Conduction type soil matric potential sensor
First Claim
1. In a matric potential sensor, the combination comprising(a) a housing including a porous wall adapted to be located underground,(b) spaced electrodes carried in the housing to be coupled to a source of electrical current, and(c) granular material located to pass electrical current within the housing and between the electrodes so that the current flow will vary as a function of the moisture content of the granular material, said content adapted to vary as a function of the matric potential of the soil surrounding the housing in response to moisture transmission through the porous housing into the surrounding soil,(d) said sensor being located underground, and including a second and like sensor located in communication with irrigation water, and whose resistance varies as a function of exposure to moisture associated with said irrigation water, and electrical circuit means connected with said sensors to provide a comparison of the electrical resistances of said sensor, whereby the supply of irrigation water may be contolled as a consequence of said comparison.
1 Assignment
0 Petitions
Accused Products
Abstract
A matric potential sensor comprises
(a) a housing including a porous wall adapted to be located underground,
(b) spaced metal plates carried in the housing to be coupled to a source of electrical current, and
(c) granular material located to pass electrical current within the housing and between the plates so that the current flow will vary as a function of the moisture content of the granular material, said content adapted to vary as a function of the matric potential of the soil surrounding the housing in response to moisture transmission through the porous housing into the surrounding soil.
Special circuitry adapts the sensor for use with a solenoid type irrigation valve controller.
-
Citations
6 Claims
-
1. In a matric potential sensor, the combination comprising
(a) a housing including a porous wall adapted to be located underground, (b) spaced electrodes carried in the housing to be coupled to a source of electrical current, and (c) granular material located to pass electrical current within the housing and between the electrodes so that the current flow will vary as a function of the moisture content of the granular material, said content adapted to vary as a function of the matric potential of the soil surrounding the housing in response to moisture transmission through the porous housing into the surrounding soil, (d) said sensor being located underground, and including a second and like sensor located in communication with irrigation water, and whose resistance varies as a function of exposure to moisture associated with said irrigation water, and electrical circuit means connected with said sensors to provide a comparison of the electrical resistances of said sensor, whereby the supply of irrigation water may be contolled as a consequence of said comparison.
-
6. In an irrigation system, the combination comprising
(a) a soil moisture sensor whose electrical resistance varies as a function of soil moisture, (b) a second sensor for installation in communication with irrigation water, and whose resistance varies as a function of exposure to moistue associated with said irrigation water, and (c) an irrigation water flow control valve, and (d) circuit means connected with said sensors and said valve to turn the valve ON when: -
(i) the resistance of the soil moisture sensor changes to indicate a depletion of soil mositure, or (ii) a comparison of the resistances of the two sensors indicates a need for leaching of salt in the soil.
-
Specification