Issues related to level differential pressure transmitters
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The header is at the top, while its pressure tapping pipes are installed downward; is it necessary to perform a shift when setting the instrument’s range?
Is it a regular differential pressure transmitter, or a level gauge made using pressure lead pipes and a three-valve assembly? If it is a regular transmitter, then this installation is incorrect.
Yes. Since it’s already set up like this, is migration necessary?
In my opinion, it’s not necessary, no matter where you place the header. The force acting on the positive pressure chamber is the force exerted at the location where the downward pressure conduit connection is situated, as you mentioned. If it is a double-flange type, then migration needs to be considered, as the oil in the capillary also generates pressure.
Isn’t there a height difference between the positive and negative pressure introduction pipes? Isn’t it necessary to carry out some adjustment?
Whether migration is necessary depends on whether the pressure difference across the positive and negative diaphragm chambers of the transmitter at the zero liquid level is zero; if it is not zero, migration is required.
Is there a clear conclusion? ! !
The upper floor is the correct answer. Now that the gauge has been installed, is it at zero when there is no liquid level? Personally, I think it should be zero. . . Because when there is no liquid level and the balance valve is not open, the positive pressure chamber and the negative pressure chamber are connected to each other; thus, there is no pressure difference, the PV value is zero, and therefore no migration is required
Under normal circumstances, zero-point adjustment is required for differential pressure transmitters used to measure liquid levels, and the amount of adjustment depends on the installation scheme.
The original poster can roughly sketch a diagram on paper: lol
The differential pressure transmitter of the pressure guiding tube is related to the installation location of the gauge; your measurement range is from the location of the gauge to the pressure sampling port on the negative pressure side