T E C H L I N E A S ™ D E S I G N G U I D E
NETAFIM @BCL@C40BDC65.doc 21/12/2009 18
FILTERS:
Filters are installed in all irrigation systems to remove dirt and debris that could potentially
damage or block the system.
Filters are normally installed immediately downstream of the irrigation control valve.
Netafim uses a non-collapsing stack of flat grooved discs that effectively capture
contaminants.
They are easily removed from the filter body and flushed clean under a tap or in a
bucket of clean water.
Disc filters come in a variety of sizes and filtering capacities.
Rule of Thumb: Use 120 mesh or 130 micron filters for Techline AS™ designs.
Refer to “DISC FILTER SELECTION GUIDE” below to properly size the filter.
PRESSURE REGULATING VALVES (PRV’S):
Pressure Regulating Valves reduce the operating pressure so that Techline AS™ zones can
operate between 50kPa and 250kPa.
PRV’s are normally installed immediately downstream of the disc filter and control
valve.
Often all three components are installed in the same valve box and the distance from
the PRV to the Techline AS™ is limited so additional friction is not incurred.
To select the correct PRV, choose the model that has the correct flow range based on
total zone flow.
Then select the correct pressure rating based on the following:
1. If you used the “Maximum Length of a Single Techline AS™” chart, (Table 2) match
the PRV to the same pressure rating you used for your maximum lateral length
calculation,
OR
2. Simply use a 250kPa (25m) PRV. (Techline AS™ is pressure compensating; there
is no reason to intentionally reduce the pressure below 250kPa).
NOTE: If the PRV is remotely located from the supply manifold, remember to account for friction
loss that occurs through piping from the supply manifold to the PRV. Also allow for reduction or
increase to pressure within the system due to changes in the topography. An increase in
elevation of 1m will reduce system pressure by 10kPa. A decrease in elevation of 1m will add
10kPa to the system.
Example: A 2m drop in topography will increase system pressure by 20kPa.
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