 Fig. A Pressure Reducing Configuration Fully Closed |
 Fig. B Pressure Reducing Configuration Partially Open |
| Pressure Reducing Application (PRV) 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 FLOWGRIDtm VALVE (refer to Figure A). As demand for flow occurs in the downstream system the outlet pressure drops, causing the pilot regulator to open and start bleeding fluid out of the spring case faster than it can enter through the restrictor resulting in a reduction of pressure above the diaphragm. (Refer to Figure B). This allows the inlet pressure to progressively lift the diaphragm off the throttle plate, |
opening the valve and satisfying the demand for flow in
the downstream system. 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 A). Adjustment of the restrictor affects the response rate, stability, and sensitivity of the regulator. Smaller restrictor 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. |
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40 West Gregson Ave. Salt Lake City, Utah 84115 Phone: (801) 487-2225 FAX (801) 487-2587 E-MAIL: mail@mooneycontrols.com 
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