Which one is better in measuring liquid phase flow, vortex flowmeter or orifice flowmeter?

When it comes to accuracy, the vortex street must be higher, and the pressure loss of the orifice plate is relatively large. I think the vortex street is better!

Each of these two flow meters has its own advantages and disadvantages.: 1. Vortex flowmeter: A vortex flowmeter is an instrument in which a non-streamlined vortex generator is placed in the fluid. The fluid alternately separates and releases two series of regularly staggered vortices on both sides of the generator. Vortex flowmeters can be divided according to frequency detection methods: stress type, strain type, capacitive type, thermal type, vibration type, photoelectric type and ultrasonic type, etc. Vortex flowmeter is the youngest type of flowmeter, but it has developed rapidly and has become a common type of flowmeter. 1. Advantages (1) The vortex flowmeter has no moving parts, the measuring element has a simple structure, reliable performance and long service life. (2) The vortex flowmeter has a wide measuring range. The range ratio can generally reach 1: 10. (3) The volume flow rate of the vortex flowmeter is not affected by thermal parameters such as temperature, pressure, density or viscosity of the fluid being measured. Generally no separate calibration is required. It can measure the flow of liquid, gas or steam. (4) It causes small pressure loss. (5) The accuracy is high, the repeatability is 0.5%, and the maintenance is small. 2. Disadvantages (1) The volume flow rate of the vortex flowmeter under working conditions is not affected by thermal parameters such as temperature, pressure, and density of the fluid being measured, but the final measurement result of liquid or steam should be mass flow rate, and for gas, the final measurement result should be standard volume flow rate. Both mass flow rate or standard volume flow rate must be converted by fluid density, and changes in fluid density caused by changes in fluid operating conditions must be considered. (2) The main factors causing flow measurement errors are: Measurement errors caused by uneven flow rates in pipelines ； Unable to accurately determine the medium density when fluid conditions change ； Wet saturated steam is measured assuming dry saturated steam. If these errors are not limited or eliminated, the total measurement error of the vortex flowmeter will be very large. (3) Poor vibration resistance. External vibration will cause the vortex flowmeter to produce measurement errors and even fail to work properly. The impact of high flow velocity of channel fluid will cause additional vibration on the cantilever of the vortex generator, which will reduce the measurement accuracy. The influence of large pipe diameter is more obvious. (4) Poor adaptability to measuring dirty media. The generator body of the vortex flowmeter is easily contaminated by the medium or entangled with dirt, which changes the geometric size and greatly affects the measurement accuracy. (5) The straight pipe section has high requirements. Experts pointed out that the straight pipe section of the vortex flowmeter must ensure 40D in the front and 20D in the back to meet the measurement requirements. (6) Poor temperature resistance. Vortex flowmeters generally can only measure fluid flow in media below 300°C. 2. Orifice flow meter: 1. Advantages (1) The standard throttling parts are universally used around the world and have been recognized by international standards organizations. They can be put into use without real flow calibration and are unique among flow meters. (2) The structure is easy to copy, simple, strong, stable and reliable in performance, and low in price. ； (3) It has a wide range of applications, including all single-phase fluids (liquid, gas, steam) and partially mixed-phase flows. Products are available for pipe diameters and working conditions (temperature, pressure) in general production processes. (4) The detection parts and differential pressure display instruments can be produced by different manufacturers to facilitate specialized scale production. ； 2. Disadvantages (1) The repeatability and accuracy of measurement are at a medium level among flow meters. Due to the intricate influence of many factors, the accuracy is difficult to improve. (2) The range is narrow. Since the flow coefficient is related to Reynolds number, the general range is only 3:1 ~ 4:1. (3) There are long straight pipe length requirements, which are generally difficult to meet. Especially for larger pipe diameters, the problem is more prominent ； (4) Large pressure loss ； Usually, in order to maintain the normal operation of an orifice plate flowmeter, the water pump requires additional power to overcome the pressure loss of the orifice plate. This additional power consumption can be determined directly from pressure loss and flow calculations. It consumes approximately tens of thousands of additional kilowatt hours of electricity per year, equivalent to tens of thousands of RMB. (5) The orifice plate uses sharp angles in the inner hole to ensure accuracy, so it is sensitive to corrosion, wear, scaling, and dirt. The accuracy of long-term use is difficult to guarantee, and it needs to be dismantled and inspected once a year. (6) Flange connection is used, which is prone to problems such as running, popping, dripping and leaking. * * Increased maintenance workload. This post was last edited by zlky2005 on 2009-3-7 11:19 ]

Simply put, vortex flow meters are better than orifice plate measurements. The former can guarantee accuracy, while the measurement accuracy of the latter varies greatly depending on usage. ； Vortex street installation is also very convenient. The disadvantage is that the installation location cannot produce vibration.

ask a question: Is it better to use vortex street or orifice plate for boiler feed water flow meter? Our factory has many boiler feed water flow meters, one of which is the outlet of the pump and may vibrate.

Boiler water supply generally uses orifice plates, because although the orifice plates are not as accurate as the vortex street, they are stable and reliable.

Personally think: Vortex streets are easily disturbed by external vibrations, and we have never bought one in recent years. The pressure loss of the orifice plate is indeed a problem in this era of energy conservation. Especially pipes with fast flow rates. We are considering using a velocity averaging tube

Nowadays, differential pressure flow meters are not limited to orifice plates. V-cone and elbow flow meters are also a good choice! Of course, the cost is much higher than that of orifice plates, but the problems of orifice plates are also solved.

Our flow meter selection is given by the design institute. We choose vortex street for the process package, while the design institute chooses orifice plate for detailed design. Which of the design institutes you mentioned did not provide data sheets.

The orifice plate has* * Standard, it can be calibrated. Although theoretically, the V-shaped cone can make the fluid in the pipe have basically the same speed from the pipe wall to the center, but there is no * * standards, cannot be a cadre school,

Why not use electromagnetic flowmeter to measure liquids?