Gestra BK27N is a thermostatic bimetallic steam trap with nominal sizes DN40 and DN50. It features a 16Mo3 body and a Duo stainless-steel bimetallic regulator, with nominal pressure ratings of PN40 and PN63, a maximum operating temperature of 450°C, and an integrated Y-strainer and check valve. The trap can be installed in any position on horizontal or vertical pipelines and is available with flanged, socket-weld, and butt-weld connections. It is designed for condensate discharge and automatic thermodynamic air venting in high-temperature, high-pressure steam systems, and is also suitable for specific potentially explosive atmospheres.
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BK27N Bimetallic Steam Trap | Gestra
Thermostatic bimetallic steam trap, DN40/DN50, PN40 or PN63, with built-in Y-strainer.
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Specifications
- Steam trap type
- Thermostatic bimetallic steam trap
- Regulating element
- Duo stainless-steel bimetallic regulator, externally adjustable
- Applicable media
- Steam and condensate
- Pressure-temperature ratings
- PN 40: 40.0 bar (20°C), 38.2 bar (200°C), 30.2 bar (300°C), 26.7 bar (400°C), 25.8 bar (450°C); PN 63: 63.0 bar (20°C), 60.2 bar (200°C), 47.6 bar (300°C), 42.0 bar (400°C), 40.6 bar (450°C)
- Maximum differential pressure
- PN 40: 40 bar; PN 63: 45 bar
- Maximum operating temperature
- 450°C
- Nominal pressure
- PN 40 / PN 63
- Nominal size
- DN40, DN50
- Connection types
- DIN EN flanges, socket-weld ends, butt-weld ends
- Flange standards
- DIN EN 1092-1 B1 PN 40, DIN EN 1092-1 B2 PN 63, ASME Class 400 RF
- Socket-weld connection standard
- DIN 3239-R5 / ASME B 16.11, Class 3000
- Butt-weld connection standard
- DIN 3239-2-R3
- Body material
- 16Mo3 (1.5415), approximately equivalent to ASTM A 182 F1
- Bonnet material
- 16Mo3 (1.5415)
- Body sealing material
- Graphite / CrNi
- Integrated functions
- Integrated Y-strainer and check valve
- Air-venting capacity
- Automatic air venting during startup and operation; suitable for thermodynamic air venting in steam systems
- Installation
- Suitable for horizontal and vertical pipelines; can be installed in any position
- PED compliance
- Compliant with PED 97/23/EC; suitable for Group 2 fluids
- Suitability for explosive atmospheres
- Suitable for use in potentially explosive areas 0, 1, 2, 20, 21, and 22; the equipment is not marked with an Ex designation
Application scenarios
Condensate drainage in high-temperature, high-pressure steam systems
For condensate discharge in high-temperature, high-pressure steam systems. The product has a maximum operating temperature of 450°C and nominal pressure ratings of PN40 or PN63, and is suitable for steam and condensate media.
Automatic air venting and condensate discharge in steam systems
For automatic air venting and condensate discharge during steam system startup and operation, including thermodynamic air venting in steam systems.
Steam trapping in potentially explosive areas
Suitable for steam trapping applications in potentially explosive areas 0, 1, 2, 20, 21, and 22. The product is not marked with an Ex designation; actual use must be confirmed according to the applicable area classification and equipment compliance requirements.
Installation & maintenance notes
Installation orientation and position
Install the product according to its permitted installation configuration. BK27N is suitable for horizontal or vertical pipelines and can be installed in any position.
FAQ
How does the Gestra BK27N bimetallic steam trap discharge condensate and provide automatic air venting?
The BK27N uses an externally adjustable Duo stainless-steel bimetallic regulator. During startup, the bimetallic elements remain flat, and the operating pressure fully opens the valve. As the condensate temperature rises, the bimetallic elements bend and move the multistage nozzle toward the closed position. When the temperature decreases, the bend is reduced and the valve reopens at the set opening temperature. The thermostatic and spring characteristics of the laminated bimetallic elements are balanced against each other, enabling condensate discharge at the specified subcooling temperature and automatic air venting during startup and operation.
What pressure, temperature, and nominal size ranges are available for the BK27N?
The BK27N is available in DN40 and DN50 nominal sizes, with nominal pressure ratings of PN40 or PN63 and a maximum operating temperature of 450°C. For the PN40 version, the maximum operating pressure is 40.0 bar at 20°C and 25.8 bar at 450°C, with a maximum differential pressure of 40 bar. For the PN63 version, the maximum operating pressure is 63.0 bar at 20°C and 40.6 bar at 450°C, with a maximum differential pressure of 45 bar. Selection should consider the steam pressure, backpressure, condensate discharge rate, installation location, and connection type.
Can the factory setting of the BK27N be adjusted to change the condensate subcooling?
The BK27N is factory-set by default for the discharge of condensate with virtually no waterlogging. If greater subcooling is required for the operating conditions, the setpoint can be adjusted externally after the steam trap has been installed and the system has been depressurized. This adjustment function is provided by the Duo stainless-steel bimetallic regulator.
What connection types are available for the BK27N, and are there any installation orientation restrictions?
The BK27N can be connected using DIN EN flanges, socket-weld ends, or butt-weld ends. Flanged connections include DIN EN 1092-1 Type B1 PN40, Type B2 PN63, and ASME Class 400 RF. The socket-weld ends comply with DIN 3239-R5 or ASME B16.11 Class 3000. The butt-weld ends comply with DIN 3239-2-R3. The design is suitable for horizontal or vertical piping and permits installation in any orientation.
What auxiliary functions are integrated into the BK27N, and is it suitable for use in explosive atmospheres?
The BK27N incorporates a Y-type strainer and an integrated check valve, providing internal protection against contaminant ingress and media backflow. The device complies with PED 97/23/EC and is suitable for Group 2 fluids. Since the device itself has no potential ignition source, it can be used in potentially explosive atmospheres in Zones 0, 1, 2, 20, 21, and 22; however, the device body does not carry an Ex marking.