Dual-flange level measurement range
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Seeking help: 1. For a double-flange level gauge, the measurement range is determined by the distance between the flanges. What will happen to the level gauge if the liquid in the tank is above the upper flange? 2. Use a double-flange level gauge to measure the interface; should the light phase be above the upper flange?
1: A fixed value close to the full scale will appear, no longer changing with the actual liquid level. 2: I don’t understand what you mean; do you mean that the “light phase” refers to the low-density component?
What the original poster means by ‘light phase’ is a liquid phase with a lower density； Use double-flange level measurement; the liquid level must remain full within the measurement range. If there is a gas phase within this range, the measurement values will exhibit significant deviations.
The first issue is that the gauge shows an out-of-range reading while the DCS indicates full scale. The second issue is not that; its installation is the same as that of a double-flange level gauge. When using a double-flange level gauge to measure the interface, it’s crucial that the two liquids are actually separated into layers. You need to ask the process engineers whether such separation is possible. If the liquids can indeed be separated into layers, then a double-flange level gauge will provide a better measurement result, especially when there is a large difference in density.
I have a question: if layering is possible, is the liquid level calculated by determining the pressure difference based on density, according to the proportion of each medium?
1. Overtravel, U value 2. Yes, the liquid level must be above the upper flange
Yes, the lower limit of the range is full light components, and the upper limit is full heavy components
Regarding the measurement interface, you need to know that the tank must be filled with liquid; in other words, both the liquid-phase flange and the gas-phase flange must be in contact with the liquid. Only in this way can the interface be measured. So how is the range calculated? The lower limit of the range is when the heavy-phase liquid is below the liquid-phase flange, that is, when the interface is at zero; the differential pressure in this case is (ρ_light – ρ_heavy)gh ； The upper limit of the range occurs when the heavy-phase liquid is above the gas-phase flange; that is, the interface is full, and the differential pressure is (ρ_heavy – ρ_light)gh
Well, if the heavier components are relatively pure while the lighter components are mixed with other substances, meaning that the density of the lighter components varies, isn’t it then not very suitable to use double-flange sensors for measuring liquid level?