A vacuum chamber is formed inside the vacuum hot water unit after vacuum pumping;
After the boiler is started, the heat generated by fuel combustion is transferred to the heat medium water in the heating surface, causing the heat medium water to evaporate into negative pressure steam under negative pressure inside the furnace;
After the negative pressure steam rises and undergoes phase change heat exchange with the heat exchanger in the vacuum chamber, it becomes condensed water and flows back to the heat medium water; After the condensation of water vapor, water droplets are formed and flow back to the heat medium water, where they are heated and vaporized again, starting a new cycle process.
The body of a vacuum hot water boiler is divided into two parts, with the lower part having a structure similar to a center fired shell steam boiler, consisting of a heating surface composed of a furnace liner and a flue; The upper part is a vacuum chamber (negative pressure steam chamber), which is equipped with a tubular steam water heat exchanger to heat the circulating water flowing through the heat exchanger.
Operating principle: During the operation of a vacuum hot water boiler, the heat medium water inside the furnace absorbs the heat energy released by fuel combustion under vacuum negative pressure, boils and vaporizes into low-temperature steam. The low-temperature steam rises and encounters the system circulating water in the stainless steel heat exchanger, and the heated circulating water is sent to the user for heating or sanitary hot water. The water vapor itself is cooled and condensed into water droplets, which fall onto the surface of the heat medium and are heated again, thus completing the entire cycle process. The heat medium water continuously undergoes boiling, evaporation, condensation, and circulation within the enclosed body, so there is no need to replenish condensed water and there is no risk of empty burning.
The steam water condensation heat transfer utilized by vacuum hot water boilers has the highest heat transfer coefficient among all heat transfer conditions.