Problems with double-flange level gauges; seeking expert assistance
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Recently, I was installing a level gauge for a tank – a double-flange type – and encountered a problem. Theoretically, its migration amount should be fixed at -ρ silicone oil gH0; this value is determined once the installation is complete. However, due to poor communication during the design and selection phase, the actual migration amount after installation turned out to be -68 KPa. The operating range of this level gauge, on the other hand, is between -50 and +50 KPa. As a result, it’s not possible to calibrate this level gauge. Have anyone encountered such a problem before? Is there any way to solve it?
Is the sensor’s range ±50Kpa?
The measurement range is from -50 kPa to 50 kPa, which indicates that the instrument’s range is 100 kPa. The typical offset is of ±100 kPa, so an offset of -100 kPa should be achievable.
But isn’t the amount of migration equal to -ρ silicone oil * g * H (the distance between the upper and lower flanges)? The flanges of our tanks are fixed, so H definitely can’t change; the other two values are also fixed. It seems that there’s no way to address this issue except by making major changes
The measurement range of modern transmitters now includes the amount of migration; whether it is silicone oil or not, this amount of migration must not exceed the upper and lower limits of the measurement range. I think that if it’s not possible to make modifications on-site for the time being, considering reducing the range might be an option – that is, by adding elbows on the positive or negative pressure side and decreasing the distance between the flanges; this should work. At the same time, care must be taken to prevent blockages. Personal opinion, for reference only
Can you provide the transmitter model?
1. It can be replaced with an electronic differential pressure level transmitter; there is a primary and a secondary gauge, and these are connected to each other via a cable. As long as the cable is long enough, it can meet the requirements for measuring height. 2. A pressure transmitter can be installed at each of the existing positive and negative pressure sampling points. By using the logic in the control system to determine the pressure difference and comparing it with the specified range, the liquid level can be calculated. The second method requires the installation of cables, but it allows the use of existing pressure transmitters, thus saving costs. The first method is simple and fast, but it requires additional funding. I hope this is useful to the original poster
Thank you so much. I suddenly thought that migrating to DCS might solve the problem