| 摘要 |
The invention relates to a device used for filling a liquid chamber of a liquid dispensing apparatus by means of a pressurised gas fed from a source of pressurised gas into the liquid chamber. This device comprises two opposite active surfaces: a first surface permanently exposed to the gas medium at a predetermined pressure, and a second and bigger surface which can communicate through a valve means either with the source of pressurised gas or with the atmosphere to move the piston assembly between two end positions defined by two spaced apart sealing seats of the housing and by the two spaced apart sealing surfaces of the piston assembly. A housing chamber associated with the first sealing seat is connected to the liquid chamber, so that for any position of the piston assembly between its end positions, the liquid chamber remains in communication with the source of liquid through a channel formed between the sealing seats. The piston assembly comprises a dosage piston which is disposed in a dosage chamber filled with a fluid and to which a bottleneck device is associated, so that at least during the move of the piston assembly, when the second active surface is exposed to a pressure, the fluid flows, through the bottleneck of the dosage chamber, from one chamber section, situated on one side of the dosage piston, to the other chamber section, situated on the other side of the piston. |
