Imhoff Cone:The Imhoff cone is a device used for measuring the settleable solids in a liquid sample. It is named after German engineer Karl Imhoff, who invented it in the early 20th century. The cone consists of a graduated cylinder with a conical bottom. A sample of the liquid to be tested is placed in the cylinder and allowed to settle for a period of time. The volume of settleable solids is then measured and expressed as a percentage of the total volume of the sample.