History
1895 The inventor of RAP is born
Fredrik Ljungstrom was born in Stockholm. A Swedish constructor, engineer, inventor of the radial steam turbine, designer of yachts and steam turbine locomotives, inventor of the RAP.
1908 Fredrik Ljungstrom enters the game
Fredrik Ljungstrom and his brother Birger set up Aktiebolaget Ljungstrom Angturbin (ALA) in Gashaga, located on Lindigo island near Stockholm, where their operation focuses mainly on production and development of steam turbines.
1920 The first RAP is designed
Fredrik Ljungstrom designed the first RAP.
The idea occurred to him during dinner at the Operakallaren restaurant in Stockholm, where an asthma-ridden Fredrik, suffering from thick cigarette smoke, started to think about how to improve ventilation without heat loss.
In a stroke of genius, a suffering Fredrik merged his own ideas and experiences from 1895 with the application of corrugated heat exchangers used in a high pressure steam boiler, with the idea of a regenerative heat exchanger, and the concept of the Rotary Air Prehreater was born. The first tests that he carried out in his factory in Gåshaga were paper models with paper heating elements.
He installed the first RAP prototype in the same factory.
1921 Preheaters appear in factories
The first commercial installation of RAP in a chocolate factory (AB Förenade Chokladfabrikerna) in Stockholm, which enabled fuel savings of 25%.
1923 RAPs are installed in steam turbine locomotives
Locomotives invented by the Ljungstrom brothers were a commercial failure, unfortunately they saw light of day too late. At the same time appeared diesel locomotives, and the first electrically powered units. Preheaters found their place in power plants, where hitherto flue gas leaving the boiler had a high temperature, and as a result lower efficiency.
1923 Commercialization
After the first successful experiments and commercial tests, the RAP was introduced to the world of energetics as a way of increasing fuel savings in boilers.He achieved great success, even though many existing boilers had to be modified in order to function in higher combustion temperatures. To begin with, RAPs were produced in close cooperation with ALA, but later they began to be produced on a licence worldwide.
1923 Svenska Maskinverken AB, Sweden James Howden & Co., Great Britain Maskin & Brobyggnad, Finland. ...
1925 Feuerungstechnik, Germany
1926 Air Preheater Company, USA
1927 Gadelius, Japan
Babcock & Wilcox, France
...
1935 Cegielski, Poland
…
1959 Rafako, Poland
Up to 1933, the first 1000 RAP units were produced worldwide, 100 000 were built by 1965, and in 1990 the amount of RAP’s provided surpassed 200,000. According to ASME estimates, RAP implementation has enabled saving over 4.5 billion tons of fuel, and device total working time has exceeded 1.5 billion hours.
1927 Evolution
Inception of the modernized version of RAP, without integral ventilators.
Hitherto, boilers were not equipped with ventilators, so the ventilators were installed in the preheaters and constituted a whole.
1934
The first international conference dedicated to LUVO in Berlin.
1937
ALA, the company set up by Fredrik Ljungstrom, generated a profit for the first time since its founding 15 years previously.
1949
Fredrik Ljungstrom awarded the James Watt Medal by The Institution of Mechanical Engineers, London.
1994
The ASME (American Society of Mechanical Engineers) awards RAP in recognition of it being a significant invention in the development of mechanical engineering technology.
1995
The founding of ROTOR
Compiled based on the ASME (American Society of Mechanical Engineers) „The Ljungstrom Air Preheater 1920. An International Historic Mechanical Engineering Landmark” brochure.