The HUALIU Elbow Flowmeter (model HL-WG) belongs, like the traditional orifice plate flowmeter, to the category of differential-pressure flowmeters; the difference lies in how the differential pressure is generated. The orifice plate produces differential pressure through the throttling principle, whereas the elbow sensor measures flow using the inertia principle. As fluid passes through the elbow, it is constrained to follow an approximately circular path; the resulting centrifugal force acts on the inner and outer sides of the elbow, creating a pressure difference between the inner and outer walls of the sensor. The magnitude of this difference is related to the fluid density, the mean flow velocity and the radius of curvature of the circular motion, and follows Newton's laws of motion, from which the flow rate is derived.

This flowmeter retains the advantages of differential-pressure flowmeters—simple structure, stable performance and accurate measurement—while overcoming their drawbacks of high pressure loss, susceptibility to clogging and difficult maintenance. Because the elbow sensor has no insertion element or primary throttling element, it imposes no additional pressure loss on the measured fluid during measurement, saving pumping power and energy. Straight-run requirements are relaxed, with 5D upstream and 2D downstream sufficient for use. The sensor offers excellent resistance to temperature, pressure, corrosion, wear and vibration, is insensitive to minor wear, and after special treatment can achieve a service life comparable to that of the pipeline.

The HUALIU Elbow Flowmeter system achieves a measuring accuracy of class 0.5~1.5 and a repeatability of 0.2%, covers nominal diameters from DN10 to DN2000, and can measure liquids, gases, steam and other media, with optional pressure and temperature compensation. With outstanding energy savings and high stability, accuracy and adaptability, it is widely used for the flow measurement of steam, coal gas, natural gas, hot and cold water, oil, air and other media in the thermal power, cogeneration, metallurgical, petrochemical and related industries. It can be welded directly onto the pipeline, offering easy installation, wear resistance and maintenance-free operation.