Avoiding Pulsation When Simultaneous Dispensing Fluid; Selecting A Supply Pump - Graco Horizon Fluid Management Systems Instructions Manual

System Dynamics And Design Factors
Avoiding Pulsation When Simultaneous
Dispensing Fluid
When simultaneously dispensing fluid, check valves (I)
and pressure relief valves (J) need to be installed at
each pulse meter (G) to prevent false readings on one
meter while other meter, solenoid (B), and valve com-
binations are actively dispensing. See Fig. 24.
These false readings occur when one or more reels
are actively dispensing and another reel is authorized
to begin dispensing the same fluid. The fluid solenoid
(B) to this newly activated reel is now open and waiting
for the operator to open the valve. Its pulse meter (G)
is also activated and ready to begin counting pulses.
Because the hose is expandable, fluid can flow in and
out of it when the other operators open and close their
valves and the pump operates. As this fluid moves
back and forth through the pulse meter (G), the meter
generates pulses which the system interprets as actual
dispensing. Check valves (I) will prevent pulsations
from reaching the pulse meters and creating false
readings.
*Potential for pulsation and over-pressurization if
check valves are not installed. Read Warning, above.
Fig. 24
106 308607
WARNING
To reduce the risk of serious injury, the
pressure relief valves (J) are required to
prevent the system from over-pressuriz-
ing, which could be caused by thermal expansion
of the fluids. See Fig. 20. See page 80 to order the
valves.

Selecting a Supply Pump

If multiple reels will be dispensing fluid at the same
time, a higher capacity pump is needed. The size of
the pump (based on the volume of fluid delivered) can
be computed by taking the expected flow rate from
each valve, times the number of valves that could
dispense simultaneously.
J*
I
G
B
06516