Patent ID: 7361312
Filing Date: 2008-04-22
Classification: B01L

Abstract:
1. A disposable-type nozzle tip for use in a pipetting apparatus for aspirating and/or dispensing a liquid such as a reagent or a sample from and/or to a target container through an upper opening of the target container, the nozzle tip being adapted to be removably attached to a nozzle base of the pipetting apparatus, which comprises: a head portion having a plurality of ridges and an opening adapted to fit onto the nozzle base; a cylindrical portion extending downward from the head portion, the cylindrical portion having a lower end portion; a tip portion connected to the lower end portion of the cylindrical portion and having a liquid passage and a tip opening for aspirating and dispensing a liquid in a container, the tip portion having a diameter which is smaller than the diameter of the cylindrical portion; a step portion formed at an interface between the cylindrical portion and the tip portion so as to have a step-like form, wherein the step portion forms a bottom surface of the lower end portion of the cylindrical portion; and a plurality of fins, each fin including a ridge surface, said fins are provided on the bottom surface of the lower end portion of the cylindrical portion and extend downward along the peripheral surface of the tip portion up to a substantially intermediate portion thereof, the intermediate portion having a diameter less than a diameter of a bottom end of the tip portion, and the fins being spaced around the axis of the nozzle with substantially the same angular spacing therebetween, wherein an upper end of a ridge surface of each fin is level with a peripheral surface of the lower end portion of the cylindrical portion, and a lower end of the ridge surface of each fin is level with a peripheral surface of the intermediate portion of the tip portion, and wherein the plurality of fins function to guide the cylindrical portion into an opening of the container when the nozzle tip which is attached to the nozzle base is inserted into the container and to reinforce the tip portion, wherein the tip portion is tapered toward a tip thereof so that a peripheral surface of the tip portion is formed into a first inclined guide surface having a first angle which is defined by the central axis of the nozzle tip and the peripheral surface of the tip portion in the anti-clockwise direction and extending between the intermediate portion and the tip opening of the tip portion, and the ridges surfaces of the fins form a second inclined guide surface having a second angle which is defined by the central axis of the nozzle tip and one of the ridge surfaces of the fins in the anti-clockwise direction and which is larger than the first angle of the first inclined guide surface, wherein the first inclined guide surface has a sufficient length along the longitudinal direction of the nozzle tip with respect to a length of the second inclined guide surface so that these inclined guide surfaces can cooperatively exhibit the guiding function in a two stepwise manner when the nozzle tip is inserted into the target container through the upper opening in a misaligned posture, wherein the two stepwise guiding function includes a first guide function which corrects the misaligned posture to a certain degree with the sliding contact between the first inclined guide surface and the edge of the upper opening of the target container and a second guide function which corrects the misaligned posture to a greater degree with the sliding contact between the second inclined guide surface and the edge of the upper opening of the target container, in which the first guide function and the second guide function are performed in a continuous manner according to the insertion of the nozzle tip into the target container; and wherein each fin has a substantially triangular plate-like shape having a thickness thinner than the diameter of the tip portion at the intermediate portion thereof and the fins are structured on the tip portion so that spaces are formed between the adjacent fins through which the outer periphery of the tip portion is exposed, and wherein at least the tip portion is composed of a resin material of the type through which changes of a liquid surface level in the liquid passage can be observed through the exposed outer periphery of the tip portion when aspirating and dispensing the liquid through the liquid passage.