Vacuum breakers for steam systems - Spirax Sarco

Vacuum breakers

for steam systems

Vacuum breakers

protecting equipment from vacuum damage

The Spirax Sarco vacuum breaker range will protect your plant and process equipment
against vacuum, and at the same time allow condensate to drain
effectively from pipework and storage vessels.

Low differential
pressure required to
open the valve

Stainless steel gasket Precision ground
stainless steel valve

Hexagonal body for Air connection
ease of installation

System connection A choice of either
stainless steel or
brass body and cap

How a vacuum breaker works

Normal operation Cooling At point of vacuum

Steam connection Air inlet Air in

The precision ground During cooling, steam At the point of vacuum,
stainless steel valve is begins to condense the valve will instantly lift
held firmly on its seat resulting in a reduction of its seat. The air is then
during normal operating of pressure. The valve drawn in throught the
conditions ensuring a tight remains on its upper seat upper chamber preventing
shut-off. until the pressure in the a vacuum being formed.
2 upper chamber falls below
the air inlet pressure
(usually atmospheric
pressure).

VB14 VB21

Brass Austenitic stainless steel

Size and pipe System connection ½" screwed BSP or NPT System connection ½" screwed BSP or NPT
connections Air connection 18" screwed BSP or NPT Air connection 18" screwed BSP or NPT

Materials Body Brass Cu Zn 39 Pb 2 Austenitic stainless steel AISI 303
Cap Brass Cu Zn 39 Pb 2 Austenitic stainless steel AISI 303
Gasket Stainless steel Stainless steel BS 1449 304
Valve Stainless steel BS 1449 304 Stainless steel AISI 440C
Valve seat Stainless steel Z100 CD 17
Z15 CN 16 02

Typical applications

Vacuum breaker
Air

Boiler pan

Vacuum breaker

Air

Steam mains

Applications User benefits

These robust reliable products have been used on q Protects valuable equipment from vaccum
numerous system applications preventing vacuums in damage.
equipment such as:
q Allows effective drainage from the system.
Heat exchangers Storage vessels
Boilers Jacketed pans q Simple, reliable and robust design.
Sterilizing chambers Steam mains
q Spirax Sarco's guarantee of worldwide technical
support, knowledge and service.

Our range of vacuum breakers will ensure troublefree operation whatever your needs.

3

VB14 VB21

screwed brass screwed austenitic
stainless
steel

Operating range

Temperature °C 260 Steam Temperature °C 400
saturation
200 curve 300 Steam saturation 20 21* 25
150 200 curve
100 2 4 6 8 10 12 14* 16
Pressure bar g 100
50
0 0
0 0 5 10 15
Pressure bar g

*PMO - Maximum operating pressure recommended when used for saturated steam.
The product must not be used in the red area.

Limiting conditions

Body design conditions PN16 Body design conditions PN25
Maximum allowable pressure 16 bar g Maximum allowable pressure 25 bar g
Maximum allowable temperature 260°C Maximum allowable temperature 400°C
Cold hydraulic test pressure 24 bar g Cold hydraulic test pressure 38 bar g

Capacities VB14 and VB21 Dimensions (approximate) in mm

3 A
B
2
C
Flow m³ / s 1 A (A/F) VB14 VB21
0.9 B
0.8 C 55.0 51.0
0.7 Kv 34.0 36.0
Weight (kg) 33.7 -
0.6 0.52 0.52
0.35 0.33

0.5 100 200 300 400 500
25 30 40 50
Dp (mm Hg)

Dp required to open vacuum breakers - 4.6 mm Hg VB

Spirax-Sarco Limited, Charlton House,
Cheltenham, Gloucestershire, GL53 8ER UK.
Tel: +44 (0)1242 521361 Fax: +44 (0)1242 573342

E-mail: [email protected]
Internet: www.SpiraxSarco.com

© Copyright 2000 Spirax Sarco is a registered trademark of Spirax-Sarco Limited

SB-P019-01 ST Issue 3