What type of flow meter is used for large-diameter gas flow?

There are many types; the bipyramidal one is quite good

Delta Ba is preferred, followed by Toba, and then A Liu Ba: lower pressure loss. If pressure loss is not a concern, V-cones and porous orifice plates can be considered.

It still depends on the process conditions; Anuba, nozzles, and Venturi tubes can all be used. Anuba is cheaper. For such a large pipe diameter, there must be certain restrictions regarding pressure drop, and flow rate is also an influencing factor – everything needs to be considered together

If the medium is relatively clean and free of particles, a piston flow meter can be used; it has no pressure loss, is easy to install, and is cost-effective. For non-pure media, an inline ultrasonic flow meter is recommended, although it is slightly more expensive.

Please specify the process conditions; with what you’ve said, the flowmeter recommended is not reliable at all.

An insert-type thermal gas mass flow meter can be used. ﹡ Thermal gas flow meters do not require temperature or pressure compensation; they can directly measure the volumetric and mass flow rates of gases under standard conditions. ﹡ Thermal gas flow meters can display the gas flow velocity, and thus can function as gas velocity meters. ﹡ The lower limit for flow measurement with thermal gas flow meters is extremely low – measurement can start almost from zero, which is unmatched by other types of gas flow meters. ﹡ Thermal gas flow meters offer high precision and fast response times, with a range ratio of up to 100:1, making them particularly suitable for metering purposes. ﹡ There is almost no pressure loss with thermal gas flow meters, making them ideal for measuring gases at large diameters and low flow velocities. ﹡ These meters have no moving parts inside; their sensors are enclosed in sturdy 316L stainless steel or tantalum, which prevents contamination and sticking, allowing them to measure highly corrosive gases such as chlorine and phosgene. It has been successfully applied in industries such as chlor-alkali, pesticides, and phosphorus trichloride. ‡ Thermal gas flow meters are available in integrated or separate configurations, as well as in pipe-mounted or insert-type forms; their overall structure is simple, resulting in minimal requirements for installation and maintenance. ‡ High-temperature thermal gas flow meters can operate up to 500 degrees Celsius, and they are designed specifically for use in CEMS systems for measuring flue gas in power plants during desulfurization and denitrification processes. ‡ Thermal gas flow meters can be equipped with flow straightening devices, which significantly reduce the requirements regarding the length of straight sections before and after the meter. ‡ They can also be fitted with ball valve-type non-flow-disrupting devices that allow for online installation and removal without having to interrupt the flow in the pipeline