Final answer:
Square root extractors are used to linearize the flow signal in order to measure pressure differential between the high and low side of an orifice plate.
Step-by-step explanation:
The square root extractors are used for measuring pressure differential between the high and low side of an orifice plate in order to linearize the flow signal. The square root extractor is a device that converts the differential pressure signal across the orifice plate into a linear signal that is proportional to the flow rate. This is done by taking the square root of the pressure difference between the high and low sides of the orifice plate. By linearizing the flow signal, it becomes easier to accurately measure and control the flow rate through the orifice plate.