Kifco T40x1320 360,000 - 380,539 Operator Manual - Manual (Page 18)

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--Start Up--
After the desired depth of water has been determined and the proper nozzle has been
installed, follow the steps in the following example to set the speed: (Assume: 1.46” ring
nozzle, 120 psi inlet pressure, and a desired depth of water of 1 inch.)
1. Find the proper section in the performance Guide for the 1.46” ring nozzle. (1)
2. Locate the 122-psi inlet pressure. (2)
3. Find depth of application 1.00 inch. (3)
4. Locate 111 feet per hour. (4)
5. The water pressure on the sprinkler nozzle is 70 psi. The flow in gallons per
minute being discharged through the sprinkler is 355 and the wetted diameter is
385 feet. (5)
6. The effective irrigated width is 270 feet and the maximum effective irrigated
length is 1455 feet. (6)
7. You can also note the precipitation rate (the rate that water is being applied to
the soil) is 0.40 inches per hour. This computation is based on a 320-degree arc
of the sprinkler with the arc symmetrical to the direction of travel. See sprinkler
arc setting in this section. (7)
8. Hours required for a complete run about 13.2 can be read from the chart at the
bottom of the performance guide entitled “Retraction Speed of Irrigation Tube
(Ft/Hr)”. (8)
Note: This information is based on standard lengths of tube for the various models. Any
tube of a non-standard length or diameter will substantially charge the performance.
Consult the factory for performance information on non-standard tubes.
Speed Compensation
Speed compensation is necessary for uniform application of water. The build up of tube on
the spool gives the spool a larger effective circumference. With a constant speed of
rotation, each layer of tube on the spool makes a significant increase in the rate of sprinkler
cart retraction speed during the irrigation run. From the beginning of the irrigation run to
the end of the run the typical speed increase of a hard-hose traveler is about 40%. This
means that without speed compensation, if you set the travel speed to apply 1 inch of water
at the beginning of the run, you will get only 0.6 inches at the end of the run. On the
average, the depth is only 0.8 inches. This level of uniformity is unacceptable in most
cases.