Gestra UNA38 is a high-pressure ball float and needle valve steam trap with a 16Mo3 body and stainless steel internals. It withstands temperatures up to 530°C, is rated up to PN 100/Class 600, and is unaffected by back pressure. The product is available in DN15 to DN50 sizes, supports horizontal or vertical installation, and can be fitted with an optional DUPLEX control unit with automatic air venting. It is specifically designed for condensate discharge and drip drainage in high-pressure steam systems and high-temperature steam process lines.
Gestra UNA38 high-pressure steam trap product photo, three-quarter view
1 / 1
UNA38 Ball Float Steam Trap | Gestra
High-pressure steam trap with ball float and needle valve, PN100/Class 600, DN15 to DN50.
Genuine product assurance
We can help verify product data and purchasing details.
Model confirmation
Confirm model, connection and key options before ordering.
After-sales support
After-sales communication support is provided according to the order agreement.
Specifications
- Steam trap type
- Ball float and needle valve steam trap
- Media
- Steam and condensate
- Nominal size
- DN15, DN20, DN25, DN40, DN50
- Pressure rating
- PN 100 / ASME Class 600
- Maximum allowable pressure
- 100 barg (-10 to 20°C, PN 100 flange, socket-weld end, or butt-weld end; Class 600 flange: -10 to 100°C)
- Maximum allowable temperature
- 530°C (22.3 barg, PN 100 flange, socket-weld end, or butt-weld end)
- Maximum allowable differential pressure
- 50 bar (orifice 50); 64 bar (orifice 64); 80 bar (orifice 80 or 80 MAX)
- Orifice sizes
- 50, 64, 80, 80 MAX
- Orifice diameter
- 2.8 mm (orifice 50); 2.3 mm (orifice 64); 2.0 mm (orifice 80); 6.5 mm (orifice 80 MAX)
- Control unit
- SIMPLEX or DUPLEX
- Automatic air venting
- DUPLEX control unit with bimetallic air vent valve
- Back-pressure effect
- Unaffected by back pressure
- Body configuration
- Horizontal or vertical; interchangeable by repositioning the body and control unit
- Connection options
- EN 1092-1 B2 PN 100 flange, ASME B16.5 Class 600 RF flange, DIN EN 12760 socket-weld end, ASME B16.11 Class 3000 socket-weld end, butt-weld end via adapter
- Body material
- 16Mo3 (1.5415; approximately equivalent to ASTM A182-F1)
- Cover material
- 1.7357 (approximately equivalent to ASTM A217-WC6)
- Internals material
- Stainless steel
- Body gasket material
- Graphite/CrNi
- High-temperature version materials
- Flange or butt-weld end connections provided via an adapter made of 1.7335 (approximately equivalent to ASTM A182-F12)
- Pressure Equipment Directive
- PED applicable, Group 1 and Group 2 fluids
Application scenarios
Condensate discharge in high-pressure steam systems
UNA38 is used for condensate discharge in high-pressure steam systems. It is available in DN15 to DN50 sizes and can be connected using PN100 or ASME Class 600 flanges, socket-weld ends, or butt-weld ends.
Drip drainage in high-temperature steam process lines
UNA38 can be used for point condensate drainage in high-temperature steam process lines. It features a 16Mo3 body and stainless steel internals and supports operating conditions up to 530°C, subject to the rated pressure and temperature limits, with multiple flange and welded-end connection options.
Installation & maintenance notes
Match the installation orientation to the body configuration
Select a horizontal or vertical body configuration according to the site piping layout during installation. Ensure that the positioning relationship between the body and control unit complies with the installation requirements. The installation configuration can be changed by repositioning the body and control unit.
Observe the allowable pressure and temperature ranges
During installation, commissioning, and maintenance, ensure that operating conditions comply with the specified maximum allowable pressure, maximum allowable temperature, and maximum allowable differential pressure for UNA38. Do not exceed the product parameters.
FAQ
How does the UNA38 work?
The UNA38 uses a ball float control unit: as condensate enters the valve body, it lifts the float and opens the discharge passage, allowing the condensate to be discharged; once the discharge reaches the set flow rate, the float rises and closes the passage, maintaining a safe system pressure.
How is the UNA38 selected to match a high-pressure steam system?
The specific model is determined by the required end connection (DIN/ANSI flanges, socket-weld ends or butt-weld ends), the DN/PN rating, the operating differential pressure and the maximum permissible differential pressure.
Which end connections does the UNA38 support?
The UNA38 is available with a range of end connection options, including DIN/ANSI flanges, socket-weld ends and butt-weld ends, allowing compatible installation with existing pipework.
What types of control units are available for the UNA38, and what are their applications?
The SIMPLEX control unit is a level-dependent float controller suited to applications with relatively low condensate temperatures; the DUPLEX control unit is a float controller with a bimetallic air vent valve providing automatic temperature-dependent venting, suited to saturated and superheated steam.
What are the sealing and body materials of this steam trap, and what material information should be noted?
The body is made of structural steel 16Mo3 and the seat seal uses graphite/CrNi; for further material information, please confirm the specific part number and configuration with us when selecting the model.