Method and apparatus for dispensing liquid
US4519526A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 25, 1982 |
| Grant date | May 28, 1985 |
| Priority date | — |
| Expiry date | Mar 25, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F11/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An anti-drip system for a dispenser in the form of a deformable conduit adapted to dispense a liquid, such as a photoresist, from a dispensing tip located at one end of the conduit includes a rigid housing which surrounds an intermediate portion of the conduit. The housing is closed except for a port which permits pressurized air to be supplied to and exhausted from the housing. At the commencement of a dispensing operation, the liquid is transported through the conduit as the housing is simultaneously pressurized, thereby crimping the intermediate portion of the conduit. At the conclusion of the dispensing operation, air pressure in the housing is simultaneously reduced, thereby allowing the conduit to expand and assume its natural substantially uncrimped shape. Expansion of the conduit creates a vacuum sufficient to suck back liquid which is being dispensed from the conduit. A pair of anti-drip systems may be utilized in combination with a pair of valves to actually meter liquid which is being dispensed through a deformable conduit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.