NETZSCH NOTOS 4NS Geared Twin Screw Pump

Overview

The NETZSCH NOTOS 4NS is a self-priming geared twin screw pump, the high-capacity member of the NETZSCH NOTOS® multi screw range. It delivers high flow with minimal turbulence and, because the screws are synchronised by timing gears, there is no metal-to-metal contact between them. That makes the NETZSCH NOTOS 4NS suitable for non-lubricating and moderately abrasive liquids that a two or three screw pump could not handle, across low to high viscosities.

Seven Star LLC supplies the NETZSCH NOTOS 4NS for large transfer, loading and process duties in Oman and the GCC, providing engineering support in Muscat. We work with plant owners and EPC contractors to match the size, pressure class and materials to the liquid, and to compile the documentation that project specifications require.

Working Principle

The NETZSCH NOTOS 4NS has two shafts carrying four screws in a double-flow arrangement. The drive shaft passes torque to the driven shaft through helical timing gears outside the pumping chamber, so the screws rotate in mesh without touching. Liquid enters from both ends, is carried towards the centre in sealed cavities and leaves through the discharge, which makes the design hydraulically balanced and largely free of axial thrust.

Because the gears, not the liquid, carry the torque, the pump can move non-lubricating media such as water-bearing crude, chemicals or slop, and NETZSCH notes that the 4NS can run dry for short periods depending on design. Flow is continuous and low in pulsation, and the screw profile keeps shear low, so emulsions and shear-sensitive products are treated gently.

Engineering Design of the NETZSCH NOTOS 4NS

NETZSCH nitrides the screws in alloy steel or stainless steel and shapes them to its High Efficiency Unique Design (HEUD). The casing accepts a replaceable liner, can be equipped with a heating jacket, and is offered with top-top, side-top or in-line nozzle arrangements. Helical timing gears transfer torque with reduced vibration and noise, and external bearings keep the shafts precisely located.

The NETZSCH NOTOS 4NS uses four mechanical seals operating under suction pressure. Accessories include internal or external relief valves, vibration and temperature sensors, API 682 cartridge seals and API seal plans. Materials extend from grey cast iron and chrome-nickel steel to duplex, super duplex and Hastelloy, and the pump can optionally be built to API 676 for oil and gas and petrochemical service.

Key Features

The NETZSCH NOTOS 4NS brings these strengths to high-volume pumping:

• Timing-gear synchronisation prevents metal-to-metal contact between screws and significantly reduces maintenance.
• Four-screw, double-flow design is hydraulically balanced for long bearing life.
• Handles lubricating and non-lubricating liquids, non-abrasive to moderately abrasive and corrosive media.
• Very wide capacity range, with published sizes up to 2,700 m³/h and a series rating up to 3,000 m³/h.
• Pressure classes of 16 and 40 bar on the standard table, with the series rated up to 80 bar.
• Temperatures up to 400 °C and viscosities up to 200,000 cSt for heavy and heated products.
• Short-term dry running capability depending on design, useful for tank stripping.
• Optional API 676 construction with API 682 cartridge seals.

Industrial Applications

NETZSCH targets the NETZSCH NOTOS 4NS at oil and gas mid- and downstream, shipping, power generation, tank farms and the process industry. In the GCC this includes crude and product loading at export terminals, high-volume transfer between storage tanks, heavy fuel oil and bitumen handling, slop and off-spec product recovery and process circulation in refineries and petrochemical complexes in Sohar, Duqm and the wider region.

Smaller or cleaner oil duties are often better served by the NOTOS 2NS or 3NS, or by a KRACHT KP Series internal gear pump, while highly viscous sludges with solids suit a progressing cavity pump. Seven Star LLC supplies the NETZSCH NOTOS 4NS across Oman and the GCC and supports selection, documentation review and spare parts planning from Muscat.

When preparing an enquiry for a NETZSCH NOTOS 4NS, operators should state the full range of viscosities expected, including cold-start conditions, the water and solids content of the liquid, and whether short dry-running periods are expected during tank stripping. These details decide the pressure class, the screw pitch and the seal arrangement. In terminal and refinery service the pump is often installed alongside smaller units such as the KRACHT KF80RF2-D15 gear pump for auxiliary duties, or a ALLWEILER TRILUB TRL screw pump on clean lube oil systems, while the NETZSCH NOTOS 4NS takes the main high-volume transfer load.

Technical Specifications

Key NETZSCH NOTOS 4NS data published by NETZSCH are listed below; exact limits depend on size, materials and seals.

Selected sizes from the published performance table (3,600 rpm):

How to Order

For a NETZSCH NOTOS 4NS quotation, send Seven Star LLC your RFQ with liquid properties, solids or water content, flow, pressure, temperature and applicable specifications. Our Muscat team will confirm the correct size, advise on availability and lead time, and provide the NETZSCH NOTOS brochure for your technical review. Contact us for pump selection and supply anywhere in Oman and the GCC.