DE102022134986A1 - Layered fluid filter and filter element with fluid inlet and fluid outlet on the same side - Google Patents

Abstract

Fluid filter (100) for filtering a fluid, in particular in an analysis device (10), the fluid filter (100) having a layered structure (102) which has at least one microfluidic structure (104) for supplying and removing the fluid, and a filter element (106 ) which is designed to filter the fluid supplied by means of the at least one microfluidic structure (104) and which is arranged on and/or in the layered structure (102), with a fluid supply (108) for supplying the fluid to be filtered and a fluid discharge (110) for discharging the filtered fluid are arranged on the same side of the layered structure (102) and are fluidically coupled to the at least one microfluidic structure (104).

Description

TECHNICAL BACKGROUND

The present invention relates to a fluid filter, an analysis device and a method for manufacturing a fluid filter.

In an HPLC, a liquid (mobile phase) is typically measured at a very precisely controlled flow rate (e.g. in the range of microliters to milliliters per minute) and at a high pressure (typically 20 to 1000 bar and beyond, currently up to 2000 bar). , in which the compressibility of the liquid is noticeable, is moved through a so-called stationary phase (e.g. in a chromatographic column) in order to separate individual components of a sample liquid introduced into the mobile phase. Such an HPLC system is, for example, from EP 0,309,596 B1 of the same assignee, Agilent Technologies, Inc. known. Such an HPLC system often has one or more switchable fluid valves.

Fluid filters are used in analyzers such as HPLC to filter out particles from fluids. The assembly of fluid filters on an analysis device, in particular between two capillaries, is conventionally complex and error-prone.

EPIPHANY

It is an object of the invention to provide a fluid filter that can be assembled in a simple manner and is robust against errors. The object is solved by means of the independent claims. Further embodiments are shown in the dependent claims.

According to an exemplary embodiment of the present invention, a fluid filter for filtering a fluid (in particular in an analysis device) is created, the fluid filter having a layered structure which has at least one microfluidic structure (preferably a plurality of microfluidic structures) for supplying and removing the fluid, and has a filter element which is designed to filter the fluid supplied by means of the at least one microfluidic structure and which is arranged on and/or in the layered structure, with a fluid supply for supplying the fluid to be filtered and a fluid discharge for discharging the filtered fluid on the same side of the layer structure are arranged and are fluidically coupled to the at least one microfluidic structure.

According to another exemplary embodiment, an analysis device for analyzing a fluidic sample is provided, the analysis device having at least one fluid filter with the features described above.

According to a further exemplary embodiment, a method for producing a fluid filter for filtering a fluid (in particular in an analysis device) is provided, the method including providing a layered structure with at least one microfluidic structure for supplying and removing the fluid, arranging a filter element, which for filtering of the fluid supplied by means of the at least one microfluidic structure is formed on and/or in the layered structure, and arranging a fluid supply for supplying the fluid to be filtered and a fluid discharge for discharging the filtered fluid on the same side of the layered structure, the fluid supply having and the fluid discharge are fluidically coupled to the at least one microfluidic structure.

In the context of the present application, the term “fluid filter” means in particular a fluid component that retains solids from a gas and/or liquid flow. A fluid that has solid particles can therefore be subjected to a filtration in a fluid filter, which can be effected, for example, by pressing or drawing the fluid through the fluid filter.

In the context of the present application, the term “fluid” means in particular a liquid and/or a gas, optionally having solid particles.

In the context of the present application, the term “analysis device” can refer in particular to a device that is able and configured to examine a fluidic sample, in particular to separate it, and further in particular to separate it into different fractions. For example, such a sample separation can take place by means of chromatography or electrophoresis. Preferably, the analysis device can be a liquid chromatography sample separation device.

In the context of the present application, the term “layer structure” can be understood in particular to mean a body or a set of bodies which has a plurality of layers which are arranged in particular parallel to one another and are preferably connected to one another and are preferably planar and which form a common, preferably one-piece component can. Alternatively, however, the layers can also remain completely or partially separate from one another. The layer structure may have or consist of layered structures. A layer structure can have metallic and/or non-metallic (for example ceramic) layer structures.

In the context of the present application, the term “layer structure” can be understood in particular as meaning a planar and flat, preferably metallic, structure that can be processed to form at least one microfluidic structure. A layered structure can include or consist of a metal (in particular an elemental metal). For example, a layered structure may be formed from a stainless, corrosion-resistant steel alloy. A layer structure can be a continuous layer (preferably made of metal) or can be a structured layer with one or more recesses extending horizontally and/or vertically and/or obliquely. A layered structure can also be formed from a plurality of coplanarly arranged islands that are not connected to one another (preferably metallic).

In the context of the present application, the term "microfluidic structure" is understood in particular to mean a branched or unbranched channel, a plurality of such channels or another fluidic structure (e.g. a groove or a cavity) with dimensions in the range from micrometers to millimeters a fluid can flow through. According to one embodiment, an inner diameter of the at least one microfluidic structure can be in a range between 0.05 mm and 1 mm, in particular in a range between 0.1 mm and 0.5 mm. The microfluidic structures can have cavities free of solid material or can be partially filled, for example with a stationary phase as sample separation material.

In the context of the present application, the term “filter element” is understood to mean, in particular, an element of a fluid filter on which the actual filtration process of the fluid takes place. For example, such a filter element can be a sintered body, a porous body, a stacked lattice or sieve structure or a granulate, which has gaps through which fluidic components can flow, whereas solid particles can be retained on the filter element. The filter element can preferably be designed as a filter disk. For example, such a filter disk can have a diameter in a range from 1 mm to 13 mm, for example 2 mm.

In the context of the present application, the term "supply and discharge of fluid on the same side of the layer structure" is understood in particular as a structural feature of a fluid filter, according to which two fluid interfaces are defined for introducing fluid to be filtered into the fluid filter and for discharging filtered fluid from the fluid filter are arranged on a common side of the layer structure or the fluid filter. In contrast to conventional fluid filters, which are fluidically coupled to a supply capillary on one side and a discharge capillary on an opposite other side, in a fluid filter according to an exemplary embodiment of the invention, fluid can be supplied and discharged by forming a single common connection of the fluid filter with an analyzer or other fluid processing device or fluid component. For example, the supply and discharge of fluid can be arranged on a common end face of the fluid filter.

In the context of the present application, the term “fluidic sample” is understood to mean in particular a medium, more particularly a liquid, which contains the material to be analyzed (e.g. a biological sample), such as a protein solution, a pharmaceutical sample, etc

According to an exemplary embodiment of the invention, a fluid filter for filtering a fluid (in particular a mobile phase in an analysis device such as an HPLC) is created, which has a layered structure with one or more microfluidic structures fluidically coupled to one another. The latter are used for supplying fluid to be filtered and for removing filtered fluid. In addition, the fluid filter has a filter element which filters the fluid and for this purpose is designed to be fluidically coupled or capable of being coupled to microfluidic structures of the layered structure. Both a fluid supply for supplying the fluid to be filtered and a fluid discharge for discharging the filtered fluid are advantageously positioned on a common side of the layered structure and are fluidically coupled to said microfluidic structure. The provision of planar and stacked layer structures leads to a particularly compact configuration of the fluid filter and nevertheless allows a freely selectable formation of microfluidic structures for well-defined fluid management. A filter element mounted on or in the layer structure can perform the actual filter function and—for example alone or in combination with the layer structures—can be provided as a replaceable wearing part. The configuration of the fluid supply and the fluid discharge on the same side of the layer structure is particularly advantageous. A corresponding design is achieved by providing a layered structure with a microfluidic structure integrated therein Ren favors and allows a particularly easy handling by a user. This is because the formation of a single common fluid interface is sufficient, whereas the complicated handling of two capillaries independently of one another can be dispensed with.

Additional configurations of the fluid filter, the analysis device and the method are described below.

According to one exemplary embodiment, the layer structure can be formed from a plurality of layer structures connected to one another. A stack of layers can thus be formed, the individual layer structures of which can have microfluidic structures that correspond to one another and can be individually and easily formed, in order to bring about a more complex fluid line system in a very small space. In this case, the layer structures can be connected to one another integrally, for example by forming a diffusion-bonded or diffusion-welded layer structure. Such a configuration is particularly user-friendly, since a user only needs to handle a single component (for example when replacing the layer structure, possibly including the filter element). Alternatively, however, it is also possible for the layer structures of the layered structure to rest loosely on one another in whole or in part. For example, the individual layer structures can then be easily accommodated in an accommodating space of a housing body.

According to one embodiment, the layer structure can be formed from a plurality of metal layer structures. It is particularly advantageous to form the individual layer structures from metallic layers. Individual metal layers can be easily processed in order to form microfluidic structures of any configuration therein. In addition, an interconnected layered component can be formed from individual metal layers in a simple manner. In particular, the layer structure can advantageously be embodied as a metallic microfluidic (Metal MicroFluidic, MMF) arrangement, for example as a diffusion bond component or metal laminate.

According to one embodiment, a microfluidic structure of the layered construction can form at least one flat, widened fluid exchange surface directly adjacent to the filter element, in particular on the fluid inlet side (i.e. where fluid to be filtered is fed to the filter element) and/or on the fluid outlet side (i.e. where filtered fluid is discharged from the filter element). For example, a fluid can be supplied to the filter element by first being guided through capillary-like through-holes in individual layer structures before the fluid is then expanded flatly at an exchange surface immediately in front of the filter element. This can be realized, for example, by forming a microfluidic structure in a layered structure in the form of a planar cavity or preferably as a planar groove structure (i.e. in a manner as described in the following paragraph). As a result, the fluid can first be fed to the filter element with a small dead volume and only there can it be widened over its surface area, so that the fluid can preferably flow through the full surface of the filter element. This prevents the filter element from clogging quickly and keeps the fluid resistance low when it flows through the fluid valve.

In particular, the two-dimensionally widened exchange surface can be designed as a two-dimensional groove structure with webs arranged in between. For example, a spiral, a meander and/or a zigzag can form a two-dimensional or two-dimensional exchange surface between a layered structure of the layered structure and the filter element. In this case, the exchange surface can correspond to a main surface of the filter element. Advantageously, webs between mutually adjoining groove sections of the areally widened exchange surface can improve the mechanical stability of the filter element and thus contribute to high-pressure stability.

According to one embodiment, the at least one microfluidic structure can have at least one through hole through at least one layer structure of the layered structure and/or at least one groove, in particular at least one spiral, meandering or elongated groove, in a main surface of at least one layered structure of the layered structure. Such a groove, which distributes the fluid to be filtered two-dimensionally onto the filter element, can bring about a precise fluid distribution in a precisely defined manner.

According to one embodiment, the filter element may include a sintered body or a mesh stack. A sintered body can, for example, be formed from initially unconnected metal particles or ceramic particles which are connected to one another by means of sintering (i.e. by increasing the temperature and preferably increasing the pressure) to form an integral body. Small interstices remain between the integrally bonded particles, which may be traversable for fluid but impassable for solid particles. Alternatively, the filter element can also be formed by several meshes (for example metal meshes) placed one on top of the other, each with small through-holes, which in combination form intermediate spaces which are impermeable to solid particles and permeable to gases or liquids.

According to one exemplary embodiment, the filter element can be embedded in the layered structure over its entirety. According to such a configuration, the filter element can be surrounded by one or more layer structures of the layered construction along its entire lateral circumference and can therefore be held in position. A loss of position of the filter element due to slipping or the like can thereby be avoided in the lateral circumferential direction. However, it is alternatively or additionally possible for the filter element to be embedded between the layer structures in the axial direction or in the stacking direction of the layer structures. This also makes it impossible to change the position of the filter element in the axial direction. A user can also handle the filter element and layer structure in one piece, which further improves user comfort.

According to one exemplary embodiment, the fluid filter can have a housing body in which the layer structure and the filter element are arranged. The housing body can form a component which, on the one hand, accommodates the layer structure and filter element and, on the other hand, is handled by a user when assembling or disassembling the fluid filter. Such a housing body can be designed, for example, as a metal body or as a plastic body.

According to one exemplary embodiment, the housing body can have a thread, in particular an external thread, for screwing to a fluid component to be fluidically coupled to the fluid filter. Furthermore, the housing body can have a drive for rotating the fluid filter. Clearly, the housing body can be a hollow screw, in which the fluid filter and the layer structure can be accommodated. The thread may preferably be an external thread which can be screwed into an internal thread of an analyzer (or vice versa) in order to mechanically connect the fluid valve to the analyzer and at the same time form a fluid connection. The drive can be formed as a non-rotationally symmetrical recess in an end face of the housing body. For example, the drive can be a hex socket, an internal or external hexalobular drive, a cross drive or a slotted drive. The housing body can be screwed into the analysis device or unscrewed from the analysis device by means of the drive, for example by means of a screwdriver or a motor-driven screwing tool (for example a cordless screwdriver). In particular, by simply screwing the fluid filter to an analysis device or the like, a fluid-tight connection can be formed between them, in particular a high-pressure-tight connection (preferably at least up to 1000 bar, particularly preferably up to at least 2000 bar).

According to one exemplary embodiment, the layered structure together with the filter element can be inserted into the housing body in an exchangeable manner as a one-piece component that can be handled. A user then only needs to handle two components to assemble or disassemble the fluid filter, namely the component made up of the layer structure and filter element on the one hand and the housing body on the other. As a wearing part, the component consisting of the layer structure and the filter element can be removed separately from the housing body and replaced by a replacement component consisting of a new layer structure and a new filter element. The case body can be reused, favoring more efficient use of resources.

According to an exemplary embodiment, a connection layer structure of the layer structure can have the fluid supply and the fluid discharge. The connection layer structure can represent the only layer structure of the layer structure that is externally accessible in the installed state, on which microfluidic structures for supplying fluid for filtering and for removing fluid after filtering can be formed so that it is externally accessible. Said microfluidic structures can have through-holes which are fluidically separated from one another.

According to one exemplary embodiment, the connection layer structure can be designed such that the fluid supply and the fluid discharge are aligned such that they can be fluidically coupled to corresponding fluid connections of a fluid component to be fluidly coupled to the fluid filter, regardless of a rotational position of the fluid filter. This enables the fluid filter to be handled by a user in a manner that is particularly robust against errors. Particularly when the fluid filter is mounted on an analysis device by screwing in a housing body, forming a fluid connection on the supply side and discharge side is advantageous regardless of an angular position of the fluid filter relative to the analysis device.

According to one exemplary embodiment, the connection layer structure as a microfluidic structure can have a, in particular central, through-hole and an annular groove fluidically coupled to at least one further through-hole, in particular to two further through-holes, in particular surrounding the central through-hole. The angle-independent formation of a supply-side and discharge-side fluid coupling between the fluid filter and the analysis device can be accomplished, for example, by at least one through-hole serving for fluid supply in the connection layer structure and/or at least one through-hole serving for fluid drainage in the connection layer structure can be fluidically coupled to an annular groove in the connection layer structure, which can form the actual fluid interface for connecting the fluid filter to the analysis device. Such an annular groove can preferably be designed to be rotationally symmetrical or circular in order to enable a fluid coupling between the connection layer structure and the analysis device independently of an angular position of a housing body after it has been screwed into an analysis device. A configuration is particularly preferred in which one of the fluid supply and fluid discharge is formed by means of a circular annular groove in combination with at least one through hole in the connection layer structure and the other of the fluid supply and fluid discharge is formed by means of a further central through hole in the connection layer structure.

According to one embodiment, an end layer structure of the layer structure can be designed to subject the fluid flowing in from the fluid supply, in particular before filtering by means of the filter element, to a flow direction reversal and, in particular through the filter element, to redirect it back in the direction of the fluid discharge. The end layered structure is a layered structure of the layered construction, which faces away from the fluid supply from and the fluid discharge to the analysis device. In other words, the end layer structure can form a layer structure of the layer structure that is opposite the connection layer structure and faces away from it in the axial direction. A flow reversal of the fluid can be forced at the end layer structure. While the fluid can flow in upstream of the end layer structure along a first direction, at least one microfluidic structure of the end layer structure can be configured such that the fluid can flow back downstream of the end layer structure along a second direction inverse to the first direction. In particular, the fluid can be supplied to the filter element immediately after the flow reversal and can thereby be subjected to filtering in the filter element.

According to one exemplary embodiment, the end layer structure can have a microfluidic structure for promoting a planar fluid exchange with the filter element, in particular by means of a microfluidic structure designed as a spiral groove in a main surface of the end layer structure. While the fluid can flow from the connection layer structure through the layer structure along a capillary-like flow path and thus at least predominantly one-dimensionally, the fluid can be expanded two-dimensionally immediately before it reaches the filter element in order to promote a uniform flow through the filter element. In this way, a low dead volume can be combined with efficient use of the filter element.

According to an exemplary embodiment, an intermediate layer structure of the layer structure can be designed to promote a fluid exchange between the filter element and the fluid discharge. The intermediate layer structure can be arranged inside the layer structure, in particular between the connection layer structure and the end layer structure. Said intermediate layer structure can spatially collect the filtered fluid, starting from the filter element, and lead it back towards the connection layer structure.

According to one exemplary embodiment, the intermediate layer structure can have a microfluidic structure for promoting a planar fluid exchange with the filter element, in particular by means of a microfluidic structure designed as a spiral groove in a main surface of the intermediate layer structure. Similar to that described above for the final layer structure upstream of the filter element, the intermediate layer structure downstream of the filter element can promote a two-dimensional liquid exchange between the filter element and the microfluidic structures. As a result, the filtered fluid is collected, in particular coupled into a two-dimensional groove and can then be fed back to the initial layer structure for a one-dimensional fluid return.

According to an exemplary embodiment, an accommodation layer structure of the layered construction can have an accommodation opening for the peripheral accommodation of the filter element. The receiving layer structure can have a central receiving opening into which the filter element can be fitted. In particular, the filter element (for example a filter pad) can be pressed into the receiving layer structure (in particular into its receiving space) so that it is held captive and in a laterally defined manner on the layer structure. Apart from its central through-hole for receiving the filter element, the receiving layer structure can have at least one further microfluidic structure through which fluid can be conducted radially past the filter element through the layer structure. In this way, fluid to be filtered can also be handled separately from filtered fluid in the receiving layer structure.

According to one embodiment, a lateral deflection layer structure of the layer structure can be a microfluidic structure for, in particular their rectilinear, redirecting a flow of the fluid in a lateral (e.g. radial) direction. Thus, in the lateral bypass layered structure, fluid can be subjected to intermittent lateral flow from an axial flow direction to direct the fluid around the filter element. This can be achieved in the lateral bypass layered structure, for example, by means of radial grooves.

According to one exemplary embodiment, the layer structure can be shaped to provide rotation protection. For example, an outer contour of the layered structure can be non-rotationally symmetrical in order to be able to insert the layered structure into a counter-body (for example a housing body or directly into an analysis device) only in a specific angular position. It is then possible to dispense with measures to bring the structure of the microfluidic structure in the layered structure into fluid coupling with the analysis device independently of a rotational position of the fluid filter.

According to one exemplary embodiment, the fluid filter can have at least one further filter element, which is designed to filter the fluid supplied by means of the at least one microfluidic structure and which is to be arranged on and/or in the layered structure. Thus, a plurality of filter elements can be arranged on the layered structure, one of which can be selectively brought into fluid communication with the microfluidic structure of the layered structure. As a result, the individual filter elements for filtering fluid can be positioned one after the other before a user has to exchange exhausted or loaded filter elements. This allows a replacement interval to be extended.

According to an exemplary embodiment, the filter element and the at least one further filter element can be attached so that they can be moved, in particular rotated, so that a respective one of the filter elements can be brought into position for filtering the supplied fluid. For example, the filter elements can be arranged in a turret component which can be rotated in order to sequentially bring the individual filter elements into operative connection with the microfluidic structure of the layered construction.

According to one exemplary embodiment, the fluid filter can be configured for pressure-tight operation up to at least 1000 bar, in particular up to at least 2000 bar. The described configuration of the fluid filter with layered construction and microfluidic structure as well as a fitted filter element is ideally suited for high-pressure applications. Therefore, the fluid filter can also be used advantageously in high-pressure analysis devices, such as an HPLC.

According to one embodiment, the fluid filter can be designed to filter a mobile phase. A mobile phase can be a solvent or solvent composition that can be used, for example, in an analyzer to aid in an analysis. For example, a mobile phase can be used during a gradient run of a liquid chromatography sample separator.

In general, fluid filters according to exemplary embodiments of the invention can advantageously be used wherever (for example in an analysis device) operational abrasion of solid particles can take place, which can be filtered out by means of such a fluid valve. However, other applications of exemplary embodiments of the invention other than analyzers are also possible. For example, a fluid filter according to an exemplary embodiment of the invention can also be used as a gasoline filter in an automobile or as a filter for food (for example apple juice or beer).

According to one embodiment, the fluid filter may be attached to an analytical pump of a sample separation device. For example, the fluid filter can be screwed onto a pump head. In an HPLC, undesirable particle generation can occur, for example, at an analytical pump in which a piston reciprocates at high speed in a piston chamber and can generate abrasion at even a small displacement. The attachment of a fluid filter can effectively remove solid particles from the mobile phase on such an analytical pump.

According to one embodiment, the fluid filter for filtering fluid may be mounted upstream of the sample separator. In this way, clogging of a sample separation device, in particular a chromatographic separation column, can be effectively avoided. The fluid filter can thus be used as a pre-filter for a sample separation device, which can be particularly sensitive to dirt, for example.

According to one embodiment, the fluid filter for filtering fluid can be attached in the area of a rotary fluid valve. Rotating shear valves, which are used in HPLC, for example as injection valves, can also generate abrasion that can be effectively filtered out by a fluid filter according to an exemplary embodiment of the invention.

According to one embodiment, the fluid filter for filtering fluid can be attached in the area of a sample needle. In an HPLC, a sample needle can be moved between a sample container and a seat while a sample is being taken, and abrasion can also be generated when a fluid-tight connection is formed between the sample needle and seat.

According to one embodiment, the method may include attaching the filter element to the layered structure and/or attaching metal layer structures of the layered structure to one another by means of diffusion bonding. Diffusion bonding or diffusion welding is a solid state joining technique that can be used to join layered structures formed as metal layered structures and can join like and dissimilar metals. Diffusion bonding is based on the principle of solid-state diffusion, in which the atoms of two solid, metallic surfaces bond together when subjected to increased pressure in conjunction with increased temperature (preferably below the melting temperature of the metals involved). Diffusion bonding can be used particularly advantageously when metallic layer structures are to be formed in the form of interconnected metallic thin-layer foils. Advantageously, when metallic layer structures are connected by means of diffusion bonding, microfluidic structures of the layer structures can be retained and even brought into permanent fluid connection with one another. As an alternative to diffusion bonding, it is also possible, for example, to glue layer structures of the layered structure together.

According to one embodiment, the metal layer structures may be formed of stainless steel. Corrosion-resistant steel has proven to be very suitable both as a material for joining to other metal layered structures and for forming fluidic structures therein. In addition, corrosion-resistant steel is sufficiently rust-free and inert to be able to carry even aggressive biological and chemical substances inside it.

According to one embodiment, an inner diameter of the at least one microfluidic structure can be in a range between 0.05 mm and 1 mm, in particular in a range between 0.1 mm and 0.5 mm. With such dimensions, narrowing or even complete blocking of the microfluidic structures can be avoided. At the same time, these small structure sizes are suitable for coping with the required low and at the same time highly precise flow rates and limited fluid volumes of modern sample separation devices. Microfluidic structures of these dimensions are particularly suitable for sample separation tasks, for example using chromatography.

According to one embodiment, the at least one microfluidic structure may include at least one of a group consisting of a fully-constrained microfluidic channel and a microfluidic groove. In this context, a groove is understood to mean, in particular, an elongate channel-shaped depression. A channel, in contrast to a groove, is a cavity which is defined around its entire circumference and which can have a circular or rectangular cross-section, for example. However, other microfluidic structures are also possible, for example pores. Such microfluidic structures can be formed in the layer structure in the horizontal direction and/or as a vertical fluidic connection structure.

According to an exemplary embodiment, the method can include connecting the plurality of metal layer structures by means of supplying heat and/or applying pressure. For example, the metal layer structures can first be structured (for example by means of a lithography and etching process, by means of a laser treatment and/or by means of mechanical drilling or milling) and can subsequently be connected to one another. As a result, the metal layer structures can enter into a non-destructive, inseparable connection without fluidic channels in their interior being undesirably closed by diffusion bonding.

According to one embodiment, the analysis device can be designed as a sample separation device and have an analytical pump for driving a mobile phase and the fluidic sample introduced into the mobile phase and a sample separation device for separating the fluidic sample introduced into the mobile phase. In this case, the mobile phase and/or the fluidic sample can be said fluid. Clearly, the analysis device can be designed as a chromatographic sample separation device, in particular for liquid chromatography or as an HPLC. In the context of the present application, the term “mobile phase” means in particular a fluid, further in particular a liquid, which can be used, for example, as a carrier medium for transporting the fluidic sample, in particular between a fluid drive and a sample separation device. However, mobile phase can also be used in a fluid delivery device to influence the fluidic sample. For example, the mobile phase may contain a (e.g. organic and/or inorganic) solvent or solvent composition (e.g. water and ethanol). In the context of the present application, the term “analytical pump” can be understood in particular as a device for conveying and moving fluid, which can optionally bring the fluid to an increased pressure. For example, such a fluid drive can be a pump, for example a single-stage or multi-stage piston pump. For example, the fluid drive can be designed as a high-pressure chromatographic pump. In the context of the present application, the term “sample separation device” can be understood in particular as a component that can separate a fluidic sample, in particular into fractions. For example, such a sample separation device can have a stationary phase on which the sample is adsorbed and is detached or desorbed fractionally from the stationary phase by varying a solvent composition (for example according to a gradient profile). For example, a sample separation device can be a chromatographic separation column.

The sample separation device can be a microfluidic measuring device, a life science device, a liquid chromatography device, a gas chromatography device, an HPLC (high performance liquid chromatography), a UHPLC system or an SFC (supercritical liquid chromatography) device. However, many other applications are possible.

According to one exemplary embodiment, the sample separation device can be designed as a chromatographic separation device, in particular as a chromatography separation column. In the case of a chromatographic separation, the chromatographic separation column can be provided with an adsorption medium. The fluidic sample can be stopped at this and only subsequently be detached again in fractions when a specific solvent composition is present, with which the separation of the sample into its fractions is accomplished.

A pumping system for conveying fluid can, for example, be set up to convey the fluid or the mobile phase through the system at a high pressure, for example a few 100 bar up to 1000 bar and more.

The sample separation device can have a sample injector for introducing the sample into the fluidic separation path. Such a sample injector can have an injection needle that can be coupled to a seat in a corresponding fluid path, with the needle being able to be moved out of this seat in order to take up a sample, with the sample being in a fluid path after reinserting the needle into the seat, which, for For example, by switching a valve, it can be switched into the separation path of the system, which leads to the introduction of the sample into the fluidic separation path. In another embodiment of the invention, a sample injector can be used with a needle that operates without a seat.

The sample separation device may include a fraction collector for collecting the separated components. Such a fraction collector can lead the different components of the separated sample into different liquid containers, for example. However, the analyzed sample can also be fed to an outflow container.

The sample separation device can preferably have a detector for detecting the separated components. Such a detector can generate a signal which can be observed and/or recorded and which is indicative of the presence and quantity of the sample components in the fluid flowing through the system.

character list

• 1 zeigt ein HPLC-System als Probentrenngerät mit mehreren Fluidfiltern gemäß einem exemplarischen Ausführungsbeispiel der Erfindung.
• 2 zeigt eine Explosionsdarstellung eines Fluidfilters gemäß einem exemplarischen Ausführungsbeispiel der Erfindung.
• 3 zeigt eine andere Explosionsdarstellung des Fluidfilters gemäß 2.
• 4 zeigt eine Querschnittsansicht des Fluidfilters gemäß 2 und 3 in einem montierten Zustand.
• 5 zeigt eine Explosionsdarstellung eines Fluidfilters gemäß einem anderen exemplarischen Ausführungsbeispiel der Erfindung.
• 6 zeigt eine Draufsicht eines Fluidfilters gemäß noch einem anderen exemplarischen Ausführungsbeispiel der Erfindung.
• 7 zeigt eine räumliche Ansicht eines Fluidfilters gemäß noch einem anderen exemplarischen Ausführungsbeispiel der Erfindung.

Other objects and many of the attendant advantages of embodiments of the present invention will be readily appreciated and become better understood by reference to the following more detailed description of embodiments taken in connection with the accompanying drawings. Features that are essentially or functionally the same or similar are provided with the same reference numbers.

• 1 shows an HPLC system as a sample separation device with multiple fluid filters according to an exemplary embodiment of the invention.
• 2 12 shows an exploded view of a fluid filter according to an exemplary embodiment of the invention.
• 3 FIG. 12 shows another exploded view of the fluid filter according to FIG 2 .
• 4 FIG. 12 shows a cross-sectional view of the fluid filter according to FIG 2 and 3 in an assembled condition.
• 5 12 shows an exploded view of a fluid filter according to another exemplary embodiment of the invention.
• 6 12 shows a plan view of a fluid filter according to yet another exemplary embodiment of the invention.
• 7 12 shows a perspective view of a fluid filter according to yet another exemplary embodiment of the invention.

The representation in the drawings is schematic.

Before exemplary embodiments are described with reference to the figures, some basic considerations should be summarized, on the basis of which exemplary embodiments of the invention were derived.

Conventional high-pressure filters in HPLC have thin discs with mostly porous sinter inserts. These are placed in a solid, rigid housing and flowed through axially. Such conventional high-pressure filters are mounted between two capillaries. This is expensive and requires sufficient work space to allow this assembly. There is also an increased risk of mechanical damage to the capillary during delicate assembly and disassembly. The described conventional structure of a fluid filter can also result in a not inconsiderable dead volume.

Thus, conventional fluid filters require complicated assembly and installation and expensive replacement. In particular, this may require the manipulation of at least two open ended tools (e.g. two wrenches). In addition, long supply capillaries with unnecessarily large dead volumes are used in such conventional approaches. In addition, with such a fluid filter, a user has to handle a filter element that is sensitive to the touch. In addition, there is a risk of the filter material clogging quickly due to undirected flow. Furthermore, such fluid filters can suffer from short life and frequent replacement.

According to an exemplary embodiment of the invention, a fluid filter with a layered structure with preferably a plurality of microfluidic structures for conducting fluid through the fluid filter is provided. A filter element arranged on the layer structure and preferably held in position by it brings about the actual filtering of fluid that is supplied or removed by means of the microfluidic structures. Advantageously, the fluid flows in and out on only one common side of the layer structure, for example on a single end face thereof. In this way, a very compact fluid filter that is stable under high pressure and easy to handle can be created, which is suitable for many applications. Such a fluid filter can be used very particularly advantageously for an analysis device for analyzing a fluid sample, for example in an HPLC. A fluid filter according to an exemplary embodiment not only meets the demanding pressure requirements of such an application, but also allows a fluid (e.g., a mobile phase) to be filtered without compromising the challenging flow rate accuracy requirements of an HPLC. A complicated and error-prone handling of several capillaries for connection to a fluid filter can advantageously be avoided in that the fluidic coupling of the fluid filter to the analysis device or another target application takes place on a common side both for inlet and outlet.

In particular, according to an exemplary embodiment of the invention, a high-pressure filter based on a metallic microfluidic (MMF) arrangement can be created in which the actual filter material (namely the filter element) is housed in a protected manner within the layered structure, which is preferably designed as an MMF structure. In addition, the inlet and outlet openings are advantageously located on a common, i.e. on the same, side of the fluid filter. This allows for easy assembly by merely placing the interface with inlet and outlet ports on a flat target surface of an analyzer or other fluid processing device.

A fluid filter according to an exemplary embodiment of the invention thus allows particularly simple assembly and an equally uncomplicated exchange. In addition, a reduced dead volume in supply capillaries can be achieved. In addition, the filter element can be protected by the MMF housing. By means of the microfluidic structures in the layered structure, a reliable distribution of the liquid flow over the available filter area and thus a longer service life and thus less frequent replacement can be achieved. The construction of the fluid filter described also allows a particularly simple integration with other fluidic components, such as shear valve heads or pump heads.

Exemplary embodiments of the invention can provide a significant reduction in the system cost of capping the fluid filter when its filter element and laminated construction are contained within a screw-type housing body. Advantageously, the liquid inlet and outlet can be connected to the same side of the fluid filter. A layer structure preferably designed as a multi-layer structure and a layer structure mounted thereon are preferred disc-shaped filter element are used to provide liquid channeling. The type of liquid distribution towards the filter element and/or away from the filter element can be effected spirally or in some other way in order to achieve a two-dimensional widening of the flow of the fluid to be filtered and/or the filtered fluid. A fluid filter can thus be created whose filter element is integrated into a layered structure (in particular a multi-layered structure) and has a liquid inlet and outlet on the same side. This provides a combination of a multi-layer filter cartridge assembly and a support and distribution structure (e.g. in the form of said spiral element) attached to at least one side (preferably both opposite sides) of the filter cartridge.

A front face, axial in the screwing direction, of a fluid filter according to an exemplary embodiment of the invention may be configured for attaching the fluid filter to an analyzer or the like. Layer structures (in particular layers) of the layer structure, preferably including a filter element, can be connected to one another by gluing. A filter cartridge, which may be formed of the laminated structure and the filter element, may be inserted into a case (e.g., a single case body or a plurality of case bodies). For example, the filter insert can be inserted into an annular holder or a ring. The housing (or a housing body) in which the filter element can be inserted can be fixed by screwing (for example for connecting the fluid filter to a flow path).

According to an exemplary configuration of the layer structure, the liquid to be filtered can initially bypass the filter element. Then the direction of flow can be reversed inside the layered structure to enable the fluid to be drained off on the same side of the fluid filter as the fluid is supplied. A flow distribution layer (for example with spiral-shaped grooves and lateral inlets) can then distribute the supplied fluid over an area and thus promote an areal supply of the fluid to be delivered to the filter element.

1 shows the basic structure of an HPLC system as an example of an analysis device 10 according to an exemplary embodiment of the invention, as it can be used, for example, for liquid chromatography.

In the illustrated analyzer 10, an analytical pump fluid drive 20 supplied with solvents from a supply means 25 drives a mobile phase through a sample separation means 30 (such as a chromatographic column) containing a stationary phase. The feed device 25 comprises a first fluid component source 113 for providing a first fluid or a first solvent component A (for example water) and a second fluid component source 115 for providing a different second fluid or a second solvent component B (for example an organic solvent). An optional degasser 27 can degas the solvents provided by the first fluid component source 113 and by the second fluid component source 115 before they are fed to the fluid drive 20 . A sample application unit 40, which can also be referred to as an injector, is arranged between the fluid drive 20 and the sample separation device 30 in order to introduce a sample liquid or fluidic sample into the fluidic separation path. An injection valve 90 can be switched accordingly for this purpose. The injection valve 90 can be in the form of a rotary shear valve which has a stationary stator component 172 and a rotor component 174 which can be rotated and controlled by a control device 70 . For example, the stator component 172 can have microfluidic structures in the form of ports, which can be fluidically connected to the various components 20 , 40 or 30 , etc., and which can extend to a contact surface with the rotor component 174 . For example, the rotor component 174 has one or more grooves, i.e., trough-shaped indentations, at the contact surface that may or may not selectively establish fluidic communication between respective ones of the ports depending on a current relative orientation between the stator component 172 and the rotor component 174.

The stationary phase of the sample separation device 30 is intended to separate components of the sample. A detector 50, which may comprise a flow cell, detects separated components of the sample, and a fractionation device 60 may be provided to dispense separated components of the sample into containers provided for this purpose. Liquids that are no longer required can be discharged into a drain container or into a waste (not shown).

While a liquid path between the fluid drive 20 and the sample separation device 30 is typically under high pressure, the sample liquid is first introduced under normal pressure into an area that is separate from the liquid path, a so-called sample loop, of the sample application unit 40 or the injector then in turn the sample liquid into the high pressure liquid path brings in. During the connection of the sample liquid, which is initially under normal pressure, in the sample loop to the liquid path which is under high pressure, the contents of the sample loop are brought to the system pressure of the analysis device 10 designed as an HPLC. Control device 70 controls the individual components 20, 27, 30, 40, 50, 60, 90 and a proportioning device 101 of sample separation device 10.

The components of the analysis device 10 upstream of the sample application unit 40 in 1 serve to provide a mixture of several different fluids as a solvent composition or mobile phase for the analysis device 10. Two supply lines 109, 111 are fluidic with a respective one of the two solvent containers referred to as fluid component sources 113, 115 for providing a respective one of the fluids or solvent components A and B fluidly coupled. The respective fluid or the respective solvent component A or B is conveyed through the respective feed line 109 or 111, through the degasser 27 to a fluid valve as a proportioning device 101, at which the fluid or solvent components A or B from the feed lines 109, 111 be united with each other. The fluid packages from the supply lines 109, 111 thus flow together at the proportioning device 101 to form a solvent composition. After passing through an optional mixer 103 for mixing the individual solvent components, the latter is fed to the fluid drive 20 .

• - Ein Fluidfilter 100 kann an der analytischen Pumpe 20 angebracht sein, beispielsweise auf einen Pumpenkopf der analytischen Pumpe 20 aufgeschraubt sein. Ein solches Fluidfilter 100 kann Festkörperpartikel aus einer mobilen Phase herausfiltern, die durch Abrieb beim Reziprozieren eines jeweiligen Pumpenkolbens entstehen können.
• - Ein Fluidfilter 100 kann zum Filtern von Fluid direkt stromaufwärts der Probentrenneinrichtung 30 angebracht sein. Ein solches Fluidfilter 100 kann als Vorfilter dienen, das Festkörperpartikel aus einer mobilen Phase bzw. aus einer fluidischen Probe herausfiltern kann, um die schmutzempfindliche Probentrenneinrichtung 30 zu schützen.
• - Ein Fluidfilter 100 kann zum Filtern von Fluid im Bereich des rotatorischen Fluidventils, d.h. an Injektionsventil 90 angebracht sein. Beim Schalten des Injektionsventils 90 kann es zum Erzeugen von Festkörperpartikeln kommen, die durch das dort angeordnete Fluidfilter 100 abgefiltert werden können. Mobile Phase bzw. fluidische Probe kann in diesem Bereich dadurch von Festkörperpartikeln freigehalten werden.
• - Ein Fluidfilter 100 kann zum Filtern von Fluid im Bereich einer Probennadel 120 der Probenaufgabeeinheit 40 angebracht sein. Wenn die Probennadel 120 zum Aufnehmen von fluidischer Probe zwischen einem Probenbehälter und einem Nadelsitz (nicht gezeigt) verfahren wird, kann insbesondere beim Ausbilden einer fluiddichten Verbindung mit dem Nadelsitz ebenfalls Abrieb erzeugt werden. Dieser kann mittels des Fluidfilters 100 abgefiltert werden, sodass mobile Phase bzw. fluidische Probe beim Durchfließen von Probennadel 120 und Nadelsitz vor einer Kontamination mit solchem Abrieb geschützt werden können.

One or more of the components of analyzer 10 according to FIG 1 may be constructed as a fluid filter 100 according to an exemplary embodiment of the invention. Each of these fluid filters 100 can be designed to filter the mobile phase. Furthermore, some of the fluid filters 100 can also be designed to filter fluid samples. According to 1 Fluid filters 100 can be implemented in particular at one or more of the following positions:

• - A fluid filter 100 can be attached to the analytical pump 20, for example screwed onto a pump head of the analytical pump 20. Such a fluid filter 100 can filter out solid particles from a mobile phase, which can be caused by abrasion during reciprocation of a respective pump piston.
• A fluid filter 100 may be mounted directly upstream of the sample separator 30 for filtering fluid. Such a fluid filter 100 can serve as a pre-filter which can filter out solid particles from a mobile phase or from a fluid sample in order to protect the sample separation device 30 which is sensitive to dirt.
• - A fluid filter 100 can be attached to the injection valve 90 for filtering fluid in the area of the rotary fluid valve. When the injection valve 90 is switched on, solid particles can be produced, which can be filtered out by the fluid filter 100 arranged there. In this way, the mobile phase or fluidic sample can be kept free of solid particles in this area.
• - A fluid filter 100 can be attached to filter fluid in the area of a sample needle 120 of the sample application unit 40 . When the sample needle 120 is moved between a sample container and a needle seat (not shown) to take up fluidic sample, abrasion can also be generated, in particular when a fluid-tight connection is formed with the needle seat. This can be filtered off by means of the fluid filter 100 so that the mobile phase or fluidic sample can be protected against contamination with such abrasion when it flows through the sample needle 120 and needle seat.

Referring to 2 until 6 is described below how the in 1 Schematically illustrated fluid filter 100 can be constructed, for example:

2 10 shows an exploded view of a fluid filter 100 according to an exemplary embodiment of the invention. 3 10 shows another exploded view of the fluid filter 100 according to FIG 2 . 4 shows the fluid filter 100 according to FIG 2 and 3 in an assembled state in a cross-sectional view.

The embodiment according to 2 until 4 thus relates to the illustrated fluid filter 100 for filtering a fluid, such as a mobile phase or a fluidic sample. It is particularly preferred to implement such a fluid filter 100 in an analysis device 10, as is the case, for example, in 1 is shown. However, other applications of the fluid filter 100 are possible.

The fluid filter 100 shown has a planar layer structure 102 which is made up of structured metal foils or small metal plates which are connected to one another. The latter form layer structures 112 provided as metal layer structures, which can be connected to one another integrally by means of diffusion bonding. As in 2 until 4 As can be seen, each of the layer structures 112 has microfluidic structures 104 which are designed to supply or drain said fluid. Some of the microfluidic struc Structures 104 are formed as grooves in the respective layer structures 112. FIG. These grooves are partly designed as ring grooves (see connection layer structure 122 in 3 ), partly as longitudinal grooves (see lateral bypass layered structure 132 in 2 ) and partly as spiral grooves (see intermediate layer structure 126 in 2 and final layer structure 124 in 3 ) educated. Others of the microfluidic structures 104 are formed as through holes in the respective layer structures 112 (see layer structures 122, 132, 126, 128 in 2 or. 3 ). In the interconnected state of the layered structures 112, which is best seen in 4 can be seen, the individual microfluidic structures 104 of the layer structures 112 are aligned with one another, so that starting from a fluid inlet 108 through the microfluidic structures 104 forming a flow path with one another to a fluid outlet 110, a continuous fluidic connection is formed, which also includes a porous filter element 106 included.

Said filter element 106 of the fluid filter 100 is used for the actual filtering of the fluid flowing through the microfluidic structures 104 between the fluid inlet 108 and the fluid outlet 110. The filter element 106 can be designed as a sintered body, which is formed from a metal powder bonded under pressure and high temperature and has intermediate spaces for Has flow through of the fluid. Solid particles, on the other hand, cannot find a continuous path through the filter element 106 and are therefore filtered out of the fluid. The filter element 106 can be pressed into the layer structure 102, in particular into an annular receiving layer structure 128. Due to its structure, the fluid filter 100 shown is suitable for pressure-resistant operation up to at least 2000 bar. The fluid filter 100 can therefore also be used advantageously in an HPLC.

The fluid supply 108 already mentioned for supplying the fluid to be filtered and said fluid discharge 110 for discharging the filtered fluid are advantageously arranged on the same side of the layered structure 102, namely on a fluid-coupling end face 176 of the layered structure 102 and thus of the fluid filter 100. Fluid supply 108 and Fluid drain 110 are fluidically coupled to the microfluidic structures 104 . Since the fluid supply 108 and the fluid discharge 110 are provided on the same side of the filter element 100, it is sufficient for the fluidic coupling of the filter element 100 to connect the filter element 100 flatly to a counterpart, for example an analysis device 10, on the fluid coupling end face 176.

The fluid filter 100 advantageously has a housing body 114 made, for example, from a metal (such as corrosion-resistant steel), which is designed as a hollow screw. A cavity 178 is therefore formed in the interior of the housing body 114, in which the layer structure 102 and the filter element 106 are arranged. On the outside, the housing body 114 is provided with a thread 116, which is an external thread in the illustrated embodiment. Thread 116 is used to screw fluid filter 100 to a fluidic component (not shown in FIG 2 until 4 , for example the analyzer 10 according to FIG 1 or its analytical pump 20, injection valve 90, sample needle 120 or sample separator 30). In its drive end face 180 opposite the fluid coupling end face 176, the housing body 114 has a drive 118 for driving the fluid filter 100 in rotation. More precisely, the drive 118 is formed as a non-rotationally symmetrical depression in the drive end face 180, in the exemplary embodiment shown as a hexagonal depression. Using an inversely shaped bit of a screwdriver (not shown) or a motor-driven screwing tool (in particular a cordless screwdriver), the fluid filter 100 can be driven in rotation by engaging in the drive 118, as a result of which a screw connection can be formed between the fluid filter 100 and the counterpart by means of the thread 116. Conversely, to replace the fluid filter 100 or a component thereof, the fluid filter 100 can be unscrewed from the counterpart.

Advantageously, the layer structure 102 together with the filter element 106 can be inserted into the housing body 114 in an exchangeable manner as a one-piece component that can be handled. If the filter capacity of the filter element 106 is exhausted because the filter element 106 has filtered out a correspondingly large quantity of solid particles from the fluid, it may be sufficient to remove the one-piece manageable component as a whole from the housing body 114 and replace it with an unloaded new one-piece manageable component Layer structure 102 including filter element 106 to replace. The case body 114 can then be reused. Alternatively, once the filter capacity of a filter element 106 has been exhausted, the entire filter element 106 can also be replaced, i.e. the layer structure 102 together with the filter element 106 and housing body 114.

The structural and functional design of the layered structure 102 is explained below with reference to FIG 2 until 4 described in more detail:

The fluid coupling face 176 forms an outer side of the layered structure 102 and is formed by a connection layered structure 122 of the layered structure 102 . at the connection Layer structure 122, the fluid supply 108 and the fluid discharge 110 are provided as fluid interfaces accessible to the outside. As best in 3 As can be seen, the connection layer structure 122 as a microfluidic structure 104 has a central through hole which forms the fluid drain 110 . In addition, two further through-holes located radially further outwards are formed in the connection layer structure 122 as further microfluidic structures 104 . These two further through holes represent the fluid supply line 108 and are fluidically coupled to a circular annular groove which is arranged on the fluid coupling face 176 which is accessible to the outside. By dividing the fluid supply 108 over a number of through-holes, a uniform flow through a number of flow paths can be achieved. Clearly, hydraulic forces can be spatially distributed through the symmetrical distribution of the flow. In addition, splitting the flow promotes flushability of the channels. Again referring to 3 it can be seen that the two radially further outward through-holes and the circular annular groove surround the central through-hole radially. Due to the configuration described, the connection layer structure 122 is advantageously configured such that, regardless of a rotational position of the fluid filter 100 at the end of a screwing-in process, the fluid inlet 108 and the fluid outlet 110 are fluidically aligned with corresponding fluid connections of a fluidic component to be fluidically coupled to the fluid filter 100. This is because the central through-hole is always in the same position, regardless of an angular position of the fluid filter 100 . The rotationally symmetrical annular groove ensures that a fluidic connection with the fluid supply 108 can always be formed, also independently of the angular position of the fluid filter 100 after it has been screwed in at the radius of the annular groove. It should be noted that in other exemplary embodiments, the functions of the fluid inlet 108 and fluid outlet 110 can be reversed from the configuration described.

After the fluid to be filtered has been guided through the fluid supply 108 and through the connection layer structure 122, it reaches a lateral deflection layer structure 132 of the layer structure 102. The latter has a microfluidic structure 104 for redirecting a flow of the fluid in the lateral direction, which is best in 2 can be seen. The microfluidic structures 104 of the lateral bypass layered structure 132 initially have two through holes that are fluidically coupled to the radially outer through holes of the connector layered structure 122 . After flowing through the through-holes of the lateral bypass layered structure 132, the fluid to be filtered flows straight radially outwards along two longitudinal grooves of the lateral bypass layered structure 132 connected to said through-holes, see FIG 2 . This makes it possible to first flow around the filter element 106, as will be described in more detail below.

The fluid to be filtered then flows through an intermediate layer structure 126 of the layer structure 102. Starting from the longitudinal grooves of the lateral diversion layer structure 132, the fluid flows through two through holes of the intermediate layer structure 126. Another, in 2 The spiral groove that can be seen in a surface of the intermediate layer structure 126 and a central through-hole of the same initially play no role for the fluid to be filtered and are described in more detail below in connection with the return of the filtered fluid.

After flowing through the two radially outer through-holes of the intermediate layer structure 126, the fluid to be filtered flows through two further through-holes of a receiving layer structure 128 that are fluidically coupled to the two through-holes mentioned. The receiving layer structure 128 of the layered construction 102 has a central receiving opening 130 which is designed to receive the filter element 106 in the circumferential direction. The filter element 106 can be pressed into the central receiving opening 130 and thereby embedded in the layer structure 102 over its entire circumference. The fluid to be filtered first flows around the filter element 106 through the two through-holes of the receiving layer structure 128 that are located radially further to the outside.

The fluid to be filtered then reaches an end layer structure 124 of the layer structure 102, the microfluidic structures 104 of which are the only ones of the layer structures 112 that do not have through holes, but rather a spiral groove and two fluid connection points fluidically coupled thereto in fluid connection with said through holes of the receiving layer structure 128. Said Spiral groove faces and fluidly couples with a skin surface of the porous or foraminous filter element 106 in the intake sheet structure 128 . Fluid to be filtered flowing in from the receiving layer structure 128 flows radially inward along the spiral groove and thus enters into two-dimensional fluid exchange with said skin surface of the filter element 106. As a result, the fluid flowing in from the fluid supply 108 undergoes a flow direction reversal before being filtered by the filter element 106 subjected, namely according to 4 from a bottom-up flow direction before filtering to a top-down flow direction during and after filtering. In other words, the fluid to be filtered first flows radially outward around the filter element 106 and then flows through the filter element 106 from its rear side. As a result, the fluid is diverted back through the filter element 106 in the direction of the fluid discharge 110 . Advantageously, the spiral groove of the end layer structure 124 ensures a planar exchange of the fluid to be filtered with the filter element 106, as a result of which the fluid is filtered homogeneously and efficiently by the filter element 106. Thus, the end layer structure 124 with its spiral groove (or alternatively any other flat groove, for example a meandering groove and/or a zigzag groove) has a microfluidic structure 104, which directly adjoins the filter element 106 on the fluid inlet side and thus has a flat, expanded fluid exchange surface between the filter element 106 and the fluid to be filtered forms.

When flowing through the filter element 106, any solid particles of the fluid to be filtered remain on the filter element 106, whereas liquid or gaseous components can pass through the filter element 106 and form the filtered fluid. The filtered fluid then flows back through the intermediate layer structure 126. On a main surface of the filter element 126, where the filtered fluid emerges, the intermediate layer structure 126 has a further microfluidic structure 104 for promoting a planar fluid exchange with the filter element 106. This further microfluidic structure 104 is according to FIG 2 formed as a spiral groove in a main surface of the intermediate layer structure 126, which is directly adjacent to the filter element 106 on the fluid outlet side. The spiral groove of the intermediate layer structure 126 thus forms a fluid exchange surface which is expanded over a wide area. The filtered fluid flows radially inward along the spiral groove of the intermediate layer structure 126 and then flows through a central through-hole of the intermediate layer structure 126 that is fluidically coupled to the spiral groove the filter element 106, resulting in a homogeneous and efficient radial collection of the filtered fluid to promote a backflow towards the fluid drain 110. Thus, the intermediate layer structure 126 with its spiral groove (or alternatively any other flat groove, for example a meandering groove and/or a zigzag groove) has a microfluidic structure 104 which directly adjoins the filter element 106 on the fluid outlet side and thus has a flat, expanded fluid exchange surface between the filter element 106 and the intermediate layer structure 126 forms.

The provision of an areally expanded fluid exchange surface on one or preferably both main surfaces of the filter element 106, as described, ensures an optimal distribution of the fluid over the surface of the filter element 116 away. Webs between the adjacent groove sections of the surface groove (in particular the spiral groove shown) support the surface of the filter element 106 and therefore ensure particularly good pressure stability.

The filtered fluid then flows through central through-holes of the lateral bypass sandwich 132 and the port sandwich 122 and is thereby conveyed toward the fluid drain 110 .

The layered structure formed as a planar filter assembly is an MMF structure built into the housing body 114 formed as a threaded portion. Advantageously, the fluid filter 100 has its inlet and outlet (i.e. fluid inlet 108 and fluid outlet 110) on a common, i.e. on the same side. Consequently, the fluid filter 100 can be screwed with the threaded part against a flat surface containing a corresponding inlet and outlet.

The microfluidic structures 104 are designed in the connection layer structure 122 in such a way that the fluid filter 100 can be screwed on without the need for a specific rotational orientation. In the example shown, this is achieved by a central channel and a circular channel surrounding it. Together, these microfluidic structures 104 have only a small dead volume. Of course, a design with a predetermined target rotational orientation is also possible, for example grooves, bores or other geometrically defined shapes. The lateral bypass layered structure 132 and the intermediate layered structure 126 form an MMF channel geometry which guides the fluidic channels around the actual filter pad, i.e. filter element 106. The filter element 106 can be designed, for example, as a sintered part or as a stacked network part with a specific pore size. The lateral bypass layered structure 132 and the end layered structure 124 contact the end faces of the filter element 106. Furthermore, optimum flow can be achieved by a spiral or meander channel structure of the layered structures 132, 124. The receiving layered structure 128 forms a radial housing of the filter element 106 and, due to its somewhat larger diameter, also serves as mechanical protection against falling out.

The fluid filter 100 has the fluidic inlet and the fluidic outlet on the same side, preferably on an axial front side in the screwing direction of the housing body 114 designed as a hollow screw for attachment and closing ßen the fluid filter 100. The functional filter is preferably a filter insert from the layered structure 102 shown and the filter element 106 and is formed from a plurality of layers which enclose the filter element 106). The individual layers of the filter insert can preferably be connected to one another by diffusion welding, so that the filter insert results as an integral part. The filter cartridge of layered construction 102 and filter element 106 can be inserted into housing body 114, which can be attached to a target position by screwing the housing body. The layer structure 102 can be produced by means of MMF.

A sealing structure, not shown, against which the fluid filter 100 is screwed, can be implemented with a pressed-in ring seal, with an adaptive seal or with a printed seal, for example.

5 10 shows an exploded view of a fluid filter 100 according to another exemplary embodiment of the invention.

5 10 also shows a fluid filter 100 for filtering a fluid, which has a layered structure 102 with microfluidic structures 104. These are used to supply and drain the fluid. Furthermore, a filter element 106 for filtering the fluid supplied by means of the microfluidic structures 104 can be provided. This can be used in the layer structure 102 . As shown, a fluid supply 108 for supplying the fluid to be filtered and a fluid discharge 110 for discharging the filtered fluid can be arranged on the same side of the layered structure 102 and can be fluidically coupled to the microfluidic structures 104 .

According to 5 a non-rotationally symmetrical shaping of the layer structure 102 is realized to provide rotation protection. This causes a nose 188. The fluid filter 100 according to FIG 5 designed as a washer that can be fixed to a target position by means of a screw or other fastener. The screw or the fastening element (not shown) can be passed through a central through-opening 198 of the layered structure 102 .

6 12 shows a fluid filter 100 according to yet another exemplary embodiment of the invention.

The fluid filter 100 according to FIG 6 has a plurality of filter elements 106 . Each of the filter elements 106 can be designed to filter the fluid supplied by means of microfluidic structures 104 and can be arranged on the layered structure 102 . The filter elements 106 are in accordance with 6 circular or star-shaped support body 160, more precisely on arms 162 of such a support body 160. By rotating the support body 160 (see rotation arrow 164), the filter elements 106 can also be rotated. As a result, a respective one of the filter elements 106 can be brought into position for filtering the supplied fluid by means of rotation.

The embodiment according to 6 thus relates to a planar fluid filter 100 with fluid inlet 108 and fluid outlet 110 (not shown) on one side. In this exemplary embodiment, several filter inserts are provided, in which the filter elements 106 used can simply be unscrewed, turned further and screwed tight again, similar to a revolver drum. In this way, used filter elements 106 can also be identified mechanically, for example using corresponding imprints. A plurality of filter elements 106 can thus be arranged in a turret component of any shape, which can be rotated in order to successively bring the individual filter elements 106 into operative connection with the respective microfluidic structure 104 of the layered construction 102 .

As illustrated, the support body 160 can be cross-shaped or star-shaped, with each arm 162 of the support body 160 being equipped with an associated filter element 106 (or with a plurality of filter elements 106). If a filter element 106, which was previously in operative connection with the layer structure 103, is exhausted in terms of its filter capacity or is completely loaded with solid particles, the carrier body 160 can be rotated until another arm 162 with another filter element 106 is aligned with the layer structure 102 and is thus brought into operative connection with the layer structure 102 . The fluid filter 102 can then continue to be operated with this other filter element 106 . Only when all filter elements 106 of the carrier body 160 have been exhausted in terms of their filter capacity or are completely loaded with solid particles can the entire carrier body 160 be replaced or its filter elements 106 renewed.

7 10 shows a perspective view of a fluid filter 100 according to yet another example embodiment of the invention.

The embodiment according to 7 differs from the embodiment according to 6 in particular by the fact that according to 7 a carrier body 160 with six arms 162 is provided, with a respective filter element 106 being provided on each of the six arms 162 .

It should be noted that the term "comprising" does not exclude other elements and that the "a" does not exclude a plural. Elements that are described in connection with different exemplary embodiments can also be combined. It should also be noted that any reference signs in the claims should not be construed as limiting the scope of the claims.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 0309596 B1 [0002]

Claims (20)

Fluid filter (100) for filtering a fluid, in particular in an analysis device (10), the fluid filter (100) having: a layer structure (102) which has at least one microfluidic structure (104) for supplying and removing the fluid; and a filter element (106) which is designed to filter the fluid supplied by means of the at least one microfluidic structure (104) and which is arranged on and/or in the layer structure (102); wherein a fluid supply (108) for supplying the fluid to be filtered and a fluid discharge (110) for discharging the filtered fluid are arranged on the same side of the layered structure (102) and are fluidically coupled to the at least one microfluidic structure (104). Fluid filter (100) according to claim 1 , wherein the layer structure (102) is formed from a plurality of layer structures (112) connected to one another. Fluid filter (100) according to claim 1 or 2 , wherein the layer structure (102) is formed from a plurality of metal layer structures. Fluid filter (100) according to any one of Claims 1 until 3 , wherein a microfluidic structure (104) of the layered construction (102) directly adjacent to the filter element (106), in particular on the fluid inlet side and/or fluid outlet side, forms at least one flat, widened fluid exchange surface, in particular designed as a flat groove structure with webs arranged in between. Fluid filter (100) according to any one of Claims 1 until 4 , wherein the at least one microfluidic structure (104) has at least one through hole through at least one layer structure (112) of the layer structure (102) and/or at least one groove, in particular at least one spiral, meandering or elongated groove, in a main surface of at least one layer structure ( 112) of the layer structure (102). Fluid filter (100) according to any one of Claims 1 until 5 wherein the filter element (106) comprises a sintered body or a mesh stack. Fluid filter (100) according to any one of Claims 1 until 6 , wherein the filter element (106) is fully embedded in the layer structure (102). Fluid filter (100) according to any one of Claims 1 until 7 , Having a housing body (114) in which the layer structure (102) and the filter element (106) are arranged. Fluid filter (100) according to claim 8 , wherein the housing body (114) has a thread (116), in particular an external thread, for screwing to a fluidic component to be coupled to the fluid filter (100). Fluid filter (100) according to claim 8 or 9 , wherein the housing body (114) has a drive (118) for driving the fluid filter (100) in rotation. Fluid filter (100) according to any one of Claims 8 until 10 , wherein the layered structure (102) together with the filter element (106) is inserted into the housing body (114) as a replaceable, one-piece component that can be handled. Fluid filter (100) according to any one of Claims 1 until 11 , A connection layer structure (122) of the layer structure (102) having the fluid supply (108) and the fluid discharge (110). Fluid filter (100) according to claim 12 , having at least one of the following features: the connection layer structure (122) being designed in such a way that, regardless of a rotational position of the fluid filter (100), the fluid supply (108) and the fluid discharge (110) can be fluidically coupled to corresponding fluid connections of one with the fluid filter (100) are aligned fluidically to be coupled fluid component; wherein the connection layer structure (122) as a microfluidic structure (104) has a, in particular central, through-hole and an annular groove fluidically coupled to at least one further through-hole, in particular to two further through-holes, in particular surrounding the central through-hole. Fluid filter (100) according to any one of Claims 1 until 13 , having at least one of the following features, wherein an end layer structure (124) of the layer structure (102) is designed to subject the fluid flowing in from the fluid supply (108), in particular before filtering by means of the filter element (106), to a flow direction reversal and , in particular through the filter element (106), back in the direction of the fluid discharge (110), with the end layer structure (124) in particular having a microfluidic structure (104) for promoting a planar fluid exchange with the filter element (106), in particular by means of an as microfluidic structure (104) formed in a helical groove in a major surface of the final layered structure (124); wherein an intermediate layer structure (126) of the layer structure (102) is designed to promote a fluid exchange between the filter element (106) and the fluid discharge (110), in particular the intermediate layer structure (126) a has a microfluidic structure (104) for promoting a planar fluid exchange with the filter element (106), in particular by means of a microfluidic structure (104) designed as a spiral groove in a main surface of the intermediate layer structure (126); wherein a receiving layer structure (128) of the layered construction (102) has a receiving opening (130) for the peripheral receiving of the filter element (106); wherein a lateral diversion layer structure (132) of the layered construction (102) has a microfluidic structure (104) for, in particular rectilinear, diversion of a flow of the fluid in a lateral, in particular radial, direction; wherein a shape of the layered structure (102) is designed to provide anti-rotation protection; having at least one further filter element (106) which is designed to filter the fluid supplied by means of the at least one microfluidic structure (104) and which is to be arranged on and/or in the layered structure (102), wherein in particular the filter element (106) and the at least one further filter element (106) is movably, in particular rotatably, attached so that a respective one of the filter elements (106) can be brought into position for filtering the supplied fluid; configured for pressure-resistant operation up to at least 1000 bar, in particular up to at least 2000 bar. Analysis device (10) for analyzing a fluidic sample, wherein the analysis device (10) has at least one fluid filter (100) according to one of Claims 1 until 14 having. Analysis device (10) according to claim 15 , designed as a sample separator; and comprising an analytical pump (20) for driving a mobile phase and a fluidic sample introduced into the mobile phase, and a sample separator (30) for separating the fluidic sample introduced into the mobile phase. Analysis device (10) according to Claim 16 , further comprising at least one of the following features: wherein the fluid filter (100) is designed for filtering the mobile phase; wherein the fluid filter (100) is attached to the analytical pump (20); wherein the fluid filter (100) for filtering fluid is mounted upstream of the sample separator (30); wherein the fluid filter (100) is mounted for filtering fluid in the region of a rotary fluid valve (90); wherein the fluid filter (100) is mounted for filtering fluid in the region of a sample needle (120). Analysis device (10) according to one of Claims 15 until 17 , further comprising at least one of the following features: the analyzer (10) is configured to analyze at least one physical, chemical and/or biological parameter of the fluidic sample; the analysis device (10) is configured as a sample separation device for separating the fluidic sample; the analysis device (10) is a chromatography device, in particular a liquid chromatography device, a gas chromatography device, an SFC (supercritical liquid chromatography) device or an HPLC (high performance liquid chromatography) device; the analysis device (10) is configured as a microfluidic device; the analysis device (10) is configured as a nanofluidic device; the sample separation device (30) is designed as a chromatographic separation device, in particular as a chromatography separation column; the analytical pump (20) is configured to propel the mobile phase and the fluidic sample under high pressure; the analytical pump (20) is configured to propel the mobile phase and the fluidic sample at a pressure of at least 500 bar, in particular at least 1000 bar, more in particular at least 1500 bar; the analyzer (10) has an injector (40) for injecting the fluidic sample into the mobile phase; the analysis device (10) has a detector (50) for detecting the analyzed, in particular separated, fluidic sample; the analysis device (10) has a fractionator (60) for fractionating separated fractions of the fluidic sample. Method for producing a fluid filter (100) for filtering a fluid, in particular in an analysis device (10), the method having: providing a layered structure (102) with at least one microfluidic structure (104) for supplying and discharging the fluid; Arranging a filter element (106), which is designed to filter the fluid supplied by means of the at least one microfluidic structure (104), on and/or in the layer structure (102); and arranging a fluid supply (108) for supplying the fluid to be filtered and a fluid discharge (110) for discharging the filtered fluid on the same side of the layer structure (102), the fluid supply (108) and the fluid discharge (110) be fluidically coupled to the at least one microfluidic structure (104). procedure according to claim 19 , wherein the method comprises attaching the filter element (106) to the layer structure (102) and/or attaching metal layer structures of the layer structure (102) to one another by means of diffusion bonding.

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