Technical Information - Fig No. 414

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

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.

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

Capacity Factor

0.58

1.0

0.74

0.9

0.82

0.8

0.87

0.7

0.91

0.6

0.94

0.5

0.96

0.4

0.98

0.3

0.99

0.2

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