ErtelAlsop ErtelAlsop is the result of the merger of Ertel Engineering and Alsop Engineering. Ertel Engineering was founded by Frederick Ertel in 1932 in New York City. He originally manufactured and sold depth filter media for the pharmaceutical industry. In 1938, he moved his company to Kingston, New York, about 100 miles north of Manhattan, on the Hudson River. In Kingston, Ertel expanded the business to include plate and frame filter presses, pumps, agitators, bottle fillers, and other equipment for liquid processing.