What is the purpose and rationale for installing U-tubes between Section 1 and Section 2 of evaporation?
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What is the purpose and rationale for installing U-tubes between Section 1 and Section 2 of evaporation?
It is mainly the liquid seal effect that allows the first and second evaporation stages to maintain their respective vacuum levels. The height is mainly determined by the pressure difference between the first and second stages of evaporation.
The liquid seal prevents gas from one section from leaking into the other, thus avoiding disruptions to the vacuum level
There is a pressure difference of about 0.25 kilograms between stage 1 and stage 2; this pressure difference is sufficient to maintain a liquid level of over two meters. A U-shaped tube is installed to prevent gas from passing between stage 1 and stage 2. The typical design length for such a tube is around 5 meters, ensuring that no gas leakage occurs even if there is a disruption in the flow at stage 1
It is similar to a water seal: it maintains a pressure difference between stage 1 and stage 2, while also ensuring the same amount of evaporation in both stages, thereby preventing the liquid level from rising too high and causing the stages to mix together.