Problem of blockage at the pressure-taking base of differential pressure level gauges
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Is the displayed value high or low when the pressure-taking port at the root of the positive-pressure chamber of a differential pressure level gauge is blocked? What is the reason?
If the positive pressure chamber of a differential pressure level gauge becomes blocked, pressure cannot be transmitted to that chamber, resulting in an underreaded indication by the gauge. It mainly depends on the medium you are measuring; if the viscosity is high, it is recommended to install a heating system. If there are many impurities, it is recommended to install a drain valve for regular discharge. If that still doesn’t work, it is recommended to use a radar or ultrasonic level gauge ； :)
△P=P＋－P－. With positive pressure plugging, △P is smaller than the actual value, resulting in a lower reading.
If the pressure-taking port at the root of the positive-pressure chamber is blocked, it will show as high or low, and this depends on different circumstances. If the transmitter becomes clogged at the minimum differential pressure, the force acting on the positive pressure chamber of the transmitter is minimal, resulting in a lower reading ； If blockage occurs at the maximum differential pressure of the transmitter, the greatest force is exerted on the transmitter’s positive pressure chamber, resulting in an overestimated reading ； If the blockage occurs at any level of differential pressure (such as 50%), then if the actual differential pressure is below 50%, the displayed value will be too high ； The actual differential pressure is over 50%, but it is shown as being lower.
Theoretically, it might be on the low side, but in practice, when the positive-pressure end of the differential pressure level gauge used to measure the black water level in the gasification furnace gets clogged, its readings can sometimes be higher or lower than those of other gauges. Once the issue is resolved by using flushing water to clear the blockage, its readings become similar to those of the other gauges.
The 4th floor is correct; in practice, it’s rare for root valves to get clogged when there is no pressure. When they do get clogged, pressure builds up, and it becomes difficult to determine the actual reading based on this blockage. For example, if negative pressure causes a blockage, the liquid level will appear lower. If this isn’t detected in time, it can lead to contamination or poor reaction outcomes later on. And negative pressure blockage is something that most people wouldn’t think of