Quantitative feeding problem
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Quantitative feeding is carried out through a flow meter and a secondary meter. Current issue: 120L was actually added instead of the required 100L. For a 200L quantity, 220–225L was actually added. After the quantification is completed, the quantified value will be displayed as 100L, while the total cumulative amount will be shown as 120L. At the exact moment feeding stops, the electromagnetic flowmeter still shows a flow value, which becomes zero after three to five seconds. Is it normal? How is the cumulative value of a secondary gauge calculated? Has any expert ever carried out quantitative feeding, or is involved in quantitative feeding? Please give some guidance. Thank you so much
Stopping the feed does not mean that the flow of material will cease immediately; moreover, since there is still material in the pipes, the amount will definitely be higher than actual. The control system can be used to set a compensation value to offset this excess amount.
What exactly does stopping the feeding refer to, as you mentioned? Is it a valve? Is it a pump? An electromagnetic flowmeter will definitely show a value as long as there is a medium flowing through it; if there is no medium, then either an empty-tube calibration needs to be performed or the device needs to be sent back to the factory for repair. The cumulative value is essentially similar to what happens in calculus, where small instantaneous values are added together over time, and the longer this accumulation continues, the greater the error will become.
Such quantitative measurement is inherently imprecise; only cumulative amounts can be accurate. If precise measurement is required, accurate measurement methods must be used – for example, pumps can be employed for liquids instead of flow meters.
If you use a cut-off valve to control the feed, it closes when the set value is reached. The issue lies in the time it takes for the valve to close; there is definitely some delay. Based on your data, it seems that 20 liters of feed still enters after each closure, which indicates that the valve’s position is not correct. Another issue is the time required for the valve to close. It would be better if the valve were located at the end of the feed pipe. Additionally, you can set the target value a few liters lower, depending on the valve’s closing time. Under your current conditions, achieving perfection requires modifications
Extremely small errors can be achieved through quadratic table correction coefficients. Just contact the manufacturer.
Stopping the feed involves shutting off a solenoid valve behind the electromagnetic flowmeter, so it is not considered to be due to residue in the pipeline. Because the solenoid valve is located after the electromagnetic flowmeter, everything that flows through the solenoid valve has already been measured by the flowmeter.
The valve that stops it is an electromagnetic valve. I didn’t read your message carefully at the time; now the problem has been resolved. If I had read your message carefully at that time, I might have solved the problem much faster. Thank you
This doesn’t require precise measurement, so what you mentioned isn’t necessary.
It is indeed as you said; the valve shuts off with a slight delay.
Correction factor, tried it. But it’s not linear, so it’s not suitable.