The rotary fan –
Old hat or technology with more potential?

»1 Costs for a rotary fan for an operating period of 10 years (volume flow 27 000 m³/h, 3.0 kW, 10 cents/kWh, operating time 300 days per year)

»2 Fan wheel/guide wheel combination

»3 Individual guide wheel

»4 Nominal efficiency of asynchronous motors in different efficiency classes

»5 Section through the Rotho MixAir drive unit

»6 Function of an irregular gearing

»7 Irregular gearing consisting of “four-cornered” large toothed wheel and eccentric toothed wheel on the thrust bearing

»8 Rotho MixAir air distributor (vertical section)

»9 Rotho MixAir air distributor (horizontal section)

»10 Development of the free stream on the conventional air distributor

»11 Development of the free stream on the optimized air distributor

»12 Outflow profile over the height of the blow-out slit (conventional and Rotho MixAir)

Rotho is expanding its innovative product range for the drying of heavy clay products to include rotary fans in different sizes and with different fittings. As before, rotary fans are still used in many sectors of the brick and tile industry for air recirculation. From an analysis carried out by the research department of Rotho it is apparent that there is still considerable potential for the more effective utilization of this technology, which is described in this article.

1 Introduction

The rotary fans were invented in the 1950s in Italy. Through constant further developments the rotary fan has prevailed meanwhile against large-area fans or travelling fans [1, 2, 3, 5]. Today it is the most frequently used ventilation equipment in the brick and tile industry in the industrial states [4, 6].

But does the rotary fan still fit into a time, in which fast drying processes are establishing themselves increasingly and the call for energy-saving technologies is becoming louder and louder? In order to answer this question, various rotary fan designs were tested for their...

Issue 4/2015

Positive effects of installing guide wheels in rotary fans

1 Introduction Many off-the-shelf fans now come with guide wheels fitted as standard equipment. What is referred to as guide wheels actually consist of stationary vanes situated downstream of the...

Issue 08/2014

Some positive effects of installing guide wheels in rotary fans

In the brick and tile industry, rotary fans are the most frequently employed type of ventilation device. These air distributors generate high discharge velocities that help achieve major airflow...

Issue 6/2011 In remembrance of Dr.-Ing. Karsten Junge

In remembrance of Dr.-Ing. Karsten Junge Comparison of designs and economic efficiencies of air circulation systems in dryers (Part 2)

6 Conventional air circulation systems for roof tiles Rotary fans or air walls are also employed in roof-tile dryers of conventional design. Unlike air wall dryers for masonry bricks and clinkers,...

Issue 05/2012

Rotho‘s motto: “Saving energy – always one step ahead”

Rotho is focusing wholly on the energy-saving potentials to be had by using Rotho products. Their green product support units and dryer cars, for example, are built in application of the SEC method to...

Issue 5/2011

Comparison of designs and economic efficiencies of air circulation systems in dryers (Part 1)

In remembrance of Dr.-Ing. Karsten Junge

1 Introduction All kinds of bricks and tiles (clay masonry units) are still being dried by means of air circulation in convection dryers. Thus, the air circulation system constitutes the dryers core...