If you look at the large static steam engines of the 1850's, you'll find the use of Rotary Valves in the likes of Corliss engines. (mechanics.stackexchange.com)
ACS Valves designs, engineers, and manufactures rotary valves for metering, feeding, and airlock in bulk material processing and pneumatic conveying applications. (admtoronto.com)
Wankel got to thinking seriously about rotary pistons when he was working on rotary valves and sealing systems for Germany's burgeoning air force before World War II. (si.com)