Why are steam pipes insulated?

After steam is generated by a boiler, it is contained in a pressurised pipeline and transported to the heat exchange equipment, and we call this transported steam network the heat network.

Steam piping must be heated to near steam temperature when it starts up, and this causes some of the steam to condense, as the steel piping and piping accessories, flanges, etc., are at room temperature.

Steam must be well insulated when it flows through the heat network, but it is still impossible to avoid dissipating heat to the environment due to the temperature difference between the external environment and the steam, resulting in partial condensation of the steam, and we call these two parts of the condensed steam as pipe losses.

Steam containing some condensate will become moist and aggressive, and with the increase of condensate, the high speed flow of steam will provide enough "head" to form a high kinetic energy "water bomb".

When we use steam, we mainly use the latent heat of vaporisation of steam. Water absorbs heat in the boiler and becomes steam, and when steam releases its enthalpy of evaporation (latent heat of evaporation) in the gas-using equipment, it will condense into condensate. It can be seen that steam as a carrier of heat, only in the need for heat where the release of heat to produce benefits, anywhere else the release of heat is a waste.

Insulation reduces heat dissipation from steam pipes and valves and saves energy. Any steam pipes, valves, flanges, joints, and containers need to be insulated.

Steam piping insulation reduces steam condensation due to heat dissipation and avoids the effects of erosion, vibration and water hammer on steam piping, valves, and heat exchangers formed by condensate moving at high speeds with the steam.

If steam piping is not insulated, the steam flow rate must be reduced, and larger steam piping is required to transport the same quality of steam. If electronic components (actuators, positioners, solenoid valves, etc.) are installed on valves, insulation facilitates stable operation of the electronic components. If the sub-cylinders, valves, and piping in the boiler room are not insulated, the ambient temperature in the boiler room can even exceed 60°C.

Steam valves that often require manual contact or operation must be insulated to avoid scalding. Or to avoid operating workers worried about scalding caused by the valve closure problem.

Steam pipeline insulation on the one hand, the use of extremely low heat transfer coefficient of the adiabatic material as a barrier, on the other hand, the use of adiabatic material formed inside the formation of an air bladder, thus using the characteristics of low thermal conductivity of the air for insulation. Piping equipment insulation is relatively easy, in accordance with the relevant norms can be constructed.

However, for steam pressure reducing valves, bellows sealed globe valves, steam regulating valves, steam traps and other sizes of steam valves, its shape is relatively complex, to consider the convenience of valve operation and maintenance, often difficult to insulate or difficult to maintain after insulation.