Submerged helium blowers


Howden has been supplying submerged blowers for almost 50 years, starting in the late 1950s with the United Kingdom Advanced Gas-cooled Reactor programme. These blowers are fully submerged in the process cooling gas, and thus overcome the twin problems of process contamination and maintenance associated with the use of running seals.

Our unique expertise and experience in submerged blowers started with the development of the submerged circulator concept. This was carried forward into the development of the Advanced Gas-cooled Reactor power stations in the UK, where we supplied upwards of one hundred 6MW circulators over a twenty year period. These circulators were designed for both horizontal and vertical arrangement. They operate submerged in CO2 at 4 bar pressure, with oil bath or pressure fed bearings, and gas flow control by variable inlet guide vanes. The later units including external pressurized lubricating oil system, were seismically qualified.

Motors and generators

Key Features

  • Submerged circulator development was carried forward into the 1990s when we developed a number of submerged blower designs for High Temperature Gas Reactors with helium gas as the primary heat transfer medium.
  • We also developed a non-nuclear niche market principally in the UK and Far East for submerged blowers in gas flow calibration loops. These blowers are generally running in air at around 70 bar pressure.


  • ​They are all operating successfully and now run with up to 12 years between maintenance outages. We continue to supply both strategic and routine spares and technical support for the minimum 30 year life of these circulators.
  • We now have the capability to design and supply a wide range of submerged blowers utilizing active magnetic bearings and fully submerged high speed electric drives, in combination with a range of aerodynamically efficient impellers with high running and tip speeds suitable for helium coolant.


  • ​Nuclear cooling

If you would like to submit an enquiry please get in touch.