The difference between ultrasonic, turbine and Roots gas flowmeters in natural gas measurement

What are the differences between the use of ultrasonic, turbine and Roots gas flowmeters in natural gas metering?

At present, the widely used flowmeters in natural gas flowmeter measurement are: gas turbine flowmeter, gas ultrasonic flowmeter, gas Roots flowmeter, etc. These flowmeters have their own advantages and disadvantages. The

gas turbine flowmeter is a velocity flow measurement instrument. When the fluid flows into the flowmeter, it is rectified and accelerated under the action of the leading fluid (or rectifier). Since the turbine blades are at a certain angle to the fluid flow direction, the turbine generates a torque at this time. After overcoming the friction torque and fluid resistance torque, the turbine begins to rotate. Within a certain flow range, the angular velocity of the turbine rotation is proportional to the fluid volume flow rate. According to the principle of electromagnetic induction, a magnetic sensor is used to induce a pulse signal proportional to the fluid volume flow rate from a synchronously rotating reference wheel. The signal is amplified, filtered, and shaped, and then sent to the intelligent volume corrector. It is processed together with temperature, pressure and other signals and displayed on the LCD screen. High accuracy and simple measurement. However, because of the impeller, there is a pressure difference between the upper and lower ends of the flowmeter. The pressure that the impeller has been bearing has high requirements for the bearings of the impeller. This is why the turbine flowmeter needs to be replaced every 2-3 years. Its price is relatively moderate. It is widely used in urban gas stations and other places.

Gas ultrasonic flowmeter is a new flow measurement method that has emerged in recent years. Its design is relatively complex, so the price is relatively high. At present, there are relatively few manufacturers that can produce it, and the scope of use is limited to natural gas transmission pipelines. It is basically used by large enterprises. It has high measurement accuracy and less maintenance. The

gas Roots flowmeter is a volumetric flow meter. When the gas passes through the flowmeter, the pressure difference generated between the inlet and outlet acts on a pair of Roots wheels connected to high-precision synchronous gears, thereby driving the Roots wheels to rotate. During this period, the closed space formed between the Roots wheel and the inner wall of the shell and the gland-the metering chamber is periodically inflated and exhausted. The number of revolutions of the Roots wheel is proportional to the volume of gas passing through the flowmeter. The rotation of the Roots wheel is transmitted to the mechanical counter (or output flow pulse signal) through the magnetic coupler, thereby accumulating the volume flowing through the metering chamber to achieve the purpose of metering. The gas Roots flowmeter has a small starting flow rate and a wide range ratio, and is suitable for measuring gas flow with large load changes. The metering accuracy is not affected by pressure and flow changes, and the performance is stable and the service life is long. It is generally used in large restaurants, star-rated hotels and other civil places. Its price is the cheapest among the three flowmeters.

The three flowmeters are used in different occasions and have different prices, but they all measure accurately and with high precision. (end)