Stokes Microvac 612J

The Stokes Microvac rotary piston pump sets the standard for performance and reliability as the industrys 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 proven rugged reliable operation.
  • Low 500rpm operation for longest pump life cycle.
  • Efficient design provides maximum uptime with minimal moving parts, low rotational speed and large clearance.
  • Low ultimate blank-off with pressures down to < 2.5 x 10-2 Torr.
  • New valve deck 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) 1020 m3h-1 / 600 ft3min-1
Pumping speed 884 m3h-1 / 520 ft3min-1
Ultimate vacuum (total pressure)  
  without gas ballast <3.3 x 10-2 mbar / <2.5 x 10-2 Torr
  with gas ballast <2.6 x 10-1 mbar / <2 x 10-1 Torr
50Hz Motor size 11 kW IEC (CE variant) (x2)
60Hz Motor size 10 hp TEFC (x2)
Motor speed 1800 rpm
Inlet connection 6 inch ASA/ANSI flange
Exhaust connection 2 x 3 inch ASA/ANSI flange or 3 inch NPT
Cooling medium Water
Water inlet/outlet connection 2 x ½ inch NPT
Recommended cooling flow @ 85°F / 30°C 7.6 lmin-1 / 1.5 galmin-1 (x2)
Water vapour pumping rate 20.9 kg h-1 / 46 lb h-1
Oil capacity 92 litre / 24 gal
Recommended oil V lube F
Noise level <85 dB(A)
Weight 1724 kg / 3800 lbs