Seeking advice on the isolation tank for the negative pressure chamber of a differential pressure level gauge
Thread Content
As shown in the picture, won’t the liquid in the isolation tank flow back into the container through the pipeline? Is there a check valve somewhere?
1. No check valve. 2. It won’t flow back; I don’t understand why you think it will. However, it may be diluted, changing its density; this mainly depends on the properties of the liquid in the isolation tube and on what medium is being measured. 3. After operation, the liquid level in the isolation tank should be at the same level as the upper pressure measurement point, which is indicated as H in the diagram.
I figured it out: the level of the liquid storage tank is actually much lower than the level of the pressure outlet on the tank, so there is no risk of backflow. The drawing isn’t good; it’s been drawn with everything at the same level.
It seems you still don’t understand. The drawing shows the correct method, and that’s how it is in reality as well. The pressure measurement is done using pgh; all that’s needed is for the liquid level in the isolation tank to be at the same height as the pressure measurement point. There’s no need to worry about whether the isolation tank is full or not
When the liquid level in the isolation tank rises, it flows back, ensuring that the liquid level remains at the same level as the lower side of the inner wall of the pipeline. If the liquid level is too low, condensate will form. If the temperature is kept too high due to insulation, it can also cause the liquid level in the isolation tank to drop.