Operation; Sequence Of Operation - Graco PD44 Operations & Parts List

Operation

Operation
The operation of the PD44 metering valve is controlled
by an external source.

Sequence of Operation

Step 1: Reload
• Spools shift to the right
• Material feed inlets (A,B) are opened
• Materials are transferred into the metering cham-
bers by a pressurized feed system
• Outlet ports are blocked
• Metering rods (E) are retracted to a precise position
determining the volume of each material
Step 2: Shift
• The balanced spool assemblies shift to the dis-
pense position
• Material path to the mixer inlet is opened
• Material feed inlet ports (A,B) are blocked
• Metering rods (E) remain in the retracted position
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Step 3: Dispense
• Metering rods (E) extend
• A and B materials are simultaneously dispensed
from the metering chamber into the disposable
mixer
• A and B materials are dispensed at the predeter-
mined volume ratio.
Upon completion of the dispense stroke, the metering
rod (E) and spool assemblies shift back to the reload
position.
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