A densitometer (commonly referred to as a densitometer) is an instrument used to measure the density of liquids, such as mud and sludge, flowing through a pipe. Densitometers are important tools for many industries, including mining, thinning, wastewater treatment, papermaking, and oil and gas.

Due to special application scenarios and exposure to various substances, the instrument has relatively high requirements for its own materials. For example, film switches are often used in agricultural products as control panels for better sealing and longer service life.