Skip to content
P.C. Engineering Corporation
Spirax Sarco HM34 Series Carbon Steel Inverted Bucket Steam Trap

Overview

The Spirax Sarco HM34 Series is a robust inverted bucket steam trap constructed from carbon steel, designed for reliable condensate removal in horizontal steam line installations. This steam trap operates effectively on saturated steam pressures up to 32 bar g, making it suitable for medium to high-pressure industrial steam systems.

The HM34 features an integral internal strainer as standard, protecting the valve mechanism from debris and reducing maintenance requirements. The inverted bucket mechanism provides positive, mechanical operation—steam keeps the bucket buoyant and the valve closed, while condensate causes the bucket to sink and open the valve for discharge. This design delivers excellent air venting capability and resistance to waterhammer.

Manufactured in compliance with the Pressure Equipment Directive 2014/68/EU, the HM34 Series is available with EN 10204 2.2 certification upon request. Multiple connection options including screwed BSP/NPT, socket weld, and flanged ends ensure compatibility with diverse piping configurations in process plants.

Key Features

  • Carbon steel construction — forged steel cover (½", ¾") and cast steel body for durability in demanding environments
  • Inverted bucket mechanism — reliable mechanical operation with excellent air handling
  • Built-in strainer — integral stainless steel strainer screen (ASTM A240 316L) protects internals
  • Wide pressure range — operates up to 32 bar g maximum differential pressure
  • Multiple orifice options — selectable orifice sizes (HM34/4 to HM34/12) to match condensate loads
  • Flexible connections — available in screwed BSP/NPT, socket weld Class 3000, and flanged PN40/Class 150/Class 300
  • Stainless steel internals — valve, seat, lever, and bucket in corrosion-resistant stainless steel

Specifications

ParameterValue
Body MaterialCast steel 1.0619 +N
Cover MaterialForged steel 1.0460 (½", ¾") / Cast steel 1.0619 +N (1")
Valve & Seat MaterialStainless steel AISI 440B
Bucket MaterialStainless steel BS 1449 304 S31
Sizes Available½", ¾", 1" (DN15, DN20, DN25)
Maximum Allowable Pressure (PMA)40 bar g @ 120°C
Maximum Operating Pressure (PMO)32 bar g (saturated steam)
Maximum Operating Temperature (TMO)300°C
Minimum Operating Temperature0°C
Maximum Differential Pressure (ΔPMX)4 bar to 32 bar (varies by orifice selection)
Connection TypesScrewed BSP/NPT, Socket weld BS 3799 Class 3000, Flanged EN 1092 PN40, Class 150, Class 300
Design StandardPressure Equipment Directive 2014/68/EU
Cold Hydraulic Test Pressure60 bar g
Weight (Screwed)2.6 kg (½") / 4.0 kg (¾") / 10.4 kg (1")

Applications

The Spirax Sarco HM34 inverted bucket steam trap is engineered for horizontal installations across a wide range of industrial applications:

- Process heating equipment — jacketed vessels, heat exchangers, evaporators - Steam distribution mains — drip leg drainage on steam headers - Unit heaters and air handling units — HVAC steam coils - Sterilizers and autoclaves — pharmaceutical and food processing equipment - Textile and paper industries — drying cylinders and calendering rolls - Chemical and petrochemical plants — process steam systems requiring carbon steel construction

Frequently Asked Questions

Get a Quote

Contact PC Engineering for pricing, availability, and technical support for the Spirax Sarco HM34 Series Carbon Steel Inverted Bucket Steam Trap. Call us or fill in our inquiry form — our engineers will respond within 24 hours.

Related Steam Traps

Spirax Sarco HM34 Series Carbon Steel Inverted Bucket