Conveyors: power-driven – Conveyor section – Load propelled as the reactive means in a linear motor or...
Reexamination Certificate
2001-11-14
2003-06-03
Ellis, Christopher P. (Department: 3651)
Conveyors: power-driven
Conveyor section
Load propelled as the reactive means in a linear motor or...
Reexamination Certificate
active
06571934
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for automatically processing a patient's biological fluids such as urine, blood serum, plasma, cerebrospinal fluid and the like. In particular, the present invention provides a magnetic drive system for moving liquid samples in containers held in a rack into and out of a clinical analyzer.
BACKGROUND OF THE INVENTION
Various types of tests related to patient diagnosis and therapy can be performed by analysis assays of a sample of a patient's infections, bodily fluids or abscesses for an analyte of interest. Such patient samples are typically liquids placed in sample vials, are extracted from the vials, combined with various reagents in special reaction vessels or tubes, incubated, and analyzed to aid in treatment of the patient. In a typical clinical chemical analysis, one or two assay reagents are added at separate times to a liquid sample having a known concentration, the sample-reagent combination is mixed and incubated. Interrogating measurements, turbidimetric or fluorometric or absorption readings or the like, are made to ascertain end-point or rate values from which an amount of analyte may be determined, using well-known calibration techniques.
Although various known clinical analyzers for chemical, immunochemical and biological testing of samples are available, analytical clinical technology is challenged by increasing needs for improved levels of analysis. Automated clinical analyzers improve operating efficiency by providing results more rapidly while minimizing operator or technician error. However, due to increasing demands on clinical laboratories regarding assay throughput, new assays for additional analytes, accuracy of analytical results, and low reagent consumption, there continues to be a need for improvements in the overall performance of automated clinical analyzers. In particular, the efficiency of patient sample handling continually needs to be increased, regardless of the assay to be performed.
An important contributor to maintaining a high efficiency in throughput of patient samples is the ability to quickly and securely introduce a plurality of samples to the sample testing portion of an analyzer. Patient samples are typically held in a container such as a sample cup, a primary tube, or any other suitable container and may be open at its top or closed with a stopper or lid or the like at its top. To increase handling efficiency, the containers may then be placed into a sample rack adapted to support multiple sample containers generally in an upright orientation.
The sample rack is usually placed in an input portion of the analyzer and then moved to a location where a portion of the liquid patient sample is extracted, usually by aspiration using a hollow, needle like probe from the sample container for testing in the analyzer. Afterwards, the sample rack may be moved to temporary storage area or to an output portion of the analyzer where the user can conveniently remove the sample rack from the analyzer. It is known in the art to employ magnetic conveyor mechanisms transporting a source of a magnetic field to move sample racks having a ferromagnetic element and containing open or closed sample containers along input and output lanes. Hereinafter the term ferromagnetic is intended to mean a substance having a sufficiently high magnetic permeability to be positionally affected by a changing magnetic field. Likewise, the term magnetic is intended to mean a substance that is independently capable of generating a magnetic field.
When handling sample racks supporting open sample containers, magnetic conveyor mechanisms must be designed to gradually increase the strength of the magnetic field as the magnetic conveyor mechanism approaches a sample rack, thereby providing smooth and continuous handling of a sample rack containing open sample tubes so that the possibility of spillage is minimized. Such systems require precautions to prevent abrupt movements of a sample rack so that the possibility of spillage of liquid sample from an open container is minimized and/or so that the possibility of damage, for example from re-suspension of red blood cells, to liquid sample in a closed container is minimized. U.S. Pat. No. 5,720,377 addresses this need by providing a magnetic plate positioned at the bottom surface of a sample rack and a number of belt driven magnet assemblies moving below the surface of a tray. The magnetic field generated by the magnet assemblies attract the plates disposed in the bottom surface of the sample rack and engages the plate with sufficient force such that the sample rack moves along the tray in concert with the magnet assembly as the belts move. A portion of the plate is disposed at an angle with respect to the surface of the magnet assembly such that the magnetic force provided by the magnet assembly gradually builds as the belt moves, thereby to lower the backward acceleration of the rack as the magnet assembly first approaches the sample rack. This system, however, is not operable in two opposing directions along a single lane in the tray because the angular portion is unidirectional. Such a system has disadvantages whenever an analyzer is desired to be capable of moving sample racks in two directions along a single lane, for instance when an analyzer requires only a single sample rack input/output lane to achieve needed capacity. Such disadvantages also must be overcome when modular analyzers are linked together to increase capacity and it is necessary to convert separate input and output lanes into a pair of input or output lanes.
It is therefore desirable to provide a magnetic sample transport system and sample container rack which is capable of smoothly transitioning a sample rack containing open or closed sample containers along an operating surface from a moving state to a stationary position. It is further desirable that such a magnetic sample transport system be capable of bi-directional movement of sample racks along either an input or output lane without the necessity for additional mechanisms which increase cost and design complexity and reduce reliability. It is even further desirable that such a magnetic sample transport system have a solid operating surface so that in the event of sample liquid spillage or container breakage, liquids contained in the sample containers is prevented from flowing into and harming internal portions of the analyzer and so that the operating surface may be easily cleaned. It is finally desirable that the magnetic sample transport system have no operating mechanisms above the operating surface, other than the moving sample rack, in order to eliminate moving danger points to an operator.
U.S. Pat. No. 6,206,176 discloses a magnetic drive system for moving a substrate transfer shuttle along a linear path between chambers in a semiconductor fabrication apparatus. A rack with rack magnets is secured to the shuttle, and a rotatable pinion with pinion magnets is positioned adjacent the rack so that the pinion magnets can magnetically engage the rack magnets. Rotation of the pinion causes the shuttle to move along the linear path. The magnets may be oriented with a helix angle between their primary axis and the axis of rotation of the pinion. One rack and one pinion are located on each side of the shuttle. A set of lower guide rollers supports the shuttle, and a set of upper guide rollers prevents the shuttle from lifting off the lower guide rollers.
U.S. Pat. No. 5,906,262 provides a positioning control system to control stoppage of a conveyed article with a magnetic conveyor system element on the receiving side when a conveyed article is passed between magnetic conveyor device elements in a noncontacting magnetic conveyor system. The system comprises two independently operating magnetic conveyor system elements and two drive shafts, each of which has helical magnetic poles at its surface. The carrier is equipped with magnetic poles of equal pitch to the pitch of the helical magnetic poles. When the rotary shaft
Dunfee William D.
Gillund Daniel E.
Thompson David R.
Vijay Tumkur R.
Dade Behring Inc.
Ellis Christopher P.
Jordan Leland K.
Ridley Richard
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