Gear flowmeters are a type of positive displacement flowmeter that measure fluid flow by counting the number of rotations of precision-machined gears inside the meter. The fluid passing through the meter drives the gears to rotate, and each rotation corresponds to a fixed volume of fluid, enabling high-precision cumulative measurement. They are widely used in scenarios requiring accurate metering of viscous media, with the following core characteristics:
1. High measurement accuracy and excellent repeatability
The measurement principle is based on fixed-displacement metering, so the accuracy is less affected by fluid flow rate, pressure and viscosity changes. The typical measurement accuracy can reach ±0.2%~±0.5%R, and the repeatability error is within ±0.1%. This feature makes it ideal for trade settlement scenarios such as refined oil, lubricating oil, and high-value chemical reagent metering.
2. Strong adaptability to high-viscosity media
Unlike velocity-type flowmeters (e.g., vortex, electromagnetic flowmeters) whose accuracy decreases with increasing fluid viscosity, gear flowmeters perform better when measuring high-viscosity media. They can accurately measure fluids with viscosity ranging from 10 to 1,000,000 mPa·s, such as heavy oil, resin, syrup, grease, and polymer solutions, and are suitable for media containing a small amount of impurities without affecting measurement stability.
3. Compact structure and high-pressure resistance
The internal components are simple and compact, with no complex transmission mechanisms. The meter body is usually made of stainless steel or cast iron, and can withstand high working pressures (up to 6.4 MPa or even higher for customized models). It is suitable for installation in narrow spaces and high-pressure pipeline systems, such as hydraulic oil circuits in industrial equipment and high-pressure fuel delivery pipelines.
4. Wide turndown ratio and stable performance at low flow rates
The turndown ratio can reach 1:10~1:50, which can accurately measure both high-flow and low-flow conditions. Especially for low-flow rate scenarios where other flowmeters are difficult to measure stably, gear flowmeters can still maintain high measurement accuracy, making them suitable for precision batching and small-flow continuous metering in chemical, food and pharmaceutical industries.
5. Low sensitivity to upstream and downstream pipeline conditions
There is no strict requirement for straight pipe sections during installation. Unlike electromagnetic or vortex flowmeters that need long straight pipe sections to stabilize the flow field, gear flowmeters can be installed close to elbows, valves and other pipeline accessories, which greatly reduces the difficulty of on-site installation and saves pipeline layout space.
6. Relatively high maintenance requirements
The precision-machined gear clearances are very small. If the fluid contains large particles or impurities, it is easy to cause gear wear, jamming or damage. Therefore, it is necessary to install a high-precision filter upstream of the meter. In addition, regular maintenance (such as replacing sealing parts and lubricating oil) is required to ensure the tightness and rotation flexibility of the gears, resulting in higher long-term operation and maintenance costs compared with non-contact flowmeters.
Post time: Dec-30-2025