PIETRO FIORENTINI REFLUX 819/FO, Техническое руководство

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TECHNICAL MANUAL MT103
The scope of this manual is to provide essential information for the, commissioning, disassembly, re-assembly
and maintenance of the REFLUX 819/FO regulator.
At the same time we consider it appropriate to provide a brief illustration of the main features of the regulator and
its accessories.
1.1 MAIN SPECIFICATIONS
The REFLUX 819/FO pressure regulator is a regulator for medium and high pressures.
The REFLUX 819/FO as a fail open regulator and it opens in following conditions:
- rupture of the main diaphragm;
- rupture of the pilot diaphragm;
- no feed in the pilot circuit.
The main specifications of this regulator are:
• Design pressure: up to 100 bar;
• Working temperature range: -20 °C to +60 °C;
• Ambient temperature: -20 °C to + 60 °C;
• Inlet pressure range bpe: 3 to 85 bar
• Regulating range possible Wh: 1 to 74 bar (depending on the pilot installed);
• Minimum differential pressure: 2 bar;
• Precision class RG: up to 1;
• Closing pressure class SG: up to 3.
1.2 OPERATION (FIG. 1)
In the absence of pressure, the obturator 5 is maintained in the open position by the spring 54 (fig. 1). The
upstream pressure, even if variable, does not change this position as the obturator is completely balanced and is
therefore subject to equal pressures, even if the sections are different.
The rod 6 is also between two equal pressures as the pressure upstream is also conveyed to the chamber C throu-
gh the hole A.
The obturator is controlled by the diaphragm 50 on which the following forces act:
• upwards: the load of the spring 54 and the thrust deriving from the motorisation pressure Pm in the chamber
E, supplied by the pilot;
• downwards: the weight of the mobile assembly and the thrust deriving from the regulated pressure Pep in the
chamber D.
The motorisation pressure is obtained by drawing gas from gas the regulator at the upstream pressure. The gas
is filtered through the filter 13 and is subjected to initial decompression in the preregulator R14/A/FO (fig. 2) com-
posed essentially of an obturator 5, a spring 12 and a diaphragm 10 to a value, Pep, which depends on the pres-
sure set-point of the regulator. The pressure, Pep, then passes from the chamber G through the hole F in the
204/A/FO pilot which adjusts it by means of the obturator 17 until the inlet value, Pm, in the head of the regulator.
The regulation of Pm is obtained by the comparison of the force exerted by the setting spring 22 of the pilot and
the action of the regulated pressure, Pa, acting in the chamber B on the diaphragm 16.
The set-point can be changed by turning the adjustment screw 10; clockwise rotation increases Pm and therefo-
re the regulated pressure, Pa; the opposite occurs when the ring is turned anticlockwise. If, for example, the down-
stream pressure, Pa, drops during operation (because of an increase in the requested flow rate or a drop in the
upstream pressure) an imbalance occurs in the mobile assembly 15 of the pilot, which is displaced to increase the
opening of the obturator 17.
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1.0 INTRODUCTION
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