Description
Product Overview
The Spirax Sarco VB14 is a small, purpose-designed vacuum breaker manufactured in brass. It is utilized in condensing vapor and liquid systems to protect steam plant and process equipment against vacuum formation, while allowing condensate to drain effectively from pipework and storage vessels.
Key Features
- Manufactured with a brass body and cap, and a precision-ground stainless steel valve and seat to ensure a tight shut-off.
- Requires a differential pressure of 4.6 mm Hg (0.2 in Hg) to open.
- Provides a flow coefficient (Kv) of 0.52.
- Shut-off conforms to EN 12266-1 Rate E.
- Available with an EN 10204 2.2 Typical Test Report.
- Non-maintainable design requiring complete unit replacement upon failure.
Technical Specifications
Materials
| No. | Part | Material | Standard |
|---|---|---|---|
| 1 | Cap | Brass | Cu Zn 39 Pb3 |
| 2 | Valve | Stainless steel | Z 100 CD 17 |
| 3 | Valve seat | Stainless steel | Z15 CN 16 02 |
| 4 | Body | Brass | Cu Zn 39 Pb3 |
| 5 | Gasket | Stainless steel | AISI 304 |
Pressure and Temperature Limits
| Parameter | Description | Value |
|---|---|---|
| Body design conditions | PN16 | |
| PMA | Maximum allowable pressure | 16 bar g @ 180 °C (232 psi g @ 356 °F) |
| TMA | Maximum allowable temperature | 260 °C @ 7 bar g (500 °F @ 102 psi g) |
| Minimum allowable temperature | -196 °C (-321 °F) | |
| PMO | Maximum operating pressure for saturated steam service | 14 bar g (203 psi g) |
| TMO | Maximum operating temperature | 260 °C @ 7 bar g (500 °F @ 102 psi g) |
| Minimum operating temperature | 0 °C (32 °F) | |
| Designed for a maximum cold hydraulic test pressure of | 24 bar g (348 psi g) |
Capacity
Sizes, Connections, and Dimensions
- System connection: 1/2” screwed BSP or NPT.
- Air inlet connection: 1/8” screwed BSP or NPT.
| Size | A | B (A/F) | C | Kv | Weight |
|---|---|---|---|---|---|
| 1/2” | 55 mm (2.2”) | 34 mm (1.3”) | 34 mm (1.3”) | 0.52 | 0.35 kg (0.77 lbs) |
Applications
- General purpose applications on condensing vapor (steam) systems.
- Liquid systems requiring vacuum protection.
- Pipework and storage vessels requiring effective condensate drainage.
Installation and Operation
The VB14 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.
During normal operation, the precision-ground stainless steel valve is held firmly on its seat, ensuring a tight shut-off. During cooling, steam begins to condense resulting in a reduction of pressure. The valve remains on its upper seat until the pressure in the upper chamber falls below the air inlet pressure. At the point of vacuum, the valve will instantly lift off its seat, drawing air in through the upper chamber to prevent a vacuum from forming.