Venturi tube flowmeter

First, the measuring principle NV2118 Venturi tube flowmeter patent products, a new generation of differential pressure flow measurement instruments, basic measuring principle is based on the law of conservation of energy - Bernoulli equation and continuity equation flow based flow measurement. Venturi tube is made of a circular measuring tube and placed in the measuring tube and the measuring tube coaxial core body constituted special. Special radially outer surface of the core member has a classic venturi tube inner surface similar to the profile shape geometry, and between the inner surface of the measuring tube constituting an overcurrent diameter annular gap. Fluid flow through the venturi tube fluid flow through throttling process with classical venturi tube, the throttling process is substantially similar to the annular orifice. Such structural features within the venturi tube, so that there is no similar sharp edged orifice plate erosion and contamination problems using the process, and to the front of the tube and throttle fluid velocity gradient distribution of various possible non-axisymmetric flow velocity distribution of effective adjustment (rectification), enabling flow measurement with high accuracy and high stability. Second, the performance characteristics of the measurement accuracy for high precision differential pressure transmitter can achieve accurate flow measurement. Good measurement stability, long-term to maintain a constant flow coefficient, long test cycle. Measuring range of (turndown ratio) wide, without software correction to the second table of 10: 1 or more. For medium adaptable, capable of measuring high pressure, low flow, high moisture and gases of various dirty fluids. To install straight pipe requirements low, can effectively prevent or reduce the measurement system additional measurement uncertainty. Small pressure loss, saving energy. Third, the technical parameters of the discharge coefficient uncertainty: better than ± 0.5% resistance to medium pressure: 5MPa below the range may be higher than 5MPa ratio: 10: 1 or wider resistance to medium temperature: below 600 ℃ Pressure loss: measuring differential pressure 1/5 (about 1/3 of orifice pressure drop) For diameter: ND25mm ~ 1500mm straight pipe requirements: general upstream 3D, downstream 1D applicable Reynolds: ReD≥4 × 103 (ReD limit may be less than 4 × 103, this time the discharge coefficient uncertainty relative increase) is adapted to measure media: all kinds of liquids, gases and steam