| 摘要 |
A dispenser for flowable materials having a dispensing head with a chamber having inlet and discharge openings of a predetermined volume, a closure to open and close the inlet, a body which can be positioned in the chamber, for occupying a portion of its volume, a supply of flowable material to the inlet, and, the body being moveable from within the chamber so that at least a portion of the body is withdrawn from the chamber to increase the effective volume of the chamber and cause material in the discharge opening to be sucked back into the chamber. |
