General Ratio Check Procedure - Graco 8900 Installation And Operation Manual

9.

GENERAL RATIO CHECK PROCEDURE

Checking the ratio allows the user to take samples of the metered material to
insure that the equipment is metering properly. On the model 8900, the ratio
check is taken by removing the spool valve and taking the material samples from
the spool valve cone check. The unit will dispense with the actuator on.
Ratio check from material cone checks: Insure that actuator for dispensing is
OFF. Unthread wing nut to remove spool valve assembly thereby exposing cone
checks. With two equal sized cups located under each cone check, actuate
system to dispense and collect sample.
NOTE: The unit meters by volume, but it is more convenient to check the
ratio by weight. It will be necessary for you to know the ratio by weight or
the specific gravity of the materials to convert volumetric ratio to weight
ratio.
Safety Glasses, proper attire including long sleeves and protective gloves are
required. Proper ventilation recommended.
a) Collect a sample amount of base and catalyst materials in identical cups.
With meter ready to operate at a moderate rate, open dispense actuate
lever, while material is flowing, PLACE CUPS UNDER FLOW
SIMULTANEOUSLY, COLLECT SAMPLE, and WITHDRAW AT SAME
TIME. CLOSE VALVES.
Weight the base and catalyst samples remembering to subtract the weight
of the cup.
b) Convert material manufacturer's ratio by "parts catalyst per 100 parts
base by weight".
100:50.
c) Divide catalyst sample weight by base sample weight.
d) Multiply the result of Step 3 (above) by 100. The product is the parts
catalyst dispensed by the machine per 100 parts base, by weight.
Installation and Operation of Model 8900 VR
For example, a 2:1 ratio (base:catalyst) becomes
9