Millwheel or water wheel are sometimes used as a charge in heraldic arms. The water wheel is often used to symbolize the food processing industry or industry in general.
The heraldric millwheel is usually stylized and may look different in the heraldic traditions of different countries.
Mühldorf am Inn (canting, since the name means "Mill village on the Inn")
The arms of Bonsmoulins, France, with a millwheel in the base
The arms of La Courneuve, France, with a millwheel in the door opening
Nacka, Sweden (Swedish variant)
Bolivar family in Biscaya