Positive displacement liquid drawing and dispensing apparatus
US5770160A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1997 |
| Grant date | Jun 23, 1998 |
| Priority date | — |
| Expiry date | Jul 25, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/2575
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A positive displacement liquid drawing and dispensing apparatus (21) having a tubular member (22) with an axially extending lumen (24) and a plunger (31) mounted for axial displacement in the lumen (24). The plunger (31) has a first seal (33) positioned proximate an end (34) of the plunger and a second seal (37) axially spaced from the first seal (33). The first and second seal each slidably and sealingly engage an interior surface (23) defining the lumen (24) as the plunger (31) is displaced in the lumen. The plunger further includes a recess (38) intermediate the first and second seals for receipt of trapped gas (40,41) which can be drawn in through an intake end (27) of the lumen during drawing of the liquid (36) into the tubular member (22). The plunger is formed for positioning of the first seal (33) beyond the intake opening (27) so that air will automatically be isolated between the first and second seals (33,37) as the plunger is withdrawn into a lumen. A substantially gas-free draw of liquid will result between the first seal (33) and the intake opening (27). A method of drawing the liquid in the apparatus which includes automatically isolating an uppermost portion of the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.