| 摘要 |
Medical specimens suspected of containing harmful microorganisms are diluted in saline solution and the dilution so formed is vacuum loaded into a cuvette or card containing viewing walls having dried selective culture media therein. The dilution rehydrates the culture media, each of which is selective in the sense that its optical characteristics will change when the organism to which it is specific metabolizes within it. A plurality of the cards are loaded into a tray, and the tray is placed on a rotatable carrousel of a card holder unit along with other trays. The carrousel is indexed at periodic intervals, and each time that it is indexed a different tray moves to a reading position facing a card reader unit. The carrousel has a center stack from which heated air is discharged such that it passes along both major surface areas of the cards in the tray, thus maintaining the cards at a temperature suitable for incubating microorganisms in them. The reader unit includes a reader head which moves vertically along that tray which is in the reading position, and this head has extractor and locator slides which move horizontally. The extractor slide engages each card and withdraws it individually from the tray, while the locator slide, which is spring loaded with respect to the extractor slide, bears against the card as it is withdrawn so as to maintain it in the proper orientation with respect to arrays of light emitters and corresponding detectors on the reader head. The emitters and detectors are arranged in pairs, with the detector of each pair being illuminated by the emitter, unless otherwise obscured. The card as it is withdrawn by the extractor slide moves between the pairs of emitters and detectors, and as it does some of the pairs register with identification segments on the card while other pairs register with the viewing wells. The former "read" identification numbers marked on the card with opaque ink, while the latter determine the light transmitting characteristics of the wells, this being achieved by projecting the light from the emitters through the wells and measuring the intensity of the light falling upon the detectors. A change in the light transmitting characteristics of a well indicates the presence of the specific microorganism in the well. That change provides a unique signature for the specific microorganism. |
