Gauge pressure: refers to the pressure displayed on the pressure gauge, which is measured based on atmospheric pressure and is measured in MPa.

Absolute pressure: The pressure measured in MPa based on the absolute vacuum. Absolute pressure = gauge pressure + one atmosphere pressure (approximately equal to 0.1013MPa).

Saturated steam: refers to pure steam at a certain pressure corresponding to the boiling point temperature of water. That is to say, if the water that has reached the saturation temperature is heated further, the temperature of the water will not increase, but will only continue to evaporate until it is all evaporated; The steam thus produced is called "saturated steam"

Latent heat (heat of evaporation): refers to the amount of heat required to convert 1kg of boiling water into 1kg of steam (expressed in KJ). This heat is equal to the amount of heat released when 1 kg of steam is condensed into 1 kg of water (the state of the substance changes).

Sensible heat: The heat that heats water from the melting point (i.e., freezing point) to the boiling point, and the amount of heat absorbed is called "sensible heat". This heat can be measured with a thermometer, and there is no change in the state of the heated object.

Total steam heat: refers to the sum of the heat (sensible heat) and latent heat of saturated water, expressed in KJ.

Pressure/Temperature Relationship: Any pressure of saturated steam corresponds to the corresponding saturation temperature. For example, a saturated steam of 1.242 MPa corresponds to a saturation temperature of 193.15 °C. (See columns 1, 2 and 3 of the table below).

Saturated water specific volume: refers to the volume per unit mass, expressed in m3/kg.

Specific volume of steam: refers to the volume of steam per unit mass, expressed in m3/kg.