At the beginning of starting the full low pressure oxygen generator, all the air entering the equipment is inflated through the expander, while the total expansion volume of the expander (including the standby) set by the equipment is much smaller than that of the air compressor. In addition, at the beginning, the intake temperature of the expansion machine is much higher than the design value, and the actual air volume that can enter the expansion machine is less than the design expansion volume. Therefore, there must be a part of air to be emptied first, in order to avoid the air compressor overpressure or surge.
When the liquid begins to accumulate, air is sent to the lower tower, then through the throttle throttle to the upper tower, and then combined with the expansion gas to the heat exchanger to recover the cooling. However, at the beginning, the air that can be eaten in the air separation tower is very small, because the liquid air, liquid nitrogen pipeline and regulating valve are considered according to the amount of liquid flowing through, and the specific volume of gas is much larger than that of liquid, therefore, the ability to pass through gas is limited.
With the accumulation of liquid, when the liquid appears in the main cooling, the condensing evaporator starts to work, and the rising steam of the lower tower
Part of it will condense into liquid in the main cold. The pressure of the lower tower decreases due to the condensation of a part of gas, which makes more air "inhaled ". Therefore, with the rise of the main cooling liquid surface, the amount of condensate liquid in the lower tower increases, and the air volume in the tower also increases gradually. At this time, the small air vent valve should be closed gradually to let all the air enter the tower.
