Inverted Bucket Steam Trap - 521 Series | Armstrong | Americas

Inverted Bucket Steam Trap – 521 Series

Inverted Bucket Steam Trap – 521 Series

Product Specifications

Model 521
Maximum Capacity 1300 lb/hr
(535 kg/hr)
Maximum Allowable Pressure 1000 psig
(69 barg)
Maximum Allowable Temperature 700°F
Body Material ASTM A105N
Forged Steel
Maximum Operating Pressure 1000 psig
(69 barg)
Connection Type Screwed
Connection Size 1/2″ (15 mm)
3/4″ (20 mm)
Flow Direction Horizontal

Inverted Bucket Steam Trap – 521 Series

521 Series Inverted Bucket Steam Traps in forged carbon steel, for horizontal installation offer smaller capacities at higher pressures.

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. Inverted bucket traps drain continuously to prevent condensate backup. They are also resistant to water hammer. Series 521 adds the convenience and savings of in-line repairability and is designed to meet today’s energy-management requirements efficiently and economically over a long, trouble-free service life. Series 521 have integral strainer to protect from dirt and scale.


  • CRN
  • EIL
  • IBR
  • NIBR