Drilling fluids and cement slurries often have a considerable amount of entrained or trapped air that may give erroneous results when determining fluid density using conventional equipment. This air volume may be reduced or eliminated by pressurizing the sample cup, which will then give more accurate density readings of the fluid itself.

The Pressurized Fluid Density Scale is similar to a standard mud balance a sample cup of known volume is balanced by a fixed counterweight at the opposite end of a balance beam. A sliding weight rider moves along the graduated scale and a level bubble on the beam indicates when the system is in balance. The position of the rider on the graduated scale indicates the density of the sample.