US3874598A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Irrigation tube
Assignee: Dow Chemical Co
•
Filing: 1973-12-17
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Granted: 1975-04-01
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Expires: 1993-12-17
Abstract
Abstract Plastic low pressure irrigation tube is prepared by forming a two-passageway tube having a supply and discharge passage. The wall separating the two passages is perforated to permit liquid to flow from the supply to the discharge passage. The external wall forming the discharge passage is perforated at locations remote from perforations connecting the supply and discharge passages to provide relatively even distribution of water therefrom with variations in the pressure head on the inner tube.
Inventors
- 👤 Carl B Havens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 04:27
CPC Classifications
A; A01; A01G; A01G25/00; A01G25/06
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
134 words
An irrigation tubing comprising a first or inner conduit, the inner conduit having generally constant wall thickness, a plurality of perforations disposed in the wall of the inner conduit providing a plurality of passages through the wall thereof, an outer adjacent conduit enclosing the inner conduit, the adjacent conduit having a plurality of openings passing through the wall thereof, the total cross-sectional area of the openings per unit length of the conduits being greater in the outer conduit than in the inner conduits, the inner and adjacent conduits being of flexible plastic material readily deformable to a flat ribbonlike shape, with the further limitation that the outer adjacent tube has spaced apart annular regions of reduced diameter and the inner tube and the outer tube define a plurality of generally annular elongated compartments therebetween.
Claim 2
Dependent Claim
134 words
An irrigation tubing comprising a first or inner conduit, the inner conduit having generally constant wall thickness, a plurality of perforations disposed in the wall of the inner conduit providing a plurality of passages through the wall thereof, an outer adjacent conduit enclosing the inner conduit, the adjacent conduit having a plurality of openings passing through the wall thereof, the total cross-sectional area of the openings per unit length of the conduits being greater in the outer conduit than in the inner conduits, the inner and adjacent conduits being of flexible plastic material readily deformable to a flat ribbonlike shape, with the further limitation that the outer adjacent tube has spaced apart annular regions of reduced diameter and the inner tube and the outer tube define a plurality of generally annular elongated compartments therebetween.
Claim 3
Dependent Claim
20 words
The tubing of claim 1 wherein the plastic tubing has a wall thickness of from about 2 to 20 mils.
Claim 4
Dependent Claim
22 words
The tubing of claim 2 wherein the inner and adjacent tubes have a wall thickness of from about 3 to 12 mils.
Claim 5
Dependent Claim
34 words
The tubing of claim 1 wherein the ratio of the area of the openings in the adjacent tube to the area of the openings in the inner tube is from about 1.1 to 50.
Claim 6
Dependent Claim
14 words
The tubing of claim 1 wherein the inner tube is an extruded seamless tube.
Claim 7
Dependent Claim
19 words
The tubing of claim 1 wherein the inner and outer adjacent tubes each have a longitudinal axial lap seal.
Claim 8
Dependent Claim
37 words
The tubing of claim 1 wherein the inside diameter of the outer adjacent tube and the outside diameter of the inner tube differ by about 0.1 to about 10 percent of the diameter of the inner tube.
Claim 9
Dependent Claim
37 words
The tubing of claim 7 wherein the inside diameter of the outer adjacent tube and the outside diameter of the inner tube differ by about 0.2 to about 4 percent of the diameter of the inner tube.
References Cited (Backward Citations)
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Cited
US2851306A
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US3080124A
Cited
US3467142A
Cited
US3672571A
Cited
US3567134A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |