The differential-pressure V-cone flow meter fails to detect the differential pressure, resulting in a low flow rate; how can this be resolved?
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The differential pressure V-cone flow meter is giving low flow readings. After inspection, the differential pressure transmitter and its three-valve assembly are in good condition, and there is no blockage in the pressure tapping pipes. The range set for the differential pressure transmitter is 0–5.444 KPa, yet the measured differential pressure is only 0.135 KPa, which is practically zero. What could be the problem and how should it be addressed? Could it be that there is a fault or internal damage in the throttling element itself (V-cone flow meter)? The installation orientation of the throttle element and the differential pressure transmitter is correct, and the balance valve in the three-valve assembly is also tightly closed.
This post was last edited by qugd on 2015-11-6 at 21:55. Let’s see if that damn V-shaped cone is still in its original position. It is a very unreliable flow meter; the V-shaped cone used in some models is designed in a rather creative way, and it can fall off due to vibrations or impacts, or even be carried by the fluid into the downstream pipelines. In such cases, the differential pressure there should be very low. Does the original poster know that some chemical plants strictly prohibit the use of V-cone flow meters? Do you know why?
For all throttle-type instruments, it is necessary to conduct numerous fluid tests to determine the discharge coefficient; thereafter, the data is analyzed to derive a general formula for calculating this coefficient. Further constraints are applied to the scope of application of this formula in order to ensure \"nominal accuracy\", and this process requires significant human and financial resources. Initially, MC CORN did conduct a large amount of testing on V-cones in the United States, and based on those results, products with different \"cone ratios\" were developed, which is equivalent to the opening ratio. Now V is being used everywhere in the country, but it’s not clear how it was designed or how accuracy is measured. Using a venturi is also fine. @jiaguoyun
It’s possible that there are issues with the process conditions or that there’s a significant difference between the operating conditions. Instead of using a three-valve assembly, it’s better to use two two-valve assemblies. Also, check whether there are any leaks in the areas where the pressure guiding pipes are welded
When a design institute designs instruments, it specifies a operating condition, so that the manufacturer can produce the instrument based on the flow rate under that condition. In practical use, if the temperature, pressure, flow rate, and so on are far from the design parameters, then it’s impossible to make good use of this gauge. There have been serious accidents with cone flow meters: the cone fell off and punctured the pipeline, causing a hydrogen explosion. It has been banned by Sinopec for many years; it is recommended not to use such watches.
No way, that’s so scary. Sinopec still uses this type of flow meter in some of its locations. . .