Calder vacuum units are designed for use in hazardous environments for operation in accordance with ATEX, NORSOK, IECEx and other standards. These offshore vacuum units utilise positive displacement or liquid ring technologies to provide vacuum performance with pressures up to 810 mbar and flows up to 50m³/min.

MultiVac units are used by customers for a variety of vacuum applications including: waste transfer, chemical/liquid recovery, bulk powder removal, ventilation, and pigging, descaling and de-sanding operations.

The MultiVac can be diesel engine or electric motor driven, and there is a range of pressures, flows, and control options. Whether crash frame mounted for weight minimization, or container mounted for maximum protection and noise attenuation, our range of standard vacuum units and our bespoke design capabilities ensure we can provide the right vacuum unit for your offshore, hazardous area requirements.

The MultiVac unit follows the same principles of quality, reliability, safety, ease of operation and ease of maintenance as our successful range of MultiJet high pressure water jetting machines.

To speak directly with one of our sales engineers, call +44 1905 751790 or email

  • Vortex separator for solids removal.
  • Solids tank capacity 1.7 m³.
  • Removal waste tray.
  • Waste tray capacity 1.0 m³.
  • Pump impeller oil dosing system.
  • Electric or pneumatic control system and shutdowns.
  • External access to fuel fill, services manifold, and the control panel.
  • Gas and fire detection.
  • Fire suppression systems.
  • Noise attenuation – Various options to reduce noise levels.
  • High ambient temperature operation for environments up to 50°C.
  • Maintenance lifting points – Located above internal components to enable fitting of chain hoist to assist with equipment removal/maintenance.
  • Internal hazardous area lighting.

Material/waste removal:

  • of coatings from surface preparation.
  • from tanks, vessels, mud pits and silos.
  • from hazardous drainage systems.
  • of viscous, dense materials.
  • from confined spaces.

  • Chemical, fuel, and liquid recovery from open/bunded areas.
  • Transfer of waste from open top skips to closed skips.
  • Bulk powder removal.
  • High flow ventilation of hazardous atmospheres.
  • Hydrocarbon heavy waste removal while atmospheric venting.
  • Pigging support operations – prevention of uncontrolled release of hydrocarbon materials.
  • Descaling support – control of water discharge.
  • Online/offline de-sanding operations.