Abstract: A flow cell with a first section and a second section, and a gasket sealing between the first and second sections. A chamber is defined in the flow cell, having a perimeter with a narrower end and a rounded wider end. An inlet passage, outlet passage, and a sensor are arranged in fluid communication with the chamber. The inlet passage directs fluid into the chamber proximal its narrow end at an angle of between about 45° and 75° relative to the plane of gasket and the outlet passage directs fluid flow out of the wider end of the chamber at an angle between about 45° and 75° relative to the plane of gasket, the inlet passage and outlet passage being angled in opposite directions. The flow cell is useful for monitoring levels of chemicals in an industrial process stream, such as lactose levels in a dairy process stream.