Cast Iron
Armstrong 400 Series forged chrome-moly steel inverted bucket steam traps are designed for vertical installation with a choice of screwed, socketweld, or flanged connections. A unique leverage system multiplies the force provided by the bucket to open the valve against system pressure. The mechanism is free-floating and has no fixed pivots to create wear or friction.
Because the mechanism is located at the top of the trap, no dirt can collect on the orifice. Small particles of dirt are held in suspension until discharged by the full differential purging action when the bucket sinks, pulling the valve off the seat. The discharge orifice is surrounded by a water seal, preventing live steam loss. Automatic air venting is provided by a small vent hole in the bucket, ensuring continuous automatic air and CO2 venting at steam temperature. Inverted bucket traps drain continuously to prevent condensate backup and are highly resistant to water hammer.
Operation on Superheat
A normally operating bucket trap is filled with saturated steam and condensate. Superheated steam can enter only as fast as the steam inside can condense. As a result, the temperature of the trap is at (or slightly below) saturated steam temperature, regardless of the degree of superheat.
Recommendations for Superheat Service
- Don’t oversize the orifice; a restricted orifice may be advisable.
- Specify a burnished valve and seat and an extended inlet tube and check valve.
- Provide a drip leg of adequate diameter and length.
- Provide a generous length (2'-3' or 600-900 mm) of inlet piping, with the trap below the main.
- Don’t insulate the trap or the inlet piping.
Materials and Connections
- Body: ASTM A182 F22 Class 3 Forged Chrome-Moly Steel (Models 413 and 415 are also available with cast 316 stainless steel bodies and all stainless steel internals).
- Internals: All stainless steel — 304.
- Valve and Seat: Hardened chrome steel — 17-4PH or Titanium.
- Connections: Screwed (NPT and BSPT), Socketweld, Flanged (DIN or ANSI).
- Options: Stainless steel internal check valve (Add suffix "CV" to trap number).
Dimensions and Weights
| Model No. Screwed or SW | 413 | 415 | 416 |
|---|---|---|---|
| Model No. Flanged | 413-FW | 415-FW | 416-FW |
| Pipe Connections (in) | 1/2, 3/4, 1 | 1, 1-1/4, 1-1/2 | 1-1/2, 2 |
| Pipe Connections (mm) | 15, 20, 25 | 25, 32, 40 | 40, 50 |
| "A" Diameter (mm) | 219 | 273 | 317 |
| "B" Height, Scr/SW (mm) | 310 | 379 | 448 |
| "BB" Height, Flanged (mm) | 378 | 459 | 546 |
| "G" Body OD (mm) | 137 | 175 | 216 |
| "K" Outlet to Inlet (mm) | 36.5 | 44.4 | 54.0 |
| Number of Bolts | 8 | 9 | 12 |
| Weight Scr. or SW (kg) | 29.5 | 57.2 | 93.0 |
| Weight, Flanged (kg) | 31.8 | 59.9 | 95.7 |
Note: All dimensions and weights are approximate. Use certified print for exact dimensions.
Pressure-Temperature Rating
| Model No. | Max. Oper. Pressure, Sat. Steam | Max. Allowable Pressure at 371°C (700°F) | Max. Allowable Pressure at 427°C (800°F) | Max. Allowable Pressure at 454°C (850°F) | Max. Allowable Pressure at 482°C (900°F) |
|---|---|---|---|---|---|
| 413 | 69 bar (1000 psig) | 83 bar (1200 psig) | 83 bar (1200 psig) | 72 bar (1050 psig) | 54 bar (780 psig) |
| 415 | 69 bar (1000 psig) | 76 bar (1100 psig) | 76 bar (1100 psig) | 74.5 bar (1080 psig) | 66.5 bar (965 psig) |
| 416 | 69 bar (1000 psig) | 117 bar (1700 psig) | 117 bar (1700 psig) | 93 bar (1350 psig) | 68 bar (990 psig) |
Notes: Maximum operating pressure to be marked on nameplate will be determined by actual orifice used. Traps with flanges may have different pressure-temperature ratings depending on flange rating and type. Maximum back pressure is 99% of inlet pressure.
Capacities
Model 413 Capacity
Model 415 Capacity
Model 416 Capacity
Maintenance
WARNING
Equipment under pressure - Operating temperature > 100°C. Make sure the trap is cold and depressurized before handling!
Internals Maintenance:
- Remove the complete trap from the steam line.
- Unscrew bolts and nuts and lift the cap.
- Clean or replace the bucket or mechanism (valve and seat).
- The mechanism should be adjusted so that when correctly aligned, the lever can be moved sideways the same distance to the right as to the left. If the guide pin is not in the middle of the orifices, adjust by slightly hitting with a hammer.
- Replace the gasket.
- Put the cap back on the body and screw bolts and nuts.
Important Note: The type and material of bolts must not be changed.
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