High-pressure steam traps are essential in power plants, HP steam distribution, and refinery process units where operating pressures exceed 40 bar. These traps must withstand extreme temperatures, pressure cycling, and often superheated steam conditions while reliably draining condensate.
AQ Process Systems sources and exports forged steel high-pressure traps rated to 175 bar (Class 2500) in carbon steel, alloy steel (chrome-moly), and stainless steel. Available with socket-weld and butt-weld end connections, threaded connections are not recommended above 40 bar.
For HP steam applications, we can advise on the best trap type, thermodynamic for simplicity and compact size, inverted bucket for robust mechanical operation, or bimetallic for adjustable subcooling and high-pressure tolerance.
| Product | Specification | Description |
|---|---|---|
| HP Thermodynamic | ||
| HP Thermodynamic Traps | 1/2", 1" | PN up to 120 bar | Forged CS or alloy | High-pressure thermodynamic disc traps, compact, no adjustment, handles superheated steam. Preferred for HP steam mains and drip legs. |
| HP Inverted Bucket | ||
| HP Inverted Bucket Traps | 1/2", 1" | PN up to 175 bar | Forged steel | High-pressure inverted bucket traps, robust mechanical operation for HP steam mains and process equipment drainage. |
| HP Bimetallic | ||
| HP Bimetallic Traps | 1/2", 1" | PN up to 170 bar | Adjustable subcooling | High-pressure bimetallic traps with adjustable discharge temperature, for HP steam systems where subcooled discharge is beneficial. |
| HP Accessories | ||
| HP Trap Stations | Forged manifold | Isolation + trap + check | Pre-assembled high-pressure trap station manifolds with isolation valves, strainer, and check valve, forged construction. |
| HP Sight Glasses & Test Points | Forged body | SW or BW | Up to 175 bar | High-pressure sight glasses and test connections for monitoring HP trap discharge and performance verification. |
All three main types work at high pressure: thermodynamic (simplest, compact, handles superheat, up to 120 bar), inverted bucket (most robust, handles water hammer, up to 175 bar), and bimetallic (adjustable subcooling, up to 170 bar). Selection depends on the specific application, drip legs favour thermodynamic, process equipment drainage favours inverted bucket, and superheater drains often use bimetallic.
At high pressures (>40 bar), cast bodies have insufficient strength and integrity for the wall thickness required. Forged steel provides superior grain structure, consistent material properties, and higher allowable stress, essential for safe, reliable operation at Class 600-2500 pressures. Forged bodies also eliminate casting defects (porosity, inclusions) that could lead to failure.
Socket-weld (SW) is standard for sizes up to 2" at high pressure. Butt-weld (BW) is used for the highest pressures and critical applications. Threaded connections are not recommended above 40 bar due to the risk of thread leakage under thermal cycling. All welds should be per ASME B31.1 for power piping.
Thermodynamic traps handle superheated steam well, the disc operates on pressure differential, not temperature. Bimetallic traps also handle superheat as they respond to temperature. Inverted bucket traps may need superheat modification (larger vent hole) to prevent steam locking. All HP traps should have hardened internals for superheat service.
HP traps are hydrostatically tested to 1.5x the rated pressure per ASME/API requirements. Seat leakage testing per API 598 or BS EN 12266 verifies shutoff integrity. Material certification (EN 10204 3.1) traces the forging material to the original heat. All test certificates are supplied with the trap.
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