Where should the differential pressure gauge be installed?

The original poster, please provide a picture; this description isn’t very clear, making it difficult to answer.

The device we use is similar to what you described: there is a pressure gauge at the bottom of the container, and another pressure gauge at a height above the highest level of the liquid in the container; these are used to measure the liquid level. Obviously, it’s not possible to move the gauge at the top to another location!

This change might have no effect at all, or it could cause measurement errors. The resistance of the pipeline and changes in elevation can cause pressure differences at various points, but the extent of this effect depends on the medium flowing through the pipeline and the flow velocity. It is best to first make an opening below and modify it, retaining the original root valve and some of the pressure lead pipes. Flexible joints are left in the modifications, so that they can be changed back without using fire if necessary. 　

The process is not clear, so I don’t dare to draw conclusions casually, but I recommend installing two transmitters and then creating a differential pressure in the system configuration.

It is best to conduct measurements on-site; after all, with such long pressure transfer pipes, various factors that can cause changes in density must be taken into account. The best approach is to make measurements at the flange at the top of the tower, with the electrical signals sent to the ground (if it’s necessary to monitor the values on the ground, otherwise they can be viewed directly on the DCS). Accuracy in measurement is of primary importance, and this method requires little maintenance.

It’s not very clear. The pipeline connection point is usually the wiring interface, while for differential pressure gauges, it’s the pressure sampling port that is related to the upper and lower positions; that’s why. . . It’s better not to speak; talking too much leads to mistakes: lol

This post was last edited by HEJIYUER on 2015-10-13 at 20:06. I guess the original poster (PIPING) is asking: Can the differential pressure gauge of the tower be installed at the bottom of the tower? 1. What is actually measured here is the differential pressure of the tower, which generally does not exceed 10 KPA. 2. Holes are made in the tower to lead out pressure guide tubes, and condensate will form and accumulate within these tubes (as the tray operates at gas-liquid equilibrium); this hydrostatic head of liquid will affect the measurement of the differential pressure, on a KPA scale. 3. To this end, the differential pressure gauge is preferably placed on a platform at the top of the tower, slightly higher than the pressure tapping point, so that the condensate in the pressure guiding pipe can flow back to the tower by gravity. 4. In actual design, both of these pressure guiding pipes need to extend upward along the tower (they may also be considered as pipeline attachments). Additionally, insulation should be provided around these pipelines so that the light components of the material can evaporate inside them; this results in non-condensable gas filling the pressure guiding pipes – meaning there is no liquid phase inside them, which ensures accurate differential pressure measurement. @jiaguoyun

I’ll post the PID and pipeline model when I have time, asking everyone for their explanations. Thank you all

If the tower is relatively tall, it is recommended to install a pressure gauge at both the outlet pipeline at the top of the tower and the inlet at the bottom of the tower; then, the difference can be calculated within the DCS by creating a new point

If the tower is relatively tall, it is recommended to install a pressure gauge at both the outlet pipeline at the top of the tower and the inlet at the bottom of the tower; then, the difference can be calculated within the DCS by creating a new point