What is Temperature Compensation and How It Works?

Temperature compensation: Gas density meter measure the gas density of SF6 gas by measuring its pressure and converting it to a standardized pressure as if at ambient temperature of 20℃ (also known as P20). This conversion process is known as temperature compensation. Through temperature compensation, the dial on a gas density meter/monitor gives directly a P20 pressure reading, which is equivalent to gas density.

Temperature compensation is typically achieved through the use of a bimetal chip. The bimetal chip consists of thin layers of two different metals with different thermal expansion constants, bent in a U-shape. When temperature changes, the different thermal expansion ratio causes the two thin layers to expand at different rate, and, and thus cause the U-shaped chip to expand outward (when temperature rises above 20℃) or shrink inward (when temperature drops below 20℃). By joining the bimetal chip to the bourdon tube of the pressure gauge, this would effectively cancel out the SF6 gas pressure change due to temperature change. The result is a constant P20 reading regardless of the temperature variations, giving reliable and accurate reading to gas density.