The high pressure air inlet valve controls the air volume entering each compartment of the main heat exchanger respectively to adjust the temperature difference of the Heat end between the compartments. When the temperature among the outlet of oxygen, nitrogen or distillation is inconsistent, the air volume entering this partition can be changed. For example, when the temperature of oxygen is lower than the outlet temperature of nitrogen, a high-pressure air inlet valve with a large oxygen partition can be opened. When the valve is fully open and the oxygen outlet temperature is still lower than the nitrogen outlet temperature, you can close the small nitrogen partition high pressure air inlet valve. And vice versa. The smaller the temperature difference between the partitions, the better, the maximum is no more than 2℃.
The high-pressure air inlet valve of the expansion machine is the pass valve of the high-pressure air entering the expansion machine. This valve is in the open state at ordinary times. When the equipment breaks down and there is an emergency power failure, the expansion machine should be closed before starting and stopping. This valve is not used for adjustment in principle, but in the late stage of starting, the expansion machine Cam has been in the minimum air intake position, after expansion, the air temperature is lower than-160℃, and continues to decline, if we use the method of enlarging the high-pressure air throttle to reduce the expansion volume, it is bound to reduce the high-pressure pressure, increase the temperature in front of the high-pressure air throttle, decrease the liquefaction rate after throttling and reduce the liquid production, it will extend the entire startup time. Therefore, the short-term use of the high pressure air inlet valve of the expansion machine to control the temperature after the expansion machine will be beneficial to the accumulation of liquid in the tower. Close the high pressure air inlet valve of the small expansion machine, then the high pressure of the heat exchanger will rise, the high pressure in front of the machine will drop, the medium pressure will drop, the temperature will rise, and the liquid oxygen level will rise. It is contrary to the above situation to enlarge. When reducing pressure, the high pressure air inlet valve of large expansion machine should be opened first, and then the cam mechanism should be opened. However, it should be noted that the valve should not be opened too large, as long as the two pressure gauges in front of the heat exchanger are the same, so as to cut off the air source quickly in case of emergency power failure and prevent the expansion machine from flying.
