Liquid dispensing apparatus with reduced clogging
US5458289A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 3, 1994 |
| Grant date | Oct 17, 1995 |
| Priority date | — |
| Expiry date | Feb 3, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB05B11/0039
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A pump dispenser connected to a container of liquid has a first piston reciprocatable in a first cylinder for pumping a quantity of liquid at each depression of the piston. A valve member received within a channel in the first piston is spring biassed into a position in which a dispensing outlet is normally closed and is movable to release liquid in response to excess liquid pressure in the first chamber. A cylindrical extension to the valve member defines a conduit communicating with liquid in the container and is separable from the valve member to open a liquid inlet port for recharging the first chamber. A second piston is movable in tandem with the first piston and cooperates with a second cylinder to provide suction on a return stroke of the pistons which is utilised to remove residual liquid from a dispensing channel delivering pumped liquid to a nozzle. Residual liquid collected in the second chamber is returned to the container during the next subsequent actuating stroke of the pistons. An actuator mounted on the first piston communicates lost motion to the second piston and provides valve action for applying suction to the dispensing channel. The dispenser is particularly …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.