Stokes Microvac 412J

The Stokes Microvac rotary piston pump sets the standard for performance and reliability as the industries most efficient, space-saving design. The Stokes Microvac rotary piston pump has been improved, upgraded, and fine-tuned to deliver even better dependability and productivity combined with minimal maintenance and process downtime.

Features and Benefits

  • Robust cast and ductile iron construction provides rugged reliable operation.
  • Efficient design provides maximum uptime with minimal moving parts and large clearance.
  • Low ultimate blank-off with pressures down to < 10-2 Torr.
  • New valve design virtually eliminates valve maintenance and noise.
  • Space saving design which saves up to 50 of valuable floor space.
  • Complete and self-contained unit delivered ready to install.
  • Automatic lubrication system provides proper flow of oil to bearings and sealing surfaces and prevents back flow into system.
  • Controlled balancing reduces vibration to a practical minimum.
  • Gas ballast as standard.


  • Automotive
  • Chemical processing
  • General applications
  • Heat treatment
  • Leak detection
  • Metallurgy
  • PET processing
  • Pharmaceuticals
  • Transformer drying and cable fluid conditioning
  • Vacuum coating
  • Vacuum melting
Technical data  
Displacement (swept volume)(AVS) 510 m3h-1 / 300 ft3min-1
Pumping Speed 442 m3h-1 / 260 ft3min-1
Ultimate vacuum (total pressure)  
  without gas ballast <3.3x10-2 mbar / <2.5x10-2 Torr
  with gas ballast <2.6x10-1 mbar / <2x10-1 Torr
50Hz Motor size 11 kW IEC (CE variant)
60Hz Motor size 10 hp TEFC
Motor speed 1800 rpm
Inlet connection 4 inch ASA/ANSI flange
Exhaust connection 3 inch ASA/ANSI flange or 3 inch NPT
Water inlet/outlet connection ½ inch NPT
Recommended cooling flow @ 85°C / 30°F 7.6 lmin-1 / 1.5 galmin-1
Water vapour pumping rate 10.45 kg h-1 / 23 lb h-1
Oil capacity 46 litre / 12 gal
Recommended oil V lube F
Noise level <83 dB(A)  
Weight 794 kg / 1750 lbs