NETZSCH NEMO SY Progressing Cavity Pump with Bearing Housing

Overview

The NETZSCH NEMO SY is the bearing housing version of the NEMO progressing cavity pump range from NETZSCH Pumpen & Systeme in Waldkraiburg, Germany. Where the NEMO BY has its drive flanged directly to the pump, the NETZSCH NEMO SY has its own large double bearing and a free shaft end, so it can be driven by practically any prime mover: standard electric motors with couplings or belts, servo motors, diesel engines or hydraulic motors. NETZSCH describes the NEMO SY as being used worldwide for demanding applications in nearly every branch of industry, with continuous, pressure-stable, gentle and low-pulsation conveying and dosing in proportion to speed. Its product page lists delivery pressures up to 72 bar for the smaller sizes, and the NEMO brochure quotes flow rates up to 500 m3/h for the series, with pressures up to 48 bar as standard and up to 240 bar for special applications.

Seven Star LLC supplies the NETZSCH NEMO SY to wastewater utilities, oil and gas operators, chemical plants, mining and process industries in the Sultanate of Oman and across the GCC. We help customers specify the right size, geometry, materials and shaft seal, and we offer sourcing and model selection support in Muscat for complete pumps and wear parts.

Operating Principle

Progressing cavity pumps are rotary positive displacement pumps. Their two conveying elements are a rotor, a round-threaded screw, and a fixed elastic stator with the same pitch length in which the rotor turns eccentrically. Sealed cavities form between rotor and stator and travel continuously from the suction side to the discharge side. Because the cavity shape stays constant, the medium is not compressed or sheared heavily, which lets the NETZSCH NEMO SY handle shear-sensitive products and solids, and the flow is almost proportional to speed, so the pump also works as a dosing pump.

NETZSCH stresses that all NEMO pumps of a given size share the same external dimensions and connections across the four rotor/stator geometries. If the required flow or pressure changes after installation, the NETZSCH NEMO SY duty can be adapted simply by replacing rotor and stator. The brochure gives a suction capacity of up to 9 m water column, reversible flow direction, installation in any position and quiet running, with temperatures from -20 to +160 °C.

Engineering Design of the NETZSCH NEMO SY

The main elements of the NETZSCH NEMO SY, as described by NETZSCH, are: a rotor in wear- and corrosion-resistant designs, including the wear-free ceramic NEMO CERATEC rotor; a stator vulcanised into its tube with seals on both sides, made in a variety of elastomers, plastics and metals, with a hopper-shaped inlet that improves product feed into the conveying chamber; a coupling rod with two gimbal joints that transmits power from the drive shaft to the eccentrically moving rotor; and suction and pressure housings with flange or threaded connections to DIN and international standards in cast iron, steel, rubber-lined chrome-nickel steel or special materials.

The feature that defines the NETZSCH NEMO SY is the bearing housing. A large double bearing gives high shaft stability, which NETZSCH notes creates ideal conditions for a wide variety of mechanical seals, and the free shaft extension accepts any drive type. The two-part shaft simplifies servicing of the rotating parts. The standard shaft seal of the NETZSCH NEMO SY is a single-acting, bi-directional, wear-resistant mechanical seal; single or double-acting seals of various makes, cartridge and special seals and packed glands are available on request. For large flows and pressures, from bearing block size NM125 SY upward, NETZSCH fits precision cartridge-type Z double seal pivot joints designed for very high loads, torques and axial forces. The NEMO SY is also compatible with the FSIP (Full Service in Place) housing concept, which allows rotor and stator service without removing the pump.

Key Features

The main features of the NETZSCH NEMO SY progressing cavity pump are:

• Bearing housing with large double bearing and free shaft end, suitable for electric, servo, diesel and hydraulic drives.
• Delivery pressure up to 72 bar for the smaller sizes, according to the NETZSCH product page.
• Four rotor/stator geometries (S, L, D and P) to match each duty for flow, pressure, solids and dosing accuracy.
• Variable, modular construction with a wide range of rotor, stator and housing materials.
• Choice of joints for each application, from the standard B universal pin joint to K joints and Z double seal pivot joints.
• Gentle, low-pulsation conveying that protects shear-sensitive products.
• Mechanical seal as standard, with alternative seal arrangements available.
• Pump connections in accordance with national and international standards.

Rotor and Stator Geometries

NETZSCH offers four conveying element geometries for the NETZSCH NEMO SY. The S geometry (1/2 lobe, two stage) gives very smooth conveying, large inlet cross-sections and low NPSH, and handles crumbly products and large solid particles. The L geometry (1/2 lobe, single stage) has a long seal line for good volumetric efficiency and long service life at high flow rates. The D geometry (2/3 lobe, two stage) is very compact at high pressures and flows, with almost pulsation-free pumping and high dosing accuracy. The P geometry (2/3 lobe, single stage) combines very high flow in compact dimensions with almost pulsation-free pumping.

Industrial Applications

NETZSCH lists environment and energy, chemical, pulp and paper, and mining among the main fields for the NETZSCH NEMO SY. In Oman and the GCC, typical duties include sludge transfer and thickened sludge feed in sewage treatment plants, polymer and lime slurry dosing, oily water and drilling mud transfer, crude and heavy oil transfer, chemical injection, and transfer of mineral slurries. The free shaft end is useful where a diesel engine or hydraulic drive is needed, such as on remote or mobile installations.

Seven Star LLC supplies the NETZSCH NEMO SY and its rotors, stators, joints and seals to plants in Muscat, Sohar, Duqm and Salalah and throughout the GCC.

Technical Specifications

Performance data for the NETZSCH NEMO SY as published on the NETZSCH product page (further sizes and data on request):

How to Order

For a quotation on the NETZSCH NEMO SY, send Seven Star LLC the medium, viscosity, solids content, temperature, required flow and discharge pressure, preferred drive and seal type. The NETZSCH NEMO brochure is available for download on this page. You can also compare the NETZSCH NEMO BY NM038BY progressive cavity pump, the NETZSCH NEMO TORNADO T2 rotary lobe pump and the NETZSCH NOTOS 3NS three screw pump. Seven Star LLC provides model selection support from Muscat for customers in Oman and the GCC.