Forbes Marshall Thermodynamic Trap
Forbes Marshall FMTD64 Thermodynamic Steam Trap: High-Performance Mainline Drainage
The Forbes Marshall FMTD64 is an all-stainless-steel thermodynamic steam trap engineered for severe mainline steam drainage and header applications. Equipped with an integral stainless steel strainer, the FMTD64 protects internal seats from scale while delivering continuous, reliable condensate evacuation across a broad operating pressure range up to 42 bar(g).
Available with screwed (BSP/BSPT/NPT), socket weld, or flanged connections (FMTD64FL), this robust trap features an induction-hardened disc to resist severe water hammer and extreme thermal conditions.
Key Features & Design Advantages
- All-Stainless-Steel Build: Forged ASTM A743 Gr CA40 body provides maximum corrosion resistance and durability.
- Hardened Seating Surfaces: Disc and integral body seat are induction hardened to ~45 RC to withstand intense water hammer.
- Concentric Condensate Entry: Direct entry below the disc ensures a clean, parallel lift, eliminating localized seat wear.
- Integrated Strainer: Stainless steel mesh screen captures pipe debris to prevent valve jamming.
- Gasketless Threaded Design: Body caps seal without gaskets; require only high-temperature anti-seize grease during maintenance.
Technical Specifications & Operating Limits
|
Technical Parameter |
Specification Standard |
|
Available Sizes |
DN 15, DN 20, DN 25 (½", ¾", 1") |
|
End Connections |
Screwed (BSP/BSPT/NPT), Socket Weld (SW), Flanged (PN40, Class #150, Class #300) |
|
Max Operating Pressure (PMO) |
42 bar(g) (Recommended) |
|
Min Operating Differential Pressure |
0.25 bar(g) |
|
Max Allowable Temperature (TMA) |
400°C @ 42 bar(g) |
|
Maximum Back Pressure |
Up to 80% of inlet pressure |
|
Body Material |
Stainless Steel ASTM A743 Gr CA40 |
|
Disc Material |
Stainless Steel ASTM A240 SS 420 |
|
Strainer Screen |
Stainless Steel ASTM A240 Type 304 |
Maintenance & Refacing Guidelines
- Disassembly: Remove optional ISOTUB insulator cover and unscrew main cap using a spanner (avoid pipe wrenches to prevent distortion).
- Lapping Seats: Lightly worn disc and body seating faces can be restored using a figure-eight motion on a flat plate with a 1:6 diluted lapping compound (6-micron Aluminium Oxide).
- Grinding Limits: Total metal removal during regrinding and lapping must not exceed 0.25 mm (0.010 in).
- Reassembly: Insert disc with the grooved side facing the body seat. Apply Molybdenum Disulphide grease to strainer cap threads and high-temperature anti-seize compound to main body cap threads.
