GREAT PLAINS NP2540, Operator'S Manual, Page: 153 / 196

NP2540 Table of Contents Index Options 149
2019-04-12 Table of Contents Index 417-459M
VisaGage and Accessories
Liquid fertilizer manifolds are not standard. Select one or
two booms and attachment kits depending on row tines
installed. Order pumps separately.
Manifolds
Manifolds are installed before delivery if ordered (as
options) with the applicator. If a pump is also ordered,
only the front manifold is plumbed to the pump.
Manifolds include drop lines, but not row tines.
Fertilizer Orifice Plates
The manifold systems, and the side dress accessory
include size 28, 34 and 48 plates. To order alternate
plates, use the table on page 145. Order one per row
unit.
Select and Install Orifice Plates
If using VeriFlow nozzles, orifice plate instructions do not
apply. However, the topic “ Tramlines and Doubled
Rows ” on page 98 applies to all types of nozzles.
Agricultural Chemical Hazard:
Wear protective gloves when changing orifice plates. Consult
material manufacturer or supplier documents for proper
handling and steps to take if skin contact occurs.
Refer to Figure 98
Orifice plates at each drop line nozzle provide
back-pressure that balances flow in the manifolds,
assuring that each row obtains the same flow rate. For a
given rate, there may be more than one orifice size that
provides the recommended back-pressure.
Plates are provided with the system in three sizes.
Additional sizes are available. In general, the orifice
needs to be small enough to create a minimum pressure
in the manifold but large enough to prevent the manifold
pressure from exceeding the maximum:
15 psi min., 15-40 optimal, 65 psi max.
Using an orifice size too large can result in unequal flow
at rows. Using a size too small can cause excess
back-pressure resulting in material dumping at the relief
valve.
Determine Orifice Size
The chart below shows rate ranges for each Great Plains
orifice size and row spacing. You may need to change to
the next higher or lower orifice for a different fertilizer
solution density and/or a different ground speed.
To reduce orifice plugging and pump wear, use the
largest orifice practical for your fertilizer application
rate.
Material Loss or Misapplication Risks:
Orifice size must be appropriate for rate selected. Drop line
orifice plates do not affect rate . If orifice size is too small,
over-pressure in system may result in material loss at relief
valve. An orifice size too large may result in uneven
application across all rows.
Figure 98
Fertilizer Drop Line Nozzle
36715
1
1