| 摘要 |
The body is a straight tube, of circular cross section, having a knurled ring at the front end for the hypodermic needle holder. Inside the tube is a piston with sealing rings and having a conical projection at the rear. This projection forms a boss for the piston rod which passes through an aperture in the other closed end of the tube. The aperture has an internal cone shape and, after drawing the sample, the piston is pulled back so that the boss wedges in the aperture. Projections prevent rotation, allowing the rod to be removed and the tube sealed. |
