The Column (Large Diameter) is a large watertight process column made of clear acrylic plastic. It comprises three ports at the top and bottom of the column which can be connected to the process loop or sealed off with a cap. A ruler is affixed to the column to make simple visual measurements of the level of liquid inside the column. Pressure ports allow for the measurement of the pressure at the bottom and at the top of the column. A safety valve is installed at the top of the column to prevent the pressure from exceeding a safe limit.

The column features an industrial flange that can house one of many optional level sensors and it contains a stainless steel baffle plate to reduce turbulence at the bottom water intake. It comes equipped with a bubbler tube to infer the level of fluid in the column. The column can also accommodate a variety of sensors inserted at its base.