Under what circumstances can double flanges be used without being relocated?
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I’d like to ask for help from everyone regarding double-flange transmitters. Install it top and bottom. In this installation scenario, can it be used normally without migration? Under what circumstances can it be used this way, and must it be used this way? It cannot be tested during migration. The range is 0–300 kPa; when the tank is empty, the instrument shows 0 after installation and outputs 4 milliamps. When the tank is removed and placed horizontally, it shows a certain pressure and the current value corresponds as well. How is that possible? ? ? ?
There is no negative pressure inside the tank; how can such a situation occur? Where has the pressure on the negative pressure side gone?
It won’t work without migration. By empty can output of 4 milliamps, do you mean that after installation, someone performed a zero-point migration, thereby transferring the differential pressure value from the empty can state?
No, when the tank is empty, the differential pressure shows as 0, and the output is 4 milliamps. So it’s not migrated yet? How is it possible to use it normally? If it’s migrated, then it won’t work. I’m puzzled too; I can’t figure it out.
There is another scenario where someone performs a zero calibration directly with an empty tank.
“After installation, the gauge shows 0, with an output of 4 milliamps; when it is removed and placed horizontally, it indicates some pressure, and the current value is also correct. ”It indicates that your transmitter was migrated before it was installed.
It has been migrated; after installation, 4 milliamps are indicated. Shouldn’t the gauge display the pressure value corresponding to 4 milliamps?
The pressure value corresponding to 4 mA is set on the display instrument; if the transmitter outputs 4 mA accurately, it indicates that the liquid level at the site is zero.
The transmitter displays different values after zero-point calibration and zero-point shift; in the case of a shift, an empty tank will still show a differential pressure (the differential pressure in the capillaries on the positive and negative pressure sides), but the current output is 4 milliamps. If it is calibrated at zero, the transmitter will display 0 KP when there is no tank present, and the current output will still be 4 milliamps.
I understand what you mean. The situation you described on the fifth floor is possible; I’m wondering if such actions were indeed taken on site. It’s very likely that I overlooked that possibility.
Place the transmitter at the same height as the lower flange