SPIRAX SARCO · VACUUM BREAKERS
Spirax Sarco VB14 and VB21 Vacuum Breakers – Industrial Steam System Protection
Spirax Sarco VB14 & VB21 vacuum breakers for steam and liquid systems. PN16/PN25 rated, brass & SS construction. Available from PC Engineering India.
Overview
The Spirax Sarco VB14 and VB21 are purpose-designed vacuum breakers engineered for general-purpose applications in condensing vapour (steam) or liquid systems. These compact devices prevent vacuum formation in pipelines and equipment by allowing air ingress when system pressure drops below atmospheric levels.
The VB14 features brass body construction suited for standard industrial applications up to PN16, while the VB21 offers stainless steel construction for higher pressure ratings (PN25) and more demanding process conditions including elevated temperatures up to 400°C. Both models comply with the European Pressure Equipment Directive (PED) and are available with manufacturer's Typical Test Reports.
These vacuum breakers are essential for protecting heat exchangers, steam coils, storage tanks, and process vessels from collapse damage caused by condensation-induced vacuum conditions.
Key Features
- Purpose-designed for condensing steam and liquid system protection
- VB14: Brass body construction for cost-effective general applications
- VB21: Full stainless steel construction for corrosive environments and higher ratings
- Low differential pressure opening (4.6 mm Hg) for responsive vacuum relief
- Compact design with ½" screwed connections (BSP or NPT)
- PED compliant with certification available
- Simple vertical installation with minimal maintenance requirements
Specifications
| Parameter | VB14 | VB21 |
|---|---|---|
| Body Design Conditions | PN16 | PN25 |
| Max Allowable Pressure (PMA) | 16 bar g @ 180°C | 25 bar g @ 120°C |
| Max Allowable Temperature (TMA) | 260°C @ 7 bar g | 400°C @ 13 bar g |
| Max Operating Pressure – Steam (PMO) | 14 bar g | 21 bar g |
| Max Operating Temperature (TMO) | 260°C @ 7 bar g | 400°C @ 13 bar g |
| Min Operating Temperature | 0°C | 0°C |
| Min Allowable Temperature | -196°C | -48°C |
| Cold Hydraulic Test Pressure | 24 bar g | 38 bar g |
| ΔP to Open | 4.6 mm Hg | 4.6 mm Hg |
| Body Material | Brass (CuZn39Pb3) | Stainless Steel AISI 303 |
| Valve Material | SS Z100CD17 | SS AISI 440C |
| Connection Size | ½" BSP/NPT | ½" BSP/NPT |
| Kv Value | 0.52 | 0.52 |
| Dimensions (A × B × C) | 55 × 34 × 34 mm | 52 × 36 × 36 mm |
| Weight | 0.35 kg | 0.33 kg |
Applications
- Steam heating systems and heat exchangers - Process vessels and storage tanks subject to condensation - Jacketed reactors and autoclaves - Sterilizers and steam coils - Cooling systems where vacuum conditions may develop - Any closed system where condensing vapours can create sub-atmospheric pressure
Frequently Asked Questions
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