SPIRAX SARCO · ISOLATION VALVES
Spirax Sarco BSA3T Bellows Sealed Stop Valve – Throttling Isolation Valve for Steam & Condensate
Spirax Sarco BSA3T bellows sealed stop valve for zero-emission isolation in steam, condensate & gas systems. ANSI 150/300, ½" to 8".
Overview
The Spirax Sarco BSA3T is a flanged, in-line bellows sealed isolation valve engineered for applications requiring zero fugitive emissions from the stem seal. The bellows construction eliminates the need for conventional packing adjustments, resulting in low maintenance operation across steam, condensate, gas, and other critical fluid systems.
The BSA3T features a throttling valve plug designed for precise flow regulation during valve opening. Once the desired flow rate is achieved, an integrated locking screw and stroke limiter maintain consistent operation. This "T" version is specifically intended for regulating duties where controlled throttling is essential.
Constructed with a cast steel body rated to ANSI Class 300 design conditions, the BSA3T delivers reliable performance in demanding industrial environments. The valve bellows are designed in accordance with MSS SP-117, and disc-to-seat shut-off conforms to API 598 no-leakage requirements.
Key Features
- Bellows sealed stem for zero fugitive emissions
- Throttling plug for precise flow control and regulation
- Locking screw and stroke limiter to maintain set flow rate
- Cast steel construction rated to ANSI Class 300
- Available in ANSI 150 and ANSI 300 flange connections
- Conforms to API 598 for leak-tight shut-off
- EN 10204 (3.1.B) certification available on request
- Optional gland flange assembly (½" to 4") and balancing disc (6" & 8")
Specifications
| Parameter | Value | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Model | BSA3T | ||||||||
| Sizes | ½" to 8" | ||||||||
| Connections | ANSI 150: ½" – 4"; ANSI 300: ½" – 8" | ||||||||
| Body Design | ANSI Class 300 | ||||||||
| Body Material | Cast Steel ASTM A 216 WCB | ||||||||
| Bonnet Material | Forged Steel ASTM A 105 (½"–3"); Cast Steel ASTM A 216 WCB (4"–8") | ||||||||
| Bellows Material | Stainless Steel DIN 17440 x 6CRNiTi1810 | ||||||||
| Disc & Stem Material | Stainless Steel AISI 420 | ||||||||
| Seat Material | Stainless Steel AISI 420 | ||||||||
| Stem Packing | Graphite | ||||||||
| Max Design Temperature | 797°F (425°C) | ||||||||
| Max Cold Hydraulic Test Pressure | 1116 psig | ||||||||
| Standards | MSS SP-117 (bellows design), API 598 (seat leakage) | ||||||||
| Size | ½" | ¾" | 1" | 1½" | 2" | 3" | 4" | 6" | 8" |
| Cv | 4.7 | 8.2 | 14 | 35 | 55 | 140 | 226 | 480 | 848 |
| Size | Face-to-Face (A) | Height (B) | Weight | ||||||
| ½" | 6.0" (152 mm) | 8.07" (205 mm) | 13.2 lb (6.0 kg) | ||||||
| ¾" | 7.0" (178 mm) | 8.07" (205 mm) | 15.4 lb (7.0 kg) | ||||||
| 1" | 8.0" (203 mm) | 8.54" (217 mm) | 20.0 lb (9.0 kg) | ||||||
| 1½" | 9.0" (229 mm) | 9.56" (243 mm) | 24.3 lb (11.0 kg) | ||||||
| 2" | 10.5" (267 mm) | 9.56" (243 mm) | 33.0 lb (15.0 kg) | ||||||
| 3" | 12.5" (317 mm) | 11.29" (287 mm) | 64.0 lb (29.0 kg) | ||||||
| 4" | 14.0" (356 mm) | 15.07" (383 mm) | 108.0 lb (49.0 kg) | ||||||
| 6" | 17.5" (445 mm) | 17.7" (450 mm) | 207.0 lb (94.0 kg) | ||||||
| 8" | 22.0" (559 mm) | 24.48" (622 mm) | 424.0 lb (193.0 kg) |
Applications
The BSA3T bellows sealed stop valve is suitable for industries and applications where emission-free operation and throttling control are critical:
- Steam distribution and condensate return systems - Chemical and petrochemical processing plants - Pharmaceutical manufacturing facilities - Refineries requiring fugitive emission control - Power generation steam circuits - Food and beverage processing (utility steam lines) - Any application with strict environmental compliance requirements
Frequently Asked Questions
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