Measuring device, fluid supply system and method for analyzing a sample

Abstract

The invention relates to a measuring device for analyzing a fluidic sample, wherein the measuring device comprises a sample chamber, a piston movable therein, a drive device for automatically moving the piston, and at least one measuring instrument for measuring a measured variable on a sample located in the sample chamber. The invention further relates to a fluid supply system having such a measuring device and to an associated method.

Description

[0001] Measuring device, fluid supply system and

[0002] Method for analyzing a sample

[0003] The invention relates to a measuring device for analyzing a fluidic sample, a fluid supply system and a method for analyzing a sample.

[0004] Supplying diverse consumers with various fluidic media occurs in a wide range of scenarios. One example is a typical public water supply system, where drinking water is usually monitored for compliance with various quality criteria before being fed into a public distribution network for delivery to private and commercial customers. Other possible applications include supplying plants that carry out chemical processes, such as synthesis, with the necessary reactants. Various measuring instruments exist for measuring different parameters of a fluidic medium such as water. These instruments are typically designed to be immersed in a fluid flow and surrounded by the fluid.The measuring instrument then has, for example, two opposing windows between which the fluid flows, whereby a measurement quantity between these two windows is determined, for example, by optical measuring methods.

[0005] It is an object of the invention to provide a measuring device for analyzing a fluidic sample which, compared to known designs, is alternatively or better designed, for example, easier to handle. It is a further object of the invention to provide a fluid supply system with such a measuring device. It is also an object of the invention to provide a method for analyzing a sample. This is achieved according to the invention by a measuring device, a fluid supply system, and a method according to the respective main claims. Advantageous embodiments can be found, for example, in the respective dependent claims. The content of the claims is incorporated into the description by express reference. The invention relates to a measuring device for analyzing a fluidic sample. The measuring device has a sample chamber for receiving the sample.The measuring device preferably comprises a piston, which is preferably movable within the sample chamber. In particular, when the piston moves in a first direction, the sample is drawn into the sample chamber. In particular, when the piston moves in a second direction, which differs from the first direction, the sample is pushed out of the sample chamber. The measuring device preferably comprises a drive unit, in particular an electric, pneumatic, and / or hydraulic drive unit, for moving, in particular automatically, the piston. Furthermore, the measuring device preferably comprises one or more measuring devices. Each measuring device is specifically designed to optically measure at least one parameter of the sample located in the sample chamber.

[0006] With such a measuring device, it is no longer necessary to position measuring instruments within a fluid flow. Consequently, these instruments are no longer exposed to the fluid flow. In known designs, it has been observed that exposure to the measuring instrument by the fluid flow can lead to contamination of the instrument. For example, windows through which a measuring jet passes can become so dirty that further measurements are no longer reliable. Prior art solutions exist that require, for instance, the laborious removal of the measuring instrument from the fluid flow, or that use elaborate small parts such as wipers to clean the windows located in the fluid flow. Such complex mechanisms are unnecessary with the design described herein.In the measuring device described herein, the measuring instrument is advantageously arranged outside the sample chamber and thus does not come into contact with the sample. In particular, preferably the entire measuring instrument, or preferably all measuring instruments, are arranged entirely outside the sample chambers. This prevents contamination of the measuring instrument. The sample chamber can be easily cleaned by the piston, and further functionalities are enabled, which will be discussed in more detail below. The sample chamber can, in particular, have a main connection, which may be designed as an opening in the sample chamber. Through such a main connection, fluid can flow into and / or out of the sample chamber, especially when the piston is moved. This main connection can, for example, be designed as a connector.This can, for example, establish a fluidic and / or mechanical connection to a valve such as a multi-valve.

[0007] A measuring device is understood to be, in particular, a device designed to perform measurements on a fluidic sample. A fluidic sample can be, in particular, a liquid or a gaseous sample. A liquid sample can be, for example, water, or it can be, for example, a substance used as a reactant in a chemical process. A gaseous sample can be, for example, ambient air, a specific gas, or a gas mixture. The sample is typically a portion of a larger fluid flow, which is extracted from the flow for measurement. After the measurement process, the sample can be returned to the fluid flow, or it can be further processed or disposed of in some other way.

[0008] The sample chamber typically provides a specific volume to hold the sample. The measurement is typically performed on the volume or sample contained within the sample chamber. The piston's movement within the sample chamber can be used to draw sample into the chamber, particularly before a measurement, and to expel sample from the chamber, particularly after a measurement. Alternatively, the sample can be held stationary within the sample chamber to perform the measurement. In this case, the sample typically only contacts one wall of the sample chamber and the piston, thus preventing contamination of the measuring instrument.

[0009] The drive unit can move the piston, in particular automatically. Automatic movement means, in particular, that the piston is not moved by human muscle power, but by a dedicated, typically electrically operated device. Specifically, an electric motor, an electromagnet, a pneumatically or hydraulically driven cylinder, and / or a pneumatic or hydraulic motor can be used for this purpose. The drive unit can, for example, be controlled by an electronic device that can send a signal to move the piston in the first or second direction. Alternatively or additionally, the drive unit can move the piston in response to a manual input, such as pressing a button or selecting an option in a user interface.The drive device can therefore be, in particular, an electric and / or automatic drive device. However, a manual drive device is also possible. A manual drive device can be specifically designed to be operated by human muscle power.

[0010] The piston is typically moved in both directions until it reaches a stop or end position. An end position can be predefined, for example. In particular, it can be chosen such that all areas where a measuring device or devices take measurements are traversed when the piston moves in one direction. In the first direction, the piston is typically moved until it reaches a first stop or end position where the sample chamber is completely or at least predominantly filled. In the second direction, the piston is typically moved until it reaches a second stop or end position where the sample chamber is emptied or at least largely emptied. A stop is understood to mean, in particular, a mechanical limitation on further movement of the piston.An end position can be identical to a stop, but it can also be defined before a stop when the piston moves towards the stop.

[0011] A measuring device is typically designed to measure one or more quantities. Optical measurements are typically used for this purpose. These measurements involve directing a measuring beam into the sample chamber and detecting the light emanating from the chamber. This light can be transmitted, scattered, or reflected, for example. Alternatively, an excitation beam may be used to induce a chemical reaction or fluorescence in the sample, and the resulting light may be detected. Depending on the design, the measuring device may have only one measuring device, or it may have two or more. This allows for different configurations to measure various quantities and thus adapts the device to different tasks.

[0012] In an advantageous embodiment, the measuring device has one or more holders. Preferably, one, some, or all of the holders each hold a measuring instrument or several measuring instruments. The holders are, in particular, detachably attached to another component of the measuring device. The holders thus serve to secure the measuring instruments in such a way that the respective measuring instrument can be detached by detaching the holder. This allows for easy replacement of measuring instruments. For example, a holder with a measuring instrument can be removed when the measuring instrument is no longer needed, when it is to be replaced by another, or when the measuring instrument is to be removed for maintenance or repair. The measuring instruments can be permanently or detachably attached to the respective holder.It may also be provided that one bracket is attached to another, whereby this is also understood here as attachment to the other component of the measuring device, namely as indirect attachment. Typically, at least one bracket is directly attached to the other component of the measuring device. The other component of the measuring device may be, for example, a base plate, a base body, or a similar structure, to which, for example, the sample chamber may also be attached. Other components, such as the valve described below, may also be attached to the other component.

[0013] In particular, one, some, or all of the supports can be designed to surround the sample chamber. This can specifically mean that the sample chamber extends through a particular support. Alternatively, one, some, or all of the supports can be designed to be spaced away from the sample chamber. This can specifically mean that there is a gap between the respective support and the sample chamber. In other words, the support does not contact the sample chamber. This can, in particular, allow for easy removal and replacement of the support, especially without risk of damaging the sample chamber. A support can also be in contact with the sample chamber. The respective support can, in particular, extend completely around the sample chamber.

[0014] In particular, it may be provided that one, some, or all of the brackets are ring-shaped. It may also be provided that one, some, or all of the brackets are rectangular or square. This can apply in particular to the top view and / or cross-section. This allows for adaptation to the different requirements of measuring instruments. A ring shape, for example, can be circular or oval.

[0015] In particular, the supports may be designed to be removable and attachable parallel to a longitudinal dimension of the sample chamber. It may also be designed to be removable and attachable only in this manner and / or not removable and / or attachable transversely to the longitudinal dimension of the sample chamber. A longitudinal dimension of the sample chamber is typically defined by a central axis, which may, for example, be the center point of a round, square, or rectangular cross-section, or any other cross-section. The longitudinal dimension may also be identical to or parallel to an axis along which the piston is movable. Typically, the piston is movable only in one dimension.Removing and reattaching the supports parallel to this longitudinal extension has proven particularly advantageous, as this requires the least relative movement between the support and the sample chamber during an immediate proximity of the support and sample chamber, and is therefore easy to perform and avoids damage to the sample chamber.

[0016] In an advantageous embodiment, the measuring device has a mounting device to which each of the holders can be attached. The mounting device can be designed, in particular, to fix the attached holder in its position and / or orientation. For this purpose, clip connections, screw connections, plug connections, or other connection options can be used, for example. Adjacent parts can also be provided. Typically, only one holder is attached to the mounting device at a time. Other holders can, for example, be attached to this holder. However, the mounting device is advantageously designed so that it is possible to attach any of the measuring device's holders to it, thus allowing for the replacement of the holder attached to the mounting device.

[0017] Preferably, each bracket, or at least one or several brackets, has a fastening device to which each other bracket can be attached. This essentially corresponds to the functionality described above with regard to the fastening device. In particular, this allows the order in which the brackets are attached to be irrelevant, as it is always possible to attach another bracket.

[0018] In particular, the fastening devices can be designed to be identical. This allows the described functionality of interchangeable brackets to be achieved in a particularly advantageous way. Typically, one bracket will fit another bracket or another component of the measuring device.

[0019] Preferably, each fastening device has a bearing surface which may, in particular, point towards a holder to be attached to the respective fastening device, and / or which may contact a holder to be attached to the respective fastening device, and / or which may, in particular, be oriented transversely to a longitudinal extent of the sample chamber. Alternatively or additionally, it may be designed transversely to a direction in which the holders can be removed and attached. Such a bearing surface may, in particular, serve to ensure that a holder is positioned flush against the surface.According to a preferred embodiment, the fastening devices each have a circumferential projection for the attachment of a holder, wherein the circumferential projection extends, in particular, parallel to a longitudinal dimension of the sample chamber and / or parallel to a direction in which the holders can be removed and attached. The projection can be arranged radially inside a holder to be attached to the fastening device. This can particularly mean that, in the assembled state, a holder is arranged at least partially radially outside a projection of another holder or fastening device. The projection can be annular or rectangular in plan view. It can enclose the sample chamber. Such a projection can stabilize a holder, with another holder abutting it flush.In particular, it can be provided that when holders are joined together, the fastening devices acting as described define a position and / or orientation of the holders relative to each other, possibly with the exception of rotation about a longitudinal axis, which may, for example, be identical to or at least parallel to a longitudinal extent of the sample chamber and / or to a direction in which the holders can be removed and attached. Such rotation may be possible without restriction, for example, with round holders. With square or other rectangular holders, rotation in predefined orientations may be possible. Alternatively, it may also be provided that the fastening devices are designed in such a way that only one specific orientation is possible at a time.

[0020] According to an advantageous embodiment, the measuring device has a base body from which the sample chamber preferably projects and / or to which a mounting device is preferably attached. The base body can, in particular, provide fundamental stability to the measuring device. The base body can, for example, be the other component of the measuring device mentioned above, to which one or more brackets are attached or can be attached.

[0021] According to an advantageous embodiment, the measuring device has a cover, in particular for darkening and / or providing a light-tight seal for the space between the sample chamber and one or more supports and / or measuring instruments. This prevents light from entering the chamber and negatively affecting the measurements. The cover can be detachably attached to a support. The cover can be designed, for example, as a film, a cloth, a solid element, or a flexible element. In particular, at least one measuring instrument can have a light source. This light source can be designed, in particular, to generate a light beam and introduce it into the sample chamber. Such a light beam can, for example, be transmitted, scattered, and / or reflected within the sample.The light beam can also induce fluorescence in the sample, and / or it can induce a chemical reaction in the sample, thereby altering its optical properties. Light emanating from the sample can then be advantageously used for measurement. In particular, a light source can be configured to introduce a light beam through a transparent region of the sample chamber. This region can be a partial region of the sample chamber, i.e., the sample chamber can be designed such that only part of it is transparent while the rest is opaque. Alternatively, the sample chamber can be completely transparent. The transparency can refer in particular to visible light or to light used for measurement, especially light from the light beam.

[0022] For example, transparency can refer to ultraviolet light and / or infrared light.

[0023] In particular, it may be provided that all light sources are located completely outside the sample chamber and / or spaced away from it. This prevents the sample from coming into contact with the light sources and from contaminating the light source or any window of the light source. The sample typically remains entirely within the sample chamber.

[0024] It should be understood that an arrangement outside the sample chamber typically means that the respective component or measuring device is located entirely outside of any volume designated for the sample. The respective component or measuring device is therefore not located within a closed subvolume surrounded by the volume designated for the sample.

[0025] The measuring device may be designed to include one or more optical fibers, each optically coupled to one or more light sources, directing light from these light sources onto the sample chamber. This allows the light sources to be spatially decoupled from the sample chamber, meaning, in particular, that they can be arranged at a greater distance and / or flexibly. An optical fiber can then transport the light to the desired location.

[0026] According to one embodiment, at least one measuring device may have a detector, which may be specifically designed to detect light emanating from the sample chamber and / or to measure the quantity based on this light. This allows optical measurements to be performed. The light emanating from the sample chamber may, for example, originate from the light beam mentioned above, which may be generated by the aforementioned light source. The light emanating from the sample chamber may be transmitted, scattered, and / or reflected light from the sample.

[0027] Accordingly, one or more detectors can be arranged. The light emerging from the sample chamber can also be light generated, for example, by fluorescence or a chemical reaction within the sample.

[0028] In particular, at least one detector can be configured to detect light emanating from a transparent area of ​​the sample chamber. Regarding the transparency of the sample chamber, please refer to the explanations already described above.

[0029] Each measuring device can, for example, have one light source, two light sources, or more than two light sources. Each measuring device can, for example, have one detector, two detectors, or more than two detectors. The descriptions provided herein apply to the light sources and detectors.

[0030] In particular, it may be possible for all detectors to be located entirely outside the sample chamber and / or at a distance from the sample chamber. As mentioned above with regard to light sources, this can prevent detector contamination.

[0031] The measuring device may in particular have one or more optical fibers, each of which is optically coupled to one or more detectors and in particular can direct light from the sample chamber to these detectors.

[0032] This allows the detectors to be spatially decoupled from the sample chamber, meaning they can be positioned at a greater distance and / or flexibly. Light can then be guided to the respective detectors via fiber optics.

[0033] It should be understood that the statements made herein with regard to measuring instruments, detectors, light sources, optical fibers, or other components are, in principle, applicable to any number of such components. If several such components are present, the statements may refer to only one such component, several such components, or all such components. It may also be intended that specific statements do not refer to any of the respective components.

[0034] In particular, at least one measuring device may be configured to measure light transmitted through and / or scattered within the sample. For measuring transmitted light, a detector of the measuring device may be positioned opposite a light source of the measuring device with respect to the sample chamber. This angle may correspond to 180°. For measuring scattered light, the detector may be positioned at a different angle, for example, 90°, 135°, or 45°. For instance, intervals of ±5° or ±10° around these values ​​may be defined within which measurements can be taken. A measuring beam may be used as a reference. Other angles are also possible. For measuring reflected light, which can also be described as scattered light, the detector may, for example, be positioned directly next to the light source.A measuring device can also be designed to measure light originating from a chemical reaction or fluorescence in the sample. Such a measurement is typically possible in all directions relative to the excitation light.

[0035] In particular, the sample chamber can have a completely continuous, flat surface on its interior for guiding the piston. The piston can be moved along this surface. Due to the completely flat design, the piston can remain in contact with the flat surface at all times, regardless of its position. As the piston moves along the flat surface, it can clean the surface, for example, by removing adhering particles of dirt. These particles then typically enter the sample and are ejected during the next ejection cycle. This eliminates the need for additional cleaning measures and allows for very simple cleaning of the sample chamber.

[0036] According to an advantageous embodiment, the measuring device includes a multi-port valve. This valve can, in particular, have several ports that can be selectively connected to the sample chamber. For example, it can have two, three, four, five, six, or more ports. This allows one port to be selectively connected to the sample chamber at a time, while in a given state the other ports are not connected to the sample chamber. This allows, for example, the targeted aspiration of a sample from one of several different sources, and / or the discharge of the sample to a specific sink, such as back into a fluid stream from which the sample was previously taken, or to a separate disposal device. This significantly increases the versatility of the measuring device.As an alternative to the design in which only one connection is always connected to the sample chamber, a multiple valve can also be designed in such a way that in a certain switching position several connections, for example two connections, are connected to the sample chamber.

[0037] The measuring device may, in particular, include a valve actuator for switching the multiple valve. Specifically, an electric motor, an electromagnet, a pneumatically or hydraulically driven cylinder, and / or a pneumatic or hydraulic motor may be used for this purpose. A manually operated valve actuator, i.e., one operated by human muscle power, is also possible.

[0038] According to one embodiment, at least one port of the multi-valve is connected to ambient air and / or to an air reservoir for drawing air into the sample chamber. This allows air to be selectively drawn into the sample chamber by selecting this port on the multi-valve, which can be useful, for example, for calibrating a measuring instrument.

[0039] to carry out. In particular, the multi-valve and / or the valve actuator can be arranged at a longitudinal end of the sample chamber opposite the actuator. This allows for a compact and practical design, whereby the piston is actuated at one longitudinal end of the sample chamber, and selective fluid supply and discharge is possible at the other longitudinal end of the sample chamber.

[0040] One, some, or all of the ports of the multi-port valve can be positioned transversely to a direction of piston movement and / or transversely to a longitudinal extent of the sample chamber. This allows for good accessibility. Instead of a transverse orientation, an orientation at an angle of no more than 10°, no more than 25°, or no more than 45° can also be provided.

[0041] The sample chamber may, in particular, be equipped with a secondary connection for supplying and / or discharging fluid. Such a secondary connection can be designed as an opening in the sample chamber. Connection elements may also be present. It may also be provided that the sample chamber has a first secondary connection for supplying and / or discharging fluid, as well as a second secondary connection for supplying and / or discharging fluid. This allows fluid to flow through the sample chamber, which can be introduced and discharged via the secondary connections.

[0042] In particular, the first and second secondary ports may be arranged at opposite longitudinal ends of the sample chamber. This can allow for complete fluid flow through the sample chamber.

[0043] The piston can be configured to close at least one auxiliary port in one position and open it in another. In particular, it can be provided that the piston closes an auxiliary port in one end position and preferably opens the auxiliary port outside of this end position. This allows for simple valve functionality. It can be implemented for one auxiliary port, several auxiliary ports, or all auxiliary ports.

[0044] Auxiliary ports are defined as ports that are present in addition to a primary port, which primarily serves the normal function of filling and emptying the sample chamber by moving the piston. Auxiliary ports thus allow for the expansion of functionality. The primary port can, for example, be referred to as the main port. It can be, for instance, a connector. This connector can, for example, establish a fluidic and / or mechanical connection to a valve, such as a multi-port valve. The main port and / or the connector can be located, in particular, on the end face of the sample chamber.

[0045] The piston and / or piston rod may be equipped with an auxiliary port for supplying and / or discharging fluid. This allows a fluid flow to be supplied or discharged through the piston and / or piston rod. The piston's auxiliary port can, for example, be connected with a flexible hose. This preserves the piston's mobility. The auxiliary port can be located, in particular, at a longitudinal end of the piston or piston rod, especially at a longitudinal end opposite the sample chamber. The piston and / or piston rod can be hollow internally. This allows fluid exchange between the piston's auxiliary port or piston rod and the sample chamber.

[0046] A piston rod can, in particular, connect the piston to the drive mechanism. It can, in particular, be an elongated element.

[0047] The sample chamber may be equipped with one or more measuring electrodes for performing electrical measurements on the fluid contained within it. This allows, for example, conductivity measurements of the sample. In particular, two or four measuring electrodes may be arranged in the sample chamber. The measuring electrodes may be applied to an inner surface of the sample chamber, for example, as an internal coating. They may be traversed by the piston, thus enabling cleaning.

[0048] According to an advantageous embodiment, the measuring device has at least one reservoir for a reagent. Typically, each reservoir is connected to a port of the multi-port valve for drawing the reagent into the sample chamber. One reservoir can be used, or several reservoirs can be used. This allows reagents to be kept ready for drawing into the sample chamber as needed.

[0049] For example, such a reagent can be used to calibrate a measuring instrument. A reagent can also be mixed with a sample to trigger a specific chemical reaction. Mixing a reagent with a sample can be achieved, for example, by alternately filling the sample chamber with the sample and the reagent. The reagent can also be used, for example, to color or otherwise condition the sample. For instance, when the piston is moved in the first direction, a sample can be drawn in first, followed by a reagent. The multi-port valve can be actuated in between to connect the respective port to the sample chamber. A reverse sequence or alternating aspiration is also possible.

[0050] In particular, the piston can form a sealing contact with an inner surface of the sample chamber. This allows the piston to divide the sample chamber into two compartments, typically containing the sample in one compartment and empty in the other, which could, for example, contain air. This sealing contact advantageously achieves the desired functionality of the piston for drawing in and ejecting the sample. Furthermore, the sealing contact also generates a degree of friction when the piston moves within the sample chamber, thus providing a cleaning effect on the inner surface. This eliminates the need for additional cleaning measures, such as the use of special wipers or the removal of components for external cleaning.In particular, the piston can have an external seal. This seal can, in particular, rest against the inside of the sample chamber. The seal can be made of, for example, rubber, plastic, or another material, especially a flexible one. The seal advantageously seals the aforementioned areas against each other. It can also contribute to the cleaning effect.

[0051] In particular, the piston can be designed for internal cleaning of the sample chamber. This can specifically mean that, during its movement within the sample chamber, the piston mechanically interacts with the sample chamber and thereby cleans the sample chamber, especially an inner surface of the sample chamber.

[0052] In particular, the first direction can be opposite to the second direction. The piston can be designed to be linearly movable within the sample chamber. In particular, the piston can be designed to be exclusively linearly movable and / or one-dimensionally movable within the sample chamber.

[0053] The drive unit can be designed, in particular, as an electric motor with a rotary-translation gearbox. This allows for easy actuation of the piston. Instead of an electric motor, a hydraulic or pneumatic drive unit can be used, for example. A piston rod can be provided between the drive unit and the piston.

[0054] According to an advantageous embodiment, the sample chamber has a completely or at least partially constant internal cross-section along its longitudinal extent. This can, in particular, improve the piston's performance and / or enhance or enable its cleaning effect.

[0055] In particular, the sample chamber can have a completely or at least partially round or oval internal cross-section and / or external cross-section.

[0056] In particular, the sample chamber can have a rectangular or square internal and / or external cross-section, either completely or at least partially. Such cross-sections are easy to manufacture and have proven advantageous for the design described here. The sample chamber can, in particular, be cylindrical. This allows, in particular, the use of easily manufactured cylindrical components.

[0057] In particular, the sample chamber can be at least partially, or even completely, optically transparent. This can refer to visible light, ultraviolet light, and / or infrared light. This allows for advantageous optical measurements. Associated measuring instruments, including their light sources and detectors, can be located outside the sample chamber.

[0058] In particular, the measuring device can be designed to analyze a liquid sample, especially water, and / or to analyze a gas. This allows the analysis of such samples, which are frequently required in drinking water supply systems or in chemical process engineering, for example, to ensure quality for delivery to customers or for use in a chemical process.

[0059] The invention further relates to a fluid supply system. The fluid supply system includes, in particular, a fluid line. The fluid supply system includes, in particular, a dispensing device for dispensing fluid from the line. The fluid supply system includes, in particular, a measuring device, which may be designed as described herein. With regard to the measuring device, all embodiments and variants described herein may be used. The dispensing device is designed, in particular, to dispense fluid from the line or from a sample container and supply it to the measuring device for analysis.

[0060] A fluid supply system of this type allows fluid to be delivered to a consumer. For example, it can be fed into a public pipeline network, or it can supply fluid for a chemical process. The pipeline typically carries a main flow of fluid. This flow typically leads from a source to a consumer or a distribution network. The sampling device typically extracts only a small quantity of the fluid, which is then used as a sample in the measuring device and, in particular, analyzed therein. A sampling device can be designed, in particular, as a sampling line, which can be connected to the pipeline.

[0061] The fluid supply system can be configured as a liquid supply system, a water supply system, and / or a gas supply system. A liquid supply system supplies another unit with a liquid. A gas supply system supplies another unit with a gas. A water supply system is defined in particular as a system that supplies consumers or customers with water, especially drinking water. This can include, for example, typical units of a public drinking water supply system.

[0062] In particular, the fluid supply system may include one or more filter systems. It may be provided that a sampling device is arranged upstream and / or downstream of one, some, or all of the filter systems. This sampling device may be connected to a connection of a multi-port valve of the measuring device. Reference is made to the description of the multi-port valve given above. This allows, for example, the monitoring of the filter's effectiveness. A filter system is specifically designed to filter out unwanted components, such as particles, from the fluid. For this purpose, sieves, nets, porous materials, settling tanks, or other devices may be used.

[0063] If sampling points are located both upstream and downstream of the filter system, the effectiveness of the filter system can be easily verified. This can be done using just one measuring device, which, as mentioned, can be connected to both sampling points. Alternatively, several measuring devices, for example two, can be used.

[0064] The invention further relates to a method for analyzing a sample. For this purpose, a measuring device as described herein can be used in particular. With regard to the measuring device, all embodiments and variants described herein can be used. Preferably, the method comprises the following steps:

[0065] The sample is drawn into the sample chamber by moving the piston in the first direction, then

[0066] Perform at least one measurement using at least one measuring device on the sample located in the sample chamber, and then

[0067] Pushing the sample out of the sample chamber by moving the piston in the second direction.

[0068] Using such a method, a sample can be advantageously analyzed. Typically, the piston is moved in each direction until it reaches a stop or end position. Reference is made to the explanations already given above.

[0069] The procedure may, in particular, further include the following step:

[0070] Perform at least one reference measurement using at least one measuring device without a sample in the sample chamber.

[0071] This allows a measuring device to be easily calibrated or otherwise referenced. If there is no sample in the sample chamber, the measuring device typically only measures the conditions of the sample chamber and, if applicable, other components, but without the sample itself.

[0072] For example, the aging of a light source or changes in the sensitivity of an optical detector can be measured. This allows interference from a separate, subsequent measurement with a probe to be compensated for. For example, signals can be subtracted from each other or otherwise processed to account for the reference.

[0073] According to an advantageous embodiment, the method may further comprise the following steps:

[0074] Moving the piston in the first direction without drawing in a sample and while drawing in air, or while drawing in a reference gas, or while drawing in a reference liquid, then

[0075] Perform at least one reference measurement using at least one measuring device without a sample in the sample chamber, and then move the piston in the second direction.

[0076] Using this procedure, the sample chamber can be deliberately used without a sample to perform a reference measurement. In a given application, it is typically known what constitutes a sample and what does not. For example, if the procedure is carried out within the context of a drinking water supply, a sample is generally drinking water taken from a facility supplying a public network or other consumers. Air is typically ambient air. A reference gas can be, for example, a specific type of gas, such as nitrogen or a noble gas like neon or argon, or it can be a gas mixture used as the reference gas. A reference liquid can be taken, in particular, from a designated container.This could be, for example, ultrapure water, deionized water, tap water, a mixture of certain liquid substances, or another pure substance. The reference measurement can be performed according to the steps to be carried out on the respective measuring instrument, just like a measurement to determine a parameter of the sample. The acquired data can be saved and used as a reference in future sample analysis or in the analysis of previously performed measurements. For example, the respective measurement data can be subtracted from each other. However, it is also possible that a reference measurement is performed differently than a measurement to determine a measurand of the sample, for example, that a reference measurement is longer or shorter, uses different wavelengths, or has different intensities.Typically, standard measurements to determine a measurand of the sample are carried out before and after a reference measurement, i.e., in particular with the sample located in the sample chamber.

[0077] A reference measurement can be used, in particular, for calibrating and / or verifying the measuring instrument. It can also be performed between every two measurements, so that, for example, a measurement to determine a parameter of the sample, with the sample in the sample chamber, is always performed alternately with a reference measurement. The next measurement is then typically another measurement to determine a parameter of the sample.

[0078] In particular, the reference measurement can be performed with the sample chamber filled with air or with a reference gas or reference liquid. Reference is made to the explanations already given above. This allows a defined condition for a reference measurement to be established. Air, reference gas, and / or reference liquid can be drawn in by moving the piston in the first direction and expelled by moving the piston in the second direction.

[0079] The reference gas can be, in particular, an inert gas, nitrogen, a noble gas, helium, neon, argon, and / or krypton. Mixtures of these, as well as mixtures with other substances, or the use of other substances altogether, are also possible. The reference liquid can be, in particular, ultrapure water, distilled water, drinking water, and / or deionized water. Mixtures of these, as well as mixtures with other substances, or the use of other substances altogether, are also possible.

[0080] The procedure may also include the following steps:

[0081] Aspirating a cleaning fluid into the sample chamber by moving the piston in the first direction, and then

[0082] The cleaning fluid is forced out of the sample chamber by moving the piston in the second direction.

[0083] A cleaning fluid is particularly suitable for absorbing dirt or other foreign matter present in the sample chamber and thereby removing it from the chamber when the piston is moved in the second direction. The cleaning fluid can be, for example, ultrapure water, tap water, or deionized water. However, it can also be a fluid containing cleaning components such as soap, detergent, surfactants, chlorine solution, alcohol, or other cleaning substances. This allows for an additional cleaning effect from the cleaning fluid, supplementing the normal cleaning action of the piston itself. In particular, multiple measurements on the sample in the sample chamber can be performed sequentially using separate measuring instruments. This means, specifically, that the measuring instruments are used one after the other.In particular, this can mean that a measurement is performed with one measuring device while all other measuring devices are not in use, then a second measuring device is used while all other measuring devices are not in use, and, if necessary, further measuring devices are used exclusively. Specifically, performing multiple measurements sequentially can mean that the measurements are carried out one after the other in such a way that only one measuring device is used at any given time, or that at most one light source is active at any given time. This reduces mutual interference between measurements. Even with a measuring device that is designed, for example, to perform two different measurements, these can be carried out sequentially. The same applies if the measuring device is designed to perform more than two different measurements.

[0084] However, it is also generally possible to perform measurements simultaneously, especially if they do not influence each other. Simultaneous execution can also be referred to as parallel execution.

[0085] Sequential and parallel execution can also be combined.

[0086] The detectors can be, for example, a photodiode, a photomultiplier, a charge-coupled device (CCD), and / or a CMOS sensor. The detectors can, for example, measure incident light in an integrated manner, they can be divided into multiple sectors or pixels, and / or they can be designed for wavelength-selective measurement. A device designed for wavelength-selective measurement can also be called a spectrometer. A light source can also be a laser.

[0087] In particular, light absorption or attenuation of radiation can be determined by optical measurement. This allows for the calculation of an attenuation coefficient (AC) or a spectral absorption coefficient (SAC). For example, wavelengths from 200 nm to 800 nm (UC / VIS wavelength range) can be used. Analyses in the range of 200 nm to 350 nm are typically referred to as UV (ultraviolet) photometry. Above 350 nm, the term VIS (visible light) photometry is typically used. For example, the measuring instruments can be configured to measure one or more of the following parameters:

[0088] spectral absorption coefficient (for example at 254 nm),

[0089] UV transmission (for example at 254 nm),

[0090] biochemical oxygen demand (BOD),

[0091] Chemical oxygen demand (COD),

[0092] total organic carbon (TOC),

[0093] dissolved organic carbon (DOC),

[0094] Total solids content (TSS),

[0095] Total nitrogen (TNb),

[0096] Nitrate (NO3),

[0097] Nitrite (NO2),

[0098] Color,

[0099] Cloudiness

[0100] Ammonium (NH4),

[0101] Orthophosphate.

[0102] Turbidity can be measured, for example, according to standard ISO 7027. An LED light source with a wavelength of 860 nm and a spectral bandwidth of ± 30 nm can be used for this purpose. The measurement setup can be configured with a detector angle of 90° to the light source (primary measurement) and a secondary measurement at 180°. Possible parameters and units include, for example, formazin attenuation units (FAU), formazin nephelometry units (FNU), formazin turbidity units (FTU), or nephelometric turbidity units (NTU).

[0103] Particles can be measured, for example, in a measurement range of 0.5 to 30 pm or larger. A laser light source with a wavelength of 488 nm can be used for this purpose. A photodiode and / or a silicon photomultiplier can be used as detectors. A measurement setup can be designed, for example, to measure light scattered at 90° as well as forward-scattered light. Possible parameters include particle size, particle shape, and particle surface structure.

[0104] Photometric measurement methods can determine parameters such as color, absorption, transmission, concentration, turbidity, or particles. Spectral measurements, for example, allow the measurement of potential dissolved organic substances in water using the light spectrum in the wavelength range from ultraviolet to visible light, as well as standardized wavelengths such as 254 nm, 436 nm, 525 nm, or 620 nm.

[0105] In the embodiment described herein, the analyzed sample is transported into a body such as the aforementioned sample chamber. This chamber is preferably transparent or at least has transparent areas. These transparent areas typically possess sufficient optical quality to allow light to enter the sample and to receive light using optical sensors, particularly without the need for light sources or detectors within the sample chamber.

[0106] An optical-fluidic measuring device typically includes a measuring cuvette, a measuring cylinder, and a plunger for drawing up and ejecting the sample. Light sources and detectors, spectrometers, and optical light receivers can be arranged at any angle to each other and to the measuring cuvette. Samples can be introduced via a tube or pipe, for example, directly or via a (multi-port) valve through a device carrying other sample media, or simply by immersing the measuring cuvette in the sample liquid. Optionally, a multi-port valve, which may have eight ports or another number of ports, can be used to transport different media or samples into the measuring cell or sample chamber.

[0107] With each ejection of the liquid being measured, the plunger or piston in the measuring cylinder cleans the surface of the sample chamber. This ensures identical optical conditions for every subsequent measurement. In principle, precise recalibration can be performed after each measurement. Should contamination occur after a certain operating period, despite cleaning the optical surfaces with each measurement, cleaning fluid can be drawn in to automatically clean the sample chamber. The measuring cuvette or sample chamber can be designed in any geometric shape, such as square, oval, round, or rectangular. To prevent interference with the respective sensor planes or measuring channels, the individual measured variables can optionally be acquired sequentially.

[0108] The measurement principle for all optically measured parameters is preferably photometric and / or colorimetric. The sample should be transported, for example, into a cuvette, in particular an optically transparent cuvette, such as a quartz glass cuvette or sample chamber with an optically usable length of, for example, approximately 50 mm. The measuring sections for the optical measurement of different parameters should be modular, regardless of whether the measurement is taken with transmitted light or laterally at a certain angle (e.g., 90°, 135°, or 45°). Temperature differences between the environment and the sample can cause water vapor condensation on the outer wall of the measuring cuvette and thus impair the optical measurement.

[0109] All light sources can, for example, have an identical design. However, they can also have different designs. The light sources can be LEDs and / or lasers. Adjustable temperature stabilization can be provided, for example, by a Peltier element. The optical detectors can differ only in their optical filters. The detectors can be photodiodes or silicon photomultipliers, for example. Current and voltage converters and / or signal amplifiers, and / or ADCs can be temperature-compensated.

[0110] Optical filters, such as bandpass filters, can be used in front of the detectors. The measuring sections can be arranged circularly around the measuring cuvette and along the cuvette over a length of approximately 50 mm.

[0111] Cleaning the inside of the measuring cuvette is inherent to the system, for example, as the sample is drawn into and ejected from the cuvette by a plunger. If potential condensation of humidity on the outside of the cuvette can be prevented, cleaning the outside of the measuring cuvette is only necessary, for example, during annual instrument servicing.

[0112] Periodic calibration of optical parameter values ​​can be fully automated, for example by drawing standard calibration fluids into the cuvette.

[0113] Since the optical module typically only contains one cuvette, only one sample layer thickness is measured. To ensure measurements are as close to standards as possible, the measuring path can be adjusted: For example, the measuring beam is deflected so that it passes through the sample multiple times at different points. This can be achieved, for instance, by incorporating mirrors and / or reflective surfaces in the sample chamber.

[0114] For example, an optical oxygen sensor can be arranged in the measuring chamber to measure oxygen levels. This sensor can have a membrane with a fluorescent dye.

[0115] For example, a pH electrode can be arranged in the measuring chamber to measure the pH value.

[0116] With additional connections as described herein, it is possible to measure parameters either discontinuously, for example every 5 to 10 minutes (Near Real Time), or continuously (Real Time).

[0117] The terms measuring chamber and sample chamber can be used synonymously.

[0118] Electrical conductivity (e.g., in pS / cm) and / or TDS value (Total Dissolved Solids, e.g., in ppm) are important and frequently used analytical parameters that provide information about water quality. Pure water is inherently non-conductive and therefore does not conduct electricity. Only dissolved substances in the water, such as chlorides, sulfates, or carbonates, make it conductive. Measuring this conductivity allows conclusions to be drawn about the amount of dissolved particles in the water. The more dissolved particles are, the higher the water's conductivity.

[0119] Measurement is performed, for example, by applying an electrical voltage to the sample. The resulting electric current depends on the electrical conductivity of the sample. Depending on the method or application, the measuring device either keeps the voltage signal constant and registers the change in electric current, or it keeps the current value constant and evaluates the voltage change.

[0120] A 2-pole measuring arrangement, for example, has two electrodes between which a constant alternating voltage is applied. The current flowing through the measuring solution is the measurement signal.

[0121] A 4-pole measuring arrangement has, for example, two pairs of electrodes. One pair measures the current flowing through the sample solution, the second pair of electrodes measures the voltage applied across the sample solution.

[0122] A device for measuring the conductivity and / or TDS value directly in the measuring cuvette is described herein.

[0123] The electrodes required for this can be applied to the measuring cuvette or sample chamber using thin-film technology, for example, by physical vapor deposition (PVD). These measuring electrodes can be made of gold or platinum, for example, and their layer thickness typically measures a few nanometers to micrometers. The shape, number, and arrangement of these electrodes can be adapted to the physical properties of the medium being measured.

[0124] An alternative solution to integrating the measuring electrodes into the cuvette is to place the electrodes in the bottom of the measuring cylinder.

[0125] Electrical conductivity measurement can be performed with two, four, or more electrodes. Attaching these measuring electrodes to the cuvette offers the following new possibilities and advantages:

[0126] An additional conductivity sensor, which would have to be elaborately integrated into the measuring arrangement, is no longer necessary.

[0127] The piston, which is used to transport the sample in the measuring cuvette, simultaneously cleans the surface of the metallic measuring electrodes. This eliminates the need for periodic, manual cleaning.

[0128] Attaching the measuring electrodes to the inner surfaces of the measuring cylinder allows for many variations in number, geometric design and positioning.

[0129] Integration into the measuring cylinder results in a compact and space-saving solution.

[0130] Since no additional components are required and the physical vapor deposition (PVD) process is also well suited for large batch sizes, costs are reduced.

[0131] Continuous measurement ensures that certain events are not missed. For example, the option to allow the sample to flow through the measuring cuvette enables the continuous measurement of the following parameters:

[0132] Turbidity

[0133] SAK 254

[0134] Conductivity, TDS

[0135] temperature

[0136] PH value

[0137] The device described herein allows the sample to flow through the measuring cuvette or sample chamber either discontinuously or continuously. A lateral bore at the upper end of the measuring cuvette wall and the attachment of a hose connector enable the continuous flow of the sample from bottom to top when the piston is located above this bore. As the piston moves downwards within the cuvette, the flow is interrupted as soon as the piston is below the outlet bore. The sample can be introduced from below, for example, through the multi-way valve, or, analogous to the above design, a bore and hose connector can also be attached to the lower end of the cuvette. Continuous flow could also be achieved through the piston by equipping it with a through-hole and hose connector.

[0138] This fluidic arrangement enables, for example, combined discontinuous / continuous measurement in a cuvette by drawing the sample up and ejecting it with the piston, or by allowing it to flow through the cuvette when the piston is in its uppermost position. With a lateral bore at the top of the cuvette wall and the attachment of a hose connector, no additional valve is required, as the piston performs this function. However, a secondary connection, for example, can also be controlled by a separate valve.

[0139] Further features and advantages will be apparent to those skilled in the art from the exemplary embodiments described below with reference to the accompanying drawing. Figure 1 shows a fluid supply system.

[0140] Figs. 2 to 9: a measuring device of the fluid supply system in different views and states,

[0141] Figs. 10 to 13: a sample chamber with further components of the measuring device, Figs. 14 to 17: a sample chamber with further components according to an alternative embodiment,

[0142] Figs. 18 to 21: a sample chamber with further components according to a further alternative embodiment,

[0143] Figs. 22 to 24: a sample chamber with further components according to a further alternative embodiment,

[0144] Figs. 25 to 27: a sample chamber with further components according to a further alternative embodiment,

[0145] Figs. 28 to 30: a sample chamber with further components according to a further alternative embodiment,

[0146] Figs. 31 to 33: a sample chamber with further components according to a further alternative embodiment, and

[0147] Figures 34 to 42: Sample chambers according to further embodiments. Figure 1 shows a purely schematic representation of a fluid supply system 10 according to one embodiment. The fluid supply system 10 can, for example, be a water supply system and thus serve to supply water, for example, drinking water. The fluid supply system 10 has a line 20 for fluid. This is a line that carries the fluid, such as drinking water. The line 20 can, for example, connect a device for treating extracted drinking water to a public drinking water supply network. In this case, a filter system 30 is located in the line 20, in which the flowing fluid is filtered. The direction of flow is indicated by an arrow.

[0148] A measuring device 100, as described in one embodiment, is used to monitor the fluid flowing through line 20. The measuring device 100 has a sample chamber 110. Fluid to be analyzed can be introduced into the sample chamber 110, as will be described in more detail below. It has optically transparent areas 112. A piston 120 is located inside the sample chamber 110. The piston 120 seals against an inner surface of the sample chamber 110. The piston 120 is connected to a piston rod 122. This rod is used to move the piston 120 within the sample chamber 110. The piston rod 122 is, in turn, connected to a drive unit 125 in the form of an electric motor with a rotary-translation gearbox. This allows the drive unit 125 to move the piston rod 122 in one dimension, i.e., linearly, and thus also to move the piston 120 within the sample chamber 110.This allows the piston 120 to be moved, in particular, in a first direction, which, in the embodiment shown in Fig. 1, points upwards, to draw fluid into the sample chamber 110. The piston 120 can also be moved in a second direction opposite to the first, which, in the illustration of Fig. 1, points downwards. This allows fluid to be expelled from the sample chamber 110. Since the piston 120 seals against the inner surface of the sample chamber 110 on its outer side, not only can the pressure required for the described processes be built up in the sample chamber 110, but the piston 120 also simultaneously performs a cleaning function for the inner surface of the sample chamber 110 through mechanical friction. Additional special cleaning devices can therefore be advantageously dispensed with. The sample chamber 110 is projected from a base body 105 of the measuring device 100.The base body 105 holds the sample chamber 110 and also serves to attach further components, which are described below.

[0149] The measuring device 100 includes a multi-port valve 130. The multi-port valve 130 has several ports 132, which can be connected to components external to the measuring device 100. The measuring device 100 also includes a valve actuator 135 in the form of an electric motor, which serves to drive the multi-port valve 130. Depending on its position, the multi-port valve 130 connects only one of the ports 132 to the interior of the sample chamber 110 at any given time. Thus, it is possible to select which of the ports 132 should be connected to the sample chamber 110. This allows for the targeted aspiration of fluid from a specific source and / or the discharge of fluid to a specific sink.

[0150] In this case, a connection 132 is connected to a first sampling device 21 in the form of a pipe, which is connected to line 20 upstream of the filter system 30 in the direction of flow. A further connection 132 is connected to a second sampling device 22 in the form of a pipe, which is connected to line 20 downstream of the filter system 30 in the direction of flow. This allows fluid to be drawn in both upstream and downstream of the filter system 30. The effectiveness of the filter system 30 can thus be monitored, for example, by first taking a measurement with fluid that was taken upstream of the filter system 30 and immediately afterwards taking a measurement with fluid that was taken downstream of the filter system 30.This allows, for example, verification that the filter system 30 removes particles or other components from the fluid as desired, or, if necessary, releases additional particles into the fluid in the event of a malfunction.

[0151] The measuring device 100 comprises two measuring instruments, namely a first measuring instrument 210 and a second measuring instrument 220. In principle, the measuring device 100 could also have more or fewer measuring instruments. The first measuring instrument 210 is attached to a first bracket 141. The second measuring instrument 220 is attached to a second bracket 142. The two brackets 141 and 142 are detachably attached to the base body 105. They are also detachably connected to each other. This allows for a modular assembly of the measuring device 100, whereby the measuring instruments 210 and 220 can be removed by removing their respective brackets 141 and 142 and, for example, replaced by other measuring instruments. Similarly, a measuring instrument 210 or 220 can be easily removed for maintenance purposes in this way. The exact design will be discussed in more detail below.

[0152] Only some of the components of measuring instruments 210 and 220 are shown in Fig. 1. The representation is schematic and does not reflect the actual spatial arrangement of the components, which is shown and described below in Figs. 2 to 9. The first measuring instrument 210 consists of a light source 212 and a detector 214. The second measuring instrument 220 also consists of a light source 222 and a detector 224. Further components of measuring instruments 210 and 220 will be described below with reference to Figs. 2 to 9.

[0153] The measuring device 100 also includes a reservoir 150. The reservoir 150 is suitable for holding a reagent. As shown, the reservoir 150 is connected to one of the ports 132 of the multi-port valve 130. This allows the reagent contained in the reservoir 150 to be drawn into the sample chamber 110 when the multi-port valve 130 is in the appropriate switching position. This allows, for example, the fluid from line 20 to be mixed with the reagent in order to trigger a chemical reaction within the sample chamber 110. This enables measurements to be carried out, for example, to check the extent to which the sample has reacted with the reagent or which particles have been formed.

[0154] Fig. 2 shows the measuring device 100 separately without the reservoir 150 and without the drive device 125.

[0155] It can be seen that the brackets 141 and 142 are ring-shaped. They are stacked on top of each other, a point which will be discussed in more detail below. As shown, the first bracket 141 has several positions to which components of the first measuring device 210 can be attached.

[0156] Accordingly, the second bracket 142 has several positions at which components of the second measuring device 220 can be attached. The positions are each arranged such that they are angularly spaced 90° apart from their adjacent positions.

[0157] In the first measuring device 210, the light source 212 is arranged in one position, and the previously mentioned detector 214 is arranged in a position offset by 90° to it. Directly in line with the light source 212, i.e., at an angular distance of 180°, a shutter 144 is attached, which closes one position of the first support 141 and thus prevents unwanted light from entering or exiting. The configuration shown, with the detector 214 positioned at 90° to the light source 212, is particularly useful for measuring the turbidity of a sample in the sample chamber 110, with the detector 214 specifically measuring light scattered within the sample.

[0158] In the second measuring device 220, a detector 224 is arranged at an angular offset of 90° relative to the light source 222, and another detector 226 is arranged directly opposite it, i.e., at an angular offset of 180°. Thus, both transmission and scattering can be measured in the second measuring device 220. The detectors 214, 224, and 226 can each be configured, for example, to measure the intensity of the total incoming light; however, they can also measure the intensity in a wavelength-selective manner, and / or they can be divided into pixels to capture a spatial distribution of the incoming light, optionally combined with wavelength-selective measurement. This allows measurements to be performed on a sample in the sample chamber 110.

[0159] The upper sides of the brackets 141, 142 are covered by a cover 145, which covers the area between the circumference of the second bracket 142 and the sample chamber 110. This prevents unwanted light from entering at the point shown at the top in Fig. 2 and interfering with the measurement by the measuring instruments 210, 220.

[0160] Fig. 3 shows the measuring device 100 from a different view. It can be seen that the first measuring device 210, in addition to the detector 214 already mentioned, also has a further detector 216, which is also arranged at an angular offset of 90° to the light source 212 and opposite to the detector 214. Scattered light can thus be measured from both sides. Furthermore, it can be seen that the second measuring device 220 has a further light source 223, which is arranged at an angular offset of 90° to the light source 222 and opposite to the detector 224 already mentioned, i.e., at an angular offset of 180° to it. Both detectors 224 and 226 can therefore both be used to measure transmitted as well as scattered light.

[0161] Fig. 4 shows the measuring device 100 from a different view. Fig. 5 shows the measuring device 100 from a perspective view at an angle from above.

[0162] Fig. 6 shows the measuring device 100 in an exploded view, with the two supports 141, 142 no longer fixedly connected to the rest of the measuring device 100. The cover 145 is also no longer fixedly connected to the rest of the measuring device 100. These components can, in principle, be removed and, for example, replaced or otherwise modified, in particular including the measuring instruments 210, 220.

[0163] A mounting device 160 is formed on the base body 105, to which each of the holders 141, 142 can be attached. An identical mounting device 160 is formed on each of the holders 141, 142, so that the holders 141, 142 can also be attached to each other in the same way as they can be attached to the base body 105. The cover 145 can also be attached to a mounting device 160 in a corresponding manner. This allows for maximum modularity of the system. The mounting devices 160 are described below with reference to Fig. 7, which shows a perspective view. Each of the mounting devices has a support surface 162. This surface is oriented transversely to a longitudinal dimension of the sample chamber 110. A holder 141, 142 can be placed flush on this surface, particularly when it is slid onto the holder along the longitudinal dimension of the sample chamber 110.Cover 145 can also be installed.

[0164] Each of the fastening devices 160 further comprises a circumferential projection 164. This projection is annular and serves to radially stabilize the respective mounting bracket 141, 142 in all directions. The circumferential projection 164 is located, in particular, radially on the inside of the mounting bracket 141, 142. The same applies to the mounting cover 145 and its radially circumferential wall.

[0165] The described design of the fastening devices 160 thus serves to easily assemble the measuring device 100 with interchangeable and easily removable brackets 141, 142, to which respective measuring devices 210, 220 are attached.

[0166] Fig. 8 shows an exploded view of the measuring device 100, with the brackets 141, 142 visible from the other side. It can also be seen that the brackets 141, 142 each have receiving spaces 147 into which the projection 164 of a fastening device 160 can engage.

[0167] Fig. 9 also shows an exploded view, but in a side view. Furthermore, in the view of Fig. 9, components such as the light sources 212, 222, the detectors 214, 224, 226 and the shutter 144 are removed from the supports 141, 142.

[0168] Figures 10 to 13 show the sample chamber 110 and the piston rod 122, specifically in the embodiment used in the exemplary embodiment of the measuring device 100 described with reference to Figures 2 to 9. The sample chamber 110 has a circular cross-section. Along its circumference, there are a total of four transparent areas 112 in which the sample chamber 110 is optically transparent. This allows a light beam from one of the light sources 212, 222, 223 to enter and light to exit the sample chamber 110 to the detectors 214, 224, 226. On its underside, i.e., opposite the piston rod 122, the sample chamber 110 has a connector 115 with an external thread for connection to the base body 105. The sample chamber 110 can therefore be screwed into the base body 105 and can, in principle, also be removed from it by turning it in the opposite direction.Within the connector 115 there is a passage or main connection, so that a fluidic connection is formed with the multiple valve 130 and the connections 132 of the multiple valve can be selectively connected to the sample chamber 110.

[0169] Between the transparent areas 112, the sample chamber 110 is not transparent on the outside.

[0170] Figures 14 to 17 show a sample chamber 110 according to an alternative embodiment. In contrast to the embodiment described so far, the sample chamber 110 has no transparent areas but is made entirely of transparent material. Light can therefore enter and exit everywhere. As shown, the sample chamber 110 has a rectangular cross-section.

[0171] Figures 18 to 21 show a sample chamber 110 according to a further embodiment. In contrast to the embodiment shown in Figures 14 to 17, the cross-section is not rectangular, but square. In this case as well, the sample chamber 110 is made entirely of a transparent material.

[0172] In principle, it is also possible in the embodiments shown in Figures 14 to 21 for the sample chamber 110 to be only partially transparent, as described with reference to Figures 10 to 13. The same applies to the embodiments described below.

[0173] Figures 22 to 24 show a sample chamber 110 according to a further embodiment. A first auxiliary port 116 and a second auxiliary port 117 are provided at the longitudinal ends of the sample chamber 110. These allow a fluid flow to pass through the sample chamber 110. For example, the first auxiliary port 116 can serve as an inlet and the second auxiliary port 117 as an outlet, or vice versa.

[0174] Figures 25 to 27 show a sample chamber 110 according to a further embodiment. In this embodiment, a secondary connection 117 is provided at one of the longitudinal ends of the sample chamber 110. This can be used for filling or emptying the sample chamber 110. No other secondary connection is provided in this embodiment. When the piston 120 is in its uppermost position, it automatically opens the secondary connection 117; otherwise, it closes the first secondary connection 117. This functionality can also be implemented in other embodiments. It could also be implemented in reverse.

[0175] Figures 28 to 30 show a sample chamber 110 according to a further embodiment. In this embodiment, a secondary connection 118 is formed on the upper side of the piston rod 122. This allows fluidic access to the sample chamber 110 via the piston rod 122 and the piston 120. These are preferably hollow on the inside for this purpose.

[0176] Figures 31 to 33 show a sample chamber 110 according to a further embodiment. In this embodiment, an auxiliary port 118 is formed on the upper side of the piston rod 122. This allows fluidic access to the sample chamber 110 via the piston rod 122 and the piston 120. These are preferably hollow on the inside for this purpose. Additionally, an auxiliary port 116 is formed at the opposite longitudinal end of the sample chamber 110. This allows, for example, the provision of a fluid flow through the two auxiliary ports 116 and 118.

[0177] Figures 34 to 42 show sample chambers 110 according to further embodiments. Measuring electrodes 170 are provided in the sample chamber 110.

[0178] In the embodiments shown in Figures 34 to 38, one or two measuring electrodes 170 are attached to one longitudinal end of the sample chamber 110, as shown. In the embodiment shown in Figures 34 and 35, these are rectangular; in the embodiment shown in Figure 36, they are round; and in the embodiment shown in Figures 37 and 38, they are oval. The measuring electrodes 170 are in each case mounted flat on the inside of the sample chamber 110.

[0179] Figures 39 and 40 show an embodiment in which the sample chamber 110 is closed at one longitudinal end by a base 102. The connector 115 protrudes from this base. Four measuring electrodes 170 are embedded in this base 102 and are accessible from the outside, as can be seen in the perspective view of Figure 39. Figure 40 shows an interior view of the base 102. The measuring electrodes 170 are also visible there, so that they make contact with a fluid located in the sample chamber 110. This makes it possible, for example, to apply a current through two of the measuring electrodes 170 and to measure the voltage with the other two.

[0180] Figures 41 and 42 show an embodiment which, in comparison to the embodiment of Figures 39 and 40, has only two measuring electrodes 170.

[0181] The steps of the method according to the invention can be carried out in the specified order. However, they can also be carried out in a different order, provided this is technically feasible. The method according to the invention can be carried out in one embodiment, for example with a specific combination of steps, in such a way that no further steps are performed. However, further steps can also be carried out in principle, including those not mentioned.

[0182] It should be noted that features may be described in combination in the claims and description, for example to facilitate understanding, even though they can also be used separately. The person skilled in the art recognizes that such features can also be combined independently with other features or combinations of features.

[0183] Cross-references in dependent claims may identify preferred combinations of the respective features, but do not exclude other combinations of features. The following features are presented in a structured manner. These can be considered independent aspects of the invention. They can be combined arbitrarily with each other and with other features disclosed herein.

[0184] 1. Measuring device (100) for analyzing a fluidic sample, wherein the measuring device (100) comprises the following:

[0185] a sample chamber (110) for receiving the sample,

[0186] a piston (120) which is movable within the sample chamber (110), wherein when the piston (120) is moved in a first direction the sample is drawn into the sample chamber (110) and when the piston (120) is moved in a second direction, which is different from the first direction, the sample is pushed out of the sample chamber (110),

[0187] a drive device (125) for moving the piston (120), and

[0188] a measuring instrument (210, 220) or several measuring instruments (210, 220), wherein each measuring instrument (210, 220) is configured to optically measure at least one measurement quantity on the sample located in the sample chamber (110).

[0189] 2. Measuring device (100) according to feature 1,

[0190] which has one or more brackets (141, 142),

[0191] wherein one or more measuring instruments (210, 220) are attached to one, some or all of the brackets (141, 142), and

[0192] wherein the holders (141 , 142) are detachably attached to another component of the measuring device (100).

[0193] 3. Measuring device (100) according to feature 2,

[0194] wherein one, some or all of the supports (141 , 142) are arranged surrounding the sample chamber (110) and / or at a distance from the sample chamber (110).

[0195] 4. Measuring device (100) according to one of features 2 or 3,

[0196] wherein one, some or all of the supports (141, 142) are annular in design; and / or

[0197] wherein one, some or all of the supports (141, 142) are rectangular or square in plan view. Measuring device (100) according to one of features 2 to 4,

[0198] wherein the supports (141 , 142) can be removed and attached parallel to a longitudinal extension of the sample chamber (110).

[0199] Measuring device (100) according to one of features 2 to 5,

[0200] wherein the measuring device (100) has a fastening device (160) to which each of the holders (141, 142) can be attached.

[0201] Measuring device (100) according to one of features 2 to 6,

[0202] wherein each holder (141, 142), or at least one holder (141, 142) or several holders (141, 142), each has a fastening device (160) to which each other of the holders (141, 142) can be attached.

[0203] Measuring device (100) according to feature 6 and / or feature 7,

[0204] the fastening devices (160) are identical.

[0205] Measuring device (100) according to one of features 6 to 8,

[0206] wherein the fastening devices (160) each have a bearing surface (162) which is oriented transversely to a longitudinal extent of the sample chamber (110) and / or is oriented transversely to a direction in which the supports (141, 142) can be removed and attached.

[0207] Measuring device (100) according to one of features 6 to 9,

[0208] wherein the fastening devices (160) each have a circumferential projection (164) for the attachment of a holder (141, 142), wherein the circumferential projection (164) extends parallel to a longitudinal extent of the sample chamber (110) and / or extends parallel to a direction in which the holders (141, 142) can be removed and attached.

[0209] Measuring device (100) according to one of features 6 to 10,

[0210] which has a base body (105) from which the sample chamber (110) projects and to which a fastening device (160) is attached. Measuring device (100) according to one of features 2 to 11 ,

[0211] which has a cover (145) for darkening and / or lightproofing a space between sample chamber (110) and one or more supports (141, 142).

[0212] Measuring device (100) according to feature 12,

[0213] wherein the cover (145) is detachably attached to a bracket (141, 142).

[0214] Measuring device (100) according to one of the preceding features,

[0215] wherein at least one measuring device (210, 220) has a light source (212, 222, 223) which is designed to generate a light beam and introduce it into the sample chamber (110).

[0216] Measuring device (100) according to feature 14,

[0217] wherein at least one light source (212, 222, 223) is configured to introduce a light beam through a transparent area (112) of the sample chamber (110).

[0218] Measuring device (100) according to one of features 14 or 15,

[0219] wherein all light sources (212, 222, 223) are arranged completely outside the sample chamber (110) and / or spaced away from the sample chamber (110).

[0220] Measuring device (100) according to one of features 14 to 16,

[0221] which has one or more optical fibers, each of which is optically coupled to one or more light sources (212, 222, 223) or light sources (212, 222, 223) and directs light from these light sources (212, 222, 223) onto the sample chamber (110).

[0222] Measuring device (100) according to one of the preceding features,

[0223] wherein at least one measuring device (210, 220) has a detector (214, 216, 224, 226) which is configured to detect light emerging from the sample chamber (110) and to measure the measured quantity based thereon. Measuring device (100) according to feature 18,

[0224] wherein at least one detector (214, 216, 224, 226) is configured to detect light emanating from a transparent area (112) of the sample chamber (110).

[0225] Measuring device (100) according to one of features 18 or 19,

[0226] wherein all detectors (214, 216, 224, 226) are arranged completely outside the sample chamber (110) and / or spaced apart from the sample chamber (110).

[0227] Measuring device (100) according to one of features 18 to 20,

[0228] which has one or more optical fibers, each of which is optically coupled to one detector (214, 216, 224, 226) or several detectors (214, 216, 224, 226) and directs light from the sample chamber (110) to these detectors (214, 216, 224, 226).

[0229] Measuring device (100) according to one of the preceding features,

[0230] wherein at least one measuring instrument (210, 220) is designed to measure light transmitted through the sample and / or scattered in the sample.

[0231] Measuring device (100) according to one of the preceding features,

[0232] wherein the sample chamber (110) has a completely continuous flat surface on the inside for guiding the piston (120).

[0233] Measuring device (100) according to one of the preceding features,

[0234] which has a multiple valve (130) which has several ports (132) that can be selectively switched to connect to the sample chamber (110).

[0235] Measuring device (100) according to feature 24,

[0236] which has a valve actuator (135) for switching the multiple valve (130). Measuring device (100) according to one of features 24 or 25, wherein at least one port (132) of the multiple valve (130) is connected to ambient air and / or to an air reservoir for drawing air into the sample chamber (110).

[0237] Measuring device (100) according to one of the features 24 to 26,

[0238] wherein the multiple valve (130) and / or the valve actuator (135) are arranged at a longitudinal end of the sample chamber (110) opposite the actuator (125).

[0239] Measuring device (100) according to one of features 24 to 27,

[0240] which has at least one reservoir (150) for a reagent,

[0241] wherein each reservoir (150) is connected to a port (132) of the multiple valve (130) for drawing the reagent into the sample chamber (110).

[0242] Measuring device (100) according to one of the preceding features,

[0243] wherein the piston (120) seals against an inner surface of the sample chamber (110) on the outside.

[0244] Measuring device (100) according to one of the preceding features,

[0245] wherein the piston (120) has a seal on the outside which rests against an inside surface of the sample chamber (110).

[0246] Measuring device (100) according to one of the preceding features,

[0247] wherein the piston (120) is designed for internal cleaning of the sample chamber (110).

[0248] Measuring device (100) according to one of the preceding features,

[0249] where the first direction is opposite to the second direction.

[0250] Measuring device (100) according to one of the preceding features,

[0251] wherein the drive device (125) is designed as an electric motor with a rotary-translation gearbox. Measuring device (100) according to one of the preceding features,

[0252] wherein the sample chamber (110) has a completely or at least partially constant internal cross-section along a longitudinal extent.

[0253] Measuring device (100) according to one of the preceding features,

[0254] wherein the sample chamber (110) has a completely or at least partially round inner and / or outer cross-section.

[0255] Measuring device (100) according to one of the preceding features,

[0256] wherein the sample chamber (110) has a rectangular or square internal cross-section and / or external cross-section completely or at least partially.

[0257] Measuring device (100) according to one of the preceding features,

[0258] wherein the sample chamber (110) is cylindrical in shape.

[0259] Measuring device (100) according to one of the preceding features,

[0260] wherein the sample chamber (110) is at least partially, or completely, optically transparent.

[0261] Measuring device (100) according to one of the preceding features,

[0262] wherein the measuring device (100) is designed to analyze a liquid sample, water and / or a gas.

[0263] Fluid supply system (10), comprising

[0264] a line (20) for fluid,

[0265] a sampling device (21, 22) for extracting fluid from the line (20), and

[0266] A measuring device (100) according to one of the preceding features, wherein the sampling device (21, 22) is configured to extract fluid from the line (20) and supply it to the measuring device (100) for analysis. Fluid supply system (10) according to feature 40.

[0267] which is designed as a liquid supply system, a water supply system and / or a gas supply system.

[0268] Fluid supply system (10) according to feature 41 ,

[0269] wherein the fluid supply system (10) comprises one or more filter systems (30), and

[0270] wherein in one, some or all filter systems (30) a sampling device (21 , 22) is arranged upstream and / or downstream of the filter system, each of which is connected to a connection (132) of a multiple valve (130) of the measuring device (100).

[0271] Method for analyzing a sample using a measuring device (100) according to one of features 1 to 39, wherein the method comprises the following steps: drawing the sample into the sample chamber (110) by moving the piston (120) in the first direction, then

[0272] Perform at least one measurement using at least one measuring device (210, 220) on the sample located in the sample chamber (110), and then push the sample out of the sample chamber (110) by moving the piston (120) in the second direction.

[0273] Procedure according to feature 43,

[0274] which further includes the following step:

[0275] Perform at least one reference measurement using at least one measuring device (210, 220) without a sample in the sample chamber (110).

[0276] Method according to one of features 43 or 44,

[0277] which further includes the following steps:

[0278] Moving the piston (120) in the first direction without drawing in a sample and while drawing in air, or while drawing in a reference gas, or while drawing in a reference liquid, then

[0279] Perform at least one reference measurement using at least one measuring device (210, 220) without a sample in the sample chamber (110), and then move the piston (120) in the second direction.

[0280] Method according to one of features 44 or 45,

[0281] wherein the reference measurement is carried out with the sample chamber (110) filled with air or with the sample chamber (110) filled with a reference gas or a reference liquid.

[0282] Method according to one of features 45 or 46,

[0283] where the reference gas is an inert gas, nitrogen, a noble gas, helium, neon, argon and / or krypton,

[0284] and / or

[0285] where the reference liquid is ultrapure water, distilled water and / or deionized water.

[0286] Method according to one of features 43 to 47,

[0287] which further includes the following steps:

[0288] Aspirating a cleaning fluid into the sample chamber (110) by moving the piston (120) in the first direction, and then pushing the cleaning fluid out of the sample chamber (110) by moving the piston (120) in the second direction.

[0289] Method according to one of features 43 to 48,

[0290] wherein several measurements are sequentially performed on the sample located in the sample chamber (110) using a measuring device (210, 220). Reference numeral list

[0291] 10 Fluid supply system 20 Line

[0292] 21 Sampling device 22 Sampling device 30 Filter system

[0293] 100 measuring device

[0294] 102 Floor

[0295] 110 Sample chamber

[0296] 112 transparent areas 115 connectors

[0297] 116 Secondary connection

[0298] 117 Secondary connection

[0299] 118 Secondary connection

[0300] 120 pistons

[0301] 122 Piston rod

[0302] 125 Drive unit 130 Multiple valve

[0303] 132 connections

[0304] 135 Valve actuator

[0305] 141 first bracket

[0306] 142 second bracket

[0307] 144 Closure

[0308] 145 Cover

[0309] 147 Recording Room

[0310] 150 Reservoir

[0311] 160 Fastening device 162 Support surface

[0312] 164 lead

[0313] 170 Measuring electrode

[0314] 210 first measuring device 212 light source

[0315] 214 Detector

[0316] 216 further detector second measuring device light source further light source detector further detector

Claims

Patent claims 1. Measuring device (100) for analyzing a fluidic sample, wherein the measuring device (100) comprises the following: a sample chamber (110) for receiving the sample, a piston (120) which is movable within the sample chamber (110), wherein when the piston (120) is moved in a first direction the sample is drawn into the sample chamber (110) and when the piston (120) is moved in a second direction, which is different from the first direction, the sample is pushed out of the sample chamber (110), a drive device (125) for moving the piston (120), and a measuring instrument (210, 220) or several measuring instruments (210, 220), wherein each measuring instrument (210, 220) is designed to optically measure at least one measurement quantity on the sample located in the sample chamber (110).

2. Measuring device (100) according to claim 1 , which has one or more brackets (141, 142), wherein one or more measuring instruments (210, 220) are attached to one, some or all of the brackets (141, 142), and wherein the holders (141 , 142) are detachably attached to another component of the measuring device (100).

3. Measuring device (100) according to claim 2, wherein one, some or all of the supports (141 , 142) are arranged surrounding the sample chamber (110) and / or at a distance from the sample chamber (110).

4. Measuring device (100) according to one of claims 2 or 3, wherein one, some or all of the supports (141, 142) are designed in a ring shape in plan view; and / or wherein one, some or all of the supports (141 , 142) are rectangular or square in plan view.

5. Measuring device (100) according to one of claims 2 to 4, wherein the supports (141 , 142) can be removed and attached parallel to a longitudinal extension of the sample chamber (110).

6. Measuring device (100) according to one of claims 2 to 5, wherein the measuring device (100) has a fastening device (160) to which each of the holders (141, 142) can be attached.

7. Measuring device (100) according to one of claims 2 to 6, wherein each holder (141, 142), or at least one holder (141, 142) or several holders (141, 142), each has a fastening device (160) to which each other of the holders (141, 142) can be attached.

8. Measuring device (100) according to claim 6 and / or claim 7, the fastening devices (160) are identical.

9. Measuring device (100) according to one of claims 6 to 8, wherein the fastening devices (160) each have a contact surface (162) which points towards a holder (141, 142) to be attached to the respective fastening device (160), and / or which contacts a holder (141, 142) to be attached to the respective fastening device (160), and / or which is oriented transversely to a longitudinal extent of the sample chamber (110) and / or is oriented transversely to a direction in which the holders (141, 142) can be removed and attached.

10. Measuring device (100) according to one of claims 6 to 9, wherein the fastening devices (160) each have a circumferential projection (164) for the attachment of a bracket (141, 142).

11. Measuring device (100) according to claim 10, wherein the circumferential projection (164) extends parallel to a longitudinal extent of the sample chamber (110) and / or extends parallel to a direction in which the supports (141 , 142) can be removed and attached.

12. Measuring device according to one of claims 10 or 11 , wherein the projection (164) is arranged radially inside a holder (141, 142) to be attached to the fastening device (160).

13. Measuring device according to one of claims 10 to 12, wherein the circumferential projection (164) is ring-shaped or rectangular in plan view.

14. Measuring device (100) according to one of claims 6 to 13, which has a base body (105) from which the sample chamber (110) extends and to which a fastening device (160) is attached.

15. Measuring device (100) according to one of claims 2 to 14, which has a cover (145) for darkening and / or lightproofing a space between sample chamber (110) and one or more supports (141, 142).

16. Measuring device (100) according to claim 15, wherein the cover (145) is detachably attached to a bracket (141, 142).

17. Measuring device (100) according to one of the preceding claims, which has a multiple valve (130) which has several ports (132) that can be selectively switched to connect to the sample chamber (110).

18. Measuring device (100) according to claim 17, which has a valve actuator (135) for switching the multiple valve (130).

19. Measuring device (100) according to one of claims 17 or 18, wherein at least one port (132) of the multiple valve (130) is connected to ambient air and / or to an air reservoir for drawing air into the sample chamber (110).

20. Measuring device (100) according to one of claims 17 to 19, wherein the multiple valve (130) and / or the valve actuator (135) are arranged at a longitudinal end of the sample chamber (110) opposite the actuator (125).

21. Measuring device (100) according to one of claims 17 to 20, which has at least one reservoir (150) for a reagent, wherein each reservoir (150) is connected to a port (132) of the multiple valve (130) for drawing the reagent into the sample chamber (110).

22. Measuring device (100) according to one of claims 17 to 21 , wherein one, some or all of the ports (132) protrude from the multiple valve (130) perpendicular to a direction of movement of the piston (120).

23. Measuring device (100) according to one of the preceding claims, wherein a secondary connection (116, 117) for supplying and / or discharging fluid is provided in the sample chamber (110), or wherein a first auxiliary connection (116) for supplying and / or discharging fluid and a second auxiliary connection (117) for supplying and / or discharging fluid are provided in the sample chamber (110).

24. Measuring device (100) according to claim 23, wherein the first auxiliary connection (116) and the second auxiliary connection (117) are arranged at opposite longitudinal ends of the sample chamber (110).

25. Measuring device (100) according to one of claims 23 or 24, wherein the piston (120) is designed to close at least one auxiliary port (116, 117) in one position and to release it in another position.

26. Measuring device (100) according to one of the preceding claims, wherein a secondary connection (118) for supplying and / or discharging fluid is formed in the piston (120) and / or a piston rod (122).

27. Measuring device (100) according to one of the preceding claims, wherein one or more measuring electrodes (170) are arranged in the sample chamber (110) for carrying out electrical measurements on fluid located in the sample chamber (110).

28. Measuring device (100) according to claim 27, wherein two or four measuring electrodes (170) are arranged in the sample chamber (110).

29. Fluid supply system (10), comprising a line (20) for fluid, a sampling device (21, 22) for extracting fluid from the line (20), and a measuring device (100) according to one of the preceding claims, wherein the extraction device (21 , 22) is configured to extract fluid from the line (20) and supply it to the measuring device (100) for analysis.

30. Fluid supply system (10) according to claim 29, which is designed as a liquid supply system, a water supply system and / or a gas supply system.

31. Fluid supply system (10) according to claim 30, wherein the fluid supply system (10) comprises one or more filter systems (30), and wherein in one, some or all filter systems (30) a sampling device (21, 22) is arranged upstream and / or downstream of the filter system (30), each of which is connected to a connection (132) of a multiple valve (130) of the measuring device (100).

32. Method for analyzing a sample using a measuring device (100) according to any one of claims 1 to 28, wherein the method comprises the following steps: drawing the sample into the sample chamber (110) by moving the piston (120) in the first direction, then Perform at least one measurement using at least one measuring device (210, 220) on the sample located in the sample chamber (110), and then push the sample out of the sample chamber (110) by moving the piston (120) in the second direction.

33. Method according to claim 32, which further includes the following step: Perform at least one reference measurement using at least one measuring device (210, 220) without a sample in the sample chamber (110).

34. Method according to one of claims 32 or 33, which further includes the following steps: Moving the piston (120) in the first direction without drawing in a sample and while drawing in air, or while drawing in a reference gas, or while drawing in a reference liquid, then Perform at least one reference measurement using at least one measuring device (210, 220) without a sample in the sample chamber (110), and then Moving the piston (120) in the second direction.

35. Method according to one of claims 33 or 34, wherein the reference measurement is carried out with the sample chamber (110) filled with air or with the sample chamber (110) filled with a reference gas or a reference liquid.

36. Method according to one of claims 34 or 35, where the reference gas is an inert gas, nitrogen, a noble gas, helium, neon, argon and / or krypton, and / or where the reference liquid is ultrapure water, distilled water and / or deionized water.

37. Method according to any one of claims 32 to 36, which further includes the following steps: Aspirating a cleaning fluid into the sample chamber (110) by moving the piston (120) in the first direction, and then pushing the cleaning fluid out of the sample chamber (110) by moving the piston (120) in the second direction.

38. Method according to any one of claims 32 to 37, wherein several measurements on the sample located in the sample chamber (110) are carried out sequentially and / or in parallel using a measuring device (210, 220).

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