FAQ

The software calculates two types of uniformity coefficients:

(Wu et Al. [1979])

Where Qi is the flow rate of a single spout, Qm is the average value and N is the number of spouts.

• UCC = 100 the uniformity of the plant is excellent
• UCC < 90 plant uniformity is not acceptable

(Karmeli and Keller [1975])

Where CVT is the coefficient of technological variation, Qmin the minimum flow rate in a dispenser and Qm the average flow rate.

• CU = 100 the uniformity of the plant is excellent
• 94 < CU < 100 plant uniformity is good
• 90 < CU < 94 plant uniformity is acceptable
• CU < 90 plant uniformity is not acceptable

Efficiency is defined by the following formula: Ei = qmin⁄qmed * 100*A (where A is an internal, very complicated to explain factor that also depends on uniformity). Theoretical value where qmin is the minimum flow rate and qmed is the average value. The maximum efficiency value in a drip system is 87%, in a sprinkler system it is 75%. The lower the value, the lower the efficiency. The wasted volume is zero if the efficiency is 100% (only theoretical, you will always have a wasted volume > 0)

The most restrictive criterion in hydraulic calculation is the thematic map. The range of acceptability is -10% < average or nominal pressure < +10%, so the yellow colored area is still to be considered acceptable. A plant showing a thematic map without the red color demonstrates a higher uniformity value than that expressed by the uniformity coefficient > 90%.

Discretization refers to the grouping of multiple spouts at one point to speed up hydraulic design and calculation. For example, with very high discretization the software will group 12 dispensers into 1 dispenser having 12 times the flow rate of the single dispenser. With this type of discretization in the bill of materials there may be a 2-5% difference in the length of the side pipes compared to the non-discretized case.

The “elevation point” or “contour line” commands are used to create the 3D terrain model. At least 4 points must be entered for processing, but this number may increase depending on the extent of the plot area. It is recommended to draw the boundaries of the areas before using the command. Once the input is finished, press the ESC key and the software will show the processed contour lines and present the third Z coordinate (shown by scrolling with the mouse over the work area). The “elevation point” and/or “contour lines” can be imported and interpreted from the CAD files containing them. “Recalculate quotas” is useful for performing a refresh or update of quotas.

Depending on the area surveyed with Google’s service, the accuracy of the elevation data varies from 3 arc-seconds (1 point surveyed every 90 meters) to 1/3 arc-second (1 point surveyed every 10 meters), up to 1/9 arc-second in U.S. and many urban areas (1 point surveyed every 3 meters). The processing, both elevation and planimetric, returned in Software is equivalent to a 1:5,000 map (as error on elevation), and Google’s service is getting better every day. Recall that Google’s GIS service is already successfully used by engineering and surveying programs.

You cannot edit or partially delete contour lines (once imported and interpolated into the workspace) because they constitute the 3D terrain relief. It is possible to delete or replace the survey (with new contour lines) by making a new survey from the Google Maps console or by importing a CAD file with different contour lines. It is also possible to use the UNDO and REDO commands to return to an earlier or later condition.

In-line emitter (dripper)

Where:

delta = Coefficient of local losses

Dci = inner diameter of the tube

Dgi = Inner diameter of the nozzle

Online dispenser

Where:

delta = Coefficient of local losses

r = Ar/A throttling ratio

Ar = Reduced area at the dispenser

A = Area of the tube

In the case of sprinkler delta = 0

As the sum of the pressure drop between the source and the farthest spout

The volume actually used in one hour minus the volume used under ideal efficiency conditions