in the sample receiving space such that one of the cover surfaces of the microfluidic chip faces the first window element and the other cover surface of the microfluidic chip faces the second window element.

[0029] In the context of what is described in this document, the inside or inner side of a component of the high-pressure viewing cell usually refers to a side of the component facing the sample receiving space. In the context of what is described in this document, the outside or outer side of a component of the high-pressure viewing cell usually refers to a side of the component facing away from the sample receiving space, in particular opposite the sample receiving space on the component. Use, in particular of the high-pressure viewing cell, usually refers to a state of the high-pressure cell in which the sample receiving space, in particular a filling fluid volume of the sample receiving space, is filled with filling fluid, and a sample located in the sample receiving space is observed through the window element.Stop for a component in a specific direction of the component usually refers to a stop for movement of the component in that direction.

[0030] Further features, advantages, and effects of the invention will become apparent from the following description of an exemplary embodiment. The drawings, to which reference is made, show:

[0031] Fig. 1 shows a schematic representation of a high-pressure viewing cell for optically observing a microfluidic chip, in particular a flow of an examination fluid in a microfluidic channel system of the microfluidic chip; Figs. 2 and 3 show schematic representations of cross sections through the high-pressure viewing cell of Fig. 1;

[0032] Fig. 4 is a schematic representation of a window element of the high-pressure viewing cell of Fig. 1 held by a window element holder in a cross section through the high-pressure viewing cell.

[0033] Fig. 1 schematically shows a high-pressure viewing cell 1 for optically observing a microfluidic chip 2, in particular a flow of a test fluid in a microfluidic channel system of the microfluidic chip 2. The high-pressure viewing cell 1 has a sample receiving chamber 3 for receiving the microfluidic chip 2, wherein the microfluidic chip 2 is usually arranged, in particular held, in the sample receiving chamber 3 by a holding device 4 of the microfluidic chip 2. The high-pressure viewing cell 1 has at least one window element 5 in order to observe, in particular optically measure, the microfluidic chip 2 or its microfluidic channel system from outside the sample receiving chamber 3 through the window element 5. The window element 5 generally forms part of a sample receiving chamber wall of the sample receiving chamber 3. It is advantageous if the high-pressure viewing cell 1 has two window elements 5 located opposite one another with respect to the sample receiving chamber 3.The high-pressure viewing cell 1 is designed such that, during use, the sample receiving chamber 3 is filled with a filling fluid, for example water, at a high filling fluid pressure. Typically, during use, an outer surface of the microfluidic chip 2 is in direct contact with the filling fluid, so that the outer surface is subjected to the filling fluid pressure. Fig. 2 and Fig. 3 show schematic representations of cross sections through the high-pressure viewing cell 1 of Fig. 1, wherein fluid lines, in particular examination fluid lines 6 for supplying and / or removing examination fluid to or from the microfluidic channel system of the microfluidic chip 2, are not shown in Fig. 3 for easier recognizability of the structure.The high-pressure viewing cell 1 typically has a filling fluid line 24, in particular a filling fluid inlet line and / or a filling fluid outlet line, in order to supply filling fluid to the sample receiving chamber 3, in particular to a receiving cavity of the sample chamber, via the filling fluid line 24 from outside the sample receiving chamber 3, in particular via the filling fluid inlet line from outside the sample receiving chamber 3 or to discharge it via the filling fluid outlet line from there to outside the sample receiving chamber 3. The high-pressure viewing cell 1 typically has examination fluid lines 6, in particular in the form of a supply line and / or a discharge line, in order to supply an examination fluid to a microfluidic channel system of a microfluidic chip 2 arranged with the holding device 4 in the sample receiving chamber 3 via an inlet of the microfluidic chip 2, or to discharge it from outside the sample receiving chamber 3 via the examination fluid lines 6, in use.via an outlet of the microfluidic chip 2 from the microfluidic channel system to the outside of the sample receiving chamber 3. The test fluid can be, for example, an oil. Typically, during use, the filling fluid pressure and / or the test fluid pressure of the test fluid is greater than 100 bar. The high-pressure viewing cell can have a temperature control device 25 designed as a heating band, wherein the heating band contacts a sample receiving chamber wall on the outside in a heat-transferring manner in order to heat the respective fluid passed through the sample receiving chamber wall with the heating band during use.The window element 5 is held by a window element holder 7, wherein the window element 5 is tapered at least in sections in an outward direction A of the window element 5 from an internal pressure side of the window element 5 to an external pressure side of the window element 5, such that a positive connection is formed between a support element 8 of the window element holder 7 and the window element 5. Fig. 4 shows a schematic representation of a window element 5 of the high-pressure viewing cell 1 of Fig. 1, held by the window element holder 7, in a cross-section parallel to the outward direction A of the window element 5. In the cross-section through the window element 5 parallel to the outward direction A of the window element 5, the window element 5 has, at least in sections, a tapered side contour representing the side surface 9 in the outward direction A of the window element 5.The support element 8 has a through-channel 10 with a through-channel wall 11 designed to correspond in shape to the window element 5, wherein the window element 5 is inserted at least partially, preferably substantially entirely, into the through-channel 10 in the outward direction A, so that a positive connection is formed between the through-channel wall 11 and a side surface 9 of the window element 5. The through-channel wall 11 usually forms a stop for the side surface 9 in the outward direction A of the window element 5. Preferably, the window element 5 is designed to be conical at least in sections, in particular predominantly, preferably substantially, wherein the side surface 9 is formed with a conical outer surface of the conical shape of the window element 5.The window element 5 usually has an outer see-through surface 12 and an inner see-through surface 13, between which see-through surfaces 12, 13 the side surface 9 extends, usually circumferentially around the window element 5.

[0034] The window element 5 is typically inserted into the through-channel 10 such that the window element 5, in particular the side surface 9 of the window element 5, is pressed against the through-channel wall 11. In this way, a fluid-tight connection can be formed between the window element holder 7 and the window element 5. The through-channel wall 11 can expediently have a pressing surface formed with a sealing material, wherein the side surface 9 is pressed against the pressing surface. Preferably, the pressing surface is formed with a sealing element 14, in particular a sealing ring, wherein the sealing element 14 is typically arranged such that it extends circumferentially along the side surface 9 around the window element 5. This applies in particular when viewed from the opposite direction A of the window element 5 toward the window element 5.In this way, a fluid-tight press connection can be formed circumferentially around the window element 5 between the through-channel wall 11 and the side surface 9 of the window element 5. Preferably, the sealing element 14 is at least partially inserted in a form-fitting manner into a sealing element recess 15 of the through-channel wall 11, which recess is configured to correspond to the sealing element 14.

[0035] The window element holder 7 has an actuating device 16 in the form of a closure element 17 movable relative to the support element 8, with which a pressing force is exerted on the window element 5, so that the window element 5, in particular the side surface 9 of the window element 5, is pressed against the through-channel wall 11, in particular the pressing surface. The closure element 17 typically forms a stop for the window element 5 counter to the outward direction A of the window element 5. It is advantageous if the closure element 17 is a threaded ring reversibly screwed into the through-channel 10, so that the window element 5 is releasably enclosed in the through-channel 10 with the threaded ring. The threaded ring typically closes the through-channel 10 for the window element 5 on a side of the window element 5 facing the sample receiving chamber 3.The threaded ring is typically screwed into the through-channel 10 in such a way that the threaded ring presses the window element 5 against the through-channel wall 11, in particular the pressing surface. Typically, the threaded ring applies a pressing force to a surface of the window element 5 facing the sample receiving chamber 3. Preferably, the threaded ring is substantially completely recessed into the through-channel 10. The threaded ring is typically detachably connected to the support element 8 and can be detached from the support element 8, in particular by unscrewing it from the through-channel 10.

[0036] For the detachable connection of the window element holder 7 to a base structure of the high-pressure viewing cell 1, the window element holder 7 is pressed against the base structure with a fastening element 18, forming a positive connection with the fastening element 18. The fastening element 18 can be connected to the base structure with a screw connection. The fastening element 18 is preferably a fastening sleeve into which the window element holder 7 is at least partially inserted, in particular with a positive fit. By detaching the fastening element 18 from the base structure of the high-pressure viewing cell 1, the window element holder 7 can be detached from the base structure without detaching the connection between the window element holder 7 and the window element 5.The window element holder 7 can expediently have a stepped edge region with a step surface 19 on the outside, wherein the fastening element 18 has a projection 20, in particular designed to correspond in shape to the edge region, which projection 20 engages the step surface 19 in the outward direction A, forming a stop for the step surface 19. Typically, the window element holder 7 has a contact surface 21 which is pressed against a counter surface 22 of the basic structure. The contact surface 21 and / or the counter surface 22 can be formed with a sealing element 14, in particular a sealing ring, in order to implement a fluid-tight connection between the contact surface 21 and the counter surface 22. The sealing element 14 can be inserted in a form-fitting manner, at least partially, into a recess in the contact surface 21 and / or the counter surface 22, said recess being designed to correspond in shape to the sealing element 14.The sealing element 14 can extend circumferentially around the window element 5 when viewed opposite to the outward direction A of the window element 5.

[0037] The high-pressure viewing cell 1 can have a plurality of window element arrangements 23, each formed with a window element holder 7 and a window element 5 held by the latter, in particular on different sides of the sample receiving chamber 3. The window element holder 7 and the window element 5 of the respective window element arrangement 23 can be implemented as described, in particular above, in this document. It is particularly advantageous if window element arrangements 23, in particular their window elements 5, are arranged on opposite sides of the sample receiving chamber 3. As a result, during use, the microfluidic chip 2 or a flow of the examination fluid in the microfluidic channel system of the microfluidic chip 2 can be irradiated with light through one of the window elements 5 and observed with a microscope through the other window element 5 opposite this window element on the sample receiving chamber 3.

Claims

Patent claims 1. High-pressure viewing cell (1) for the optical observation of a sample, in particular a microfluidic chip (2), wherein the sample can be arranged in a sample receiving space (3) of the high-pressure viewing cell (1), wherein the high-pressure viewing cell (1) has a window element (5) for observing the sample through the window element (5) and a window element holder (7) for holding the window element (5), characterized in that in order to produce a connection, in particular a form-fitting and / or force-fitting connection, between the window element holder (7) and the window element (5), the window element (5) is tapered at least in sections from an internal pressure side of the window element (5) to an external pressure side of the window element (5).

2. High-pressure viewing cell (1) according to claim 1, characterized in that the window element holder (7) positively delimits the window element (5) on a side surface (9) of the window element (5), which side surface (9) runs between an inside transparent surface (13) facing the sample receiving space (3) and an outside transparent surface (12) of the window element (5) located outside the sample receiving space.

3. High-pressure viewing cell (1) according to claim 2, characterized in that the side surface (9) is designed at least in sections as a rotational surface, in particular a conical surface, tapering in the outward direction (A) of the window element (5).

4. High-pressure viewing cell (1) according to claim 2 or 3, characterized in that the window element holder (7) forms a through-channel (10) into which the window element (5) is at least partially inserted, so that the side surface (9) is pressed against a through-channel wall (11) forming the through-channel (10).

5. High-pressure viewing cell (1) according to one of claims 2 to 4, characterized in that the window element holder (7) has a pressing surface, in particular formed with an elastically and / or plastically deformable sealing element (14), wherein the side surface (9) is pressed against the pressing surface in order to implement a fluid-tight press connection.

6. High-pressure viewing cell (1) according to one of claims 1 to 5, characterized in that the window element holder (7) has an actuating device (16) in order to press the window element (5) against the window element holder (7) and / or to change a pressing force between the window element (5) and the window element holder (7) upon actuation of the actuating device (16).

7. High-pressure viewing cell (1) according to claim 6, characterized in that the actuating device (16) forms a movable stop for a surface of the window element (5) facing a sample receiving space (3) of the high-pressure viewing cell (1).

8. High-pressure viewing cell (1) according to one of claims 1 to 7, characterized in that the window element holder (7) is detachably connected to a basic structure of the high-pressure viewing cell (1), wherein the window element holder (7) is detachable from the basic structure without releasing the connection between the window element holder (7) and the window element (5).

9. High-pressure viewing cell (1) according to one of claims 1 to 8, characterized in that the window element holder (7) is detachably connected to a basic structure of the high-pressure viewing cell (1), wherein the window element holder (7) is pressed against a counter surface (22) of the basic structure by a fastening element (18) circumferentially surrounding the window element holder (7), wherein in particular a pressing force exerted by the fastening element (18) on the window element holder (7) can be changed by screwing in the fastening element (18).

10. High-pressure viewing cell (1) according to one of claims 1 to 9, characterized in that the high-pressure viewing cell (1) in the sample receiving space (3) has a holding device (4) for the, in particular detachable, arrangement of a microfluidic chip (2) in order to supply an examination fluid to a microfluidic channel system of the microfluidic chip (2) via a fluid inlet of the microfluidic chip (2).

11. High-pressure viewing cell (1) according to claim 10, characterized in that the holding device (4) is designed to arrange the microfluidic chip (2) in the sample receiving space (3) in such a way that the microfluidic chip (2) can be subjected to a filling medium pressure of a filling medium with which the sample receiving space (3) can be filled from a top side and a bottom side of the microfluidic chip (2).

12. High-pressure viewing cell according to one of claims 1 to 11, characterized in that the high-pressure viewing cell (1) has at least one supply line in order to supply, in use, via the supply line, a microfluidic chip (2) arranged with the holding device (4) from outside the sample receiving space (3) with examination fluid via a fluid inlet of the microfluidic chip, and / or has at least one discharge line in order to discharge, in use, via the discharge line, examination fluid from the microfluidic chip (2) arranged with the holding device (4) to outside the sample receiving space (3) via a fluid outlet of the microfluidic chip.

13. High-pressure viewing cell (1) according to one of claims 1 to 12, characterized in that the high-pressure viewing cell (1) has an inlet line for supplying a filling fluid into the sample receiving space (3) and / or an outlet line for removing filling fluid from the sample receiving space (3).

14. High-pressure viewing cell (1) according to one of claims 1 to 13, characterized in that the high-pressure viewing cell (1) has a temperature control device in order to temperature control, in particular to heat and / or cool, fluid which is supplied to the sample receiving space (3) or is supplied thereto when used with the temperature control device.

15. High-pressure viewing cell (1) according to one of claims 1 to 14, characterized in that the high-pressure viewing cell (1) has a plurality of window element arrangements (23), wherein the respective window element arrangement (23) comprises a window element holder (7) and a window element (5) held by the window element holder (7), wherein the window element arrangements (23) are arranged on different, in particular mutually opposite, sides of the sample receiving space (3).

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