The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 25, 1990
Filed:
May. 03, 1989
William S Mitchell, McKenzie, TN (US);
Prescision Porous Pipe, Inc., McKenzie, TN (US);
Abstract
This invention relates to the manufacture of flexible porous irrigation pipe having an essentially uniform porosity throughout its length which is produced by extruding an essentially moisture-free non-homogeneous, mixture of pre-vulcanized elastomeric particles such as reclaimed crumb rubber from vehicle tire treads in major amount and a thermoplastic polymer binder such as low-density polyethylene in minor amount. The mixture is intimately mixed and extruded from an unvented extruder through an annular extruder die at a precisely-controlled temperature and then through a lengthy cooling liquid bath, the rate of pull-off through the extruder die and liquid bath being maintained constant. The leak rate of the fluid delivered from the porous pipe is substantially uniform over a lengthy prescribed dimension exhibiting a delivery variation of less than about 5 percent per unit of length.