The cone of the V-cone flowmeter has fallen off
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A few days ago, the emergency shutdown device in our company suddenly lost power, causing the main fan to stop operating. After restarting the backup fan, it was found that almost no flow rate was displayed for the main fan. Our company’s main air flow meter is a V-cone flow meter, and after inspection, both the transmitter and the pressure guiding tubes are in good condition. Preliminary analysis suggests that the vortex element of the flow meter has fallen off, preventing the creation of a pressure difference. I wonder what type of flow meter is used for measuring the main air flow rate in the emergency ventilation systems of various companies? Does the straight pipe section meet the requirements? Also, have any of the companies used balance flow meters? How effective is it? Can this type of instrument be used for measuring the main air flow rate in our company? The diameter here is DN800
Try an insert-type flow meter; after all, the pipe diameter is too large!
Using a balanced type is not a problem; in essence, the balanced type is an evolution of the orifice plate. Where the orifice plate cannot be used due to insufficient straight pipe sections, the balanced type can be employed instead. In the situation you described, the balanced design is fine, and its measurement accuracy is not worse than that of the spinal canal
Is your fan of the centrifugal or axial flow type? If the transmission medium is air, it is recommended to use a Venturi flow meter; if installation is difficult, an insert-type VeriFlow meter should be used.
The most **balanced flowmeters are very popular right now; a batch of them has been used in newly installed systems, but they haven’t been put into operation yet. It’s not clear what the performance will be like – it remains to be seen whether they truly work as well as advertised, with a precision of 0.5D at the beginning and 0.5D at the end of the flow measurement. If flange connection is used, then there’s no need for straight pipes. I hope those who have used them can share their opinions.
I have heard of cases where the cone of a V-cone flowmeter fell off.
It’s also possible that the pressure tapping hole is blocked; I suggest trying to tap it with something to see if that fixes the issue. If it doesn’t work, it’s likely that the cone has fallen off. The cone has fallen off many times; it’s the manufacturer’s negligence that’s to blame. For such a large diameter, it is better to use plug-in Ba-type or venturi devices. Let’s discuss it on QQ52496275.
It’s also possible that the pressure tapping hole is blocked; I suggest trying to tap it with something to see if that fixes the issue. If it doesn’t work, it’s likely that the cone has fallen off. The cone has fallen off many times; it’s the manufacturer’s negligence that’s to blame. For such a large diameter, it is better to use plug-in Ba-type or venturi devices. Let’s discuss it on QQ52496275.
I have long been skeptical of V-cone flowmeters, especially since some domestic manufacturers exaggerate their benefits excessively. For high-volume gas flow, it is best to use venturi meters or barometric flow meters, as these options offer the best prospects; both of these technologies have been proven effective in practice.
Hehe, at a Sinopec site as well, a V-cone fell and blocked the pipeline; later, Sinopec’s internal team recommended that V-cone flow meters should no longer be used
For our main airflow, we use venturi flow meters, and for the heat transfer oil, we employ 4 A+K balanced throttling devices which are performing well; it is not yet clear whether they can be used for larger pipe diameters.