Is it okay to connect the downstream side of the vortex flow meter to the atmosphere? Can it be measured accurately?
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Run an experiment: connect a blower upstream of the vortex flow meter and expose it to the atmosphere downstream, so that air blows out of the pipe. I wonder, can a flow meter measure accurately in this way? If that doesn’t work, which type of flow meter could be used or what improvement methods are available?
I think as long as there is a sufficiently long straight pipe section downstream to ensure that the formation of vortices and their measurement are not affected by any downstream influences, it is possible to carry out measurements by venting to the atmosphere. However, it’s definitely not possible to do this directly at the outlet using a vortex street sensor
1. The Reuleaux number must meet the requirements of the instrument. 2. Vibration levels must not be too high. 3. It is advisable to have a vibration-resistant function, such as the Yokogawa DY type
How long is long enough? Is 15-20 D okay?
Air flow can be measured using vortex flow meters; as mentioned above, straight pipe sections before and after the meter are required, with typical requirements being 15D ahead and 5D behind. The specific requirements also depend on valves, elbows, etc., located before and after installation, and the length of these straight pipe sections needs to be increased further. Or, it shall be in accordance with the flow meter installation instructions provided by the manufacturer.
A back pressure is required behind the flow meter; ensure there is enough straight pipe section behind it and install a stop valve. Do not set it to the maximum setting during testing, and also eliminate any vibrations.
May I ask, in a pipeline with a fan on each side, and a flow meter next to each fan, where the flow is reciprocating (that is, one fan is turned on while the other is turned off, then the other one is turned on and the first one turned off, in this cycle), can the flow meters still measure the flow? Or are there any bugs?
I have never done this before. Theoretically, when a fan is running, the flow meter corresponding to it should detect a normal flow rate; the flow meter on the other side should also show a reading, but the value will be incorrect. But won’t this cause the fan impeller to rotate in reverse? Can the motor handle it?