Patent US3824844A successfully refreshed from Google Patents.
US3824844A
Expired / Lapsed
US
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Soil moisture monitor
Assignee: Water Rite Inc
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Filing: 1973-05-11
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Granted: 1974-07-23
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Expires: 1993-05-11
Abstract
Abstract An inexpensive device is provided for sensing the moisture content of soil, particularly around house plants. The device has a dark colored background with a thin, permeable hydrophilic film in front of it. The film is protected by a transparent plastic layer in front and the assembly is heat sealed together. A hole is pierced through the protective layer for giving the permeable film access to soil moisture. The permeable film is preferably a sheet of light colored, single ply facial or toilet tissue which has high reflectivity and low transmission of light when dry but which becomes quite translucent when wet. The extent of dark colored background exposed by the wet film indicates soil moisture content.
Inventors
- 👤 R Strickland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:46
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22; G01N31/222; E; E02; E02D; E02D1/00; E02D1/02; E02D1/027; G01N33/00; G01N33/24; G01N33/246
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
56 words
A soil moisture monitor comprising: a dark colored background layer; a light colored hydrophilic permeable film in front of the background, said film having relatively low light transmission when dry and relatively high light transmission when wet; means for exposing a portion of the film to moisture; and a transparent protective cover over the permeable film.
Claim 2
Dependent Claim
56 words
A soil moisture monitor comprising: a dark colored background layer; a light colored hydrophilic permeable film in front of the background, said film having relatively low light transmission when dry and relatively high light transmission when wet; means for exposing a portion of the film to moisture; and a transparent protective cover over the permeable film.
Claim 3
Dependent Claim
39 words
A moisture monitor as defined in claim 1 wherein the dark colored background layer comprises: a substantially rigid water resistant protective layer on the outside; and a soft, lower melting interlayer between the permeable film and the protective layer.
Claim 4
Dependent Claim
30 words
A moisture monitor as defined in claim 2 wherein the permeable film is sufficiently thin that plastic from the interlayer can flow therethrough when molten and contact the protective cover.
Claim 5
Dependent Claim
16 words
A moisture monitor as defined in claim 3 wherein the permeable film comprises a paper tissue.
Claim 6
Dependent Claim
48 words
A moisture monitor as defined in claim 4 wherein the background layer and protective layer are sealed together around the edges through the tissue; and wherein the means for exposing an edge portion of the film comprises a hole through the moisture monitor displaced from an end thereof.
Claim 7
Dependent Claim
73 words
A soil moisture monitor comprising: a water resistant protective sheath having a transparent portion and a dark colored background behind the transparent portion; a hydrophilic permeable film between the transparent portion and the background, said film having relatively high light reflectivity and relatively low light transparency when dry and relatively low light reflectivity and relatively high light transparency when wet; and an aperture through the sheath for exposing a portion of said film.
Claim 8
Dependent Claim
73 words
A soil moisture monitor comprising: a water resistant protective sheath having a transparent portion and a dark colored background behind the transparent portion; a hydrophilic permeable film between the transparent portion and the background, said film having relatively high light reflectivity and relatively low light transparency when dry and relatively low light reflectivity and relatively high light transparency when wet; and an aperture through the sheath for exposing a portion of said film.
Claim 9
Dependent Claim
20 words
A laminated soil moisture monitor as defined in claim 6 wherein the permeable film comprises a single ply paper tissue.
Claim 10
Dependent Claim
55 words
A laminated soil moisture monitor as defined in claim 6 wherein said sheath comprises a pair of outer layers of transparent, relatively rigid plastic and a relatively softer, lower melting point plastic interlayer therebetween having its edge portions heat sealed to the pair of outer layers, including at least a portion sealed through the tissue.
Claim 11
Dependent Claim
49 words
A laminated soil moisture monitor as defined in claim 6 wherein the sheath comprises a pair of outer layers of substantially rigid plastic and said film is sufficiently thin and premeable for passing a sealing agent therethrough between the faces of the sheath around the periphery of the monitor.
References Cited (Backward Citations)
US3019638A
Cited
US3414415A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |