The obvious symbol of freezing of the small air separation Tower heat exchanger is that the temperature difference at the Heat end increases, the pressure difference between the front and back of the heat exchanger increases continuously, and the temperature in front of the high pressure air throttle valve increases. This is because the tubes in the heat exchanger are blocked by grease, moisture and carbon dioxide, and the heat transfer performance is reduced.
The temperature difference at the hot end of small equipment refers to the difference between the temperature before the high pressure air enters the tower and the average temperature of the return oxygen, nitrogen and distillation. For general gas equipment, it is 5-8 ℃; for liquid equipment, it is 8 ~ 12℃. The differential pressure before and after the heat exchanger refers to the difference between the inlet pressure of the dryer (or the purifier) and the high pressure air pressure at the end of the heat exchanger. Normally, this differential pressure is hard to be seen on the high pressure gauge.
The increase of temperature difference at the Heat end does not necessarily mean that the heat exchanger freezes. Because the opening degree of CAM and joint one valve is not appropriate, the distribution amount of oxygen, nitrogen and distillation interlayer of high pressure air is not reasonable, too much processing air volume or poor Heat Exchanger manufacturing will cause the increase of temperature difference at the Heat end. However, due to these reasons, the temperature difference at the hot end increases, which will stabilize to a certain extent and will not continue to increase.
The increase of pressure difference before and after the heat exchanger does not necessarily mean that the heat exchanger freezes. because the molecular sieve in the purifier is broken, or the service life is too long, the powder filter at the outlet orifice is blocked, or the valve opening of the pipeline is too small, etc. it will cause the increase of pressure difference before and after the heat exchanger. However, the increase of the differential pressure will not cause the expansion of the temperature difference at the hot end.
When the small tube of the heat exchanger is blocked, the temperature difference between the Heat end and the front and back differential pressure of the heat exchanger increase continuously, and the high pressure air temperature behind the heat exchanger will increase. In particular, the pressure difference is getting bigger and bigger, and even can not maintain the operation. When it is found that the heat exchanger is frozen, the service cycle of the purifier should be inspected. If the freezing phenomenon still cannot be eliminated after switching, stop the car and warm it up.
