Two-Port Single Seat
Spirax Sarco SB and SBRA range of two-port gunmetal valves are designed for use with SA control systems to provide a self-acting temperature control unit. These valves are robustly constructed with stainless steel internals and are suitable for a wide range of industrial heating and cooling applications.
Available types
- SB: Normally open, single seat valve.
- SBRA: Normally closed, single seat valve. Available with a bleed hole or optional fuse device for specific cooling system requirements.
Standards and Certification
These products fully comply with the requirements of the Pressure Equipment Directive (PED). Typical Test Reports are available from the manufacturer upon request at the time of order placement.
Operating Limits
| Body design conditions | PN25 |
|---|---|
| Maximum design pressure | 25 bar g @ 120°C (363 psi g @ 248°F) |
| Maximum design temperature | 232°C (450°F) |
| Minimum design temperature | -10°C (14°F) |
| Maximum operating temperature | 232°C (450°F) |
| Minimum operating temperature | 0°C (32°F) |
TIP
Standard temperature limits are 232°C. When a spacer is used, the maximum temperature can be increased to 260°C.
Maximum Differential Pressure Δp
| Size | SB | SBRA |
|---|---|---|
| DN15 (1/2") | 17.2 bar (250 psi) | 12.0 bar (174 psi) |
| DN20 (3/4") | 10.3 bar (150 psi) | 7.0 bar (102 psi) |
| DN25 (1") | 6.8 bar (99 psi) | 4.7 bar (68 psi) |
Kv Values
| Size | DN15 (1/2") | DN20 (3/4") | DN25 (1") |
|---|---|---|---|
| Kv | 2.58 | 3.86 | 6.80 |
For conversion: Cv (UK) = Kv x 0.963; Cv (US) = Kv x 1.156.
Materials
| No. | Part | Material | Standard |
|---|---|---|---|
| 1 | Body | Gunmetal | BS 1400 LG2 |
| 2 | Valve plug | Stainless steel | BS 970 431 S29 |
| 3 | Valve seat ring | Stainless steel | BS 970 431 S29 |
| 4 | Valve seat gasket | Copper | BS 2870 C102 |
| 5 | Return spring | Stainless steel | BS 2056 302 S26 |
| 6 | Stem | Brass | BS 2874 CZ 121 |
| 7 | Bonnet | Brass | BS 2872 CZ 122 |
| 8 | Bonnet gasket | Graphite | Reinforced exfoliated |
| 9 | Cap | Brass | BS 2872 CZ 122 |
Dimensions and Weights
(Approximate values in mm and kg)
| Size | A1 (SB) | A2 (SBRA) | B | C | D | E | Weight |
|---|---|---|---|---|---|---|---|
| DN15 | 79 | 79 | 101 | 66 | 50 | 95 | 1.0 |
| DN20 | 95 | 79 | 101 | 66 | 50 | 95 | 1.3 |
| DN25 | 105 | 79 | 101 | 66 | 50 | 95 | 1.5 |
Installation
INFO
The valve should be installed in a horizontal pipe run. The position of the actuator will depend on the specific type fitted. Ensure the system is cooled and isolated before maintenance.
Spare Parts
Available spares include the valve seat and stem assembly, and gasket sets. When ordering, always specify the valve size and type.
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