US4149970A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of treating water for horticultural uses
Assignee: Fisons Ltd
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Filing: 1978-01-11
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Granted: 1979-04-17
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Expires: 1998-01-11
Abstract
Abstract The present invention relates to a method for operating a nutrient film plant growth technique so as to minimize the build up of one chemical in the circulating solution without a corresponding build-up of other chemicals, notably nutrient chemicals, therein. For example the feed of nutrient chemicals is in proportion to the feed of water to the solution, or the concentration of non-nutrients is maintained at a low level or discounted when assessing the amount of nutrient to add to the solution to maintain the desired nutrient level.
Inventors
- 👤 Peter S. Atkins
- 👤 Francis N. Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:04
CPC Classifications
A; A01; A01G; A01G31/00; A01G31/02; A01C; A01C21/00; C; C05; C05G; C05G5/00; C05G5/20; C05G5/23; Y; Y02; Y02P; Y02P60/00; Y02P60/20; Y02P60/21
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
65 words
In a process for operating a nutrient film system in which water used in the system is treated to maintain a Ca ++ content of at least 50 ppm and/or a Mg ++ content of at least 5 ppm, the improvement comprising contacting said water with a solid calcareous and/or magnesic material having a solubility of less than 5 g/liter in water at 25° C.
Claim 2
Dependent Claim
65 words
In a process for operating a nutrient film system in which water used in the system is treated to maintain a Ca ++ content of at least 50 ppm and/or a Mg ++ content of at least 5 ppm, the improvement comprising contacting said water with a solid calcareous and/or magnesic material having a solubility of less than 5 g/liter in water at 25° C.
Claim 3
Dependent Claim
26 words
A process as claimed in claim 1 wherein the solid calcareous and magnesic materials are selected from calcium carbonate, chalk, dolomite limestone, gypsum and mixtures thereof.
Claim 4
Dependent Claim
39 words
A process as claimed in claim 1 wherein only part of the water is treated and the treated water is then mixed with untreated water to reduce the concentration of Ca ++ and/or Mg ++ to the desired level.
Claim 5
Dependent Claim
22 words
A process as claimed in claim 1 wherein said water is taken from said system and recirculated thereto after said contacting step.
Claim 6
Dependent Claim
18 words
A process as claimed in claim 1 wherein the Ca ++ content is from 100 to 400 ppm.
Claim 7
Dependent Claim
18 words
A process as claimed in claim 1 wherein the Mg ++ content is from 5 to 100 ppm.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-04-16 | 1982-10-16 | 1983-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-16 | 1986-10-16 | 1987-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-16 | 1990-10-16 | 1991-04-17 | $7700.00 | Window Closed / Lapsed |