(1) Field of the Invention
This invention relates to agricultural irrigation and more particularly to irrigation systems having elevated horizontal elongated pipes carrying water under pressure, moved by vehicles transverse to their length, with a plurality of sprinklers dispersing water therefrom. Those persons using agricultural irrigation systems of this type have ordinary skill in this art.
(2) Description of the Related Art
Agricultural systems using elevated horizontally elongated pipes carrying water under pressure supported by vehicles which move the pipes transversely of its length in dispensing water therefrom by plurality of sprinklers, are well known in the art. Many patents disclose such a type of system as well as them being commercially on the market. Systems are generally divided into two categories, one being designated as center pivot systems and the other being designated as a rectilinear system.
U.S. Pat. No. 4,795,100 (hereafter the '100 patent) issued Jan. 3, 1989 to PURTELLAND HOCH discloses a system using a high vibration sprinkler identified by the trademark "THE WOBBLER". As used herein high vibration sprinkler will be used to designate sprinklers such as "THE WOBBLER", which is manufactured by Senninger Irrigation, Inc. of Orlando, FL. The high vibration sprinklers are shown in U.S. Pat. No. DES. 253,364 issued Nov. 6, 1979. The '100 patent discloses the problems in mounting these sprinklers and the necessity of dampening the vibrations from them.
As a variation of the structure of the '100 patent, a loop mounting for the high vibration sprinkler has been used.
These loop holders include a rigid plastic tee at the top. The center connection of the tee is connected by a hose barb to the flexible depending hose. A 180.degree. bight shaped tube extends from each of the horizontal connections of the top tee to a bottom tee. The 180.degree. bight tubes are customarily made of PVC (Polyvinyl chloride). The bottom tee has an upward extending connection to which the high-vibration sprinkler is attached in its required upright position. Stated otherwise, the high-vibration sprinkler is placed in the middle of a 360.degree. loop with the inlet at the top.
It is known to the art to use downward sprinklers which are mounted to hang vertically below the pipe carrying water. Each sprinkler is in an inverted or downward position. In recent years the use of such types of sprinklers has been widespread. As discussed in the issued '100 patent, the preferred vibrating sprinkler does not operate satisfactory in this position.
With center pivot systems the sprinklers along the pipe distribute different amounts of water. I.e., the sprinklers adjacent to the center pivot dispense small amounts of water, usually regulated by a small nozzle in the sprinkler. The sprinklers on the distal end distribute a much greater amount of water by using a large nozzle. It will be recognized that the area of land to be watered by each length of the elevated pipe will be proportional to the distance from the center pivot. I.e., a length of the pipe which is twice as far from the pivot as a first length of pipe must distribute twice as much water as the length close to the center pivot. Likewise a length of the pipe which was 12 times as far from the center pivot must distribute 12 times as much water as the closer length. Adjustments for different water distribution may be made by changing the nozzle size of the sprinklers and by placing the sprinklers closer together.