Howden North America - As the last owner of Sturtevant,they have the original documentation and continue to provide service on the larger fans.
Acme Mfg.Eng. - Acme bought the commercial line in 1986. Unknown to what extent they still support them.
Stockbridge Airco F.S.S Ltd - Phone: 0161 303 3229, e-mail: firstname.lastname@example.org
Dynamic Fan Service - Colin McArthur does site work for Stockbridge and has many years experience working on Sturtevant fans. He may be able to provide assistance. Fan production ended in the 1960s.
Clyde Process - The original Sturtevant vacuum line is still manufactured by this business
SmokStak - No idea but this forum is a good place to start.