| 摘要 |
<p>A tube for the sepn. by centrifuging of the heavier components from the lighter components of a liq. e.g. blood, and preventing subsequent mixing of the components, contains a cylindrical body, the density of which is between that of the components, and the external dia. of which is equal to the internal dia. of the tube. The tube is made of a synthetic material. During the centrifuging, the cylindrical body slides along the tube. The lighter component flows past it in the space formed between the body and the tube by the slight expansion of the tube, so that the body is always at the interface between the heavy and light phases. A suction piston may be attached to the cylindrical body and the tube may have a ferrule for an injection needle so that a sample can be drawn into the tube. The suction piston shaft is removed before centrifuging. Problems associated with excessive friction between glass tubes and plugs of elastomeric material, diffusion of mixt. through filter discs, and complicated methods of introducing the sample are avoided. The appts. is simple to make, e.g. by injection moulding. Mixing or diffusion of dissolved components is prevented, even during transport or prolonged storage. Filling is simpler, partic. when the appts. is used for sampling blood.</p> |
