Instruments: [Weekly Question] Week 43 of 2011: Issues related to the installation of differential pressure instruments or transmitters
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This post was last edited by denghl on 2012-11-26 23:09. Topic: Where should differential pressure instruments or transmitters be installed when measuring the flow rate of steam or liquids? Hint: They should be installed below the component from which the flow is measured
This post was last edited by denghl on 2012-11-26 23:09. Reply 1# Baghdad should be placed below the component from which it draws its supply.
This post was last edited by denghl on 2012-11-26 23:09. It should be placed below the component from which it draws data.
Does it refer to the location where the pressure tap is installed? The gas is on top and the liquid is at the bottom, right?!
This post was last edited by denghl on 2012-11-26 23:11. It should be placed below the component from which it draws data.
This post was last edited by denghl on 2012-11-26 at 23:09. 1. When measuring gases, the pressure tapping should be located at the top or side of the pipeline, and the transmitter should also be installed above or beside the pressure tapping, so that liquid can flow into the pipeline. 2. When measuring liquids, the pressure tapping should be located on the side of the pipeline to prevent the accumulation of residues; the transmitter should be installed on the side or below the pressure tapping to ensure that gas can flow into the pipeline. 3. When measuring steam, the pressure tapping should be located on the side of the pipeline, with the transmitter installed below the tapping, to ensure that the pressure conduit is filled with cold water and no steam enters the measuring elements of the transmitter directly
This post was last edited by denghl on 2012-11-26 at 23:09. The differential pressure gauge should be placed before the transmitter, with the probe located in the center of the pipeline
This post was last edited by denghl on 2012-11-26 at 23:10. It should be placed below the source component; this helps to prevent bubbles from forming inside the measurement pipeline, and it also eliminates the need for an exhaust valve at the highest point of the pressure transfer tube.
This post was last edited by denghl on 2012-11-26 at 23:10. When measuring liquid and steam flow rates, it is preferable to use differential pressure instruments placed downstream of the throttling device; this helps to prevent the formation of bubbles in the measurement pipeline, and it also eliminates the need for an exhaust valve at the highest point of the pressure guiding pipes
This post was last edited by denghl on 2012-11-26 at 23:10. As the name implies, a differential pressure transmitter measures the pressure difference, that is, △P=ρg△h. Since oil tanks are usually cylindrical, the area S of their circular cross-section remains constant. Therefore, the weight G = △P·S = ρg△h·S; with S being constant, G is directly proportional to △P. In other words, as long as the △P value is detected accurately – and it is inversely proportional to the height △h – then even when the temperature changes and the volume of the oil expands or contracts, causing the actual liquid level to rise or fall, the measured pressure remains constant. If the user needs to display the actual liquid level, medium temperature compensation can also be introduced to address this issue.
This post was last edited by pz020302 on 2011-11-7 at 11:29. Don’t understand the question? Does it refer to the location where the transmitter is installed? When measuring liquids or vapors, it is advisable to place the transmitter below the pressure tapping point, as this ensures that the pressure lead is always filled with liquid. In the case of on-site installation, where the process pipeline remains filled at all times, and the pressure is taken at a 45-degree angle downward, if the pressure lead is short enough (more than 200 mm but less than 50 mm), it is possible to install the transmitter upside down, either below or slightly above the pressure tapping point, and add a tee and a drain valve at the lower position