This invention relates primarily to sprinklers especially those for agricultural uses.
The effectiveness of sprinklers can be judged by a number of different factors. The first factor is the water distribution pattern. Ideally, the amount of water per unit area would be directly proportional to the distance from the sprinkler. For example, an ideal sprinkler may provide 2 liters of water per given area at the sprinkler, 1.5 liters at 10 feet (3 m) from the sprinkler, 1 liter at 20 feet (6 m), 0.5 liters at 30 feet (9 m) and no water at 40 feet (12 m), the falloff in the amount of water would be relatively constant over distance. Then, a second sprinkler could be mounted approximately 40 feet (12 m) from the first with the same distribution pattern so that the second sprinkler would add 2 liters of water 40 feet (12 m) from the first sprinkler, 1.5 liters at 30 feet (9 m) from the first sprinkler, 1 liter at 20 feet (6 m), 0.5 liters at 10 feet (3 m) and no additional water at the first sprinkler. Adding the water that both sprinklers provide yields 2 liters per given area over the entire field, and even watering is ideal.
Metric conversions of inches, feet and pounds are approximations and are frequently rounded off.
Unfortunately, prior art sprinklers have large amounts of variability in their distribution pattern. There are peaks and there are depressions in the distribution curve. Certain nozzles may have extremely low distribution in the center of their distance. If the low point coincides with the low point of an adjacent sprinkler, certain field areas will receive less than the necessary amount of water. Likewise, other areas may receive too much water.
One of the problems with prior art nozzles is in causing the fluid flow to break from a narrow stream, and one of the objects of the present invention is to disclose and provide a nozzle which does disburse the main stream.
Some prior art nozzles attempt to break the main stream by use of elevated pressures. For example, it is not uncommon to run agricultural sprinklers at 60 to 70 psi (4218-4920 g/cm.sup.2). High pressures create two major problems. First, there is a substantially larger energy consumption in high pressure systems than in lower pressure ones. The cost of power for irrigation is not insubstantial. For example, in California's Central Valley, large farms spend over one million dollars for power for irrigation. Much of the power is obtained from hydro generators driven by the irrigation water itself as it flows from the snowpack in the Sierra Nevada Mountains. That power could be used elsewhere, however, if it were not necessary for agricultural uses.
A second problem deals with droplet size. It is believed that in the high pressure systems, an extremely small droplet size is obtained. Therefore, during sprinkling more water is vaporized and less falls on the ground. This wastes precious water by itself, but the effects of such wastefullness are compounded. Because less water reaches the field in a given period of time, the length of watering must be increased often into the high temperature, low humidity daytime, climatic conditions that are relatively common in the western United States. Under these conditions, much of the irrigation water evaporates either from the sprinkler or as it is lying on the ground before it can penetrate the soil. Therefore, it is an object of the present invention to disclose and provide a sprinkling system that can operate under lower pressures so that droplet size can be increased, distribution of water over time can be increased, and pressure and power consumption can be reduced.
The nozzle of the present invention is designed to operate at approximately 30 psi (2109 g/cm.sup.2), and as described in more detail hereinafter, it distributes more water in a more even distribution than a standard one delivers at its higher pressure.
The orifice of this sprinkler is larger than the diameter of nozzles of standard sprinklers, but because of the decreased efficiency of orifices relative to nozzles, excessive amounts of water are not delivered. The larger orifice passes debris that would otherwise clog smaller orifices or nozzles. Also, the buildup of deposits of salts is less critical in a large nozzle than in a small one. Therefore, it is an object of the present invention to disclose and provide a nozzle which can utilize a larger orifice for prevention of clogs from debris.
Another object of the present invention is to disclose and provide a low cost nozzle. In some prior art nozzles, the housing and orifice plate are one piece of material. It is advantageous to make the orifice plate of wear resistant material such as stainless steel or carbide for resistance of wear from water passing through the orifice. However, there is no necessity that the orifice housing be of wear resistant material; to do so increases the cost. It is beneficial, therefore, to make the orifice housing out of low cost brass or plastic.
The present invention also solves additional objects that will become evident in the foregoing specification.