Nordson_EFD_781S_Installation_Guide.pdf
781S Series Spray Valve Installation Guide Electronic pdf files of Nordson EFD manuals are also available at www.nordsonefd.com Control air hose Stroke control knob Air cap retainer Fluid inlet fitting Stroke reference rin…
781S Series Spray Valve
Installation Guide
Electronic pdf files of Nordson EFD
manuals are also available at
www.nordsonefd.com
Control air
hose
Stroke control knob
Air cap retainer
Fluid inlet fitting
Stroke reference ring
Nozzle air hose
Introduction
The 781S Series precision Low Volume Low Pressure (LVLP) liquid
spray valves are designed for high transfer efficiency without overspray
or airborne mist and provide consistent coating of low- to medium-
viscosity fluids.
781S Series valves are simple to use and will operate many millions of
cycles without maintenance. Spray valve cleaning is accomplished by
purging with the appropriate solvent.
The 781S air cylinder body and fluid body are hard-coated aluminum.
The 781S-SS valve model uses stainless steel throughout.
Fluid supply line
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781S Series Spray Valve | Installation Guide
Prior to installing this valve, please read the
associated reservoir and valve controller
operating instructions to become familiar with
the operation of all components of the spray
system.
1. Connect the fluid supply line to valve.
2. Connect the fluid supply line to the reservoir.
3. Connect the control air hose and the nozzle
air hose to corresponding outputs on
solenoid block.
4. Fill reservoir by pouring fluid directly into
tank liner or manufacturer’s bottle placed
inside reservoir. Secure cover prior to setting
pressure.
5. Set reservoir pressure to low for thin fluids
and higher for thick fluids.
6. Using the Mode button on the ValveMate
controller, place the controller in the PURGE
mode. In PURGE mode
only, channels and can be
selected independently without nozzle air
pressure.
7. Using the needle stroke control knob on
the 781S valve, set the fluid flow rate to
one or two drops per second. Check the
flow rate by actuating the controller in the
time override mode. Make valve stroke
adjustments when the controller is off.
8. Set the nozzle air pressure on the nozzle to
0.7 bar (10 psi) and actuate the controller.
The valve will produce a fine spray. To
change fluid flow, use the needle stroke
control knob and / or reservoir pressure.
To change nozzle air, use the nozzle air
pressure regulator. Higher pressures will
provide finer spray.
Installation
NOTE: The area of spray coverage is determined by the distance between the spray valve nozzle and the work surface.
Refer to the charts on the back page to determine this distance.
SPRAY VALVE CONTROLLER
8040
EFD 781S
EFD 781S
3
6
5
8
2
4
1
7
Open
Close
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781S Series Spray Valve | Installation Guide
How the Valve Operates
Input air pressure at 4.8 bar (70 psi) retracts the needle
1
from its nozzle seat,
2
allowing liquid to flow from the
nozzle. At the same time, nozzle air is turned on and flows
from the anannulus
3
around the liquid nozzle. This
adjustable nozzle air creates a pressure drop around the
nozzle, causing the liquid to atomize into fine droplets.
The amount sprayed is controlled by the valve open time,
reservoir pressure, and needle stroke*. Area of coverage
is determined by the nozzle size and the distance
between the nozzle and work surface.
ValveMate Concept
The ValveMate
™
8040 provides easy adjustment of
spray valve output for maximum end-user convenience
and efficiency. Valve open time is the primary control of
deposit size. The ValveMate 8040 puts adjustment of
valve open time where it needs to be — near the spray
valve.
External solenoids, combined with a 0–2bar (0–30psi)
nozzle air pressure regulator, provide Low Volume
Low Pressure (LVLP) air to the nozzle, for high transfer
efficiency.
NOTE: Order your single or dual valve solenoid
assemblies separately. Consult Nordson EFD for
recommendations.
The primary control of deposit size is the valve open time.
closed open
1
2
3
1
2
3
Calibration Feature
The stroke control reference ring of each 781S-SS valve
is factory calibrated to the zero position. After cleaning,
disassembly and reassembly, the stroke control zero position
may require recalibration. To do so:
1. Make a note of the current
stroke setting number.
2. Turn the calibration
adjustment knob (inner)
counterclockwise two full
turns.
3. Turn the stroke knob (outer)
clockwise until it stops.
Note reference ring “0”
(zero) location. If “0” is not
positioned above either
reference mark on air cylinder body, rotate outer stroke
knob counterclockwise until “0” is positioned above
preferred referencemark. Select reference mark that is
more clearly visible based on valve mounting location.
4. Insert 1/8" hex allen wrench (included) into calibration
adjustment knob.
5. Turn the calibration adjustment knob clockwise until it
stops. The stroke adjustment is now calibrated to zero.
6. Reset stroke to the required position noted in step 1.
4
2 5
16
3
*The 781S valve can be ordered in a tamper-resist
configuration to limit unauthorized adjustment. Specify
part #7021616.