Does the vortex flowmeter need temperature and pressure compensation when measuring steam?

2022-11-02

Does the vortex flowmeter need temperature and pressure compensation when measuring steam?

If the user wants to achieve more accurate measurement and monitoring when the vortex flowmeter measures steam, it is recommended to treat it as superheated steam with temperature and pressure compensation. But considering the cost, the customer can only compensate for the temperature. The ideal saturated steam state refers to the one-to-one correspondence between temperature, pressure and steam density. One of them is known and the other two values are fixed numbers. Steam with this relationship is saturated steam. If not, it can be measured as superheated steam. In practical applications, the temperature of superheated steam can be very high, and the pressure is generally relatively low (saturated steam). This is the case with steam at 0.7MPa and 200°C, which belongs to superheated steam. When water is heated under pressure, the temperature of the water increases with continued heating. When the water temperature rises to a certain temperature, the water starts to boil. The temperature of the water at this point is called the boiling temperature. If the heating is continued, the water temperature will remain unchanged, and the water will begin to vaporize and gradually become steam. The boiling temperature of water under a certain pressure is also called the saturation temperature. This temperature is related to pressure. The higher the pressure, the higher the boiling temperature; conversely, if the pressure is low, the boiling temperature is also low.

1. The mass flow of steam has a great correlation with temperature and pressure, because the density of steam has a great correlation with steam pressure and temperature. The quality of steam for the same volume varies greatly depending on the pressure. For example, saturated steam P=6kgρ=3.111kg/m3 when p=7kgρ=3.6kg/m3. For the same volume, the mass difference is 14%.

2. If there is temperature and pressure compensation, the intelligent integrator matched with the steam flowmeter will measure the steam temperature and pressure at any time, which is very accurate.

3. If there is no temperature and pressure compensation, the flowmeter can only be calculated according to the common data provided by the user. The error here is consistent with or positively related to "the error between the commonly used data provided by the user and the actual data"

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