Chlorine mass flow meter

High requirements mean quality; low requirements mean vortex street

Report, not used. :lol

The orifice flow meters of our company have a measurement range of up to 1:70. Are you interested?

Why can the orifice plate range ratio be so high?

The high range ratio is mainly due to the differential pressure transmitter. Firstly, a key point is that differential pressure transmitters have a very wide range; however, people only use a portion of this range, such as 2 Kpa to 40 Kpa, which corresponds to a signal of 4 to 20 mA. When the flow rate is relatively low, for example, less than 2 Kpa, the flow meter may not be able to detect it and display 0. However, if you use a handheld controller to measure it, an accurate reading can be obtained. . . The meter used in our company reads the Hart digital signal from the transmitter; the differential pressure shown is exactly the same as the actual differential pressure. Therefore, the range ratio can be increased

I saw Rosemount mass flow meters in Shandong; they cost over 100,000 yuan each

This post was last edited by yuchenchf on 2017-4-22 08:20. For orifice plates or nozzles, we still need to turn to the calculation formulas specified in standard GB2624. In the formula, two values are the most important: the first is the pressure difference. I already mentioned this earlier: by reading the HART signal, it is possible to capture a wide range of pressure difference signals. . So, secondly, the discharge coefficient. Theoretically, any manufacturer can obtain an accurate Hart differential pressure signal as long as they conduct some research, but they still hesitate to use it. Why? Because of the discharge coefficient C. According to GB2624, the discharge coefficient is related to the Reynolds number (flow rate) and requires iterative calculations; it is not a fixed value. However, most manufacturers take the discharge coefficient under design conditions as a constant value and substitute it into the formula to obtain a simplified formula. Under such circumstances, when the flow rate is less than 1/3 of the design flow rate, the actual discharge coefficient differs significantly from that under design conditions, exceeding the acceptable range; therefore, the flow rate values calculated using simplified formulas are not appropriate. This is also the main reason for the 1:3 range ratio of traditional orifice plates. Conversely, by using the standard iterative formula to calculate the discharge coefficient point by point and combining it with a wide pressure difference, it is possible to achieve an effect of expanding the range ratio. Therefore, my answer is that the range ratio is determined by the differential pressure transmitter and the calculation of the outflow coefficient (integrator).

You’re speaking too professionally. However, the accurate measurement using the orifice plate is what matters; it will not be precise if it is too small or too large. So you’re setting the range ratio that high? I can’t ‘believe’ it! The differential pressure values for orifice plates generally fall within several ranges, such as 16, 25, 40, 60, and 80. What about yours?

The integrator in our home was developed by us; for the differential pressure transmitter, we chose the EJA model. The standard measurable range of differential pressure is from 0.03 kPa to 147 kPa (of course, there are also models designed for measuring very low differential pressures, which are priced separately). As long as it is within this range, we can measure it and ensure accuracy. We currently have experience with thermoelectric trade metering for fifty to sixty power plants, and there has not been a single case of trade dispute; we can provide examples from many projects involving low flow rates. Currently, the accuracy is 0.5% within a ratio of 1:20, and 1% within a ratio of 1:70. As for the differential pressure you mentioned, I’m not quite sure what it means – different flow rates correspond to different differential pressures. If you are referring to the designed differential pressure, then I would say that when designing the orifice size at the beginning, we determine the differential pressure value based on the requirements of the user or the design agency – for example, 40 Kpag. (In theory, the size of the orifice can be set arbitrarily, as differential pressure will always exist as long as there is flow.) Iteration is required only to obtain a more appropriate design differential pressure ； For example, many balance flowmeters simply involve making a few holes in a plate, and then measuring the differential pressure and discharge coefficient under design conditions; these values for differential pressure and discharge coefficient differ from those specified by the design institute. However, when installing our secondary components, there’s no need to set a range; whatever differential pressure is measured is used as-is in the calculations, because we perform iterative calculations at each point. We have many cases where users’ orifice plate flow meters give inaccurate readings; by simply replacing the transmitter and the secondary instrument, we can immediately expand the measurement range. Trade measurement particularly requires