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Technical Information - Fig No. 414

Valve Pic
°C Superheat above Saturation 50 100 150 200 250 300
Superheat factor 0.94 0.89 0.84 0.80 0.76 0.72


The chart (below) shows max. capacities for reduced pressures 58% or less than inlet pressure. Where reduced pressure is greater - multiply by given factor.

Superheated Steam capacity is reduced by multiplying by the required factor.

Both factors must be used if appropriate.

Article

The ‘ROMA’ Type R Pressure Reducing Valve is a pilot-operated, full bore, single seated valve capable of passing larger quantities of steam or air than a direct-acting type of equal size.

Control of reduced pressure is adjustable from about 90% of inlet pressure to any lower pressure above 100 kPa, and will maintain that pressure regardless of fluctuations in inlet pressure or capacity demands.

A minimum operating differential pressure of 100 kPa is required.

Dimensions (mm)

Valve Size 15 20 25 32 40 50 65 80 100
'A' 130 130 170 185 230 245 345 345 415
'B' 50 50 60 60 85 85 135 135 170
'C' 210 210 220 220 350 350 410 410 430

Operation

The reduced pressure acting upon the diaphragm balances the adjustable regulating spring loading. As the reduced pressure falls, the spring forces open the pilot valve to allow upstream pressure to be imposed upon the piston.

The piston in turn forces the main valve open, thus supplying more steam to the downstream line to maintain the required downstream setting.

The valve modulates to supply the flow requirements under actual working conditions.

Specifications

Connections 15 - 50mm BSP Female
15 - 100mm AS 2129 Flanged
Working Pressure 1400 kPa
Adjustable Ranges 100 - 400, 350 - 900 kPa

LP Over HP

Pressure Ratio 0.58 0.74 0.82 0.87 0.91 0.94 0.96 0.98 0.99
Capacity Factor 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2
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