Blaisdell Slow Sand Filter Washing Machine Wikipedia
The Blaisdell Slow Sand Filter Washing Machine at Yuma, Arizona is a device invented by Hiram W. Blaisdell to wash sand filters used in the treatment of drinking water. The machine was built in 1902 at Blaisdell's privately operated waterworks, which treated the muddy water of the Colorado River for local consumption. Blaisdell patented the device and marketed it throughout the United States. The Yuma filter is now on City of Yuma property, and has been preserved as the first of its kind.