LU103099B1

LU103099B1 - Pressure monitored piston pump

Info

Publication number: LU103099B1
Application number: LU103099A
Authority: LU
Inventors: Thilo Harbrich; Tibor Horvath; Martin Trump
Original assignee: Stratec Se
Priority date: 2023-04-12
Filing date: 2023-04-12
Publication date: 2024-10-14
Also published as: US20240376889A1; EP4446586A1

Abstract

The disclosure relates to a System for handling fluids comprising a manifold comprising ducts comprising fluids to be handled; a pump comprising a chamber which is filled with a medium; a bendable membrane arranged between the ducts of the manifold and the chamber of the pump for transferring pressure changes in the chamber filled with a medium to the ducts of the manifold; and a sensor which is attached to the chamber filled with a medium. A method for using the System is also disclosed.

Description

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LU103099

PRESSURE MONITORED PISTON PUMP

DESCRIPTION Field of the Disclosure

[0001] The disclosure relates to real-time process monitoring and health monitoring functionalities of a piston pump which may be used in in vitro diagnostic (IVD) analysis systems.

[0002] Devices for use in clinical diagnostics and life sciences are produced by a number of companies. For example, STRATEC® SE, Germany, manufactures numerous devices for diagnostic specimen handling and detection for use in automated analyser systems and other laboratory instrumentation.

[0003] Liquids will be used for the preparation and processing of specimen in an automated analyser. The liquids are aspirated or released by pumps. Only small volumes are to be handled in automated analyser systems so that a correct functioning of the pumps is important.

[0004] It is currently not possible to monitor the pumping process and the correct functioning of the pump itself, and in the event of a malfunction it is also not possible to distinguish whether the pump or external components (valves, hoses, etc.) cause the fault. Furthermore, neither ageing nor imminent failure of the pump can be detected.

[0005] It is therefore the objective of this disclosure to provide a device and a method for monitoring the functioning of a piston pump in [VD analysis systems.

Summary of the Invention

[0006] The present disclosure provides a system for handling fluids comprising - a manifold comprising ducts comprising fluids to be handled; 1

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LU103099 - a pump comprising a chamber which is filled with a medium; - a bendable membrane arranged between the ducts of the manifold and the chamber of the pump for transferring pressure changes in the chamber filled with a medium to the ducts of the manifold; and - à sensor which is attached to the chamber filled with a medium.

[0007] A further aspect of the disclosed system relates to the pump comprising a piston which is arranged in the chamber filled with a medium for moving the medium by increasing or minimising the volume in the chamber filled with a medium by a movement of the piston inwards or outwards of the chamber,

[0008] In a further embodiment, the piston of the pump is surrounded by bellows, wherein the bellows can be made of stainless-steel.

[0009] The system may comprise a stepper motor for moving the piston of the pump, wherein the piston of the pump may has at least partially a D-shaped circumference.

[0010] It is also intended that the system of the present disclosure comprises a valve that is arranged between a duct of the manifold which is arranged adjacent to the bendable membrane and further ducts which are connected to a supply and a disposal for the fluid to be handled.

[0011] The valve can be a 3/2-way valve.

[0012] It is intended that the sensor is fluidly connected through a hole to the chamber filled with a medium.

[0013] The system may comprise as a medium in the chamber an oil so that the chamber surrounding the bellows is filled with oil.

[0014] Another aspect of a system according to the present disclosure relates to a housing comprising the sensor which is filled with a viscose fluid in a space between the sensor and the interface to the chamber filled with a medium.

[0015] The system may further comprise a circuit board. 2

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[0016] In an embodiment of the system, the sensor is connected electrically to the circuit board.

[0017] The circuit board can comprise a data processing unit for processing data received from the sensor.

[0018] Another object of the present disclosure relates to a method for monitoring a system as described above, comprising the steps of - Measuring parameters in the chamber filled with a medium with the sensor; - Providing the measured parameter to the data processing unit on the circuit board: - Determining whether the measured data have expected values.

[0019] The method may comprise the step of preparing measurement data in analysis runs with known fluids to obtain a set of data with values to be expected.

[0020] Still other aspects, features, and advantages of the present invention are readily apparent from the following detailed description, simply by illustrating preferable embodiments and implementations. The present invention is also capable of other and different embodiments and its several details can be modified in various obvious respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention.

Summary of the Figures

[0021] The invention will be described based on figures. It will be understood that the embodiments and aspects of the invention described in the figures are only examples and do not limit the protective scope of the claims in any way. The invention is defined by the claims and their equivalents. It will be understood that features of one aspect or embodiment of the invention can be combined with a feature of a different aspect or aspects of other embodiments of the invention, in which: 3

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[0022] FIG. 1 shows a pump according to the present disclosure in a sectional view when dispensing a fluid.

[0023] FIG. 2 shows a pump according to the present disclosure in a sectional view when aspirating a fluid.

[0024] FIG. 3 shows a perspective view onto a peristaltic pump according to the disclosure.

[0025] FIG. 4 shows a sectional view through a D-shaped piston.

Detailed Description of the Invention and the Figures

[0026] The technical problem is solved by the independent claims. The dependent claims cover further specific embodiments of the invention.

[0027] A fluid within the meaning of the present disclosure relates to a liquid, a gas or a mixture thereof that is capable of flowing, wherein the fluid may comprise solids like particles. A medium in the chamber of the pump can be an oil.

[0028] A device according to the present disclosure is based on the integration of a pressure sensor directly into a pump. The sensor does not have any contact to the pumped medium in order to avoid its contamination. The sensor is connected to an existing borehole which serves for filling the pump interior with a fluid like an oil. Faults or defects in the pump can be detected by monitoring the pressure curves with the sensor during operation. In addition, with a suitable evaluation of the measured data, the cause of the fault or defect can be identified, and possible future failures can be detected in good time prior to a standstill of the pump.

[0029] The device according to the present disclosure is designed according to the principle of a piston pump. The sealing of the piston to the cylinder or chamber is often a problem in piston pumps, which is why this pump provides a hermetic separation by means of a stainless-steel bellows between the fluid or medium-filled and air-filled areas. To additionally separate the inside of the pump from the potentially critical media to be pumped, a pump according to the present disclosure provides a diaphragm or membrane which separates the fluid to be pumped 4

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LU103099 from an the medium-filled intermediate space surrounding the pump’s bellows for reliably preventing contamination of the inside of the pump by the pumped media.

[0030] The piston is surrounded by ambient air and is thus moved by a linear drive, for instance a stepper motor with spindle. Since the piston forms a unit with the bellows, this bellows is also compacted or expanded and generates an overpressure or under pressure in the medium- or oil- filled chamber. This change in pressure in the medium- or oil-filled chamber moves the diaphragm, and said movement of the diaphragm is then used to move the fluid in the manifold.

A valve in the fluid path allows the fluid to be drawn in from one direction and discharged in another.

[0031] FIG. 1 shows a pump 1 in a sectional view when dispensing a fluid and FIG. 2 shows a pump 1 when aspirating a fluid. Piston 2 is surrounded by bellows 3. An air-filled space 5 surrounds piston 2. An oil-filled piston chamber 10 surrounds the bellows.

[0032] A membrane 15 separates the oil filled piston chamber 10 from a membrane chamber 11 which is connected by a first duct 21 to valve 30. Valve 30 is connected via a second duct 22 to an inlet port 32 and via a third duct 23 to an outlet port 33. It is obvious for a skilled person that the ports may have opposite flow directions. In essence, valve 30 is a 2/3-way valve having three ports for regulating two flow directions. Ports 32, 33 and ducts 21, 22, 23 belong to manifold 20.

[0033] The movement of membrane 15 depends on the movement of piston 2. When piston 2 moves into the medium- or oil-filled piston chamber 10, the medium, like an oil causes membrane 15 to bend into membrane chamber 11 (FIG. 1). Moving piston 2 out of an oil-filled piston chamber 10, will cause membrane 15 to bend into the oil-filled piston chamber 10 through a movement of the oil (FIG. 2). Thus, a movement of piston 2 can be used to dispense or aspirate fluids through inlet port 32 and outlet port 33, respectively. To prevent under- or overpressure in the air area, the piston axis is not round but D-shaped 2d (comp. FIG. 4) in a section, wherein the D-shaped part is passing guiding 8 and there is a vent hole 6 (comp. FIG. 1 and FIG. 2) in the chamber.

[0034] FIG. 3 shows a perspective view onto a pump 1 with manifold 20 comprising inlet port 32 and outlet port 33. The sensor housing 42 which is connected to the pump’s housing 4 is also shown.

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[0035] Returning to FIG. 1, sensor 40, which can be a pressure sensor, is located in a solid housing 42 which is attached to a through hole 44 in the pump’s housing 4 which is used to fill piston chamber 10 with oil. Such an arrangement of the sensor has the advantage that an already existing interface like the through hole 44 in housing 4 can be used. The sensor will only come into contact with the oil so that there is no risk of contamination/soiling by the pumped fluid in ducts 21, 22. In addition, the inside of the sensor can be filled with a gel 45 to prevent air bubbles from remaining inside the sensor 40 after mounting and interfering with the measurement. The sensor data is processed in a processing unit (not visible) which is also located on the circuit board 50 and forwarded to a higher-level control system if required.

[0036] FIG. ! and FIG. 2 show further a circuit board 50 that also controls the movement of the motor 7. A light barrier 60 is arranged on circuit board 50, which is used to initialise the pump drive and for detecting positioning errors of the drive. The light barrier is mounted on the circuit board and configured in a manner that it is interrupted by the spindle of the motor 7. The light barrier is not interrupted in FIG. 1 and is interrupted in FIG. 2.

[0037] The sensor is primarily used for online process monitoring tasks comprising the detection of errors in the system during operation of the system, such as defects in individual components such as valves, ducts, hoses and the pump itself, During operation, pressure curves are recorded for each suction and discharge movement of the pump, ie. the course of the pressure values over time. The evaluation (and also the reaction) is usually carried out directly in the connected electronics. In the event of a defect, the process is stopped, further damage is minimised and troubleshooting/replacement of components is possible. In the event of over- pressure or under-pressure situations that exceed expected levels which may damage the pump, the process can be stopped and further damage to the pump prevented.

[0038] However, simple process monitoring of the pressure curves does not usually allow the cause of the fault to be identified; a service technician will usually be required for troubleshooting.

[0039] To also enable an automatic recognition of the cause of the fault and to detect imminent failures or ageing effects in advance, the measurement data of the pressure sensor is also evaluated by a higher-level control system. The software of this control system also considers the history of the pressure curves and evaluates the complete curve progressions. Statically 6

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LU103099 programmed algorithms for the evaluation of individual curve parameters (e.g. peak value, slope, times...) as well as intelligent machine learning approaches and self-learning neuronal networks are conceivable.

[0040] The generation of the measurement data can take place either during operation or in one or more analysis runs. In these analysis runs, the pump can then be operated with parameters that would not be possible or harmful in normal operation like pumping slowly/cautiously against a closed valve for determining the elasticity of the system. Since in this case all other parts of the system are disconnected after the valve, it is very easy to identify faults in the pump itself.

[0041] Ideally, the system behaves very directly/stiffly due to the oil coupling. However, if there are air bubbles in the oil, e.g. caused by excessive under pressure due to outgassing, these air bubbles act like a spring in the system, thus changing the pump's response behaviour and thus the precision, Excessive negative pressure is therefore particularly critical for this pump technology and must be prevented or at least detected in time.

[0042] Observing the pressure curve over a longer period of time enables to detect a trend caused by the ageing of the components. In this way, it is also possible to plan a service visit before components fail.

[0043] In principle, the analyses can be carried out with the help of data obtained in the process, from data from special analysis runs and measurement data which have the hydrostatic pressure as their cause. Optionally also a combination of all.

[0044] Hydrostatic pressure refers to the static pressure that arises depending on the position of the reservoir in relation to the pump and can generate pressure peaks in the switching moments of the valve.

[0045] To monitor the positioning of the pump drive, the light barrier position is approached cyclically, and the expected position is compared with the actual position. Since the motor is a step motor, the steps serve as information on the expected distance travelled. If there is a deviation between the actual position and the target position, there is an error. 7

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[0046] In summary, the present disclosure provides a sensor for detecting the following faults: - Leakage - Sudden drop in pressure or generally lower pressure level - Clogging - Sudden pressure increase or generally higher pressure level - Defects of the spindle nut/spindle of the motor - Position error of the drive and/or unexpected jumps in the pressure curve. - Pressure change later than expected will generate a time offset - Defects in the diaphragm or bellows (crack/break) - Change in the pressure curve - Temperature effects ~ Change in the pressure curve - Air bubbles in the oil - Additional elasticity in the system/change in the pressure curve

[0047] The advantages of the device and system according to the disclosure can be summarised as: - Detection and prevention of defects in the system - No contamination of the sensor due to coupling with the oil chamber - No risk of corrosion of the pressure sensor due to contact with critical media

[0048] The foregoing description of the preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiment was chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents. The entirety of each of the aforementioned documents is incorporated by reference herein. 8

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LU103099

Reference Numerals

I pump 2 piston 2d D-shaped piston 3 bellows 4 pump housing air-filled space 6 vent hole 7 motor 8 guiding piston chamber 11 membrane chamber membrane manifold 21 first duct 22 second duct 23 third duct valve 32 inlet port 33 outlet port

Sensor 42 sensor housing 44 through hole gel circuit board 60 light barrier 9

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1. A system for handling fluids comprising - a manifold comprising ducts comprising fluids to be handled; - a pump comprising a chamber which is filled with a medium; - a bendable membrane arranged between the ducts of the manifold and the chamber of the pump for transferring pressure changes in the chamber filled with a medium to the ducts of the manifold; and - a sensor which is attached to the chamber filled with a medium. 2. The system of claim 1, wherein the pump comprises a piston which is arranged in the chamber filled with a medium for moving the medium by increasing or minimising the volume in the chamber filled with a medium by a movement of the piston inwards or outwards of the chamber. 3, The system of claim 2, wherein the piston of the pump is surrounded by bellows. 4. The system of claim 3, wherein the bellows are made of stainless-steel.

S. The system of any one of claims 1 to 4, comprising a stepper motor for moving the piston of the pump. 6. The system of any one of claims 2 to 5, wherein the piston of the pump has at least partially a D-shaped circumference. 7. The system of any one of claims 1 to 6, wherein a valve is arranged between a duct of the manifold which is arranged adjacent to the bendable membrane and further ducts which are connected to a supply and a disposal for the fluid to be handled. 8. The system of claim 7, wherein the valve is a 3/2-way valve. 9. The system of any one of claims 1 to 8, wherein the sensor is fluidly connected through a hole to the chamber filled with a medium.

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LU103099 10. The system of any one of claims 1 to 9, wherein the medium in the chamber is an oil. 11. The system of any one of claims 1 to 10, wherein a housing comprising the sensor is filled with a viscose fluid in a space between the sensor and the interface to the chamber filled with a medium. 12. The system of any one of claims 1 to 11, comprising a circuit board. 13. The system of claim 12, wherein the sensor is connected electrically to the circuit board. 14. The system of claims 12 or 13, wherein the circuit board comprises a data processing unit for processing data recetved from the sensor. 15. A method for monitoring a system according to any one of claims 1 to 14, comprising the steps of - Measuring parameters in the chamber filled with a medium with the sensor; - Providing the measured parameter to the data processing unit on the circuit board: - Determining whether the measured data have expected values. 16. The method of claim 15, comprising the step of preparing measurement data in analysis runs with known fluids to obtain a set of data with values to be expected. 11

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ABSTRACT

The disclosure relates to a system for handling fluids comprising a manifold comprising ducts comprising fluids to be handled; a pump comprising a chamber which is filled with a medium; a bendable membrane arranged between the ducts of the manifold and the chamber of the pump for transferring pressure changes in the chamber filled with a medium to the ducts of the manifold; and a sensor which is attached to the chamber filled with a medium. A method for using the system is also disclosed. 12

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Claims

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1. A system for handling liquids, comprising: - a distributor with lines for the liquids to be pumped; - a pump with a chamber filled with a medium; - a flexible membrane arranged between the channels of the distributor and the chamber of the pump to transmit pressure changes in the chamber filled with a medium to the channels of the distributor; and - a sensor attached to the chamber filled with a medium.

2, The system of claim 1, wherein the pump comprises a piston disposed in the medium-filled chamber for moving the medium by increasing or decreasing the volume in the medium-filled chamber by movement of the piston into or out of the chamber.

3. The system of claim 2, wherein the piston of the pump is surrounded by a bellows.

4. The system of claim 3, wherein the bellows are made of stainless steel.

3. The system of any one of claims 1 to 4, including a stepper motor for moving the piston of the pump.

6. The system according to any one of claims 2 to 5, wherein the piston of the pump has at least partially a D-shaped circumference,

7. System according to one of claims 1 to 6, characterized in that a valve is arranged between a channel of the distributor, which is arranged next to the flexible membrane, and further channels which are connected to a supply and disposal for the fluid to be conveyed.

8. The system of claim 7, wherein the valve is a 3/2-way valve.

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9. The system according to any one of claims 1 to 8, wherein the sensor is in fluid communication with the chamber filled with a medium through a hole,

10. The system of any one of claims 1 to 9, wherein the medium in the chamber is an oil.

11. The system according to any one of claims 1 to 10, wherein a housing with the sensor is filled with a viscous liquid in a space between the sensor and the interface to the medium-filled chamber.

12. The system of any of claims 1 to 11, comprising a circuit board.

13. The system of claim 12, wherein the sensor is electrically connected to the circuit board.

14 The system of claim 12 or 13, wherein the circuit board comprises a data processing unit for processing the data received from the sensor.

15. A method for monitoring a system according to one of claims 1 to 14, comprising the following steps - measuring parameters in the chamber filled with a medium with the sensor; - transferring the measured value to the data processing unit on the circuit board; - determining whether the measured data have expected values.

16. The method of claim 15, comprising the step of processing measurement data in analysis runs with known fluids to obtain a data set with expected values.