The ultrasound flow meter, a non-contact, high-precision flow measurement device, has been widely applied in a number of sectors, including municipal water, petrochemicals and electrical metallurgicals, with the advantage of being free of pressure, easy to install and suitable for various media. Compared to traditional flow meters, they do not need to be exposed to measured media. They can effectively avoid the effects of medium corrosion and congestion on equipment, while measuring its wide scope and precision as the preferred equipment for modern industrial flow measurement. This paper provides a comprehensive analysis of ultrasound flow metrics in terms of working principles, core types, technological advantages and industry applications, and enables firms to understand and select their models with precision。
I. Core working principles of the ultrasound flow meter
The measurements of ultrasound flow meters are mainly divided into the time difference method and the doppler effect method, of which the time difference method is most widely applied。
The time difference method calculates the flow rate by measuring the time difference (Δt) between the direction of the supersonic wave and the direction of the reverse stream, combined with the geometric parameters of the pipeline, with a core formula of v=2t0cosθl⋅Δt (v for current speed, l for the length of the ultrasonic path, t0 for time of transmission at static times, and θ for the angle of the path and current speed). The doppler effect method calculates the flow speed (Δf) from a particle or bubble reflecting ultrasound in the fluid, which is a formula of v=2f0c⋅Δf (c for ultrasound velocity in the fluid and f0 for launch frequency) and applies to the measurement of fluids containing impurities。
In any case, ultrasound flow meters do not require the destruction of pipeline structures, allow for non-intrusive measurements, avoid interference of the traditional flow meters with fluid flows, while reducing the corrosiveness and wear of the medium to the equipment and prolonging its useful life。
Ii. Main types and characteristics of ultrasound flow meters
Depending on the manner of installation and the differences in structure, the ultrasound flow count is divided into three main categories, each of which corresponds to different conditions, and the enterprise may choose as necessary:
1. Extra-packed ultrasound flow meters: non-intrusive installation without the need to cut pipes, stop production, applicable to a variety of piping materials such as metals, plastics, low cost and easy to operate. The disadvantage is to measure accuracy, which is influenced more by piping and wall thickness, suitable for routine work such as temporary measurements, agricultural irrigation, urban water supply, etc., and up to > 1. 5% fs。
2. Pyramid ultrasound flowometers: sensors are directly embedded in the pipe to measure high stability and accuracy, applicable to high pressure, high temperature conditions and up to ± 0. 2% fs. Its structure is compact, suitable for long-term flow monitoring in industries such as petrochemicals, electricity, metallurgy, etc., and it allows seamless interface with self-controlled systems to achieve intelligent control。
3. Inserted ultrasound flow meters: a combination of installation convenience and measurement accuracy, which can be dismantled with pressure, applicable to non-filled or large calibre pipe measurements and maintenance of convenience. The network flow monitoring, which is widely applied to municipal water supply and sewage treatment plants, has reduced system leakage rates from 25 per cent to 12 per cent for a coastal sewage treatment plant, saving more than 8 million tons of water annually。
Iii. Technological advantages and applications of ultrasound flow meters
Core technical advantages:
First, non-contact measurements, no pressure loss and extremely low energy losses
The second is the measurement of a wide range with current speeds of 0. 01 m/s to 15 m/s, with a scale of up to 100 m:1 and a high rate of fluctuations in the flow of suitable work
Third is highly adaptable, working temperatures - 40°c to 160°c, pressure level pn40 and protection level ip65/ip67/ip68
Fourth is the abundance of output signals supporting 4-20ma, rs485, modbus and wireless agreements (lora/nb-iot) that match the construction needs of digital chemical plants。
Main application scenarios: municipal water sector, for piped water network, sewage treatment plant access monitoring; petrochemical industry, for flow measurement of crude oil, chemical solution; electricity industry, for circulation monitoring of recycled water, steam; food beverages industry, for non-pollution measurement of sanitary media (e. G. Milk, juice); semiconductor industry, for flow control of high-purity water and corrosive solution。
Selection and use of attention
The selection needs to be combined with the characteristics of the medium, the measurement of precision needs and the installation of the environment: the hydrometeorization rate is 5 ms/cm (e. G., electrolyte added for pure water); corrosive substances need to choose polytetrafluoroethylene liner and algae electrode; trade settlement or precision control selection ±0. 2% fs accuracy, with general monitoring of 0. 5% fs. It is required to ensure the length of the direct tube segment (the first 5d ~ 10d, the second 3d ~ 5d), distance from a strong electromagnetic field (e. G., a large electric power plant) and distance from 5 m to avoid affecting the accuracy of the measurement。
We are the qing dynasty instrumentator, a source factory that sells directly, develops and sells together, devotes 20 years of attention to fluid monitoring and control equipment and sells nearly 160 countries worldwide; the main product consists of electromagnetic flow meters, vortex rotation meters, ultrasound flow meters, vortex flow meters, vortex flow meters, heat gas flow meters, ultrasound radar positionometers, flow-table heat gauges, etc.
