Problems with differential pressure flow meters

Of course, this is not it. This is just a differential pressure flow transmitter; from the picture, it can be seen that the instrument itself does not have temperature and pressure sensors, so the values displayed are certainly not the flow rate under the current actual pressure and temperature conditions. This is Rossmont’s flow meter, right? They have a flow transmitter with temperature and pressure compensation

But the unit is standard cubic feet; could it be that the instrument has already converted the current flow rate into a flow rate in standard cubic feet at the set temperature and pressure?

The unit is cubic meters; it should be displayed as cubic meters.

To be honest, I don’t quite understand what you’re saying. But here’s the thing: the gauge only measures one differential pressure value; all other values are fixed. The conditional factors used in the calculation sheets are those under standard conditions, so the units naturally are those of standard conditions

When calculating with orifice plates, the volumetric flow rate is determined based on standard conditions; errors occur when the actual operating conditions deviate from those designed, so temperature and pressure compensation is necessary.

If it is a flow meter with integrated temperature and pressure compensation, then it can be expressed in standard cubic units, as the conversion is done after temperature and pressure compensation within it.

The flow meter displays the value in standard cubic feet – there’s no mistake in that, as the unit specified in the specifications is standard cubic feet. A differential pressure flow meter actually measures differential pressure; what’s known as a differential pressure flow meter essentially includes calculations within it that convert the differential pressure into a flow rate value, which is then displayed. As for why standard cubic feet are shown, the process is as follows: based on the design temperature and design pressure specified in the specifications, the flow rate under operating conditions is calculated, and then this value is converted to the flow rate under standard conditions. Therefore, the standard-condition flow rate shown here is actually the standard-condition flow rate obtained by converting the flow rate based on the design temperature and design pressure. So when performing temperature and pressure compensation in DCS, the gas compensation formula using standard cubic meters as the unit is different from the one using cubic meters as the unit.