A liquid volumetric flowmeter is a high-precision measuring instrument that divides a fixed volume of liquid through moving parts and converts the rotational speed into flow rate.

• High Precision: It is one of the most accurate types among all flow meters, generally achieving ±0.5%, and the precision type can reach ±0.1% to ±0.2%. It is the preferred choice for liquid trade handovers, especially for high-value liquids.
• Insensitive to Viscosity Changes: This is one of its core advantages. The measurement accuracy is basically unaffected by changes in fluid viscosity, making it highly suitable for measuring viscous media such as crude oil, heavy oil, lubricating oil, and polymers.
• No Requirement for Straight Pipe Sections: The measurement principle is based on direct volumetric measurement and is not sensitive to flow velocity distribution. Therefore, it has very low requirements for the straight pipe sections before and after the installation, and even no straight pipe sections are needed.
• High Range Ratio: It has a wide range ratio, typically reaching 10:1, and high-performance models can reach 100:1, maintaining high accuracy over a wide range of flow rates.
• Direct volume measurement without external power supply (mechanical type): The mechanical meter head can directly display cumulative flow without power supply, making it highly suitable for safety and explosion-proof environments and on-site indication.

• Viscosity Adaptation: Conventional 0.3~1000 mPa・s, special models can cover up to 2000 mPa・s (such as high-temperature helical gear type).
• Pipe Diameter and Flow Rate: Pipe diameter DN4~DN400mm, maximum flow rate can reach 2200 m³/h (for large-diameter dual-rotor models).
• Working Condition Tolerance: Pressure 0.6~9.6 MPa, temperature -29℃~250℃ (high-temperature models require heat dissipation design).
• Output Method: Mechanical counting, pulse, 4-20mA analog signal, intelligent models support Modbus/HART and wireless transmission.

There are mainly the following types of liquid volumetric flowmeters, which have different structures but share the same principle:

• Intelligent upgrade: It is expected that the proportion of intelligent models will exceed 50% by 2025, featuring integrated self-diagnosis, remote calibration and predictive maintenance.
• Accelerated domestic substitution: Domestic high-end products have obtained API/ATEX certifications, with prices 30% to 40% lower than imported ones, and their market share has reached 52%.
• Material innovation: The application of ceramic bearings and low-friction coatings has extended the service life from 5 years to over 10 years.

Liquid volumetric flowmeters are synonymous with precision and reliability. They measure the volume of fluid in the most direct mechanical way, and hold an unshakable dominant position in the precise measurement of medium to high viscosity liquids. Despite their strict requirements for medium cleanliness and pressure loss, their unparalleled accuracy and insensitivity to viscosity make them irreplaceable key equipment in trade handovers and critical process control in industries such as petroleum, chemical engineering, and food.