Problems with rotary vortex flowmeters
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1 If the measurement range for this flow meter is 600 and the displayed value is 130, why does it still show 130 when the range is increased to 1000 or decreased to 150? 2 Regarding the selection of this type of flow meter, it is said that one needs to know the maximum, minimum, and typical flow rates. But how can one determine these unknown values? Are there any handheld instruments for measurement? The pipe diameter and pressure are easy to determine. I would appreciate advice from those with more experience
This concept needs to be distinguished: the value displayed on the meter has no relation to the range; only the magnitude of the value transmitted by the transmitter is related to the range.
1. As someone working in instrumentation, whether one aims to become a mechanic or a technical manager, it is essential first to learn how to find relevant information. Values such as maximum, minimum, and typical flow rates are definitely mentioned in the design documents; at the very least, the operators in that role should have a general understanding of them. If one cannot use various means to find information, one will forever have to follow others and work as a hardworking laborer ； 2. The flow rate should be whatever it is; it is independent of the range. Whether one’s intelligence allows them to count from one to ten or makes them a math genius, 1 is still 1, 2 is still 2, and 130 is still 130 – it doesn’t change just because of the number of fingers one has ； 3. The rotameter is a type of counting flow meter; its working principle relies on counting pulses to determine the flow rate. Therefore, with the measured value remaining unchanged, the digital display reading stays the same regardless of how the range changes. Only when it is converted to analog output does the displayed value need to be multiplied by the scaling factor.
Yes, to the two major theologians*, thank you. I checked the current output options; there are two of them. The first one is 0, which corresponds to a flow rate of 0, and the second one has a current coefficient of 1 – does this refer to a range of 1*600?
The display of table headers has nothing to do with output
The header display remains unchanged, but the values you output to the DCS system will definitely change; it is necessary to adjust the scaling factor according to the range
Most instruments use a 4-20mA signal; some use a 0-20mA signal. It depends on whether the instrument in question uses 0-20 or 4-20 as its range. In most cases, it’s 4-20MA: 0 corresponds to 4mA, and 1 corresponds to 1/600 + 4mA
For this type of flow meter, the flow range for each diameter is predetermined; it is not possible to adjust the orifice size as in the case of orifice plates in order to adapt to the actual flow conditions on site. Therefore, it is even more necessary to know the process parameters in order to determine whether the flow meter is suitable and can cover the flow range required.