Title:
Air volume controlling device for water storage tanks
United States Patent 2004417
Publication Date:
06/11/1935
Assignee:
PENN ELECTRIC SWITCH CO
Other Classes:
74/18.1, 137/112, 137/409, 137/413
International Classes:
F04B11/00; F04B49/02; F04B11/00; F04B49/02