Metering device for metering a liquid

Abstract

The invention relates to a metering device (1; 51) for metering a liquid, comprising a pressure chamber (2) in which a flexible storage container (3) is accommodated; a fluid pump (4) which is designed to influence a working pressure in the pressure chamber (2); a metering channel (5) which is connected in a fluidically communicative manner to the storage container (3) and which is guided out of the pressure chamber (2); a working pressure sensor (6) which is designed to determine the working pressure in the pressure chamber (2); and a control device (7) which is electrically connected to the fluid pump (4) and the working pressure sensor (6) and which is designed to evaluate sensor signals of the working pressure sensor (6) and to control the fluid pump (4).

Description

[0001]

[0002] December 17, 2025

[0003] Festo 5E & Co. KG, Ruiter Straße 82, 73734 Esslingen

[0004] Dosing device for dispensing a liquid

[0005] The invention relates to a dosing device for dosing a liquid.

[0006] EP 2 919 016 Bl discloses a disposable dispenser unit with a fluid reservoir comprising a pouch or bottle with an opening, a label for storing information, a dispenser head formed by a pump chamber which is fluidly connected to at least one injector nozzle via an outlet, and a device arranged on the dispenser head for attaching the disposable dispenser unit to a diagnostic system, wherein the dispenser head is fluidically connected to the fluid reservoir via an inlet of the pump chamber, wherein the pump chamber comprises a piston which is hollow and has at least two openings and encloses a volume which can be filled with fluid so that the fluid to be dispensed flows through the piston to the injector nozzle, wherein the pump chamber has an inlet valve and an outlet valve which are arranged at the outlet of the pump chamber, and the piston has the inlet valve in one of the openings.wherein the fluid reservoir is arranged above the pump chamber, wherein the disposable dispenser unit further comprises a fluid sensor for detecting a fluid within the fluid reservoir, wherein the fluid sensor is located below the opening of the pouch or bottle, between the,

[0007] P 35635 / PCT

[0008] December 17, 2025 Opening and the pump chamber and is located near the opening.

[0009] The object of the invention is to provide a dosing device with an expanded range of functions.

[0010] This task is solved with a metering device for dispensing a liquid, which has the following features: a pressure chamber in which a flexible reservoir is accommodated, a fluid source designed to influence a working pressure in the pressure chamber, a metering channel that is fluidically connected to the reservoir and that leads out of the pressure chamber, a working pressure sensor designed to determine the working pressure in the pressure chamber, and a control device that is electrically connected to the working pressure sensor and designed to evaluate sensor signals from the working pressure sensor.

[0011] The dosing device operates on the principle that a flexible reservoir, filled with a liquid to be dispensed by the device, can be externally pressurized to cause liquid to be dispensed. With a suitable design of the fluid source, the flexible reservoir can be pressurized either positively or negatively to selectively dispense liquid or draw liquid into it. To achieve this positive or positive and negative pressure on the flexible reservoir, it is housed in a pressure chamber with a significantly lower deformation capacity than the reservoir itself. This allows for a

[0012] P 35635 / PCT

[0013] December 17, 2025. The working volume, limited by the pressure chamber and reduced by the volume of the flexible reservoir, is to be pressurized for dispensing liquid from the flexible reservoir and, if necessary, pressurized for drawing liquid into the flexible reservoir. Pressurization occurs when the working pressure in the pressure chamber's working volume is greater than the ambient pressure for the metering device. Negative pressure occurs when the working pressure in the pressure chamber's working volume is less than the ambient pressure for the metering device.Preferably, the pressure chamber is designed and constructed in such a way that it does not undergo plastic deformation during normal use of the metering device, and that any elastic deformation during normal use results only in a minor change in the volume of the pressure chamber. It is particularly preferred that the pressure chamber does not experience any increase or decrease in volume exceeding 5 percent of its volume during normal use.

[0014] The flexible storage container can, for example, be made of a rubber-elastic material. It is advantageous if the maximum volume of the flexible storage container corresponds to the maximum amount of liquid it is intended to hold. This prevents the rubber-elastic material from deforming elastically when the flexible storage container is filled to its maximum capacity, which could lead to an internal pressure in the container that exceeds the ambient pressure for the dosing device. Such an internal pressure could cause...

[0015] P 35635 / PCT

[0016] December 17, 2025, contribute to questioning the precise dosage that is being pursued with the help of the dosing device.

[0017] Preferably, the flexible storage container is designed as a film bag produced by a material-bonded connection of at least two film layers. This material-bonded connection can be achieved, for example, through an adhesive bonding process or a heat-based film welding process. Consistent with the flexible storage container being made of a rubber-elastic material, it is preferably provided that the maximum volume of the flexible storage container corresponds to the maximum amount of liquid that is to be held in the flexible storage container.

[0018] For example, it is envisaged that the liquid to be dosed is filled into a flexible storage container via a filling nozzle formed on the container, in a filling system where, for instance, a predetermined level of sterility is maintained, without any air or other gas content. The filling nozzle may be sealed and, if necessary, disconnected after the filling process is complete. The filled flexible storage container is then inserted into the pressure chamber. For example, the dosing channel may pierce the flexible storage container, thereby establishing a fluidic connection between the volume of the flexible storage container, the dosing channel, and the surroundings of the dosing device. Alternatively, the liquid to be dosed may be drawn into a flexible storage container.For this purpose, an empty flexible storage container is placed in the pressure chamber and brought into fluidic communication with the dosing channel. Then.

[0019] P 35635 / PCT

[0020] On December 17, 2025, it may be possible to fill the pressure chamber with a positive working pressure to achieve the most complete possible emptying of the flexible reservoir. In a subsequent step, the section of the dosing channel located outside the pressure chamber, or a pipetting tip attached to this section, is immersed in a liquid, and a vacuum is applied to the pressure chamber to draw liquid into the flexible reservoir. In contrast to a separately filled flexible reservoir, as described above, a certain residual volume of gas must be accepted, which remains in the flexible reservoir after the suction process is complete.

[0021] In any case, the flexible reservoir ensures separation between the liquid to be dosed and the gas, especially air, that causes a pressure change in the working space of the pressure chamber. This prevents, in particular, any unwanted mixing between the gas and the liquid to be dosed, which could potentially lead to chemical reactions and / or contamination of the liquid being dosed.

[0022] The flexible storage container is fluidically connected to a metering channel that extends through a wall section of the pressure chamber into the vicinity of the metering device. Accordingly, during normal use of the metering device, a first opening of the metering channel, which is preferably tubular, is located in the flexible storage container, while a second opening of the metering channel is located outside the pressure chamber. Preferably, the metering channel is connected at the second opening to a

[0023] P 35635 / PCT

[0024] December 17, 2025. The device is equipped with a coupling that enables a fluid-tight connection of a pipetting tip. With such a pipetting tip, particularly one made of plastic, advantageous liquid dispensing can be achieved, for example, into test tubes. The pipetting tip is usually conically tapered, thus enabling advantageous droplet formation, which is beneficial for highly accurate dispensing of small quantities of liquid. Alternatively, it can be provided that liquid exits directly from the second opening of the dispensing channel without the need for an additional pipetting tip.

[0025] To enable precise liquid dosing, a working pressure sensor is assigned to the pressure chamber, designed to determine the working pressure within the chamber. For this purpose, the working pressure sensor can be located directly within the working volume of the pressure chamber and provide a pressure-dependent sensor signal via electrical leads connected to a control device. Alternatively, the working pressure sensor can be located on an outer surface of the pressure chamber and fluidically connected to the working volume via a measuring bore that penetrates a section of the chamber wall. In this case as well, an electrical lead is provided to connect the working pressure sensor to the control device.

[0026] The control device preferably comprises a microprocessor running a computer program designed to evaluate sensor signals from the working pressure sensor. Optionally, the microprocessor can also be configured to provide control signals to an electrical output stage, which is also part of the

[0027] P 35635 / PCT

[0028] December 17, 2025. The control device can be designed as follows: The task of the electrical output stage is to supply electrical energy to an electrical consumer, such as a fluid pump, depending on the control signals from the microprocessor. In principle, the control device can be designed to operate completely autonomously, for example, by dosing liquid at a predetermined interval.Typically, the control device is provided with a communication interface through which dosing signals are supplied by a separately designed dosing switch, which can be manually operated by an operator, or by a higher-level control system such as a programmable logic controller, which can cause the control device to perform a dispensing operation or, if applicable, a sequence of a suction operation and a dispensing operation for liquid.

[0029] Advantageous further developments of the invention are the subject of the dependent claims.

[0030] It is advantageous if the flexible storage container has a dimensionally stable interface area designed for a fluid-tight connection with the dispensing channel. The interface area can be an integral part of the flexible storage container. This is achieved, for example, by designing the interface area as a plastic component that is welded to the film layers of the flexible storage container. The interface area facilitates handling the flexible storage container with regard to establishing the fluid-contact connection to the dispensing channel. The interface area can have a bore for receiving the dispensing channel, which is preferably tubular.

[0031] P 35635 / PCT

[0032] December 17, 2025, which is sealed with a thin-walled membrane, this membrane being pierced when the flexible reservoir is placed onto the dosing channel with the interface area. Alternatively, the interface area can have a valve that opens when the flexible reservoir is placed onto the dosing channel with the interface area and closes again when the flexible reservoir is removed from the dosing channel. Additionally, the bore for receiving the dosing channel can be provided with one or more seals, for example O-rings, which ensure a fluid-tight connection with the dosing channel.

[0033] In a further development of the invention, a flow sensor is assigned to the metering channel, which is designed to determine the quantity of liquid flowing through the metering channel. Various measuring principles can be used for a flow sensor that enables the determination of a volumetric or mass flow rate of a liquid through the metering channel. Since the metering device is already equipped with a control device, measuring principles that operate with electrically driven sensors are particularly suitable. In addition to magnetic inductive flow measurement and ultrasound-based flow measurement, flow measurement based on acoustic harmonics (SAW - surface acoustic waves) or Coriolis forces can also be provided.Preferably, the flow sensor enables precise volumetric or mass flow rate determination, independent of the liquid flow direction in the metering channel. The flow sensor signals are processed in the control device in addition to the operating pressure signals from the operating pressure sensor and can be used, for example, to control the fluid pump.

[0034] P 35635 / PCT

[0035] December 17, 2025. Preferably, the flow sensor comprises a first liquid pressure sensor associated with a first metering channel section adjacent to the flexible reservoir, and a second liquid pressure sensor associated with a second metering channel section extending between the first metering channel section and an outlet opening of the metering channel. Such a flow sensor is based on differential pressure measurement, with the differential pressure being determined between a first measuring point located on a first metering channel section and a second measuring point located on a second metering channel section. The first measuring point is located in the immediate vicinity of the flexible reservoir, while the second measuring point is located away from the flexible reservoir, in particular adjacent to the outlet opening of the metering channel.For a flow sensor designed in this way to function properly, it is necessary that the control device, which is electrically connected to the first liquid pressure sensor and the second liquid pressure sensor, contains a table of values ​​or a characteristic map from which a unique relationship between a pressure difference between the two measuring points and a volume flow or mass flow through the metering channel can be derived.

[0036] In a further embodiment of the invention, a throttle, particularly a static one, is arranged in the metering channel between the first liquid pressure sensor and the second liquid pressure sensor. The purpose of the throttle is to provide a defined flow resistance for the liquid flowing through the metering channel during a liquid dispensing process and / or during a liquid intake process. It is preferably provided that in P 35635 / PCT

[0037] December 17, 2025. The control device stores a characteristic map from which a unique volumetric or mass flow rate for the liquid can be derived for different pressure differences between the first and second measuring points. The determined volumetric or mass flow rate can then be used, for example, to control the fluid pump, which has either a direct or indirect influence on the intake or discharge of liquid into or from the flexible storage tank.

[0038] It is advantageous if the fluid source is designed as a fluid pump for the controlled or regulated supply of overpressure, or for the controlled or regulated supply of both overpressure and underpressure to the pressure chamber. If the fluid pump is designed solely for the controlled or regulated supply of overpressure, it can be used to discharge liquid from the flexible reservoir. If the fluid pump is designed for both the controlled or regulated supply of overpressure and the controlled or regulated supply of underpressure, it can be used both to discharge liquid from the flexible reservoir and to draw liquid into the flexible reservoir.The fluid pump can, for example, be configured to supply both positive pressure and negative pressure to the pressure chamber, each in a controlled manner. For instance, a timer can be used for supplying positive pressure and negative pressure to the pressure chamber. Alternatively, pressure control based on sensor signals from the working pressure sensor can be used for supplying P 35635 / PCT.

[0039] December 17, 2025, is intended for the provision of overpressure and / or underpressure to the pressure chamber, thereby ensuring advantageous precision for the respective liquid delivery or liquid intake process.

[0040] Preferably, the fluid pump can be electrically operated. The electrical energy required for this is supplied by the control device, which is electrically connected to the fluid pump. Preferably, the control device controls the fluid pump with electrical energy depending on sensor signals from the working pressure sensor.

[0041] It is advantageous for the fluid pump to have a pump chamber with an electrically variable wall section made of a piezoelectric material. Such a fluid pump is characterized by low energy consumption, a minimal number of wear parts, and a compact design, and is also referred to as a piezo pump. For example, a wall section of the pump chamber is defined by a piezoelectric element whose spatial extent changes when an electrical voltage is applied, thereby increasing or decreasing the volume of the pump chamber.

[0042] In an alternative embodiment of the invention, the fluid source is formed by a central compressed air network, and a pressure-regulating proportional valve is arranged between the fluid source and the pressure chamber, which is electrically connected to the control device. The central compressed air network can be supplied with compressed air by a central compressed air pump, in particular a compressor.

[0043] P 35635 / PCT

[0044] December 17, 2025, and extend extensively throughout a building. The central compressed air network can also be designed solely for the central supply of multiple compressed air consumers in a single room. The compressed air supplied by the central compressed air network is delivered to the pressure chamber using a pressure-regulating proportional valve. The pressure-regulating proportional valve can be set either manually or electrically to a fluid pressure to be supplied to the pressure chamber and ensures that this fluid pressure is maintained. The fluid pressure supplied by the compressed air network can, for example, be converted into a negative pressure via a Venturi nozzle arrangement, which can then be supplied to the pressure chamber as an alternative to positive pressure. A connection to the control device is provided for the electrical supply of the pressure-regulating proportional valve.If necessary, the pressure regulating proportional valve is electrically controlled by the control device.

[0045] Preferably, a metering valve is associated with the metering channel. This valve is designed to block or release the metering channel and is electrically connected to the control device, which is configured to actuate the metering valve. The metering valve allows a liquid dispensing process and a liquid intake process to be terminated even if a pressure differential still exists between the pressure chamber and the surrounding environment of the metering device. For example, the metering valve is a media-separated 2 / 2-way valve with a solenoid or piezoelectric actuator. The metering valve can be actuated either open-loop or closed-loop, with the control or regulation being implemented, for example, on the

[0046] P 35635 / PCT

[0047] December 17, 2025. This can be based on the pressure signal of the working pressure sensor or a volume flow or mass flow rate of a flow sensor.

[0048] In a further embodiment of the invention, a supply valve is associated with a supply line extending between the fluid pump and the pressure chamber. The supply valve is designed to block or release a fluidically communicating connection between the fluid pump and the pressure chamber. The supply valve is electrically connected to the control device, and the control device is designed to actuate the supply valve. Blocking the fluidically communicating connection between the pressure chamber and the fluid pump can be particularly advantageous if, due to the design principle of the fluid pump, an outflow of the working gas, especially ambient air, which can be pumped into the pressure chamber by the fluid pump, occurs while the fluid pump is not in operation.Furthermore, by blocking the fluidic connection between the pressure chamber and the fluid pump at the beginning of a pumping cycle, a pressure build-up in the fluid pump can be waited for before the fluidic connection to the pressure chamber is released. The supply valve can be designed, for example, as a solenoid valve or as a piezoelectric valve, preferably as a 2 / 2-way valve, and in particular as a proportional valve.

[0049] Preferably, a supply pressure sensor is assigned to the supply line. This sensor is designed to determine the supply pressure in the supply line and is connected to the control device, which is designed to evaluate sensor signals from the supply pressure sensor and to control the fluid pump in a regulated manner. The supply pressure sensor provides a pressure signal which

[0050] P 35635 / PCT

[0051] December 17, 2025 directly related to the function of the fluid pump, thus enabling precise and efficient control of the fluid pump.

[0052] In a further embodiment of the invention, a supply valve is provided for the supply line, arranged between the fluid pump and the supply valve, and is connected to the control device designed to actuate the supply valve. The supply valve is designed in the same way as the supply valve for blocking or releasing the supply line, wherein a section of the supply line extending between the supply valve and the supply valve can be used as a fluid reservoir with a defined storage volume in order to enable the provision of overpressure or underpressure to the pressure chamber independently of the current operation of the fluid pump.For example, the storage volume of the section of the supply line extending between the feed valve and the supply valve corresponds to a fluid volume that is typically to be dispensed by the metering device. In this case, for instance, the fluid pump can be configured to pressurize the section of the supply line with the supply valve closed and the feed valve open, and then the feed valve can be moved to the blocking position. In a subsequent step, the supply valve can then be opened to equalize the pressure between the section of the supply line and the pressure chamber, thereby increasing the working pressure in the pressure chamber. This allows fluid to be metered from the flexible reservoir through the metering channel into the vicinity of the metering device.

[0053] P 35635 / PCT

[0054] December 17, 2025. Advantageous embodiments of the invention are shown in the drawing. This shows:

[0055] Figure 1 is a strictly schematic, partially cutaway representation of a first embodiment of a dosing device, and

[0056] Figure 2 is a strictly schematic, partially cutaway representation of a second embodiment of a dosing device.

[0057] A first embodiment of a dosing device 1, shown in Figure 1, serves to dispense a liquid and is intended, for example, for use in laboratories, particularly in life sciences. The dosing device 1 can dispense a liquid drop by drop, with a drop volume of less than 1 microliter, preferably less than 100 nanoliters.

[0058] The dosing device 1 is intended, in particular, for use in a laboratory system (not shown) used for the automated processing of chemical or biological samples, in which the dosing device 1 is used to dispense a reagent liquid or an analytical liquid into a plurality of sample containers. By way of example, the laboratory system may be able to move the dosing device 1 in at least one spatial direction, preferably in at least two spatial directions, and in particular in at least three spatial directions, in order to enable, for example, the positioning of the dosing device 1 above each sample container from a plurality of sample containers, which are in particular arranged in a predetermined grid.

[0059] P 35635 / PCT

[0060] December 17, 2025. The dosing device 1 comprises as essential components a pressure chamber 2, a flexible storage container 3, a pressure-regulating proportional valve 16 connected to a fluid source 4, a working pressure sensor 6, and a control device 7, and is already configured in this configuration for dosing liquids. Furthermore, the dosing device 1 is equipped, purely by way of example, with additional components described in more detail below, with which additional functions for liquid dosing can be implemented.

[0061] The pressure chamber 2, which can also be described as a closed container, encloses a working volume 13 that is sealed off from the surroundings of the metering device 1. In the schematic representation of Figure 1, the pressure chamber 2 is shown as a single piece; in practice, the pressure chamber 2 is designed in multiple parts to allow access to the working volume 13.

[0062] In pressure chamber 2, a flexible storage container 3, represented purely as an example by a closed bag made of plastic film, is housed. The flexible storage container 3 is filled with a liquid 14, which can be dispensed into the environment by the metering device 1 in the manner described in more detail below. For this purpose, a pipe section 15 of a metering channel 5 projects into the flexible storage container 3, the metering channel 5 passing through both the flexible storage container 3 and the pressure chamber 2 and extending, with a coupling sleeve 12 connected to the pipe section 15, into the vicinity of the metering device 1. This establishes a fluidically communicating connection between a first opening 17 of the metering channel 5 formed at the end of the pipe section 15 and a coupling sleeve 12 connected to the pipe section 15.

[0063] P 35635 / PCT

[0064] On December 17, 2025, a second opening 18 of the metering channel 5 was created on the coupling sleeve 12 of the metering channel 5.

[0065] For example, the first opening 17 of the metering channel 5 is inclined relative to a longitudinal axis 30 of the metering channel 5 and thus forms a cutting area 20. This cutting area is designed to cut a sealing membrane (not shown) in a dimensionally stable interface area 19 of the flexible storage container 3. This membrane first closes a bore 21 of the interface area 19 before the flexible storage container 3 is inserted into the pressure chamber 2. For example, the interface area 19 is designed as a plastic strip that is bonded, in particular welded, to a film sleeve 31 of the flexible storage container 3. For example, the film sleeve 31 can be manufactured as a bag open at one end and is then welded to the interface area 19 to define a closed volume in which the liquid 14 can be contained.

[0066] Starting from pressure chamber 2, the pipe section 15 of the metering channel 5 extends through the pressure chamber 2 and passes through a channel bushing 10, which is sealed to the pressure chamber 2 by a sealing ring 11. An end region of the pipe section 15 facing away from the pressure chamber 2 opens into the coupling sleeve 12, which is also part of the metering channel 5. The coupling sleeve 12 is shown partially in section and is designed to receive components described in more detail below, which are only symbolically depicted in Figure 1. A pipetting tip coupling 28 is formed at an end region of the coupling sleeve 12 facing away from the pipe section 15, which also defines the second opening 18. This coupling ensures a positive-locking connection.

[0067] P 35635 / PCT

[0068] December 17, 2025 Coupling of a pipetting tip 29, shown only with a dashed line, is planned.

[0069] The control device 7, shown only schematically, is connected to the pressure-regulating proportional valve 16 via an electrical control line 8 and can supply electrical energy to the pressure-regulating proportional valve 16 via the control line 8 and, if necessary, actuate the pressure-regulating proportional valve 16. The pressure-regulating proportional valve 16 supplies the compressed air provided by the fluid source 4 to a supply line 32, which is fluidically connected to a working volume 13 that is bounded by the pressure chamber 2 and the flexible reservoir 3, particularly depending on electrical actuation by the control device 7.

[0070] Furthermore, the control device 7 is connected to the working pressure sensor 6 via a sensor line 9, the control device 7 being configured to supply electrical energy to the working pressure sensor 6. The working pressure sensor 6 is also configured to supply pressure-dependent sensor signals to the control device 7. The working pressure sensor 6 is in fluid communication with the working volume 13 via a pressure line 35 and is configured to determine the pressure in the working volume 13 and convert it into an electrical sensor signal.

[0071] For example, a metering valve 36 is assigned to the metering channel 5 in the area of ​​the coupling sleeve 12. This valve is, purely by way of example, a 2 / 2 solenoid valve, which is electrically connected to the control device 7 via a metering valve line 37. With the aid of the

[0072] P 35635 / PCT

[0073] December 17, 2025. The metering valve 36 can block a fluid flow passing through the metering channel 5. The metering valve 36 is not strictly necessary for the operation of the metering device 1 and can be used additionally to improve the liquid metering that is to be enabled by the metering device 1.

[0074] An optional flow sensor 22 is mounted between the optional metering valve 36 and the pipette tip coupling 28. This sensor, like the metering valve 36, serves to further improve the metering accuracy of the metering device 1. By way of example, the flow sensor 22 comprises a first liquid pressure sensor 23 and a second liquid pressure sensor 24 arranged at a distance from the first liquid pressure sensor 23, each electrically connected to the control device 7 via associated sensor lines 25, 26. A throttle 27 is arranged between the first liquid pressure sensor 23 and the second liquid pressure sensor 24, configured to provide a defined flow resistance for liquid flowing through the metering channel 5.For determining a volume flow rate or a mass flow rate of the liquid flowing through the metering channel 5, the control device 7, which is essentially a microprocessor with associated peripherals and a storage device, is provided with a table of values ​​or a characteristic map from which an associated volume flow rate or mass flow rate can be determined for a given pressure difference between the first liquid pressure sensor 23 and the second liquid pressure sensor 24.

[0075] For the second embodiment of a metering device 51 shown in Figure 2, the same reference numerals are used for functionally identical components as for the

[0076] P 35635 / PCT

[0077] December 17, 2025. Metering device 1 is used. In contrast to metering device 1, metering device 51 does not have a metering valve. Furthermore, in metering device 51, a supply valve 33 and a feed valve 38 as well as a supply pressure sensor 40 are provided in the supply line 32 at the location of the pressure regulating proportional valve 16. In addition, in the second embodiment of metering device 51, an electrically operated fluid pump 54 is provided at the location of the fluid source 4, which is electrically connected to the control device 7 via a control line 58.

[0078] The supply valve 33 is, purely as an example, a 2 / 2 solenoid valve which is electrically connected to the control device 7 via a supply valve line 34.

[0079] The supply valve 38 is designed purely as an example of a 2 / 2 solenoid valve and is electrically connected to the control device 7 via a supply valve line 39. The supply pressure sensor 40, which is fluidically arranged between the supply valve 38 and the supply valve 33, is electrically connected to the control device 7 via a supply pressure sensor line 41. A section of the supply line 32 can be isolated from both the fluid pump 4 and the working chamber 13 using the supply valve 38 and the supply valve 33, and used for the intermediate storage of a supply volume. This supply volume can be made available to the working chamber 13 at a given time by actuating the supply valve 33, thereby causing a slight pressure increase in the working chamber and thus a discharge of liquid through the metering channel 5 into the vicinity of the metering device 1.

[0080] P 35635 / PCT

[0081] December 17, 2025. The operation of the dosing device 1, which in a basic configuration comprises the pressure chamber 2, the flexible reservoir 3, the pressure-regulating proportional valve 16, the dosing channel 5, the working pressure sensor 6, and the control device 7, can be described as follows: In a first step, the flexible reservoir 3, filled with liquid 14 and sealed, is inserted into the open pressure chamber 2. The dimensionally stable, formed interface area 19 of the flexible reservoir 3 is placed onto the pipe section 15 of the dosing channel 5 such that the pipe section 15 passes through the bore 21 in the interface area 19.Here, the cutting area 20, which is formed at the end of the pipe section 15, cuts open a sealing membrane (not shown) of the interface area 19, so that a fluidically communicating connection exists between the interior of the flexible reservoir 3 and the metering channel 5. The pressure chamber 2 is then closed, allowing the working volume 13 to be pressurized. To prevent unwanted leakage of liquid through the metering channel 5 during the assembly of the flexible reservoir 3 in the pressure chamber 2, a sealing cap (not shown) can be attached to the pipette tip coupling 28 beforehand. This cap can be replaced with a pipette tip 29 once the assembly process is complete.For a subsequent dosing process, the pressure-regulating proportional valve 16 is actuated by the control device 7, so that compressed air, supplied by the fluid source 4, is pumped into the working volume 13 of the pressure chamber 2. This pressure increase in the working volume 13 causes liquid 14 to be pumped from the flexible reservoir 3 through the dosing channel 5 to the pipetting tip 29 and from there.

[0082] P 35635 / PCT

[0083] On December 17, 2025, the pressure was released into the environment. The pressure increase in the working volume 13 leads to a change in the sensor signal provided by the working pressure sensor 6 to the control device 7, thereby enabling a check of the working pressure provided by the pressure-regulating proportional valve 16 in the working volume 13. If necessary, the control device 7 may adjust the setpoint working pressure set at the pressure-regulating proportional valve 16. To end each dosing process, a reduction in the working pressure in the working volume 13 is provided, which is effected by a corresponding actuation of the pressure-regulating proportional valve 16 by the control device 7, whereby this actuation results in the venting of the working volume 13.

[0084] If higher dosing precision is required, the basic configuration of the dosing device 1 described above can be equipped with the flow sensor 22 and / or the dosing valve 36. The flow sensor 22 enables precise determination of the actual volumetric or mass flow rate of liquid flowing through the dosing channel 5. For this purpose, the sensor signals from the first liquid pressure sensor 23 and the second liquid pressure sensor 24 are evaluated in the control device 7 to determine the respective liquid volumetric or mass flow rate, taking into account the characteristics of the throttle 27. The dosing valve 36, provided as an alternative to or in addition to the flow sensor 22, enables precise opening and closing of the dosing channel 5 and can thus contribute to improved dosing accuracy.

[0085] The dosing device 51 according to Figure 2 includes a supply valve 33, a feed valve 38 and a

[0086] P 35635 / PCT

[0087] December 17, 2025. Supply pressure sensor 40 is provided. By using the combination of supply valve 33, feed valve 38, and supply pressure sensor 40, a storage volume upstream of the working volume 13, for example for compressed air, can be implemented. This storage volume, which allows for the storage of a volume of compressed air corresponding, for example, to a typical quantity of air required for dosing a typical quantity of liquid, enables a renewed pressure build-up in the storage volume during a dosing process. This pressure build-up occurs after the supply valve 33 has been closed, the feed valve 38 has been opened, and the fluid pump 4 has been activated. This ensures that the compressed air volume is already available for the subsequent dosing process.

[0088] As an alternative to using a flexible reservoir 3 pre-filled with liquid 14, the dosing device 52 can also be configured to place an empty flexible reservoir 3 with interface area 19 onto the pipe section 15 while the pressure chamber 2 is open, and then close the pressure chamber 2. In a subsequent step, the flexible reservoir 3 can be completely emptied by pressurizing the working volume 13. The pipetting tip 29 can then be immersed in a liquid to be collected in the flexible reservoir 3. To carry out this process, a vacuum is created in the working volume 13, causing liquid to be drawn into the flexible reservoir 3. With this procedure, commissioning the dosing device 1 is simpler than with P 35635 / PCT.

[0089] December 17, 2025 Use of a flexible storage container 3 already filled with liquid 14, however, it must be accepted that a certain amount of air is contained in the flexible storage container 3, which corresponds approximately to the sum of the volumes of the dosing channel 5 and the pipetting tip 29.

[0090] P 35635 / PCT

[0091] December 17, 2025

Claims

Claims 1. Metering device (1; 51) for metering a liquid, comprising a pressure chamber (2) in which a flexible reservoir (3) is received, a fluid source (4) designed to influence a working pressure in the pressure chamber (2), a metering channel (5) which is fluidically connected to the reservoir (3) and which leads out of the pressure chamber (2), a working pressure sensor (6) designed to determine the working pressure in the pressure chamber (2), and a control device (7) which is electrically connected to the working pressure sensor (6) and which is designed to evaluate sensor signals from the working pressure sensor (6).

2. Dosing device (1; 51) according to claim 1, characterized in that the flexible storage container (3) has a dimensionally stable interface area (19) which is designed for a fluid-tight plug connection with the dosing channel (5).

3. Metering device (1; 51) according to claim 1 or 2, characterized in that a flow sensor (22) is associated with the metering channel (5), which is designed to determine a quantity of liquid flowing through the metering channel (5).

4. Dosing device (1; 51) according to claim 3, characterized in that the flow sensor (22) has a first P 35635 / PCT 17 December 2025, comprising a liquid pressure sensor (23) associated with a first metering channel section (15) adjacent to the flexible reservoir (3), and a second liquid pressure sensor (24) associated with a second metering channel section (12) extending between the first metering channel section (15) and an outlet opening (18) of the metering channel (5).

5. Metering device (1; 51) according to claim 4 , characterized in that a throttle (27), in particular a static one, is arranged in the metering channel (5) between the first liquid pressure sensor (23) and the second liquid pressure sensor (24).

6. Metering device (1; 51) according to one of the preceding claims, characterized in that the fluid source (4) is designed as a fluid pump (54) for a controlled or regulated provision of an overpressure or for a controlled or regulated provision of an overpressure and for a controlled or regulated provision of a negative pressure to the pressure chamber (2) and that the fluid pump (54) is electrically connected to the control device (7).

7. Metering device (1; 51) according to claim 6 , characterized in that the fluid pump (54) has a pump chamber with an electrically volume-variable wall area made of a piezoelectric material .

8. Metering device (1; 51) according to one of claims 1 to 5, characterized in that the fluid source (4) is formed by a central compressed air network and that a pressure regulating proportional valve (16) is arranged between the fluid source (4) and the pressure chamber (2), which is electrically connected to the control device (7). P 35635 / PCT December 17, 20259. Metering device (1; 51) according to one of the preceding claims, characterized in that a metering valve (36) is associated with the metering channel (5), which is designed to block or release the metering channel (5) and which is electrically connected to the control device (7), wherein the control device (7) is designed to actuate the metering valve (36).

10. Metering device (1; 51) according to claim 6 or 7, characterized in that a supply valve (33) is associated with a supply line (32) extending between the fluid pump (54) and the pressure chamber (2), which is designed to block or release a fluidically communicating connection between the fluid pump (54) and the pressure chamber (2), wherein the supply valve (33) is electrically connected to the control device (7) and wherein the control device (7) is designed to control the supply valve (33).

11. Metering device (1; 51) according to claim 10, characterized in that a supply pressure sensor (40) is assigned to the supply line (32), which is designed to determine the supply pressure in the supply line (32) and which is connected to the control device (7), which is designed to evaluate sensor signals from the supply pressure sensor (40) and to control the fluid pump (54) in a controlled manner.

12. Metering device (1; 51) according to claim 11, characterized in that a supply valve (38) arranged between the fluid pump (54) and the supply valve (33) is associated with the supply line (32), which is connected to the control device (7) designed to control the supply valve (38). P 35635 / PCT December 17, 2025

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