For the 50 m 3/h and 150 m 3/h oxygen generator, the compressed air is divided into two routes after going through the first heat exchanger: one is going into the tower after the expansion of the expansion machine; the other way is further cooled by the second heat exchanger and then flows into the lower tower through the joint-1 valve. Since the air volume of high pressure air is basically unchanged, even if the opening degree of the air inlet cam of the expansion machine is unchanged, when the opening degree of the joint-1 valve changes, it will also affect the distribution ratio of expansion air volume and throttle air volume, and the corresponding high pressure will also change. This is also the case when adjusting the cam of the expansion machine separately. However, the variation of the distribution proportion of two strands of gas will affect the heat exchange condition of the main heat exchanger, and also affect the temperature before throttling (T3) and the temperature before expansion machine (T1 ), meanwhile, it will affect the temperature (T2) after the expansion machine and the temperature difference of the hot end. Therefore, when adjusting the refrigerating capacity, the three-point temperature should be referred, and the Cam and the joint-1 valve should coordinate with each other to adjust.
At the beginning of starting, the air temperature of the expansion machine is relatively high. Even if the cam of the expansion machine is fully open, the high pressure will continue to rise, which indicates that the expansion machine cannot pass through the whole air volume. At this time, the-1 valve needs to be opened slightly, and at the same time, the high pressure is maintained at the highest value. When the air intake of the expansion machine increases and the high pressure decreases with the decrease of temperature, the section-1 valve should be shut down.
At the beginning of liquid accumulation, since no liquid is produced after the expansion machine, part of the liquid needs to be produced through the second heat exchanger and the joint-1 valve. Therefore, when the temperature of the expansion machine drops to-140℃, The-1 valve should be opened (only 5 ° can be opened every time ~ 15 °), make part of the air pass through the second heat exchanger, and the temperature gradually decreases until part of the liquid is produced. At the same time, turn off the small Cam properly and keep the high pressure to produce the maximum refrigerating capacity.
When the liquid accumulates, it needs to depressurize and reduce the refrigerating capacity, if only a large Cam is opened, the air volume passing through the second heat exchanger will be reduced, and the temperature of T3 will be too low. Therefore, the big-section-1 valve should be opened correspondingly, and T1 should be kept at-155 ℃ or so.
When the expansion machine Cam has been opened to the maximum, and the refrigerating capacity is still rich, then the section-1 valve can be further opened to depressurize.
When the cooling loss is large and the liquid oxygen level drops quickly, while closing the section-1 valve, in order to avoid too little air passing through the throttle valve, the temperature of T3 is too low, it is necessary to turn off the cam properly at the same time to maintain the temperature of T3.
