1900 – Imhoff tank

The Imhoff tank obtained its name from its inventor, Dr. Karl Imhoff of Germany. The technology was developed in the Emscher District of Germany and patented in 1906 by Dr. Imhoff. The first plant was put into operation two years later. From the information available, it can be discerned that Imhoff Tanks were an acceptable…

1900 – Ringelmann chart

Municipalities began using the Ringelmann Chart to measure coal smoke in the early 1900s. The technique, developed by Maximillian Ringelmann of France in the late 1800s, measured the darkness of smoke with four different black grids on a white background, which was placed a distance away from smokestacks for a set time. Smoke control efforts…