The HUALIU wedge flowmeter is a new type of throttling differential-pressure flow measuring instrument that replaces the conventional orifice plate with a special wedge-shaped (V-shaped) throttling element. Because the wedge apex points downward, media carrying suspended particles or of high viscosity and prone to crystallization do not stagnate or accumulate upstream or downstream of the element as they flow past, giving it good self-cleaning capability. The instrument has a simple structure, no moving parts, high wear resistance and stable, reliable operation, with a service life of over ten years, making it especially suitable for high-viscosity, low-Reynolds-number applications and for low-velocity, low-flow, large-bore measurements.

Its operating principle is that a differential pressure is generated as the fluid passes through the wedge throttling element, the square root of which is proportional to the volume or mass flow rate; the range is determined by the wedge-height-to-bore ratio (H/D). Even at extremely low pipe Reynolds numbers (as low as Re=500), a stable square-root relationship is maintained between flow and differential pressure, so the minimum measurable Reynolds number is far better than that of an ordinary orifice flowmeter. After calibration the accuracy can reach class 0.5, and even without calibration it reaches around 3%, with a permanent pressure loss lower than that of an orifice plate.

The HUALIU wedge flowmeter is widely used for flow measurement of high-viscosity heavy oil, residual oil, diesel, engine oil, slurry, coal-tar pitch and coal-water slurry, as well as industrial gas, coke-oven gas, blast-furnace gas, town gas, hydrogen, nitrogen, air, steam, wastewater and other media. Using a diaphragm-sealed dual-flange DP transmitter together with a wedge throttling element made of corrosion-resistant material, it can also reliably measure corrosive media. The integral version requires no impulse piping for field installation and can be connected directly to the pipe by thread or flange, saving construction time and simplifying maintenance.