Graco 8900 Installation And Operation Manual page 16

Installation and Operation of Model 8900 VR
e) Compare the weight ratio obtained to the desired weight ratio. Repeat to
obtain several successful ratio checks.
troubleshooting guide later this section
PARTS BY VOLUME (PBV) TO PARTS BY WEIGHT (BPW)
Parts Catalyst by Volume
Parts Base by Volume
Catalyst Sample Weight LESS Cup Weight
Base Sample Weight LESS Cup Weight
Product = Parts Catalyst per 100 Parts Base
Manufacturer's specified weight ratio = 4:1 or 100:25.
Weight of base in ratio check is 245 grams
Weight of catalyst in ratio check is 61.2 grams.
61.2 divided by 245 (61.2/245 = .2497) equals .2497.
.9497 x 100 = 24.97 parts catalyst per 100 parts base.
Three ratio checks are recommended to insure accuracy at final setup.
The presence of any air (visible or not visible) in the material or system
will result in inaccurate ratio checks. If the ratio check cannot be made
with repetitive accuracy, review ratio setting procedures.
NOTE: Some materials contain substantial amounts of entrained air;
due to manufacturing, transportation, set-up of system; or run
change. It must be removed (through degassing, recirculation, or
self removal over time) before accurate
accomplished.
NEXT STEP: START UP PROCEDURES
EXAMPLE
CONVERSION FORMULA:
X Specific Gravity Catalyst
Specific Gravity Base
X = 100:Parts catalyst by weight
RATIO CHECK EXAMPLE
10
If not metering on ratio, see
x 100 = X
x 100 = Product
metering can be