Abstract An irrigation control apparatus, particularly suited to drop-by-drop irrigation, is provided and which comprises an assembly for electrically controlling the starting and stopping of an irrigation system by means of two electrodes which are spaced both vertically and laterally from each other. A "bulb" of humid soil is produced during irrigation and the upper electrode of the two is laterally off-set with respect to the axis of symmetry of the bulb, by a distance equal to at least half of the maximum radius of the bulb, and is situated at the upper limit of the bulb. The lower electrode of the two is arranged in a diametrically opposite position, at a point laterally off-set with respect to the said axis, but in the inverse sense, also by at least half the maximum radius of the bulb and is situated at the lower limit of the bulb. The precise relative positions of the electrodes are determined by the shape of the bulb which in turn depends on the nature of the soil to be irrigated.
An improved irrigation control apparatus, comprising an assembly electrically controlling the starting and stopping of an irrigation installation through the agency of two electrodes measuring the electrical resistance of the soil, the said two electrodes being simultaneously spaced from one another laterally and vertically, the improvement comprising an upper electrode placed at a point which is laterally offset with respect to the axis of symmetry of the bulb formed by drop by drop irrigation, at a distance equal to at least half of the maximum radius of the bulb and situated at the upper limit of the said bulb; and a lower electrode disposed in a diametrically opposite position, at a point laterally offset in the inverse sense by at least half of the maximum radius of the bulb and situated at the lower limit of the said bulb.
Claim 2
Dependent Claim
139 words
An improved irrigation control apparatus, comprising an assembly electrically controlling the starting and stopping of an irrigation installation through the agency of two electrodes measuring the electrical resistance of the soil, the said two electrodes being simultaneously spaced from one another laterally and vertically, the improvement comprising an upper electrode placed at a point which is laterally offset with respect to the axis of symmetry of the bulb formed by drop by drop irrigation, at a distance equal to at least half of the maximum radius of the bulb and situated at the upper limit of the said bulb; and a lower electrode disposed in a diametrically opposite position, at a point laterally offset in the inverse sense by at least half of the maximum radius of the bulb and situated at the lower limit of the said bulb.