The Gestra BK37 is a steam trap based on the Thermovit® bimetallic element thermostatic/thermodynamic operating principle, designed for steam and condensate systems. The product has a nominal pressure rating of up to PN 63. Its body is made of 1.5415 structural steel and is equipped with a wear-resistant titanium alloy seat and an integrated strainer. It offers excellent water hammer resistance, can be installed in any position, and provides automatic thermodynamic air venting during start-up and operation. The BK37 is widely suitable for condensate drainage from steam pipelines and main steam lines, as well as automatic air venting in high-temperature, high-pressure steam systems.
Gestra BK37 bimetallic steam trap, oblique product view
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BK37 Bimetallic Steam Trap | Gestra
Thermostatic/thermodynamic bimetallic steam trap for condensate discharge and automatic air venting in steam lines; available with flanged, butt-weld and socket-weld connections.
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Specifications
- Operating principle
- Thermovit® bimetallic element thermostatic/thermodynamic type
- Service media
- Steam and condensate
- Nominal pressure
- PN 63
- Maximum allowable differential pressure
- 45 barg
- Allowable operating pressure-temperature rating
- Flanged end: 100 barg at 20–150°C, 94 barg at 265°C, 80.9 barg at 350°C, 73 barg at 415°C, 44.2 barg at 500°C; butt-weld/socket-weld end: 100 barg at 20–400°C, 85 barg at 470°C, 61 barg at 500°C, 30.9 barg at 530°C
- Maximum allowable operating temperature
- Flanged end: 500°C; butt-weld/socket-weld end: 530°C
- Connection type
- DIN flange, socket-weld end, butt-weld end
- Connection standards
- Flange: EN 1092-1 PN 63; butt-weld end: DIN EN 12627; socket-weld end: DIN EN 12760
- Connection sizes
- DN15, DN20, DN25
- Body material
- Structural steel 1.5415
- Sealing material
- Graphite/CrNi
- Seat material
- Wear-resistant titanium alloy
- Temperature sensor material
- Corrosion-resistant Duo S. S.
- Integrated strainer
- Yes
- Check function
- Integrated check function
- Installation position
- Can be installed in any position
- Air venting function
- Automatic air venting during start-up and operation; suitable for thermodynamic air venting
- Water hammer resistance
- Resistant to water hammer
- ATEX applicable zones
- Ex zones 0, 1, 2, 20, 21, 22; equipment is not marked Ex
Application scenarios
Condensate drainage from steam pipelines and main steam lines
For condensate drainage from steam pipelines, main steam lines or branch lines. The BK37 is suitable for steam and condensate media, has a nominal pressure rating of PN 63, provides water hammer resistance, and can be connected using flanged, socket-weld or butt-weld ends.
Automatic air venting during steam system start-up and operation
For automatic air venting and condensate drainage during steam system start-up and operation. The BK37 provides automatic air venting during start-up and operation and can be used for thermodynamic air venting, making it suitable for high-temperature, high-pressure steam systems.
Installation & maintenance notes
Media, temperature and differential pressure limits
During installation, commissioning and operation, verify that the media is steam or condensate and ensure that the operating temperature, operating pressure and differential pressure remain within the allowable range for the corresponding BK37 connection type and model. Operation beyond these limits may result in leakage or equipment damage.
Maintenance inspection of the integrated strainer
During maintenance and inspection, check and clean the integrated strainer to prevent pipeline debris from affecting the normal closing and operation of the steam trap, which could cause leakage or reduced performance.
FAQ
How does the BK37 operate, and at what point does it achieve rapid discharge?
The BK37 works on a thermostatic/thermodynamic discharge principle with a bimetallic Thermovit® regulator. At plant start-up the valve opens fully to discharge condensate and air; as the temperature rises, the bimetallic discs bend and close the nozzle, combining effective drainage with protection against steam loss.
What are the key selection differences between the BK37 and the BK28/BK29?
The BK37 series is rated PN63 with flanged connections, while the BK28/BK29 are offered in combinations with higher pressure ratings. The BK28/BK29 are suitable for applications involving higher back pressure; PN/CL ratings and end connections vary by model, and the specific configuration must be confirmed against the actual pipeline conditions.
Which end connection options are available for this steam trap, and how should they be selected?
Three connection types are available: DIN flanges, socket-weld ends and butt-weld ends. The choice should match the design standard and pressure rating of the system piping; the specific end connection, together with the corresponding end size and weight for each model, is given in the model table.
Can the BK37 also provide air venting in a steam system?
Yes. The BK37 and other valves in the series automatically vent air during plant start-up and operation, and can also be used for thermal air venting, improving gas removal efficiency in both the initial phase and normal operation of the system.