Spirax Sarco BSA/BSAT are flanged bellows-sealed globe valves featuring double-layer stainless steel bellows and graphite stem packing, suitable for steam, gases, liquids, condensate, and water. BSA is fitted with a balanced plug for shut-off isolation, while BSAT is equipped with a throttling plug and stem locking device, making it suitable for isolation or manual control in steam mains, drainage, and condensate recovery piping.
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Spirax Sarco BSA/BSAT Bellows-Sealed Globe Valves (Flanged Connection)
Bellows-sealed globe valves for steam and condensate isolation, with optional throttling plug.
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Models
BSA and BSAT are Spirax Sarco flanged double-bellows sealed globe valves for steam, gas, liquid, condensate, water, and other media. BSA uses a flat disc and is primarily intended for pipeline shut-off and isolation. BSAT uses a throttling disc with a stem locking device, making it suitable for applications requiring manual throttling and maintenance of a set opening. Select the model according to whether throttling and locking functions are required, then verify the applicable size, pressure rating, temperature, body material, seat type, and allowable differential pressure for the specific variant.
BSABSA Bellows-Sealed Flat-Disc Globe Valve
BSA is a flanged double-bellows sealed globe valve with a flat disc, suitable for steam, gas, liquid, condensate, water, and other media. It is primarily used for pipeline shut-off and isolation. The series is available in multiple connection pressure ratings and sizes; specific configurations are subject to model, material, and connection rating limitations.
BSATBSAT Bellows-Sealed Throttling-Disc Globe Valve
BSAT is a flanged double-bellows sealed globe valve with a throttling disc and stem locking device, suitable for steam, gas, liquid, condensate, water, and other media. It can be used in applications requiring manual throttling. Its throttling service is subject to the maximum allowable differential pressure for the applicable size. Model, material, connection rating, temperature, and seat type must also be verified for the specific configuration.
Specifications
- Valve Type
- Bellows-sealed globe valve with double bellows seal
- Applicable Media
- Steam, gas, liquids, condensate, and water
- Connection Type
- Flanged connection
- Connection Pressure Ratings
- PN16, PN25, PN40, ANSI 150, ANSI 300, KS 20
- Connection Sizes
- DN15, DN20, DN25, DN32, DN40, DN50, DN65, DN80, DN100, DN125, DN150, DN200, DN250; available sizes are subject to model, material, and connection rating restrictions
- Plug Type
- BSA with flat plug; BSAT with throttling plug and stem locking device; balanced plug optional
- Seat Type
- Metal seat; optional R-PTFE soft seat (25% carbon-filled)
- Body Materials
- BSA2/BSA2T: ductile iron EN-GJS-400-18-LT; BSA3/BSA3T: cast steel 1.0619 or ASTM A216 WCB; BSA6T: stainless steel EN 10213 1.4408 or ASTM A351 CF8M
- Key Sealing Materials
- Bellows: stainless steel; stem packing: graphite; soft-seat insert: R-PTFE, 25% carbon-filled
- Leakage Class
- Plug-to-seat sealing complies with EN 12266-1 Class A and ISO 5208 Class A; BSA3 ANSI complies with API 598 zero leakage
- Maximum Allowable Pressure
- BSA2/BSA2T: 16 barg for PN16, 25 barg for PN25; BSA3T: 40 barg for PN40; BSA3/BSA3T: 19.6 barg for ASME 150, 51 barg for ASME 300, 34 barg for JIS/KS 20K; BSA6T: 40 barg @ 50°C
- Maximum Working Pressure for Saturated Steam
- BSA2/BSA2T: 14.7 barg for PN16, 22.3 barg for PN25; BSA3T PN40: 30.4 barg; BSA3/BSA3T: 14 barg for ASME 150, 41.6 barg for ASME 300, 30.7 barg for JIS/KS 20K; BSA6T with metal seat: 29.8 barg @ 236°C, with soft seat: 27.0 barg @ 230°C
- Maximum Operating Temperature
- BSA2/BSA2T: metal seat 350°C, soft seat 230°C; BSA3T: metal seat 400°C, soft seat 230°C; BSA3/BSA3T: metal seat 425°C, soft seat 230°C; BSA6T: metal seat 400°C @ 25.6 barg, soft seat 230°C @ 27.0 barg
- Minimum Operating Temperature
- BSA2/BSA2T, BSA3T, and BSA6T: -10°C; BSA3/BSA3T ANSI: -29°C; BSA3/BSA3T JIS/KS 20K: 0°C
- Maximum Allowable Differential Pressure for Throttling
- 2.0 bar for DN15-DN80; 1.5 bar for DN100-DN125; 1.0 bar for DN150; 0.8 bar for DN200-DN250
- Rated Kv Values
- DN15: 4, DN20: 7, DN25: 12, DN32: 19, DN40: 30, DN50: 47, DN65: 77, DN80: 120, DN100: 193, DN125: 288, DN150: 410, DN200: 725, DN250: 1145
- Available Certificates
- EN 10204 3.1 certificates are available for BSA2, BSA2T, BSA3, BSA3T, and BSA6T
- Compliant Standard
- European Pressure Equipment Directive 97/23/EC
Application scenarios
Steam Main and Steam-Using Equipment Isolation
Used for shut-off and maintenance isolation on steam mains, branch lines, or piping to steam-using equipment. Designed for steam systems with a double stainless steel bellows seal; the BSA flat plug is suitable for applications primarily requiring shut-off.
Condensate Recovery and Steam Trap Isolation
Used for isolation in condensate branch lines, recovery piping, and steam trap-related pipelines. Product documentation specifies suitability for condensate and water systems, while the double bellows seal helps reduce the risk of external leakage at the stem.
Manual Throttling of Steam or Process Lines
The BSAT type can be used for manual flow control in steam, gas, liquid, water, or condensate pipelines, with the stem locking device maintaining the set opening. Throttling applications must meet the maximum allowable differential pressure requirements for the applicable valve size.
Selection points
Double Bellows and Graphite Packing Seal Design
This series uses a double stainless steel bellows seal with graphite stem packing, suitable for external leakage control in steam, gas, liquid, condensate, water, and other media applications.
BSA and BSAT Disc Function Variants
BSA uses a flat disc, while BSAT uses a throttling disc with a stem locking device. Select the model according to shut-off isolation or throttling position-locking requirements.
Multiple Body Materials for Different Models
The series is available with ductile iron, cast steel, and stainless steel valve bodies: BSA2/BSA2T in ductile iron, BSA3/BSA3T in cast steel, and BSA6T in stainless steel. Select according to the specific model and connection pressure rating.
Different Temperature Limits for Metal and R-PTFE Soft Seats
The product is available with a metal seat or a 25% carbon-filled R-PTFE soft seat. For BSA3/BSA3T, the maximum operating temperature is 425°C for the metal seat and 230°C for the soft seat. Select according to operating temperature.
Throttling Service Is Subject to Size-Related Differential Pressure Limits
When BSAT is used for throttling, the maximum allowable differential pressure decreases as nominal size increases: 2.0 bar for DN15-DN80, 1.5 bar for DN100-DN125, 1.0 bar for DN150, and 0.8 bar for DN200-DN250.
Installation & maintenance notes
Differential Pressure Limits for BSAT Throttling Service
BSAT is fitted with a throttling disc. When used for throttling, the actual operating differential pressure must not exceed the maximum allowable value for the corresponding size: 2.0 bar for DN15-DN80, 1.5 bar for DN100-DN125, 1.0 bar for DN150, and 0.8 bar for DN200-DN250.
Verification of R-PTFE Soft Seat Temperature Limit
If the R-PTFE soft seat configuration is selected, verify site operating conditions before installation. The maximum operating temperature must not exceed 230°C.
FAQ
What is the operating principle of a bellows-sealed globe valve?
The valve uses a bellows seal to isolate the sealing chamber from the process medium. The plug moves relative to the seat to open or close the flow path. The BSAT series integrates a throttling plug and stem locking device, while the BSA series offers a flat plug option. The specific configuration must be confirmed based on the actual model.
What should be considered when selecting between the BSAT and BSA series?
The BSAT series features a throttling plug and stem locking device, making it suitable for applications requiring throttling control. The BSA series offers a flat plug for applications with different flow characteristic requirements. Selection should consider size, connection type, material, pressure rating, and whether soft-seat or metal-seat options are required. The specific configuration must be confirmed based on the actual model and application conditions.
What do the valve leakage class and Kv value mean?
Plug-to-seat sealing complies with EN 12266-1 Class A and ISO 5208 Class A; the BSA3(ANSI) leakage class complies with API 598 zero leakage. Kv values vary by valve size and are used for flow estimation. The appropriate coefficient is required to convert Kv to Cv. Specific Kv values depend on the model; refer to the flow data for the relevant model. The specific configuration must be confirmed based on the actual model and application conditions.
What are the application ranges of this valve in steam, gas, liquid, or condensate systems?
Bellows-sealed globe valves are designed for steam, gas, liquid, condensate, and water systems. The BSAT series offers a throttling plug option, while the BSA series offers a flat plug option. Actual suitability must be confirmed based on the medium, temperature, pressure, flanged connection, and differential pressure conditions.
What points should be noted during installation and maintenance?
Follow the installation and maintenance instructions supplied with the valve. Install according to the flow-direction arrow on the valve body and ensure that the handwheel is in an appropriate position. The valve can be reused, and suitable spare-part kits should be selected for maintenance; the specific spare-part scope depends on the model. The specific configuration must be confirmed based on the actual model and application conditions.