Abstract: A pipette device has a coupling stud on which a pipette tip can be stuck in a slipping-on direction for coupling. The coupling stud has an adjustable prestress member that can be adjusted into a prestress state and a release state via an actuation device which is provided in the coupling stud. The pipette tip has an axial stop which interacts with a counter-stop of the coupling stud in an axial coupling position of the pipette tip. The prestress member in its prestress state acts upon a working surface of the stuck-on pipette tip having a surface component of the pipette tip, which extends radially inward, turned away from the stuck on direction, in such a way that it abuts sealingly on the working surface, and prestresses the pipette tip on the pipette unit into the axial coupling position. The prestress member, in its releasing state, substantially releases the working surface of the pipette tip (101).

Abstract: The present disclosure includes a nucleic acid purification apparatus and a pipette, the pipette comprises: a tubular body, at least a gas seal ring, a nut, and a shaft. A first opening and second opening arranged at two ends of the tubular body air communicable with the tubular body, thus forming a main chamber. The gas seal ring is disposed in a seal slot arranged proximate to the second opening. The nut is coupled to the second opening and has portions forming a cavity air communicable with the nut and second opening. An opening has a pressing edge. The shaft can movably dispose in the tubular body and the nut. The pressing edge presses against the gas seal ring via the firm coupling of the nut onto the second opening. As a result, individual adjustment can provide the optimum airtightness in nucleic acid purification devices.

Abstract: The invention relates to a laboratory sample instrument with a cable holding space in which a printed circuit board cable device is arranged. The printed circuit board cable device has at least one printed circuit board with first and second sides and, arranged in succession, at least one first circuit board section, at least one second circuit board section and at least one third circuit board section, and with a number of conductor tracks arranged in parallel with respect to one another and extending from a first track section arranged in the first circuit board section, via the second circuit board section to the third circuit board section, in which a second track section is arranged, wherein, in the second circuit board section, at least one conductor track is arranged on the first side of the board and at least one track is arranged on the second side.

Abstract: A pipette is described which pipette includes a piston for aspirating liquid into and dispensing out of a container in the pipette. The pipette is provided with at least one tracking element, which is able to count the magnitude of some variable or variables relating to the amount of use of the pipette, means for creating a limit magnitude for each variable, and means for giving information when the limit value is exceeded. Thus, the user may, for instance, be warned when he may be exposed to high workload stress possibly causing injuries.

Abstract: The present invention relates to a device for manually metering liquids, for example a pipette or a metering button. The device comprises a joint forming a seal between a hollow cylinder and a piston housed inside the cylinder, the piston being moved vertically so as to suck in or expel the liquid. During the metering operation, the joint remains fixed with respect to the movement of the piston and comprises parts formed by portions having dedicated geometric and mechanical characteristics which make it possible to locally optimize the functions of sliding, sealing and fastening in the cylinder.

Abstract: Syringe for use with a metering device comprising a centring element with an axial through-passage in a receiver for a syringe cylinder and an axially displaceable piston receiver for a syringe piston, comprising syringe cylinder syringe piston, the syringe cylinder comprising an outlet at the bottom, centring flange at the top on the external periphery for inserting into the receiver, cylindrical piston movement area connected to the outlet, with a first internal diameter, in which the syringe piston is sealingly guided, and at least at a distance of at least 3 mm from the upper end of the syringe cylinder a centring region for inserting the centring element, which has a second internal diameter, which exceeds the first internal diameter and is at least 16.2 mm, the syringe piston at the upper end has a coupling piece for inserting into the piston receiver.

Abstract: A handheld electronic pipette including several features aimed at improving ease of use, including a color dot matrix display, an intuitive thumb-operated two-axis controller, and multifunction soft buttons adjacent to the display. A simple and consistent user interface facilitates easy access to various modes of operation, including a manual pipetting mode and a remote mode.

Abstract: The invention relates to a positive displacement sampling pipette (1), comprising a control rod (8) the bottom end (16) of which controls the displacement of a device (20) for gripping the top end (86) of a piston (82) belonging to a capillary-piston assembly (84) intended to cooperate with said pipette, According to the invention, the pipette includes an ejection rod (86) of said capillary-piston assembly, movably mounted with respect to said control rod (8) such that its bottom end (54) can exert an ejection strain on the top end (86) of the piston (82) accommodated in the gripping device (20), during a relative displacement between the ejection rod (46) and the control rod (8).

Abstract: A syringe for use with a dosing device with a receiver for a syringe cylinder and an axially displaceable plunger receiver for a syringe plunger with a syringe cylinder, which has a floor with an outlet on the bottom, a cylindrical plunger run area on the inside and has means for being held in the receiver on the top, a syringe plunger, which has a circumferential plunger seal for sealing on the plunger run area on the perimeter and a coupling piece for insertion into the plunger receiver on the top and stop means between the syringe cylinder and the syringe plunger, which restrict the displacement of the syringe plunger towards the floor so that the syringe plunger with the plunger seal can only approach to a certain distance from the floor.

Abstract: Syringe for use with a metering device comprising a centering element with an axial through-passage in a receiver for a syringe cylinder and an axially displaceable piston receiver for a syringe piston, comprising syringe cylinder syringe piston, the syringe cylinder comprising an outlet at the bottom, centering flange at the top on the external periphery for inserting into the receiver, cylindrical piston movement area connected to the outlet, with a first internal diameter, in which the syringe piston is sealingly guided, and at least at a distance of at least 3 mm from the upper end of the syringe cylinder a centering region for inserting the centering element, which has a second internal diameter, which exceeds the first internal diameter and is at least 16.2 mm, the syringe piston at the upper end has a coupling piece for inserting into the piston receiver.

Abstract: A capillary dispenser includes at least one plunger-cylinder unit having a cylinder module and a plunger module disposed together on an axis. The cylinder module has an inner cylinder that is pneumatically connected to at least one capillary. The plunger module includes a hollow plunger that is closable on one side and is movable in the inner cylinder along the axis between an upper end position and a lower end position of the plunger module.

Abstract: The dispenser includes a dispensing head extending downward from a cylinder body section with a cylindrical inner space and having a dispensing cylinder with the diameter smaller than that of the inner space of the cylinder body section; a piston capable of being inserted from the inner space of the cylinder body section into the dispensing cylinder section and moving up and down between a dispensing start position located in an upper portion of the dispensing cylinder section and a dispensing end position in a lower portion of the dispensing cylinder section; and a sucking mechanism sucking a liquid from a dripping port at a tip of the dispensing cylinder section up to a position above the dispensing start position inside the inner space of the cylinder body section. The piston is always at the dispensing start position under a liquid surface whenever the dispensing operation is started.

Abstract: A reader for mechanical actuation of fluids within a test cartridge. The instrument interface including multiple independently-controlled plungers aligned to respective fluidic pouches on a test cartridge that is inserted into a testing apparatus embodying the instrument interface. The plungers include tips for applying mechanical force to the respective fluidic pouches.

Abstract: The nozzle (3) is in its lower part formed respectively for receiving a pipette exchangeable tip (19) and is in its upper part releasably connected with the holder (2). In the holder (2) a pressure sleeve (6) is placed as being slidably borne in the holder (2). The pressure sleeve (6) is via a pressure sub-assembly seated in the holder (2) pressed to the sealing means placed between the pressure sleeve (6) and the nozzle (3). The plunger (1) is slidably borne in the pressure sleeve (6) and in the pressure sub-assembly. Due to this, leakproofness of the plunger (1) in the nozzle (3), which is indispensable for a correct and reliable pipette operation, is provided in PIPETTING, ADJUSTMENT or CALIBRATION MODES of the pipette. Simultaneously, in MAINTENANCE MODE of the pipette the sealing means automatically slide out from an abutting surface (2c) of the holder (2).

Abstract: An improved metering apparatus includes a metering pipette (1) and a metering attachment (2). The metering pipette (1) includes a metering body (3) and a piston (4) which is longitudinally displaceably guided in the metering body (3). The metering attachment (2) is connected or connectable to the metering pipette (1). It includes a stop body (16) having a stop (17) for the piston (4) (FIG. 2).

Abstract: A device for receiving and dispensing liquids has a plurality of piston-cylinder units (1, 1?, 1?) which are respectively arranged on a piston plate (2) and a cylinder plate (3). The liquid is received and dispensed by displacing the pistons (1?) in the cylinders (1?) by changing the distance between the plates (2, 3), perpendicularly to the plate planes, by means of a drive mechanism (6) and a plate guiding system. The volume can be determined by an upper abutment (4) and a lower abutment (5), at least one of said abutments being regulatable by a regulating means (8). The device is suitable for handling precise volumes of a larger number of piston-cylinder units (1, 1?, 1?) in a technically simple manner.

Abstract: A dispensing device and an analyzer capable of improving dispensing accuracy as well as improving jamming detection accuracy can be realized by having a short distance between a syringe and a suction tip. The dispensing device 10 includes an upper fixed unit 10A, a lower movable unit 10B which is connected to the upper fixed unit 10A, the movable unit being relatively movable with respect to the upper fixed unit 10A, and a Z-axis movement mechanism 55Z which moves the upper fixed unit to and fro. A syringe 4 and a plunger 13 are held by the upper fixed unit 10A. A tip nozzle 8 is attached to the lower movable unit 10B. An interior space of the syringe 4 and an interior space of the tip nozzle 8 are connected with each other by a connection tube 1 having flexibility.

Abstract: A pipette device including a metering liquid receptacle designed to be filled, at least in part, with working fluid and which has a pipette opening as a first tapering of cross-section of flow, a pressure change device which is designed to change the pressure of the working fluid in the metering liquid receptacle, and a throttle point in a pipette duct designed to be filled with working fluid as a further tapering of cross-section of flow. The throttle point is arranged fluid-mechanically between the metering liquid receptacle and the pressure change device and is dimensioned in such a way that a ratio of a flow resistance of the pipette opening for dispensed metering liquid to a flow resistance of the throttle point for working fluid, which flows through the throttle point when the metering fluid is dispensed, is less than 0.5.

Abstract: A pipette for a pipette system comprising a pipette and a syringe. The pipette housing has a longitudinal axis. A syringe to be handled with the pipette is insertable with its fastening portion and plunger head into the pipette housing and is removable or discardable from said pipette housing in the direction of the longitudinal axis of the pipette housing, i.e., axially. The syringe has as cylinder and a plunger with a plunger head which projects out of the end of the cylinder even when the plunger has been completely inserted into the cylinder. A pipette housing comprises an axially accessible plunger gripping device for the plunger head of the syringe. An actuating device for the plunger gripping device is mounted on the plunger displacing device and is axially displaceable with said adjusting device.

Abstract: Pipette for operating a syringe with a bar-shaped housing, a fixture with an opening at the lower end of the housing for putting in a syringe with a fastening portion on the upper edge of a cylinder, a fixture body with a further fixture and a further opening on the lower end of the housing, for putting in a further fastening portion of a piston of the syringe, means for detachably holding the fastening portion in the fixture and the further fastening portion in the further fixture, means for displacing the fixture body within the housing in the longitudinal direction of the housing, which have a draw-up lever activated from the outside of the housing, which is connected to the fixture body via a connection element which grips through a straight slit extending in the longitudinal direction of the housing, wherein below the slit in the housing, a cover stripe covering the slit is held in the housing at two positions spaced apart from each other in the longitudinal direction of the slit, and wherein the connect

Abstract: A pipette for use with pipette tips in which a set metering volume is secured in that the locking body is arranged on the circumference of the annular cylindrical locking element when it is in the locking position. Through this, the transmission part which the locking element comprises on the outer circumference is held fast. The annular cylindrical locking element can be formed separately from a toothed ring for driving a counter mechanism. Thus, it is possible to perform the locking in arbitrary positions or in more selectable rotational positions than in the conventional locking equipment, where a locking element engages into the toothed ring for driving the counter mechanism.

Abstract: A sealing pipette tip includes features to seal the tip directly against the piston in an air displacement pipette, avoiding the need for a piston seal within the pipette. This configuration reduces potential points of failure, allows the pipette-tip interface to be optimized, and improves liquid handling characteristics of the pipette.

Abstract: Provided is a droplet discharging device that can precisely dispense large flow rate of droplets and small flow rate of droplets selectively. The droplet discharging device according to the present invention includes a pneumatic discharger for discharging a droplet having a first flow rate, and an electronic pipette for discharging or sucking a droplet having a second flow rate equal to or smaller than the first flow rate. The pneumatic discharger includes, i) a storage chamber for storing a liquid, ii) an air tank connected to the storage chamber through a first air pipe and supplying compressed air to the storage chamber to push the liquid of the storage chamber outside, and iii) a first nozzle connected to the storage chamber through the liquid pipe and receiving the liquid pushed out of the storage chamber to discharge droplets.

Abstract: A magnetic coupling system may be used in a fluid displacement apparatus to magnetically couple a drive shaft to a piston. The magnetic coupling system may include first and second magnetic couplers at the ends of the drive shaft and piston, respectively. The first magnetic coupler and second magnetic coupler may be configured to exert an attractive force. A bearing between the magnetic couplers reduces friction and side loading.

Abstract: Provided is a pipette, including: a cylinder (1) having a distal end portion (1a) to which a pipette tip (3) is removably fitted; and a piston (7) fitted to be freely advanced and retreated in a cylinder chamber (6), the piston (7) being retreated to suck liquid and advanced to eject the liquid thus sucked. The piston (7) includes, on an outer periphery thereof, a communication groove (17) for communicating an inside of the cylinder chamber (6) and an outside of the cylinder chamber (6) to each other when the piston (7) is advanced by an amount corresponding to a dimension larger than a predetermined dimension, the communication groove (17) being located on the outside of the cylinder chamber (6) when the piston (7) is located at a retreated position.

Abstract: A plunger for a syringe used to inject gas and liquid chromatography samples has an end portion surrounded by a flexible sleeve. The sleeve forms a seal in the bore of a barrel traversed by the plunger, the bore being in fluid communication with a cannula attached to the end of the barrel. The plunger has an end surface that is exposed and is flush with an annular end surface of the sleeve. The plunger end surface, and not the sleeve, contacts the cannula upon injection and avoids imposing cyclical hoop stresses on the barrel which tend to crack the barrel after a finite number of cycles. In a further embodiment, a thin layer of sleeve material covers the end surface of the plunger. The thin layer avoids inducing significant barrel stress.

Abstract: This invention relates to plunger operated liquid dispensers, such as hand held pipettors, which are used to portion liquids. Specifically the invention relates to a reliable removal of a liquid from the liquid dispenser. According to the invention the plunger of the liquid dispenser is arranged into a speeded up movement while removing the liquid. This change in speed is preferably sudden.

Abstract: A handheld electronic pipette including several features aimed at improving ease of use, including a color dot matrix display, an intuitive thumb-operated two-axis controller, and multifunction soft buttons adjacent to the display. A simple and consistent user interface facilitates easy access to various modes of operation, including a manual pipetting mode and a remote mode.

Abstract: The invention relates to a microdispenser (1) for dispensing a liquid sample in a dispensing device, with a sample container (2) for receiving the liquid sample, and with a nozzle (7) for dispensing the sample located in the sample container (2). The microdispenser (1) with the filled sample container (2) can in this case be stored independently of and fluidically separately from the dispensing device, without the sample escaping from the sample container (2) during storage.

Abstract: A pipette core member is used in a pipette for sampling a sample. This pipette core member includes: a pump body including a reservoir communicated with one suction/discharge port of an electroosmotic flow pump, the electroosmotic flow pump and the reservoir being integrally formed; and a capillary connected to the electroosmotic flow pump and communicated with the other suction/discharge port of the electroosmotic flow pump. The capillary is secured to the pump body.

Abstract: A liquid delivery apparatus is provided for depositing liquid materials onto prescribed areas. The apparatus includes a sensing and delivery pin and a photo sensor. The apparatus is sized to deliver a droplet of liquid material to the surface of a target area without coming into contact with the target surface. The apparatus is also capable of drawing geometric features, such as lines and grids of liquid material. The photo sensor measures the intensity of light during a processing cycle. Measured reflected-light intensity can be compared in real-time to a reference curve which is based on test process cycles representing the light intensity expected when the process proceeds in the preferred fashion to produce a normal spot having an expected droplet size. The light intensity measurements can also be fitted with a mathematical function such as an asymmetric double sigmoidal curve.

Abstract: A fluid dispenser useful in automated biological reaction systems comprising a barrel having a reservoir chamber, the barrel having an upper portion and a lower portion, a cap located on top of the upper portion of the barrel and connected to the reservoir chamber, the cap having an external surface with at least one hole therethrough, a valve comprising a biasing member and a hole sealer, the valve being located in the hole in the cap at the point where a downward force is applied against the cap, a coupler having a dispense chamber, the coupler being coaxial with the barrel and wherein the barrel lower portion moves into the dispense chamber during dispensing of fluid, and a vent located between the cap and the reservoir chamber, the vent including a vent opening and a vent material composed of oliophobic material.

Abstract: A hand-held electronic pipettor includes menu driven software for controlling the information displayed on the user interface display, for inputting information to program the pipettor and for controlling the operation of the pipettor.

Abstract: The invention relates to an automatic pipetting device, which comprises at least two pumping units of different capacities and a liquid line, said liquid line opening on one side into a rinsing liquid reservoir and on the other side into a pipetting needle.

Abstract: The invention relates to a functional part of an electronic piston stroke pipette with an operating environment adapted to manual piston stroke pipettes. The piston stroke pipette according to the invention comprises a pipette cone, in which there is a movable piston, rigidly connected with a transmission for its upwards and downwards movements via a piston rod, in which context the transmission is propelled by a drive motor and wherein the control board comprises an upper part as the operating part for turning and pressing and a bar as a cylindrical connection to the electronics, with the control board and display integrated in the display housing in the upper part and drive motor and battery (rechargeable battery) in the lower part of the pipette housing. Fields of application of the invention are analytical chemistry and medicinal diagnostics.

Abstract: A system controls aspiration and dispensation of a liquid in a pipette. The system includes a computing device and the pipette. The computing device includes a pipetting module and a first communication interface. The pipetting module defines an operation to perform at the pipette. The first communication interface sends electronic signals to the pipette, the electronic signals defining the operation to perform at the pipette. The pipette includes a sampling tube, a piston assembly, a piston drive mechanism, a second communication interface, and a microprocessor. The piston assembly mounts to the sampling tube and includes a piston rod that fits within the sampling tube. The piston drive mechanism includes a control rod having a surface that contacts the piston assembly. The piston drive mechanism moves the piston rod of the piston assembly within the sampling tube thereby causing regulation of a liquid in the sampling tube.

Abstract: The invention relates to a two-phase electronic pipette, in which the piston can be moved from the basic position to the lower position and in which the distance between basic position and lower position can be changed.

Abstract: The invention relates to a dispensing cylinder, a large capacity dispensing device, and a method of using a large capacity dispensing device, and aims at providing a dispensing cylinder, a large capacity dispensing device, and a method of using a large capacity dispensing device, with high quantitativity and capable of suppressing the scale of the device and efficiently utilizing working space, despite the relatively large volumes of fluid handled. The construction comprises: a small diameter section, a large diameter section which communicates with the small diameter section and is capable of holding fluids, a sliding section provided in a slidable manner within the large diameter section which enables fluid to be sucked and discharged to and from the large diameter section through the small diameter section, and a connection section which connects the sliding section in a detachable manner to a suction and discharge mechanism which drives the sliding section.

Abstract: An improved metering apparatus includes a metering pipette (1) and a metering attachment (2). The metering pipette (1) includes a metering body (3) and a piston (4) which is longitudinally displaceably guided in the metering body (3). The metering attachment (2) is connected or connectable to the metering pipette (1). It includes a stop body (16) having a stop (17) for the piston (4) (FIG. 2).

Abstract: The invention relates to a method for checking the state of a pipette, which comprises a suction tube and a pipette tip. According to the invention, ultrasound is coupled into the wall of the suction tube and the damping of the ultrasonic signal is measured as a function of the frequency. The measured frequency-dependent damping is compared with at least one reference measurement or a calibration curve based on the reference measurements, in order to determine whether the pipette is in a functional condition and/or whether the pipette contains or has made contact with fluid. Furthermore, the invention relates to a pipetting method, which uses the inventive method for checking the state, a suction tube arrangement for a pipetting device for pipetting fluid and a pipetting device, with which the inventive methods can be carried out.

Abstract: A pipetting device including a pipetting unit (12) having an application chamber (26) and a first end (16) that is realized with a discharge opening (18), and a second, open end (20). In the vicinity of the second, open end (20) of the pipetting unit (12), a sleeve-like receptacle unit (14) is guided so that it can move axially on at least two sealing lips (22, 24) that project radially inward and are at some distance from each other, which is provided on the side facing the application chamber (26) of the pipetting unit (12) with a base element (28), and on the side facing away from the application chamber (26) has an opening (32) and which has, in the vicinity of its periphery, at least one opening (34), the axial dimensions of which are somewhat smaller than or equal to the distance between the sealing lips (22, 24).

Abstract: A method for quantitatively measuring error causing physical parameters in a fluid handling system, includes: measuring the pressure of air between a piston of a pump and a liquid being handled; detecting a pressure abnormality; determining the time at which the pressure abnormality begins to occur; and based on the time of the pressure abnormality determining the magnitude of the physical parameter causing the pressure abnormality. In a preferred embodiment, the error causing physical parameter is a bubble and the fluid handling is an aspirate operation in a diagnostic analyzer.

Abstract: A hybrid manual-electronic pipette combines a manually driven piston with real-time electronic measurement of liquid volume and piston displacement while compensating for both pipette-specific and pipette model-specific variations. The hybrid nature of the pipette facilitates increased accuracy and improved ease of use, and enables additional functionalities not practicable with traditional manual pipettes.

Abstract: A dispensing apparatus includes a syringe which has a piston and sucks and discharges a liquid; and a storage unit which stores therein a reference driving profile indicating a reference of a driving position and a driving time at starting the piston. The apparatus also includes a position detector which detects an actual driving position of the piston; a timer which measures an actual driving time of the piston; and a driving controller which controls driving of the piston based on the reference driving profile, the driving controller creating an actual driving profile based on the actual driving position and the actual driving time of the piston, and the driving controller comparing the reference driving profile with the actual driving profile to determine based on a result of the comparing whether the dispensing is proper or not.

Abstract: A pipette is provided. The pipette includes a body, a piston, and a valve. The body includes a nozzle, a first chamber, a second chamber, and a channel formed in the nozzle. The first chamber is isolated from the second chamber, and the channel is isolated from the first chamber and the second chamber. The piston is mounted to slide within the first chamber and the second chamber so that movement of the piston simultaneously increases a first volume of the first chamber and decreases a second volume of the second chamber. The valve is in communication with the first chamber, the second chamber, the channel, and an exterior of the body to selectively provide a communication between the first chamber and the channel, between the second chamber and the channel, between the first chamber and the exterior of the body, and between the second chamber and the exterior of the body.

Abstract: A positive displacement type substance sampling and dispensing device comprises a central plunger formed from a first material. A plunger housing is formed from a second material having a melting point lower than the first material, the housing being formed by molding and setting the second material on to the surface of the plunger so that the plunger can slide in the housing to draw a substance into it.

Abstract: The invention relates to a pipette, comprising a tip remover element which, upon moving it against a tip, disengages the tip. The remover element is operated with a mechanism, comprising a rotatable ramp member which is provided with a circle-forming ramp surface, including one or more segments within which the ramp surface has a high point and a low point, whereby the ramp surface, upon rotating through a single segment, forces the remover element first to move against the tip and then allows it to return.

Abstract: A pipette including a cylinder part having a cylinder and a tip part, which includes a tip channel connected to the cylinder and a movable piston tightly fit within the cylinder for aspirating liquid into and removing liquid from the tip container attached to the cylinder. In the pipette at least the tip part is made of an elastic material, such as rubber. The tip container can thus be easily and reliably fixed to and removed from the tip container.

Abstract: Pipetting device for metering liquids comprising a piston actuating rod, at least one receiver for a piston head arranged on one end of the piston actuating rod and which is defined by an abutment surface for the piston head in the axial direction of the piston actuating rod, and comprises a through-opening for a piston rod opposing said piston head and a base for supporting the piston head surrounding the through-opening, at least one cylinder with a hollow space, at least one seat for holding a pipette tip, at least one through-channel connecting the hollow space of a cylinder to a through-hole in a seat and at least one piston arranged longitudinally displaceably in a cylinder with a piston rod extending through the through-opening of a receiver and a piston head at the end of the piston rod arranged in the receiver, which is positioned on the base with a lower face facing the piston rod and comprises a resilient body projecting beyond the upper face facing away from the piston rod, which does not bear aga

Abstract: Pipettes, widely used in clinical and pharmaceutical laboratories to transfer small volumes of liquid, may be subject to hidden performance degradation and operator error. Pipette performance cannot be accepted without monitoring. The present disclosure concerns a verification device for a pipette with a piston for aspirating then dispensing, using a shaft, a determined volume of liquid. This device may include: a first assembly for supplying a displaced volume measurement, comparing this measurement to a desired value and generating an indication of the difference between the measured volume and the desired value; and a second assembly, responding to the first assembly, for delivering information relating to the indication.