Why does backflow through a steam trap result in suction?
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Low-pressure steam flows through the shell side of the heat exchanger, while deionized water flows through the tube side. Why does backwashing sometimes occur during steam introduction at the inlet side?
After parking, the equipment was not drained of condensate; as the steam cooled down, its volume decreased, creating a vacuum within the system.
Is it a steam drain, or a desalinated water drain?
This is a very normal phenomenon. Steam is introduced; what comes out first is air. There is positive pressure inside the pipe, so it’s exhaust ； When the steam naturally condenses or enters a heat exchanger to condense, its volume decreases rapidly, creating a vacuum; a vacuum is thus formed in the pipeline at the front end, resulting in a pumping effect ； Once the pipeline has been fully preheated, positive pressure is re-established, and then the condensate can be discharged through the drain.
Because when steam is introduced, it condenses into condensed water, causing the pressure to drop to negative levels