Patent Publication Number: US-10330693-B2

Title: Cartridge for dispensing a fluid

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 14/530,862, filed Nov. 3, 2014, now allowed, which is a continuation of PCT/EP2012/072733, filed Nov. 15, 2012, which is based on and claims priority to EP 12167108.5, filed May 8, 2012, which is hereby incorporated by reference. 
    
    
     BACKGROUND 
     The present disclosure generally relates to cartridges for dispensing a fluid and an automatic analyzer for dispensing the fluid using the cartridge. 
     In medical laboratories, in vitro diagnostics are commonly performed on biological samples such as blood, urine, blood plasma and saliva. Such tests may be performed manually using pipettes or maybe performed using an automatic analyzer. Automatic analyzers may automatically add reagents to the biological sample and may measure one or more parameters of the biological sample during analysis. 
     SUMMARY 
     According to the present disclosure, a cartridge for dispensing fluid is presented. The cartridge can comprise a valve. The valve can comprise a pumping chamber for pumping the fluid. The valve can position a pumping chamber conduit. The pumping chamber conduit can be connected with the pumping chamber. The cartridge can further comprise a plunger for changing the volume of the pumping chamber and a reservoir conduit for connecting the reservoir with the valve. The valve can position the pumping chamber conduit to connect with the reservoir conduit. Finally, the cartridge can comprise an outlet conduit for dispensing the fluid. The valve can rotate the pumping chamber conduit to connect with the outlet conduit. 
     Other features of the embodiments of the present disclosure will be apparent in light of the description of the disclosure embodied herein. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which: 
         FIG. 1  illustrates a cartridge and an actuator assembly according to an embodiment of the present disclosure. 
         FIG. 2  illustrates how the cartridge may be used to pump fluid through the outlet conduit according to an embodiment of the present disclosure. 
         FIG. 3  illustrates a pumping method similar to that shown in  FIG. 2  except additional steps are performed to remove fluid from the outlet conduit according to an embodiment of the present disclosure. 
         FIGS. 4A-B  illustrate how fluid can be pumped through the outlet conduit where the fluid is taken from the reservoir and then excess fluid from the outlet nozzle and outlet conduit is pumped into the secondary reservoir according to an embodiment of the present disclosure. 
         FIG. 5  illustrates an automatic analyzer according to an embodiment of the present disclosure. 
         FIG. 6  illustrates a bubble guide according to an embodiment of the present disclosure. 
         FIG. 7  illustrates an automatic analyzer according to another embodiment of the present disclosure. 
         FIGS. 8A-D  illustrate the operation of a cartridge using a meniscus detector according to an embodiment of the present disclosure. 
         FIG. 9  illustrates the correlation of the target volume and measured volume for an embodiment of a rotary valve according to an embodiment of the present disclosure. 
         FIG. 10  illustrates a plot indicating the accuracy and the coefficient of variation for the dispensing of fluids of different viscosities and surface tensions by a rotary valve according to an embodiment of the present disclosure. 
         FIG. 11  illustrates a cartridge according to an embodiment of the present disclosure. 
         FIG. 12  illustrates the cartridge of  FIG. 1  connected to an actuator assembly according to an embodiment of the present disclosure. 
         FIG. 13A  illustrates a cartridge according to another embodiment of the present disclosure. 
         FIG. 13B  illustrates a cartridge according to yet another embodiment of the present disclosure. 
         FIG. 14  illustrates the cartridge of  FIG. 2  connected to an actuator assembly according to an embodiment of the present disclosure. 
         FIGS. 15A-B  illustrate views on different phases of the slide valve and plunger of the embodiment shown in  FIG. 1  according to an embodiment of the present disclosure. 
         FIG. 16A-B  illustrate a slide valve and a piston combination according to an embodiment of the present disclosure. 
         FIG. 17  illustrates two views of a slide valve and plunger combination according to another embodiment of the present disclosure. 
         FIGS. 18A-B  illustrate one way of operating the slide valve and piston of the embodiment shown in  FIG. 3  according to an embodiment of the present disclosure. 
         FIG. 19  illustrates an automatic analyzer according to an embodiment of the present disclosure. 
         FIG. 20  illustrates an automatic analyzer according to another embodiment of the present disclosure. 
         FIG. 21  illustrates a cartridge according to another embodiment of the present disclosure. 
         FIG. 22  illustrates an alternative slide valve design according to an embodiment of the present disclosure. 
         FIG. 23  illustrates an alternative slide valve design according to an embodiment of the present disclosure. 
         FIG. 24  illustrates an alternative slide valve design according to an embodiment of the present disclosure. 
         FIG. 25  illustrates an alternative slide valve design according to an embodiment of the present disclosure. 
         FIG. 26  illustrates an alternative slide valve design according to an embodiment of the present disclosure. 
         FIG. 27  illustrates an alternative slide valve design according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description of the embodiments, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration, and not by way of limitation, specific embodiments in which the disclosure may be practiced. It is to be understood that other embodiments may be utilized and that logical, mechanical and electrical changes may be made without departing from the spirit and scope of the present disclosure. 
     A cartridge for dispensing a fluid is presented. In some embodiments, the cartridge can comprise a rotary valve which may be moved in a circular fashion to position a pumping chamber conduit coming from a pumping chamber. Rotation of the rotary valve can enable the pumping chamber conduit to be connected to one of a variety of other conduits. The pumping chamber can be formed by a cavity within the rotary valve and by a plunger which can change the volume of the pumping chamber. In other embodiments, a linear valve can be used for positioning the pumping chamber conduit. 
     The cartridge can comprise a reservoir for storing the fluid and an outlet conduit for dispensing a fluid. A reservoir conduit can connect the reservoir with the valve. In some embodiments, the outlet conduct conduit can connect an outlet nozzle to the valve. As the valve is moved in different positions, the pumping chamber conduit can be positioned at either the reservoir conduit or the outlet conduit. In some embodiments, the valve and the plunger may be able to be operated or actuated independently of each other. Embodiments of this cartridge may have the advantage that they can be operated such that the cartridge does not lose any fluid or that the fluid loss due to priming can be reduced. 
     A controller as used herein can encompass a device, machine, or apparatus for controlling the operation and/or function of one or more other devices. Examples of a controller may include, but are not limited to: a computer, a processor, an imbedded system or controller, a programmable logic controller, and a microcontroller. A ‘computing device’ or ‘computer’ as used herein can encompass any device comprising a processor. A ‘processor’ as used herein can encompass an electronic component which can be able to execute a program or machine executable instruction. 
     A ‘computer-readable storage medium’ as used herein can encompass any tangible storage medium which may store instructions which can be executable by a processor of a computing device. The computer-readable storage medium may be referred to as a computer-readable non-transitory storage medium. 
     ‘Computer memory’ or ‘memory’ can be examples of a computer-readable storage medium. Computer memory can be any memory which can be directly accessible to a processor or other controller. ‘Computer storage’ or ‘storage’ can be examples of a computer-readable storage medium. Computer storage can be any non-volatile computer-readable storage medium. 
     A ‘user interface’ as used herein can be an interface which can allow a user or operator to interact with a computer or computer system. 
     A ‘hardware interface’ as used herein can encompass an interface which can enable a processor or other controller to interact with and/or control an external computing device and/or apparatus. A hardware interface may allow a processor to send control signals or instructions to an external computing device and/or apparatus. The hardware interface may enable the processor or other controller to receive sensor data and control the dispensing of the fluid. The hardware interface may be used to form a closed control loop in some embodiments. 
     A cartridge for dispensing fluid is provided. The cartridge can comprise a valve. The valve can comprise a pumping chamber for pumping the fluid. The valve can position a pumping chamber conduit. The pumping chamber conduit can be connected with the pumping chamber. The valve further can comprise a plunger for changing the volume of the pumping chamber. The valve can further comprise reservoir conduit for connecting the reservoir with the valve. The valve can position the pumping chamber conduit to connect with the reservoir conduit. The valve can further comprise an outlet conduit for dispensing the fluid. The valve can rotate the pumping chamber conduit to connect with the outlet conduit. 
     A cartridge for dispensing fluid is provided. The cartridge can comprise a rotary valve. The rotary valve can comprise a pumping chamber for pumping the fluid. The rotary valve can rotate a pumping chamber conduit. The pumping chamber conduit can be connected with the pumping chamber. In other words, there can be a rotary valve which can have a pumping chamber conduit connected to a pumping chamber within it. By rotating the rotary valve, the pumping chamber conduit can be rotated into different positions thereby allowing the pumping chamber to be connected to other conduits. 
     The cartridge can further comprise a plunger for changing the volume of the pumping chamber. The rotary valve and the plunger can be actuated independently. In other words, the plunger and the rotary valve can be able to be operated such that the plunger can be used to change the volume of the pumping chamber without affecting the position of the rotary valve and vice versa. This may enable a larger set of pumping actions by the pumping chamber. 
     The cartridge can further comprise a reservoir for storing the fluid. The reservoir can be constructed in a variety of ways. In some embodiments, the reservoir may be a hard walled chamber and, in one embodiment, can be made of plastics using injection moulding or thermoforming processes. In some embodiments, the reservoir may be a chamber with a flexible wall. In some embodiments, the reservoir could be a pouch or bladder. In other embodiments, the reservoir can be a pouch or bladder supported by an outer container. In other embodiments, the reservoir can be a tube. 
     The cartridge can further comprise a reservoir conduit for connecting the reservoir with the rotary valve. The rotary valve can rotate the pumping chamber conduit to connect with the reservoir conduit. When the pumping chamber conduit is rotated into the correct position, then there can be communication between the pumping chamber and the reservoir. 
     The cartridge can further comprise an outlet conduit for dispensing the fluid and for connecting to the rotary valve. The rotary valve can further rotate the pumping chamber conduit to connect to the outlet conduit. This embodiment may have the advantage that a large variety of pumping actions can be performed with the pumping chamber by controlling the rotational position of the rotary valve and properly operating the plunger. For instance, the rotary valve may be positioned such that the pumping chamber conduit can be connected to the reservoir conduit. In this case, the plunger may be used to either withdraw fluid from the reservoir into the pumping chamber or may be used to pump the fluid from the pumping chamber back into the reservoir. 
     This embodiment may enable other types of actions using the pumping chamber. For instance, when the pumping chamber conduit is aligned or connected with the reservoir conduit, the plunger may be repeatedly used to increase and decrease the volume of the pumping chamber. This may enable the fluid within the reservoir to be mixed. Also the ability to put the fluid back into the reservoir may reduce the amount of fluid that may be wasted. 
     This embodiment may also enable a so-called reduced waste priming or non-waste priming function of the pumping chamber whereby none or possibly only a very small amount of the fluid may be wasted or discarded when fluid is pumped out through the outlet conduit. For instance, when the pumping chamber conduit is connected with the outlet conduit, the plunger may be used to decrease the volume of the pumping chamber and thereby force or dispense fluid out through the outlet conduit. During the process of doing this, there may be fluid within the outlet conduit which may not exit the outlet conduit. After the correct amount of fluid has been dispensed, the plunger may then be used to increase the volume of the pumping chamber thereby withdrawing fluid that may remain within the outlet conduit back into the pumping chamber. Fluid can then be held within the pumping chamber or if the rotary valve is rotated into alignment with the reservoir conduit the fluid which was previously within the outlet conduit may be pumped back into the reservoir. 
     The rotary valve may also prevent fluid from accidentally leaking from the reservoir. For instance, the rotary valve may be able to be rotated in some embodiments to a position where it is neither aligned with the outlet conduit nor with the reservoir conduit. This may prevent fluid and/or gas from exiting from the outlet conduit and/or from fluid and/or gas in a reservoir leaking or draining into the pumping chamber. 
     In another embodiment, the cartridge can further comprise an outlet nozzle connected to the outlet conduit. An outlet nozzle as used herein can encompass a nozzle design to minimize the waste of fluid and may enable drops to cleanly drip during the dosing process. For instance, in a simple tube, a drop of the fluid may hang outside the nozzle after the plunger is used to decrease the volume of the pumping chamber. The shape or function of the outlet nozzle can be designed to reduce the chances of a drop of the fluid hanging on it. For instance, the outlet nozzle may have a so-called duckbill shape and be a duckbill nozzle. 
     In other embodiments, the cartridge may have additional reservoirs and additional reservoir conduits which can enable the pumping chamber to be connected to these additional reservoirs. Typically, a cartridge may contain only a single fluid or reagent. In some embodiments, this may be a diluent that can be used or required for various tests. There may also be multiple reservoirs which may be each connected to a conduit accessible to the pumping chamber conduit at a particular rotational position of the rotary valve. 
     For example, for many clinical tests, there may be two reservoirs and, for immunoassays, there may be two or three different fluids within different reservoirs. In some embodiments, the cartridge may have multiple pumping units, with each of the pumping units connected to one or more reservoirs via its rotary valve. In this way, the immunoassays can be dispensed using separate pumping units and they may not be mixed by the pumping process. 
     In another embodiment, the cartridge can further comprise a return conduit connected to the reservoir. The pumping chamber conduit can receive fluid from a first portion of the reservoir. The return conduit can return fluid to a second portion of the reservoir. The rotary valve can further rotate the pumping chamber conduit to connect to the return conduit. This embodiment may be beneficial because it may, for instance, reduce the effect of potentially occurring gas bubbles when fluid is returned to the reservoir. This embodiment may further have the benefit of reducing the number of bubbles within the first portion of the reservoir by transmitting the bubbles to the second portion of the reservoir. 
     For instance, fluid can be drawn from the reservoir when the rotary valve can be rotated such that the pumping chamber conduit can be in alignment with the reservoir conduit. After a certain amount of the fluid has been dispensed through the outlet conduit, the rotary valve may be rotated into such a position such that the pumping chamber conduit can be in alignment with the return conduit. The reservoir conduit may draw fluid from one portion of the reservoir and the return conduit can be used to return the fluid to a different portion of the reservoir. For instance, the two locations of the reservoir conduit and the return conduit can be far enough away that it may be unlikely that bubbles which enter the reservoir through the return conduit can be drawn into the reservoir conduit when fluid can be drawn from the reservoir into the pumping chamber. 
     In another embodiment, the cartridge can further comprise a secondary reservoir. The cartridge can further comprise a secondary reservoir conduit. The rotary valve can further rotate the pumping chamber conduit to connect to the secondary reservoir conduit. This embodiment may be beneficial because it may enable a second or distinct fluid to be stored and dispensed using the cartridge, it may also enable waste fluid to be disposed of in the secondary reservoir. 
     It should be noted that additional reservoirs may be added to the cartridge by adding a third reservoir and a third reservoir conduit, a fourth reservoir and a fourth reservoir conduit, and so on so that any number of reservoirs and reservoir conduits may be added to the cartridge. 
     In another embodiment, the cartridge can further comprise a connecting conduit. The connecting conduit can transport fluid between the secondary reservoir and the reservoir. This embodiment may be beneficial because the connecting conduit may enable the secondary reservoir to be used as a place to deposit fluid in order to return it to the reservoir. 
     In another embodiment, the cartridge can comprise a membrane blocking the connecting conduit. The membrane can be permeable to the fluid. This embodiment may be beneficial because it may provide a filtering fluid or blocking of gas bubbles when fluid is returning from the secondary reservoir into the reservoir. 
     In another embodiment, the secondary reservoir can comprise a bubble guiding structure. A bubble guiding structure as used herein can encompass a structure which can be used to guide a gas bubble to a predetermined location in a reservoir or towards a vent. In some implementations, the bubble guiding structure may allow fluid to pass around the bubble as it is moving through the reservoir. For instance, a bubble structure may be a set of ridges which can be used to position and guide a bubble. The structures and ridges may be spaced close enough together such that the surface tension of the fluid can prevent the bubble from going into regions which can allow the fluid to go around the bubble. This may be beneficial because if the bubble is not properly confined, the bubble may get stuck at a particular position in the secondary reservoir and not allowed to go to the top of the secondary reservoir or in the case where there is a connecting conduit to allow the fluid to return to the reservoir. 
     In another embodiment, the reservoir and/or the secondary reservoir can comprise a vent. A vent as used herein can be a structure which can enable air bubbles or other gas volumes to enter or leave the cartridge. Alternatively, the reservoir can comprise such a vent or both the reservoir and the second reservoir can comprise such vents 
     In another embodiment, the vent can be covered or sealed with a filter. The filter can seal the fluid in the cartridge. The filter may be hydrophobic in some embodiments. In some embodiments, the gas filter may have micropores to only let gas through, but no liquids. In some embodiments, the filter may be, but is not limited to: a porous form of polytetrafluoroethylene, carbon fibers, carbon fibers coated with PTFE, carbon nanotubes, polymer fibers, or fluoropolymer fibers 
     In another embodiment, the fluid can comprise magnetic beads, latex beads, a blood grouping reagent, an immune reagent, an antibody, an enzyme, a recombinant protein, a virus isolate, a virus, a biological reagent, a solvent, a diluent, a dispersion, nanoparticles, a protein, a salt, a detergent, a nucleic acid, an acid, a base or combinations thereof. 
     In another embodiment, the fluid may comprise a particles suspension, a liquid reagent, a liquid adhesive, a liquid food product, a liquid metal (e.g., a solder), and/or any other liquid 
     In another embodiment, the cartridge can further comprise a sensor for metering fluid dispensed by the outlet conduit. For instance, this sensor may be a capacitive or optical sensor. 
     In another embodiment, the cartridge can further comprise a coupling assembly for attaching the rotary valve and the plunger to an actuator assembly. This embodiment may be beneficial because it may enable the rotary valve and the plunger to be conveniently connected to an actuator. The coupling assembly in some embodiments may enable the rotary valve and the plunger to be actuated independently by the actuator assembly. 
     In some embodiments, it may be possible to have a cartridge with its own actuator. In this case, the cartridge can further comprise an actuator. In some cases, the actuator may be connected to the coupling assembly or the actuator may be designed or operable for directly actuating the rotary valve and the plunger independently. 
     A pumping unit as used here can encompass the rotary valve and plunger for pumping the fluid. When installed into an automatic analyzer, there may be one actuator per pumping unit or there may be one actuator which can be moved and used to actuate all of the cartridges within the automatic analyzer. In this case, there may be a mechanism for moving the relative positions between the cartridge and the single actuator. There may also be an actuator for a group of cartridges. 
     For example, there may be different configurations for the cartridge. In some embodiments, the cartridge may have a single pumping unit. This single pumping unit may have conduits connected to different reservoirs. This may enable the cartridge to pump different types of fluids from the same cartridge. In another example, the cartridge may have multiple pumping units, with each of the pumping units connected to one or more reservoirs via its rotary valve. 
     In some embodiments, the cartridge can comprise a pumping unit and an attachable reservoir. This embodiment may be beneficial, because a universal pumping unit can be created and reservoirs attached to it when needed. This may facilitate having a larger variety of fluids available. Reservoirs of different volumes may also be selected. Different pumping units may also be selected. Such different pumping units may for instance have plungers with a different stroke and/or diameter. This may affect the volume of the pumping unit. In some applications, it may be desirable to pump a larger volume more accurately and in other applications a smaller but more accurate pumping volume may be desired. So, the use of a pumping unit and an attachable reservoir can allow a modular concept which can allow the combination of reservoirs comprising different types and/or volumes of fluids with an pumping unit which can be optimized to dispense a defined volume of this fluid. This modular concept can provide a large set of optimized cartridges based on a small set of pumping units and/or reservoirs which can be combined in different ways. The assembly of the pumping unit and the attachable reservoir can be performed on the factory site as a manufacturing step during the cartridge production or on the user site, e.g. by assembling the pumping unit with the attachable reservoir before inserting the cartridge into an automatic analyzer. 
     In another embodiment, the rotary valve can comprise a cylindrical portion. The pumping chamber can be a cavity within the rotary valve. The pumping chamber can be formed by the cavity and the plunger. The cartridge can comprise a cartridge body with a cylindrical space for receiving the cylindrical portion. The rotary valve can rotate within the cylindrical space. 
     In another embodiment, the reservoir conduit and the outlet conduit can be located on the cylindrical space. The pumping chamber conduit can be located on the cylindrical portion. 
     In another embodiment, the cartridge can comprise multiple pumping units. 
     In another embodiment, the cartridge can comprise multiple reservoirs. 
     In another embodiment, the multiple reservoirs can be filled with different fluids. 
     An automatic analyzer for analyzing a biological sample is presented. The automatic system can hold a cartridge. The automatic analyzer can comprise an actuator assembly for actuation of the plunger and of the valve. The automatic analyzer can further comprise a controller for controlling the operation of the actuator assembly. 
     An automatic analyzer as used herein can encompass a system for automatically analyzing a biological sample. The automatic analyzer can comprise an actuator assembly for linear actuation of the plunger and for rotational actuation of the rotary valve. The actuator assembly can further actuate the plunger and the rotary valve independently. The automatic analyzer can further comprise a controller for controlling the operation of the actuator assembly. 
     In some embodiments, the automatic analyzer may be adapted for holding multiple cartridges. In this case, there may be a mechanism for providing relative movement between the cartridges and a reaction tube/cuvette. There may be one actuator per pumping unit or there may be one actuator used for multiple cartridges. In this case, there may be a mechanism or a robotic system for providing relative movement between the cartridge and the actuator. There may also be embodiments where there are multiple actuators each used for a group of cartridges. The group of cartridges can be predetermined or the group of cartridges may be determined on the fly. Alternatively, multiple actuators may be used for a cartridge or a group of cartridges, e.g. for different purposes like pre-dispensing or post-dispensing actions. 
     In another embodiment, the automatic analyzer can comprise the cartridge. 
     In another embodiment, the controller can control the actuator assembly to rotate the pumping chamber conduit to connect with the reservoir conduit by rotating the rotary valve. The controller can further control the actuator assembly to fill the pumping chamber by increasing the volume of the pumping chamber with the plunger. The controller can further control the actuator assembly to rotate the pumping chamber conduit to connect with the outlet conduit by rotating the rotary valve. The controller can further control the actuator assembly to pump the fluid through the outlet conduit by decreasing the volume of the pumping chamber with the plunger. This embodiment may be beneficial because it can provide a method of pumping fluid through the outlet conduit. 
     In another embodiment, the controller can control the actuator assembly to receive the fluid from the outlet conduit by increasing the volume of the pumping chamber with the plunger. 
     In another embodiment, the controller can control the actuator assembly to rotate the pumping chamber conduit to connect with the reservoir conduit by rotating the rotary valve. The controller can further control the actuator assembly to return the fluid to the reservoir by decreasing the volume of the pumping chamber with the plunger. This embodiment may be advantageous because it provides operation of the pump without priming. One hundred percent or nearly 100% of the fluid may be used. 
     In another embodiment, the controller can control the actuator assembly to rotate the pumping chamber conduit to connect with the reservoir conduit by rotating the rotary valve. The controller can further control the actuator assembly to mix the fluid in the reservoir by repeatedly increasing and decreasing the volume of the pumping chamber with the plunger. In the case where the fluid contains beads or particles such as, for example, magnetic or latex beads, this embodiment may be used to mix the fluid and its compounds. 
     In another embodiment, the cartridge can comprise an outlet nozzle. The automatic analyzer can further comprise a meniscus detector for detecting a meniscus of the fluid. The controller can control the actuator to force fluid through the outlet nozzle. The controller can further detect the meniscus using the meniscus detector. The controller can further control the actuator to halt the forcing of fluid through the outlet when the meniscus can be in a predetermined location. This embodiment may be beneficial because it may enable more accurate and more precise dispensing of the fluid. This embodiment may be beneficial because if the meniscus is in the same place when the fluid dispensing starts then the dispensing of the fluid may be more accurate, more precise and/or more reproducible. The meniscus may be inside or outside the outlet nozzle. For instance, the outlet nozzle may be a long tube-like structure and the meniscus may have a particular position within the tube. In other embodiments, the meniscus may be formed by a drop of the fluid hanging from the outlet nozzle. In many applications, the meniscus can be positioned right at the orifice of the outlet nozzle. 
     In another embodiment, the controller can further control the actuator to force a predetermined volume of fluid through the outlet. In some embodiments, the actuator may be controlled to force the predetermined volume of fluid through the outlet nozzle after the meniscus is in the predetermined location. 
     In another embodiment, the meniscus detector can be any one of the following: a capacitive sensor, an optical sensor and a camera. When the meniscus is inside of the nozzle, a capacitive sensor may be used to detect the location of the meniscus. In case the nozzle is optically transparent, an optical sensor may also be used to determine the location of the meniscus within the nozzle. If the meniscus extends beyond the nozzle, then a capacitive sensor, an optical sensor or a camera may each be used to determine the location of the meniscus. 
     In another embodiment, the automatic analyzer is operable to hold multiple cartridges. 
     In another embodiment, the automatic analyzer can further comprise the multiple cartridges. 
     The embodiment with the multiple cartridges may be implemented in a variety of ways. For example, each pumping unit may have its own actuator assembly. This may be a parallel operation. In another example, cartridges may be moved and put onto the same actuator assembly or an actuator assembly may be moved between different cartridges or even between different pumping units that can be part of the same cartridge. In other embodiments, there may be multiple actuators and cartridges can be moved via a mechanical robotic system between these multiple actuators. 
     In another embodiment, the automatic analyzer can comprise a sensor or metering system operable for measuring or metering the dispensing of the fluid. The controller can control the dispensing of the fluid in accordance with measurements or data received from the sensor or metering system. In other words, the controller can form a closed loop control system with the sensor or metering system for controlling the dispensing of the fluid. 
     A method of operating a cartridge is presented. The method can comprise rotating the rotary valve to rotate the pumping chamber conduit to connect with the reservoir conduit, increasing the volume of the pumping chamber with the plunger to fill the pumping chamber, rotating the rotary valve to rotate the pumping chamber conduit to connect with the outlet conduit, and decreasing the volume of the pumping chamber with the plunger to pump the fluid through the outlet conduit. 
     In another embodiment, the method can further comprise increasing the volume of the pumping chamber with the plunger to retrieve the fluid from the outlet conduit. 
     In another embodiment, the method can further comprise rotating the rotary valve to rotate the pumping chamber conduit to connect with the reservoir conduit and decreasing the volume of the pumping chamber with the plunger to return the fluid to the reservoir. 
     In another embodiment, the method can further comprise rotating the rotary valve to rotate the pumping chamber conduit to connect with the reservoir conduit and repeatedly increasing and decreasing the volume of the pumping chamber with the plunger to mix the fluid in the reservoir. 
     A cartridge for dispensing fluid is presented. The cartridge can comprise a slide valve. The slide valve can have rectilinear motion. The slide valve may also be referred to as a rectilinear valve. The slide valve can comprise a pumping chamber for pumping the fluid. The slide valve can translate a pumping chamber conduit. The pumping chamber conduit can be connected with the pumping chamber. The cartridge can further comprise a plunger for changing the volume of the pumping chamber. The cartridge can further comprise a reservoir for storing the fluid. The cartridge can further comprise a reservoir conduit for connecting the reservoir with the slide valve. The slide valve can translate the pumping chamber conduit to connect with the reservoir conduit. The cartridge can further comprise an outlet conduit for dispensing the fluid. The slide valve can further translate the pumping chamber conduit to connect with the outlet conduit. This embodiment may be beneficial because the combination of the slide valve and the plunger can allow accurate dispensing of the fluid. Further, the embodiment may also enable a reduced amount of waste fluid produced when dispensing fluid by the cartridge. 
     Embodiments may also have the advantage that a large set of pumping actions by the pumping chamber can be possible. This embodiment may have the advantage that a large variety of pumping actions can be performed with the pumping chamber by controlling the translation position of the slide valve and properly operating the plunger. For instance, the slide valve may be positioned such that the pumping chamber conduit can be connected to the reservoir conduit. In this case, the plunger may be used to either withdraw fluid from the reservoir into the pumping chamber or may be used to pump the fluid from the pumping chamber back into the reservoir. 
     The present embodiment may enable other types of actions using the pumping chamber. For instance, when the pumping chamber conduit is aligned or connected with the reservoir conduit, the plunger may be repeatedly used to increase and decrease the volume of the pumping chamber. This may enable the fluid within the reservoir to be mixed. Also the ability to put the fluid back into the reservoir may reduce the amount of fluid that may be wasted. 
     This embodiment may also enable a so-called reduced waste priming or non-waste priming function of the pumping chamber whereby none or possibly only a very small amount of the fluid is wasted or discarded when fluid is pumped out through the outlet conduit. For instance, when the pumping chamber conduit is connected with the outlet conduit, the plunger may be used to decrease the volume of the pumping chamber and thereby force or dispense fluid out through the outlet conduit. During the process of doing this, there may be fluid within the outlet conduit which may not exit the outlet conduit. After the correct amount of fluid has been dispensed, the plunger may then be used to increase the volume of the pumping chamber thereby withdrawing fluid that may remain within the outlet conduit back into the pumping chamber. Fluid can then be held within the pumping chamber or if the slide valve is translated into alignment with the reservoir conduit, the fluid which was previously within the outlet conduit may be pumped back into the reservoir. 
     The slide valve may also provide a method of preventing fluid from accidentally leaking from the reservoir. For instance, the slide valve may be able to be translated in some embodiments to a position where it can neither be aligned with the outlet conduit nor with the reservoir conduit. This may prevent fluid and/or gas from exiting from the outlet conduit and/or from fluid and/or gas in a reservoir leaking or draining into the pumping chamber. 
     In some embodiments, the cartridge can comprise a pumping unit and an attachable reservoir. This embodiment may be beneficial, because a universal pumping unit can be created and reservoirs attached to it when needed. This may facilitate having a larger variety of fluids available. Reservoirs of different volumes may also be selected. Different pumping units may also be selected. Such different pumping units may for instance have plungers with a different stroke and/or diameter. This may affect the volume of the pumping unit. In some applications, it may be desirable to pump a larger volume more accurately and in other applications a smaller but more accurate pumping volume may be desired. 
     The use of a pumping unit and an attachable reservoir may allow to realization of a modular system which can allow the combination of reservoirs comprising different types and/or volumes of fluids with an pumping unit which can be optimized to dispense a defined volume of this fluid. This modular system may provide a large set of optimized cartridges based on a small set of pumping units and/or reservoirs which can be combined in different ways. The assembly of the pumping unit and the attachable reservoir can be performed on the factory site as a manufacturing step during the cartridge production or on the user site, for example, by assembling the pumping unit with the attachable reservoir before inserting the cartridge into an automatic analyzer. 
     The reservoir can be constructed in a variety of ways. In some embodiments, the reservoir may be a hard walled chamber, preferably made of plastics using injection moulding or thermoforming processes. In some embodiments, the reservoir may be a chamber with a flexible wall. In some embodiments, the reservoir can be a pouch or bladder. In other embodiments, the reservoir can be a pouch or bladder supported by an outer container. In other embodiments, the reservoir can be a tube. 
     In some embodiments, the pumping chamber conduit can be aligned with the reservoir conduit and/or outlet conduit using mechanical stops. As an alternative to using mechanical stops, the alignment can also be achieved by other means, for example, by spatially defined changes of physical or geometrical properties, for example, by changes in friction coefficients or diameter. In other embodiments, mechanical stops may not be used and the alignment can be performed by an actuator system which can be attached to the cartridge during use. 
     In another embodiment, the cartridge can further comprise an outlet nozzle connected to the outlet conduit. An outlet nozzle as used herein can encompass a nozzle design to minimize the waste of fluid and may enable drops to cleanly drip during the dosing process. For instance, in a simple tube, a drop of the fluid may hang outside the nozzle after the plunger is used to decrease the volume of the pumping chamber. The shape or function of the outlet nozzle can be designed to reduce the chances of a drop of the fluid hanging on it. For instance, the outlet nozzle may have a so-called duckbill shape and be a duckbill nozzle. 
     In other embodiments, the cartridge may have additional reservoirs and additional reservoir conduits which can enable the pumping chamber to be connected to these additional reservoirs. Typically, a cartridge may contain only a single fluid or reagent. In some embodiments, this may be a diluent that can be used or required for various tests. There may also be multiple reservoirs which may be each connected to a conduit accessible to the pumping chamber conduit at a particular rectilinear position of the slide valve. 
     For example, for many clinical tests, there may be two reservoirs and, for immunoassays, there may be two or three different fluids within different reservoirs. In some embodiments, the cartridge may have multiple pumping units, with each of the pumping units being connected to one or more reservoirs via its slide valve. In this way, the immunoassays can be dispensed using separate pumping units and they may not be mixed by the pumping process. 
     In some embodiments, the slide valve and the plunger can be actuated independently. In other embodiments, the plunger or the actuation of the plunger can be used to also actuate the slide valve. 
     In another embodiment, the cartridge can further comprise a return conduit connected to the reservoir. The pumping chamber conduit can receive fluid from a first portion of the reservoir. The return conduit can return fluid to a second portion of the reservoir. The slide valve can further translate the pumping chamber conduit to connect to the return conduit. This embodiment may have the benefit of reducing the number of bubbles within the first portion of the reservoir by transmitting the bubbles to the second portion of the reservoir. 
     For instance, fluid can be drawn from the reservoir when the slide valve is translated such that the pumping chamber conduit can be in alignment with the reservoir conduit. After a certain amount of the fluid has been dispensed through the outlet conduit, the slide valve may be translated into such a position such that the pumping chamber conduit can be in alignment with the return conduit. The reservoir conduit may draw fluid from one portion of the reservoir and the return conduit can be used to return the fluid to a different portion of the reservoir. For instance, the two locations of the reservoir conduit and the return conduit can be far enough away that it can be unlikely that bubbles which enter the reservoir through the return conduit are drawn into the reservoir conduit when fluid is drawn from the reservoir into the pumping chamber. 
     In another embodiment, the cartridge can further comprise a secondary reservoir. The cartridge can further comprise a secondary reservoir conduit. The slide valve can further translate the pumping chamber conduit to connect to the secondary reservoir conduit. This embodiment may be beneficial because it may enable a second or distinct fluid to be stored and dispensed using the cartridge, it may also enable waste fluid to be disposed of in the secondary reservoir. 
     In another embodiment, the secondary reservoir can comprise a vent. A vent as used herein can be a structure which can enable air bubbles or other gas volumes to enter or leave the cartridge. Alternatively, the reservoir can comprise such a vent or both the reservoir and the secondary reservoir can comprise such vents. 
     It should be noted that additional reservoirs may be added to the cartridge by adding a third reservoir and a third reservoir conduit, a fourth reservoir and a fourth reservoir conduit, and so on so that any number of reservoirs and reservoir conduits may be added to the cartridge. The additional reservoirs may also comprise vents. 
     In another embodiment, the cartridge can further comprise a connecting conduit. The connecting conduit can transport fluid between the secondary reservoir and the reservoir. This embodiment may be beneficial because the connecting conduit may enable the secondary reservoir to be used as a place to deposit fluid in order to return it to the reservoir. 
     In another embodiment, the cartridge can comprise a membrane or grid or filter located within the connecting conduit. If a membrane is used, the membrane can be permeable to the fluid. Such membranes are described, for example, in “Unimpeded Permeation of Water Through Helium-Leak-Tight Graphene-Based Membranes” (R. R. Nair et al.; Science 335, 442 (2012). If a grid or mechanical filter is used, the mesh or hole size has to be smaller than the gas bubble size to prevent the gas bubbles from transition through the grid or filter. This embodiment may be beneficial because it may provide a means of filtering fluid or blocking of gas bubbles when fluid is returning from the secondary reservoir into the reservoir. 
     In another embodiment, the secondary reservoir can comprise a bubble guiding structure. A bubble guiding structure as used herein can encompass a structure which can be used to guide a gas bubble to a predetermined location in a reservoir or towards a vent. 
     In some implementations, the bubble guiding structure may allow fluid to pass around the bubble as it is moving through the reservoir. For instance, a bubble structure may be a set of ridges which can be used to position and guide a bubble. The structures and ridges may be spaced close enough together such that the surface tension of the fluid can prevent the bubble from going into regions which can allow the fluid to go around the bubble. This may be beneficial because if the bubble is not properly confined, the bubble may get stuck at a particular position in the secondary reservoir and not allowed to go to the top of the secondary reservoir or in the case where there can be a connecting conduit to allow the fluid to return to the reservoir. 
     In another embodiment, the reservoir and/or the the secondary reservoir can comprise a vent. The vent can be sealed with a filter. The filter can be permeable to air. The filter can seal the fluid in the cartridge. The filter may be hydrophobic in some embodiments. In some embodiments, the gas filter may have micropores to only let gas through, but no liquids. In some embodiments, the filter may be, but is not limited to: a porous form of polytetrafluoroethylene, carbon fibers, carbon fibers coated with PTFE, carbon nanotubes, polymer fibers, or fluoropolymer fibers 
     In another embodiment, the fluid can comprise magnetic beads, latex beads, a blood grouping reagent, an immune reagent, an antibody, an enzyme, a recombinant protein, a virus isolate, a virus, a biological reagent, a solvent, a diluent, a dispersion, nanoparticles, a protein, a salt, a detergent, a nucleic acid, an acid, a base or combinations thereof. 
     In other embodiments, the fluid can be a particle suspension, a liquid reagent, a liquid adhesive, a liquid food product, a liquid metal (for example, solder) or any other liquid. 
     In another embodiment, the cartridge can further comprise a sensor for metering fluid dispensed by the outlet nozzle. For instance, this sensor may be a capacitive or optical sensor. 
     In another embodiment, the cartridge can further comprise a coupling assembly for attaching the slide valve and the plunger to an actuator assembly. In some embodiments, the coupling assembly can only attach to the plunger. In other embodiments, the coupling assembly can attach to both the slide valve and to the plunger so that they may be actuated independently. 
     In some embodiments, it may be possible to have a cartridge with its own actuator. In this case, the cartridge can further comprise an actuator. In some cases, the actuator may be connected to the coupling assembly or the actuator may be designed or operable for directly actuating the slide valve and the plunger independently. 
     A pumping unit as used here can encompass the slide valve and plunger for pumping the fluid. When installed into an automatic analyzer, there may be one actuator per pumping unit or there may be one actuator which can be moved and used to actuate all of the cartridges within the automatic analyzer. In this case, there may be a mechanism for moving the relative positions between the cartridge and the single actuator. There may also be an actuator for a group of cartridges. 
     For example, there may be different configurations for the cartridge. In some embodiments, the cartridge may have a single pumping unit. This single pumping unit may have conduits connected to different reservoirs. This may enable the cartridge to pump different types of fluids from the same cartridge. In another example, the cartridge may have multiple pumping units, with each of the pumping units connected to one or more reservoirs via its slide valve. 
     In another embodiment, the cartridge can comprise multiple pumping units or multiple reservoirs. In another embodiment, the multiple reservoirs can be filled with different fluids. 
     In another embodiment, the slide valve can comprise a piston. The pumping chamber can be a cavity within the piston. The pumping chamber can be formed by the cavity and the plunger. The piston can be operable for translational motion within the volume. 
     The piston and the volume may have different cross-sectional shapes which can correspond to each other. For instance, both the piston and the corresponding volume may have a round, oval, or other cross-sectional shape. 
     In another embodiment, the piston and the slide valve can be operable for co-linear motion. In other words, the piston and the slide valve can be operable to have translational motion that can be parallel or in the same direction. 
     In another embodiment, the slide valve can comprises\ a reservoir conduit mechanical stop for aligning the pumping chamber conduit with the reserve conduit. In other words, there can be a mechanical stop which can align the piston such that the pumping chamber conduit can be aligned with the reservoir conduit. 
     In another embodiment, the slide valve can comprise an outlet conduit mechanical stop for aligning the pumping chamber conduit with the outlet conduit. In other words, the slide valve can have a mechanical stop which can align the piston such that the pumping chamber conduit can line up with the outlet conduit. 
     In another embodiment, the piston can comprise two plunger mechanical stops for limiting the motion of the plunger relative to the piston. The plunger can actuate the piston. This embodiment may be beneficial because it can enable the cartridge to be operated with a single linear actuator. This can be particularly true when there can be the combined embodiments of also having a reservoir conduit mechanical stop and an outlet conduit mechanical stop. 
     An automatic analyzer for analyzing the biological sample is presented. The automatic analyzer can hold a cartridge. The automatic analyzer can comprise an actuator assembly operable for linear actuation of the plunger and the slide valve. The actuator assembly may have either one or two actuators depending upon the design of the cartridge. For instance, in some embodiments, the linear actuator may only actuate the plunger. In other embodiments, there may be a linear actuator which can actuate the slide valve and the plunger independently. The automatic analyzer can further comprise a controller for controlling the operation of the actuator assembly. 
     In another embodiment, the automatic analyzer can comprise the cartridge. 
     In another embodiment, the automatic analyzer can hold a cartridge. The piston can comprise two plunger mechanical stops for limiting the motion of the plunger relative to the piston and where the plunger can actuate the piston. The actuator assembly is operable for linear actuation of the plunger. This embodiment may be beneficial because only a single linear actuator is used. The actuation of the slide valve can be done through or by the plunger. 
     In another embodiment, the actuator assembly can be operable for a separate linear actuation of the plunger and for the linear actuation of the slide valve. In this embodiment, there can be two linear actuators in the actuator assembly and the plunger and the slide valve can be actuated independently. This embodiment may be beneficial because it can enable more complex behavior or pumping protocols by the automatic analyzer. 
     In another embodiment, the controller can control the actuator assembly to translate the pumping chamber conduit to connect with the reservoir conduit by translating the slide valve. The controller can further control the actuator assembly to fill the pumping chamber by increasing the volume of the pumping chamber with a plunger. The controller can further control the actuator assembly to translate the pumping chamber conduit to connect with the outlet conduit by translating the slide valve. The controller can further control the actuator assembly to pump the fluid through the outlet conduit by decreasing the volume of the pumping chamber with the plunger. 
     Translating the slide valve can be equivalent herein to translating the piston in those embodiments where the slide valve can have a piston. 
     In another embodiment, the controller can control the actuator assembly to translate the pumping chamber conduit to connect with the reservoir conduit by translating the slide valve. The controller can further control the actuator assembly to return the fluid to the reservoir by decreasing the volume of the pumping chamber with a plunger. This embodiment may be advantageous because it can provide operation of the pump without priming. One hundred percent or nearly 100% of the fluid may be used. 
     In another embodiment, the controller can control the actuator assembly to translate the pumping chamber conduit to connect with the reservoir conduit by translating the slide valve. The controller can further control the actuator assembly to mix the fluid in the reservoir by repeatedly increasing and decreasing the volume of the pumping chamber with the plunger. In the case, where the fluid comprises beads or particles such as, for example, magnetic or latex beads, this embodiment may be used to mix the fluid and its compounds. 
     In another embodiment, the controller can further control the actuator assembly to retrieve fluid from the outlet conduit by increasing the volume of the pumping chamber with the plunger. 
     In another embodiment, the cartridge can comprise an outlet nozzle. The automatic analyzer can further comprise a meniscus detector for detecting the meniscus of the fluid. The controller can further control the actuator assembly to force fluid through the outlet nozzle. The controller can further detect the meniscus using the meniscus detector. The controller can further control the actuator to halt the forcing the fluid through the outlet when the meniscus is in a predetermined location. This embodiment may be beneficial because it may enable more accurate and more precise dispensing of the fluid. This embodiment may be beneficial because if the meniscus is in the same place when the fluid dispensing starts, then the dispensing of the fluid may be more accurate, more precise and/or more reproducible. The meniscus may be inside or outside the outlet nozzle. For instance, the outlet nozzle may be a long tube-like structure and the meniscus may have a particular position within the tube. In other embodiments, the meniscus may be formed by a drop of the fluid hanging from the outlet nozzle. In many applications, the meniscus can be positioned right at the orifice of the outlet nozzle. 
     In another embodiment, the controller can further control the actuator to force a predetermined volume of fluid through the outlet. In some embodiments, the actuator may be controlled to force the predetermined volume of fluid through the outlet nozzle after the meniscus is in the predetermined location. 
     In another embodiment, the meniscus detector can be any one of the following: a capacitive sensor, an optical sensor and a camera. When the meniscus is inside of the nozzle, a capacitive sensor may be used to detect the location of the meniscus. In case the nozzle is optically transparent, an optical sensor may also be used to determine the location of the meniscus within the nozzle. If the meniscus extends beyond the nozzle, then a capacitive sensor, an optical sensor or a camera may each be used to determine the location of the meniscus. 
     In another embodiment, the automatic analyzer can hold multiple cartridges. In another embodiment, the automatic analyzer can further comprise the multiple cartridges. 
     The embodiment with the multiple cartridges may be implemented in a variety of ways. For example, each pumping unit may have its own actuator assembly. This may be a parallel operation. In another example, cartridges may be moved and put onto the same actuator assembly or an actuator assembly may be moved between different cartridges or even between different pumping units that can be part of the same cartridge. In yet another embodiment, there may be multiple actuators and cartridges that can be moved via a mechanical robotic system between these multiple actuators. 
     In another embodiment, the automatic analyzer can hold multiple cartridges. In this case, there may be a mechanism for providing relative movement between the cartridges and a reaction tube/cuvette. There may be one actuator per pumping unit or there may be one actuator used for multiple cartridges. In this case, there may be a mechanism or a robotic system for providing relative movement between the cartridge and the actuator. There may also be embodiments where there can be multiple actuators each used for a group of cartridges. The group of cartridges can be predetermined or the group of cartridges may be determined on the fly. Alternatively, multiple actuators may be used for a cartridge or a group of cartridges, for example, for different purposes like pre-dispensing or post-dispensing actions. 
     In another embodiment, the automatic analyzer can comprise a sensor or metering system for measuring or metering the dispensing of the fluid. The controller can control the dispensing of the fluid in accordance with measurements or data received from the sensor or metering system. In other words, the controller can form a closed loop control system with the sensor or metering system for controlling the dispensing of the fluid. 
     A method of operating the cartridge is presented. The method can comprise translating the slide valve to translate the pumping chamber conduit to connect with the reservoir conduit. The method can further comprise increasing the volume of the pumping chamber with the plunger to fill the pumping chamber. The method can further comprise translating the slide valve to translate the pumping chamber conduit to connect with the outer outlet conduit. The method can further comprise decreasing the volume of the pumping chamber with the plunger to pump the fluid through the outlet conduit. 
     Embodiments descriptive of an automatic analyzer may also be applicable to an automatic system for dispensing fluids. 
     An automatic system for dispensing fluids is presented. The automatic system can hold a cartridge. The automatic system can comprise an actuator assembly for linear actuation of the plunger and of the slide valve. The automatic system can further comprise a controller for controlling the operation of the actuator assembly. In another embodiment, the actuator assembly can be operable for linear actuation of the plunger. In another embodiment, the automatic system can be operable for separate linear actuation of the plunger and for linear actuation of the slide valve. 
     In another embodiment, the cartridge can comprise an outlet nozzle. The automatic analyzer can further comprise a meniscus detector for detecting a meniscus of the fluid. The controller can control the actuator assembly to force fluid through the outlet nozzle; detect the meniscus using the meniscus detector; and control the actuator to halt the forcing of fluid through the outlet when the meniscus is in a predetermined location. 
     Referring initially to  FIG. 1 ,  FIG. 1  illustrates a cartridge  100  and an actuator assembly  102 . The actuator assembly  102  can comprise a linear actuator  104  which can be able to actuate in direction  105 . The actuator assembly  102  can further comprise a rotational actuator  106  able to actuate in the direction  107 . 
     The cartridge  100  can comprise a plunger  108  and a rotary valve  110 . The cartridge  100  can comprise a cartridge body  112  which can have a cylindrical space  116 . In this case, the cylindrical space  116  can be formed by a bearing material. The rotary valve  110  can have at least a cylindrical portion  114  adapted to fit into the cylindrical space  116  of the cartridge body  112 . The rotary valve  110  can have a hollow space which can form a pumping chamber  118  which can be formed by the hollow space and the plunger  108 . The pumping chamber  118  can have a pumping chamber conduit  120  which can be formed in a wall of the rotary valve  110 . The rotary valve  110  can rotate within the cylindrical space  116  to position the pumping chamber conduit  120  at different angular positions. 
     The cartridge  100  can further comprise a reservoir  122  for being filled with a liquid. The cartridge  100  may also comprise a vent for allowing gas to be vented into the reservoir  122 . The cartridge  100  can further comprise a reservoir conduit  124 . The reservoir conduit  124  can provide the reservoir  122  access to the pumping chamber conduit  120  when the pumping chamber conduit is in the correct rotational position. The cartridge  100  can also comprise an optional outlet nozzle  126  for dispensing the fluid. The outlet nozzle  126  can be connected to an outlet conduit  128 . The outlet conduit  128  can allow the pumping chamber  118  to dispense the fluid. The outlet conduit  128  in this embodiment can be connected to the outlet nozzle  126  when the pumping chamber conduit  120  is in the correct rotational position. There can be a coupling assembly  130  which can couple the actuator assembly  102  to the cartridge  100 . The coupling assembly  130  can be designed for being and actuating the piston  108  in the linear direction  105 . The coupling assembly  130  can also be adapted to independently rotate the rotary valve  110 . For instance, there may be grooves cut into the rotary valve  110  and there may be a shape on the coupling assembly  130  which can mate into the groove of the rotary valve  110 . The example shown in  FIG. 1  is only one way in which the rotary valve  110  and the piston  108  may be actuated. Other equivalent mechanisms may also be used to actuate and attach to the rotary valve  110  and the piston  108 . 
       FIG. 2  illustrates four views  200 ,  202 ,  204 ,  206  of the cartridge  100 .  FIG. 2  illustrates how the cartridge  100  may be used to pump fluid through the outlet conduit  128 . In view  200 , the pumping chamber conduit  120  can be aligned with the reservoir conduit  124 . The plunger  108  can be fully depressed and the pumping chamber  118  can have no volume or can be extremely small. In this example, the plunger  108  can be fully depressed. However, fully depressing the plunger  108  may not be a requirement for the operation. In the examples described herein, the relative motion of the plunger is what is relevant. For example, depressing the plunger  108  can cause the volume of the pumping chamber to decrease and this can force the fluid through the outlet conduit. 
     Next in view  202 , the plunger can be withdrawn in direction  208 . This can cause fluid from the reservoir  122  to enter the pumping chamber  118 . Next in view  204 , the rotary valve  110  can be rotated  210  such that the pumping chamber conduit  120  can be aligned with the outlet conduit  128 . The pumping chamber  118  can now be isolated from the reservoir  122 . Next in view  206 , the plunger  108  can be depressed in direction  212  and fluid  214  can exit via the outlet conduit  128 . 
       FIG. 3  illustrates a pumping method similar to that shown in  FIG. 2  except additional steps are performed to remove fluid from the outlet nozzle  126  and the outlet conduit  128 . The same views  202 ,  204  and  206  are again shown. There are three additional views  300 ,  302  and  304  of the cartridge  100  presented. The step according to view  300  can be performed after view  206 . The plunger  108  can be withdrawn in the direction  306  to withdraw fluid from the outlet nozzle  126  in the outlet conduit  128 . In this example, the plunger  108  can be withdrawn enough such that a bubble  208  can form in the pumping chamber  118 . Next in view  302 , the rotary valve  110  can be rotated in direction  310  such that the pumping chamber conduit  120  can be aligned with the reservoir conduit  124 . Finally in view  304 , the plunger  108  can be depressed in direction  312  thereby forcing fluid out of the pumping chamber  118  into the reservoir  122 . In addition, the bubble  308  can also be forced into the reservoir  122 . 
       FIGS. 4A and 4B  shows seven views  400 ,  402 ,  404 ,  406 ,  408 ,  410 ,  412  of a different embodiment of a cartridge  414 . In this embodiment, the cartridge  414  can have a reservoir  122  and a secondary reservoir  416 .  FIG. 4  illustrates how fluid  214  can be pumped through the outlet conduit  128  where the fluid can be taken from the reservoir  122  and then excess fluid from the outlet nozzle  126  and outlet conduit  128  can be pumped into the secondary reservoir  416 . In this cartridge  414 , it can be seen that there can be a connecting conduit  418  between the reservoir  122  and the secondary reservoir  416 . The connecting conduit  418  may not be necessarily present in all embodiments. In some alternative embodiments, there can also be a membrane which can be permeable to the fluid may be placed some place in the connecting conduit  418 . View  400  shows the plunger  108  as being fully depressed and the pumping chamber conduit  120  being aligned with the reservoir conduit  124 . Next in view  402 , the plunger can be withdrawn in direction  420  filling the pumping chamber  118  with the fluid  214 . Next in view  404 , the rotary valve  110  can be rotated such that the pumping chamber conduit  120  can be aligned with the outlet conduit  128 . 
     The rotary valve can be rotated in direction  422 . Next in view  406 , the plunger  108  can be depressed in direction  424  and fluid  214  can be forced out of the outlet conduit  128 . Next in view  408 , the plunger  108  can be withdrawn in the direction  426  to withdraw the fluid  214  that was previously in the outlet conduit  128  and the pumping chamber conduit  120  back into the pumping chamber  118 . Next in view  410 , a rotary valve  110  can be rotated in direction  428  to align the pumping chamber conduit  120  with the secondary reservoir conduit  430 . Finally in view  412 , the plunger  108  can be depressed in direction  432  driving the bubble  308  and the fluid  126  into the secondary chamber  416 . In some embodiments, the secondary chamber  416  may have a vent to atmosphere. In some embodiments, the vent may be covered with a filter which can allow gas to pass but which can keep the fluid  416  from exiting the cartridge  414 . In view  412 , the pumping chamber conduit  120  and the secondary reservoir conduit  430  are shown filled with the bubble  308 . 
       FIG. 5  illustrates an automatic analyzer  500 . This automatic analyzer is shown as having three cartridges  502 ,  502 ′ and  502 ″. There can be an actuator assembly  504  connected to cartridge  502 . There can be an actuator assembly  504 ′ attached to cartridge  502 ′. There can be an actuator assembly  504 ″ attached to cartridge  502 ″. The actuator assemblies  504 ,  504 ′,  504 ″ can actuate the rotary valve and plunger of the cartridges  502 ,  502 ′,  502 ″. The automatic analyzer  500  is shown as having a relative mover  510  which provides relative movement  512  between a reagent container or cuvette  506  and the cartridges  502 ,  502 ′ and  502 ″. The reagent container or cuvette  506  is shown as containing a biological sample  508 . The cartridges  502 ,  502 ′,  502 ″ may be used to add one or more fluids to the biological sample  508 . The automatic analyzer  500  is shown as further comprising a sensor system  514 . The sensor system can comprise one or more sensors for measuring a quantity or a physical or chemical or biochemical property of the biological sample  508 . For example, the sensor system  514  may comprise an nuclear magnetic resonance (NMR) system, an optical transmission or reflectance measurement system, a pH meter, a camera system, a polymerase chain reaction (PCR) apparatus, a Electrochemiluminescence (ECL) apparatus, a spectroscopic measurement system, an electrochemical or an optical sensor, and a chromatography system. The relative mover  510  can also move the reagent container or cuvette  506  to the sensor system  514 . 
     The arrangement of the cartridges  502 ,  502 ′,  502 ″ and the sensor system  514  is representative. In some embodiments, the reagent container or cuvette  506  may remain in a fixed position and the cartridges  502 ,  502 ′,  502 ″ may move. The actuation systems  504 ,  504 ′,  504 ″ and the sensor system  514  are shown as being connected to a hardware interface  522  of a computer system  520 . The computer system  520  can function as a controller for the automatic analyzer  500 . The computer  520  is further shown as comprising a processor  524  which can control the operation and function of the automatic analyzer  500  using the hardware interface  522 . The processor  524  is shown as further being connected to a user interface  526 , computer storage  528  and computer memory  530 . The computer storage  528  is shown as comprising an analysis request  532 . The analysis request  532  can comprise a request to analyze the biological sample  508 . 
     The computer storage  528  is shown as further comprising sensor data  534  received from the sensor system  514 . The computer storage  528  is shown as further comprising an analysis result  536  which can be determined using the sensor data  534 . The computer memory  530  can comprise a control module  540 . The control module  540  can comprise computer executable code which can enable the processor  524  to control the operation and function of the automatic analyzer  500 . For instance, the control module  540  may use the analysis request  532  to generate commands to generate and send to the actuation systems  504 ,  504 ′,  504 ″, the sensor system  514  and the relative movement system  510 . The control module  540  may also generate the analysis result  536  using the sensor data  534 . 
     Various algorithms may be used for controlling the dispensing of the fluid in different embodiments. For instance, the actuator assembly may be controlled by the processor to perform a series of predetermined actions to dispense the fluid. In another example, a sensor or metering system can be integrated into the automatic analyzer to measure the dispensing of the fluid. In this case, an algorithm can use the actuator assembly and the sensor to form a closed loop feedback to accurately control or meter the dispensing of the fluid. 
       FIG. 6  illustrates a bubble guiding structure  600 . The bubble guiding structure  600  may for instance be located within a reservoir or secondary reservoir of a cartridge. The bubble guiding structure  600  can comprise a bubble channel  602  surrounded by various fluid channels  604 . The bubble channel  602  can provide a path for a bubble  606 . The fluid channels  604  can have a space or width  608  which can be narrow enough such that the bubble  606  can be prevented from entering the fluid channel  604  by the surface tension of the fluid. The bubble channel  602  can confine the bubble  606  and can allow the bubble to rise while allowing the fluid  610  to go around the bubble. 
       FIG. 7  illustrates an automatic analyzer  700 . The automatic analyzer  700  is similar to the automatic analyzer  500  shown in  FIG. 5 . The automatic analyzer  700  of  FIG. 7  additionally has a meniscus detector  702 ,  702 ′,  702 ″. Each meniscus detector  702 ,  702 ′,  702 ″ can be positioned adjacent to the outlet nozzle  126 . The meniscus detector  702 ,  702 ′,  702 ″ can each be connected to the hardware interface  522 . This can enable the processor  524  to control the actuator assemblies  504 ,  504 ′,  504 ″ to control the location of the meniscus. This for instance may enable the processor to more accurately and or reproducibly dispense fluid from the cartridges  502 ,  502 ′,  502 ″. 
       FIG. 8  shows  11  views  800 ,  802 ,  804 ,  806 ,  808 ,  810 ,  812 ,  814 ,  816 ,  818 ,  822  illustrates the functioning of a cartridge  100  in conjunction with a meniscus detector  702 . In these examples, the meniscus detector  702  can be an optical sensor. The use of the optical sensor  702  is exemplary. Other types of sensors may also be used. 
     In view  800 , the pumping chamber conduit  120  can be rotated into position such that it can be aligned with the reservoir conduit  124 . The plunger  108  is shown in this view  800  as being fully depressed. The pumping chamber  118  can therefore be extremely small and is not visible in this view  800 . The position of this plunger  108  in this position may not be necessarily required as long as the plunger  108  can still be able to increase or withdraw a reasonable amount of fluid  214  from the reservoir  122 . Next in view  802 , the plunger  108  can be withdrawn to increase the volume of the pumping chamber  118  and draw fluid  214  from the reservoir  122  into the pumping chamber  118 . Next in view  804 , the pumping chamber conduit  120  can be rotated into position such that can be it is aligned with the outlet conduit  128 . 
     In view  806 , the plunger  108  can be depressed which can decrease the volume of the pumping chamber  118 . This can force fluid  214  into the outlet conduit  128  and the outlet nozzle  126 . The plunger  108  can be controlled in accordance with the meniscus detector  702 . When the meniscus  822  reached a predetermined position, the meniscus detector  702  can be used to detect this and the depression of the plunger  108  can be halted. Next in view  808 , the pumping chamber conduit  120  can again be rotated into alignment with the reservoir conduit  124 . In view  810 , the plunger  108  can be withdrawn thereby increasing the volume of the pumping chamber  118  and drying fluid  214  from the reservoir  122 . Next in view  812 , the pumping chamber conduit  120  can be rotated into position so that it can be aligned with the outlet conduit  128 . The pumping chamber  118  can be filled with the fluid and the meniscus  22  can be in the predetermined location. Next in view  814 , the plunger  108  can be depressed forcing fluid out of the outlet nozzle  126 . It can be seen in view  814  that there can still be fluid within the outlet conduit  128  and the outlet nozzle  126 . Next in view  816 , the plunger  108  can be retracted to withdraw the fluid  214  that can be in the outlet conduit  128  and the outlet nozzle  126  back in two the pumping chamber  118 . In view  818 , the pumping chamber conduit  120  can be rotated into position with the reservoir conduit  124 . Then finally in view  820 , the plunger  108  can be depressed forcing the fluid back into the reservoir  122 . A bubble  308  which can be inside the pumping chamber can be forced out of the pumping chamber and into the reservoir  122 . 
       FIG. 9  illustrates the correlation of the target volume and measured volume for an embodiment of a rotary valve comprising a pumping chamber volume of 10 μL.  FIG. 9  shows a plot of the target volume (in μL)  900  vs the measured volume (in μL)  902 . The measured points are connected by a linear fit indicated by the dashed line  904 . For each data point, water was used as the test fluid. The measured volume has been determined using a calibrated scale. Each data point can indicate an average of three trials performed for the same target volume. In each trial or run, the pumping was repeated 24 times. In other words, at each target volume three trials or runs were performed. For each of these three runs, the fluid was dispensed 24 times and averaged. The data shown in  FIG. 9  illustrate both the very high accuracy (small error bars, even for very small target volumes) and linearity (linear fit is very close to the ideal bisector line) over a large range of target volumes which can be achieved by using an rotary valve according to the invention. 
       FIG. 10  shows a plot indicating the accuracy and the coefficient of variation (CV) for the dispensing of fluids by an embodiment of a rotary valve comprising a pumping chamber volume of 10 μL for fluids of different viscosities and surface tensions. The X-axis  1000  indicates the viscosity of 19 different fluids A-S in terms of mPas. The left Y-axis  1002  indicates the surface tension of each of these fluids in terms of mN/m. The plot of viscosity vs. surface tension for each fluid is indicated by the line  1004 . The measured volume has been determined using a calibrated scale. For each fluid, a trial comprising 21 subsequent dispenses of a target volume of 1 μL has been performed. 
     The right Y-axis  1006  indicates the accuracy of the dispensing  1008  (left column, in %) and the coefficient of variation  1010  (right column, in %) for each fluid. 
     The data shown in  FIG. 10  illustrate that the accuracy and reproducibility of dispensing which can be achieved by using an rotary valve according to the invention is very high and (almost) independent of the viscosity and/or surface tension of the fluid which is dispensed: If comparing the accuracy and CV values of the different fluids A-S in consideration of their increasing viscosity (indicated on the X-axis), no effect of the viscosity both on accuracy and CV can be identified. Also, if comparing the accuracy and CV values of the different fluids A-S in consideration of their respective surface tension (shown in  1004  and indicated on the left Y-axis), also no effect of the surface tension both on accuracy and CV can be identified. 
       FIG. 11  shows a cartridge  1100 . The cartridge can comprise a plunger  1108  which can slide within a piston  1114 . The piston  1114  and a volume  1116  can form a slide valve  1110 . The volume  1116  may be formed in a housing  1117  or a portion of the cartridge  1100 . The slide valve  1110  can be capable of rectilinear motion. As the piston moves  1114 , there can be a pumping chamber conduit  1120  that can be moved along with the piston  1114 . There can be a hole within the piston  1114  that the plunger  1108  can move in. This hole in the piston  1114  and the plunger  1108  can form a pumping volume  1118 . 
     The piston  1114  can move the pumping chamber conduit  1120  into different locations. In this view, it is shown as aligned with a reservoir conduit  1124 . The reservoir conduit  1124  can connect a reservoir  1122  filled with a fluid with the pumping chamber  1118 . The reservoir  1122  can be surrounded by a cartridge body  1112 . In this position, the plunger  1134  can be moved such as to increase or decrease the volume of the pumping chamber  1118 . When the plunger  1108  is moved to increase the volume of the pumping chamber  1118  when the piston  1114  is in this location, fluid can be withdrawn from the reservoir  1122 . 
     The piston  1114  can be moved such that the pumping chamber conduit  1120  can be aligned with an outlet conduit  1128 . The outlet conduit  1128  can provide access to an outlet nozzle  1126 . When the pumping chamber conduit  1120  is aligned with the outlet conduit  1128 , the fluid can be expelled from the pumping chamber  1118  through the nozzle  1126  by decreasing the volume of the pumping chamber  1118 . 
     In this embodiment, the piston  1114  is shown as having a first plunger mechanical stop  1130  and a second plunger mechanical stop  1132 . The plunger in this example can have a mechanical extension  1134  that can contact the first plunger mechanical stop or the second plunger mechanical stop. In this embodiment, the entire pumping arrangement may be done only be actuating the plunger  1108 . When the mechanical extension  1134  contacts the first plunger mechanical stop  1130 , the plunger  1108  can push the piston  1114  such that the pumping chamber conduit  1120  can be aligned with the reservoir conduit  1124 . When the mechanical extension  1134  contacts the second plunger mechanical stop  1132 , the plunger  1108  can move the piston  1114  such that the pumping chamber conduit  1120  can be aligned with the outlet conduit  1128 . 
     The first plunger mechanical stop  1130 , the second plunger mechanical stop  1132  and the mechanical extension of the plunger  1134  may not be present in all embodiments. 
     In an alternative embodiment, the cartridge may have a reservoir mechanical stop. The reservoir mechanical stop can contact a contacting surface. This can provide a reservoir mechanical stop that can roughly align the pumping chamber conduit  1120  with the reservoir conduit  1124 . In some embodiments, there may also be an outlet mechanical stop present and corresponding contacting surface for aligning the pumping chamber conduit with the outlet conduit. 
     In an alternative embodiment, an end of the volume  1116  may provide a mechanical stop for aligning the pumping chamber conduit  1120  with the reservoir conduit. For instance, in this example, the volume  1116  can be closed at one end with the exception of an air vent  1140 . The ending surface  1142  may be used in some embodiments as a mechanical stop for the piston  1114  also. 
     In some embodiments, the plunger  1134  may operate in the position of the piston  1114  without the use of the reservoir mechanical stop or even a conduit mechanical stop. For instance, the surface between the piston  1114  and the volume  1116  may be constructed such that it can be more difficult to move piston  1114  than it can be for the plunger  1108 , e.g., because the static friction between the piston  1114  and the volume  1116  can be larger than the static friction between the plunger  1108  and the corresponding hole in the piston  1114 . In this case, the plunger  1108  can be moved without dislocating the piston  1114  unless the plunger  1108  contacts one of the first plunger mechanical stop  1130  or the second plunger mechanical stop  1132 . 
       FIG. 12  shows the cartridge  1100  of  FIG. 11  connected to an actuator assembly  1200 . The actuator assembly  1200  can comprise a linear actuator  1202  which can move along a linear track  1204  in the direction  1206 . The linear actuator  1202  can be connected by a coupling assembly  1208  to the plunger  1108 . 
       FIG. 13A  shows a further example of a cartridge  1300 . The example in  FIG. 13  is similar to that shown in  FIGS. 11 and 12  with several additional features. In this embodiment, there can be a secondary reservoir  1322 . The secondary reservoir  1322  can be connected to a secondary reservoir conduit  1324  which can be aligned with the pumping chamber conduit  1120 . There can be an optional connection for a connecting conduit  1326  between the reservoir  1122  and the secondary reservoir  1322 . In this example, there can also be an optional membrane  1327  covering the surface of the connecting conduit  1326 . The membrane  1327 , for instance, may prevent bubbles from the secondary reservoir  1322  from entering the reservoir  1122 . This structure may, for instance, be useful for pumping fluid  1302  out of the reservoir  1122  and returning unused fluid  1302  to the secondary reservoir  1322 . The reservoir  1122  can have an optional vent  1328  and the secondary reservoir  1322  can have an optional vent  1330 . There can be a side wall  1332  which can divide the reservoir  1122  from the secondary reservoir  1322 . In some embodiments, this dividing wall  1332  may not be present in which case the primary reservoir can form a first portion of the reservoir and the secondary reservoir  1322  can form a second portion of the reservoir. In this example, the plunger  1108  and the piston  1114  can be actuated independently. Such a structure for the plunger  1108  and the piston  1114  may also be used as an alternative to the structure shown in  FIG. 11 . 
       FIG. 13B  shows an alternative example of a cartridge  1350  that is similar to the cartridge  1300  shown in  FIG. 13A . In the embodiment of  FIG. 13B , there can be a separate reservoir  1122 ′and a separate secondary reservoir  1322 ′. The connecting conduit  1326  of  FIG. 13A  is not present. The reservoir  1122 ′ may contain a first fluid  1302  and the secondary reservoir  1322 ′ may contain a second fluid  1302 ′. The first fluid  1302  and the second fluid  1322 ′ may be different fluids. 
       FIG. 14  shows the cartridge  1300  in  FIG. 13  connected to an actuator assembly  1400 . In this embodiment, both the plunger  1108  and the piston  1114  can be actuated independently. There can be a linear actuator  1202  which can move along a linear track  1204  which can be connected to the plunger  1108  by a coupling assembly  1208 . There can be a linear actuator  1402  which can move along linear track  1404  which can be connected to the piston  1114  by a coupling assembly  1408 . Both linear actuators  1202  and  1402  can move in the direction  1206 . The actual implementation of the actuator assembly  1400  is intended to be representative and other actual constructions may be used also. 
       FIGS. 15A and 15B  show five different views  1500 ,  1502 ,  1504 ,  1506 ,  1508  of the slide valve  1110  with a plunger  1108  and piston  1114  of the embodiment shown in  FIG. 11 .  FIGS. 15A and 15B  show an example of how the piston  1114  and plunger  1108  can be used to pump fluid from the reservoir chamber through the outlet nozzle  1126 . In view  1500 , the pumping chamber conduit  1120  can be aligned with the reservoir conduit  1124 . The pumping chamber volume  1118  can be at its minimum volume. The mechanical extension  1134  can be in contact with the first plunger mechanical stop  1130 . Next in view  1502 , the plunger  1108  can be withdrawn in direction  1510 . The plunger can be withdrawn until the mechanical extension  1134  contacts the second plunger mechanical stop  1132 . In this embodiment, the piston  1114  can require more force to move than the plunger  1108 . In other words, the plunger  1108  can slide easier than the piston  1114 . This can be accomplished by designing the plunger  1108  so that it can have less friction than the piston  1114 . This can enable the piston  1114  and the plunger  1108  to use a single actuator. Mechanical stops  1130  and  1132  can be used to restrict the motion of the plunger  1108 . The frictional force on the plunger can cause the plunger  1108  to move first when a linear force is applied to the plunger  1108 . When the plunger  1108  hits a mechanical stop  1130 ,  1132 , then the plunger  1108  and the piston  1114  can move together. 
     The pumping chamber  1118  can be filled with fluid from the fluid reservoir. Next in view  1504 , the plunger  1108  can be withdrawn further. The mechanical extension  1134  can be in contact with the second plunger mechanical stop  1132  so the plunger  1108  can exert force on the piston  1114 . The plunger  1108  can be moved so far such that the piston  1114  can move the pumping chamber conduit  1120  into alignment with the outlet conduit  1128 . Next in view  1506 , the plunger  1108  can be moved in direction  1514 . The fluid can be forced out of the pumping chamber  1118  by the plunger  1108  and through the outlet conduit  1128 . Fluid can exit the outlet nozzle  1126  and can form droplets  1516  exiting the cartridge through the outlet nozzle  1126 . 
     Finally, in view  1508 , the plunger  1108  can be depressed in direction  1518  further such that the mechanical extension  1134  can exert force on the second plunger mechanical stop  1132  to force the piston  1114  to align the pumping chamber conduit  1120  with the reservoir conduit  1124  again. In this embodiment, there can be no mechanical stop to align the piston with the reservoir conduit  1124 . This can most likely be performed by controlling the actuator of the plunger  1108 . View  1508  is substantially the same as view  1500 . In this position, the pumping process can begin again. 
       FIGS. 16A and 16B  illustrate an alternative embodiment to the slide valve  1110  of  FIG. 11 . In the embodiment shown in  FIG. 16A and 16B , the slide valve can comprise a piston  1114  with a plunger  1108 . The operation of this alternative embodiment is also illustrated in  FIGS. 16A and 16B  by views  1600 ,  1602 ,  1604 ,  1606 , and  1608 . In the embodiment shown in  FIGS. 16A and 16B , the linear position of the reservoir conduit  1124  and the outlet conduit  1128  can be reversed with respect to those in  FIG. 15A and 15B . In contrast to the embodiment shown in  FIG. 15A and 15B , the piston  1114  can require less force to move than the plunger  1108 . In other words, the piston  1114  can slide easier than the plunger  1108 . This can be accomplished by designing the plunger  1108  so that it can have more friction than the piston  1114 . As is described below, the mechanical stops  1130 ,  1132 ,  1609  and  1610  in combination with the frictional plunger  1108  can enable pumping to be accomplished with a single actuator. 
     This embodiment can have an outlet mechanical stop  1610  that can align the piston  1114  such that the pumping chamber conduit  1120  can align with the outlet conduit  1128 . This embodiment can also have a reservoir mechanical stop  1609  that is shown as extending out from the slide valve  1110 . The piston can have a contacting surface  1611 . When the contacting surface  1611  contacts the reservoir mechanical stop  1609 , the reservoir conduit  1124  can be aligned with the pumping chamber outlet  1120 . There can also be an outlet mechanical stop  1610  on the slide valve  1110  that can be operable for becoming in contact with contacting surface  1613 . When the outlet mechanical stop  1610  contacts contacting surface  1613 , the pumping chamber conduit  1120  can be aligned with the with the outlet conduit  1128 . 
     In view  1600 , the pumping chamber conduit  1120  can be aligned with the reservoir conduit  1124 . The pumping chamber  1118  can be at its minimum and the contacting surface  1611  of the piston  1114  can be in contact with the reservoir mechanical stop  1609 . The slide valve  1110  is shown as having a first plunger mechanical stop  1130  and a second plunger mechanical stop  1132 . When mechanical extension  1134  is in contact with the first plunger mechanical stop  1130 , then the volume of the pumping chamber  1118  can be at a minimum. When the mechanical extension  1134  is in contact with the second plunger mechanical stop  1132 , then the volume of the pumping chamber  1118  can be at a maximum. 
     The piston  1108  can have its mechanical extension  1134  in contact with the first plunger mechanical stop  1130 . Next in view  1602 , the plunger  1108  can be withdrawn in direction  1612 . The volume of the pumping chamber  1118  can increase and fluid can be withdrawn from the reservoir chamber until the mechanical extension  1134  contacts the second plunger mechanical stop  1132 . The reservoir mechanical stop  1609  can prevent the piston  1114  from moving during this. 
     Next in view  1604 , the piston  1108  can be moved in direction  1614 . The volume of the pumping chamber  1118  can stay the same and the contacting surface  1613  of the piston  1114  can come in contact with the outlet mechanical stop  1610 . This can align the pumping chamber conduit  1120  with the outlet conduit  1128 . 
     Next in step  1606 , the plunger  1108  can be depressed further until the mechanical extension  1134  contacts the first plunger mechanical stop. The piston  1114  can already be in contact with the outlet pumping chamber conduit mechanical stop  1610 . As the plunger  1108  is depressed in direction  1616 , the piston  1114  cannot move any further. The plunger  1108  can then force fluid out of the pumping chamber  1118  through the outlet conduit  1128  and the nozzle  1126 . Droplets of fluid  1516  can form exiting the cartridge. The plunger  1108  can be depressed until the mechanical extension  1134  comes in contact with the first plunger mechanical stop  1130 . 
     Next in step  1608 , the plunger  1108  can be moved in direction  1618 . The plunger can be moved in direction  1618  until the contacting surface  1611  of the piston  1114  contacts the reservoir mechanical stop  1609 . The piston  1114  and plunger  1108  can now be in the same position they were in in view  1600 . The pumping cycle has been completed. This process may be repeated to pump more fluid  1516  out of the cartridge. 
       FIG. 17  shows two views  1700 ,  1702  of a slide valve  1110  and plunger combination  1108  that can be an alternative to that shown in  FIG. 11 . In this embodiment, there can be no mechanical stops and the piston  1114  and the plunger  1108  may be operated independently. In view  1700 , the piston  1114  can be moved such that the pumping chamber conduit  1120  can be in alignment with the reservoir conduit  1124 . Fluid may be pumped into the pumping chamber  1118  by moving the plunger  1108  outwards. Fluid may also be moved back into the reservoir conduit  1124 . For instance, used fluid may be moved back into the reservoir chamber  1124  or the plunger  1108  may be moved in a reciprocating fashion to mix the fluid. View  1702  shows the piston  1114  in a different position such that the pumping chamber conduit  1120  can be in alignment with the outlet conduit  1128 . The piston  1108  can be moved in the direction  1704  to pump fluid through the outlet conduit  1128  and the outlet nozzle  1126  thus forcing droplets  1516  of fluid out of the cartridge. 
       FIGS. 18A and 18B  illustrate one way of operating the slide valve  1110  of the embodiment shown in  FIG. 13 . The method illustrated in  FIGS. 18A and 18B  illustrate how the amount of fluid waste may be reduced during operation. This method is illustrated in eight different views,  1800 ,  1802 ,  1804 ,  1806 ,  1808 ,  1810 ,  1812 , and  1814 . The piston  1114  and plunger  1108  can be operated independently. The method can start in view  1800 . In view  1800 , the pumping chamber conduit  1120  can be aligned with the reservoir conduit  1124 . The plunger  1108  can be in a position where the pumping chamber  1118  can have a relatively small volume. In view  1802 , the plunger  1108  can be withdrawn in direction  1816 . This can cause fluid to be drawn from the fluid reservoir into the pumping chamber  1118 . Next in view  1804 , both the plunger  1816  and the piston  1818  can both be withdrawn simultaneously in direction  1820 ,  1818 . The piston  1114  and the plunger  1108  can both be moved the same amount. They can both be moved until the pumping chamber conduit  1120  is aligned with the outlet conduit  1128 . 
     Next in view  1806 , the piston  1114  can remain in the same position and the plunger  1108  can be depressed  1822 . This can force the fluid out of the pumping chamber  1118  and through the outlet conduit  1128 . This can force the fluid in droplets  1516  out of the outlet nozzle  1126 . 
     Next in view  1808 , to remove fluid remaining within the outlet conduit  1128 , the plunger  1108  can be withdrawn in direction  1824  with the piston  1114  remaining in the same position. The plunger  1108  can be withdrawn  1824  sufficiently such that the majority of fluid can be removed from the outlet conduit  1128 . Also a quantity of air may be withdrawn also forming a bubble  1826 . This can result in a complete emptying of the outlet conduit  1128  from remaining fluids and thereby can avoid the drying of fluid compounds within this outlet conduit  1128 . Due to this complete emptying of the outlet conduit  1128 , no washing or “priming” steps before the next dispensing step can be necessary resulting in a maximum efficiency of the use of the fluid volume within the reservoir. Thus far, the amount of fluid used for cleaning purposes can be reduced; however the presence of a bubble may cause inaccuracies in the dispensing of fluid. 
     Next in view  1810 , to eliminate this problem both the piston  1114  and the plunger  1108  can simultaneously be withdrawn in direction  1830 ,  1832 . Both the piston  1114  and the plunger  1108  can be moved the same amount. They can be moved such that the pumping chamber conduit  1120  can be aligned with the secondary reservoir conduit  1324 . 
     Next in view  1812 , the piston  1114  can remain stationary and the plunger  1108  can be depressed in direction  1834 . This can force the bubble  1826  to the secondary reservoir. This can remove the bubble  1826  from the pumping chamber  1118  and the pumping chamber conduit  1120 . The bubble  1826  can no longer interfere with the proper metering of the fluid in the pumping chamber  1118 . 
     Finally, in view  1814 , both the piston  1114  and the plunger  1108  can be depressed simultaneously in direction  1836 ,  1838  the same amount. The pumping chamber outlet  1120  can again be aligned with the reservoir conduit  1124  and the pumping cycle can be complete. The pump may be used again without the bubble  1826  interfering with the correct measurement or metering of the fluid. 
       FIG. 19  illustrates an automatic analyzer  1900 . This automatic analyzer is shown as having three cartridges  1902 ,  1902 ′ and  1902 ″. There can be an actuator assembly  1904  connected to cartridge  1902 . There can be an actuator assembly  1904 ′ attached to cartridge  1902 ′. There can be an actuator assembly  1904 ″ attached to cartridge  1902 ″. The actuator assemblies  1904 ,  1904 ′,  1904 ″ can actuate the slide valve and plunger of the cartridges  1902 ,  1902 ′,  1902 ″. The automatic analyzer  1900  is shown as having a relative mover  1910  which can provide relative movement  1912  between a reagent container or cuvette  1906  and the cartridges  1902 ,  1902 ′ and  1902 ″. The reagent container or cuvette  1906  is shown as containing a biological sample  1508 . 
     The cartridges  1902 ,  1902 ′,  1902 ″ may be used to add one or more fluids to the biological sample  1908 . The automatic analyzer  1900  is shown as further containing a sensor system  1914 . The sensor system can comprise one or more sensors for measuring a quantity or a physical or chemical or biochemical property of the biological sample  1908 . For example, the sensor system  1914  may comprise a nuclear magnetic resonance (NMR) system, an optical transmission or reflectance measurement system, a pH meter, a camera system, a polymerase chain reaction (PCR) apparatus, a Electrochemiluminescence (ECL) apparatus, a spectroscopic measurement system, an electrochemical or an optical sensor, and a chromatography system. The relative mover  1910  can move the reagent container or cuvette  1906  to the sensor system  1914 . 
     The arrangement of the cartridges  1902 ,  1902 ′,  1902 ″ and the sensor system  1914  is representative. In some embodiments, the reagent container or cuvette  1906  may remain in a fixed position and the cartridges  1902 ,  1902 ′,  1902 ″ may move. The actuation systems  1904 ,  1904 ′,  1904 ″ and the sensor system  1914  are shown as being connected to a hardware interface  1922  of a computer system  1920 . The computer system  1920  can function as a controller for the automatic analyzer  1900 . The computer  1920  is further shown as containing a processor  1924  which can control the operation and function of the automatic analyzer  1900  using the hardware interface  1922 . The processor  1924  is shown as further being connected to a user interface  1926 , computer storage  1928  and computer memory  1930 . The computer storage  1928  is shown as containing an analysis request  1932 . The analysis request  1932  can contain a request to analyze the biological sample  1908 . 
     The computer storage  1928  is shown as further containing sensor data  1934  received from the sensor system  1914 . The computer storage  1928  is shown as further containing an analysis result  1936  which can be determined using the sensor data  1934 . The computer memory  1930  can contain a control module  1940 . The control module  1940  can contain computer executable code which can enable the processor  1924  to control the operation and function of the automatic analyzer  1900 . For instance, the control module  1940  may use the analysis request  1932  to generate commands to generate and send to the actuation systems  1904 ,  1904 ′,  1904 ″, the sensor system  1914  and the relative movement system  1910 . The control module  1940  may also generate the analysis result  1936  using the sensor data  1934 . 
     Various algorithms may be used for controlling the dispensing of the fluid in different embodiments. For instance, the actuator assembly may be controlled by the processor to perform a series of predetermined actions to dispense the fluid. In another example, a sensor or metering system can be integrated into the automatic analyzer to measure the dispensing of the fluid. In this case, an algorithm can use the actuator assembly and the sensor to form a closed loop feedback to accurately control or meter the dispensing of the fluid. 
       FIG. 20  illustrates an automatic analyzer  2000  that is similar to the embodiment shown in  FIG. 19 . The automatic analyzer  2000  is similar to the automatic analyzer  1900  shown in  FIG. 19 . The automatic analyzer  2000  of  FIG. 20  additionally can have a meniscus detector  2002 ,  2002 ′,  2002 ″. Each meniscus detector  2002 ,  2002 ′,  2002 ″ can be positioned adjacent to the outlet nozzle  1126 . The meniscus detector  2002 ,  2002 ′,  2002 ″ can each be connected to the hardware interface  1922 . This can enable the processor  1924  to control the actuator assemblies  1904 ,  1904 ′,  1904 ″ to control the location of the meniscus. This, for instance, may enable the processor to more accurately and/or reproducibly dispense fluid from the cartridges  1902 ,  1902 ′,  1902 ″. 
       FIG. 21  shows a further example of a cartridge  2100 . The cartridge  2100  shown in  FIG. 21  is similar to that shown in  FIG. 11 . The cartridge  2100  shown in  FIG. 21  can comprise two parts. There can be an attachable reservoir  2102  and a pumping unit  2104 . The pumping unit  2104  can have a first connection  2106  and the attachable reservoir  2102  can have a second connection  2108 . The first connection  2106  can connect to the second connection  2108 . This can attach the attachable reservoir  2102  to the pumping unit  2104 . The attachable reservoir  2102  in this example is shown as having a vent  1328 . Near the second attachment  2108 , the reservoir  1122  can be sealed with a seal  2110 . Near the first connection  2106 , there can be a knife edge  2112  that can open the seal  2110  when the first connection  2106  can be connected to the second connection  2108 . 
     The embodiment shown in  FIG. 21  can enable more flexibility and economy in preparing multiple cartridges. For instance, the volume of the attachable reservoir can be varied as well as the type of fluid filling the reservoir  1122 . The pumping unit  2104  may also be varied. For instance, the diameter of the plunger  2108  as well as its stroke can be varied. This may allow for either a more accurate or a high-volume pumping unit to be selected. 
       FIGS. 22 through 25  show various embodiments of the slide valve  1110 . All of the embodiments shown in  FIGS. 22 through 25  show a plunger  1108  with a mechanical extension  1134  on the plunger. The piston  1114  in each of these embodiments can have a first plunger mechanical stop  1130  and a second the plunger mechanical stop  1132  as is described in  FIG. 11 . 
     The embodiment of the slide valve  1110  shown in  FIG. 22  may not have air vent  1140 . There can also be no reservoir mechanical stop or outlet mechanical stop. Precise alignment of the pumping chamber conduit  1120  with the reservoir conduit  1124  or outlet conduit  1128  may be done or provided by an actuator. 
     In  FIG. 23 , the slide valve  1110  is shown as comprising an air vent  1140  as is shown in  FIG. 11 . The slide valve  1110  is shown as comprising a reservoir mechanical stop  1609  for contacting a surface  1611  of the piston  1114 . The reservoir mechanical stop  1609  can align the pumping chamber conduit  1120  with the reservoir conduit  1124 . However, there can be no mechanical stop which can align the outlet conduit  1128  with the pumping chamber conduit  1120 . Precise alignment of the pumping chamber conduit  1122  the outlet conduit  1128  may be done by a linear actuator. 
     In  FIG. 24 , an air vent is not shown. In  FIG. 24 , the slide valve  1110  can comprise an outlet mechanical stop  1610  for contacting a surface  1613  of the piston  1114 . The outlet mechanical stop  1610  can align the outlet conduit  1128  with the pumping chamber conduit  1120 . However, there can be no mechanical stop for aligning the pumping chamber conduit  1120  with the reservoir conduit  1124 . Precise alignment of the reservoir conduit may be provided by a linear actuator. 
     In  FIG. 25 , an air vent  1140  is shown. The embodiment shown in  FIG. 25  can comprise a reservoir mechanical stop  1609  for contacting a surface  1611  of the piston  1114 . The reservoir mechanical stop  1609  can align the pumping chamber conduit  1120  with the reservoir conduit  1124 . The embodiment shown in  FIG. 25  also shows an outlet mechanical stop  1610  on the slide valve  1110 . The outlet mechanical stop  1610  can contact the cut surface  1613  of the piston  1114 . The outlet mechanical stop  1610  can align the pumping chamber conduit  1120  with the outlet conduit  1128 . 
     The examples shown in  FIGS. 22 through 25  are intended to be exemplary and are not all possible combinations of how the slide valve  1110  could be constructed. For example, the relative position of the reservoir conduit  1124  and the outlet conduit  1128  can be juxtaposed linearly. 
       FIGS. 26 and 27  illustrate how the friction between the plunger  1108  and the piston  1114  may be increased. In  FIG. 26 , the slide valve  1110  is shown as having a vent  1110  as is shown in  FIG. 11 . The slide valve  1110  can further comprise a reservoir mechanical stop  1610  and an outlet mechanical stop  1609  for contacting the piston  1114 . As described previously, these mechanical stops  1609 ,  1610  can serve to align the pumping chamber conduit  1120  with the reservoir conduit  1124  and the outlet conduit  1128 . The plunger  1108  is shown as having the mechanical extensions  1134 . However, in the embodiment shown in  FIG. 26 , there can be no first plunger mechanical stops  1130  or second plunger mechanical stops  1132  as has been previously shown. The mechanical extensions  1134  can contact a surface  2600  within the piston  1114 . The contacting mechanical extension  1134  and the surface  2600  can increase the friction between the plunger  1108  and the piston  1114 . This can enable the piston  1114  to be actuated by motion of the plunger  1108 . As there are no plunger mechanical stops, the movement of the plunger  1108  can be controlled by a linear actuator. 
       FIG. 18  shows an embodiment of a slide valve  1110  similar to that shown in  FIG. 26 . The embodiment shown in  FIG. 27  is similar to that shown in  FIG. 26  except with the addition of a first plunger mechanical stop  1130  and a second plunger mechanical stop  1132  for limiting the travel of the plunger  1108  relative to the piston  1114 . Mechanical extensions  1134  can still contact a surface  2600  which can increase the friction between the plunger  1108  and the piston  1114 . This can enable the piston  1114  to be actuated by the plunger  1108 . 
     It is noted that terms like “preferably,” “commonly,” and “typically” are not utilized herein to limit the scope of the claimed embodiments or to imply that certain features are critical, essential, or even important to the structure or function of the claimed embodiments. Rather, these terms are merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the present disclosure. 
     Having described the present disclosure in detail and by reference to specific embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the disclosure defined in the appended claims. More specifically, although some aspects of the present disclosure are identified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these preferred aspects of the disclosure.