LU501940B1 - Method for determining a leak in a dispensing device for dispensing liquid - Google Patents
Method for determining a leak in a dispensing device for dispensing liquid Download PDFInfo
- Publication number
- LU501940B1 LU501940B1 LU501940A LU501940A LU501940B1 LU 501940 B1 LU501940 B1 LU 501940B1 LU 501940 A LU501940 A LU 501940A LU 501940 A LU501940 A LU 501940A LU 501940 B1 LU501940 B1 LU 501940B1
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- LU
- Luxembourg
- Prior art keywords
- liquid
- receptacle
- dispensing
- pressure
- dispensing device
- Prior art date
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- 239000007788 liquid Substances 0.000 title claims abstract description 178
- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000003825 pressing Methods 0.000 claims abstract description 4
- 238000012545 processing Methods 0.000 claims description 48
- 238000012360 testing method Methods 0.000 claims description 38
- 238000004590 computer program Methods 0.000 claims description 8
- 239000012530 fluid Substances 0.000 description 11
- 230000006870 function Effects 0.000 description 7
- 239000002245 particle Substances 0.000 description 4
- 238000012546 transfer Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 239000000969 carrier Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000036962 time dependent Effects 0.000 description 2
- 238000012549 training Methods 0.000 description 2
- 241000894006 Bacteria Species 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 241000233866 Fungi Species 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 240000004808 Saccharomyces cerevisiae Species 0.000 description 1
- 241000700605 Viruses Species 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000012864 cross contamination Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000007641 inkjet printing Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- -1 polypropylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 208000024891 symptom Diseases 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
- G01M3/28—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for pipes, cables or tubes; for pipe joints or seals; for valves ; for welds
- G01M3/2853—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for pipes, cables or tubes; for pipe joints or seals; for valves ; for welds for pipe joints or seals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
- B01L3/02—Burettes; Pipettes
- B01L3/0241—Drop counters; Drop formers
- B01L3/0268—Drop counters; Drop formers using pulse dispensing or spraying, eg. inkjet type, piezo actuated ejection of droplets from capillaries
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L2200/00—Solutions for specific problems relating to chemical or physical laboratory apparatus
- B01L2200/06—Fluid handling related problems
- B01L2200/0689—Sealing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L2200/00—Solutions for specific problems relating to chemical or physical laboratory apparatus
- B01L2200/14—Process control and prevention of errors
- B01L2200/143—Quality control, feedback systems
- B01L2200/146—Employing pressure sensors
Abstract
The invention relates to a method for determining a leak in a dispensing device for dispensing liquid, wherein the dispensing device comprises a dispensing head for applying pressure on a receptacle comprising an inlet opening for inletting liquid into the receptacle and an outlet opening for dispensing liquid from the receptacle when a pressure is applied on the liquid, wherein the method comprises the following steps preventing that liquid is dispensed by the dispensing device when a pressure is applied on the liquid, applying a pressure on the liquid, measuring a pressure applied on the liquid and determining on the basis of the measured pressure whether the dispensing device (5)
Description
26.04.2022 005A0018LU 1
LU501940
Method for determining a leak in a dispensing device for dispensing liquid
The invention relates to a method for determining a leak in a dispensing device for dispensing liquid.
Additionally, the invention relates to a dispensing device for dispensing liquid, a computer program product, a computer readable data carrier and a data carrier signal.
Liquid handling is a fundamental process in many laboratories. In modern life science laboratories, high-throughput liquid handling is frequently needed for the purpose of efficiency. For liquid dispensing at the micro-, nano- or even picolitre level, the surface adhesion is a fundamental factor that affects the performance. Basically, liquid-dispensing technologies have to overcome surface adhesion and dispense the droplet from the dispensing tool. When the volume is very small, gravity is not sufficient for dropping viscous samples. A variety of methods have been developed to overcome the problem by generating additional driving forces to dispense the droplet. In general, those methods can be classified into two categories: contact and noncontact dispensing, respectively.
In contact dispensing techniques, such as pipetting, a touch-off is necessary to complete the liquid dispensing. When the liquid attaches to a substrate, a drag-back action is done to overcome the surface tension between liquid and the dispensing tip, without which the liquid will not drop.
Contact dispensing is most popular for dispensing samples of small volume from nano- to microliter because of its simplicity, reliability, and low cost. However, reliable dispensing requires an accurate positioning system. Furthermore, special attention must be paid to hard contact, which may damage the dispenser tip by colliding with the container.
In noncontact dispensing techniques, the liquid is ejected from an orifice instead of using a contact between the liquid and the surface container. It reduces or eliminates some disadvantages of contact dispensing mentioned above. In particular, cross-contamination can be avoided. The most common approaches are based on the inkjet printing technology, thereby using different dispensing means, such as solenoid valves, piezoelectric dispensers, acoustic dispensers, electrostatic devices, etc..
Typically, liquid handling refers to small volume dispensing operations, however, at the micro-, nano- or picolitre level, the number of transferred samples can be huge. Under these conditions, liquid handling by hand can be very time-consuming and, in some cases, impractical.
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Consequently, there is a strong demand for automated liquid handling systems. From the prior art, dispensing devices are known that comprise a dispensing head by means of which a pressure is applied on a liquid in a receptacle having an outlet opening. Due to the pressure a liquid is dispensed from the receptacle. There exists the need to secure that the dispensed liquid volume corresponds with a predetermined liquid volume independent of several parameters like the receptacle volume and/or the used liquid type. This is in particular important for liquids that are expensive and/or where the available liquid volume is small.
In an operation mode of the dispensing device it is not always possible to ensure that the dispensed liquid volume corresponds with the predetermined liquid volume. The incorrect dispensing can have several reasons. One of the reasons is that the dispensing device has one or more leaks so that the applied pressure does not corresponds with a target pressure that is set by a data processing unit of the dispensing device for controlling the dispensing device. As the dispensed liquid volume depends on the applied pressure, a difference between the applied pressure and the target pressure leads to an inaccurate dispensing step. The leak can result from material wear and/or an incorrect assembly of the device.
It is known to inspect the dispensing device manually when the dispensed liquid volume does not correspond with the predetermined liquid volume or regardless of the dispensing performance within the scope of maintenance or service. As the reason for the incorrect dispensing often cannot be identified, if this is even the case, all components can be exchanged that could lead to the incorrect dispensing or the other encountered symptom entirely or sequentially. However, this process is time consuming and often components are exchanged which are not the reason for the incorrect dispensing step resulting in unnecessary costs.
The object of the invention is to provide a method by means of which a reason for an inaccurate dispensing can be identified in a simple and cost-effective manner.
The object is solved by a method for determining a leak in a dispensing device for dispensing liquid, wherein the dispensing device comprises a dispensing head for applying pressure on a receptacle comprising an inlet opening for inletting liquid into the receptacle and an outlet opening for dispensing liquid from the receptacle when a pressure is applied on the liquid, wherein the method comprises the following steps
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LU501940 preventing that liquid is dispensed by the dispensing device when a pressure is applied on the liquid, applying a pressure on the liquid, measuring a pressure applied on the liquid and determining on the basis of the measured pressure whether the dispensing device has a leak.
Another object of the invention is to provide a dispensing device in which a reason for an inaccurate dispensing can be identified in a simple and cost-effective manner.
The object is solved by a dispensing device for dispensing liquid, in particular for executing an inventive method, wherein the dispensing device comprises a holder for holding a carrier comprising at least one receptacle comprising an inlet opening for inletting liquid into the receptacle and an outlet opening for dispensing liquid from the receptacle when a pressure is applied on the liquid, a dispensing head for providing a pressure on the receptacle, a pressure sensor for measuring pressure applied on the liquid and a data processing unit that is configured to determine on the basis of the measured pressure whether the dispensing device has a leak.
The invention has the advantage that it is possible to easily check whether the dispensing device has a leak. If it is determined that the dispensing device has a leak the corresponding components that are responsible for the leak can be exchanged. Thus, for the leakage test it is not necessary to remove all components that might be the reasons for an inaccurate dispensing step. Therefore, the user can maintain the dispensing device in a fast and cost-effective manner. In particular, it is possible to determine whether the dispensing device has a leak without disassembling the dispensing device. The determination can be performed without the need to reassemble the dispensing device resulting in an easy way to perform the leakage test.
In a proper working dispensing device, the applied pressure is released through the outlet opening through which the liquid is dispensed. “Leak” means that the pressure can be released at another place in the fluid path between a pressure source and the outlet opening of the receptacle, in particular between a valve of the dispensing device and the outlet opening of the receptacle.
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The receptacle is capable of holding and releasing a liquid, in particular onto a target plate or into a target receptacle of a target carrier, only when a defined pressure, in particular pressure pulse, is applied on top of the receptacle. In particular, the pressure is applied on the liquid arranged in the receptacle. When there is no pressure pulse applied on the receptacle, no liquid is released since capillary forces keep the liquid in the cavity. That means, no liquid is released due to the atmosphere pressure acting on the liquid.
A receptacle can be made out of polymers (e.g., polypropylene), metals (e.g., aluminum, copper) and/or glass. When a pressure, in particular pressure pulse is applied, on top of the receptacle a liquid droplet or liquid jet is released on a target carrier arranged below the receptacle. With “applying pressure on the liquid” it is meant that a pressure being different, in particular higher, than the atmospheric pressure is applied on the liquid.
The receptacle can be arranged in a through hole of a carrier, in particular of a carrier element, in a releasable manner. That means, the connection between the receptacle and the carrier element can be disconnected without destroying the receptacle and/or the carrier element. Additionally, the receptacle can be inserted into the through hole or removed from the through hole without the use of any tools. Alternatively, the receptacle and the carrier element can be made in one form. In said embodiment each receptacle bottom has at least one outlet opening. Said embodiment can be used if the carrier has 384 or more receptacles.
The carrier can have one or more receptacles. Carriers that have more than one receptacle are also indicated as multiwell plate. In particular, carriers are known that have 6, 12, 24, 48, 96, 384, 1536 and 3456 receptacles. The receptacles are arranged in a matrix structure on the carrier element, in particular in the through holes of the carrier element.
The outlet opening of the receptacle, in particular of the first receptacle and/or the second receptacle, can have a diameter between 60pm (micrometer) and 200um, in particular 100pm. The dispensed liquid can be a liquid droplet or a liquid jet and/or have a volume of at least 10 nanoliters.
In particular, the dispensed liquid can have a volume in the range between 10 nanoliters to 100 nanoliters. Larger volumes are achieved by applying up to 100 pulses per second on the receptacle.
The maximum volume of the dispensed liquid per receptacle is the receptacle volume. The receptacle can have a volume between 80 microliters to 800 microliters. The initial volume of liquid arranged in the receptacle can be between 10 microliters to 500 microliters.
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The liquid depends on the usage field of the dispensing device. The liquid can contain at least one biological particle. The biological particles may be microorganisms such as bacteria, archaean, yeast, fungi, and viruses or cells, DNA, RNA, or proteins. The liquid may have a single or multiple of the 5 aforementioned biological particles. The liquid can promote the growth of the biological particles, in particular cells, arranged in the liquid. Alternatively, the liquid can comprise merely liquids, e.g. one or more chemical reagents.
The data processing unit is an electric or electronic unit. The data processing unit can comprise one or more processors for processing data. Alternatively, the data processing unit can be a processor for processing data. In particular, the data processing unit can comprise a printed circuit board. The data processing unit can be used for controlling the dispensing device, in particular the dispensing head. In particular, the data processing unit can set the volume of liquid to be dispensed from a receptacle as is explained below.
According to an embodiment the outlet opening of the receptacle of the carrier can be closed by a closing element. The closing element can be attached to the receptacle, in particular a bottom of the receptacle comprising the outlet opening. The attachment can be in releasable manner so that the same receptacle can be reused in the operation mode of the dispensing device in which liquid is dispensed.
Alternatively, the receptacle can be exchanged by a test receptacle that comprises an inlet opening for inletting liquid into the test receptacle and a closed bottom. The test receptacle can be part of a test carrier that can comprise one or more test receptacles. “Closed bottom” means that the receptacle does not have an outlet opening through which the liquid can be dispensed. The test receptacle can be inserted into the holder of the dispensing device. After performing the leakage test the test receptacle is exchanged with a receptacle having a outlet opening for dispensing liquid so that the dispensing device can be operated in the operation mode.
Both aforementioned receptacle types are used during the determination whether the dispensing device has a leak. According to both options it is easy to prevent that liquid is dispensed from the receptacle. That means, the applied pressure in the dispensing device is not released or is not released as fast as in a dispensing step. In other words, as no liquid can be dispensed the applied pressure cannot be released so that the pressure is applied within the fluid path between the
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LU501940 pressure source and the receptacle. By considering the pressure it is possible to determine whether the dispensing device has a leak. In a dispensing device that does not have a leak, the measured pressure is constant or decreases slow whereas in dispensing device having a leak the measured pressure decreases fast.
The pressure sensor is configured to measure the pressure applied on the liquid. The data processing unit and/or the pressure sensor can determine a pressure course on the basis of the measured pressure. In particular, a pressure course can be determined during a predetermined time period. The data processing unit can determine on the basis of the pressure course whether the dispensing device has a leak. The pressure course can be stored in an electric or electronical memory. Using the pressure course instead of single measured pressure values has the advantage that a time period is considered for the decision whether the dispensing device has a leak. This prevents for example that a wrong decision is made dependent on a wrongly measured pressure value.
According to an embodiment the dispensing device can comprise a valve. The valve can be opened in order to apply a pressure on the liquid and/or can be arranged in the dispensing head or outside the dispensing head. In addition, the valve can be used to fluidically connect a pressure source and the receptacle or to fluidically disconnect the pressure source and the receptacle. In an open position the valve fluidically connects the pressure source and the receptacle. In a closed position the valve fluidically disconnects the pressure source and the receptacle. The position of the valve can be controlled by the data processing unit. The pressure source can be a pressure tank providing positive pressure, i.e. pressure that is higher than atmospheric pressure.
The data processing unit can act on the valve so that the valve is arranged in the closed position after the pressure is applied on the liquid. The valve can remain closed, i.e. is in the closed position, during the determination whether the dispensing device has a leak. Thus, it is ensured that the pressure can decrease within the fluid path between the closed valve and the receptacle. Said pressure can be determined by considering the measured pressure.
The data processing unit can determine that the dispensing device has a leak when the measured pressure fulfills a predetermined condition with respect to a predetermined threshold. In particular, the data processing unit can determine that the dispensing device has a leak when the measured pressure is below the predetermined threshold within a predetermine time period and/or when the
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LU501940 pressure course is below the predetermined threshold for a predetermined time within a predetermined time period. The data processing unit can determine that the dispensing device does not have a leak, when the measured pressure fulfills another predetermined condition with respect to a predetermined threshold within a predetermined time period. The another predetermined condition can be whether the measured pressure is above the predetermined threshold and/or whether the pressure course is above the predetermined threshold within the predetermined time period. Thus, it is possible to determine whether the dispensing device has a leak in an easy and fast manner by considering whether the measured pressure and/or determined pressure course fulfil a condition or a predetermined condition. The starting point of the time period can be the time when the valve is closed.
The dispensing device can be enabled to dispense liquid, when it is determined that the dispensing device does not have a leak in the leakage test. Thereto, the closing element is removed from the receptacle or a receptacle comprising an outlet opening is inserted into the holder of the dispensing device. Thus, it is not time consuming to prepare the dispensing device so that it can be operated in the operation mode after the leakage test is finished. For performing the operation mode, the receptacle, which has an inlet opening for inletting a liquid into the receptacle and an outlet opening for dispensing liquid from the receptacle when a pressure is applied on the liquid, or the carrier having said receptacle is arranged in the holder of the dispensing device. In the operation mode a dispensing step is performed, in which liquid is dispensed from the receptacle.
According to an embodiment the dispensing head can have at least one dispensing line, wherein the dispensing line has a seal. The dispensing line is used for transferring the pressure provided by the pressure source to the receptacle. The dispensing head can have several dispensing lines, in particular eight dispensing lines. Each of said dispensing lines can be assigned to a receptacle. The dispensing head can be configured such that the dispensing lines can transfer pressure to the respective receptacle at the same time. Alternatively, it is possible that only a part of the dispensing lines transfer pressure to receptacles. The dispensing device can comprise several valves, wherein the valves are assigned to at least one dispensing line. That means, the valve position determines whether a dispensing line transfers pressure to the receptacle and/or which dispensing line transfer pressure to the receptacle.
The seal can be arranged at one end of the dispensing line. In particular, the seal can be arranged at the end of the dispensing line that is distant to the pressure source. The seal can be in contact with
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LU501940 the receptacle when it is determined whether the dispensing device has a leak. That means, the seal can be in contact with the receptacle during the leakage test. This is useful as the seal is also in contact with the receptacle during a dispensing step in which pressure is applied on the liquid located in the receptacle in order to dispense liquid from the receptacle. The seal can have a circular cross section and/or can be shaped such that it surrounds a fluid channel of the dispensing line, wherein the fluid channel is used for transferring pressure to the receptacle. Thus, the seal shall ensure that the pressure transferred by the dispensing line is released by dispensing liquid and not via a leak between the dispensing line and the receptacle.
The pressure sensor can be arranged in or on the dispensing line. Thus, the pressure sensor measures the pressure being in a fluid channel of the dispensing line.
The dispensing head and the holder are moveable relative to each other. Thus, it is possible to dispense liquids from the carrier having a plurality of receptacles and being arranged in the holder.
The dispensing head and/or the holder can move in a linear direction. The dispensing line and the receptacle or test receptacle can be arranged coaxial to each other during the leakage test.
Additionally, the dispensing line and the receptacle can be arranged coaxial to each other during a dispensing step in an operation mode of the dispensing device.
The dispensing head, in particular the dispensing line, can be moved along a direction that is coaxial or parallel to a length axis of the receptacle. The movement occurs so that the seal comes into contact with the receptacle for performing the leakage test or dispensing step or to release the contact of the seal with the receptacle. The dispensing head is moved in a direction so that the seal comes into contact with the receptacle wherein said direction is opposite to a direction when the dispensing head is moved in order to release the contact of the seal with the receptacle.
The dispensing device can comprise a target carrier holder for a target carrier. The target carrier holder can comprise at least one target receptacle for receiving the dispensed liquid. The target carrier holder can be arranged below the receptacle or the carrier comprising the at least one receptacle. The target carrier can be a multiwell plate.
According to a further aspect of the invention a computer program product is provided wherein the computer program product comprises instructions which, when the program is executed by the data processing unit cause the dispensing device to carry out the steps of the inventive method.
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Additionally, a computer-readable data carrier is provided wherein the computer-readable data carrier has stored thereon the computer program product. Also a data carrier signal is provided wherein the data carrier signal carries the computer program product.
In the figures, the subject matter of the invention is shown schematically, with identical or similarly acting elements being mostly provided with the same reference signs. Therein shows:
Fig. 1 a cross section view of a part of a dispensing device according to a first embodiment wherein the dispensing device is operated in an operation mode,
Fig.2 across section view of a part of a dispensing device according to a second embodiment,
Fig. 3 a cross section of the part of the dispensing device according to the first embodiment, which performs a leakage test,
Fig. 4 a flow chart of the method for determining a leak in a dispensing device,
Fig. 5 a diagram showing pressure courses in a leakage test process,
Fig. 6 a flow chart of the method for setting the volume of liquid to be dispensed and
Fig. 7 a perspective view of a part of a dispensing device.
Fig. 1 shows a cross section of a part of a dispensing device 5 according to a first embodiment. In particular, fig. 1 shows a hollow dispensing line 15 of a dispensing head 8. The dispensing head 8 is arranged in its dispensing position in which a dispensing line 15 is arranged on a receptacle 2 comprising liquid 1. Thus, the dispensing head 8 is not in direct contact with the liquid 1. The dispensing head 8 comprises a seal 16 that is arranged between the dispensing line 15 and the receptacle. The seal 16 is in contact with the receptacle and prevents that fluid, in particular gas flowing in the dispensing line, leaks between the receptacle 2 and the dispensing line 15.
Additionally, the dispensing is electrically connected with a non-shown data processing unit. The data processing unit can control at least one valve arranged in the dispensing head 8 for applying the pressure to the liquid arranged in the receptacle 2.
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The receptacle 2 is arranged on a carrier 7 and comprises an outlet opening 4 at its bottom.
Additionally, the receptacle 2 comprises an inlet opening 3 through which liquid 1 can be inserted into the receptacle 2. The inlet opening 3 and the outlet opening 4 are arranged at ends of the receptacle 2 that are opposite to each other.
By applying a pressure on the liquid 1 by means of the dispensing line 15 a droplet is dispensed from the receptacle 2. The pressure apply is indicated by the arrow in figure 1. The pressure enters the receptacle via the inlet opening 3. A pressure sensor 10 is attached on the dispensing line 15.
The pressure sensor 10 is configured to measure the pressure arranged in the area of the receptacle 2 that is arranged above the liquid 1. Additionally, it is possible to measure a time duration in which the pressure is applied to the liquid 1. In order to apply a pressure on the liquid 1 a valve 16 shown in fig. 3 is opened.
Fig. 2 shows a cross section of a part of a dispensing device 5 according to a second embodiment.
The second embodiment differs from the first embodiment in the structure of the carrier 7. The carrier 7 does not have a receptacle 2 that can be released from the carrier 7. The receptacle 2 and the carrier 7 are formed as one part. Each of the receptacles 2 has the outlet opening 4 at its bottom. Likewise, to the embodiment shown in fig. 1, the outlet opening 4 has such a size that capillary forces are so high that liquid 1 cannot flow out of the receptacle 2 if no pressure is applied on the liquid by means of the dispensing head 8. As is evident from fig. 2, the data processing unit 9 is connected to the dispensing head 8.
The dispensing device 5 comprises several liquid acquisition devices 17. Each of the liquid acquisition devices 17 comprises a source 18 for emitting a light beam and receiver 19 for receiving the emitted light beam. The liquid acquisition device 17 is arranged below the carrier 7 and a holder 6 for holding the carrier 7. In particular, the liquid acquisition device 17 is attached to the lower surface of the holder 6 that faces a target carrier 12 discussed below.
The liquid acquisition device 17 is arranged such that a dispensed liquid passes between the source 18 and the receiver 19 and, thus, interrupts the non-shown light beam. Thus, the liquid acquisition device 17 acquires that a liquid is dispensed from the first receptacle 2. Each of the first receptacles 2 of the carrier 7 is assigned to a liquid acquisition device 17. Thus, the number of liquid acquisition devices 17 corresponds with the number of first receptacles 2 from which liquid is dispensed. The liquid acquisition devices 17 are electrically connected to the data processing unit 9.
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A target carrier 12 is arranged below the carrier 7. The target carrier 12 comprises a plurality of target receptacles 13 for receiving the liquid dispensed from first receptacles 2 of the carrier 7. A target carrier holder 11 is provided that holds the target carrier 12. The target carrier holder 11 moves the target carrier 12 relative to the carrier 7. The data processing unit 9 is electrically connected with the target carrier holder 11.
The dispensing head 8, the carrier 7 and the target carrier 12 can move relative to each other. The data processing unit 9 controls the movement of at least one of said components with respect to the remaining components.
As is described below more in detail, in a leakage test of the dispensing device 5, the data processing unit 9 is configured to determine whether the dispensing device 5 has a leak on the basis of the measured pressure.
Fig. 3 shows a cross section of the part of the dispensing device 5 according to the first embodiment, wherein a leakage test is performed for the dispensing device 5. The leakage test can be performed in the same manner for the dispensing device 5 shown in fig. 2.
In addition to the components described in figures 1 and 2, the dispensing device comprises a valve 24. The valve 24 can be attached to the dispensing head or arranged inside the dispensing head. The data processing unit 9 is electrically connected to the valve 24 and the pressure sensor 10. In particular the data processing unit 9 can control the position of the valve 24. In an open position of the valve 24 a pressure source 25 like a pressure tank is fluidically connected with the receptacle 2.
In particular, the pressure provided by the pressure source 25 is applied on the liquid 1 when the valve 24 is in the opened position. The pressure source 25 provides a positive pressure.
In an open position of the valve 24 a fluid path exists between the pressure source 25 via the dispensing head 8 to the receptacle 2. Thus, in the open position of the valve 24 the pressure provided by the pressure source 25 is applied on the liquid 1 arranged in the receptacle 2. A closing element 14 is attached to the end of the receptacle 2. Said closing element 14 covers the outlet opening 4 and prevents that liquid 1 is dispensed from the receptacle due to the pressure apply on the liquid 1 in the leakage test. In a closed position of the valve 24, the valve disconnects a fluid connection between the pressure source 25 and the dispensing head 8 and thus the receptacle 2.
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The leakage test can also be performed by using a non-shown test receptacle. Said test receptacle does not have an outlet opening 4 but a closed bottom so that no liquid 1 can be dispensed from the test receptacle when a pressure is applied on the liquid 1. If the test receptacle is used, the closing element 14 is not needed.
Fig. 4 shows a flow chart of the method for determining a leak in a dispensing device 5 in a leakage test. In a first step S1 a closing element 14 is attached to the receptacle 2. If the dispensing head 8 has several dispensing lines 15, a closing element 14 is attached to each of the receptacles 2 which are assigned to a dispensing line 15, in particular which are in contact with the seal 16 of the dispensing head 8. Alternatively it is possible to exchange the receptacle 2 by a test receptacle, which does not have an outlet opening 4. Independent which possibility is chosen, at the end of the first step S1 no liquid is dispensed by the dispensing device 5 when a pressure is applied on the liquid arranged in the receptacle 2 or a non-shown test receptacle.
In a second step S2, the data processing unit 9 acts on the valve 24 so that it moves into the open position. In said position the pressure provided by the pressure source 25 is transferred via the dispensing head 8, in particular the dispensing line 15, to the receptacle 2. At the end of the second step S2 a pressure is applied on the liquid 1 located in the receptacle 2.
At a third step S3 the data processing unit 9 acts on the valve 24 so that it moves into the closed position. In the closed position the valve 24 disconnects the fluid connection between the pressure source 25 and the receptacle 2. Thus, the pressure sensor 10 measures the pressure that is applied in the fluid path between the closed valve and the receptacle.
In a fourth step S4 the data processing unit 9 determines on the basis of the measured pressure whether the dispensing device 5 has a leak. This is explained more in detail by referring to figure 5.
Figure 5 shows a diagram showing pressure courses in the leakage test process over the time. The pressure course consists of the pressure values measured by the pressure sensor 10. In particular, figure 5 shows two pressure courses, namely a first pressure course p1 corresponding to a pressure course when the dispensing device 5 has no leak and a second pressure course p2 corresponding to a pressure course when the dispensing device 5 has a leak. The first pressure course p1 is shown in solid line and the second pressure course p2 is shown in dotted lines.
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As is evident from figure 5 the pressure of both pressure courses p1, p2 starts to increase from a first time t1 until a second time t2. The first time t1 corresponds with the time when the data processing unit 9 acts on the valve 24 to move in the open position as discussed above. At the second time t2 the data processing unit 8 acts on the valve 24 to move in the closed position.
The data processing device 8 considers the pressure course to determine whether the dispensing device has a leak. In particular, the data processing unit 8 considers a predetermined time period that corresponds to the time period between the second time t2 and a third time t3. Thus, the predetermined time period starts from the second time t2, when the valve 16 is closed. The data processing unit 8 considers the pressure drop within said predetermined time period. If the pressure drops below a predetermined threshold T within the predetermined time period, the data processing unit 8 determines that the dispensing device 5 has a leak. If the pressure drop is small and does not fall below the threshold T within the predetermined time period, the data processing unit 8 determines that the dispensing device 5 does not have a leak.
The first pressure course p1 has pressure value that is above the threshold T during the predetermined time period. Thus, the data processing unit 8 determines on the basis of the measured pressures that the dispensing device 5 does not have a leak. The second pressure course p2 falls below the threshold at the time t4. As the time t4 is within the considered predetermined time period, the data processing unit 8 determines due to the fast pressure drop that the dispensing device 5 has a leak.
Fig. 6 shows a flow chart of the method for setting the volume of liquid to be dispensed, wherein the method is performed in the dispensing device 5 according to the first or second embodiment. In particular, an operation mode of the dispensing device 5 is explained below. The operation mode can be performed before or after the leakage test explained above with respect to figures 4 and 5.
In a first step T1 the user enters the predetermined volume of liquid 1 to be dispensed into the dispensing device 5 and the volume of liquid that is arranged in at least one first receptacle 2.
Thereto, the dispensing device 5 can have an input means like a keyboard and/or touch display. The user can enter one volume of liquid to be dispensed by each receptacle. Alternatively, it is possible to enter a volume of liquid to be dispensed separate for each receptacle 2.
In a second step T2, a data processing unit 9 sets a volume of liquid 1 to be dispensed by
26.04.2022 005A0018LU 14
LU501940 considering the entered, predetermined volume of liquid to be dispensed. In particular, the data processing unit 9 sets the volume of liquid 1 to be dispensed such that it corresponds or basically corresponds with the predetermined volume of liquid 1 that was entered in the first step S1.
Thereto, the data processing unit 9 controls the dispensing head 8 such that a control variable, in particular the applied pressure or the time duration over which the valve is kept open, is set such so that the determined volume of liquid that is dispensed corresponds or basically corresponds with the predetermined volume of liquid. The pressure can be time dependent. In particular, the pressure applied on the liquid can be a time dependent function. Thus, the control variable can be a pressure integral.
In the following, it is explained more in detail how the volume of liquid to be dispensed is set by the data processing unit 9. À possibility is to use a function, in particular a polynomial, to calculate the volume of liquid to be dispensed. In particular, the following equation is used to calculate the volume of liquid to be dispensed:
F1 = (ao + ar*u + a2*uU* + as*u’) wherein "F1" is the function result and corresponds with the volume of liquid to be dispensed, “u” is the control variable, “ao … az” are the constants of the polynomial.
The coefficients of the function are determined in a training mode. The training mode is made in a step that is previous to the first step T1 and is not explained more in detail. The function result F1 is calculated by using a polynomial of 3™ degree wherein the pressure u applied on the liquid 1 is the variable of the polynom. Alternatively, polynoms with other degree may be used.
The data processing unit sets the control variable u applied to liquid 2 such that the calculated volume of liquid F1 to be dispensed corresponds or basically corresponds with the predetermined volume of liquid to be dispensed that was entered in the first step T1. As the function is an inverse function the data processing unit 9 can easily determine the control variable u.
In a third step T3 the data processing unit 9 acts on the dispensing head 8 such that the determined pressure is applied on the liquid 2. This leads to that liquid is dispensed from the receptacle wherein the dispensed liquid has the volume of liquid to be dispensed that was determined in the second step S2.
26.04.2022 005A0018LU 15
LU501940
Fig. 7 shows a perspective view of a part of a dispensing device 5 for dispensing liquid located in a receptacle 2, wherein the view shows more details of the dispensing device 5 than in the figures land 2.
The dispensing device 5 comprises a dispensing head 8. The dispensing head 8 is configured to dispense liquid located in the receptacle 2. Thereto, the dispensing head 8 has a pneumatic system including one or more valves (not shown in the figure) by means of which at least one receptacle 2 or several receptacles 2 can be provided with an impulse pressure that causes the liquid to drop from the outlet opening 4 of the respective receptacle 2.
Also, the device 5 comprises a holder 6, in which the carrier 7 is mounted in a detachable manner.
The dispensing head 8 is moveable relative to the holder 6 by means of a motor system (not shown in the figure). In particular, the dispensing head 8 can be moved relative to the carrier 7 so that the liquid of different receptacles 2 can be dispensed in sequence. Alternatively or additionally, it is possible that the carrier 7 and/or the holder 6 moves relative to the dispensing head 8.
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LU501940
Reference Signs: 1 liquid 2 receptacle 3 inlet opening 4 outlet opening 5 dispensing device 6 holder 7 carrier 8 dispensing head 9 data processing unit 10 pressure sensor 11 target carrier holder 12 target carrier 13 target receptacle 14 closing element 15 dispensing line 16 seal 17 liquid acquisition device 18 source 19 receiver 23 test receptacle 24 valve pressure source 25 t1 first time t2 second time t3 third time p1 first pressure course p2 second pressure course
S1-S4 method steps of leakage test
T1-T3 method steps of operation mode
T Threshold
Claims (19)
1. Method for determining a leak in a dispensing device (5) for dispensing liquid (1), wherein the dispensing device (5) comprises a dispensing head (8) for applying pressure on a receptacle (2) comprising an inlet opening (3) for inletting liquid (1) into the receptacle (2) and an outlet opening (4) for dispensing liquid (1) from the receptacle (2) when a pressure is applied on the liquid (1), wherein the method comprises the following steps preventing that liquid (1) is dispensed by the dispensing device (5) when a pressure is applied on the liquid (1), applying a pressure on the liquid (5), measuring a pressure applied on the liquid (1) and determining on the basis of the measured pressure whether the dispensing device (5) has a leak.
2. Method according to claim 1, characterized in that a liquid dispensing is prevented by a. closing the outlet opening (4) of the receptacle (2) by a closing element (14) and/or by b. exchanging the receptacle (2) by a test receptacle (23) that comprises an inlet opening for inletting liquid into the test receptacle (23) and a closed bottom.
3. Method according to claim 1 or 2, characterized in that a. a pressure course is determined or in that b. a pressure course is determined during a predetermined time period.
4, Method according to at least one of the claims 1 to 3, characterized in that a valve (24) of the dispensing device (5) is opened in order to apply a pressure on the liquid (1).
5. Method according to claim 4, characterized in that a. the valve (24) is closed after the pressure is applied on the liquid (1) and/or in that b. the valve (24) is closed after the pressure is applied and remains closed during the determination whether the dispensing device (5) has a leak.
6. Method according to at least one of the claims 1 to 5, characterized in that a. it is determined that the dispensing device (5) has a leak, when the measured pressure fulfills a predetermined condition with respect to a predetermined
26.04.2022 005A0018LU 18 LU501940 threshold, in particular whether the measured pressure is below the predetermined threshold within a predetermined time period and/or whether the pressure course is below the predetermined threshold within a predetermined time period, and/or in that b. it is determined that the dispensing device (5) does not have a leak, when the measured pressure fulfills another predetermined condition with respect to a predetermined threshold, in particular whether the measured pressure is above the predetermined threshold within a predetermined time period and/or the pressure course is above the predetermined threshold within a predetermined time period.
7. Method according to at least one of the claims 1 to 6, characterized in that the dispensing device (5) is enabled to dispense liquid (1) when it is determined that the dispensing device (5) does not have a leak.
8. Dispensing device (5) for dispensing liquid (1), in particular for executing a method according to at least one of the claims 1 to 7, wherein the dispensing device (5) comprises a holder (6) for holding a carrier (7) comprising at least one receptacle (2) comprising an inlet opening (3) for inletting liquid (1) into the receptacle (2a, 2b) and an outlet opening (4) for dispensing liquid (1) from the receptacle (2a, 2b) when a pressure is applied on the liquid (1), a dispensing head (8) for providing a pressure on the receptacle (2), a pressure sensor (10) for measuring pressure applied on the liquid (1) and a data processing unit (9) that is configured to determine on the basis of the measured pressure whether the dispensing device (5) has a leak.
9. Dispensing device (5) according to claim 8, characterized in that the dispensing device (5) comprises a valve (24) that in an open position fluidically connects a pressure source (25) and the receptacle (2) and/or that in a closed position fluidically disconnects a pressure source (25) and the receptacle (2).
10. Dispensing device (5) according to claim 9, characterized in that the valve (24) is in the closed position during the determination whether the dispensing device (5) has a leak.
11. Dispensing device (5) according to at least one of the claims 8 to 10, characterized in that the dispensing device (5) is configured such that for the determination whether the dispensing device (5)
26.04.2022 005A0018LU 19 LU501940 has a leak a. a test receptacle (23) with a closed bottom is inserted into the holder or in that b. a closing element (14) is provided that closes an outlet opening of the receptacle (2) that is inserted in the holder (6).
12. Dispensing device (5) according to at least one of the claims 8 to 11, characterized in that the dispensing head (8) has at least one dispensing line (15), wherein the dispensing line (15) has a seal (16).
13. Dispensing device (5) according to claim 12, characterized in that a. the seal (16) is arranged at one end of the dispensing line (15) and/or in that b. the seal (16) is in contact with the receptacle (2) when it is determined whether the dispensing device (5) has a leak and/or in that
C. the pressure sensor (10) is arranged in or on the dispensing line (15).
14. Dispensing device (5) according to at least one of the claims 8 to 13, characterized in that in a dispensing step of the dispensing device (5) the receptacle (2), which has an inlet opening (3) for inletting a liquid (1) into the receptacle (2) and an outlet opening (4) for dispensing liquid from the receptacle (2) when a pressure is applied on the liquid (1), is arranged in the holder (6).
15. Dispensing device (5) according to at least one of the claims 8 to 14, characterized in that a. the dispensing head (8) and the holder (6) are moveable relative to each other and/or in that b. the dispensing line (15) and the receptacle (2) or test receptacle (23) are arrangeable coaxial to each other during the determination whether the dispensing device (5) has a leak and/or in that
C. the dispensing head (8) is moved along a direction that is coaxial or parallel to a length axis of the receptacle (2).
16. Dispensing device (5) according to at least one of the claims 8 to 15, characterized in that the dispensing device (5) comprises a target carrier holder (11) for a target carrier (12) comprising at least one target receptacle (13) for receiving the liquid dispensed from the receptacle (2).
17. Computer program product comprising instructions which cause that a dispensing device
26.04.2022 005A0018LU 20 LU501940 (5), in particular a dispensing device (5) according to at least one of the claims 8 to 16, executes the method steps according to at least one of the claims 1 to 7.
18. Computer-readable data carrier having stored thereon the computer program product of claim 17.
19. Data carrier signal carrying the computer program product of claim 17.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| LU501940A LU501940B1 (en) | 2022-04-26 | 2022-04-26 | Method for determining a leak in a dispensing device for dispensing liquid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| LU501940A LU501940B1 (en) | 2022-04-26 | 2022-04-26 | Method for determining a leak in a dispensing device for dispensing liquid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| LU501940B1 true LU501940B1 (en) | 2023-10-26 |
Family
ID=82358414
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| LU501940A LU501940B1 (en) | 2022-04-26 | 2022-04-26 | Method for determining a leak in a dispensing device for dispensing liquid |
Country Status (1)
| Country | Link |
|---|---|
| LU (1) | LU501940B1 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0571100A1 (en) * | 1992-05-04 | 1993-11-24 | Wallac Oy | Pipette apparatus |
| EP1683577A2 (en) * | 2005-01-20 | 2006-07-26 | Fuji Photo Film Co., Ltd. | Pressurized air supplying mechanism, pressurizing device and extracting apparatus |
| EP3434373A1 (en) * | 2017-07-27 | 2019-01-30 | Eppendorf AG | Pipette device with functional test and method for performing a functional test for a pipette device |
-
2022
- 2022-04-26 LU LU501940A patent/LU501940B1/en active IP Right Grant
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0571100A1 (en) * | 1992-05-04 | 1993-11-24 | Wallac Oy | Pipette apparatus |
| EP1683577A2 (en) * | 2005-01-20 | 2006-07-26 | Fuji Photo Film Co., Ltd. | Pressurized air supplying mechanism, pressurizing device and extracting apparatus |
| EP3434373A1 (en) * | 2017-07-27 | 2019-01-30 | Eppendorf AG | Pipette device with functional test and method for performing a functional test for a pipette device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FG | Patent granted |
Effective date: 20231026 |