NP30A or NP40A
Metering Overview
25
2019-03-11
407-502M
A37.Section Control Relief Valve
(Section Control Option Only)
In normal operation, this valve never activates.
NH
3
can get trapped in the system between the
section control check valve
and the section
shut-off valves
, if all section valves are closed
while the system is charged. As the liquid warms
and pressure rises, this relief valve protects the
system with periodic releases.
This valve is set to activate at 350 psi.
Operator action is periodic inspection, and to
replace this hydrostatic relief valve, a time-dated
part, when it reaches the end of its operating life
” on page 119 for maintenance.
A38.Section Flow Divider
(Section Control Option Only)
This is a CDS-John Blue
®
Impellicone
®
manifold.
It evenly splits the NH
3
flow for distribution through
the row flow dividers
. There are no operational
items for this component.
A39.Section Shut-Off Valves
(Section Control Option Only)
These are the normal controls for suspending
per-section application flow in the field (for point
rows, pass overlap, etc.). These are open/close
solenoid valves controlled by the “BOOMS”
switches on the SCS 450.
When used with the SCS 450 or other suitable
sectional application controller, shutting off a section
causes the total flow to be reduced by
1
/
3
of the
all-sections-on rate, keeping the rate constant for
the section(s) still active.
Each section valve has a visible indicator above the
valve ball casing, indicating whether open or closed.
Operation of each section valve is essentially
instantaneous. However, there is considerable
residual NH
3
in the section flow divider and delivery
tubes after shut-off. When console power is off, the
valves remain at their most recent setting.
The valve balls are equipped with a downstream
relief orifice.
A40.Row Flow Divider(s)
This is a CDS-John Blue
®
Impellicone
®
manifold. It
evenly splits the NH
3
flow for distribution through
the delivery tubes
. There are no operational
items for this component.
A41.Flow Divider Manifold Inlet
NH
3
liquid flow enters the flow divider here.
A42.Flow Divider Pressure Gauge
This gauge reports the pressure prior to flow
division. It normally reads lower than the cooler and
nurse tank pressure gauges.
A43.Flow Divider Outlet
Each of these ports receives an equal fraction of the
NH
3
liquid flow.
A44.Flow Divider Plug
Unused ports are plugged with a steel NPT plug.
Unused ports do not affect flow balance at the other
ports.
A45.Delivery Tube
This tubing passes NH
3
liquid flow to the knives or
tines. Operator action is to replace this tubing, a
time-dated part, when it reaches the end of its
operating life. See page 123.
A46.Knife or Tine (Single)
Knives and tines open a furrow and inject the liquid
NH
3
. Tines inject the liquid in the furrow opened by
the anhydrous coulter. All but two (or four) of the
rows are equipped with knives or tines having a
single smaller liquid delivery tube. Knives and tines
need frequent inspection for wear and damage.
A47.Cooler Vapor Outlets (2)
Two vapor outlets direct the now-gaseous
refrigerant flow (that entered at
) to two special
knives or tines
per cooler.
A48.Vapor Tube
This tubing passes NH
3
vapor flow to the dual
knives or dual tines. Operator action is to replace
this tubing, a time-dated part, when it reaches the
end of its operating life. See page 123.
A49.Knife or Tine (Dual)
There are two of these special knives or tines per
cooler (four total on a dual-cooler applicator). They
direct the vaporized refrigerant NH
3
gas into the soil
at the larger rear vapor tube. They are otherwise
identical to the single-tube knives and tines
.
