Howden Dresser Universal RAI (URAI) blowers are heavy duty positive displacement rotary blowers developed with detachable rugged steel mounting feet. The detachable mounting feet design provides flexible custom installation for both vertical or horizontal installation requirements and make these products easily adaptable to any one of four drive shaft positions (top, bottom, left or right hand).

Need help sizing your blower? The HR Blower engineering team are here to assist. Contact us today.

Howden Roots Universal RAI Blower (URAI)
Universal RAI Blower

Heavy duty, bi-lobe rotary blowers in a compact & sturdy design, engineered for continuous running with exceptional reliability.

  • Cost effective design.
  • Pressures to 15 psig (1034 mbar).
  • Vacuums to 16” Hg (539 mbar).
  • Flows to 2370 cfm (4026 m3/hr).
  • Available with metric drive shaft.
  • Range of Roots URAI blower frame sizes available.

Howden Universal RAI-J DSL Blower


DSL features are incorporated into the Universal RAI-J model for long life and quiet performance.

  • All the Universal RAI (URAI) family of blowers feature detachable feet, allowing you to mount the blower into your custom system.
  • Range of Roots URAI J DSL blower frame sizes available.

Dresser Howden Universal RAI DSL Blower


  • Available with metric drive shaft and pipe connections.
  • Range of Roots URAI DSL blower frame sizes available.
  • This model features Dual Splash Lubrication (DSL) on both the gear end and drive end. Dual splash lube provides:
  • More oil capacity.
  • Cooler operation.
  • Greater reliability.

Howden Roots SRB and SRE packages


Each standard packaged blower combines a ROOTS blower unit supplying oil-free air with an electric motor, vee-belt drive, intake filter/silencer, filter restriction indicator, discharge silencer, non-return valves & relief valves. The blower is mounted on a rigid baseplate and contained within a practical acoustic enclosure, which silences the machine to 75-80 dbA when measured under free-field conditions.

  • The SRB range covers pressures from 300 to 1000 mbar (1.5-15kW) with inlet volumes from 50m³/h.

  • The SRE range covers 300 mbar to 500 mbar (1.5kW to 7.5kW).

  • Pressure relief and non-return valves are supplied loose for installation into customer’s pipework.

  • The packages have hinged access with security locks.

Howden Universal RAI-J Blower

URAI-J Blower

Incorporates Roots WHISPAIR* technology to reduce noise levels 3-5 dBA.

  • Range of Roots URAI J blower frame sizes available.

Howden Dresser Universal RAI-G Blower

This model features mechanical seals that virtually eliminate leakage.

  • 1/8” (0.3137 cm) NPT purge port for buffer gas applications.
  • Range of Roots URAI G blower frame sizes available.

Why choose HR Blowers for your Universal RAI Blower needs?

  • Many units already in stock.
  • Quick delivery turnaround.
  • Worldwide delivery available.
  • All stock comes with a warranty.

HR Blowers also can supply a range of Roots URAI blower parts from across a range of manufacturers and can also help you with your installation and Universal RAI blower servicing needs.