Series T3S Three Screw Pump

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 3,000 or 3,600 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.