Sensor Device

Abstract

A method and sensor apparatus 1;1' for detecting the position of a liquid surface in a vessel configured to be mounted to a top opening 11;11' of a vessel 13;13' used for storing liquid in a bench-top fluid handling system 101. The sensor apparatus 1;1' comprises a millimeter wave radar sensor 21, a sensor housing 24 comprising the radar sensor 21, and a vessel mounting portion 23;23' connected to the sensor housing 24 and configured to mount the sensor apparatus 1;1' to the top opening 11;11' of the vessel 13;13' such that the radar sensor 21 can be placed in an operational position for detecting the position of a liquid surface in the vessel 13;13'.

Description

[Technical Field]

[0001] Technical field of the invention The present invention relates to a sensor device for detecting the position of a liquid surface in a vessel and a method for detecting the position of a liquid surface in a vessel used to store liquid in a bench-top fluid handling system. [Background technology]

[0002] background In fluid handling systems, such as liquid analysis systems, separation systems, and chromatography systems, it is important to track the contents of bottles and other containers for various liquids, such as solvents and waste products, handled within the system. If a container runs empty, the process can be disrupted; if a container is overfilled, liquid can be wasted and contamination issues can arise. Liquid overflow can also be a safety hazard, carrying the risk of personal injury. In these types of systems, there are various commonly used methods for monitoring the liquid level within a container. One possibility is dead reckoning, i.e., using information from a pump in the system regarding how much liquid is being pumped to or from the container. However, in such systems, it is important for the user to constantly and accurately update the contents of the container when it is refilled or emptied.

[0003] Another method for monitoring liquid level in a chromatography system is disclosed in U.S. Patent No. 7,419,598, in which a bubbler is positioned in a solvent reservoir with an opening near the bottom of the system to measure the solvent pressure and thereby monitor the solvent level. However, this measurement method depends on the density of the liquid and often does not provide measurement accuracy good enough to predict whether the amount of solvent is sufficient to run the method, or whether the remaining empty volume in the waste container is sufficient to run the method.

[0004] U.S. Patent Application Publication No. 2003 / 0175157 discloses a method for controlling fluid contents in a container, in which a weighing scale is used to detect the weight of the fluid in the container. This method also requires knowing or estimating the density of the fluid, especially in the case of mixed fluids such as waste containers, which can result in inaccurate measurement. Furthermore, the weight of the container, the weight of the tubing attached to the container, and any other possible components of the system that come into contact with the container affect the measured weight of the container, thereby affecting measurement accuracy. This also requires the container to be positioned freely without coming into contact with any potentially problematic objects. Summary of the Invention [Problem to be solved by the invention]

[0005] overview SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved sensor apparatus and method for monitoring the liquid level in a vessel.

[0006] A further object of the present invention is to provide a sensor device that is easy to handle and thereby enables reliable monitoring of liquid levels. [Means for solving the problem]

[0007] This is achieved by the sensor device and method according to the independent claims. According to one aspect of the present invention there is provided a sensor apparatus configured to be mounted to a top opening of a vessel used to store liquid in a bench-top fluid handling system, said sensor apparatus comprising: a millimeter wave radar sensor; a sensor housing including the millimeter wave radar sensor; a container mounting portion connected to the sensor housing and configured to mount the sensor device on an upper opening of the container so that the millimeter wave radar sensor can be placed in an operational position for detecting the position of a liquid surface in the container; Equipped with.

[0008] According to another aspect of the present invention there is provided a method for detecting the position of a liquid surface in a container used to store liquid in a benchtop fluid handling system, said method comprising: attaching a container mounting portion of a sensor device according to the present invention to an upper opening of a container; Detecting the position of a liquid surface within the container when the millimeter wave radar sensor is in an operating position; Includes.

[0009] This allows reliable monitoring of the liquid level in the container by directly measuring the distance to the liquid level, thereby measuring the liquid level of all types of liquids and liquid mixtures, regardless of their density. According to the present invention, a millimeter-wave radar sensor is used. This is a type of radar technology that transmits short-wavelength signals in the millimeter range. The short wavelength allows for smaller system components, thereby providing a small, compact radar sensor with high accuracy. The radar sensor can operate at frequencies between 55 and 85 GHz, for example. This type of radar sensor can measure closer distances than previous types of radar sensors, which were larger and bulkier and not suitable for small containers. According to the present invention, such a millimeter-wave radar sensor can be attached to the top opening of the container, thereby monitoring the liquid level in the container. This is a direct measurement of the liquid level, independent of the liquid's density, thereby providing good measurement accuracy and reliability for both clean liquids and liquid mixtures, such as waste containers. This effectively avoids both empty runs and overfilling the container. This makes the fluid handling process in the system more efficient and reduces the risk of contamination and personal injury from overfilling the waste container. By positioning the millimeter-wave radar sensor attached to the top opening of the container, the radar sensor is positioned at an appropriate distance above the liquid level in the container, allowing the liquid level to be measured accurately and conveniently at all times. This allows the user to always know how much liquid is in the container, allowing the user to easily see whether the liquid is sufficient to carry out a process. Furthermore, the user does not need to manually enter any information regarding the volume of the liquid, which makes it easier for the user to handle and reduces the risk of error.

[0010] According to one embodiment of the present invention, the sensor housing can be positioned in at least two different positions relative to the container mount, one of which is a closed position in which the sensor housing covers at least a portion of the top opening of the container, and another of which is an open position in which the sensor housing does not cover the top opening, and the radar sensor is in an operative position when the sensor housing is in the closed position, thereby allowing the container to be refilled with new liquid without removing the entire sensor device, and only requiring the sensor housing to be in the open position during refilling.

[0011] According to one embodiment of the invention, the sensor housing is connected within the sensor device by a hinge that allows the sensor housing to be flipped from a closed position to an open position to allow access to the top opening of the container.

[0012] According to one embodiment of the present invention, the sensor housing includes an angle sensor, which can detect the tilt angle of the sensor housing and / or the entire container. The tilt angle of the sensor housing can indicate whether the sensor housing is in a closed or open position. The tilt angle of the entire container may indicate that the container is mispositioned or that a user is tilting the container to use the last of its contents.

[0013] According to one embodiment of the invention, the sensor apparatus further comprises a position indicating device configured to indicate whether the radar sensor is in an operating position, which in one embodiment is an angle sensor.

[0014] According to one embodiment of the present invention, the sensor device further comprises a tube holder part that can be attached to the container mounting part and is configured to hold a tube provided in the container towards one side of the top opening, thereby enabling the tube to be kept away from the measurement path between the radar sensor and the liquid level, which would otherwise get in the way and interfere with liquid level detection.

[0015] According to one embodiment of the present invention, the tube holder portion includes a rail extending from the top opening of the container into and out of the container when the sensor device is installed in the container, and the rail can support one or more tubes installed in the container. This allows the tubes to be held in an appropriate position within the container. The tubes can also be oriented in an appropriate direction from the container, which makes connection in the system easier. The tubes can also be positioned and held at an appropriate height within the container, which eliminates the risk of the tubes moving to a position above the liquid level in the container.

[0016] According to one embodiment of the present invention, the tube holder portion further comprises a ring-shaped fixture connected to the rail, the ring-shaped fixture being disposed between the container mounting portion and the sensor housing when the sensor housing is disposed in the closed position, whereby the ring-shaped fixture is connected to the container mounting portion so as to be rotatable relative to the container mounting portion and to the sensor housing so that the housing portion can be disposed in at least two different positions relative to the container mounting portion, the two positions including an open position and a closed position. By rotating the ring-shaped fixture together with the rail, the tube mounted on the rail can be oriented as needed within the connected system while the container mounting portion is maintained in a predetermined position attached to the container.

[0017] According to one embodiment of the present invention, the sensor device comprises a processor connected to a radar sensor, the processor being configured to determine the amount of liquid in the container based on the detected position of the liquid surface and based on pre-stored container shape information. By distributing intelligence to the sensor device, communication from the sensor device to an external control system is less complex and more robust, i.e., less capacitance is required and smaller, cheaper cables can be used for that communication.

[0018] According to one embodiment of the invention, the container attachment comprises a thread for a threaded connection to a top opening of a container that comprises a screw thread, or a magnet for a magnetic connection to a top opening of a container.

[0019] According to one embodiment of the present invention, the sensor apparatus further comprises a connection device by which the radar sensor and possibly a processor and / or angle sensor can be connected to a control system in a benchtop fluid handling system in which the vessel and sensor apparatus are used.

[0020] According to one embodiment of the present invention, the sensor device is configured to be mounted in a vessel having a height of 10-100 cm and / or a volume of 0.5-20 liters, making the sensor device suitable for use in benchtop fluid handling systems such as chromatography systems.

[0021] According to one embodiment of the invention, the method further comprises positioning one or more tubes provided in the container in a tube holder portion of the sensor device.

[0022] According to one embodiment of the present invention, the method further includes rotating the tube holder portion relative to the container mounting portion so that the tubing provided in the tube holder portion is oriented for convenient connection in a benchtop fluid handling system.

[0023] According to one embodiment of the invention, the method further comprises indicating by a position-indicating device whether the radar sensor is in an operational position. According to one embodiment of the invention, indicating by a position-indicating device whether the radar sensor is in an operational position comprises measuring an angle of tilt of the sensor housing, the position-indicating device comprising an angle sensor provided on the sensor housing.

[0024] According to one embodiment of the present invention, the method comprises: positioning a sensor housing of the sensor device in a closed position relative to a container mounting portion to detect a liquid level in the container, the closed position being a position where the sensor housing covers at least a portion of an upper opening of the container, and the radar sensor being in an operative position when the sensor housing is in the closed position; positioning a sensor housing of the sensor device in an open position relative to the container mount to refill the container with liquid, the open position being a position where the sensor housing does not cover the top opening; Further includes:

[0025] Further embodiments are set forth in the detailed description and dependent claims. [Brief explanation of the drawings]

[0026] [Figure 1] 1 illustrates schematically a bench-top fluid handling system in which a sensor device according to the present invention may be used; [Figure 2a] 1 shows a perspective view of a sensor device according to an embodiment of the present invention; [Figure 2b] 2b shows a cross-sectional view of the sensor device shown in FIG. 2a. [Figure 3a] FIG. 2c is a perspective view of a container fitted with the sensor device shown in FIGS. 2a and 2b in a closed position; [Figure 3b] The same container and the same sensor device as shown in Figure 3a, with the sensor device in an open position. [Figure 3c] 3b is a cross-sectional view of a container fitted with the sensor device shown in FIG. 3a; [Figure 3d] FIG. 3b is an enlarged view of a cross section of the sensor device shown in FIG. 3c. [Figure 4a] FIG. 10 is a perspective view of a sensor device according to another embodiment of the present invention. [Figure 4b] 4b is a perspective view showing only a part of the sensor device shown in FIG. 4a; FIG. [Figure 5a] FIG. 4c is a perspective view of a container fitted with the sensor device shown in FIGS. 4a and 4b, in a closed position; [Figure 5b] The same container and the same sensor device as shown in Figure 5a, with the sensor device in an open position. [Figure 5c] 5b is a cross-sectional view of a container fitted with the sensor device shown in FIG. 5a. [Figure 6] 1 is a flowchart of a method according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] Detailed Description of the Embodiments FIG. 1 shows a benchtop fluid handling system 101 in which a sensor device 1;1′ according to the present invention can be used when attached to a container 13;13′ used to store liquid in the benchtop fluid handling system 101. In this particular example, the benchtop fluid handling system 101 is a chromatography system 101, e.g., a lab chromatography system, also known as a small-scale chromatography system, whereby one or more chromatography columns 103 can be connected to the chromatography system 101. In other types of benchtop fluid handling systems in which the present invention can be used, other types of components for processing or analyzing fluids can be connected to the system instead of a chromatography column. Other examples of benchtop fluid handling systems include, for example, filter systems, evaporation systems, and other types of separation and analysis systems. The chromatography system 101 further comprises one or more pumps 113 for pumping liquid to and from the container 13;13′ and the chromatography column 103. Fluid lines 114 connect the vessels 13; 13′ with one or more chromatography columns 103. The chromatography system 101 further comprises a control system 111 and, optionally, a display 112. The display may be suitable for presenting information to a user, but may be replaced by other alternatives, such as a visual or audible signal, an automatic shutoff, and / or connection to the display of a connected device, such as a computer or phone. The control system 111 is connected to the display 112, one or more pumps 113, and one or more sensor devices 1; 1′. The control system 111 may collect information about the liquid level in the vessels 13; 13′ from both the one or more sensor devices 1; 1′ and, optionally, information about the pumped volume to or from the vessels 13; 13′ from the one or more pumps 113. The control system 111 may further suitably present information about the liquid level on the display 112 and control the one or more pumps 113 accordingly.

[0028] Two different embodiments of the sensor device 1 and 1' are shown in Figures 2-5. In Figures 2-3, the sensor device 1 includes a container mounting portion 23 with a threaded connection 61 configured to be attached to a container 13 having a threaded top opening 11. The top opening 11 is located at the top of the container 13 and may also be referred to as a fill hole or inlet. For containers without a threaded top opening, an adapter can be used to provide a threaded top opening suitable for connection to a sensor device according to the present invention. Such an adapter has a thread that matches the thread of the container mounting portion of the sensor device according to the present invention and has a threaded portion to be positioned within the container opening. In Figures 4-5, the sensor device 1' includes a container mounting portion 23' with a magnet 61'. This is a sensor device 1' suitable for connection to a container having a top opening 11' without a thread. If the container is a metal container, a magnetic connection may be appropriate. Other possible connections may include a snap connection, a clamp connection, or a screw connection. Most of the other details of the sensor devices 1;1' are the same, and therefore the same or similar reference numbers are given to the details of the two different embodiments, and the invention will be described below with reference to all the drawings.

[0029] According to the present invention, a sensor device 1;1' is provided that is configured to be attached to the top opening 11;11' of a container 13;13' used to store liquid in a benchtop fluid handling system 101. The sensor device 1;1' includes a millimeter-wave radar sensor 21, a new type of radar sensor that is small and compact and can be used to measure significantly smaller distances compared to larger conventional radar sensors. A millimeter-wave radar sensor is a type of radar technology that transmits signals with short wavelengths in the millimeter range. The short wavelength allows for smaller system components, thereby providing a radar sensor that is small and compact and capable of measuring with greater accuracy. The radar sensor can operate at, for example, 55-85 GHz. The millimeter-wave radar sensor can be, for example, a pulsed coherent radar sensor operating at 60 GHz, or 55-80 GHz, or 55-65 GHz, or another type of millimeter-wave radar sensor, also known as a miniature radar sensor. Previous types of radar sensors were larger and bulkier and not suitable for use with smaller containers. The millimeter-wave radar sensor can be provided as a single-chip solution containing all necessary components within one chip, making it a small, compact, and easily integrated radar sensor suitable for the present invention. According to the present invention, it is realized that this type of millimeter-wave radar sensor can be used in benchtop fluid handling systems for reliable and highly accurate liquid level monitoring with smaller vessels, for example, vessels with heights ranging from 10 to 100 cm and / or volumes ranging from 0.5 to 220 liters or 0.5 to 20 liters. According to the present invention, the millimeter-wave radar sensor 21, hereinafter simply referred to as radar sensor 21, is provided in a sensor device 1;1' configured to be attached to the top opening 11;11' of a vessel 13;13', thereby achieving simple and reliable liquid level monitoring.

[0030] The sensor device 1;1' comprises a sensor housing 24 comprising said radar sensor 21, and a vessel mounting portion 23;23' connected to the sensor housing 24 and configured to mount the sensor device 1;1' to a vessel 13;13' such that the radar sensor 21 can be placed in an operational position for detecting the position of a liquid surface in the vessel 13;13'. As mentioned above, the vessel mounting portion 23;23' may comprise various types of connection means depending on the type of vessel to be mounted, such as a screw thread 61 for a vessel 13 having a threaded top opening 11, or a magnet 61' for a metal vessel.

[0031] According to some embodiments of the present invention, and as shown in both embodiments of FIGS. 2-5, the sensor apparatus 1;1' further includes a position-indicating device 25 configured to indicate whether the radar sensor 21 is in the operating position. By detecting the correct position of the radar sensor 21, i.e., by detecting whether the radar sensor 21 is positioned in the correct operating position, monitoring of the liquid level in the container can be more reliably performed. For example, if the sensor apparatus 1;1' is moved or removed to refill the container 13, the radar sensor 21 may not be able to accurately read the liquid level during this time, and it is useful to identify those periods when the radar sensor 21 is not in the correct operating position. During such periods, dead reckoning, i.e., information from one or more pumps 113 in the system 101, can be used to estimate the liquid level in the container when the radar sensor 21 is not positioned in the correct operating position, so that the process can continue, for example, during refilling of the container. However, once the correct operating position is again indicated by the position-indicating device 25, the liquid level can be updated with a reading from the radar sensor. The position indication device 25 may, for example, comprise an angle sensor 25' or another type of sensor capable of detecting the position of the radar sensor 21 or the position of the sensor housing 24 comprising said radar sensor 21, which will be described in more detail below.

[0032] In some embodiments of the present invention, and as shown in both of the embodiments in FIGS. 2-5, the sensor housing 24 can be positioned in at least two different positions relative to the container mounting portion 23;23'. One position is a closed position in which the sensor housing 24 covers at least a portion of the top opening 11;11' of the container 13;13', and the other position is an open position in which the sensor housing 24 does not cover the top opening 11;11'. The radar sensor 21 is in an operative position when the sensor housing 24 is in the closed position. When the sensor housing 24 is in the open position, the top opening 11;11', or at least a portion of the top opening 11;11', is exposed, i.e., the container is accessible, allowing the container to be filled and / or refilled with liquid. This allows the container to be refilled without removing the entire sensor device 1;1'. In the open position, only the sensor housing 24 is required. This allows the tube 41 provided within the container 13;13' to remain within the container during refilling.

[0033] The sensor housing 24 encloses the radar sensor 21 and other components provided within the sensor housing, such as a suitable lens 26 provided to focus electromagnetic waves from the radar sensor. This can be, for example, a hyperbolic lens or an FZP (Fresnel Zone Plate) lens. Furthermore, the sensor housing 24 can include a processor 31 connected to the radar sensor 21 and, optionally, an angle sensor 25′, which will be described in more detail below. The material of the sensor housing 24 can be a material, such as a plastic material, that allows the radar sensor 21 to transmit and receive electromagnetic waves. Suitably, the material is also resistant to chemical vapors that may be present in the contents of the container. Examples of suitable materials for the sensor housing are PEEK (Polyether Ether Katone), PPS (Polyphenylene Sulfide), and PP (Polypropylene).

[0034] In some embodiments of the present invention, the sensor housing 24 is connected to the sensor device 1;1' by a hinge 27 (as shown in both embodiments in Figures 2-5), which allows the sensor housing 24 to be flipped from a closed position to an open position, allowing access to the top opening 11;11' of the container 13;13'. Another example of the connection of the sensor housing 24 in the sensor device 1;1' can be a swing connection or a magnetic connection. In some embodiments, the sensor device 1;1' further includes a tube holder portion 33, which can be an integral part within the container mounting portion 23;23' or a separate component that can be attached to the container mounting portion 23;23' as shown in the embodiments in Figures 2-5. The tube holder portion 33 is then provided between the sensor housing 24 and the container mounting portion 23;23' and is described in further detail below. The hinge 27 is best seen in Figures 3b and 5b, in which the sensor housing 24 is provided in the open position. In Figures 3a and 5a, the sensor housing 24 is provided in the closed position. Another alternative is to connect the sensor housing 24 to the container mounting part 23; 23', possibly via the tube holder part 33, by a magnet, possibly with an alignment pin for correct alignment. Also, in the example with a magnet, the sensor housing can be provided in a closed position covering the top opening of the container, and the sensor housing can be provided in an open position where it can be removed from the container mounting part, i.e., where at least a portion of the top opening 11; 11' of the container is exposed, allowing access for filling the container. Once the sensor housing 24 is in the open position and the top opening 11; 11' of the container 13; 13' is at least partially exposed, new liquid can be filled into the container.

[0035] As briefly described above, in some embodiments, the sensor housing 24 may include an angle sensor 25′, which can measure the tilt angle of the sensor housing 24. The measured tilt angle can be used to indicate whether the sensor housing 24 is in an open or closed position, i.e., can be used as a position-indicating device 25 to detect whether the radar sensor 21 is in an operative position. This can also be used to identify whether the container 13; 13′ to which the sensor device 1; 1′ is attached is tilted. If the container is tilted, the measurement path between the radar sensor and the liquid surface may not be free, which may interfere with measurements by the radar sensor 21. Therefore, it may be appropriate to warn the user if it is detected that the container may be tilted. The sensor housing 24 according to some embodiments of the present invention includes the hinge 27 described above. The hinge 27 can be provided as an extension of the sensor housing 24, so that if the sensor housing 24 is pulled away from the container mounting portion 23 or 23' and positioned below the container, for example, on a bench or table, the extended hinge 27 prevents the sensor housing 24 from becoming flat. This allows the angle sensor 25' to indicate the tilt angle of the sensor housing 24, i.e., the radar sensor 21, when not in an operational position. This can be advantageous in avoiding erroneous liquid level measurements. Various tilt angle ranges can be pre-stored for various commonly identified situations, such as an incorrectly tilted container, a container tilted to allow the last of the liquid in the container to be used, a removed sensor housing placed on a bench as described above, the sensor housing open position, and the sensor housing closed position, i.e., the radar sensor's operational position. This allows the angle sensor 25' to be used to identify different situations, thereby making liquid level measurements more reliable. In some embodiments, the angle sensor 25' can measure and distinguish tilts along different axes, such as both the x-axis and the y-axis. This can make it easier to distinguish between various possible situations, such as the position of the sensor housing and the tilt of the entire container.The tilt of the entire vessel can often include tilt about multiple axes, in some cases. The angle sensor 25' can be connected to the processor 31 in the sensor housing 24 and / or to the control system 111 in the separation system 101. Another alternative for the position-indicating device 25 can be a sensor provided on either of the vessel mounting portions 23; 23', or a sensor in the sensor housing 24, where the sensor can detect, for example, mechanically, magnetically, or optically, that one of the two components has come into proximity with the other.

[0036] As briefly described above, the sensor device 1;1' may, in some embodiments (and as shown in both embodiments in Figures 2-5), include a tube holder portion 33. The tube holder portion 33 may be a separate or integral part of the container mounting portion 23;23'. In some embodiments, the tube holder portion 33 may be a detachable portion that can be attached to and detached from the container mounting portion 23;23'. The tube holder portion 33 is configured to hold a tube 41 disposed within the container 13;13' toward one side of the top opening 11;11'. This ensures that, when the sensor device 1;1' is attached to the container, the radar sensor 21 has a free measurement path, unobstructed by the tube 41, between the radar sensor 21 and the liquid surface within the container 13;13' when the sensor device 1;1' is disposed in the operative position.

[0037] In these embodiments, the tube holder portion 33 includes a rail 34 extending from the top opening 11; 11' of the container 13; 13' into and out of the container when the sensor device 1; 1' is mounted on the container. The rail 34 can support one or more tubes 41 mounted on the container. The rail 34 can suitably extend, for example, at least 5 cm or at least 6 cm from the top opening 11; 11' toward the bottom 42 of the container 13; 13'. In some embodiments, the rail 34 is curved so that the tubes 41 mounted on the tube holder portion 33 are guided away from the measurement path between the radar sensor and the liquid surface. The rail 34 can suitably have a length such that, when mounted on the container 13; 13', it extends downward toward the bottom 42 of the container at least a distance sufficient to pass over the neck of a necked container, such as a bottle. This prevents the tube 41 held by the rail 34 from being pushed out of the measurement passage and bending back into the measurement passage as may occur if the rail 34 were to bend and become too short to extend downwards past the neck of the container. Suitably, the sensor device 1;1' can be designed to fit different sized containers so that when the sensor device is attached to a container the length of the rail 34 measured from the top opening of the container towards the bottom of the container may be, for example, at least 5 cm or at least 6 cm in one embodiment of the invention, and at least 8 cm in other embodiments of the invention.

[0038] In the embodiment shown in FIGS. 2-5, the tube holder portion 33 further includes a ring-shaped fixing portion 35 connected to the rail 34, which is located between the container mounting portion 23; 23' and the housing portion 24. However, other designs for attaching the rail 34 to the sensor device 1; 1' are possible. For example, the rail 34 can be an integral part of the container mounting portion 23; 23'. The ring-shaped fixing portion 35 may be connected to the container mounting portion 23; 23' so as to be rotatable relative to the container mounting portion 23; 23', or may be connected to the housing portion 24 so that the housing portion 24 can be positioned in at least two different positions relative to the container mounting portion 23; 23', the two positions including an open position and a closed position. The ring-shaped fixing portion 35 is ring-shaped, i.e., includes an open center, to allow access to the upper opening 11; 11' when the housing portion 24 is positioned in the open position for filling the container 13; 13'. The ring-shaped fastening portion 35 may be connected to the container mounting portion 23; 23' so that it can rotate relative to the container mounting portion, thereby also rotating the housing portion 24 relative to the container mounting portion 23; 23'. This is suitable when the position of the rail 34, and therefore the position of the tube 41 mounted within the container 13; 13', needs to be adjusted. A locking portion 52 may be provided to lock the connection between the ring-shaped fastening portion 35 and the container mounting portion 23; 23'. The housing portion 24 includes a recess 51 for receiving the rail 34. The housing portion 24 and the tube holder portion 33, along with the tube 41, can be removed from the container mounting portion 23; 23' while the container mounting portion 23; 23' remains in place connected to the container 13; 13'. This allows for convenient tube changes. The connection between the ring-shaped fastening portion 35 of the tube holder portion 33 and the sensor housing 24 can be a hinge 27 or a magnetic connection, as described above. This allows the tube 41 mounted on the tube holder part 33 to remain in place within the container while the container is being filled with new liquid, thereby allowing the process to continue while the container 13; 13' is being filled with new liquid.There may be additional snap connections 53 that can be used to secure the closed position of the housing part 24. In FIG. 3b, the snap connections 53 can be seen as two small extensions on the sensor housing 24. These extensions 53 snap into recesses or openings in the tube holder part 33. The snap connections 53 may also be used as an alternative to the position-indicating device 25 to detect the closed position of the housing part 24 and thus the radar sensor 21 being in the operating position. This can be detected by a sensor connected to the snap connections 53. The rails 34 are configured to hold the tubes 41 so that they are maintained in substantially the same position within the container during various processes and for various volumes of contents within the container, i.e., at the same level within the container, often close to the container bottom 42. This is suitable for preventing the tubes from being positioned above the liquid surface within the container.

[0039] In some embodiments, the sensor device comprises a processor 31 connected to the radar sensor 21, said processor 31 being configured to determine the amount of liquid in said container 13; 13' based on the detected position of the liquid surface and based on pre-stored container shape information. By distributing intelligence to the sensor device, communication from the sensor device to an external control system is less complex and more robust, i.e. less capacitance is required and smaller, cheaper cables can be used for that communication.

[0040] Suitably, the sensor arrangement 1;1' further comprises a connection device 51 by which the radar sensor 21, processor 31 and angle sensor 25' can be connected to a control system 111 in a benchtop fluid handling system 101 in which the vessel 13;13' and sensor arrangement 1;1' are used. The connection device 51 can be connected to the control system 111 by wire or wirelessly.

[0041] The sensor device 1;1' according to the present invention is suitably configured to be mounted in a vessel 13;13' having a height of 10-100 cm and / or a volume of 0.5-220 liters or 0.5-20 liters, for example, so that it can be used in a chromatography system or another bench-top fluid handling system.

[0042] According to the invention there is also provided a method for detecting the position of a liquid surface in a container 13; 13' used for storing liquid in a bench-top fluid handling system 101. The method is illustrated in the flow chart of Figure 6. The method steps will be briefly described in the following order with reference to Figure 6:

[0043] S1: Attaching the container attachment part 23;23' of the above-defined sensor device 1;1' according to the present invention to the top opening 11;11' of the container 13;13'.

[0044] S2: If the sensor device 1;1′ comprises a tube holder portion 33, positioning one or more tubes 41 provided in the container 13;13′ in such tube holder portion 33 of the sensor device 1;1′. This is thereby an optional step.

[0045] S3: Rotating the tube holder part 33 relative to the container mounting part 23;23′ so that the tubing 41 provided on the tube holder part 33 is oriented for convenient connection in the benchtop fluid handling system 101. This is an optional step that is only performed if the sensor device 1;1′ comprises a tube holder part 33 connected to the sensor device 1;1′ so that it can be rotated.

[0046] In some embodiments of the present invention, the sensor housing 24 may be provided in at least two different positions relative to the container mount 23; 23' as described above. In these embodiments, the method includes the following steps S4 and S6.

[0047] S4: Positioning the sensor housing 24 of the sensor device 1;1' in a closed position relative to the container mounting portion 23;23' to measure the liquid level in the container 13;13'. The closed position is a position where the sensor housing 24 covers at least a part of the upper opening 11;11' of the container 13;13', and the radar sensor 21 is in an operating position when the sensor housing 24 is in the closed position.

[0048] S5: When the radar sensor 21 is in the operating position, detecting the position of the liquid surface in the container 13; 13'.

[0049] S6: Positioning the sensor housing 24 of the sensor device 1;1' in an open position relative to the container mounting portion 23;23' in order to refill liquid into the container 13;13', the open position being a position in which the sensor housing 24 does not cover the upper opening 11;11'.

[0050] The method further comprises the optional steps of: S7: Measuring the tilt angle of the sensor housing 24 by the angle sensor 25' mounted on the sensor housing 24. The tilt angle can be used both to indicate whether the sensor housing 24 is in a closed or open position and to indicate whether the container is tilted, which may be a problem. A warning may be provided to the user that the container may be tilted.

[0051] S8: Indicating whether the radar sensor 21 is in an operating position by the position indicating device 25. The position indicating device 25 can be the angle sensor 25' described above in some embodiments.

[0052] The measured tilt angle of the sensor housing 24 can be used to detect tilt of the entire container 13;13' and inversion of the sensor housing 24, i.e., whether the sensor housing 24 is in the open or closed position, for example, to fill the container with new liquid. Various ranges of tilt angles may be preset in the sensor housing 24 or the processor 31 of the control system 111, such as one range in which the sensor housing 24 is detected as being in the open position and one range in which the sensor housing 24 is detected as being in the closed position. Another range of tilt angles can be set, and another range may indicate that the entire container has been inadvertently tilted. In such cases, sensor measurements may be disturbed, and the user may be alerted, for example, by an audio or displayed message. If the entire container 13;13' is tilted, liquid level detection may be inaccurate or even non-functional, and the user may be asked to verify that the container 13;13' is correctly positioned. If the tilt angle is outside the predetermined tilt angle range for the closed position, the user may also be asked to verify that the sensor housing 24 is in the correct closed position. Another preset tilt angle range may be a range in which the most likely reason for tilting is that the user is trying to use the last of the liquid in the container by tilting it, in which case the pump can be operated even if the radar sensor 21 cannot measure the liquid level.

[0053] When the sensor housing 24 is detected to be in the open position, e.g., to refill the container with new liquid, the pump 113 in the system 101 can proceed to pump the liquid appropriately. During this time, pump metrics can be used to measure the volume of liquid in the container, i.e., dead reckoning is used instead of radar sensor level detection while the sensor housing 24 is in the open position. As soon as the sensor housing 24 is inverted back to the closed position, the radar sensor 21 begins measuring again, and the position of the liquid surface in the container is updated accordingly.

[0054] The materials used for the sensor device 1;1' must be suitable for use with the chemicals used in the processes performed within the system 101. Additionally, the sensor housing 24 containing the radar sensor must be made from a material that allows the radar sensor to transmit and receive electromagnetic waves. Suitable materials may include, for example, PEEK (Polyether Ether Katone) or PPS (Polyphenylene Sulfide) or PP (Polypropylene).

Claims

1. 1. A sensor device (1; 1′) configured to be attached to a top opening (11; 11′) of a container (13; 13′) used to store a liquid in a bench-top fluid handling system (101), comprising: A millimeter wave radar sensor (21); a sensor housing (24) including the millimeter wave radar sensor (21); a container mounting portion (23; 23') connected to the sensor housing (24) and configured to mount the sensor device (1; 1') on the top opening (11; 11') of the container (13; 13') so that the millimeter wave radar sensor (21) can be placed in an operational position for detecting the position of a liquid surface in the container (13; 13'); A sensor device (1; 1') comprising:

2. 2. The sensor device (1; 1') of claim 1, wherein the sensor housing (24) can be positioned in at least two different positions relative to the container mounting portion (23; 23'), one of the positions being a closed position in which the sensor housing (24) covers at least a portion of the top opening (11; 11') of the container (13; 13'), and another position being an open position in which the sensor housing (24) does not cover the top opening (11; 11'), and the millimeter-wave radar sensor (21) is positioned in the operating position when the sensor housing (24) is positioned in the closed position.

3. 3. The sensor device (1; 1') of claim 2, wherein the sensor housing (24) is connected to the sensor device (1; 1') by a hinge (27), and the hinge (27) allows the sensor housing (24) to be flipped from the closed position to the open position, allowing access to the top opening (11; 11') of the container (13; 13').

4. Sensor device (1; 1') according to claim 2 or 3, wherein the sensor housing (24) comprises an angle sensor (25').

5. 10. The sensor arrangement (1; 1') according to any one of the preceding claims, further comprising a position indicating device (25) configured to indicate whether the millimeter wave radar sensor (21) is in the operating position.

6. 10. The sensor device (1; 1') of claim 1, further comprising a tube holder portion (33) that can be attached to the container mounting portion (23; 23') and that is configured to hold a tube (41) provided in the container (13; 13') toward one side of the top opening (11; 11').

7. The sensor device (1; 1') of claim 6, wherein the tube holder portion (33) has a rail (34) extending from the upper opening (11; 11') of the container (13; 13') into the container and out of the container when the sensor device (1; 1') is installed in the container, and the rail (34) can support one or more tubes (41) installed in the container.

8. 3. The sensor device (1; 1') of claim 7, wherein the tube holder portion (33) further comprises a ring-shaped fixing portion (35) connected to the rail (34), the ring-shaped fixing portion being arranged between the container mounting portion (23; 23') and the sensor housing (24) when the sensor housing is arranged in the closed position, whereby the ring-shaped fixing portion (35) is connected to the container mounting portion (23; 23') so as to be rotatable relative to the container mounting portion (23; 23'), and is also connected to the sensor housing (24) so ​​that the housing portion (24) can be arranged in at least two different positions relative to the container mounting portion (23; 23'), wherein the two positions include the open position and the closed position.

9. 10. The sensor device (1; 1') of any one of the preceding claims, wherein the sensor device comprises a processor (31) connected to the radar sensor (21), the processor (31) being configured to determine the amount of liquid in the container (13; 13') based on the detected position of the liquid surface and based on pre-stored container shape information.

10. 10. The sensor device (1; 1') according to any one of the preceding claims, wherein the container mounting portion (23; 23') comprises a thread for a threaded connection to a top opening (11') of a container (13) that is provided with a thread, or comprises a magnet for a magnetic connection to a top opening (11') of a container (13').

11. 10. The sensor arrangement (1; 1') according to any one of the preceding claims, further comprising a connection device (51) by means of which the radar sensor (21) and possibly a processor (31) and / or an angle sensor (25) can be connected to the vessel (13; 13') and to a control system (111) in the bench-top fluid handling system (101) in which the sensor arrangement (1; 1') is used.

12. The sensor device (1; 1') according to any one of the preceding claims, wherein the sensor device is adapted to be attached to a container (13; 13') having a height of 10 to 100 cm and / or a volume of 0.5 to 20 liters.

13. 1. A method for detecting the position of a liquid surface in a container (13; 13') used to store a liquid in a bench-top fluid handling system (101), comprising: Attaching (S1) a container attachment part (23; 23') of a sensor device (1; 1') according to any one of the preceding claims to an upper opening (11; 11') of said container (13; 13'); Detecting (S5) the position of the liquid surface in the container (13; 13') when the millimeter wave radar sensor (21) is in the operating position; A method comprising:

14. Positioning (S2) one or more tubes (41) provided in the container (13; 13') in the tube holder portion (33) of the sensor device (1; 1').

14. The method of claim 13, further comprising:

15. rotating (S3) the tube holder portion (33) relative to the container mounting portion (23; 23') so that the tubing (41) mounted on the tube holder portion (33) is oriented for convenient connection in the bench-top fluid handling system (101); 15. The method of claim 14, further comprising:

16. Indicating whether the radar sensor (21) is in the operating position by a position indicating device (25) (S8). The method of any one of claims 13 to 15, further comprising:

17. 17. The method of claim 16, wherein indicating (S8) by the position indicating device (25) whether the radar sensor (21) is in the operating position includes measuring an inclination angle of the sensor housing (24), and the position indicating device (25) comprises an angle sensor (25') provided on the sensor housing (24).

18. positioning (S4) a sensor housing (24) of the sensor device (1; 1') in a closed position relative to the container mounting portion (23; 23') to detect a liquid level in the container (13; 13'), the closed position being a position where the sensor housing (24) covers at least a part of the upper opening (11; 11') of the container (13; 13'), and the radar sensor (21) is located in the operating position when the sensor housing (24) is located in the closed position; positioning (S6) the sensor housing (24) of the sensor device (1; 1') in an open position relative to the container mounting portion (23; 23') in order to refill the container (13; 13') with liquid, the open position being a position in which the sensor housing (24) does not cover the upper opening (11; 11'); and The method of any one of claims 13 to 17, further comprising:

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