| 摘要 |
<p>The pipette has a body onto which a lower tube is screwed; and the lower tube has a bore with an exact dia., contg. a piston located on the bottom end of a control rod. A conical tip is fitted onto the bottom end of the lower tube. On the top end of the control rod is a pad; and a push-button drives the pad downwards to move the rod and therefore the piston. The downwards travel of the pad is restricted by a limit stop; and a helical coil spring pushes the pad upwards to its initial position when the pressure of a human finger on the push-button is removed. The piston thus moves along a path with a specific length, so a specific vol. of liq. is driven out of the pipette tip. The pipette tips do not require calibration, and are inexpensive.</p> |
