Issues with the flow meter?
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The flow meter purchased by our company is of Italian origin, and the Italian engineers say that the temperature used for purging the flow meter should not exceed 120°. However, the temperature of the material flowing through our pipelines is low enough to cause it to solidify; once blockage occurs, it is necessary to use steam at 3 bar to clear it. I just want to know which engineer is correct
What is the freezing point of the process medium? If it is above 120 degrees, the flow meter needs to be reselected; if it is below 120, there is no problem. During purging, instead of using 3 bar steam, nitrogen or industrial air can be used for purging, which solves the problem of flow meter damage caused by high temperatures.
If steam purging is necessary, it is recommended to replace the flow meter. Using a flow meter beyond its temperature limit may cause sensor failure.
In my understanding: the person on the 2nd floor didn’t fully grasp what the person on the 1st floor meant; the person on the 1st floor suggested using steam at 3 bar for purging because the material flowing through the pipes had solidified due to low temperatures. What is mentioned on the 2nd floor regarding using nitrogen or industrial air for purging refers to purging when there is no blockage by materials. The suggestion on the 2nd floor is good. What is the freezing point of the process medium? If it is above 120 degrees, the flow meter needs to be reselected; if it is below 120 degrees, there is no problem. At first, purge directly with nitrogen or industrial air
A flow meter is designed to measure the flow rate of fluids that are transferred by mechanical equipment during operation; it’s not possible to simply change the medium used – instead, another type of flow meter can be used. The flow transmitter can be installed inside a control box, away from areas with high temperatures.
Why is it necessary to use a flow meter for the purging of LZ pipes? Usually, during purging, both the flow meter and the control valve need to be disconnected
There is a temperature limit; many flowmeters are sensitive to high temperatures, as they may cause the anti-corrosion lining inside to deform and lose its shape, thereby damaging the flowmeter. During steam purging, the flow meter section can be replaced with a flanged pipe, while the flow meter is treated separately; it is then reinstalled after the purging is complete. Alternatively, remove the probe, purge it, and then reinstall it.
120 degrees, it should be polypropylene.
In our unit’s paraffin oil hydrogenation plant, during this winter, many measuring elements such as flowmeters and level gauges were damaged due to freezing or became clogged as a result of the solidification of the medium. We used steam purging to resolve this issue; as for temperature, we didn’t give it much thought – as long as the pipes were cleared, that was sufficient, and no problems were detected after the purging process.
Our medium solidifies when its temperature drops below around 50. It’s not a problem during normal production, but once operations are stopped, the pipes need to be purged; otherwise they will get clogged. Moreover, removing the flow meter would disrupt production, which is quite troublesome
Steam purging will **affect measurement accuracy.** Heating can be considered as a solution.
Actually, the engineer was right; indeed, there are some flowmeters whose temperature cannot exceed a certain limit. It is recommended that you replace the flow meter with one that can withstand 150°C.
Too high a temperature can often damage the sensor, so be careful
After stopping the machine, it is necessary to purge the pipes immediately; otherwise they will get clogged very quickly, especially the flow meters. Moreover, if the machine is stopped for a short period of time (about ten minutes), removing the flow meters requires a lot of effort, which thus affects production
If solidification occurs due to low medium temperature, it is not possible to use other low-temperature media for purging; it is recommended to replace the flow meter with one that can withstand higher temperatures.
Replacing it is very expensive; we have to settle for this for now. It can only be said that we didn’t consider this factor when purchasing it, and everything is up to our management to decide
Imported flow meters are quite expensive; replacing them is not a wise choice. The temperature of the steam at 3 bar is already 130 degrees, so it’s recommended to implement proper insulation measures, as this can at least reduce the frequency of blockages.
Purging is merely a method used in the manufacturing process; there should be no temperature restrictions. It is the flow meter itself that may have such restrictions. Generally, electromagnetic flow meters can operate at temperatures below 120 degrees Celsius, while other types of flow meters can handle higher temperatures. It is recommended to select a different flow meter
It is necessary to select a new model; otherwise, the flow meter is prone to damage: lol