Continuous Blowdown Valve | Gestra

GESTRA Surface Blowdown Valve

The GESTRA continuous surface blowdown valve is installed on the surface blowdown line of steam boilers to control TDS (Total Dissolved Solids) and conductivity levels. Continuous evaporation increases dissolved solids in boiler water; if not removed, this leads to scale formation and increases the risk of carry-over into the steam network.

Variants

• BA 46 / BA 47: Manual flow adjustment via lever and calibrated scale.
• BAE 46 / BAE 47: Electrically actuated for automatic blowdown control based on conductivity.
• BA 46 / BAE 46: PN 40, DN 15–50.
• BA 47 / BAE 47: PN 63, DN 25, 40, 50.

Operation and Control

Blowdown flow is calculated based on steam output, feedwater conductivity, and the permissible boiler conductivity limit. BAE versions integrate with LRR conductivity controllers and LRG/LRGT electrodes or transmitters, enabling valve position to modulate according to real-time boiler water conductivity.

Technical Selection Criteria

• Connections: Flanges EN 1092-1 or ASME B16.5; welded ends available.
• Body material: 1.0460 / ASTM SA105.
• Stem sealing: PTFE yarn.
• Seat and step rings: 1.4104.
• Regulating needle: 1.4021.
• BAE actuator: 230 V, IP65; options for 24 V DC, 120 V, IP67, feedback potentiometer or 4–20 mA.

Operating Conditions

For BA/BAE 46 (PN 40): 40 bar at 20°C, 37.1 bar at 100°C, 33.3 bar at 200°C, 27.6 bar at 300°C. For BA/BAE 47 (PN 63): 63 bar, 58.5 bar, 52.5 bar, and 43.5 bar at respective temperatures.

Standards and Compliance

Applicable for EN 12952 and EN 12953 boiler systems. Equipment complies with PED for Group 2 fluids. Manual BA 46/47: CE Ex II 2G/D c X classification. Electrically actuated BAE versions are not suitable for explosive atmospheres unless specified.