Three Screw Pumps

Three screw pumping technology was invented by Carl Montelius in the year 1924. He founded Imo pumps in 1931 which is now an associate company of Tushaco. Tushaco introduced this technology in India in 1970’s and is the market leader today.

Working Principle

TUSHACO Three Screw pumps employ three screw elements - one power screw and two idler screws running in three precision bores in the housing or liner. The screws are so profiled that they form a liquid tight seal between the threads. As the screws rotate, pockets/ cavities are formed where liquid gets trapped and conveyed from one end of the infinite stroke. This results in smooth, pulsation free flow with extremely low noise and vibration levels, almost impossible to be achieved by any other design of positive displacement or other types.

The power rotor does not drive the idlers as commonly believed. The hydraulic forces acting on screw flanks turn the idlers torquelessly thus reduce the friction. The idlers simply roll over the root diameter of power screw to reduce the unit pressure, centralize the power rotor and absorb the radial loads. A balance piston integrally machined on power rotor balances the axial thrusts.

While in operation, the screws are in hydrodynamic balance on film lubrication and do not require any additional bearings. The one ball bearing often used is only for axial positioning of rotor and safer operation of mechanical seals. Small rotor dimensions enable the pump to be operated at high speeds directly coupled 3000 or 3600 RPM motors or other prime movers. Such unique design and features have demonstrated excellent reliability with pumps in continuous operation non-stop for decades together without replacement of any components or maintenance on clean fluids. View Catalogue


Typical Pumped Media

Fuel Oil, Lube Oil, Mineral Oil, Vegetable Oil, Crude Oil, Glycol, Bitumen, Resins, Paint, Viscose, Pulp, Greases, Molaffes, etc.

Typical Applications

Lubrication, Hydraulic jacking, Firing, Transfer, Circulation

Typical Industries

Power generation, Marine, Navy, Oil & Gas, General Industrial, Machine Tool, Steel, Cement, Chemical, Rayon

Maximum performance data

  • Capacity : upto 2500 lpm
  • Diff. Pressure : upto 280 bar

Operating parameters

  • Viscosity : From 3 cSt to 50,000 cSt
  • Fluid Temperature : upto 80 deg. centigrade
  • Speed : upto 11000 rpm.

Material of Construction

  • Casing options : Cast Iron / Cast Steel / Fabricated / SG Iron
  • Casing Insert Options : Cast Iron / Aluminium / No casing insert
  • Screws : Carbon Steel / Alloy Steel
  • Sealing Options : Gland packing / Mechanical seal

Construction Features

  • Bearing options : Internal / External ball bearing / Bush bearing
  • Jacketing options : Front cover / gland cover / casing / foot
  • Mounting options : Horizontal Foot / Horizontal Flange / Vertical Pedestal / Vertical Tank
  • Relief valve options : Built-in / Line mounted


Relief valves, base frame, coupling, coupling guard, companion flanges, pressure gauges, electric motor, variable speed drives, etc.

Pump mounted on a base plate with above accessories as a ready to install system can be supplied.

Salient Features

  • High reliability
  • Long service life
  • Negligible maintenance
  • High efficiency
  • Self priming
  • Smooth pulsation free flow
  • Low noise and vibrations
  • High speed capability
  • Insensitive to viscosities
  • High pressure capability
  • Axial flow - no churning, chewing or shearing
  • Excellent suction capability
  • Hydraulic balancing of forces eliminates need for any bearings