Background of the Invention
1. Field of the Invention
This invention relates to a gravity flow irrigation system employing flexible plastic tubing and to a method of installing the same.
2. Prior Art Relating to the Disclosure
Irrigation systems utilizing flexible conduit are known. For example, see U.S. Pat. Nos. 1,143,351; 2,595,408 and Reissue No. 14,081.
Summary of the Invention
Preformed, water-impervious, collapsible, plastic tubing is laid in a shallow trench adjacent the area to be irrigated. Spades of soil are thrown at spaced intervals over the tubing to hold it in place in the trench. One end of the tubing is connected to a source of water and the other end is restricted to control exit of water. Annular apertures are cut in the tubing at intervals along the tubing where exit of water is desired and flexible, open-ended, annular spigots extended through the apertures, allowing water to exit from the tubing. The outer circumference of the spigot has a raised annular ridge thereon which mates with a corresponding raised ridge extending around the internal surface of a matching, closed-end cap for the spigot to seal the spigot against exit of water.
Brief Description of the Drawings
FIG. 1 is an overall perspective view of the gravity irrigation system of this invention;
FIG. 2 is a perspective view of the initial step of installing the system in a field to be irrigated;
FIG. 3 illustrates the steps after extension of the preformed tubing adjacent the area to be irrigated, the steps including cutting an aperture where desired in the tubing and inserting a spigot with or without a cap in each of the cut apertures; and
FIG. 4 is a perspective view of the cap and spigot.
FIG. 5 is a side elevational view of the cap and spigot.
Description of the Preferred Embodiments
Referring to FIG. 1, preformed, flexible, collapsible plastic tubing 10 is extended adjacent the area to be irrigated and is connected at one end to a section of corrugated, reinforced, flexible pipe 11 and secured therto by suitable means, such as a metal strap, elastic band, etc. 12. The reinforced pipe 11 is connected at its free end to a planar member 13 placed across an open ditch 14 through which irrigation water flows. The water flowing throught the tubing 10 exits therefrom at spaced intervals through spigots, to be described. The exiting water flows down rows 15 of the area to be irrigated.
The preformed plastic tubing used may be any of a variety of materials but is preferably commercially available polyethylene tubing. The tubing is available in rolls having a length of 1,400 feet or more. The roll 16 of plastic tubing is suspended from an attachment 17 connected to the rear of a tractor 20. The attachment includes a plough which excavates a V-shaped trench 3 to 4 inches deep as the tractor moves along. As the tractor is pulled across the area where the plastic tubing is to be laid, the V-trench is formed by the plough portion 18 and the preformed plastic tubing laid in the trench and covered at spaced intervals by hand with mounds of dirt 19, thereby preventing the lightweight plastic tubing from being blown out of the shallow trench by the wind or pulled out inadvertently by other means. After the flexible tubing is laid, one end of the tubing is secured to the section of reinforced pipe 11, as illustrated in FIG. 1, and the reinforced pipe connected to a source of water. The opposite end of the plastic tubing is restricted to control exit of water therefrom.
Referring to FIG. 3, a cutting device 21 is used to cut annular apertures 22 in the plastic tubing 10 at desired intervals where exit of water is needed. The apertures may be cut to any size desired, depending on the amount of water needed. Annular, open-ended spigots 23 are inserted into each of the apertures for exit of water therethrough. Each spigot 23 includes an annular, open-ended body portion 24 having an inwardly directed flange portion 25 at one end and an outwardly extending flange portion 26 at the other end of greater diameter than the body. A ridge 27 extends around the circumference of the body portion at about the midpoint between flange 25 and flange 26. The outer diameter of the body portion 24 approximates the diameter of the apertures cut in the plastic tubing so that when the spigot is inserted in place, it fits snugly therein. When water is run through the tubing, the pressure of water bearing against the flange 26 prevents any significant leakage of water from the tubing around the spigot out through the intersection between the spigot and the walls of the plastic tubing.
It may be necessary at times to cap some of the water spigots with a cap 28. The cap 28 includes an annular body portion 29 terminating in a flange 30 of greater diameter than the annular body portion at one end and closed at the other end. A ridge 31 extends around the inner circumference of the body portion of the cap, this ridge mating with the ridge extending around the spigot to form a mechanical and frictional lock when the cap is placed over the spigot to prevent exit of water therethrough until desired. The cap may be removed and replaced as desired. The system disclosed is sufficiently flexible to follow the contours of a field without special fittings.
The system was designed for fast and easy installation and requires a minimum of time once in operation. The system is capable of delivering and distributing an even, continuous flow of water without need for checking and making adjustments every few hours. The cost of the system is sufficiently reasonable that if embrittled by constant exposure to weather conditions and sunlight, at the end of a growing season it may be thrown away and additional tubing purchased for the next growing season.