Fluid pump dispenser having product retraction feature
US6334549B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 2001 |
| Grant date | Jan 1, 2002 |
| Priority date | — |
| Expiry date | Mar 16, 2021 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB05B11/1047
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A fluid pump dispenser of the loss motion piston type provides for maintaining the discharge open a slight interval at the commencement of each plunger upstroke while the pump chamber expands to retract product from the discharge passage into the chamber to thereby avoid the formation of product droplets at the exit end of the discharge. Such is effected in accordance with one embodiment by reducing the friction force acting between the piston and the pump cylinder relative to the friction force acting between the piston and the stem. In another embodiment an inlet valve assembly has a portion lying in the path of the piston which portion is connected by spring legs to a valve portion such that the restoring force of the spring legs shifts the piston together with the stem at the commencement of the plunger upstroke which maintains the discharge passage in open communication with the chamber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.