Porous irrigation pipe and method
US4616055A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 13, 1985 |
| Grant date | Oct 7, 1986 |
| Priority date | — |
| Expiry date | May 13, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S138/07
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A mixture of virgin crumb rubber sized to between 30 mesh and 100 mesh containing less than 5%+100 fines and thermoplastic binder, such as carbon black filled polyethylene containing a coating promoter, such as a citrate salt and lubricant, such as a calcium stearate, is mixed in a vented Banburg mixer heated to at least 350.degree. F. to remove volatiles through vent before extrusion. The mixture is formed into sheet in the nip of a two roll assembly and cooled in air before diced into pellets by a dicer. The pellets are formed into porous pipe by extrusion in a pipe extruder having the feeding, transition and metering zones separately heated to temperatures from 320.degree. F. to 400.degree. F. (T.sub.1, T.sub.2, T.sub.3). The die has a separate jacket receiving heat exchange fluid for heating the die to a temperature from 290.degree. F. to 380.degree. F. to form a porous pipe having more uniformly spaced and sized pores and a smoother inner wall surface. The linearity factor, tensile strength and elongation are also improved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.