Table of Contents
Advertisement
Checking the Mix Ratio
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 10.
If the mixed fluid does not cure or harden properly,
check the ratio of part A to part B. To check the ratio,
relieve the pressure, flush the mixed fluid out of the
mixer, dispensing lines and equipment, then proceed
as follows:
NOTE: The pump must be operating in order to accu-
rately check the proportioning ratio of the pumps. The
outlet pressures at the pumps must be maintained at a
minimum level of 4 times that of the inlet pressures.
When the mixer manifold or other dispensing valve is
removed to check the mix ratio, a flow restrictor will be
needed to simulate the pressure conditions during nor-
mal operation. The preferred flow restrictor is a small
diameter, 1/16 in. ID, 12 in. (13 mm) long steel tube,
coupled to the fluid supply hoses. A needle-type flow
control valve could also be used. Contact your Graco
distributor for assistance in selecting the proper type of
flow restrictor for your application.
1. Disconnect the fluid hoses from the mixer inlet
valves, taking note of which hose was connected
to which valve. Then place the hose ends into a
waste container. Set two graduated cylinders of
the same size next to the waste container. See
Fig. 4.
2. Set the air pressure to the pumps at normal oper-
ating pressure. Then open the air shut off valves to
the feed pumps and proportioning pump.
3. When the fluids are flowing freely, at exactly the
same time, move the hoses over the cylinders –
part A hose over one cylinder and part B hose over
the other.
14
307132
Operation
4. When you have a large enough sample, move
both hoses back into the waste containers, at ex-
actly the same time. Then shut off the air to all the
pumps.
5. Compare part A volume to part B volume. If the
ratio is not correct, refer to the Troubleshooting
Chart on page 18 for further information on how to
correct the ratio.
6. Connect the fluid hoses back to the mixer inlet
valves.
Be sure to connect the hoses back to the same
valves they had originally been connected to. The
mixer could be damaged by reversing them.
FLUID
SUPPLY
HOSES
Fig. 4
CAUTION
MOVE HOSES AT THE SAME TIME
05229
Advertisement
Table of Contents
