Working principle of differential pressure flowmeter | Formula for calculating differential pressure value?

『Working principle of differential pressure flowmeter』Related information(clamp on meter|electromagnetic meter|venturi meterrotameter|orifice meter|ultrasonic flow meter|mass flow meter|coriolis mass flow meter|coriolis flow meter|magnetic flow meter|magmeter flow meter|magflow flow meter|mag meter flow meter|electromagnetic flow meter|vortex flow meter|turbine flow meter|thermal mass flow meter|thermal flow meter|rotameter flow meter)

What are the disadvantages of differential pressure flow meters?

2. Formula for calculating differential pressure value? The measurement principle of differential pressure flowmeter is based on the principle of mutual conversion of mechanical energy of fluid. The fluid flowing in a horizontal pipeline has dynamic pressure energy and static pressure energy (potential energy is equal). Under certain conditions, these two forms of energy can be converted into each other, but the total energy remains unchanged. Taking the volumetric flow formula as an example: Qv=C εΑ/sqr (2 Δ P/(1- β ^ 4)/ρ 1), where: C outflow coefficient; ε coefficient of expansion Α cross-sectional area of the orifice of the throttling element, M ^ 2 Δ P differential pressure output by the throttling device, Pa; β diameter ratio ρ 1 density of the measured fluid at I-I, kg/m3; Qv volumetric flow rate, m3/h According to the compensation requirements, temperature and pressure compensation need to be added. According to the calculation sheet, the calculation idea is to use the process parameters at 50 degrees as the benchmark to calculate the flow rate at any temperature and pressure. Actually, the important thing is the conversion of density. The calculation formula is as follows: Q=0.7 * d ^ 2 * ε * @ sqr (Δ P/ρ) Nm3/h0C101.325kPa, which is the volumetric flow rate required to be displayed on the screen at 0 degrees standard atmospheric pressure. According to the density formula: ρ=P * T50/(P50 * T) * ρ 50, where ρ, P, and T represent values at any temperature and pressure. ρ 50, P50, and T50 represent process reference points at a gauge pressure of 0.04 MPa at 50 degrees Celsius. Combining these two formulas, the program can be completed. 2、 Gas calculation sheet (omitted) III. Program analysis 1. Instantaneous temperature measurement: must be converted to absolute Celsius temperature; Namely+273.15 pressure quantity: must be converted to absolute pressure for calculation. The calculation of gauge pressure and atmospheric pressure compensation is based on the calculation formula, and the data is saved in the register of the PLC. At the same time, monitor on the intouch screen

2. The cumulative amount is triggered by a rising edge scan in 2 seconds, which converts the compensated flow rate value (Nm3/h) to a flow rate value of every 2 seconds for cumulative summation. The screen has a reset and reset function.

1. Calculate the height of the liquid level (horizontal tank meter Zhengzhou calculation formula) h (m)=P/(ρ gas * g)? P=the value measured by the differential pressure transmitter, unit Kpa 2=0.45~0.48: Look at the maximum density value after normal gas filling of the flowmeter, which can be set, unit: g/cm: ρ gas 2g=9.8 Gravity acceleration: m/s:

2. Calculate the tank volume: 1. If hr (r is the radius of the inner tank container, unit: m, item: 1.2m), the angle LAOB=2 * arccos ((r-h)/r), unit: radian section 2AOBAOBS=π r * L/(2 π) - (1/2) * r2 * sinL Display volume=S * Tank length: Project tank length 12.1 meters:: 2: If h=r (r is the radius of the inner tank container, unit: m, project is 1.2m), 2 cross-sectional area S=(1/2) * π r Display volume=S * Tank length: Project tank length 12.1 meters:: 3: If h>r (r is the radius of the inner tank container, unit: m, project is 1.2m), angle L=2 * arccos (h-r)/r), unit: radians AOB2 cross-sectional area S=π r * (2 π - L)/(2) π) +(1/2) * r2 * sinLuAOBAOB Display volume=S * Tank length: Pro

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