Multi Screw Pump, Construction, NETZSCH, Pumps, Systems

12.12.2022

Construction of a Multi Screw Pump From NETZSCH

Flexible, efficient, and reliable: These are the main features of the self-priming NOTOS® multi screw pumps from NETZSCH Pumps & Systems. But how is a multi screw pump constructed, and what are the advantages?

We will show you the construction of a multi screw pump from NETZSCH in detail and how to benefit from it. A multi screw pump usually consists of four central components:

  • Screws
  • Pump housing with heating or cooling jacket
  • Gearbox or drive shaft
  • Shaft seals

1. Screws of the multi screw pump

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The screws are an elementary part of a multi screw pump design. A pump contains two or more counter-rotating screws, also known as rotors, enclosed in a housing. The intermeshing screws are designed with a regular, thread-like profile. The rotors and the housing then form chambers that serve as conveying spaces for the medium. When the screws rotate, these chambers continuously move out in one direction, pumping the medium from the suction side to the discharge side. Due to the helical design, the noise level is significantly lower compared to straight-toothed gear pumps. NETZSCH offers you screws in various techniques and materials, depending on the application. From grey cast iron to chrome-nickel steel to duplex, super duplex or Hastelloy steel, the variety of materials is excellent. In addition, a wide variety of helix variants are available, which are balanced and provide excellent suction performance thanks to the HEUD (High Efficiency Unique Design). Exact tolerances characterise this concept due to state-of-the-art manufacturing technology and an optimised and patented spindle profile. Even a spindle change is possible without dismantling the bearings. In addition, screws of the same size with variable pitch are interchangeable.

2. Construction of a multi screw pump: Housing with heating or cooling jacket

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Due to their characteristics, the self-priming NOTOS® 2NS two screw pumps have a long service life.

The housing is the second essential component in designing a multi screw pump. Like the screws, it is available in a wide variety of designs. Some models also offer replaceable lining and an optional heating or cooling jacket. An independent fluid circuit feeds it. The liquid is heated or cooled. This allows you to stabilise the temperature of the fluid being pumped easily. Various connection configurations are available, such as top/top, side/top or in-line. The pump housing in the FSIP® design (Full Service in Place) allows you to disassemble and assemble the pump quickly and easily without separating it from the pipeline. This design is available in two versions, the foot-mounted or the self-aligning flange. There is also a pump housing with no internal dead spaces for hygienic applications. In other words, nothing stands in the way of easy cleaning (CIP - cleaning-in-place process) and even sterilisation (SIP - sterilisation-in-place process). Thanks to the innovative design of the multi screw pump, you can pump in compliance with the strictest hygiene guidelines.

3. Construction of a multi screw pump: Gearbox or drive shaft

NOTOS® Multi Screw Pumps, Explosion, NETZSCH, Pumps, Systems
NOTOS® 4NS geared twin screw pump (top) and NOTOS® 3NS three screw pump (bottom).

Another element in the design of the multi screw pump is the gearbox. Depending on the method, multi screw pumps are driven either by a drive spindle, which transmits the torque via a thin hydrodynamic film to the two intermeshing driven spindles or using a gearbox. The spur gear ensures a frictionless torque transmission between the screws and thus guarantees a contactless operation of the pump elements. With NOTOS® multi screw pumps, the torque is transmitted by helical gears. This prevents vibrations and noise generation. The quiet running protects your equipment and pipelines.

4. Construction of a multi screw pump: Shaft sealing

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The NOTOS® 2NSH hygienic twin screw pump in FSIP® design impresses with gentle pumping, low pulsation and simple maintenance.  

To ensure proper functioning, shaft seals are also indispensable for the design of the multi screw pump. These are available in a wide range of variants, depending on the application and design of the pump. In the case of hygienic pumps, for example, the shaft seal is provided by service-friendly cartridge mechanical seals. Single-acting and double-acting variants are available, which can be operated either with a pressureless quench or with sealing pressure. All variants fit into modular housing.

Portfolio of multi screw pumps from NETZSCH

Thanks to the innovative design of NOTOS® multi screw pumps, they cover various applications, depending on the version. As a global specialist in complex fluid management, NETZSCH Pumps & Systems offers you a broad product portfolio with various variants. From multi screw pumps for hygienic and food applications to pumps for use in the chemical industry to pumping oil and gas, we have the optimal screw pump for your individual application. The complete product portfolio of the NOTOS® multi screw pump and its design: