Patent GB-1229971-A (GB)
IPC: G01N35/04
Filed: 1968-04-29
Abstract: 1,229,971. Photo-electric analysis. CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE and CENTRE NATIONAL DE TRANSFUSION SANGUINE. April 29, 1968 [May 12, 1967; March 22, 1968], No.20192/68. Heading G1A. [Also in Divisions B1, B8 and G2] In the analysis of liquid samples, for example in blood group determinations on blood samples which have been transferred from tubes 6 to transparent-bottomed dark walled cups 27, Fig.12a, arranged in sections 21 of support disc 20, Fig.2, mixtures of liquid sample and reagent in the cups are subjected to at least two successive agitations on turn-table 86 the first agitation being at a higher speed than a critical speed at which any agglutinated or precipitated material in the sample cups is dispersed in the liquid medium, and the second agitation being at a lower speed than the critical speed when such material is collected near the centre of the bottom of the cups, then a photo-metric measurement is made on the contents of the cups by means 115-116. Each tube 6 is of plastics material moulded with an integral vertical tongue (15a), (15b), Fig.3 (not shown) to which an identifying card 9 to be read by means 148 is attached. The tube and tongue fit between adjoining pillars (13) on turn-table 11, Fig.6 (not shown). Discs 20 carrying sample cups 22 are vertically stacked in drum 30, Fig.14 (not shown) which releases them in turn on to centrifuge turn-table 55, where agglutinated material is centrifuged down prior to transfer of the disc by endless chains (72), Figs. 18, 19 (not shown) to agitating turn-table 86. In the embodiment shown, in taking samples from tubes 6 on turn-table 11, probes 41, 42 mounted on pivoted arm 38 are lowered into a tube 6 and samples of settled blood corpuscles and of plasma are sucked out by probes 41, 42 respectively, which in operation reach to different depths in the tubes, Fig.16 (not shown). Arm 38 then moves over disc 20 and discharges the blood corpuscle and plasma samples into radial grooves 25, 26 in a sector 21 of disc 20. Simultaneously the twelve-probe assembly 43-44 mounted on vertically movable sheet 33 is lowered so that the probes dip into a set of sample cups 27 in the preceding sector 21 to discharge into the sample cups liquid sucked from the grooves 25, 26 of that sector in the previous movement. In an alternative embodiment, Figs.28 and 29 (not shown), sample tubes 6 with associated auxiliary tubes (6a) carried in loaders (200) pass beneath probe (203) which transfers part of each sample together with some saline to the corresponding tube 6a. Tubes 6, 6a then pass to probes (206), (207)connected to peristaltic pump (208), which removes samples from each pair of tubes 6, 6a and discharges them together with reagent from containers 212, Fig.29 (not shown) into cups (22) on a disc 20. Figs. 30 to 33 (not shown) show the optical system employed to measure the opacity of the agglutinated matter and/or the turbidity of the surrounding medium. Screens are placed between the light source (117) and each lens and photo-cell or photo-cell pair assembly with perforations arranged in the screens to allow passage of light only through the appropriate part of the bottom of the cup. Photo-metric measurements are made through the centre of the transparent bottom of the cups and/or through the periphery of the bottom of the cups. The results may be automatically compared with threshold values corresponding to agglutination or non- agglutination of the reaction mixture, the print-out of the results together with the corresponding automatically pre-checked patient identification information being arranged to distinguish between clearly classifiable results and borderline results needing particular consideration.