Regarding the flow calculation method for differential pressure transmitters
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Orifice plate differential pressure flow transmitter; the range of the transmitter’s display is 0–10 kPa, while the internal differential pressure range is –0.4 to 24.6 kPa. The differential pressure value is 40 kPa. On the DCS system, the flow rate shown is 0–3200 Nm3/h, which is outside the specified range. The process team wants the automation system to increase this range, but they don’t know by how much. Should the instrument be used to calculate the actual flow rate?
The maximum is only 24.6? Then do we need to measure 40? Or did I not understand it properly?
I don’t understand. The transmitter can handle a maximum of 10 kPa, while the differential pressure type can handle up to 40 kPa. How is this measurement done? The orifice plate flow meter is manufactured by the manufacturer through technical processing based on the parameters provided by the user; it is a single unit. If these parameters change, it is necessary to inform the manufacturer to recalculate and remanufacture the orifice plate – it’s not possible to simply adjust a parameter alone.
24.6 is the upper limit; the transmitter’s display range is 0-10 kPa. As for 24.6, it should be considered a modified value
It says 0-10kpa on the header; when connected with 475, it displays -0.6-24.4, which suggests that the values have been manually adjusted
It says 0-10kpa on the header; when connected with 475, it displays -0.6-24.4, which suggests that the values have been manually adjusted
In other words, the nameplate indicates 0-10 kPa, but the actual set range is -0.6-24.4; the transmitter’s maximum range is 40 kPa, right?
Use 475 to check what the maximum allowable pressure difference inside the transmitter is; the pressure difference must not exceed this value. Is the 40KPA you mentioned the pressure difference that needs to be increased? The calculation method for expanding the range: the ratio of pressures = the square of the ratio of ranges. 25 KPA/40 KPA = the square of 3200 / the square of the new range. Just change the range to 4000, and set the differential pressure value of the transmitter to 0–40 kPa. The zero point needs to be calibrated. The zero point of the differential pressure gauge is off; do not try to shift it. It should be reset using 475 when there is no flow. Based on the information you provided, it seems that the range of this gauge has been expanded once – the original range of 10 KPA corresponding to 2000 readings has been changed to a range of 25 KPA corresponding to 3200 readings. 10/25=3200 square / 2000 square
Determine the maximum differential pressure that this gauge can measure, and then use the calculator for the flow meter to set the appropriate range
I’ve changed it from 475 to 0-60 kPa now
Yes, the label indicates 0-10 kPa, and the 475 device shows values ranging from -0.06 to 24.94. It seems that this value has been altered; now it’s set to 0-60 kPa again. The flow rate is over 2600, but there’s no clear reason for this. As for those 40 kPa values, they are the measurement results displayed by the 475 device