Do you know the function of the throttle valve of the small oxygen concentrator?
When a small oxygen generator uses a liquid nitrogen throttle valve to adjust the purity of liquid nitrogen, it can be found that adjusting the valve within a certain opening range has little effect on the purity of liquid nitrogen; while at a certain position, the valve opening changes by 1° ～2°, the purity of liquid nitrogen will change greatly. In other words, the change in the degree of opening of the liquid nitrogen throttle valve and the purity of the liquid nitrogen is not a simple proportional relationship, but the most sensitive position for adjustment.
This phenomenon has a lot to do with the structure of the top of the lower tower. The top of the lower tower is connected to the main cooling tube. Nitrogen rises into the main cooling tube and then condenses into liquid nitrogen downflow. A liquid nitrogen tank is provided at the bottom of the main cooling. The liquid nitrogen in the liquid nitrogen tank is throttled to the upper tower through the liquid nitrogen pipe, and the liquid nitrogen condensed in the condenser tube in the inner ring of the liquid nitrogen tank will directly return to the lower tower as the reflux liquid. When the opening of the liquid nitrogen throttle valve is too large and the liquid level in the liquid nitrogen tank is too low, the liquid nitrogen pipeline will pass through the vapor-liquid mixture. At this time, the amount of liquid nitrogen condensed in the main cooling will decrease accordingly. The reflux of the tower is also reduced, so the purity of liquid nitrogen is lower.
When the liquid nitrogen throttle valve is closed, the amount of vapor passing through the throttle valve gradually decreases, the reflux liquid of the lower tower increases, and the purity of the liquid nitrogen gradually rises. When the liquid nitrogen throttle valve is closed so that no steam passes through the pipe, and the liquid nitrogen in the liquid nitrogen tank is not full to overflow, even if the liquid nitrogen throttle valve is closed, the reflux flow rate of the lower tower will not be changed. How much, therefore, the purity of liquid nitrogen is basically unchanged. When continuing to close the throttle valve, so that all the liquid flowing into the liquid nitrogen tank cannot pass through the throttle valve, and the liquid level rises to the point that some of it overflows back to the next tower.