Process for making drip irrigation lines
US4702787A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 10, 1983 |
| Grant date | Oct 27, 1987 |
| Priority date | — |
| Expiry date | Jun 10, 2003 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T156/1095
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method for making drip irrigation lines comprises feeding an elongated sheet of flexible polyethylene film to an injection molding machine for injection molding a series of drippers across a face of the film. A moldable thermoplastic material is injected into multiple die cavities, forming separate drippers each simultaneously heat-bonded to the film. Each dripper has a molded labyrinthine flow-restricting passage extending along it. The mold is opened, the film is advanced, and further series of drippers are injection molded across the face of the film. The previously molded set of drippers are closed off by heat sealing a separate strip of flexible film to a face of each molded dripper to form sealed internal pressure-reducing labyrinthine passages in the drippers. An inlet opens into one end of the sealed internal passage and an outlet opens from the opposite end through the film. The outlet is formed and reinforced during the molding process. A second layer of film is overlayed on the sealed drippers and on the film onto which the drippers are heat-bonded. The second film is bonded to the other film along parallel seams between the drippers, and the film is then cut along the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.