Its basic working principle is: through a set of automatic control devices, the liquid controller or the high, middle and low electrode probes feed back the on and off of the water pump, the length of water supply and the heating time of the furnace lining during operation; With the continuous output of steam, the highest steam pressure set by the pressure relay keeps the water level in the furnace down. When the water level is low (mechanical) or medium (electronic), the water pump will automatically replenish water, and when the water level is high, the water pump will stop replenishing water. At the same time, the electric heating tube in the furnace continues to generate heat and steam. The pointer pressure gauge on the panel or at the top immediately displays the steam pressure value, and the whole process can be automatically displayed through the indicator light.