Abstract:
An apparatus for dispensing substances, specifically powders and liquids, into a container, is designed as a compact module containing a weighing device with a load receiver, a holder device which is attached to the load receiver and serves to receive and loosely hold the container while the substances are dispensed into the container, and a liquid-dispensing device for dispensing a liquid into the container while the latter is seated in the holder device. The apparatus includes a clamping device for firmly gripping and immobilizing the container, so that a capping device that is not part of the apparatus can put a cap on the container or remove the cap from the container while the latter is seated in the holder device.

Description:
RELATED APPLICATIONS 
   This application is based on and claims priority to European Application No. 04293116.2, filed Dec. 23, 2004, the entire content of which is hereby incorporated by reference. 
   BACKGROUND INFORMATION 
   An apparatus as well as a method are disclosed for dispensing substances, specifically powders and liquids, from a delivery device into a recipient container, particularly into a test tube while the container is resting on the load receiver of a weighing device, specifically a balance. The weighing device can weigh the container for example before and after the dispensing of the substance and/or continuously during the dispensing of the substance into the container. After the substance or substances have been dispensed into the container, the latter may be closed with a cap. 
   An automated laboratory system is also disclosed that includes an apparatus or works according to a method consistent with the foregoing general description. 
   An apparatus and method for transferring and weighing powder materials is described in U.S. Pat. No. 6,674,022 B2. A robotic handling system uses a vacuum to draw a quantity of powder from a source container into a pipette-like transfer device, then moves the transfer device to a recipient container on a balance and drops the powder into the recipient container by switching off the vacuum and/or applying a small amount of pressure to the transfer device. The delivery of powder may include several transfers of partial quantities. The weight of the container is continuously monitored to automatically terminate the powder transfer when the target weight has been reached. 
   An automatic gravimetric sample-processing system for radioactive substances such as plutonium is described in FR 2 610 111 A1. Arranged inside a glove box, the system includes a sampling device, a diluting device, an electronic balance, and a remote-controlled robot arm. In the normal operating cycle, the robot arm picks up an empty recipient vessel from a turntable and places it on the balance, where the tare weight of the empty vessel is determined. The sampling device takes a sample of a liquid substance to be tested and adds it to the vessel on the balance which performs another weighing to determine the weight of the substance sample. Next, the diluting device adds a diluent to the sample in the container on the balance. After the balance has weighed the diluted sample in the container, the latter is returned to the turntable which then advances the container to a stirring device. 
   A fill-weighing system for a pharmaceutical production line is disclosed in EP 0 408 822 A2. Empty vessels such as vials or ampoules arriving on a conveyor device are weighed on a first balance, from where they are transferred to a filling machine to be filled with a powdery or liquid product. The filled containers are transferred to a second balance to determine or verify the correct fill weight, whereupon the filled containers leave the system to proceed to further process steps down the line. A very similar fill-weighing system is also described in U.S. Pat. No. 5,038,839. 
   With regard to the concepts of adding an inert gas and closing the container with a cap, a method and apparatus for sealing containers with food products such as fruit juice under an inert gas atmosphere are described in WO 94/25347 A1. Before capping, the container is put in an enclosed environment where the air is removed and an inert gas is added. Consequently, any space that is not occupied by product will be filled out by the inert gas. 
   In spite of their merits for the specific applications that they were proposed and designed for, the aforementioned known devices fail to address certain requirements that occur especially in the field of laboratory automation. In particular, each of the aforementioned known devices for dispensing substances into containers is designed to work in a set mode and to perform a specific task but lacks the adaptability that is required for automated laboratory applications, in particular the capability to work with a laboratory robot. 
   SUMMARY 
   The present invention therefore has the objective to provide an apparatus for dispensing substances, particularly liquids and/or powders, into containers, which is configured as a module that can operate as a part of an automated laboratory system, particularly with a robot, and which is flexibly adaptable and expandable to perform additional functions. 
   A method is also disclosed for dispensing substances involving the use of the inventive apparatus. 
   An automated laboratory system is disclosed in which the inventive dispensing apparatus cooperates with a laboratory robot. 
   An apparatus for dispensing substances, specifically liquids and powders, into a container, particularly into a test tube that can be closed with a cap, includes a weighing device with a load receiver. Attached to the load receiver is a holder device that serves to receive the container from a handling device and loosely hold the container while the substances are being dispensed into the container. The apparatus further includes a dispensing device for dispensing the substances into the container while the container is seated in the holder device. According to the invention, the apparatus is distinguished in particular by a clamping device which is likewise arranged inside the housing and can be activated to firmly grip and immobilize the container, so that an external capping device which is not part of the apparatus per se can put a cap on the container or remove the cap from the container while the container is seated in the holder device. As a further distinguishing feature of the invention, the apparatus is configured as a compact module with a housing that contains at least the weighing device, the holder device, and the clamping device. The holder device holds the container in a position where only the top ends of the holder device and of the container with a fill opening protrude through a window in the top surface of the apparatus housing. The window has sufficient clearance from the holder device and/or the container to avoid any contact that would interfere with the weighing of the container on the weighing device. 
   An exemplary embodiment including a clamping device in the dispensing apparatus has several advantages, particularly in applications where the containers are closed with a cap after a substance has been dispensed into them by the apparatus according to the invention. Putting a cap on a container such as a test tube or a flask generally requires the use of two human hands or, analogously, two mechanical devices of an automated laboratory system. One hand, or a manipulating device such as a robotic arm, serves to pick up a cap from a cap storage device and to push or screw the cap on the container, while the other hand or a clamping device serves to keep a firm grip on the container, counteracting the force or torque applied by the first hand or by the manipulating device when putting the cap on the container. With the apparatus according to the invention, this capping operation can be performed in an automated system without having to move the container from a dispensing/weighing device to a separate clamping device in order to put on a cap. While simplifying the system and saving space, the inventive concept of integrating the clamping device in the dispensing apparatus also minimizes the time interval between dispensing and capping. This is a particularly important consideration if the dispensed substance is, e.g., a volatile liquid that gives off toxic vapors, or if the dispensed substance is hygroscopic substance, or if it interacts in any other ways with the ambient atmosphere. Also, capping the container before picking it up and moving it to another location reduces the risk of spilling the dispensed substance in case of a system malfunction or operator error. 
   In preferred embodiments of the inventive apparatus, the holder device has lateral window openings and the clamping device has jaws that contact and grip the container through the lateral window openings while the capping device puts the cap on the container or removes the cap from the container. In a rest position of the clamping device, the jaws are retracted from the container and the holder device so that they don&#39;t interfere with the weighing of the container on the weighing device. 
   Preferably, the holder device has a resilient attachment to the load receiver and mechanical stops that limit the movement of the holder device, so that the weighing device is protected from vertical extraneous forces other than a weight within a range that can be measured by, or is at least not harmful to, the weighing device. 
   In a preferred arrangement according to the invention, the module of the foregoing description is mounted by itself on a freestanding pedestal in order to isolate the sensitive weighing system as much as possible from mechanical shocks and vibrations. 
   In an advantageous embodiment of the invention, the apparatus of the foregoing description is further equipped with a suction device for drawing off vapors given off from volatile substances as they are being dispensed into the container while the latter is seated in the holder device on the load receiver of the weighing device. 
   An exemplary apparatus according to the invention can further include a gas-delivery device for dispensing an inert gas into the container while the latter is seated in the holder device on the load receiver of the weighing device. This embodiment is particularly advantageous if the substance dispensed is a hygroscopic substance, or if it interacts in any other ways with the ambient atmosphere, as the inert gas will form a barrier between the substance in the container and the ambient atmosphere. 
   In an advantageous embodiment of the apparatus, the liquid-dispensing device and/or the suction device and/or the gas-delivery device is arranged in a substantially horizontal dispenser arm and includes orifices or dispensing tips at the end of conduits that are connected to sources of liquid and/or powder, vacuum and inert gas. The dispenser arm is movable vertically up and down as well as rotatable about a vertical axis, so that the arm can move between a working position where the dispensing tips are lowered into the container that is seated in the holder device and a parked position where the arm is moved out of the way to allow access to the container from above. The dispenser arm is moved to the parked position to provide access to a device that is not part of the inventive apparatus for example a handling device that places a container in the holder device and removes the container from the holder device, or a further powder-delivery device of a powder delivery module that dispenses a powdery or granular substance into the container, or the aforementioned capping device which can put a cap on the container or remove a cap from the container. 
   Advantageous embodiments of the inventive apparatus may further include an ionizing device for ionizing the atmosphere surrounding the container while the latter is seated in the holder device in order to prevent a build-up of static charges on the container which could cause weighing errors due to electrostatic static forces acting on the container. 
   The apparatus according to the invention may further include a barcode reader for reading bar-coded information that may be affixed to the container. 
   In advantageous embodiments of the inventive apparatus, the aforementioned devices such as the weighing device, the clamping device, the liquid-dispensing device and/or powder delivery device, the gas-delivery device, the suction device, the dispenser arm and/or the barcode reader perform their respective functions under the command of a control device such as a laboratory computer which simultaneously controls external devices that cooperate with the inventive apparatus, such as the aforementioned handling device, and/or the capping device, an/or the further powder delivery device of the powder delivery module, that may work as an alternative or an additional powder delivery device. 
   The scope of the invention further includes a method for dispensing substances, specifically powders and liquids, into a container, particularly into a test tube that can be closed with a cap. The method has the following principal steps: 
   A handling device such as, e.g., a laboratory robot picks up a container from a holding rack and puts the container into a holder device that is supported on the load receiver of a weighing device. A liquid-dispensing device or a powder-delivery device is moved to a position above the container, and a liquid or powder is delivered into the container either by volume as determined by the delivery device, or by weight as determined by the weighing device. The inventive method is in particular distinguished by the fact that a capping device seals the container by pushing or screwing a cap onto the container while the latter is still seated in the holder device and that during the capping operation the container is immobilized and held in a firm grip by a clamping device. Subsequently, the clamping device releases its grip on the container, and the handling device removes the container from the holder device. 
   The scope of the invention includes in particular any method that includes the use of the inventive apparatus in any of the embodiments described herein. 
   An automated laboratory system according to the invention includes in particular the apparatus of the foregoing description in any of the embodiments described herein. 
   In the automated laboratory system, the apparatus according to the invention would typically cooperate with a laboratory robot which may be equipped and programmed to perform functions such as transporting the container to and from the inventive apparatus module as well as picking up a cap and pushing or screwing it onto the container while the latter is held in a firm grip by the clamping device. The automated laboratory system may further include a powder-dispensing module that serves to dispense powdery or granular substances from a suitable delivery device into the container while the latter is seated in the holder device of the inventive apparatus. 

   
     DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention will be further described below with reference to the drawings, wherein: 
       FIG. 1  represents a schematically simplified perspective view of the dispensing apparatus according to an exemplary embodiment of the invention; 
       FIG. 2  represents the apparatus of  FIG. 1  with one sidewall removed and the dispenser arm swiveled over the sample container; 
       FIG. 3   a  represents a side view of the clamping device and the holder device of  FIG. 2 ; 
       FIG. 3   b  represents a top view of the clamping device and the holder device of  FIG. 2 ; 
       FIG. 4  represents a schematic top view of an automated laboratory system that includes the dispensing apparatus according to an exemplary embodiment of the invention; 
       FIG. 5   a  represents a detail of  FIG. 4  in a first side view; 
       FIG. 5   b  represents a detail of  FIG. 4  in a second side view; and 
       FIG. 6  represents a powder container with a dispensing head suitable for use in the automated laboratory system of  FIG. 4 . 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows a schematically simplified perspective view of a preferred embodiment, where the inventive apparatus  1  is configured as a compact module with a substantially box-shaped apparatus housing  2  with one end wall  3 , one sidewall  4 , and a top surface  5  facing the viewer. The dispenser arm  6  is shown in the parked position, so that the top of the holder device  7  which protrudes from the window opening  8  in the top surface  5  is accessible for example to allow a robot arm (not shown) to grip the top of the test tube  9  (shown protruding from the holder device  7 ) and to lift it out and remove it from the apparatus  1 . The dispenser arm  6 , driven by an actuator device (not shown) inside the housing  2 , can move up and down (arrow A) as well as swivel (arrow B) on its support post  10 . An ionizing device  11  is arranged on top of the housing  2  to ionize the ambient air surrounding the test tube  9  in the holder device  7  and thereby to prevent the accumulation of electrostatic charges on the test tube  9  and holder device  7 . The apparatus  1  rests or is mounted on a mounting plate  12  supported by a freestanding pedestal column  13  which stands directly on the floor, independent of other parts of an automated laboratory system  101  (see  FIG. 4 ) that includes the inventive apparatus  1  as one of its components. Shocks and vibrations originating from the other parts of the system  101  are thus prevented from propagating directly to the sensitive weighing device  22  (see  FIG. 2 ) inside the housing  2 . As the apparatus contains the weighing device  22 , it is equipped in the customary manner with a spirit level  14  and level-adjusting feet  15  (only one of which is shown in the drawing). 
     FIG. 2  represents a side view of the same embodiment as shown in  FIG. 1 , with the side wall  4  taken off. The reference symbols used in  FIG. 1  are likewise applicable to  FIG. 2 . The dispenser arm  6  is shown in the working position. From the parked position shown in  FIG. 1 , the dispenser arm  6  has been swiveled over the test tube  9  and then moved downwards so that a liquid-dispensing tip  16  and/or a gas-delivery orifice  16   a  in the dispenser arm  6  is lowered to its dispensing position in the test tube  9 . The dispenser arm  6  contains inside a dispenser arm housing  17  a connector conduit  18  from the flexible liquid-supply conduit to the liquid-dispensing tip  16 . In addition to the dispensing tip  16  and the connector conduit  18  which serve to deliver liquid to the test tube  9 , the dispenser arm  6  can also be equipped with a gas-delivery orifice  16   a,  connector conduit for gas  18   a  and a flexible gas-supply conduit (not shown) to deliver an inert gas, for example argon, to the test tube  9 . The purpose of the inert gas is to separate the substance in the test tube  9  from the ambient atmosphere, for example to prevent the substance from absorbing moisture or from oxidizing. At least in the area above the test tube  9 , the dispenser arm housing  17  is open at the bottom so that it covers the top of the test tube  9  like a fume hood. At the opposite end from the dispenser tips  16 ,  16   a,  the dispenser arm housing is connected to a suction conduit  19  to remove any vapors that may be given off by substances in the test tube  9 . 
   Also shown in  FIG. 2  is the clamping device  20  with one of the clamping jaws  21  extending in front of the holder device  7 . The weighing device  22  is arranged in a separate weighing device compartment  24  which is partitioned by a horizontal plate  30  from the rest of the interior of the apparatus housing  2 . The horizontal plate  30  has an opening in the area where the holder device  7  is seated on the load receiver  23  of the weighing device  22 . 
     FIG. 3   a  shows the clamping device  20  and the holder device  7  with a test tube  9  in an enlarged detail view seen from the same direction as in  FIG. 2 . The clamping jaws  21  (one of which is visible) grip the test tube  9  through windows  25  (one of which is visible) in the holder device  7 . As further illustrated in  FIG. 3   a,  the bottom of the holder device  7  is configured as a seating cone  26  with a locator pin  27  fitting into matching recesses of the load receiver  23  of the weighing device  22 . Also visible in  FIG. 3   a  is an overload spring  28 . Under an overload or other excessive downward force, the holder device  7  moves downward towards the seating cone  26  against the spring force of the overload spring  28  until the step  29  of the holder device  7  comes to rest on the rim of the opening in the horizontal plate  30  (see  FIG. 2 ). 
     FIG. 3   b  illustrates the clamping device  20  and the holder device  7  with a test tube  9  in a top view that shows how the clamping jaws  21  grip the test tube  9  from both sides through the window openings  25  (which are not visible in the top view of  FIG. 3   b ). 
     FIG. 4  illustrates the inventive dispensing apparatus  1  functioning as a part of an automated laboratory system  101  which in addition to the dispensing apparatus module  1  includes a robot (of which only the robot arm  102  is shown) holding a test tube  9 , storage racks  103 ,  104 ,  105 ,  106 , and a powder-delivery module  107  holding a powder container  108 . The storage racks  103 ,  104 ,  105 ,  106  can be configured to hold, e.g., empty and filled test tubes  9 , powder containers  108 , and container caps  110  (see  FIG. 5 ). The robot arm  102  moves in the x-, y-, and z-direction of a Cartesian coordinate system, while the gripper portion  109  with the gripper jaws  109   a  (shown in detail in  FIG. 5 ) is also capable of rotating about its vertical axis, for example to put a screw cap  110  on a container  9 . 
     FIGS. 5   a  and  5   b  illustrate the working end of the robot arm  102  of  FIG. 4  showing in particular the gripper portion  109  with the jaws  109   a  in the process of screwing a cap  110  onto a test tube  9 . 
     FIG. 6  illustrates a powder container  108  that is designed to be handled by the powder-dispensing module  107  which has a manipulating device  111  (see  FIG. 4 ) to handle powder containers  108  that are for example designed in accordance with  FIG. 1  (reproduced herein as  FIG. 6 ) of International PCT Application WO 02/090896, owned by the same assignee as the present application. The powder-dispensing operation can be summarized as follows:
     1. The robot arm  102  brings a powder container  108  to the powder-dispensing module  107 .   2. The manipulating device  111  of the powder-dispensing module  107  grips the powder container  108  and puts it in the proper position so that the screwdriver  112  can engage the Archimedean feed screw device  113  in the dispensing head  114  of the powder container  108 .   3. The manipulating device  111  moves the powder container  108  into a position above the test tube  9  (not visible in  FIG. 4 ) that is seated in the holder device  7  (not visible in  FIG. 4 ) of the inventive apparatus module  1 .   4. The manipulating device  111  turns the powder container  108  upside down.   5. The screwdriver  112  turns the feed screw device  113 , thereby dispensing powder into the test tube  9 .   
   The apparatus and method of the present invention have been described and illustrated in preferred configurations. However, guided by the teachings of the invention, persons of ordinary skill in the art will be able to realize further embodiments. In particular, the apparatus could be designed to have further capabilities and perform functions in addition to those that are expressly described and claimed. For example, the apparatus could also include the powder-dispensing device which, in the configuration described herein, is configured as a separate module.