1. Rated thermal power: The thermal energy that the boiler can provide in a unit of time under rated conditions, generally expressed in megawatts (MW) or large calories (Kcal/H).
For boilers with thermal efficiency ≤1.4 MW, the exhaust gas temperature shall not be higher than the inlet medium temperature of 50 °C.
For boilers with a thermal efficiency >1.4 MW, the exhaust gas temperature must not exceed 170 °C.

2. Circulating water volume: The amount of water recycled in the boiler circulating water system.

3. Standard atmospheric pressure: The pressure of sea level at standard atmospheric conditions is 101.325 KPa.
Pressure: The air pressure is higher than the standard atmospheric pressure.
Vacuum: The pressure is below the standard atmospheric pressure.

4. Heating surface: The surface that absorbs heat from the heat release medium and transfers it to the surface of the heat medium, such as the furnace of the boiler, the cylinder, the tube, and the like.
Radiation heating surface: The heating surface that mainly absorbs heat from the heat release medium by radiation heat exchange, such as water wall, furnace gall, and lower abdominal wall of the drum.
Convective heating surface: The heating surface that mainly absorbs heat from high-temperature flue gas by convective heat transfer method, generally the heating surface of flue gas flushing, such as smoke pipe and convection pipe bundle.

5. Boiler thermal efficiency: The percentage of heat that is effectively used by the boiler and the amount of heat consumed by the fuel per unit time. The higher the thermal efficiency, the better the heat transfer performance.

6. steam quality: steam cleanliness, generally saturated steam with more or less traces of saturated water, with a quality of steam exceeding the standard amount of water.

7. Fuel consumption: The amount of fuel consumed by the boiler per unit time.

8. Discharge amount: The amount of sewage discharged when the boiler is discharged.

9. Natural circulation: the boiler boiler that actively pushes the water circulation by the difference of the working medium density between the down pipe outside the furnace and the rising pipe in the furnace. The circulation circuit consists of the drum, the down pipe, the header, the riser pipe, the soda water introduction pipe and the like. composition.
Forced circulation: Water or steam in the boiler should not only be driven by the difference in density of water vapor in the water, but also need to provide some pump power to circulate in the heating pipe.

10. Small boiler: steam boiler with water volume ≤ 50L and rated steam pressure ≤ 0.7MPa; hot water boiler with rated outlet pressure not exceeding 0.1MPa and hot water boiler with tap water pressure.