Operation; Pressure Relief Procedure - Graco 238338 Operation Manual

Operation

Operation

Pressure Relief Procedure

1. Shut off air supply to the bead tank. Relieve pres-
sure from bead tank.
2. Close the master air valve (required with air-pow-
ered pumps).
3. Actuate the dispensing valve to relieve pressure.
4. Leave the drain valve(s) open until you are ready to
dispense again.
If you suspect that the dispensing valve or hose is com-
pletely clogged, or that pressure has not been fully
relieved after following the steps above, very slowly
loosen the hose end coupling and relieve pressure grad-
ually, then loosen completely. Then clear the valve or
hose.
Adjustments
Set the actuating air to at least 50 psi (3.5 bar) for single
acting gun and 80 psi (5.5 bar) for double acting gun,
then start the pump. Set the glass bead supply tank
pressure between 30 psi (2.1 bar) and 75 psi (5.2 bar)
for desired flow rate.
NOTE: Bead delivery will very with each application.
Always test the system for actual delivery and adjust air
pressure or nozzle size as needed.
4
Application Data
See RoadLazer System manual 3A1214.
Nozzle Size Selection
Use the Nozzle Size Selection and Bead Delivery
Tables to select the size of nozzle for the travel speed
and bead coverage to be used. These tables are based
on a 15 mil paint application.
1. Go to Bead Delivery (Lb/Min) Table and select:
a. Speed in MPH or KPH row.
b. Bead coverage in Pounds Per Gallon (kg/l)
column.
c. Value at intersection of MPH (KPH) row and
Pounds Per column is bead delivery in lb/min
(kg/min).
2. Go to Nozzle Size Selection Table and select:
a. Bead Delivery lb/min (kg/min) column deter-
mined by Bead delivery lb/min (kg/min) value.
b. Psi value Glass Bead Tank psi (bar) row.
c. Curve (1, 2, 3 or 4) at intersection of Glass
Bead Tank psi row and Bead Delivery lb/min
(kg/min) column is nozzle size value.
d. Select nozzle size that allows range of adjust-
ment for more or less flow.
NOTE: If dispensing reflective elements for double drop
application, the minimum nozzle size is .280 in. If a
smaller size is used, clogging of the nozzle orifice may
occur.
308612K