| 摘要 |
<p>In a liquid dispenser, a piston rod (31) is mounted for lost motion on a piston head (33) mounted for reciprocation in a cylinder (32) so that when the piston rod is advanced by a full stroke (S1) in a forward direction (D) from a fully retracted position, only the piston rod moves for an initial stroke portion (S2), whereafter the piston head is also advanced with the piston rod for a final stroke portion (S3) which is equivalent to a difference between the full stroke and the initial stroke portion so that a liquid said cylinder is expelled from the dispenser in a quantity corresponding the final stroke portion. When the piston rod is withdrawn in the return direction (U), only the piston rod is moved during an initial stroke portion so as to cause residual liquid in a passageway (39) from the cylinder to the exhaust port to be sucked back in to the cylinder through an open check valve (36). <IMAGE></p> |
