Operation
B 4-4
Part 1022914G03
E
2007 Nordson Corporation
Startup
(contd)
2. Start the pump by opening the air shutoff valve (1) and adjusting the air
pressure regulator (2) to the air pressure that will produce the desired
output pressure.
3. Purge air from the system:
S
Dead-end system: Trigger the spray guns and watch for spitting as
air is purged. Stop when the spray pattern is continuous and even.
S
Circulating system: Close the circulation valve (8) and open the
drain valve (9). Watch the flow from the drain rod (10). When no
more air bubbles are seen, shut the drain valve and slowly open the
circulation valve until the pump is running at the desired number of
cycles per minute. Trigger the spray device(s) to purge air from
them.
NOTE:
The more the circulation valve is opened, the more potential
there is for fan pattern collapse or “wink” at the spray device when the
pump changes direction or shifts. Open the circulation valve just
enough to maintain the required fluid temperature and agitation in the
circulation loop.
4. Turn on the fluid heaters (7), if used, and watch the thermometer at the
heater outlet. Circulate coating material through the heater until it is at
desired temperature before spraying parts.
NOTE:
Overheating coating materials can cause cavitation in the pump
if the solvents in the coating material boil out in the vacuum created
during the siphon cycle. If this happens, lower the heater thermostat
setting. Refer to
Section B5 Troubleshooting
for more information.
Routine Shutdown
1. If fluid heaters (7) are used, turn them off 10 to 15 minutes before
shutting down the pump. This prevents coating material from curing
inside the heaters.
2. Stop the pump by closing the air shutoff valve (1) or adjusting the air
pressure regulator (2) to zero.
3. Relieve the system hydraulic pressure by triggering the spray guns or
opening the drain valve (9).
NOTE:
Normally, you can leave the system filled with coating material
overnight. If the material contains solids that easily settle out, circulate
material through the system for several minutes before beginning
production the next day. Do not leave the system open to air, as the coating
material could cure and clog the system. If the system will be shut down for
more than a few days, flush it and leave it filled with cleaning solution.
4. Perform daily maintenance as described in
Maintenance
in this section.
