US3798836A
Expired / Lapsed
US
⏱️ 0.0 years remaining
A hydroponic bed for growing plants
Assignee: Dow Chemical Co
•
Filing: 1972-12-04
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Granted: 1974-03-26
•
Expires: 1992-12-04
Abstract
Abstract A novel hydroponic bed is disclosed comprising an aqueous nutrient solution and floating thereon a composite foam plant growth medium composed of a water insoluble open celled foamed polyurethane matrix having dispersed therein expanded cellular thermoplastic particles and a small amount of a water swellable, cross-linked hydrophilic polymer.
Inventors
- 👤 L Rubens
- 👤 D Clarke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:13
CPC Classifications
A; A01; A01G; A01G24/00; A01G24/30; A01G24/35; A01G24/40; A01G24/48; Y; Y10; Y10S; Y10S260/00; Y10S260/43; Y10S521/00; Y10S521/905; Y10S71/00; Y10S71/90
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
22 words
A hydroponic bed comprising an aqueous nutrient solution in intimate contact with a composite foam plant growth medium according to claim 1.
Claim 2
Dependent Claim
21 words
A composite foam according to claim 1 wherein said thermoplastic is polystyrene and said hydrophilic polymer is a partially hydrolyzed polyacrylamide.
Claim 3
Dependent Claim
86 words
In a process for hydroponically growing plants wherein a plant is supported so that its roots are immersed in an aqueous nutrient solution, the improvement which comprises supporting said plant in a composite foam plant growth medium wherein said composite foam comprises about 60 to 90 weight percent of a stable, water insoluble, open-celled foamed polyurethane matrix having intimately dispersed therein about 40 to 10 weight percent of expanded cellular thermoplastic particles and about 0.1 to 5 weight percent of a water swellable crosslinked hydrophilic polymer.
Claim 4
Dependent Claim
20 words
A process according to claim 4 wherein said thermoplastic is polystyrene and said hydrophilic polymer is a partially hydrolyzed polyacrylamide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-25 | 1977-09-24 | 1978-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-25 | 1981-09-24 | 1982-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-25 | 1985-09-24 | 1986-03-26 | $7700.00 | Window Closed / Lapsed |