Spirax Sarco - Catalogo Agosto 2017

Pipeline ancillaries

Vacuum breakers

Description

The VB21 is a small purpose designed vacuum breaker for general

purpose applications on condensing vapour (steam) or liquid systems.

Standards

This product fully complies with the requirements of the European

Pressure Equipment Directive 97/23/EC.

Certification

This product is available with a manufacturer's Typical Test Report.

Note: All certification/inspection requirements must be stated at

the time of order placement.

Sizes and pipe connections

1⁄2" (system connection) screwed BSP or NPT.

" (air inlet connection) screwed BSP or NPT.

Pressure/temperature limits

��

VB21

Steam

saturation

curve

��

Pressure bar g

The product must not be used in this region.

Body design conditions

PMA Maximum allowable pressure

TMA Maximum allowable temperature

Minimum allowable temperature

PMO

Maximum operating pressure

for saturated steam service

TMO Maximum operating temperature

Minimum operating temperature

PN25

25 bar g @ 120°C

400°C @13 bar g

-48°C

21 bar g

400°C @ 13 bar g

0°C

Note: For lower operating temperatures consult Spirax Sarco

Designed for a maximum cold hydraulic test pressure of 38 bar g

Dimensions/weight (approximate) in mm and kg

Materials

No.

Part

Cap

Valve

Body

Gasket

Size

1⁄2"

B (A/F)

0.52

Weight

0.33

Material

Stainless steel

AISI 303

AISI 440 C

AISI 303

AISI 304

breaker 4.6 mm Hg

Capacity Dp required to open vacuum

��

Safety information, installation and maintenance

For full details see the Installation and Maintenance Instructions

(IM-P019-05) supplied with the product.

Installation note:

The VB21 vacuum breaker must be installed in a vertical position

with the system connection at the bottom. On steam systems, the

vacuum breaker should be installed at the highest point in the system

where it will not be flooded with condensate.

��

Dp (mm Hg)

Example: 1 off Spirax Sarco VB21 vacuum breaker having 1⁄2"

screwed BSP connections.

��

How to order

VB14 and VB21 Vacuum Breakers

TI-P019-02 ST Issue 8