Principles Of Operation - GE Mooney Flowgrid Instruction Manual

Principles of Operation

Pilot Supply
Restrictor
Pilot Loading
Connection
Inlet
Figure 4 - Pressure Reducing Configuration Fully Closed
At no flow, when the outlet pressure is greater than the
set point of the pilot regulator, the pilot is closed and full
inlet pressure loads the spring case through the pilot
loading connection. In this condition the diaphragm is
closed tightly against the throttle plate. The pressure
differential across the outlet half of the diaphragm adds
to the spring force in closing the Flowgrid regulator
(Refer to Figure 4).
As demand for flow occurs in the downstream system
the outlet pressure drops, causing the pilot regulator to
open and start bleeding pressure out of the spring case
faster than it can enter through the restrictor. Reducing
the pressure above the diaphragm allows the inlet pres-
sure to progressively lift the diaphragm off the throttle
plate, opening the regulator and satisfying the demand
for flow in the downstream system. (Refer to Figure 5).
Pilot Supply
Restrictor
Pilot Loading
Connection
Inlet
Figure 6 - Back Pressure Configuration Fully Closed
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Pilot Sense
Connection
Pilot Outlet
Connection
INLET
Outlet Inlet
Figure 5 - Pressure Reducing Configuration Partially Open
When demand for flow ceases or is reduced, the
downstream pressure increases causing the pilot
regulator to close. Inlet pressure continues to pass
through the restrictor until the control pressure equals
the inlet pressure. The spring force, plus the pressure
differential across the outlet half of the diaphragm
closes the diaphragm against the throttle plate, shutting
off the flow (Refer to Figure 4).
Adjustment of the restrictor affects the response rate,
stability, and sensitivity of the regulator. Smaller restric-
tor openings result in higher gain (sensitivity) and slower
closing speeds. Larger openings result in lower gain
(greater proportional band), greater stability and faster
closing speeds.
Pilot Sense
Connection
Pilot Outlet
Connection
Inlet
Outlet
Figure 7 - Back Pressure Configuration Partially Open
Pilot Supply Pilot Sense
Connection
Restrictor
Pilot Loading
Connection
Pilot Outlet
Connection
Pilot Supply
Pilot Sense
Connection
Restrictor
Pilot Loading
Connection
Pilot Outlet
Connection
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Outlet
Outlet