Spirax Sarco - Catalogo Agosto 2017

Control valves

Pressure reducing/surplussing valves

Pressure/temperature limits

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Pressure bar g

The product must not be used in this region.

The product should not be used in this region or beyond

its operating range as damage to the internals may occur.

A-B-C Maximum operating conditions for steam

D-E-C Maximum operating conditions for liquids and gases

Body design conditions

Inlet

PN16

Outlet see 'Pressure setting range' below

Sizing

The required Kv can be calculated from the following formulae,

where:

Steam

saturation

curve

= Steam mass flow (kg/h)

= Liquid volume flow (m

/h)

= Gas flow at standard conditions: 0°C @ 1.013 bar a (m3/h)

= Upstream pressure (bar absolute)

= Downstream pressure (bar absolute)

- P

(pressure drop factor)

= Specific gravity

= Absolute average gas temperature (Kelvin = °C + 273)

Maximum design pressure

Maximum design temperature

Minimum design temperature

15.2 bar @ 50°C

300°C @ 9 bar g

-10°C

EPDM diaphragm 130°C

Steam Critical pressure drop:

0.58 P

Non-critical pressure drop: P

0.58 P

Gas

Liquid

Calculating the Kv and selecting a suitable valve

Using your maximum flowrate and smallest differential pressure

– P

), calculate the required Kv from one of the above formulae.

Select a valve Kv that is 30% greater than the calculated Kv. The

optimum working range of the selected valve should ideally be

within the range of 10 to 70% of its Kv.

Maximum operating temperature

diaphragm 180°C

8 bar g

-10°C

FPM

Designed for a maximum cold hydraulic test pressure of 24 bar g

Maximum operating pressure (inlet)

Minimum operating temperature

Pressure setting range

Size

Inlet / outlet

Spring range

Kv values

DN25 - DN100

PN16 / PN10

2.0 - 5.0 bar g

DN40 - DN100

DN25 - DN100

PN16 / PN2.5

PN16 / PN6

0.3 - 1.1 bar g

0.8 - 2.5 bar g

To maximise the control accuracy (especially for large load

variations) use the Kv values given at 20% offset. For safety valve

sizing use the maximum Kv values.

Valve size

Kv at 20% offset

Maximum Kv

For conversion:

Dimensions/weights (approximate) in mm and kg

DN25

DN40 DN50

DN65

DN80 DN100

3.1

4.0

Cv (UK) = Kv x 0.93

16.9 16.9

22.0 22.0

46.2

60.0

Cv (US) = Kv x 1.156

53.9 61.6

70.0 80.0

Recommended fluid velocities

Steam

Gas

Liquids

Saturated

Superheated

up to 2 bar g

above 2 bar g

10 to 40 m/s

15 to 60 m/s

2 to 10 m/s

5 to 40 m/s

1 to 5 m/s

Leakage line,

" BSP

Safety information, installation and maintenance

For full details see the Installation and Maintenance Instructions

(IM-P186-11) supplied with the product.

How to order

Example: 1 off, Spirax Sarco DN40 SRV66HC direct acting

pressure reducing valve having a pressure range of 0.8 – 2.5 bar g

and a PN16 / PN6 rating and FPM diaphragm.

Spare parts

The spare parts available are detailed below. No other parts are

supplied as spares.

Available spares

Size

DN25

100

DN40

115

DN50

125

DN65

175

DN80

175

DN100

175

Weight

Diaphragm, 'O' ring and gasket kit

10, 11, 12, 13, 17, 20

Always order spares by using the description given in the column

headed 'Available spares' and state the size, model, pressure range

and PN rating.

Example: 1 - Diaphragm, 'O' ring and gasket kit for a Spirax Sarco

DN40 SRV66HC direct acting pressure reducing valve having a

pressure range of 0.8 – 2.5 bar g and a PN16/PN6 rating and

FPM diaphragm.

138

305

2.5

How to order spares

200

345

200

355

6.5

240

690

26.0

6.5

240

690

240

690