Chemistry: molecular biology and microbiology – Apparatus – Including measuring or testing
Reexamination Certificate
2000-11-16
2003-02-25
Redding, David A. (Department: 1744)
Chemistry: molecular biology and microbiology
Apparatus
Including measuring or testing
C435S286400, C435S287400, C435S288700, C422S065000
Reexamination Certificate
active
06524845
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns an apparatus for the determination of microorganisms in liquid test specimens, including a specimen providing station with a transport apparatus for the continuous presentation of cuvettes containing specimens to be investigated, a dosing station with a pipetting apparatus for removing specimens from the cuvettes and for filling the specimens into measuring chambers formed in a measuring chamber plate in matrix arrangement, and a measuring station with a measuring apparatus for optically measuring the specimens in the measuring chambers.
BACKGROUND OF THE INVENTION
In order to be able to detect, for example, bacteria in liquid test specimens with an apparatus of the previously mentioned kind, one proceeds as follows. The measuring chambers of the measuring chamber plate, a so-called microtitration plate, are filled with a culturing solution and/or detection chemicals for certain bacteria. A specimen is distributed to a number of chambers. With the help of the measuring device, it is tested whether the absorption behavior of the solution in the measuring chambers changes, especially whether a color reaction appears because of the detection chemicals. If this is not the case, the measuring chamber plate is placed in an oven to produce a multiplication of the bacteria in the individual measuring chambers. The above-mentioned steps must be repeated many times during a time period of from six to eight hours. This means that the measuring chamber plate has to be taken out of the oven by means of a grasping system and moved to the dosing unit, the measuring unit, and finally back into the oven. This is time consuming and requires not only a high mechanical expense but also much space for the storage of the measuring chamber plates. If an error appears in the mechanical handling which is not immediately noted, the process because of its long duration often cannot be started again until the next work day.
The invention has as its object, to simplify the manipulation of the measuring chamber plates and thereby to avoid sources of error, as well as to reduce the space requirement of the apparatus.
SUMMARY OF THE INVENTION
These objects are solved by an apparatus of the previously mentioned kind and in accordance with the invention by an endless conveyor which is formed to serially receive the measuring chamber plates and to transport the same through the dosing station, the measuring station and through a temperature controllable waiting zone.
In the solution of the invention, the measuring chamber plates remain connected with the endless conveyor during the entire duration of the investigation. The grasping apparatus required by the state of the art for the manipulation of the measuring chamber plates can be eliminated. Thus, the technical expense is lowered and also so is the space requirement for the apparatus of the invention. Since the previously required manipulation procedure offered an abundance of error sources, the apparatus of the invention in operation is also essentially more functionally reliable than customary apparatuses of this kind.
Preferably, the endless conveyor has a plurality of carrier frames each having at least one receiving compartment for a measuring chamber plate. Therefore, the measuring chamber plates can in a simple way be connected with the endless conveyor, insofar as each is simply inserted or pushed into a receiving compartment.
The endless conveyor preferably has an endless conveying member, for example, a belt or chain, which is guided over rolls and to which the carrier frames are fastened. To save space, or with the same space allotment to increase the storage capacity for the measuring chamber plates, the conveyor member can run in at least two vertically superimposed planes. This can be achieved in a simple way in that at two horizontally spaced locations at least two belt rolls are arranged axially over one another, and that at least a further direction changing roll is provided for the conveyor member which has a location outside of a connecting line between the first mentioned belt roll locations. In this way, the carrier frames fastened to the conveyor member can change from one plane to the other without obstructing one another.
The use of so-called microtitration plates in which the measuring chambers each have a very small volume requires an exact positioning of the measuring chamber plates in the optical measuring apparatus. To achieve this, it is advantageous if guide means are provided at the measuring station for guiding the carrier frames relative to the measuring apparatus. Thereby the measuring chamber plates can be positioned exactly with respect to the measuring optic system despite the flexibility of the conveyor member.
In a preferred embodiment the guide means include guide rolls arranged on both sides of the transport path of the carrier frames and which come into engagement with the side edges of the carrier frames running parallel to the transport direction. To on one hand make possible a jolt-free introduction of the carrier frames between the guide rolls and on the other hand to assure an exact positioning, it is advantageous if the guide roll intended for engagement with one of the side faces is biased in the direction toward to the oppositely lying guide roll. Thereby a play-free engagement of the guide rolls onto the side surfaces of the carrier frame is assured.
In order to avoid not only sideways deflection but also movement of the measuring chamber plates in the vertical direction inside of the measuring station, it is proposed that guide grooves are formed in the side surfaces of the carrier frames running parallel to the transport direction, which grooves receive corresponding portions of the guide rolls. The centering of the carrier frames at the measuring station can, in this case, be further improved if the guide grooves and/or the guide rolls in their edge areas have a V-profile.
The receiving compartment of the carrier frame is preferably formed as a sliding guide with an opening lying at the side of the carrier frame remote from the conveyor member. Because of this, the measuring chamber plates can be pushed into the associated receiving compartments by a simple pushing mechanism at the dosing station and can also be likewise easily removed.
Since the measuring chamber plates remain in the carrier frames during the entire investigation procedure and are also measured while in the carrier frames, it is advantageous if the carrier frames either have entirely no bottoms or if the bottom of the receiving compartment at least in the region of the measuring chambers of a measuring chamber plate inserted into the receiving compartment is transparent. This can occur either in that a transparent plate is so printed that measuring areas only remain free at the desired spots or in that the bottom of the receiving compartment at the spots corresponding to the measuring chambers of a measuring chamber plate inserted into the measuring compartment has passthrough openings.
To simplify the automatic delivery of the measuring chamber plates for the inoculation, it is advantageous if at the dosing station, at least one magazine pocket is provided for the storage of measuring chamber plates stacked upon one another and if a delivery device is also provided for delivering the uppermost or lowermost measuring chamber plate of the stack from the magazine pocket to a receiving compartment of a carrier frame moving past the dosing station. Also, in the case of this solution, no complicated grasping system is needed. It is sufficient to have a simple pusher for removing the measuring chamber plate from the magazine. If the magazine pocket is located below the delivery surface for the insertion of a measuring chamber plate into a receiving compartment, it is advantageous if, in the magazine pocket, an upwardly biased bottom plate is arranged so that the entire measuring chamber plate stack is always pushed against an upper stop.
The delivery mechanism for delivery of the measuring chambe
Deuter Klaus
Markart Ernst
Siris Genrich
Voigt Michael
LRE Technology Partner GmbH
McCormick Paulding & Huber LLP
Redding David A.
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