Automatic Drainage Valve type AK | Gestra

Automatic Drain Valve GESTRA AK 45

The GESTRA AK 45 is an automatic drain valve designed for steam lines during startup and shutdown. It remains open without pressure via an integrated spring and closes when the system pressure reaches the set closing pressure. The factory setting for closing is 0.8 bar differential pressure.

Technical Specifications

• Type: AK 45
• PN: 40
• DN: 15, 20, 25 / 1/2", 3/4", 1"
• Body Material: C22.8 / 1.0460, ASTM A105 equivalent
• Internal Parts: Stainless Steel
• Connections: Flanges DIN PN40, ANSI Class 150/300, BS 10 or BSP/NPT threads
• Operating Limits: up to 32 barg at 250°C, 22 barg at 385°C, 21 barg at 400°C
• Integrated Y-type Filter
• Manual Cleaning Button for Seat Deposit Removal

Operation in Steam Line

During startup, it removes air and cold condensate before the line reaches operating pressure. During shutdown, it reopens when pressure falls below the setpoint, draining residual liquid and reducing the risk of vacuum, frost, and water hammer.

Not a continuous operation steam trap. Typically installed alongside a steam trap in headers, low points, or startup lines.

Applications

• Steam headers and distributors
• Low pipeline points
• Outdoor lines at frost risk
• By-pass manual drainage
• Boiler house and process network startup

Installation and Selection

Prefer discharge to open drain without backpressure, in vertical line with downward flow. Horizontal installation requires 90° downward bend at outlet. Selection based on DN, connection type, closing pressure, line temperature, and material compatibility with medium.

FAQ

Is an actuator needed?
No. Operation is mechanical, via spring and differential pressure.

When is it used?
When automatic drainage is required during startup or after steam network shutdown.