Precompression metering pump with improved priming
US4930999A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 1989 |
| Grant date | Jun 5, 1990 |
| Priority date | — |
| Expiry date | Jun 2, 2009 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB05B11/1018
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A precompression metering pump of the prior art which is otherwise particularly advantageous, is nevertheless difficult to prime because of the high degree of compressibility of the air it initially contains in its pump chamber. The present invention improves this aspect of metering pump operations. It consists in providing additional resilient means (20) and at least one cylindrical part (10) level with the conventional outlet non-return valve of the pump and constituting a second outlet non-return valve. In a particular embodiment, the resilient means and the cylindrical part are received one above the other in the outlet channel (33) of the pump actuator rod (31). To do this, they bear respectively against a choking step (32) in the form of a lug and a shoulder (34) presented by said channel. In normal operation, the differential piston (4) of the pump moves out of the way so that operation takes place as in a prior art precompression metering pump. However, when priming, by pushing the actuator rod (31) fully home, as is made possible by the invention, the part (10) is moved away from the choking step (32). This improvement thus enables the air which was initially contained in …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.