Low temperature liquid evaporators are available in atmospheric and steam water bath types. The atmospheric evaporator consists of evaporator tubes with fins, arranged in several groups side by side, and has a larger volume. As the low-temperature liquid flows through, the surface of the evaporating fins will gradually frost. The frost should cover the surface of the evaporator. When its thickness increases, the evaporation efficiency decreases, and the evaporation amount decreases sharply over time. Generally, defrosting measures need to be taken, such as blowing away ice and frost with steam or sweeping away ice and frost with a broom, to restore the evaporation amount.
A steam water bath evaporator uses hot water to heat the low-temperature liquid inside the evaporation tube, causing it to evaporate. Before the low-temperature liquid flows in, pure water (chlorine free) should be first poured into the evaporator to the overflow port, and then steam should be slowly introduced, and the temperature control should be set at around 60 ℃ (not too high). First open the gas outlet valve, then slowly feed in the low-temperature liquid, adjust the flow rate to the required flow rate using a flow regulating valve, and control the outlet gas temperature to be greater than -15 ℃ to prevent frost formation in the outlet pipeline.
During winter, when the evaporator is not in use, attention should be paid to discharging the remaining water in the evaporator cylinder, blowing in a small amount of steam, or maintaining an overflow state. The water temperature should be controlled at 20-40 ℃ to prevent the water bath from freezing. The steam pipeline trap should be kept in good working condition. The coils of liquid evaporators should generally be managed as pressure vessels. Therefore, it is necessary to conduct regular inspections according to the national regulations on pressure vessels, and only after passing the inspections can they be put into operation.
