The core instruments of Raven were designed to carry out the activated sludge process control tests created by Alfred W. West, Chief Engineer, Waste Treatment Branch of the US EPA. After testing his strategies at dozens of wastewater treatment plants throughout the USA in the 1970's, Al West published several pamphlets that have proved the test of time and science. Mr. Lynn Marshal, a co-worker of Al West, left the EPA and founded Raven in 1983 to manufacture the process control instruments necessary to carry out the control tests created by Al West. Lynn designed the instruments to be durable, simple to use, and affordable. With a manufacturing plant and staff, Lynn spent most of his time traveling and training wastewater operators and introducing his new line of activated sludge process control equipment. Lynn sold Raven to concentrate on training and consulting with troubled wastewater plants. As of 2023, Lynn is still consulting.

Raven remains a privately held design and manufacturing company with in-house engineering, testing, and quality control.


Raven serves a wide variety of industries throughout the globe with high quality instruments engineered and manufactured in the USA.

The Company has diversified into related industries such as potable water filter plants, food and beverage, pulp and paper, petroleum and mining.

Centrally located in the United States, Raven ships out of St. Louis, Missouri.


Raven manufactures all of its products and electronic circuits in the USA. The company utilizes leading edge production methods to include in-house CNC machining, 3D printing, CAD, and CAM.

Customers enjoy one-on-one dialog with product engineers regarding product enhancements and new ideas.