3GB Series Three Screw Pump

The 3GB series is a triple screw positive-displacement pump for conveying oil and oil-like lubricating liquids such as heavy oil, crude oil, diesel oil and pressurised fluid oil. It is published for media that are non-corrosive and contain no solid particles, with a flow range from 2.4 to 241.7 m³/h and heads from 60 to 250 m.

Three intermeshing screws enclose the liquid in sealed cavities and push it continuously and uniformly along the screw axis to the discharge, so the system pressure stays stable and the medium is not agitated. The published advantages of the design are corrosion resistance, heat resistance, good self-priming performance, easy maintenance and a rugged structure.

Media temperature is published up to 350 °C, which covers hot heavy oil and asphalt-type duties. Speeds are 950 r/min and 1450 r/min, motor ratings run from 11 kW to 75 kW and the NPSH required is published at 5.5 m. The series is applied in chemical fibre, petroleum, machinery, shipbuilding, glass, highway and metallurgical plants.

• Heavy oil transfer: Moves heavy fuel oil and pressurised fluid oil in industrial and marine installations.
• Crude oil handling: Transfers crude oil in petroleum gathering and transport systems.
• Diesel and fuel oil supply: Feeds burners, engines and fuel-oil circuits with a stable pressure.
• Asphalt and bitumen circuits: Handles hot asphalt-type media at temperatures up to 350 °C.
• Chemical fibre plants: Serves the pumping duties of chemical fibre production lines.
• Shipbuilding and machinery: Used on board ship and in machine-building plants for lubricating and fuel oil.
• Glass, highway and metallurgy: Covers oil transfer duties in glass works, highway plants and metallurgical installations.

1. Choose the speed deliberately: the same model gives about 1.5 times the flow at 1450 r/min compared with 950 r/min, at the cost of a larger motor, so the system flow determines the drive.
2. Check the pressure stage against the system resistance; the published table lists 0.6, 0.8 and 1.0 MPa duty points on the same sizes.
3. Confirm the medium is non-corrosive and free of solid particles, which is the published condition for the 3GB series.
4. For high-viscosity media select the insulated construction, which is published as the recommended build because it keeps the suction range high without cavitation.
5. Verify the medium temperature against the published 350 °C limit and confirm the sealing arrangement at order stage.
6. Allow 5.5 m of NPSH required, which is published for the whole model table, when the suction layout is designed.