How is the temperature read in the sealed oil-temperature indicating system?

How is the temperature read in the sealed oil-temperature indicating system?

• A. The pressure of the gas above the liquid is proportional to oil temperature and the gauge is calibrated in terms of temperature
• B. The bulb itself displays the temperature
• C. The oil color changes with temperature
• D. The gauge shows temperature as a digital value

Answer: (A)

In a sealed oil-temperature indicating system, the sensor is a gas-filled chamber connected to the oil. As the oil temperature rises, the gas above the oil expands and the pressure in that sealed space increases. This pressure drives the gauge, which is calibrated so the dial reading corresponds directly to oil temperature. So the temperature readout comes from a pressure gauge that has been scaled to show temperature, not from a temperature-displaying bulb, color change, or a digital value.

In a sealed oil-temperature indicating system, the sensor is a gas-filled chamber connected to the oil. As the oil temperature rises, the gas above the oil expands and the pressure in that sealed space increases. This pressure drives the gauge, which is calibrated so the dial reading corresponds directly to oil temperature. So the temperature readout comes from a pressure gauge that has been scaled to show temperature, not from a temperature-displaying bulb, color change, or a digital value.