What do vortex flowmeters need to pay attention to in trade measurement

In addition to the conventional selection and design, vortex flowmeter used in trade measurement, should also pay attention to the following points:

    1, the steam state changes on the impact of flow measurement of steam measurement, in the steam through the valve or a longer pipeline delivery, may produce changes in the state of steam:

   (1) superheated steam into saturated steam

    Superheated steam in the pipeline transport process, will produce heat loss, that is, temperature reduction. When the temperature drops to a certain level, it enters the critical dry saturated state or the oversaturated state from the superheated steam state. If it enters the dry saturated state, theoretically there will be no measurement error. Because dry saturated steam still belongs to the category of steam, and the measurement of superheated steam is generally used in the temperature and pressure double compensation method, and at the same time, it is suitable for density compensation of superheated steam and dry saturated steam.

    Solution: ① shorten the distance of the pipeline; ② do a good job of pipe insulation; ③ when the pipeline is too long, the instrument will be installed to raise the pipeline, or increase the liquid discharge device.

   (2) Saturated Steam Becomes Superheated Steam

    Ideal saturated steam state is the temperature, pressure, density is a one-to-one relationship, know one of the parameters, you can calculate the other two, so the measurement of saturated steam is generally used in a single compensation method, that is, a single temperature compensation, or a single pressure compensation. However, when saturated steam undergoes a significant pressure drop through a pressurized valve, it may be converted from saturated to superheated steam. At this time, if the density error calculated using single temperature compensation is large, the density error calculated using single pressure compensation is relatively small; if you can choose the temperature and pressure compensation, there will be no error.

    Solution: ① flowmeter installed in the upstream of the pressure-reducing device; ② if installed in the downstream of the pressure-reducing device, try to use temperature and pressure dual compensation, or single pressure compensation.

    2, select the vortex flowmeter with built-in high-precision standard algorithm software algorithm will have a greater impact on the accuracy of vortex flowmeter measurement. Such as steam density, gas compression coefficient, are the key parameters affecting the calculation accuracy.