All-Stainless Steel Material
Product Overview
The Spirax Sarco VB21 is a compact general-purpose vacuum breaker primarily used in condensing steam and liquid systems, effectively meeting system vacuum breaking requirements.
Quality Certification
Body and bonnet can be supplied with EN10204 2.2 certificates, ensuring product quality meets relevant standards.
Technical Specifications
Design Parameters
| Design Parameter | Value |
|---|---|
| Body Design Rating | PN25 |
| Maximum Allowable Pressure (PMA) | 25 bar g @ 120°C |
| Maximum Allowable Temperature (TMA) | 400°C @ 13 bar g |
| Minimum Allowable Temperature | -48°C |
| Maximum Saturated Steam Pressure (PMO) | 21 bar g |
| Maximum Operating Temperature (TMO) | 400°C @ 13 bar g |
| Minimum Operating Temperature | 0°C |
| Cold Hydraulic Test Pressure | 38 bar g |
| Opening Differential Pressure (Dp) | 4.6 mmHg |
Low Temperature Applications
For operating temperatures below 0°C, please contact Spirax Sarco for technical support.
Connection Parameters
| Connection Point | Size | Connection Type |
|---|---|---|
| System Connection | ½" | BSP or NPT threaded |
| Air Inlet Connection | 1/8" | BSP or NPT threaded |
Pressure/Temperature Limits
Dimensions and Weight
| Size | Dimension A (mm) | Dimension B (A/F, mm) | Dimension C (mm) | Kv Value | Weight (kg) |
|---|---|---|---|---|---|
| ½" | 52 | 36 | 36 | 0.52 | 0.33 |
Capacities
Materials of Construction
| No. | Component | Material | Specification |
|---|---|---|---|
| 1 | Cap | Stainless Steel | AISI 303 |
| 2 | Disc | Stainless Steel | AISI 440C |
| 4 | Body | Stainless Steel | AISI 303 |
| 5 | Gasket | Stainless Steel | AISI 304 |
Installation Instructions
Installation Requirements
- The VB21 vacuum breaker must be installed in a vertical position with the system connection at the bottom.
- When used in steam systems, the vent valve must be installed at the highest point of the system to prevent the valve from being submerged in condensate.
For detailed installation procedures, please refer to the Installation and Maintenance Instructions (IM-P019-05) supplied with the product.
Maintenance and Safety
For detailed maintenance procedures and safety precautions, please refer to the Installation and Maintenance Instructions (IM-P019-05) supplied with the product to ensure compliance and safety.
Ordering Information
Spirax Sarco ½" VB21 Vacuum Breaker with BSP threaded connection (other connection types available on request).
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