Thread Content
1. Advantages of vortex flow meters. (1) Simple structure, robust, and easy to install and maintain. There is no need for pressure transfer pipes or three-valve assemblies, reducing leaks, blockages, and freezing. (2) It has a wide measurement range; by selecting an appropriate diameter, the range ratio can reach 20:1. (3) It has high accuracy, generally ±(1～1.5)%R. (4) Outputs pulse signals proportional to the flow rate, with no zero drift. (5) Minimal pressure drop, approximately 1/4 to 1/2 of that of a throttle-type differential pressure flow meter. (6) Within a certain range of Reynolds numbers, the output frequency is unaffected by the fluid properties (density, viscosity) and composition; in other words, the instrument coefficient depends only on the shape and size of the vortex generator and the pipeline. 2. Advantages of throttle-type differential pressure flow meters: (1) Wide range of applications. It is applicable to all single-phase fluids, as well as to some multiphase flows such as gas-solid, vapor-liquid, and solid-liquid flows. (2) The standard orifice plate structure in throttle-type differential pressure flowmeters is easy to replicate, simple and robust, offers stable and reliable performance, and is inexpensive. It can be used without real-flow calibration, which is rare among flowmeters. (3) It is insensitive to vibration and has exceptionally excellent interference resistance. (4) Suitable for high temperature, high pressure, large diameters, and low flow rates. 3. Limitations of vortex flowmeters: (1) The larger the diameter, the lower the resolution; generally, these flowmeters are used for diameters below DN400 when the pipe is full. (2) It is sensitive to mechanical vibrations in pipelines and should not be used in areas with strong vibrations. (3) When the fluid has pressure fluctuations or flow rate fluctuations, the indicated value becomes significantly high, resulting in a significant impact; therefore, it is not suitable for pulsating flows. (4) The sensor also faces difficulties when the fluid temperature is too high; generally, the fluid temperature should be ≤420°C. 4. Limitations of throttle-type differential pressure flow meters: (1) Narrow range; since there is a quadratic relationship between the instrument signal (differential pressure) and flow rate, the typical range is only 3:1 to 4:1. (2) The measurement accuracy is of medium level in flow meters. Due to the complex interplay of numerous factors, it is difficult to improve accuracy. (3) The pressure transfer pipeline between the throttling device and the differential pressure display instrument is a weak link, prone to failures such as leakage, blockage, freezing, and signal distortion. (4) High pressure drop (referring to orifice plates and nozzles). (5) The on-site installation requirements are quite high; for example, long straight pipe sections (referring to orifice plates and nozzles) are generally difficult to obtain.