General information

Construction of one-stream centrifugal fans is adjusted to work in difficult conditions of land and marine industry environment. All products and their equipment are produced according to actual EN norms as well as according to implemented quality norms ISO 9001:2008, ISO 14001:2004 and PN-N 18001:2004.

In standard the fan consists of steel and welded housing, impeller, motor pedestal and base frame equipped with vibration dampers. Presented flow parameters are calculated for medium with 20°C temperature and density 1,2 kg/m3.
All fans are intended for work in ambient temperature range -20°C-40°C; all other temperature ranges demand additional technical agreements.

Equipment in basic execution is intended for work with medium -10°C- 80°C. Fans equipped with cooling disc may work with agent up to 300°C, non-standard executions enable work up to 750°C.
Impellers produced by Nyborg-Mawent are balanced in G6,3 class or G2,5 on request. The fans comply with norms and requirements regarding vibration level according to ISO 14694:2003. Allowable vibration level is specified in fan’s technical documentation. Each finished product is tested in terms of its work parameters.

WPSS nap1zfk 125 nap2WPSS nap 4
Direct drive (1) – impeller is mounted directly on motor’s shaft; for horizontal and vertical work .Indirect belt drive (2) – the fan is driven with motor by means of belts;Indirect coupling drive (4) – the fan is driven with motor by means of coupling.

Types of drive

Type of driveStandardCooling discInsulation and cooling disc
NAP1[ up to +80℃up to +220℃ *up to +250℃ *
NAP2up to+100℃up to +300℃up to +300℃
NAP4up to+100℃up to +300℃[up to +300℃ ]

*consultation with producer is required;
Fans in execution for agent temperature up to 750°C are produced on special request.

Direction of rotation

We assume two possible directions of rotation: RD (right) and LG (left) looking from motor’s side. It refers to all types of drives.

Mounting positions

It is given in degrees after direction of impeller rotation is specified. On customer’s request other mounting positions are also produced.

In standard it is made of ordinary steel, in special execution it can be made of stainless steel (AISI 316L /304) or aluminium. All impellers are statically and/or dynamically balanced according to norm BN-79/1380-13 in two accuracy classes – G6,3 and G2,5 according to PN-77/M-04000 equal to dynamic and static balancing.

  • Standard – intended for clean air pressing (dust contend must not exceed 0,3 g/m3)
  • Special execution – intended for contaminated agent pressing (dust content must not exceed 3 g/m3)
  • Conveying fans – can press the agent with maximum dust content 0,2kg/m3.

There is also a possibility to produce a specially designed impeller adjusted to required working point.

Example of impeller.

In construction of fans with indirect drives (2) and (4) the impeller is mounted on the shaft embedded on rolling bearings. We use two types of bearings: ball and barrel.

Bearings can work in maximum temperature of 80°C.

The bearings as well as their casings are greased with certified greases dedicated by their producers. Using an appropriate quality greases ensures a long term and failure-free operation of bearing gears.

In standard constructions we use bearings of world-renowned producers for mechanical sizes from 60 to 190.

Example of bearings from FAG.

In standard execution fans are not equipped with any sealing of shaft’s transition through the casing.

However for our customers’ special requirements we use:

  • Frictional sealing with the use of brass and plastic (simmerings);
  • Labirynth sealing which provides high efficiency during the fans’ work;
  • Brass or graphite sealings for temperatures <300°C.
  • Special sealings for temperature up to 750 °C

It must be noted that none of above provides a 100% sealing.

Its main task is to increase the stiffness and durability of the fan. Additional advantages are as follows:

  • Easy mounting on steel constructions;
  • No need of expensive fundaments building.

In order to stabilize the fan’s work and minimize the vibration occurrence we use base frames equipped with a set of vibration dampers. In this arrangement the fan is screwed into intermediate frame which hides the vibration dampers underneath. Stiff frame construction together with well selected vibration dampers provide appropriate amortization and insulation between the fan and the fundament. Size, quantity and type of vibration dampers are selected on the basis of system’s static load.

Example of the base frame with vibration dampers.

We use 3-phase induction motors from Polish and foreign producers with cage impellers in IP55 execution.

Usually we use motors of following classes:

  • IE2 – high efficiency motors
  • IE3 – the highest (premium) level of efficiency.

Purchased motors can be ready to work with frequency converter. Additionally they can be equipped with encoder, PTC. vibration and temperature sensors and heaters.

In the case when ambient temperature is higher than 40°C, the power drop must be taken into account, therefore adequately higher power of motor must be selected.

For fans in explosion proof execution we use Atex certified motors.

In the case of noise limitation to the required level we make the insulation of casing, which also functions as thermal protection. Our insulation is made of low conductance mineral wool with high resistance against steam diffusion and soundproof properties.

Thermo-acoustic insulation can be produced in a few options:

  • Thermo-acoustic insulation of impeller;
  • Acoustic insulation of propulsion, electric motor and the base-frame of the fan.

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