GB936861A - Improvements in or relating to apparatus for automatically performing laboratory operations - Google Patents

Abstract

<PICT:0936861/III/1> <PICT:0936861/III/2> An apparatus for automatically performing laboratory operations comprises a work-table with superposed horizontal working planes on which receptacles may be placed, a three-dimensionally displaceable device supported by said work-table and carrying a set of pipettes in order to bring at least a main pipette over a receptacle on one of said planes to remove or add liquid thereto, a motor-driven pump connected to said pipettes for controlling the suction or discharge of fluid therethrough, a liquid level detector moving along said main pipette under the action of an electric motor, and a grip unit vertically movable on said movable device for transferring said receptacles, and means for automatically controlling said displaceable device, said motor-driven pump, said liquid level detector and said grip unit according to a desired cycle of operations. In Fig. 1 the pipette p is supported in a housing to form a pipette unit B. The pump MP (see Group XXVI) is energized by two constant speed reversible motors linked by epicyclic transmission (see Group XXIV) and controlled by an electrical circuit Q (Fig. 13, not shown) in dependance on signals from the liquid level detector which is a photoelectric device Cm which can be brought by means of motor M3 into register with a liquid miniscus in the pipette. MP can alternatively be a variable speed motor. An upper miniscus level indicated by Cf provides further control signals. The location of the device Cm is shown on a direct indicator I2 and also electrically by means of a potentiometer device P2 generating voltage V2 which is indicated and recorded by an assembly 19. The record may be in the form <PICT:0936861/III/3> of a continuous graph or a cyphered indication given by means of an electrical typewriter. As a further alternative the pipettes or voltage indicating apparatus may be photographed. Motor M3 is controlled by a voltage-comparing device L (Fig. 12, not shown) connected to an adjustable voltage generator SV1. (Figs. 14 and 15, not shown). The control device Q also controls motor M6 which raises and lowers the pipette unit. By means of these controls the apparatus may be automatically caused to withdraw a predetermined quantity of liquid from a vessel discharge liquid into a vessel, repeat these steps to effect rinsing and thereafter suck air to effect drying, or to indicate a volume of liquid discharged, e.g. during a titration having a colour change end point detected by a colorimeter producing a signal applied to control device Q. A console or control assembly Pu is provided. Another form of control is shown at Cg which is a dropping tube cell measuring a number of drops and thereafter applying a signal to Q to cause the cessation of discharge. In Fig. 5 the pipette unit B is shown mounted in a carriage F which is in turn mounted and equipped for front to rear movement in carriage T. The latter can be moved transversely on fixed rails 87, 88. A gripping unit G movable on unit B is provided for grasping and releasing vessels. Figs. 6-11, not shown, illustrate how carriages F and T and unit G each are equipped with a motor and appropriate gearing. Each has also a controlling device (Fig. 18, not shown) whereby the carriage or unit can be moved in a stepwise manner, and thus effect the transfer, e.g. of a vessel 78 from a given crossing point of a grid in a plane P1 to another crossing <PICT:0936861/III/4> point of the grid in the same or another plane. The planes P1 and P2 correspond to two levels of a work bench shown in plan in Fig. 25, which comprises a number of associated pieces of apparatus each of which is so designed that a part thereof on which a receptacle is to be placed or at which an operation to be formed is located at a crossing point of one of said grids. Pieces of apparatus specified are an oven (230a), a water bath (234), a centrifuge (223), a colorimeter (not visible), a shaking agitator (226), racks (e.g. 204) (also adapted to be moved by the gripping unit) for vessels such as test tubes or rectangular storage vessels, movable washing tanks (241, 241a), and a washing device (not shown) below the surface of bench to which vessels can be admitted through aperture 227 and recovered through aperture 228. In addition a scintillator or spinthariscope with a scintillator counter, an evaporator, a weighing device, a pH meter and a Geiger counter are mentioned. If desired the series of pipettes identical with pipette p and shown in Fig. 23 may be employed: this permits the simultaneous performance of a number of similar operations. The pipettes are housed in a unit B1 which can be secured to pipette unit B and moved in conjunction therewith.