Regarding the flow measurement range issue
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Taking a flow meter with a usable range of 25–250 m3/h as an example, we* usually choose one with a range of 0–xx m3/h； Assume a range of 0~50 m3/h is selected, but are the values that can actually be measured only 25~50? Is a flow rate below 25 displayed as 0?
What can be displayed is 0 to 50, unless you enable low-flow cutoff
The available range is 25–250. Is it impossible to measure flow rates below 25, or are the readings inaccurate?
Any flow rate must be measured at full pipe capacity to obtain accurate results; therefore, in many cases a low-flow cutoff is implemented to prevent incorrect measurements – that is, when the flow rate falls below a certain value, it is automatically set to 0
Taking a flow meter with a usable range of 25–250 m3/h as an example, we* usually choose one with a range of 0–xx m3/h； Assume a range of 0~50 m3/h is selected, but are the values that can actually be measured only 25~50? Is a flow rate below 25 displayed as 0? The available range is 25–250. Is it impossible to measure flow rates below 25, or are the readings inaccurate? Readings will be available below 25, but the range of 0–25 is outside the specified range, so accuracy cannot be guaranteed. Readings between 25 and 50 are accurate
Vortex flow meters and float-type flow meters inherently have a function to cut off measurements at low flow rates; when the flow rate is too low, no reading is possible and the display shows zero. Additionally, due to the inherent zero drift in each flow meter as well as the imprecision in measuring low flow rates, most instruments are equipped with a function to cut off measurements at low flow rates, with this threshold typically ranging from 2% to 20%.
This post was last edited by liuyuqian on 2016-9-6 at 13:22. First, it is necessary to clarify the definition of \"range\": Range = upper measurement limit – lower measurement limit； The range is a numerical value, not a range ； 0~50m3/h indicates the measurement range, with a scale of 50m3/h. Taking the \"flow meter with a usable range of 25–250 m3/h\" as an example, this means that the flow meter can maintain the required measurement accuracy across any range within the 25–250 m3/h range ； If the flow meter’s range is less than 25 m3/h or greater than 250 m3/h, its measurement accuracy cannot be guaranteed. The maximum measurement range of this flow meter is 0~250 m3/h ； The minimum measurement range is 0~25 m3/h. Hope this is useful to you
What do you think, OP? First, tell us what you do. If you’re majoring in engineering, I’ll let you know; if you’re majoring in instrumentation, well, hehe~
“A flow meter with a usable range of 25–250 m3/h” – in my understanding, this refers to a flow transmitter with a measurement range of 0–25–250 m3/h. The selected range is the actual current range; in this example, it is 0-50 m3/h, so the values that can be measured actually range from 0-50 m3/h.
It won’t show as zero; it’s just that the measurement error is large when the value is below 25.....
1. What is the available range? If it exists, it can be considered the measurement range for ensuring accuracy. It is also limited solely to the measurement range that a flow meter can achieve under the most ideal conditions. 2. The actual measured range is definitely not 25~50, unless values below 25 are excluded. 3. If you read a few more books or look at samples of different flowmeters, you won’t ask such questions anymore.