Trigger Air Connection; Optional Air-Release Valve; Optional Quick Exhaust Valve - Nordson A7A Customer Product Manual

8
A7A Single and Dual Automatic Airless Spray Guns

Trigger Air Connection

Part 1072640A
Use an electro-pneumatic solenoid valve to trigger the gun. For the fastest
trigger response, connect the solenoid valve directly to the gun at the
1
/ -in. NPT air inlet fitting. If this is not possible, install the valve as close to
8
the gun as possible, and use the shortest length of air tubing possible.
NOTE: If the trigger air tubing is too long, it can cause trigger on/off delays,
spitting, and premature wear of the ball or needle and seat. If you cannot
shorten the air tubing, install an optional air-release valve on the gun.

Optional Air-Release Valve

See Figure 4. Refer to Options on page 15 for the air-release valve part
number. The air-release valve
S
reduces the cycle time of the A7A gun, if the speed of operation is less
than 600 cycles per minute.
S
may be used when the electro-pneumatic solenoid valve cannot be
installed on the gun. With this option, 100-ft air line lengths are
practical.
S
reduces wear on the ball or needle and seat if operating the gun at high
speed.
S
allows one solenoid valve to trigger several guns.
S
provides precise gun triggering from a remote timer, eliminates poor
gun/timer resolution, and saves coating material.
NOTE: The trigger air pressure must remain constant. Limit the diameter
of the pilot air lines (5) to prevent spitting and other problems.
1 2 3
Figure 4 Typical Air Release Valve Installation
1. Filter
2. Gauge
3. Lubricator
4. Solenoid valve

Optional Quick Exhaust Valve

The optional quick exhaust valve will allow the gun to close faster and
reduce overall cycle time. Use a
1
the gun, and a / -in. tube x
4
tubing to the valve. Refer to Options on page 15 for the exhaust valve and
fittings.
4
7
5
5. Small diameter pilot air line
6. Air-release valves
7. Trigger air supply line
(2.7−4.1 bar (40−60 psi)
1
/ -in. NPT nipple to connect the valve to
4
1
/ -in. NPT fitting to connect the actuating air
8
6
1300453A
E 2019 Nordson Corporation